1 /*
2 * Copyright © 2014 Red Hat
3 *
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that copyright
7 * notice and this permission notice appear in supporting documentation, and
8 * that the name of the copyright holders not be used in advertising or
9 * publicity pertaining to distribution of the software without specific,
10 * written prior permission. The copyright holders make no representations
11 * about the suitability of this software for any purpose. It is provided "as
12 * is" without express or implied warranty.
13 *
14 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20 * OF THIS SOFTWARE.
21 */
22
23 #include <linux/bitfield.h>
24 #include <linux/delay.h>
25 #include <linux/errno.h>
26 #include <linux/i2c.h>
27 #include <linux/init.h>
28 #include <linux/kernel.h>
29 #include <linux/random.h>
30 #include <linux/sched.h>
31 #include <linux/seq_file.h>
32 #include <linux/iopoll.h>
33
34 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
35 #include <linux/stacktrace.h>
36 #include <linux/sort.h>
37 #include <linux/timekeeping.h>
38 #include <linux/math64.h>
39 #endif
40
41 #include <drm/display/drm_dp_mst_helper.h>
42 #include <drm/drm_atomic.h>
43 #include <drm/drm_atomic_helper.h>
44 #include <drm/drm_drv.h>
45 #include <drm/drm_edid.h>
46 #include <drm/drm_fixed.h>
47 #include <drm/drm_print.h>
48 #include <drm/drm_probe_helper.h>
49
50 #include "drm_dp_helper_internal.h"
51 #include "drm_dp_mst_topology_internal.h"
52
53 /**
54 * DOC: dp mst helper
55 *
56 * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
57 * protocol. The helpers contain a topology manager and bandwidth manager.
58 * The helpers encapsulate the sending and received of sideband msgs.
59 */
60 struct drm_dp_pending_up_req {
61 struct drm_dp_sideband_msg_hdr hdr;
62 struct drm_dp_sideband_msg_req_body msg;
63 struct list_head next;
64 };
65
66 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
67 char *buf);
68
69 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
70
71 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
72 int id, u8 start_slot, u8 num_slots);
73
74 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
75 struct drm_dp_mst_port *port,
76 int offset, int size, u8 *bytes);
77 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
78 struct drm_dp_mst_port *port,
79 int offset, int size, u8 *bytes);
80
81 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
82 struct drm_dp_mst_branch *mstb);
83
84 static void
85 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
86 struct drm_dp_mst_branch *mstb);
87
88 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
89 struct drm_dp_mst_branch *mstb,
90 struct drm_dp_mst_port *port);
91 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
92 u8 *guid);
93
94 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
95 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
96 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
97
98 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
99 struct drm_dp_mst_branch *branch);
100
101 #define DBG_PREFIX "[dp_mst]"
102
103 #define DP_STR(x) [DP_ ## x] = #x
104
drm_dp_mst_req_type_str(u8 req_type)105 static const char *drm_dp_mst_req_type_str(u8 req_type)
106 {
107 static const char * const req_type_str[] = {
108 DP_STR(GET_MSG_TRANSACTION_VERSION),
109 DP_STR(LINK_ADDRESS),
110 DP_STR(CONNECTION_STATUS_NOTIFY),
111 DP_STR(ENUM_PATH_RESOURCES),
112 DP_STR(ALLOCATE_PAYLOAD),
113 DP_STR(QUERY_PAYLOAD),
114 DP_STR(RESOURCE_STATUS_NOTIFY),
115 DP_STR(CLEAR_PAYLOAD_ID_TABLE),
116 DP_STR(REMOTE_DPCD_READ),
117 DP_STR(REMOTE_DPCD_WRITE),
118 DP_STR(REMOTE_I2C_READ),
119 DP_STR(REMOTE_I2C_WRITE),
120 DP_STR(POWER_UP_PHY),
121 DP_STR(POWER_DOWN_PHY),
122 DP_STR(SINK_EVENT_NOTIFY),
123 DP_STR(QUERY_STREAM_ENC_STATUS),
124 };
125
126 if (req_type >= ARRAY_SIZE(req_type_str) ||
127 !req_type_str[req_type])
128 return "unknown";
129
130 return req_type_str[req_type];
131 }
132
133 #undef DP_STR
134 #define DP_STR(x) [DP_NAK_ ## x] = #x
135
drm_dp_mst_nak_reason_str(u8 nak_reason)136 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
137 {
138 static const char * const nak_reason_str[] = {
139 DP_STR(WRITE_FAILURE),
140 DP_STR(INVALID_READ),
141 DP_STR(CRC_FAILURE),
142 DP_STR(BAD_PARAM),
143 DP_STR(DEFER),
144 DP_STR(LINK_FAILURE),
145 DP_STR(NO_RESOURCES),
146 DP_STR(DPCD_FAIL),
147 DP_STR(I2C_NAK),
148 DP_STR(ALLOCATE_FAIL),
149 };
150
151 if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
152 !nak_reason_str[nak_reason])
153 return "unknown";
154
155 return nak_reason_str[nak_reason];
156 }
157
158 #undef DP_STR
159 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
160
drm_dp_mst_sideband_tx_state_str(int state)161 static const char *drm_dp_mst_sideband_tx_state_str(int state)
162 {
163 static const char * const sideband_reason_str[] = {
164 DP_STR(QUEUED),
165 DP_STR(START_SEND),
166 DP_STR(SENT),
167 DP_STR(RX),
168 DP_STR(TIMEOUT),
169 };
170
171 if (state >= ARRAY_SIZE(sideband_reason_str) ||
172 !sideband_reason_str[state])
173 return "unknown";
174
175 return sideband_reason_str[state];
176 }
177
178 static int
drm_dp_mst_rad_to_str(const u8 rad[8],u8 lct,char * out,size_t len)179 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
180 {
181 int i;
182 u8 unpacked_rad[16];
183
184 for (i = 0; i < lct; i++) {
185 if (i % 2)
186 unpacked_rad[i] = rad[i / 2] >> 4;
187 else
188 unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
189 }
190
191 /* TODO: Eventually add something to printk so we can format the rad
192 * like this: 1.2.3
193 */
194 return snprintf(out, len, "%*phC", lct, unpacked_rad);
195 }
196
197 /* sideband msg handling */
drm_dp_msg_header_crc4(const uint8_t * data,size_t num_nibbles)198 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
199 {
200 u8 bitmask = 0x80;
201 u8 bitshift = 7;
202 u8 array_index = 0;
203 int number_of_bits = num_nibbles * 4;
204 u8 remainder = 0;
205
206 while (number_of_bits != 0) {
207 number_of_bits--;
208 remainder <<= 1;
209 remainder |= (data[array_index] & bitmask) >> bitshift;
210 bitmask >>= 1;
211 bitshift--;
212 if (bitmask == 0) {
213 bitmask = 0x80;
214 bitshift = 7;
215 array_index++;
216 }
217 if ((remainder & 0x10) == 0x10)
218 remainder ^= 0x13;
219 }
220
221 number_of_bits = 4;
222 while (number_of_bits != 0) {
223 number_of_bits--;
224 remainder <<= 1;
225 if ((remainder & 0x10) != 0)
226 remainder ^= 0x13;
227 }
228
229 return remainder;
230 }
231
drm_dp_msg_data_crc4(const uint8_t * data,u8 number_of_bytes)232 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
233 {
234 u8 bitmask = 0x80;
235 u8 bitshift = 7;
236 u8 array_index = 0;
237 int number_of_bits = number_of_bytes * 8;
238 u16 remainder = 0;
239
240 while (number_of_bits != 0) {
241 number_of_bits--;
242 remainder <<= 1;
243 remainder |= (data[array_index] & bitmask) >> bitshift;
244 bitmask >>= 1;
245 bitshift--;
246 if (bitmask == 0) {
247 bitmask = 0x80;
248 bitshift = 7;
249 array_index++;
250 }
251 if ((remainder & 0x100) == 0x100)
252 remainder ^= 0xd5;
253 }
254
255 number_of_bits = 8;
256 while (number_of_bits != 0) {
257 number_of_bits--;
258 remainder <<= 1;
259 if ((remainder & 0x100) != 0)
260 remainder ^= 0xd5;
261 }
262
263 return remainder & 0xff;
264 }
drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr * hdr)265 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
266 {
267 u8 size = 3;
268
269 size += (hdr->lct / 2);
270 return size;
271 }
272
drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr * hdr,u8 * buf,int * len)273 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
274 u8 *buf, int *len)
275 {
276 int idx = 0;
277 int i;
278 u8 crc4;
279
280 buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
281 for (i = 0; i < (hdr->lct / 2); i++)
282 buf[idx++] = hdr->rad[i];
283 buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
284 (hdr->msg_len & 0x3f);
285 buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
286
287 crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
288 buf[idx - 1] |= (crc4 & 0xf);
289
290 *len = idx;
291 }
292
drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_hdr * hdr,u8 * buf,int buflen,u8 * hdrlen)293 static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
294 struct drm_dp_sideband_msg_hdr *hdr,
295 u8 *buf, int buflen, u8 *hdrlen)
296 {
297 u8 crc4;
298 u8 len;
299 int i;
300 u8 idx;
301
302 if (buf[0] == 0)
303 return false;
304 len = 3;
305 len += ((buf[0] & 0xf0) >> 4) / 2;
306 if (len > buflen)
307 return false;
308 crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
309
310 if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
311 drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
312 return false;
313 }
314
315 hdr->lct = (buf[0] & 0xf0) >> 4;
316 hdr->lcr = (buf[0] & 0xf);
317 idx = 1;
318 for (i = 0; i < (hdr->lct / 2); i++)
319 hdr->rad[i] = buf[idx++];
320 hdr->broadcast = (buf[idx] >> 7) & 0x1;
321 hdr->path_msg = (buf[idx] >> 6) & 0x1;
322 hdr->msg_len = buf[idx] & 0x3f;
323 idx++;
324 hdr->somt = (buf[idx] >> 7) & 0x1;
325 hdr->eomt = (buf[idx] >> 6) & 0x1;
326 hdr->seqno = (buf[idx] >> 4) & 0x1;
327 idx++;
328 *hdrlen = idx;
329 return true;
330 }
331
332 void
drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body * req,struct drm_dp_sideband_msg_tx * raw)333 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
334 struct drm_dp_sideband_msg_tx *raw)
335 {
336 int idx = 0;
337 int i;
338 u8 *buf = raw->msg;
339
340 buf[idx++] = req->req_type & 0x7f;
341
342 switch (req->req_type) {
343 case DP_ENUM_PATH_RESOURCES:
344 case DP_POWER_DOWN_PHY:
345 case DP_POWER_UP_PHY:
346 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
347 idx++;
348 break;
349 case DP_ALLOCATE_PAYLOAD:
350 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
351 (req->u.allocate_payload.number_sdp_streams & 0xf);
352 idx++;
353 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
354 idx++;
355 buf[idx] = (req->u.allocate_payload.pbn >> 8);
356 idx++;
357 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
358 idx++;
359 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
360 buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
361 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
362 idx++;
363 }
364 if (req->u.allocate_payload.number_sdp_streams & 1) {
365 i = req->u.allocate_payload.number_sdp_streams - 1;
366 buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
367 idx++;
368 }
369 break;
370 case DP_QUERY_PAYLOAD:
371 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
372 idx++;
373 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
374 idx++;
375 break;
376 case DP_REMOTE_DPCD_READ:
377 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
378 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
379 idx++;
380 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
381 idx++;
382 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
383 idx++;
384 buf[idx] = (req->u.dpcd_read.num_bytes);
385 idx++;
386 break;
387
388 case DP_REMOTE_DPCD_WRITE:
389 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
390 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
391 idx++;
392 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
393 idx++;
394 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
395 idx++;
396 buf[idx] = (req->u.dpcd_write.num_bytes);
397 idx++;
398 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
399 idx += req->u.dpcd_write.num_bytes;
400 break;
401 case DP_REMOTE_I2C_READ:
402 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
403 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
404 idx++;
405 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
406 buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
407 idx++;
408 buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
409 idx++;
410 memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
411 idx += req->u.i2c_read.transactions[i].num_bytes;
412
413 buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
414 buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
415 idx++;
416 }
417 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
418 idx++;
419 buf[idx] = (req->u.i2c_read.num_bytes_read);
420 idx++;
421 break;
422
423 case DP_REMOTE_I2C_WRITE:
424 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
425 idx++;
426 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
427 idx++;
428 buf[idx] = (req->u.i2c_write.num_bytes);
429 idx++;
430 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
431 idx += req->u.i2c_write.num_bytes;
432 break;
433 case DP_QUERY_STREAM_ENC_STATUS: {
434 const struct drm_dp_query_stream_enc_status *msg;
435
436 msg = &req->u.enc_status;
437 buf[idx] = msg->stream_id;
438 idx++;
439 memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
440 idx += sizeof(msg->client_id);
441 buf[idx] = 0;
442 buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
443 buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
444 buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
445 buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
446 idx++;
447 }
448 break;
449 }
450 raw->cur_len = idx;
451 }
452 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
453
454 /* Decode a sideband request we've encoded, mainly used for debugging */
455 int
drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx * raw,struct drm_dp_sideband_msg_req_body * req)456 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
457 struct drm_dp_sideband_msg_req_body *req)
458 {
459 const u8 *buf = raw->msg;
460 int i, idx = 0;
461
462 req->req_type = buf[idx++] & 0x7f;
463 switch (req->req_type) {
464 case DP_ENUM_PATH_RESOURCES:
465 case DP_POWER_DOWN_PHY:
466 case DP_POWER_UP_PHY:
467 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
468 break;
469 case DP_ALLOCATE_PAYLOAD:
470 {
471 struct drm_dp_allocate_payload *a =
472 &req->u.allocate_payload;
473
474 a->number_sdp_streams = buf[idx] & 0xf;
475 a->port_number = (buf[idx] >> 4) & 0xf;
476
477 WARN_ON(buf[++idx] & 0x80);
478 a->vcpi = buf[idx] & 0x7f;
479
480 a->pbn = buf[++idx] << 8;
481 a->pbn |= buf[++idx];
482
483 idx++;
484 for (i = 0; i < a->number_sdp_streams; i++) {
485 a->sdp_stream_sink[i] =
486 (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
487 }
488 }
489 break;
490 case DP_QUERY_PAYLOAD:
491 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
492 WARN_ON(buf[++idx] & 0x80);
493 req->u.query_payload.vcpi = buf[idx] & 0x7f;
494 break;
495 case DP_REMOTE_DPCD_READ:
496 {
497 struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
498
499 r->port_number = (buf[idx] >> 4) & 0xf;
500
501 r->dpcd_address = (buf[idx] << 16) & 0xf0000;
502 r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
503 r->dpcd_address |= buf[++idx] & 0xff;
504
505 r->num_bytes = buf[++idx];
506 }
507 break;
508 case DP_REMOTE_DPCD_WRITE:
509 {
510 struct drm_dp_remote_dpcd_write *w =
511 &req->u.dpcd_write;
512
513 w->port_number = (buf[idx] >> 4) & 0xf;
514
515 w->dpcd_address = (buf[idx] << 16) & 0xf0000;
516 w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
517 w->dpcd_address |= buf[++idx] & 0xff;
518
519 w->num_bytes = buf[++idx];
520
521 w->bytes = kmemdup(&buf[++idx], w->num_bytes,
522 GFP_KERNEL);
523 if (!w->bytes)
524 return -ENOMEM;
525 }
526 break;
527 case DP_REMOTE_I2C_READ:
528 {
529 struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
530 struct drm_dp_remote_i2c_read_tx *tx;
531 bool failed = false;
532
533 r->num_transactions = buf[idx] & 0x3;
534 r->port_number = (buf[idx] >> 4) & 0xf;
535 for (i = 0; i < r->num_transactions; i++) {
536 tx = &r->transactions[i];
537
538 tx->i2c_dev_id = buf[++idx] & 0x7f;
539 tx->num_bytes = buf[++idx];
540 tx->bytes = kmemdup(&buf[++idx],
541 tx->num_bytes,
542 GFP_KERNEL);
543 if (!tx->bytes) {
544 failed = true;
545 break;
546 }
547 idx += tx->num_bytes;
548 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
549 tx->i2c_transaction_delay = buf[idx] & 0xf;
550 }
551
552 if (failed) {
553 for (i = 0; i < r->num_transactions; i++) {
554 tx = &r->transactions[i];
555 kfree(tx->bytes);
556 }
557 return -ENOMEM;
558 }
559
560 r->read_i2c_device_id = buf[++idx] & 0x7f;
561 r->num_bytes_read = buf[++idx];
562 }
563 break;
564 case DP_REMOTE_I2C_WRITE:
565 {
566 struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
567
568 w->port_number = (buf[idx] >> 4) & 0xf;
569 w->write_i2c_device_id = buf[++idx] & 0x7f;
570 w->num_bytes = buf[++idx];
571 w->bytes = kmemdup(&buf[++idx], w->num_bytes,
572 GFP_KERNEL);
573 if (!w->bytes)
574 return -ENOMEM;
575 }
576 break;
577 case DP_QUERY_STREAM_ENC_STATUS:
578 req->u.enc_status.stream_id = buf[idx++];
579 for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
580 req->u.enc_status.client_id[i] = buf[idx++];
581
582 req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
583 buf[idx]);
584 req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
585 buf[idx]);
586 req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
587 buf[idx]);
588 req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
589 buf[idx]);
590 break;
591 }
592
593 return 0;
594 }
595 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
596
597 void
drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body * req,int indent,struct drm_printer * printer)598 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
599 int indent, struct drm_printer *printer)
600 {
601 int i;
602
603 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
604 if (req->req_type == DP_LINK_ADDRESS) {
605 /* No contents to print */
606 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
607 return;
608 }
609
610 P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
611 indent++;
612
613 switch (req->req_type) {
614 case DP_ENUM_PATH_RESOURCES:
615 case DP_POWER_DOWN_PHY:
616 case DP_POWER_UP_PHY:
617 P("port=%d\n", req->u.port_num.port_number);
618 break;
619 case DP_ALLOCATE_PAYLOAD:
620 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
621 req->u.allocate_payload.port_number,
622 req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
623 req->u.allocate_payload.number_sdp_streams,
624 req->u.allocate_payload.number_sdp_streams,
625 req->u.allocate_payload.sdp_stream_sink);
626 break;
627 case DP_QUERY_PAYLOAD:
628 P("port=%d vcpi=%d\n",
629 req->u.query_payload.port_number,
630 req->u.query_payload.vcpi);
631 break;
632 case DP_REMOTE_DPCD_READ:
633 P("port=%d dpcd_addr=%05x len=%d\n",
634 req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
635 req->u.dpcd_read.num_bytes);
636 break;
637 case DP_REMOTE_DPCD_WRITE:
638 P("port=%d addr=%05x len=%d: %*ph\n",
639 req->u.dpcd_write.port_number,
640 req->u.dpcd_write.dpcd_address,
641 req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
642 req->u.dpcd_write.bytes);
643 break;
644 case DP_REMOTE_I2C_READ:
645 P("port=%d num_tx=%d id=%d size=%d:\n",
646 req->u.i2c_read.port_number,
647 req->u.i2c_read.num_transactions,
648 req->u.i2c_read.read_i2c_device_id,
649 req->u.i2c_read.num_bytes_read);
650
651 indent++;
652 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
653 const struct drm_dp_remote_i2c_read_tx *rtx =
654 &req->u.i2c_read.transactions[i];
655
656 P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
657 i, rtx->i2c_dev_id, rtx->num_bytes,
658 rtx->no_stop_bit, rtx->i2c_transaction_delay,
659 rtx->num_bytes, rtx->bytes);
660 }
661 break;
662 case DP_REMOTE_I2C_WRITE:
663 P("port=%d id=%d size=%d: %*ph\n",
664 req->u.i2c_write.port_number,
665 req->u.i2c_write.write_i2c_device_id,
666 req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
667 req->u.i2c_write.bytes);
668 break;
669 case DP_QUERY_STREAM_ENC_STATUS:
670 P("stream_id=%u client_id=%*ph stream_event=%x "
671 "valid_event=%d stream_behavior=%x valid_behavior=%d",
672 req->u.enc_status.stream_id,
673 (int)ARRAY_SIZE(req->u.enc_status.client_id),
674 req->u.enc_status.client_id, req->u.enc_status.stream_event,
675 req->u.enc_status.valid_stream_event,
676 req->u.enc_status.stream_behavior,
677 req->u.enc_status.valid_stream_behavior);
678 break;
679 default:
680 P("???\n");
681 break;
682 }
683 #undef P
684 }
685 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
686
687 static inline void
drm_dp_mst_dump_sideband_msg_tx(struct drm_printer * p,const struct drm_dp_sideband_msg_tx * txmsg)688 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
689 const struct drm_dp_sideband_msg_tx *txmsg)
690 {
691 struct drm_dp_sideband_msg_req_body req;
692 char buf[64];
693 int ret;
694 int i;
695
696 drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
697 sizeof(buf));
698 drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
699 txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
700 drm_dp_mst_sideband_tx_state_str(txmsg->state),
701 txmsg->path_msg, buf);
702
703 ret = drm_dp_decode_sideband_req(txmsg, &req);
704 if (ret) {
705 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
706 return;
707 }
708 drm_dp_dump_sideband_msg_req_body(&req, 1, p);
709
710 switch (req.req_type) {
711 case DP_REMOTE_DPCD_WRITE:
712 kfree(req.u.dpcd_write.bytes);
713 break;
714 case DP_REMOTE_I2C_READ:
715 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
716 kfree(req.u.i2c_read.transactions[i].bytes);
717 break;
718 case DP_REMOTE_I2C_WRITE:
719 kfree(req.u.i2c_write.bytes);
720 break;
721 }
722 }
723
drm_dp_crc_sideband_chunk_req(u8 * msg,u8 len)724 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
725 {
726 u8 crc4;
727
728 crc4 = drm_dp_msg_data_crc4(msg, len);
729 msg[len] = crc4;
730 }
731
drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body * rep,struct drm_dp_sideband_msg_tx * raw)732 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
733 struct drm_dp_sideband_msg_tx *raw)
734 {
735 int idx = 0;
736 u8 *buf = raw->msg;
737
738 buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
739
740 raw->cur_len = idx;
741 }
742
drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx * msg,struct drm_dp_sideband_msg_hdr * hdr,u8 hdrlen)743 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
744 struct drm_dp_sideband_msg_hdr *hdr,
745 u8 hdrlen)
746 {
747 /*
748 * ignore out-of-order messages or messages that are part of a
749 * failed transaction
750 */
751 if (!hdr->somt && !msg->have_somt)
752 return false;
753
754 /* get length contained in this portion */
755 msg->curchunk_idx = 0;
756 msg->curchunk_len = hdr->msg_len;
757 msg->curchunk_hdrlen = hdrlen;
758
759 /* we have already gotten an somt - don't bother parsing */
760 if (hdr->somt && msg->have_somt)
761 return false;
762
763 if (hdr->somt) {
764 memcpy(&msg->initial_hdr, hdr,
765 sizeof(struct drm_dp_sideband_msg_hdr));
766 msg->have_somt = true;
767 }
768 if (hdr->eomt)
769 msg->have_eomt = true;
770
771 return true;
772 }
773
774 /* this adds a chunk of msg to the builder to get the final msg */
drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx * msg,u8 * replybuf,u8 replybuflen)775 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
776 u8 *replybuf, u8 replybuflen)
777 {
778 u8 crc4;
779
780 memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
781 msg->curchunk_idx += replybuflen;
782
783 if (msg->curchunk_idx >= msg->curchunk_len) {
784 /* do CRC */
785 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
786 if (crc4 != msg->chunk[msg->curchunk_len - 1])
787 print_hex_dump(KERN_DEBUG, "wrong crc",
788 DUMP_PREFIX_NONE, 16, 1,
789 msg->chunk, msg->curchunk_len, false);
790 /* copy chunk into bigger msg */
791 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
792 msg->curlen += msg->curchunk_len - 1;
793 }
794 return true;
795 }
796
drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)797 static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
798 struct drm_dp_sideband_msg_rx *raw,
799 struct drm_dp_sideband_msg_reply_body *repmsg)
800 {
801 int idx = 1;
802 int i;
803
804 memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
805 idx += 16;
806 repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
807 idx++;
808 if (idx > raw->curlen)
809 goto fail_len;
810 for (i = 0; i < repmsg->u.link_addr.nports; i++) {
811 if (raw->msg[idx] & 0x80)
812 repmsg->u.link_addr.ports[i].input_port = 1;
813
814 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
815 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
816
817 idx++;
818 if (idx > raw->curlen)
819 goto fail_len;
820 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
821 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
822 if (repmsg->u.link_addr.ports[i].input_port == 0)
823 repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
824 idx++;
825 if (idx > raw->curlen)
826 goto fail_len;
827 if (repmsg->u.link_addr.ports[i].input_port == 0) {
828 repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
829 idx++;
830 if (idx > raw->curlen)
831 goto fail_len;
832 memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
833 idx += 16;
834 if (idx > raw->curlen)
835 goto fail_len;
836 repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
837 repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
838 idx++;
839
840 }
841 if (idx > raw->curlen)
842 goto fail_len;
843 }
844
845 return true;
846 fail_len:
847 DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
848 return false;
849 }
850
drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)851 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
852 struct drm_dp_sideband_msg_reply_body *repmsg)
853 {
854 int idx = 1;
855
856 repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
857 idx++;
858 if (idx > raw->curlen)
859 goto fail_len;
860 repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
861 idx++;
862 if (idx > raw->curlen)
863 goto fail_len;
864
865 memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
866 return true;
867 fail_len:
868 DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
869 return false;
870 }
871
drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)872 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
873 struct drm_dp_sideband_msg_reply_body *repmsg)
874 {
875 int idx = 1;
876
877 repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
878 idx++;
879 if (idx > raw->curlen)
880 goto fail_len;
881 return true;
882 fail_len:
883 DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
884 return false;
885 }
886
drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)887 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
888 struct drm_dp_sideband_msg_reply_body *repmsg)
889 {
890 int idx = 1;
891
892 repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
893 idx++;
894 if (idx > raw->curlen)
895 goto fail_len;
896 repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
897 idx++;
898 /* TODO check */
899 memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
900 return true;
901 fail_len:
902 DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
903 return false;
904 }
905
drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)906 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
907 struct drm_dp_sideband_msg_reply_body *repmsg)
908 {
909 int idx = 1;
910
911 repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
912 repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
913 idx++;
914 if (idx > raw->curlen)
915 goto fail_len;
916 repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
917 idx += 2;
918 if (idx > raw->curlen)
919 goto fail_len;
920 repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
921 idx += 2;
922 if (idx > raw->curlen)
923 goto fail_len;
924 return true;
925 fail_len:
926 DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
927 return false;
928 }
929
drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)930 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
931 struct drm_dp_sideband_msg_reply_body *repmsg)
932 {
933 int idx = 1;
934
935 repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
936 idx++;
937 if (idx > raw->curlen)
938 goto fail_len;
939 repmsg->u.allocate_payload.vcpi = raw->msg[idx];
940 idx++;
941 if (idx > raw->curlen)
942 goto fail_len;
943 repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
944 idx += 2;
945 if (idx > raw->curlen)
946 goto fail_len;
947 return true;
948 fail_len:
949 DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
950 return false;
951 }
952
drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)953 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
954 struct drm_dp_sideband_msg_reply_body *repmsg)
955 {
956 int idx = 1;
957
958 repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
959 idx++;
960 if (idx > raw->curlen)
961 goto fail_len;
962 repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
963 idx += 2;
964 if (idx > raw->curlen)
965 goto fail_len;
966 return true;
967 fail_len:
968 DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
969 return false;
970 }
971
drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)972 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
973 struct drm_dp_sideband_msg_reply_body *repmsg)
974 {
975 int idx = 1;
976
977 repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
978 idx++;
979 if (idx > raw->curlen) {
980 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
981 idx, raw->curlen);
982 return false;
983 }
984 return true;
985 }
986
987 static bool
drm_dp_sideband_parse_query_stream_enc_status(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)988 drm_dp_sideband_parse_query_stream_enc_status(
989 struct drm_dp_sideband_msg_rx *raw,
990 struct drm_dp_sideband_msg_reply_body *repmsg)
991 {
992 struct drm_dp_query_stream_enc_status_ack_reply *reply;
993
994 reply = &repmsg->u.enc_status;
995
996 reply->stream_id = raw->msg[3];
997
998 reply->reply_signed = raw->msg[2] & BIT(0);
999
1000 /*
1001 * NOTE: It's my impression from reading the spec that the below parsing
1002 * is correct. However I noticed while testing with an HDCP 1.4 display
1003 * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1004 * would expect both bits to be set. So keep the parsing following the
1005 * spec, but beware reality might not match the spec (at least for some
1006 * configurations).
1007 */
1008 reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1009 reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1010
1011 reply->query_capable_device_present = raw->msg[2] & BIT(5);
1012 reply->legacy_device_present = raw->msg[2] & BIT(6);
1013 reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1014
1015 reply->auth_completed = !!(raw->msg[1] & BIT(3));
1016 reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1017 reply->repeater_present = !!(raw->msg[1] & BIT(5));
1018 reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1019
1020 return true;
1021 }
1022
drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * msg)1023 static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1024 struct drm_dp_sideband_msg_rx *raw,
1025 struct drm_dp_sideband_msg_reply_body *msg)
1026 {
1027 memset(msg, 0, sizeof(*msg));
1028 msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1029 msg->req_type = (raw->msg[0] & 0x7f);
1030
1031 if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1032 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1033 msg->u.nak.reason = raw->msg[17];
1034 msg->u.nak.nak_data = raw->msg[18];
1035 return false;
1036 }
1037
1038 switch (msg->req_type) {
1039 case DP_LINK_ADDRESS:
1040 return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1041 case DP_QUERY_PAYLOAD:
1042 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1043 case DP_REMOTE_DPCD_READ:
1044 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1045 case DP_REMOTE_DPCD_WRITE:
1046 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1047 case DP_REMOTE_I2C_READ:
1048 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1049 case DP_REMOTE_I2C_WRITE:
1050 return true; /* since there's nothing to parse */
1051 case DP_ENUM_PATH_RESOURCES:
1052 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1053 case DP_ALLOCATE_PAYLOAD:
1054 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1055 case DP_POWER_DOWN_PHY:
1056 case DP_POWER_UP_PHY:
1057 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1058 case DP_CLEAR_PAYLOAD_ID_TABLE:
1059 return true; /* since there's nothing to parse */
1060 case DP_QUERY_STREAM_ENC_STATUS:
1061 return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1062 default:
1063 drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1064 msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1065 return false;
1066 }
1067 }
1068
1069 static bool
drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1070 drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1071 struct drm_dp_sideband_msg_rx *raw,
1072 struct drm_dp_sideband_msg_req_body *msg)
1073 {
1074 int idx = 1;
1075
1076 msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1077 idx++;
1078 if (idx > raw->curlen)
1079 goto fail_len;
1080
1081 memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1082 idx += 16;
1083 if (idx > raw->curlen)
1084 goto fail_len;
1085
1086 msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1087 msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1088 msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1089 msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1090 msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1091 idx++;
1092 return true;
1093 fail_len:
1094 drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1095 idx, raw->curlen);
1096 return false;
1097 }
1098
drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1099 static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1100 struct drm_dp_sideband_msg_rx *raw,
1101 struct drm_dp_sideband_msg_req_body *msg)
1102 {
1103 int idx = 1;
1104
1105 msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1106 idx++;
1107 if (idx > raw->curlen)
1108 goto fail_len;
1109
1110 memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1111 idx += 16;
1112 if (idx > raw->curlen)
1113 goto fail_len;
1114
1115 msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1116 idx++;
1117 return true;
1118 fail_len:
1119 drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1120 return false;
1121 }
1122
drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1123 static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1124 struct drm_dp_sideband_msg_rx *raw,
1125 struct drm_dp_sideband_msg_req_body *msg)
1126 {
1127 memset(msg, 0, sizeof(*msg));
1128 msg->req_type = (raw->msg[0] & 0x7f);
1129
1130 switch (msg->req_type) {
1131 case DP_CONNECTION_STATUS_NOTIFY:
1132 return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1133 case DP_RESOURCE_STATUS_NOTIFY:
1134 return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1135 default:
1136 drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1137 msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1138 return false;
1139 }
1140 }
1141
build_dpcd_write(struct drm_dp_sideband_msg_tx * msg,u8 port_num,u32 offset,u8 num_bytes,u8 * bytes)1142 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1143 u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1144 {
1145 struct drm_dp_sideband_msg_req_body req;
1146
1147 req.req_type = DP_REMOTE_DPCD_WRITE;
1148 req.u.dpcd_write.port_number = port_num;
1149 req.u.dpcd_write.dpcd_address = offset;
1150 req.u.dpcd_write.num_bytes = num_bytes;
1151 req.u.dpcd_write.bytes = bytes;
1152 drm_dp_encode_sideband_req(&req, msg);
1153 }
1154
build_link_address(struct drm_dp_sideband_msg_tx * msg)1155 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1156 {
1157 struct drm_dp_sideband_msg_req_body req;
1158
1159 req.req_type = DP_LINK_ADDRESS;
1160 drm_dp_encode_sideband_req(&req, msg);
1161 }
1162
build_clear_payload_id_table(struct drm_dp_sideband_msg_tx * msg)1163 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1164 {
1165 struct drm_dp_sideband_msg_req_body req;
1166
1167 req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1168 drm_dp_encode_sideband_req(&req, msg);
1169 msg->path_msg = true;
1170 }
1171
build_enum_path_resources(struct drm_dp_sideband_msg_tx * msg,int port_num)1172 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1173 int port_num)
1174 {
1175 struct drm_dp_sideband_msg_req_body req;
1176
1177 req.req_type = DP_ENUM_PATH_RESOURCES;
1178 req.u.port_num.port_number = port_num;
1179 drm_dp_encode_sideband_req(&req, msg);
1180 msg->path_msg = true;
1181 return 0;
1182 }
1183
build_allocate_payload(struct drm_dp_sideband_msg_tx * msg,int port_num,u8 vcpi,uint16_t pbn,u8 number_sdp_streams,u8 * sdp_stream_sink)1184 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1185 int port_num,
1186 u8 vcpi, uint16_t pbn,
1187 u8 number_sdp_streams,
1188 u8 *sdp_stream_sink)
1189 {
1190 struct drm_dp_sideband_msg_req_body req;
1191
1192 memset(&req, 0, sizeof(req));
1193 req.req_type = DP_ALLOCATE_PAYLOAD;
1194 req.u.allocate_payload.port_number = port_num;
1195 req.u.allocate_payload.vcpi = vcpi;
1196 req.u.allocate_payload.pbn = pbn;
1197 req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1198 memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1199 number_sdp_streams);
1200 drm_dp_encode_sideband_req(&req, msg);
1201 msg->path_msg = true;
1202 }
1203
build_power_updown_phy(struct drm_dp_sideband_msg_tx * msg,int port_num,bool power_up)1204 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1205 int port_num, bool power_up)
1206 {
1207 struct drm_dp_sideband_msg_req_body req;
1208
1209 if (power_up)
1210 req.req_type = DP_POWER_UP_PHY;
1211 else
1212 req.req_type = DP_POWER_DOWN_PHY;
1213
1214 req.u.port_num.port_number = port_num;
1215 drm_dp_encode_sideband_req(&req, msg);
1216 msg->path_msg = true;
1217 }
1218
1219 static int
build_query_stream_enc_status(struct drm_dp_sideband_msg_tx * msg,u8 stream_id,u8 * q_id)1220 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1221 u8 *q_id)
1222 {
1223 struct drm_dp_sideband_msg_req_body req;
1224
1225 req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1226 req.u.enc_status.stream_id = stream_id;
1227 memcpy(req.u.enc_status.client_id, q_id,
1228 sizeof(req.u.enc_status.client_id));
1229 req.u.enc_status.stream_event = 0;
1230 req.u.enc_status.valid_stream_event = false;
1231 req.u.enc_status.stream_behavior = 0;
1232 req.u.enc_status.valid_stream_behavior = false;
1233
1234 drm_dp_encode_sideband_req(&req, msg);
1235 return 0;
1236 }
1237
check_txmsg_state(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg)1238 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1239 struct drm_dp_sideband_msg_tx *txmsg)
1240 {
1241 unsigned int state;
1242
1243 /*
1244 * All updates to txmsg->state are protected by mgr->qlock, and the two
1245 * cases we check here are terminal states. For those the barriers
1246 * provided by the wake_up/wait_event pair are enough.
1247 */
1248 state = READ_ONCE(txmsg->state);
1249 return (state == DRM_DP_SIDEBAND_TX_RX ||
1250 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1251 }
1252
drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch * mstb,struct drm_dp_sideband_msg_tx * txmsg)1253 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1254 struct drm_dp_sideband_msg_tx *txmsg)
1255 {
1256 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1257 unsigned long wait_timeout = msecs_to_jiffies(4000);
1258 unsigned long wait_expires = jiffies + wait_timeout;
1259 int ret;
1260
1261 for (;;) {
1262 /*
1263 * If the driver provides a way for this, change to
1264 * poll-waiting for the MST reply interrupt if we didn't receive
1265 * it for 50 msec. This would cater for cases where the HPD
1266 * pulse signal got lost somewhere, even though the sink raised
1267 * the corresponding MST interrupt correctly. One example is the
1268 * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1269 * filters out short pulses with a duration less than ~540 usec.
1270 *
1271 * The poll period is 50 msec to avoid missing an interrupt
1272 * after the sink has cleared it (after a 110msec timeout
1273 * since it raised the interrupt).
1274 */
1275 ret = wait_event_timeout(mgr->tx_waitq,
1276 check_txmsg_state(mgr, txmsg),
1277 mgr->cbs->poll_hpd_irq ?
1278 msecs_to_jiffies(50) :
1279 wait_timeout);
1280
1281 if (ret || !mgr->cbs->poll_hpd_irq ||
1282 time_after(jiffies, wait_expires))
1283 break;
1284
1285 mgr->cbs->poll_hpd_irq(mgr);
1286 }
1287
1288 mutex_lock(&mgr->qlock);
1289 if (ret > 0) {
1290 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1291 ret = -EIO;
1292 goto out;
1293 }
1294 } else {
1295 drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1296 txmsg, txmsg->state, txmsg->seqno);
1297
1298 /* dump some state */
1299 ret = -EIO;
1300
1301 /* remove from q */
1302 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1303 txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1304 txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1305 list_del(&txmsg->next);
1306 }
1307 out:
1308 if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1309 struct drm_printer p = drm_dbg_printer(mgr->dev, DRM_UT_DP,
1310 DBG_PREFIX);
1311
1312 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1313 }
1314 mutex_unlock(&mgr->qlock);
1315
1316 drm_dp_mst_kick_tx(mgr);
1317 return ret;
1318 }
1319
drm_dp_add_mst_branch_device(u8 lct,u8 * rad)1320 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1321 {
1322 struct drm_dp_mst_branch *mstb;
1323
1324 mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1325 if (!mstb)
1326 return NULL;
1327
1328 mstb->lct = lct;
1329 if (lct > 1)
1330 memcpy(mstb->rad, rad, lct / 2);
1331 INIT_LIST_HEAD(&mstb->ports);
1332 kref_init(&mstb->topology_kref);
1333 kref_init(&mstb->malloc_kref);
1334 return mstb;
1335 }
1336
drm_dp_free_mst_branch_device(struct kref * kref)1337 static void drm_dp_free_mst_branch_device(struct kref *kref)
1338 {
1339 struct drm_dp_mst_branch *mstb =
1340 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1341
1342 if (mstb->port_parent)
1343 drm_dp_mst_put_port_malloc(mstb->port_parent);
1344
1345 kfree(mstb);
1346 }
1347
1348 /**
1349 * DOC: Branch device and port refcounting
1350 *
1351 * Topology refcount overview
1352 * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1353 *
1354 * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1355 * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1356 * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1357 *
1358 * Topology refcounts are not exposed to drivers, and are handled internally
1359 * by the DP MST helpers. The helpers use them in order to prevent the
1360 * in-memory topology state from being changed in the middle of critical
1361 * operations like changing the internal state of payload allocations. This
1362 * means each branch and port will be considered to be connected to the rest
1363 * of the topology until its topology refcount reaches zero. Additionally,
1364 * for ports this means that their associated &struct drm_connector will stay
1365 * registered with userspace until the port's refcount reaches 0.
1366 *
1367 * Malloc refcount overview
1368 * ~~~~~~~~~~~~~~~~~~~~~~~~
1369 *
1370 * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1371 * drm_dp_mst_branch allocated even after all of its topology references have
1372 * been dropped, so that the driver or MST helpers can safely access each
1373 * branch's last known state before it was disconnected from the topology.
1374 * When the malloc refcount of a port or branch reaches 0, the memory
1375 * allocation containing the &struct drm_dp_mst_branch or &struct
1376 * drm_dp_mst_port respectively will be freed.
1377 *
1378 * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1379 * to drivers. As of writing this documentation, there are no drivers that
1380 * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1381 * helpers. Exposing this API to drivers in a race-free manner would take more
1382 * tweaking of the refcounting scheme, however patches are welcome provided
1383 * there is a legitimate driver usecase for this.
1384 *
1385 * Refcount relationships in a topology
1386 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1387 *
1388 * Let's take a look at why the relationship between topology and malloc
1389 * refcounts is designed the way it is.
1390 *
1391 * .. kernel-figure:: dp-mst/topology-figure-1.dot
1392 *
1393 * An example of topology and malloc refs in a DP MST topology with two
1394 * active payloads. Topology refcount increments are indicated by solid
1395 * lines, and malloc refcount increments are indicated by dashed lines.
1396 * Each starts from the branch which incremented the refcount, and ends at
1397 * the branch to which the refcount belongs to, i.e. the arrow points the
1398 * same way as the C pointers used to reference a structure.
1399 *
1400 * As you can see in the above figure, every branch increments the topology
1401 * refcount of its children, and increments the malloc refcount of its
1402 * parent. Additionally, every payload increments the malloc refcount of its
1403 * assigned port by 1.
1404 *
1405 * So, what would happen if MSTB #3 from the above figure was unplugged from
1406 * the system, but the driver hadn't yet removed payload #2 from port #3? The
1407 * topology would start to look like the figure below.
1408 *
1409 * .. kernel-figure:: dp-mst/topology-figure-2.dot
1410 *
1411 * Ports and branch devices which have been released from memory are
1412 * colored grey, and references which have been removed are colored red.
1413 *
1414 * Whenever a port or branch device's topology refcount reaches zero, it will
1415 * decrement the topology refcounts of all its children, the malloc refcount
1416 * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1417 * #4, this means they both have been disconnected from the topology and freed
1418 * from memory. But, because payload #2 is still holding a reference to port
1419 * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1420 * is still accessible from memory. This also means port #3 has not yet
1421 * decremented the malloc refcount of MSTB #3, so its &struct
1422 * drm_dp_mst_branch will also stay allocated in memory until port #3's
1423 * malloc refcount reaches 0.
1424 *
1425 * This relationship is necessary because in order to release payload #2, we
1426 * need to be able to figure out the last relative of port #3 that's still
1427 * connected to the topology. In this case, we would travel up the topology as
1428 * shown below.
1429 *
1430 * .. kernel-figure:: dp-mst/topology-figure-3.dot
1431 *
1432 * And finally, remove payload #2 by communicating with port #2 through
1433 * sideband transactions.
1434 */
1435
1436 /**
1437 * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1438 * device
1439 * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1440 *
1441 * Increments &drm_dp_mst_branch.malloc_kref. When
1442 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1443 * will be released and @mstb may no longer be used.
1444 *
1445 * See also: drm_dp_mst_put_mstb_malloc()
1446 */
1447 static void
drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch * mstb)1448 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1449 {
1450 kref_get(&mstb->malloc_kref);
1451 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1452 }
1453
1454 /**
1455 * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1456 * device
1457 * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1458 *
1459 * Decrements &drm_dp_mst_branch.malloc_kref. When
1460 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1461 * will be released and @mstb may no longer be used.
1462 *
1463 * See also: drm_dp_mst_get_mstb_malloc()
1464 */
1465 static void
drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch * mstb)1466 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1467 {
1468 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1469 kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1470 }
1471
drm_dp_free_mst_port(struct kref * kref)1472 static void drm_dp_free_mst_port(struct kref *kref)
1473 {
1474 struct drm_dp_mst_port *port =
1475 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1476
1477 drm_dp_mst_put_mstb_malloc(port->parent);
1478 kfree(port);
1479 }
1480
1481 /**
1482 * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1483 * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1484 *
1485 * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1486 * reaches 0, the memory allocation for @port will be released and @port may
1487 * no longer be used.
1488 *
1489 * Because @port could potentially be freed at any time by the DP MST helpers
1490 * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1491 * function, drivers that which to make use of &struct drm_dp_mst_port should
1492 * ensure that they grab at least one main malloc reference to their MST ports
1493 * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1494 * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1495 *
1496 * See also: drm_dp_mst_put_port_malloc()
1497 */
1498 void
drm_dp_mst_get_port_malloc(struct drm_dp_mst_port * port)1499 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1500 {
1501 kref_get(&port->malloc_kref);
1502 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1503 }
1504 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1505
1506 /**
1507 * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1508 * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1509 *
1510 * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1511 * reaches 0, the memory allocation for @port will be released and @port may
1512 * no longer be used.
1513 *
1514 * See also: drm_dp_mst_get_port_malloc()
1515 */
1516 void
drm_dp_mst_put_port_malloc(struct drm_dp_mst_port * port)1517 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1518 {
1519 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1520 kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1521 }
1522 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1523
1524 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1525
1526 #define STACK_DEPTH 8
1527
1528 static noinline void
__topology_ref_save(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_ref_history * history,enum drm_dp_mst_topology_ref_type type)1529 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1530 struct drm_dp_mst_topology_ref_history *history,
1531 enum drm_dp_mst_topology_ref_type type)
1532 {
1533 struct drm_dp_mst_topology_ref_entry *entry = NULL;
1534 depot_stack_handle_t backtrace;
1535 ulong stack_entries[STACK_DEPTH];
1536 uint n;
1537 int i;
1538
1539 n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1540 backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1541 if (!backtrace)
1542 return;
1543
1544 /* Try to find an existing entry for this backtrace */
1545 for (i = 0; i < history->len; i++) {
1546 if (history->entries[i].backtrace == backtrace) {
1547 entry = &history->entries[i];
1548 break;
1549 }
1550 }
1551
1552 /* Otherwise add one */
1553 if (!entry) {
1554 struct drm_dp_mst_topology_ref_entry *new;
1555 int new_len = history->len + 1;
1556
1557 new = krealloc(history->entries, sizeof(*new) * new_len,
1558 GFP_KERNEL);
1559 if (!new)
1560 return;
1561
1562 entry = &new[history->len];
1563 history->len = new_len;
1564 history->entries = new;
1565
1566 entry->backtrace = backtrace;
1567 entry->type = type;
1568 entry->count = 0;
1569 }
1570 entry->count++;
1571 entry->ts_nsec = ktime_get_ns();
1572 }
1573
1574 static int
topology_ref_history_cmp(const void * a,const void * b)1575 topology_ref_history_cmp(const void *a, const void *b)
1576 {
1577 const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1578
1579 if (entry_a->ts_nsec > entry_b->ts_nsec)
1580 return 1;
1581 else if (entry_a->ts_nsec < entry_b->ts_nsec)
1582 return -1;
1583 else
1584 return 0;
1585 }
1586
1587 static inline const char *
topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)1588 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1589 {
1590 if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1591 return "get";
1592 else
1593 return "put";
1594 }
1595
1596 static void
__dump_topology_ref_history(struct drm_device * drm,struct drm_dp_mst_topology_ref_history * history,void * ptr,const char * type_str)1597 __dump_topology_ref_history(struct drm_device *drm,
1598 struct drm_dp_mst_topology_ref_history *history,
1599 void *ptr, const char *type_str)
1600 {
1601 struct drm_printer p = drm_dbg_printer(drm, DRM_UT_DP, DBG_PREFIX);
1602 char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1603 int i;
1604
1605 if (!buf)
1606 return;
1607
1608 if (!history->len)
1609 goto out;
1610
1611 /* First, sort the list so that it goes from oldest to newest
1612 * reference entry
1613 */
1614 sort(history->entries, history->len, sizeof(*history->entries),
1615 topology_ref_history_cmp, NULL);
1616
1617 drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1618 type_str, ptr);
1619
1620 for (i = 0; i < history->len; i++) {
1621 const struct drm_dp_mst_topology_ref_entry *entry =
1622 &history->entries[i];
1623 u64 ts_nsec = entry->ts_nsec;
1624 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1625
1626 stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
1627
1628 drm_printf(&p, " %d %ss (last at %5llu.%06u):\n%s",
1629 entry->count,
1630 topology_ref_type_to_str(entry->type),
1631 ts_nsec, rem_nsec / 1000, buf);
1632 }
1633
1634 /* Now free the history, since this is the only time we expose it */
1635 kfree(history->entries);
1636 out:
1637 kfree(buf);
1638 }
1639
1640 static __always_inline void
drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch * mstb)1641 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1642 {
1643 __dump_topology_ref_history(mstb->mgr->dev, &mstb->topology_ref_history,
1644 mstb, "MSTB");
1645 }
1646
1647 static __always_inline void
drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port * port)1648 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1649 {
1650 __dump_topology_ref_history(port->mgr->dev, &port->topology_ref_history,
1651 port, "Port");
1652 }
1653
1654 static __always_inline void
save_mstb_topology_ref(struct drm_dp_mst_branch * mstb,enum drm_dp_mst_topology_ref_type type)1655 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1656 enum drm_dp_mst_topology_ref_type type)
1657 {
1658 __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1659 }
1660
1661 static __always_inline void
save_port_topology_ref(struct drm_dp_mst_port * port,enum drm_dp_mst_topology_ref_type type)1662 save_port_topology_ref(struct drm_dp_mst_port *port,
1663 enum drm_dp_mst_topology_ref_type type)
1664 {
1665 __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1666 }
1667
1668 static inline void
topology_ref_history_lock(struct drm_dp_mst_topology_mgr * mgr)1669 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1670 {
1671 mutex_lock(&mgr->topology_ref_history_lock);
1672 }
1673
1674 static inline void
topology_ref_history_unlock(struct drm_dp_mst_topology_mgr * mgr)1675 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1676 {
1677 mutex_unlock(&mgr->topology_ref_history_lock);
1678 }
1679 #else
1680 static inline void
topology_ref_history_lock(struct drm_dp_mst_topology_mgr * mgr)1681 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1682 static inline void
topology_ref_history_unlock(struct drm_dp_mst_topology_mgr * mgr)1683 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1684 static inline void
drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch * mstb)1685 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1686 static inline void
drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port * port)1687 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1688 #define save_mstb_topology_ref(mstb, type)
1689 #define save_port_topology_ref(port, type)
1690 #endif
1691
1692 struct drm_dp_mst_atomic_payload *
drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state * state,struct drm_dp_mst_port * port)1693 drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
1694 struct drm_dp_mst_port *port)
1695 {
1696 struct drm_dp_mst_atomic_payload *payload;
1697
1698 list_for_each_entry(payload, &state->payloads, next)
1699 if (payload->port == port)
1700 return payload;
1701
1702 return NULL;
1703 }
1704 EXPORT_SYMBOL(drm_atomic_get_mst_payload_state);
1705
drm_dp_destroy_mst_branch_device(struct kref * kref)1706 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1707 {
1708 struct drm_dp_mst_branch *mstb =
1709 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1710 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1711
1712 drm_dp_mst_dump_mstb_topology_history(mstb);
1713
1714 INIT_LIST_HEAD(&mstb->destroy_next);
1715
1716 /*
1717 * This can get called under mgr->mutex, so we need to perform the
1718 * actual destruction of the mstb in another worker
1719 */
1720 mutex_lock(&mgr->delayed_destroy_lock);
1721 list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1722 mutex_unlock(&mgr->delayed_destroy_lock);
1723 queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1724 }
1725
1726 /**
1727 * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1728 * branch device unless it's zero
1729 * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1730 *
1731 * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1732 * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1733 * reached 0). Holding a topology reference implies that a malloc reference
1734 * will be held to @mstb as long as the user holds the topology reference.
1735 *
1736 * Care should be taken to ensure that the user has at least one malloc
1737 * reference to @mstb. If you already have a topology reference to @mstb, you
1738 * should use drm_dp_mst_topology_get_mstb() instead.
1739 *
1740 * See also:
1741 * drm_dp_mst_topology_get_mstb()
1742 * drm_dp_mst_topology_put_mstb()
1743 *
1744 * Returns:
1745 * * 1: A topology reference was grabbed successfully
1746 * * 0: @port is no longer in the topology, no reference was grabbed
1747 */
1748 static int __must_check
drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch * mstb)1749 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1750 {
1751 int ret;
1752
1753 topology_ref_history_lock(mstb->mgr);
1754 ret = kref_get_unless_zero(&mstb->topology_kref);
1755 if (ret) {
1756 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1757 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1758 }
1759
1760 topology_ref_history_unlock(mstb->mgr);
1761
1762 return ret;
1763 }
1764
1765 /**
1766 * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1767 * branch device
1768 * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1769 *
1770 * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1771 * not it's already reached 0. This is only valid to use in scenarios where
1772 * you are already guaranteed to have at least one active topology reference
1773 * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1774 *
1775 * See also:
1776 * drm_dp_mst_topology_try_get_mstb()
1777 * drm_dp_mst_topology_put_mstb()
1778 */
drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch * mstb)1779 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1780 {
1781 topology_ref_history_lock(mstb->mgr);
1782
1783 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1784 WARN_ON(kref_read(&mstb->topology_kref) == 0);
1785 kref_get(&mstb->topology_kref);
1786 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1787
1788 topology_ref_history_unlock(mstb->mgr);
1789 }
1790
1791 /**
1792 * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1793 * device
1794 * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1795 *
1796 * Releases a topology reference from @mstb by decrementing
1797 * &drm_dp_mst_branch.topology_kref.
1798 *
1799 * See also:
1800 * drm_dp_mst_topology_try_get_mstb()
1801 * drm_dp_mst_topology_get_mstb()
1802 */
1803 static void
drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch * mstb)1804 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1805 {
1806 topology_ref_history_lock(mstb->mgr);
1807
1808 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1809 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1810
1811 topology_ref_history_unlock(mstb->mgr);
1812 kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1813 }
1814
drm_dp_destroy_port(struct kref * kref)1815 static void drm_dp_destroy_port(struct kref *kref)
1816 {
1817 struct drm_dp_mst_port *port =
1818 container_of(kref, struct drm_dp_mst_port, topology_kref);
1819 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1820
1821 drm_dp_mst_dump_port_topology_history(port);
1822
1823 /* There's nothing that needs locking to destroy an input port yet */
1824 if (port->input) {
1825 drm_dp_mst_put_port_malloc(port);
1826 return;
1827 }
1828
1829 drm_edid_free(port->cached_edid);
1830
1831 /*
1832 * we can't destroy the connector here, as we might be holding the
1833 * mode_config.mutex from an EDID retrieval
1834 */
1835 mutex_lock(&mgr->delayed_destroy_lock);
1836 list_add(&port->next, &mgr->destroy_port_list);
1837 mutex_unlock(&mgr->delayed_destroy_lock);
1838 queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1839 }
1840
1841 /**
1842 * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1843 * port unless it's zero
1844 * @port: &struct drm_dp_mst_port to increment the topology refcount of
1845 *
1846 * Attempts to grab a topology reference to @port, if it hasn't yet been
1847 * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1848 * 0). Holding a topology reference implies that a malloc reference will be
1849 * held to @port as long as the user holds the topology reference.
1850 *
1851 * Care should be taken to ensure that the user has at least one malloc
1852 * reference to @port. If you already have a topology reference to @port, you
1853 * should use drm_dp_mst_topology_get_port() instead.
1854 *
1855 * See also:
1856 * drm_dp_mst_topology_get_port()
1857 * drm_dp_mst_topology_put_port()
1858 *
1859 * Returns:
1860 * * 1: A topology reference was grabbed successfully
1861 * * 0: @port is no longer in the topology, no reference was grabbed
1862 */
1863 static int __must_check
drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port * port)1864 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1865 {
1866 int ret;
1867
1868 topology_ref_history_lock(port->mgr);
1869 ret = kref_get_unless_zero(&port->topology_kref);
1870 if (ret) {
1871 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1872 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1873 }
1874
1875 topology_ref_history_unlock(port->mgr);
1876 return ret;
1877 }
1878
1879 /**
1880 * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1881 * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1882 *
1883 * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1884 * not it's already reached 0. This is only valid to use in scenarios where
1885 * you are already guaranteed to have at least one active topology reference
1886 * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1887 *
1888 * See also:
1889 * drm_dp_mst_topology_try_get_port()
1890 * drm_dp_mst_topology_put_port()
1891 */
drm_dp_mst_topology_get_port(struct drm_dp_mst_port * port)1892 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1893 {
1894 topology_ref_history_lock(port->mgr);
1895
1896 WARN_ON(kref_read(&port->topology_kref) == 0);
1897 kref_get(&port->topology_kref);
1898 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1899 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1900
1901 topology_ref_history_unlock(port->mgr);
1902 }
1903
1904 /**
1905 * drm_dp_mst_topology_put_port() - release a topology reference to a port
1906 * @port: The &struct drm_dp_mst_port to release the topology reference from
1907 *
1908 * Releases a topology reference from @port by decrementing
1909 * &drm_dp_mst_port.topology_kref.
1910 *
1911 * See also:
1912 * drm_dp_mst_topology_try_get_port()
1913 * drm_dp_mst_topology_get_port()
1914 */
drm_dp_mst_topology_put_port(struct drm_dp_mst_port * port)1915 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1916 {
1917 topology_ref_history_lock(port->mgr);
1918
1919 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1920 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1921
1922 topology_ref_history_unlock(port->mgr);
1923 kref_put(&port->topology_kref, drm_dp_destroy_port);
1924 }
1925
1926 static struct drm_dp_mst_branch *
drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_branch * to_find)1927 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1928 struct drm_dp_mst_branch *to_find)
1929 {
1930 struct drm_dp_mst_port *port;
1931 struct drm_dp_mst_branch *rmstb;
1932
1933 if (to_find == mstb)
1934 return mstb;
1935
1936 list_for_each_entry(port, &mstb->ports, next) {
1937 if (port->mstb) {
1938 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1939 port->mstb, to_find);
1940 if (rmstb)
1941 return rmstb;
1942 }
1943 }
1944 return NULL;
1945 }
1946
1947 static struct drm_dp_mst_branch *
drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)1948 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1949 struct drm_dp_mst_branch *mstb)
1950 {
1951 struct drm_dp_mst_branch *rmstb = NULL;
1952
1953 mutex_lock(&mgr->lock);
1954 if (mgr->mst_primary) {
1955 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1956 mgr->mst_primary, mstb);
1957
1958 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1959 rmstb = NULL;
1960 }
1961 mutex_unlock(&mgr->lock);
1962 return rmstb;
1963 }
1964
1965 static struct drm_dp_mst_port *
drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * to_find)1966 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1967 struct drm_dp_mst_port *to_find)
1968 {
1969 struct drm_dp_mst_port *port, *mport;
1970
1971 list_for_each_entry(port, &mstb->ports, next) {
1972 if (port == to_find)
1973 return port;
1974
1975 if (port->mstb) {
1976 mport = drm_dp_mst_topology_get_port_validated_locked(
1977 port->mstb, to_find);
1978 if (mport)
1979 return mport;
1980 }
1981 }
1982 return NULL;
1983 }
1984
1985 static struct drm_dp_mst_port *
drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)1986 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
1987 struct drm_dp_mst_port *port)
1988 {
1989 struct drm_dp_mst_port *rport = NULL;
1990
1991 mutex_lock(&mgr->lock);
1992 if (mgr->mst_primary) {
1993 rport = drm_dp_mst_topology_get_port_validated_locked(
1994 mgr->mst_primary, port);
1995
1996 if (rport && !drm_dp_mst_topology_try_get_port(rport))
1997 rport = NULL;
1998 }
1999 mutex_unlock(&mgr->lock);
2000 return rport;
2001 }
2002
drm_dp_get_port(struct drm_dp_mst_branch * mstb,u8 port_num)2003 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2004 {
2005 struct drm_dp_mst_port *port;
2006 int ret;
2007
2008 list_for_each_entry(port, &mstb->ports, next) {
2009 if (port->port_num == port_num) {
2010 ret = drm_dp_mst_topology_try_get_port(port);
2011 return ret ? port : NULL;
2012 }
2013 }
2014
2015 return NULL;
2016 }
2017
2018 /*
2019 * calculate a new RAD for this MST branch device
2020 * if parent has an LCT of 2 then it has 1 nibble of RAD,
2021 * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2022 */
drm_dp_calculate_rad(struct drm_dp_mst_port * port,u8 * rad)2023 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2024 u8 *rad)
2025 {
2026 int parent_lct = port->parent->lct;
2027 int shift = 4;
2028 int idx = (parent_lct - 1) / 2;
2029
2030 if (parent_lct > 1) {
2031 memcpy(rad, port->parent->rad, idx + 1);
2032 shift = (parent_lct % 2) ? 4 : 0;
2033 } else
2034 rad[0] = 0;
2035
2036 rad[idx] |= port->port_num << shift;
2037 return parent_lct + 1;
2038 }
2039
drm_dp_mst_is_end_device(u8 pdt,bool mcs)2040 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2041 {
2042 switch (pdt) {
2043 case DP_PEER_DEVICE_DP_LEGACY_CONV:
2044 case DP_PEER_DEVICE_SST_SINK:
2045 return true;
2046 case DP_PEER_DEVICE_MST_BRANCHING:
2047 /* For sst branch device */
2048 if (!mcs)
2049 return true;
2050
2051 return false;
2052 }
2053 return true;
2054 }
2055
2056 static int
drm_dp_port_set_pdt(struct drm_dp_mst_port * port,u8 new_pdt,bool new_mcs)2057 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2058 bool new_mcs)
2059 {
2060 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2061 struct drm_dp_mst_branch *mstb;
2062 u8 rad[8], lct;
2063 int ret = 0;
2064
2065 if (port->pdt == new_pdt && port->mcs == new_mcs)
2066 return 0;
2067
2068 /* Teardown the old pdt, if there is one */
2069 if (port->pdt != DP_PEER_DEVICE_NONE) {
2070 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2071 /*
2072 * If the new PDT would also have an i2c bus,
2073 * don't bother with reregistering it
2074 */
2075 if (new_pdt != DP_PEER_DEVICE_NONE &&
2076 drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2077 port->pdt = new_pdt;
2078 port->mcs = new_mcs;
2079 return 0;
2080 }
2081
2082 /* remove i2c over sideband */
2083 drm_dp_mst_unregister_i2c_bus(port);
2084 } else {
2085 mutex_lock(&mgr->lock);
2086 drm_dp_mst_topology_put_mstb(port->mstb);
2087 port->mstb = NULL;
2088 mutex_unlock(&mgr->lock);
2089 }
2090 }
2091
2092 port->pdt = new_pdt;
2093 port->mcs = new_mcs;
2094
2095 if (port->pdt != DP_PEER_DEVICE_NONE) {
2096 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2097 /* add i2c over sideband */
2098 ret = drm_dp_mst_register_i2c_bus(port);
2099 } else {
2100 lct = drm_dp_calculate_rad(port, rad);
2101 mstb = drm_dp_add_mst_branch_device(lct, rad);
2102 if (!mstb) {
2103 ret = -ENOMEM;
2104 drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2105 goto out;
2106 }
2107
2108 mutex_lock(&mgr->lock);
2109 port->mstb = mstb;
2110 mstb->mgr = port->mgr;
2111 mstb->port_parent = port;
2112
2113 /*
2114 * Make sure this port's memory allocation stays
2115 * around until its child MSTB releases it
2116 */
2117 drm_dp_mst_get_port_malloc(port);
2118 mutex_unlock(&mgr->lock);
2119
2120 /* And make sure we send a link address for this */
2121 ret = 1;
2122 }
2123 }
2124
2125 out:
2126 if (ret < 0)
2127 port->pdt = DP_PEER_DEVICE_NONE;
2128 return ret;
2129 }
2130
2131 /**
2132 * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2133 * @aux: Fake sideband AUX CH
2134 * @offset: address of the (first) register to read
2135 * @buffer: buffer to store the register values
2136 * @size: number of bytes in @buffer
2137 *
2138 * Performs the same functionality for remote devices via
2139 * sideband messaging as drm_dp_dpcd_read() does for local
2140 * devices via actual AUX CH.
2141 *
2142 * Return: Number of bytes read, or negative error code on failure.
2143 */
drm_dp_mst_dpcd_read(struct drm_dp_aux * aux,unsigned int offset,void * buffer,size_t size)2144 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2145 unsigned int offset, void *buffer, size_t size)
2146 {
2147 struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2148 aux);
2149
2150 return drm_dp_send_dpcd_read(port->mgr, port,
2151 offset, size, buffer);
2152 }
2153
2154 /**
2155 * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2156 * @aux: Fake sideband AUX CH
2157 * @offset: address of the (first) register to write
2158 * @buffer: buffer containing the values to write
2159 * @size: number of bytes in @buffer
2160 *
2161 * Performs the same functionality for remote devices via
2162 * sideband messaging as drm_dp_dpcd_write() does for local
2163 * devices via actual AUX CH.
2164 *
2165 * Return: number of bytes written on success, negative error code on failure.
2166 */
drm_dp_mst_dpcd_write(struct drm_dp_aux * aux,unsigned int offset,void * buffer,size_t size)2167 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2168 unsigned int offset, void *buffer, size_t size)
2169 {
2170 struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2171 aux);
2172
2173 return drm_dp_send_dpcd_write(port->mgr, port,
2174 offset, size, buffer);
2175 }
2176
drm_dp_check_mstb_guid(struct drm_dp_mst_branch * mstb,u8 * guid)2177 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2178 {
2179 int ret = 0;
2180
2181 memcpy(mstb->guid, guid, 16);
2182
2183 if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2184 if (mstb->port_parent) {
2185 ret = drm_dp_send_dpcd_write(mstb->mgr,
2186 mstb->port_parent,
2187 DP_GUID, 16, mstb->guid);
2188 } else {
2189 ret = drm_dp_dpcd_write(mstb->mgr->aux,
2190 DP_GUID, mstb->guid, 16);
2191 }
2192 }
2193
2194 if (ret < 16 && ret > 0)
2195 return -EPROTO;
2196
2197 return ret == 16 ? 0 : ret;
2198 }
2199
build_mst_prop_path(const struct drm_dp_mst_branch * mstb,int pnum,char * proppath,size_t proppath_size)2200 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2201 int pnum,
2202 char *proppath,
2203 size_t proppath_size)
2204 {
2205 int i;
2206 char temp[8];
2207
2208 snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2209 for (i = 0; i < (mstb->lct - 1); i++) {
2210 int shift = (i % 2) ? 0 : 4;
2211 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2212
2213 snprintf(temp, sizeof(temp), "-%d", port_num);
2214 strlcat(proppath, temp, proppath_size);
2215 }
2216 snprintf(temp, sizeof(temp), "-%d", pnum);
2217 strlcat(proppath, temp, proppath_size);
2218 }
2219
2220 /**
2221 * drm_dp_mst_connector_late_register() - Late MST connector registration
2222 * @connector: The MST connector
2223 * @port: The MST port for this connector
2224 *
2225 * Helper to register the remote aux device for this MST port. Drivers should
2226 * call this from their mst connector's late_register hook to enable MST aux
2227 * devices.
2228 *
2229 * Return: 0 on success, negative error code on failure.
2230 */
drm_dp_mst_connector_late_register(struct drm_connector * connector,struct drm_dp_mst_port * port)2231 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2232 struct drm_dp_mst_port *port)
2233 {
2234 drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2235 port->aux.name, connector->kdev->kobj.name);
2236
2237 port->aux.dev = connector->kdev;
2238 return drm_dp_aux_register_devnode(&port->aux);
2239 }
2240 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2241
2242 /**
2243 * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2244 * @connector: The MST connector
2245 * @port: The MST port for this connector
2246 *
2247 * Helper to unregister the remote aux device for this MST port, registered by
2248 * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2249 * connector's early_unregister hook.
2250 */
drm_dp_mst_connector_early_unregister(struct drm_connector * connector,struct drm_dp_mst_port * port)2251 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2252 struct drm_dp_mst_port *port)
2253 {
2254 drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2255 port->aux.name, connector->kdev->kobj.name);
2256 drm_dp_aux_unregister_devnode(&port->aux);
2257 }
2258 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2259
2260 static void
drm_dp_mst_port_add_connector(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port)2261 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2262 struct drm_dp_mst_port *port)
2263 {
2264 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2265 char proppath[255];
2266 int ret;
2267
2268 build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2269 port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2270 if (!port->connector) {
2271 ret = -ENOMEM;
2272 goto error;
2273 }
2274
2275 if (port->pdt != DP_PEER_DEVICE_NONE &&
2276 drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2277 drm_dp_mst_port_is_logical(port))
2278 port->cached_edid = drm_edid_read_ddc(port->connector,
2279 &port->aux.ddc);
2280
2281 drm_connector_register(port->connector);
2282 return;
2283
2284 error:
2285 drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2286 }
2287
2288 /*
2289 * Drop a topology reference, and unlink the port from the in-memory topology
2290 * layout
2291 */
2292 static void
drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)2293 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2294 struct drm_dp_mst_port *port)
2295 {
2296 mutex_lock(&mgr->lock);
2297 port->parent->num_ports--;
2298 list_del(&port->next);
2299 mutex_unlock(&mgr->lock);
2300 drm_dp_mst_topology_put_port(port);
2301 }
2302
2303 static struct drm_dp_mst_port *
drm_dp_mst_add_port(struct drm_device * dev,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,u8 port_number)2304 drm_dp_mst_add_port(struct drm_device *dev,
2305 struct drm_dp_mst_topology_mgr *mgr,
2306 struct drm_dp_mst_branch *mstb, u8 port_number)
2307 {
2308 struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2309
2310 if (!port)
2311 return NULL;
2312
2313 kref_init(&port->topology_kref);
2314 kref_init(&port->malloc_kref);
2315 port->parent = mstb;
2316 port->port_num = port_number;
2317 port->mgr = mgr;
2318 port->aux.name = "DPMST";
2319 port->aux.dev = dev->dev;
2320 port->aux.is_remote = true;
2321
2322 /* initialize the MST downstream port's AUX crc work queue */
2323 port->aux.drm_dev = dev;
2324 drm_dp_remote_aux_init(&port->aux);
2325
2326 /*
2327 * Make sure the memory allocation for our parent branch stays
2328 * around until our own memory allocation is released
2329 */
2330 drm_dp_mst_get_mstb_malloc(mstb);
2331
2332 return port;
2333 }
2334
2335 static int
drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch * mstb,struct drm_device * dev,struct drm_dp_link_addr_reply_port * port_msg)2336 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2337 struct drm_device *dev,
2338 struct drm_dp_link_addr_reply_port *port_msg)
2339 {
2340 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2341 struct drm_dp_mst_port *port;
2342 int old_ddps = 0, ret;
2343 u8 new_pdt = DP_PEER_DEVICE_NONE;
2344 bool new_mcs = 0;
2345 bool created = false, send_link_addr = false, changed = false;
2346
2347 port = drm_dp_get_port(mstb, port_msg->port_number);
2348 if (!port) {
2349 port = drm_dp_mst_add_port(dev, mgr, mstb,
2350 port_msg->port_number);
2351 if (!port)
2352 return -ENOMEM;
2353 created = true;
2354 changed = true;
2355 } else if (!port->input && port_msg->input_port && port->connector) {
2356 /* Since port->connector can't be changed here, we create a
2357 * new port if input_port changes from 0 to 1
2358 */
2359 drm_dp_mst_topology_unlink_port(mgr, port);
2360 drm_dp_mst_topology_put_port(port);
2361 port = drm_dp_mst_add_port(dev, mgr, mstb,
2362 port_msg->port_number);
2363 if (!port)
2364 return -ENOMEM;
2365 changed = true;
2366 created = true;
2367 } else if (port->input && !port_msg->input_port) {
2368 changed = true;
2369 } else if (port->connector) {
2370 /* We're updating a port that's exposed to userspace, so do it
2371 * under lock
2372 */
2373 drm_modeset_lock(&mgr->base.lock, NULL);
2374
2375 old_ddps = port->ddps;
2376 changed = port->ddps != port_msg->ddps ||
2377 (port->ddps &&
2378 (port->ldps != port_msg->legacy_device_plug_status ||
2379 port->dpcd_rev != port_msg->dpcd_revision ||
2380 port->mcs != port_msg->mcs ||
2381 port->pdt != port_msg->peer_device_type ||
2382 port->num_sdp_stream_sinks !=
2383 port_msg->num_sdp_stream_sinks));
2384 }
2385
2386 port->input = port_msg->input_port;
2387 if (!port->input)
2388 new_pdt = port_msg->peer_device_type;
2389 new_mcs = port_msg->mcs;
2390 port->ddps = port_msg->ddps;
2391 port->ldps = port_msg->legacy_device_plug_status;
2392 port->dpcd_rev = port_msg->dpcd_revision;
2393 port->num_sdp_streams = port_msg->num_sdp_streams;
2394 port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2395
2396 /* manage mstb port lists with mgr lock - take a reference
2397 for this list */
2398 if (created) {
2399 mutex_lock(&mgr->lock);
2400 drm_dp_mst_topology_get_port(port);
2401 list_add(&port->next, &mstb->ports);
2402 mstb->num_ports++;
2403 mutex_unlock(&mgr->lock);
2404 }
2405
2406 /*
2407 * Reprobe PBN caps on both hotplug, and when re-probing the link
2408 * for our parent mstb
2409 */
2410 if (old_ddps != port->ddps || !created) {
2411 if (port->ddps && !port->input) {
2412 ret = drm_dp_send_enum_path_resources(mgr, mstb,
2413 port);
2414 if (ret == 1)
2415 changed = true;
2416 } else {
2417 port->full_pbn = 0;
2418 }
2419 }
2420
2421 ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2422 if (ret == 1) {
2423 send_link_addr = true;
2424 } else if (ret < 0) {
2425 drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2426 goto fail;
2427 }
2428
2429 /*
2430 * If this port wasn't just created, then we're reprobing because
2431 * we're coming out of suspend. In this case, always resend the link
2432 * address if there's an MSTB on this port
2433 */
2434 if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2435 port->mcs)
2436 send_link_addr = true;
2437
2438 if (port->connector)
2439 drm_modeset_unlock(&mgr->base.lock);
2440 else if (!port->input)
2441 drm_dp_mst_port_add_connector(mstb, port);
2442
2443 if (send_link_addr && port->mstb) {
2444 ret = drm_dp_send_link_address(mgr, port->mstb);
2445 if (ret == 1) /* MSTB below us changed */
2446 changed = true;
2447 else if (ret < 0)
2448 goto fail_put;
2449 }
2450
2451 /* put reference to this port */
2452 drm_dp_mst_topology_put_port(port);
2453 return changed;
2454
2455 fail:
2456 drm_dp_mst_topology_unlink_port(mgr, port);
2457 if (port->connector)
2458 drm_modeset_unlock(&mgr->base.lock);
2459 fail_put:
2460 drm_dp_mst_topology_put_port(port);
2461 return ret;
2462 }
2463
2464 static int
drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch * mstb,struct drm_dp_connection_status_notify * conn_stat)2465 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2466 struct drm_dp_connection_status_notify *conn_stat)
2467 {
2468 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2469 struct drm_dp_mst_port *port;
2470 int old_ddps, ret;
2471 u8 new_pdt;
2472 bool new_mcs;
2473 bool dowork = false, create_connector = false;
2474
2475 port = drm_dp_get_port(mstb, conn_stat->port_number);
2476 if (!port)
2477 return 0;
2478
2479 if (port->connector) {
2480 if (!port->input && conn_stat->input_port) {
2481 /*
2482 * We can't remove a connector from an already exposed
2483 * port, so just throw the port out and make sure we
2484 * reprobe the link address of it's parent MSTB
2485 */
2486 drm_dp_mst_topology_unlink_port(mgr, port);
2487 mstb->link_address_sent = false;
2488 dowork = true;
2489 goto out;
2490 }
2491
2492 /* Locking is only needed if the port's exposed to userspace */
2493 drm_modeset_lock(&mgr->base.lock, NULL);
2494 } else if (port->input && !conn_stat->input_port) {
2495 create_connector = true;
2496 /* Reprobe link address so we get num_sdp_streams */
2497 mstb->link_address_sent = false;
2498 dowork = true;
2499 }
2500
2501 old_ddps = port->ddps;
2502 port->input = conn_stat->input_port;
2503 port->ldps = conn_stat->legacy_device_plug_status;
2504 port->ddps = conn_stat->displayport_device_plug_status;
2505
2506 if (old_ddps != port->ddps) {
2507 if (port->ddps && !port->input)
2508 drm_dp_send_enum_path_resources(mgr, mstb, port);
2509 else
2510 port->full_pbn = 0;
2511 }
2512
2513 new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2514 new_mcs = conn_stat->message_capability_status;
2515 ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2516 if (ret == 1) {
2517 dowork = true;
2518 } else if (ret < 0) {
2519 drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2520 dowork = false;
2521 }
2522
2523 if (port->connector)
2524 drm_modeset_unlock(&mgr->base.lock);
2525 else if (create_connector)
2526 drm_dp_mst_port_add_connector(mstb, port);
2527
2528 out:
2529 drm_dp_mst_topology_put_port(port);
2530 return dowork;
2531 }
2532
drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr * mgr,u8 lct,u8 * rad)2533 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2534 u8 lct, u8 *rad)
2535 {
2536 struct drm_dp_mst_branch *mstb;
2537 struct drm_dp_mst_port *port;
2538 int i, ret;
2539 /* find the port by iterating down */
2540
2541 mutex_lock(&mgr->lock);
2542 mstb = mgr->mst_primary;
2543
2544 if (!mstb)
2545 goto out;
2546
2547 for (i = 0; i < lct - 1; i++) {
2548 int shift = (i % 2) ? 0 : 4;
2549 int port_num = (rad[i / 2] >> shift) & 0xf;
2550
2551 list_for_each_entry(port, &mstb->ports, next) {
2552 if (port->port_num == port_num) {
2553 mstb = port->mstb;
2554 if (!mstb) {
2555 drm_err(mgr->dev,
2556 "failed to lookup MSTB with lct %d, rad %02x\n",
2557 lct, rad[0]);
2558 goto out;
2559 }
2560
2561 break;
2562 }
2563 }
2564 }
2565 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2566 if (!ret)
2567 mstb = NULL;
2568 out:
2569 mutex_unlock(&mgr->lock);
2570 return mstb;
2571 }
2572
get_mst_branch_device_by_guid_helper(struct drm_dp_mst_branch * mstb,const uint8_t * guid)2573 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2574 struct drm_dp_mst_branch *mstb,
2575 const uint8_t *guid)
2576 {
2577 struct drm_dp_mst_branch *found_mstb;
2578 struct drm_dp_mst_port *port;
2579
2580 if (!mstb)
2581 return NULL;
2582
2583 if (memcmp(mstb->guid, guid, 16) == 0)
2584 return mstb;
2585
2586
2587 list_for_each_entry(port, &mstb->ports, next) {
2588 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2589
2590 if (found_mstb)
2591 return found_mstb;
2592 }
2593
2594 return NULL;
2595 }
2596
2597 static struct drm_dp_mst_branch *
drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr * mgr,const uint8_t * guid)2598 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2599 const uint8_t *guid)
2600 {
2601 struct drm_dp_mst_branch *mstb;
2602 int ret;
2603
2604 /* find the port by iterating down */
2605 mutex_lock(&mgr->lock);
2606
2607 mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2608 if (mstb) {
2609 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2610 if (!ret)
2611 mstb = NULL;
2612 }
2613
2614 mutex_unlock(&mgr->lock);
2615 return mstb;
2616 }
2617
drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)2618 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2619 struct drm_dp_mst_branch *mstb)
2620 {
2621 struct drm_dp_mst_port *port;
2622 int ret;
2623 bool changed = false;
2624
2625 if (!mstb->link_address_sent) {
2626 ret = drm_dp_send_link_address(mgr, mstb);
2627 if (ret == 1)
2628 changed = true;
2629 else if (ret < 0)
2630 return ret;
2631 }
2632
2633 list_for_each_entry(port, &mstb->ports, next) {
2634 if (port->input || !port->ddps || !port->mstb)
2635 continue;
2636
2637 ret = drm_dp_check_and_send_link_address(mgr, port->mstb);
2638 if (ret == 1)
2639 changed = true;
2640 else if (ret < 0)
2641 return ret;
2642 }
2643
2644 return changed;
2645 }
2646
drm_dp_mst_link_probe_work(struct work_struct * work)2647 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2648 {
2649 struct drm_dp_mst_topology_mgr *mgr =
2650 container_of(work, struct drm_dp_mst_topology_mgr, work);
2651 struct drm_device *dev = mgr->dev;
2652 struct drm_dp_mst_branch *mstb;
2653 int ret;
2654 bool clear_payload_id_table;
2655
2656 mutex_lock(&mgr->probe_lock);
2657
2658 mutex_lock(&mgr->lock);
2659 clear_payload_id_table = !mgr->payload_id_table_cleared;
2660 mgr->payload_id_table_cleared = true;
2661
2662 mstb = mgr->mst_primary;
2663 if (mstb) {
2664 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2665 if (!ret)
2666 mstb = NULL;
2667 }
2668 mutex_unlock(&mgr->lock);
2669 if (!mstb) {
2670 mutex_unlock(&mgr->probe_lock);
2671 return;
2672 }
2673
2674 /*
2675 * Certain branch devices seem to incorrectly report an available_pbn
2676 * of 0 on downstream sinks, even after clearing the
2677 * DP_PAYLOAD_ALLOCATE_* registers in
2678 * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2679 * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2680 * things work again.
2681 */
2682 if (clear_payload_id_table) {
2683 drm_dbg_kms(dev, "Clearing payload ID table\n");
2684 drm_dp_send_clear_payload_id_table(mgr, mstb);
2685 }
2686
2687 ret = drm_dp_check_and_send_link_address(mgr, mstb);
2688 drm_dp_mst_topology_put_mstb(mstb);
2689
2690 mutex_unlock(&mgr->probe_lock);
2691 if (ret > 0)
2692 drm_kms_helper_hotplug_event(dev);
2693 }
2694
drm_dp_validate_guid(struct drm_dp_mst_topology_mgr * mgr,u8 * guid)2695 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2696 u8 *guid)
2697 {
2698 u64 salt;
2699
2700 if (memchr_inv(guid, 0, 16))
2701 return true;
2702
2703 salt = get_jiffies_64();
2704
2705 memcpy(&guid[0], &salt, sizeof(u64));
2706 memcpy(&guid[8], &salt, sizeof(u64));
2707
2708 return false;
2709 }
2710
build_dpcd_read(struct drm_dp_sideband_msg_tx * msg,u8 port_num,u32 offset,u8 num_bytes)2711 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2712 u8 port_num, u32 offset, u8 num_bytes)
2713 {
2714 struct drm_dp_sideband_msg_req_body req;
2715
2716 req.req_type = DP_REMOTE_DPCD_READ;
2717 req.u.dpcd_read.port_number = port_num;
2718 req.u.dpcd_read.dpcd_address = offset;
2719 req.u.dpcd_read.num_bytes = num_bytes;
2720 drm_dp_encode_sideband_req(&req, msg);
2721 }
2722
drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr * mgr,bool up,u8 * msg,int len)2723 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2724 bool up, u8 *msg, int len)
2725 {
2726 int ret;
2727 int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2728 int tosend, total, offset;
2729 int retries = 0;
2730
2731 retry:
2732 total = len;
2733 offset = 0;
2734 do {
2735 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2736
2737 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2738 &msg[offset],
2739 tosend);
2740 if (ret != tosend) {
2741 if (ret == -EIO && retries < 5) {
2742 retries++;
2743 goto retry;
2744 }
2745 drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2746
2747 return -EIO;
2748 }
2749 offset += tosend;
2750 total -= tosend;
2751 } while (total > 0);
2752 return 0;
2753 }
2754
set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr * hdr,struct drm_dp_sideband_msg_tx * txmsg)2755 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2756 struct drm_dp_sideband_msg_tx *txmsg)
2757 {
2758 struct drm_dp_mst_branch *mstb = txmsg->dst;
2759 u8 req_type;
2760
2761 req_type = txmsg->msg[0] & 0x7f;
2762 if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2763 req_type == DP_RESOURCE_STATUS_NOTIFY ||
2764 req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2765 hdr->broadcast = 1;
2766 else
2767 hdr->broadcast = 0;
2768 hdr->path_msg = txmsg->path_msg;
2769 if (hdr->broadcast) {
2770 hdr->lct = 1;
2771 hdr->lcr = 6;
2772 } else {
2773 hdr->lct = mstb->lct;
2774 hdr->lcr = mstb->lct - 1;
2775 }
2776
2777 memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2778
2779 return 0;
2780 }
2781 /*
2782 * process a single block of the next message in the sideband queue
2783 */
process_single_tx_qlock(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg,bool up)2784 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2785 struct drm_dp_sideband_msg_tx *txmsg,
2786 bool up)
2787 {
2788 u8 chunk[48];
2789 struct drm_dp_sideband_msg_hdr hdr;
2790 int len, space, idx, tosend;
2791 int ret;
2792
2793 if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2794 return 0;
2795
2796 memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2797
2798 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2799 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2800
2801 /* make hdr from dst mst */
2802 ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2803 if (ret < 0)
2804 return ret;
2805
2806 /* amount left to send in this message */
2807 len = txmsg->cur_len - txmsg->cur_offset;
2808
2809 /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2810 space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2811
2812 tosend = min(len, space);
2813 if (len == txmsg->cur_len)
2814 hdr.somt = 1;
2815 if (space >= len)
2816 hdr.eomt = 1;
2817
2818
2819 hdr.msg_len = tosend + 1;
2820 drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2821 memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2822 /* add crc at end */
2823 drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2824 idx += tosend + 1;
2825
2826 ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2827 if (ret) {
2828 if (drm_debug_enabled(DRM_UT_DP)) {
2829 struct drm_printer p = drm_dbg_printer(mgr->dev,
2830 DRM_UT_DP,
2831 DBG_PREFIX);
2832
2833 drm_printf(&p, "sideband msg failed to send\n");
2834 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2835 }
2836 return ret;
2837 }
2838
2839 txmsg->cur_offset += tosend;
2840 if (txmsg->cur_offset == txmsg->cur_len) {
2841 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2842 return 1;
2843 }
2844 return 0;
2845 }
2846
process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr * mgr)2847 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2848 {
2849 struct drm_dp_sideband_msg_tx *txmsg;
2850 int ret;
2851
2852 WARN_ON(!mutex_is_locked(&mgr->qlock));
2853
2854 /* construct a chunk from the first msg in the tx_msg queue */
2855 if (list_empty(&mgr->tx_msg_downq))
2856 return;
2857
2858 txmsg = list_first_entry(&mgr->tx_msg_downq,
2859 struct drm_dp_sideband_msg_tx, next);
2860 ret = process_single_tx_qlock(mgr, txmsg, false);
2861 if (ret < 0) {
2862 drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2863 list_del(&txmsg->next);
2864 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2865 wake_up_all(&mgr->tx_waitq);
2866 }
2867 }
2868
drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg)2869 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2870 struct drm_dp_sideband_msg_tx *txmsg)
2871 {
2872 mutex_lock(&mgr->qlock);
2873 list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2874
2875 if (drm_debug_enabled(DRM_UT_DP)) {
2876 struct drm_printer p = drm_dbg_printer(mgr->dev, DRM_UT_DP,
2877 DBG_PREFIX);
2878
2879 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2880 }
2881
2882 if (list_is_singular(&mgr->tx_msg_downq))
2883 process_single_down_tx_qlock(mgr);
2884 mutex_unlock(&mgr->qlock);
2885 }
2886
2887 static void
drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_link_address_ack_reply * reply)2888 drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2889 struct drm_dp_link_address_ack_reply *reply)
2890 {
2891 struct drm_dp_link_addr_reply_port *port_reply;
2892 int i;
2893
2894 for (i = 0; i < reply->nports; i++) {
2895 port_reply = &reply->ports[i];
2896 drm_dbg_kms(mgr->dev,
2897 "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2898 i,
2899 port_reply->input_port,
2900 port_reply->peer_device_type,
2901 port_reply->port_number,
2902 port_reply->dpcd_revision,
2903 port_reply->mcs,
2904 port_reply->ddps,
2905 port_reply->legacy_device_plug_status,
2906 port_reply->num_sdp_streams,
2907 port_reply->num_sdp_stream_sinks);
2908 }
2909 }
2910
drm_dp_send_link_address(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)2911 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2912 struct drm_dp_mst_branch *mstb)
2913 {
2914 struct drm_dp_sideband_msg_tx *txmsg;
2915 struct drm_dp_link_address_ack_reply *reply;
2916 struct drm_dp_mst_port *port, *tmp;
2917 int i, ret, port_mask = 0;
2918 bool changed = false;
2919
2920 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2921 if (!txmsg)
2922 return -ENOMEM;
2923
2924 txmsg->dst = mstb;
2925 build_link_address(txmsg);
2926
2927 mstb->link_address_sent = true;
2928 drm_dp_queue_down_tx(mgr, txmsg);
2929
2930 /* FIXME: Actually do some real error handling here */
2931 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2932 if (ret <= 0) {
2933 drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2934 goto out;
2935 }
2936 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2937 drm_err(mgr->dev, "link address NAK received\n");
2938 ret = -EIO;
2939 goto out;
2940 }
2941
2942 reply = &txmsg->reply.u.link_addr;
2943 drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2944 drm_dp_dump_link_address(mgr, reply);
2945
2946 ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2947 if (ret) {
2948 char buf[64];
2949
2950 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2951 drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2952 goto out;
2953 }
2954
2955 for (i = 0; i < reply->nports; i++) {
2956 port_mask |= BIT(reply->ports[i].port_number);
2957 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
2958 &reply->ports[i]);
2959 if (ret == 1)
2960 changed = true;
2961 else if (ret < 0)
2962 goto out;
2963 }
2964
2965 /* Prune any ports that are currently a part of mstb in our in-memory
2966 * topology, but were not seen in this link address. Usually this
2967 * means that they were removed while the topology was out of sync,
2968 * e.g. during suspend/resume
2969 */
2970 mutex_lock(&mgr->lock);
2971 list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
2972 if (port_mask & BIT(port->port_num))
2973 continue;
2974
2975 drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
2976 port->port_num);
2977 list_del(&port->next);
2978 drm_dp_mst_topology_put_port(port);
2979 changed = true;
2980 }
2981 mutex_unlock(&mgr->lock);
2982
2983 out:
2984 if (ret <= 0)
2985 mstb->link_address_sent = false;
2986 kfree(txmsg);
2987 return ret < 0 ? ret : changed;
2988 }
2989
2990 static void
drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)2991 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
2992 struct drm_dp_mst_branch *mstb)
2993 {
2994 struct drm_dp_sideband_msg_tx *txmsg;
2995 int ret;
2996
2997 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2998 if (!txmsg)
2999 return;
3000
3001 txmsg->dst = mstb;
3002 build_clear_payload_id_table(txmsg);
3003
3004 drm_dp_queue_down_tx(mgr, txmsg);
3005
3006 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3007 if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3008 drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3009
3010 kfree(txmsg);
3011 }
3012
3013 static int
drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port)3014 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3015 struct drm_dp_mst_branch *mstb,
3016 struct drm_dp_mst_port *port)
3017 {
3018 struct drm_dp_enum_path_resources_ack_reply *path_res;
3019 struct drm_dp_sideband_msg_tx *txmsg;
3020 int ret;
3021
3022 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3023 if (!txmsg)
3024 return -ENOMEM;
3025
3026 txmsg->dst = mstb;
3027 build_enum_path_resources(txmsg, port->port_num);
3028
3029 drm_dp_queue_down_tx(mgr, txmsg);
3030
3031 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3032 if (ret > 0) {
3033 ret = 0;
3034 path_res = &txmsg->reply.u.path_resources;
3035
3036 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3037 drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3038 } else {
3039 if (port->port_num != path_res->port_number)
3040 DRM_ERROR("got incorrect port in response\n");
3041
3042 drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3043 path_res->port_number,
3044 path_res->full_payload_bw_number,
3045 path_res->avail_payload_bw_number);
3046
3047 /*
3048 * If something changed, make sure we send a
3049 * hotplug
3050 */
3051 if (port->full_pbn != path_res->full_payload_bw_number ||
3052 port->fec_capable != path_res->fec_capable)
3053 ret = 1;
3054
3055 port->full_pbn = path_res->full_payload_bw_number;
3056 port->fec_capable = path_res->fec_capable;
3057 }
3058 }
3059
3060 kfree(txmsg);
3061 return ret;
3062 }
3063
drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch * mstb)3064 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3065 {
3066 if (!mstb->port_parent)
3067 return NULL;
3068
3069 if (mstb->port_parent->mstb != mstb)
3070 return mstb->port_parent;
3071
3072 return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3073 }
3074
3075 /*
3076 * Searches upwards in the topology starting from mstb to try to find the
3077 * closest available parent of mstb that's still connected to the rest of the
3078 * topology. This can be used in order to perform operations like releasing
3079 * payloads, where the branch device which owned the payload may no longer be
3080 * around and thus would require that the payload on the last living relative
3081 * be freed instead.
3082 */
3083 static struct drm_dp_mst_branch *
drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,int * port_num)3084 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3085 struct drm_dp_mst_branch *mstb,
3086 int *port_num)
3087 {
3088 struct drm_dp_mst_branch *rmstb = NULL;
3089 struct drm_dp_mst_port *found_port;
3090
3091 mutex_lock(&mgr->lock);
3092 if (!mgr->mst_primary)
3093 goto out;
3094
3095 do {
3096 found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3097 if (!found_port)
3098 break;
3099
3100 if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3101 rmstb = found_port->parent;
3102 *port_num = found_port->port_num;
3103 } else {
3104 /* Search again, starting from this parent */
3105 mstb = found_port->parent;
3106 }
3107 } while (!rmstb);
3108 out:
3109 mutex_unlock(&mgr->lock);
3110 return rmstb;
3111 }
3112
drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int id,int pbn)3113 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3114 struct drm_dp_mst_port *port,
3115 int id,
3116 int pbn)
3117 {
3118 struct drm_dp_sideband_msg_tx *txmsg;
3119 struct drm_dp_mst_branch *mstb;
3120 int ret, port_num;
3121 u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3122 int i;
3123
3124 port_num = port->port_num;
3125 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3126 if (!mstb) {
3127 mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3128 port->parent,
3129 &port_num);
3130
3131 if (!mstb)
3132 return -EINVAL;
3133 }
3134
3135 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3136 if (!txmsg) {
3137 ret = -ENOMEM;
3138 goto fail_put;
3139 }
3140
3141 for (i = 0; i < port->num_sdp_streams; i++)
3142 sinks[i] = i;
3143
3144 txmsg->dst = mstb;
3145 build_allocate_payload(txmsg, port_num,
3146 id,
3147 pbn, port->num_sdp_streams, sinks);
3148
3149 drm_dp_queue_down_tx(mgr, txmsg);
3150
3151 /*
3152 * FIXME: there is a small chance that between getting the last
3153 * connected mstb and sending the payload message, the last connected
3154 * mstb could also be removed from the topology. In the future, this
3155 * needs to be fixed by restarting the
3156 * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3157 * timeout if the topology is still connected to the system.
3158 */
3159 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3160 if (ret > 0) {
3161 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3162 ret = -EINVAL;
3163 else
3164 ret = 0;
3165 }
3166 kfree(txmsg);
3167 fail_put:
3168 drm_dp_mst_topology_put_mstb(mstb);
3169 return ret;
3170 }
3171
drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,bool power_up)3172 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3173 struct drm_dp_mst_port *port, bool power_up)
3174 {
3175 struct drm_dp_sideband_msg_tx *txmsg;
3176 int ret;
3177
3178 port = drm_dp_mst_topology_get_port_validated(mgr, port);
3179 if (!port)
3180 return -EINVAL;
3181
3182 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3183 if (!txmsg) {
3184 drm_dp_mst_topology_put_port(port);
3185 return -ENOMEM;
3186 }
3187
3188 txmsg->dst = port->parent;
3189 build_power_updown_phy(txmsg, port->port_num, power_up);
3190 drm_dp_queue_down_tx(mgr, txmsg);
3191
3192 ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3193 if (ret > 0) {
3194 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3195 ret = -EINVAL;
3196 else
3197 ret = 0;
3198 }
3199 kfree(txmsg);
3200 drm_dp_mst_topology_put_port(port);
3201
3202 return ret;
3203 }
3204 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3205
drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,struct drm_dp_query_stream_enc_status_ack_reply * status)3206 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3207 struct drm_dp_mst_port *port,
3208 struct drm_dp_query_stream_enc_status_ack_reply *status)
3209 {
3210 struct drm_dp_mst_topology_state *state;
3211 struct drm_dp_mst_atomic_payload *payload;
3212 struct drm_dp_sideband_msg_tx *txmsg;
3213 u8 nonce[7];
3214 int ret;
3215
3216 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3217 if (!txmsg)
3218 return -ENOMEM;
3219
3220 port = drm_dp_mst_topology_get_port_validated(mgr, port);
3221 if (!port) {
3222 ret = -EINVAL;
3223 goto out_get_port;
3224 }
3225
3226 get_random_bytes(nonce, sizeof(nonce));
3227
3228 drm_modeset_lock(&mgr->base.lock, NULL);
3229 state = to_drm_dp_mst_topology_state(mgr->base.state);
3230 payload = drm_atomic_get_mst_payload_state(state, port);
3231
3232 /*
3233 * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3234 * transaction at the MST Branch device directly connected to the
3235 * Source"
3236 */
3237 txmsg->dst = mgr->mst_primary;
3238
3239 build_query_stream_enc_status(txmsg, payload->vcpi, nonce);
3240
3241 drm_dp_queue_down_tx(mgr, txmsg);
3242
3243 ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3244 if (ret < 0) {
3245 goto out;
3246 } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3247 drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3248 ret = -ENXIO;
3249 goto out;
3250 }
3251
3252 ret = 0;
3253 memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3254
3255 out:
3256 drm_modeset_unlock(&mgr->base.lock);
3257 drm_dp_mst_topology_put_port(port);
3258 out_get_port:
3259 kfree(txmsg);
3260 return ret;
3261 }
3262 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3263
drm_dp_create_payload_at_dfp(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_atomic_payload * payload)3264 static int drm_dp_create_payload_at_dfp(struct drm_dp_mst_topology_mgr *mgr,
3265 struct drm_dp_mst_atomic_payload *payload)
3266 {
3267 return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot,
3268 payload->time_slots);
3269 }
3270
drm_dp_create_payload_to_remote(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_atomic_payload * payload)3271 static int drm_dp_create_payload_to_remote(struct drm_dp_mst_topology_mgr *mgr,
3272 struct drm_dp_mst_atomic_payload *payload)
3273 {
3274 int ret;
3275 struct drm_dp_mst_port *port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3276
3277 if (!port)
3278 return -EIO;
3279
3280 ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload->pbn);
3281 drm_dp_mst_topology_put_port(port);
3282 return ret;
3283 }
3284
drm_dp_destroy_payload_at_remote_and_dfp(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_state * mst_state,struct drm_dp_mst_atomic_payload * payload)3285 static void drm_dp_destroy_payload_at_remote_and_dfp(struct drm_dp_mst_topology_mgr *mgr,
3286 struct drm_dp_mst_topology_state *mst_state,
3287 struct drm_dp_mst_atomic_payload *payload)
3288 {
3289 drm_dbg_kms(mgr->dev, "\n");
3290
3291 /* it's okay for these to fail */
3292 if (payload->payload_allocation_status == DRM_DP_MST_PAYLOAD_ALLOCATION_REMOTE) {
3293 drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0);
3294 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_DFP;
3295 }
3296
3297 if (payload->payload_allocation_status == DRM_DP_MST_PAYLOAD_ALLOCATION_DFP)
3298 drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot, 0);
3299 }
3300
3301 /**
3302 * drm_dp_add_payload_part1() - Execute payload update part 1
3303 * @mgr: Manager to use.
3304 * @mst_state: The MST atomic state
3305 * @payload: The payload to write
3306 *
3307 * Determines the starting time slot for the given payload, and programs the VCPI for this payload
3308 * into the DPCD of DPRX. After calling this, the driver should generate ACT and payload packets.
3309 *
3310 * Returns: 0 on success, error code on failure.
3311 */
drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_state * mst_state,struct drm_dp_mst_atomic_payload * payload)3312 int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
3313 struct drm_dp_mst_topology_state *mst_state,
3314 struct drm_dp_mst_atomic_payload *payload)
3315 {
3316 struct drm_dp_mst_port *port;
3317 int ret;
3318
3319 /* Update mst mgr info */
3320 if (mgr->payload_count == 0)
3321 mgr->next_start_slot = mst_state->start_slot;
3322
3323 payload->vc_start_slot = mgr->next_start_slot;
3324
3325 mgr->payload_count++;
3326 mgr->next_start_slot += payload->time_slots;
3327
3328 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_LOCAL;
3329
3330 /* Allocate payload to immediate downstream facing port */
3331 port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3332 if (!port) {
3333 drm_dbg_kms(mgr->dev,
3334 "VCPI %d for port %p not in topology, not creating a payload to remote\n",
3335 payload->vcpi, payload->port);
3336 return -EIO;
3337 }
3338
3339 ret = drm_dp_create_payload_at_dfp(mgr, payload);
3340 if (ret < 0) {
3341 drm_dbg_kms(mgr->dev, "Failed to create MST payload for port %p: %d\n",
3342 payload->port, ret);
3343 goto put_port;
3344 }
3345
3346 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_DFP;
3347
3348 put_port:
3349 drm_dp_mst_topology_put_port(port);
3350
3351 return ret;
3352 }
3353 EXPORT_SYMBOL(drm_dp_add_payload_part1);
3354
3355 /**
3356 * drm_dp_remove_payload_part1() - Remove an MST payload along the virtual channel
3357 * @mgr: Manager to use.
3358 * @mst_state: The MST atomic state
3359 * @payload: The payload to remove
3360 *
3361 * Removes a payload along the virtual channel if it was successfully allocated.
3362 * After calling this, the driver should set HW to generate ACT and then switch to new
3363 * payload allocation state.
3364 */
drm_dp_remove_payload_part1(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_state * mst_state,struct drm_dp_mst_atomic_payload * payload)3365 void drm_dp_remove_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
3366 struct drm_dp_mst_topology_state *mst_state,
3367 struct drm_dp_mst_atomic_payload *payload)
3368 {
3369 /* Remove remote payload allocation */
3370 bool send_remove = false;
3371
3372 mutex_lock(&mgr->lock);
3373 send_remove = drm_dp_mst_port_downstream_of_branch(payload->port, mgr->mst_primary);
3374 mutex_unlock(&mgr->lock);
3375
3376 if (send_remove)
3377 drm_dp_destroy_payload_at_remote_and_dfp(mgr, mst_state, payload);
3378 else
3379 drm_dbg_kms(mgr->dev, "Payload for VCPI %d not in topology, not sending remove\n",
3380 payload->vcpi);
3381
3382 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_LOCAL;
3383 }
3384 EXPORT_SYMBOL(drm_dp_remove_payload_part1);
3385
3386 /**
3387 * drm_dp_remove_payload_part2() - Remove an MST payload locally
3388 * @mgr: Manager to use.
3389 * @mst_state: The MST atomic state
3390 * @old_payload: The payload with its old state
3391 * @new_payload: The payload with its latest state
3392 *
3393 * Updates the starting time slots of all other payloads which would have been shifted towards
3394 * the start of the payload ID table as a result of removing a payload. Driver should call this
3395 * function whenever it removes a payload in its HW. It's independent to the result of payload
3396 * allocation/deallocation at branch devices along the virtual channel.
3397 */
drm_dp_remove_payload_part2(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_state * mst_state,const struct drm_dp_mst_atomic_payload * old_payload,struct drm_dp_mst_atomic_payload * new_payload)3398 void drm_dp_remove_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
3399 struct drm_dp_mst_topology_state *mst_state,
3400 const struct drm_dp_mst_atomic_payload *old_payload,
3401 struct drm_dp_mst_atomic_payload *new_payload)
3402 {
3403 struct drm_dp_mst_atomic_payload *pos;
3404
3405 /* Remove local payload allocation */
3406 list_for_each_entry(pos, &mst_state->payloads, next) {
3407 if (pos != new_payload && pos->vc_start_slot > new_payload->vc_start_slot)
3408 pos->vc_start_slot -= old_payload->time_slots;
3409 }
3410 new_payload->vc_start_slot = -1;
3411
3412 mgr->payload_count--;
3413 mgr->next_start_slot -= old_payload->time_slots;
3414
3415 if (new_payload->delete)
3416 drm_dp_mst_put_port_malloc(new_payload->port);
3417
3418 new_payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_NONE;
3419 }
3420 EXPORT_SYMBOL(drm_dp_remove_payload_part2);
3421 /**
3422 * drm_dp_add_payload_part2() - Execute payload update part 2
3423 * @mgr: Manager to use.
3424 * @payload: The payload to update
3425 *
3426 * If @payload was successfully assigned a starting time slot by drm_dp_add_payload_part1(), this
3427 * function will send the sideband messages to finish allocating this payload.
3428 *
3429 * Returns: 0 on success, negative error code on failure.
3430 */
drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_atomic_payload * payload)3431 int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
3432 struct drm_dp_mst_atomic_payload *payload)
3433 {
3434 int ret = 0;
3435
3436 /* Skip failed payloads */
3437 if (payload->payload_allocation_status != DRM_DP_MST_PAYLOAD_ALLOCATION_DFP) {
3438 drm_dbg_kms(mgr->dev, "Part 1 of payload creation for %s failed, skipping part 2\n",
3439 payload->port->connector->name);
3440 return -EIO;
3441 }
3442
3443 /* Allocate payload to remote end */
3444 ret = drm_dp_create_payload_to_remote(mgr, payload);
3445 if (ret < 0)
3446 drm_err(mgr->dev, "Step 2 of creating MST payload for %p failed: %d\n",
3447 payload->port, ret);
3448 else
3449 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_REMOTE;
3450
3451 return ret;
3452 }
3453 EXPORT_SYMBOL(drm_dp_add_payload_part2);
3454
drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int offset,int size,u8 * bytes)3455 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3456 struct drm_dp_mst_port *port,
3457 int offset, int size, u8 *bytes)
3458 {
3459 int ret = 0;
3460 struct drm_dp_sideband_msg_tx *txmsg;
3461 struct drm_dp_mst_branch *mstb;
3462
3463 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3464 if (!mstb)
3465 return -EINVAL;
3466
3467 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3468 if (!txmsg) {
3469 ret = -ENOMEM;
3470 goto fail_put;
3471 }
3472
3473 build_dpcd_read(txmsg, port->port_num, offset, size);
3474 txmsg->dst = port->parent;
3475
3476 drm_dp_queue_down_tx(mgr, txmsg);
3477
3478 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3479 if (ret < 0)
3480 goto fail_free;
3481
3482 if (txmsg->reply.reply_type == 1) {
3483 drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3484 mstb, port->port_num, offset, size);
3485 ret = -EIO;
3486 goto fail_free;
3487 }
3488
3489 if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3490 ret = -EPROTO;
3491 goto fail_free;
3492 }
3493
3494 ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3495 size);
3496 memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3497
3498 fail_free:
3499 kfree(txmsg);
3500 fail_put:
3501 drm_dp_mst_topology_put_mstb(mstb);
3502
3503 return ret;
3504 }
3505
drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int offset,int size,u8 * bytes)3506 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3507 struct drm_dp_mst_port *port,
3508 int offset, int size, u8 *bytes)
3509 {
3510 int ret;
3511 struct drm_dp_sideband_msg_tx *txmsg;
3512 struct drm_dp_mst_branch *mstb;
3513
3514 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3515 if (!mstb)
3516 return -EINVAL;
3517
3518 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3519 if (!txmsg) {
3520 ret = -ENOMEM;
3521 goto fail_put;
3522 }
3523
3524 build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3525 txmsg->dst = mstb;
3526
3527 drm_dp_queue_down_tx(mgr, txmsg);
3528
3529 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3530 if (ret > 0) {
3531 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3532 ret = -EIO;
3533 else
3534 ret = size;
3535 }
3536
3537 kfree(txmsg);
3538 fail_put:
3539 drm_dp_mst_topology_put_mstb(mstb);
3540 return ret;
3541 }
3542
drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx * msg,u8 req_type)3543 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3544 {
3545 struct drm_dp_sideband_msg_reply_body reply;
3546
3547 reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3548 reply.req_type = req_type;
3549 drm_dp_encode_sideband_reply(&reply, msg);
3550 return 0;
3551 }
3552
drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,int req_type,bool broadcast)3553 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3554 struct drm_dp_mst_branch *mstb,
3555 int req_type, bool broadcast)
3556 {
3557 struct drm_dp_sideband_msg_tx *txmsg;
3558
3559 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3560 if (!txmsg)
3561 return -ENOMEM;
3562
3563 txmsg->dst = mstb;
3564 drm_dp_encode_up_ack_reply(txmsg, req_type);
3565
3566 mutex_lock(&mgr->qlock);
3567 /* construct a chunk from the first msg in the tx_msg queue */
3568 process_single_tx_qlock(mgr, txmsg, true);
3569 mutex_unlock(&mgr->qlock);
3570
3571 kfree(txmsg);
3572 return 0;
3573 }
3574
3575 /**
3576 * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3577 * @mgr: The &drm_dp_mst_topology_mgr to use
3578 * @link_rate: link rate in 10kbits/s units
3579 * @link_lane_count: lane count
3580 *
3581 * Calculate the total bandwidth of a MultiStream Transport link. The returned
3582 * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3583 * convert the number of PBNs required for a given stream to the number of
3584 * timeslots this stream requires in each MTP.
3585 *
3586 * Returns the BW / timeslot value in 20.12 fixed point format.
3587 */
drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr * mgr,int link_rate,int link_lane_count)3588 fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3589 int link_rate, int link_lane_count)
3590 {
3591 int ch_coding_efficiency =
3592 drm_dp_bw_channel_coding_efficiency(drm_dp_is_uhbr_rate(link_rate));
3593 fixed20_12 ret;
3594
3595 if (link_rate == 0 || link_lane_count == 0)
3596 drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3597 link_rate, link_lane_count);
3598
3599 /* See DP v2.0 2.6.4.2, 2.7.6.3 VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3600 ret.full = DIV_ROUND_DOWN_ULL(mul_u32_u32(link_rate * link_lane_count,
3601 ch_coding_efficiency),
3602 (1000000ULL * 8 * 5400) >> 12);
3603
3604 return ret;
3605 }
3606 EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3607
3608 /**
3609 * drm_dp_read_mst_cap() - Read the sink's MST mode capability
3610 * @aux: The DP AUX channel to use
3611 * @dpcd: A cached copy of the DPCD capabilities for this sink
3612 *
3613 * Returns: enum drm_dp_mst_mode to indicate MST mode capability
3614 */
drm_dp_read_mst_cap(struct drm_dp_aux * aux,const u8 dpcd[DP_RECEIVER_CAP_SIZE])3615 enum drm_dp_mst_mode drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3616 const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3617 {
3618 u8 mstm_cap;
3619
3620 if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3621 return DRM_DP_SST;
3622
3623 if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3624 return DRM_DP_SST;
3625
3626 if (mstm_cap & DP_MST_CAP)
3627 return DRM_DP_MST;
3628
3629 if (mstm_cap & DP_SINGLE_STREAM_SIDEBAND_MSG)
3630 return DRM_DP_SST_SIDEBAND_MSG;
3631
3632 return DRM_DP_SST;
3633 }
3634 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3635
3636 /**
3637 * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3638 * @mgr: manager to set state for
3639 * @mst_state: true to enable MST on this connector - false to disable.
3640 *
3641 * This is called by the driver when it detects an MST capable device plugged
3642 * into a DP MST capable port, or when a DP MST capable device is unplugged.
3643 */
drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr * mgr,bool mst_state)3644 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3645 {
3646 int ret = 0;
3647 struct drm_dp_mst_branch *mstb = NULL;
3648
3649 mutex_lock(&mgr->lock);
3650 if (mst_state == mgr->mst_state)
3651 goto out_unlock;
3652
3653 mgr->mst_state = mst_state;
3654 /* set the device into MST mode */
3655 if (mst_state) {
3656 WARN_ON(mgr->mst_primary);
3657
3658 /* get dpcd info */
3659 ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3660 if (ret < 0) {
3661 drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3662 mgr->aux->name, ret);
3663 goto out_unlock;
3664 }
3665
3666 /* add initial branch device at LCT 1 */
3667 mstb = drm_dp_add_mst_branch_device(1, NULL);
3668 if (mstb == NULL) {
3669 ret = -ENOMEM;
3670 goto out_unlock;
3671 }
3672 mstb->mgr = mgr;
3673
3674 /* give this the main reference */
3675 mgr->mst_primary = mstb;
3676 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3677
3678 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3679 DP_MST_EN |
3680 DP_UP_REQ_EN |
3681 DP_UPSTREAM_IS_SRC);
3682 if (ret < 0)
3683 goto out_unlock;
3684
3685 /* Write reset payload */
3686 drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
3687
3688 queue_work(system_long_wq, &mgr->work);
3689
3690 ret = 0;
3691 } else {
3692 /* disable MST on the device */
3693 mstb = mgr->mst_primary;
3694 mgr->mst_primary = NULL;
3695 /* this can fail if the device is gone */
3696 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3697 ret = 0;
3698 mgr->payload_id_table_cleared = false;
3699
3700 memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv));
3701 memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv));
3702 }
3703
3704 out_unlock:
3705 mutex_unlock(&mgr->lock);
3706 if (mstb)
3707 drm_dp_mst_topology_put_mstb(mstb);
3708 return ret;
3709
3710 }
3711 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3712
3713 static void
drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch * mstb)3714 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3715 {
3716 struct drm_dp_mst_port *port;
3717
3718 /* The link address will need to be re-sent on resume */
3719 mstb->link_address_sent = false;
3720
3721 list_for_each_entry(port, &mstb->ports, next)
3722 if (port->mstb)
3723 drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3724 }
3725
3726 /**
3727 * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3728 * @mgr: manager to suspend
3729 *
3730 * This function tells the MST device that we can't handle UP messages
3731 * anymore. This should stop it from sending any since we are suspended.
3732 */
drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr * mgr)3733 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3734 {
3735 mutex_lock(&mgr->lock);
3736 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3737 DP_MST_EN | DP_UPSTREAM_IS_SRC);
3738 mutex_unlock(&mgr->lock);
3739 flush_work(&mgr->up_req_work);
3740 flush_work(&mgr->work);
3741 flush_work(&mgr->delayed_destroy_work);
3742
3743 mutex_lock(&mgr->lock);
3744 if (mgr->mst_state && mgr->mst_primary)
3745 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3746 mutex_unlock(&mgr->lock);
3747 }
3748 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3749
3750 /**
3751 * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3752 * @mgr: manager to resume
3753 * @sync: whether or not to perform topology reprobing synchronously
3754 *
3755 * This will fetch DPCD and see if the device is still there,
3756 * if it is, it will rewrite the MSTM control bits, and return.
3757 *
3758 * If the device fails this returns -1, and the driver should do
3759 * a full MST reprobe, in case we were undocked.
3760 *
3761 * During system resume (where it is assumed that the driver will be calling
3762 * drm_atomic_helper_resume()) this function should be called beforehand with
3763 * @sync set to true. In contexts like runtime resume where the driver is not
3764 * expected to be calling drm_atomic_helper_resume(), this function should be
3765 * called with @sync set to false in order to avoid deadlocking.
3766 *
3767 * Returns: -1 if the MST topology was removed while we were suspended, 0
3768 * otherwise.
3769 */
drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr * mgr,bool sync)3770 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3771 bool sync)
3772 {
3773 int ret;
3774 u8 guid[16];
3775
3776 mutex_lock(&mgr->lock);
3777 if (!mgr->mst_primary)
3778 goto out_fail;
3779
3780 if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
3781 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3782 goto out_fail;
3783 }
3784
3785 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3786 DP_MST_EN |
3787 DP_UP_REQ_EN |
3788 DP_UPSTREAM_IS_SRC);
3789 if (ret < 0) {
3790 drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3791 goto out_fail;
3792 }
3793
3794 /* Some hubs forget their guids after they resume */
3795 ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3796 if (ret != 16) {
3797 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3798 goto out_fail;
3799 }
3800
3801 ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3802 if (ret) {
3803 drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3804 goto out_fail;
3805 }
3806
3807 /*
3808 * For the final step of resuming the topology, we need to bring the
3809 * state of our in-memory topology back into sync with reality. So,
3810 * restart the probing process as if we're probing a new hub
3811 */
3812 queue_work(system_long_wq, &mgr->work);
3813 mutex_unlock(&mgr->lock);
3814
3815 if (sync) {
3816 drm_dbg_kms(mgr->dev,
3817 "Waiting for link probe work to finish re-syncing topology...\n");
3818 flush_work(&mgr->work);
3819 }
3820
3821 return 0;
3822
3823 out_fail:
3824 mutex_unlock(&mgr->lock);
3825 return -1;
3826 }
3827 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3828
3829 static bool
drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr * mgr,bool up,struct drm_dp_mst_branch ** mstb)3830 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3831 struct drm_dp_mst_branch **mstb)
3832 {
3833 int len;
3834 u8 replyblock[32];
3835 int replylen, curreply;
3836 int ret;
3837 u8 hdrlen;
3838 struct drm_dp_sideband_msg_hdr hdr;
3839 struct drm_dp_sideband_msg_rx *msg =
3840 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3841 int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3842 DP_SIDEBAND_MSG_DOWN_REP_BASE;
3843
3844 if (!up)
3845 *mstb = NULL;
3846
3847 len = min(mgr->max_dpcd_transaction_bytes, 16);
3848 ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3849 if (ret != len) {
3850 drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3851 return false;
3852 }
3853
3854 ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3855 if (ret == false) {
3856 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3857 1, replyblock, len, false);
3858 drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3859 return false;
3860 }
3861
3862 if (!up) {
3863 /* Caller is responsible for giving back this reference */
3864 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3865 if (!*mstb) {
3866 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3867 return false;
3868 }
3869 }
3870
3871 if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3872 drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3873 return false;
3874 }
3875
3876 replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3877 ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3878 if (!ret) {
3879 drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3880 return false;
3881 }
3882
3883 replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3884 curreply = len;
3885 while (replylen > 0) {
3886 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3887 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3888 replyblock, len);
3889 if (ret != len) {
3890 drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3891 len, ret);
3892 return false;
3893 }
3894
3895 ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3896 if (!ret) {
3897 drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3898 return false;
3899 }
3900
3901 curreply += len;
3902 replylen -= len;
3903 }
3904 return true;
3905 }
3906
drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr * mgr)3907 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3908 {
3909 struct drm_dp_sideband_msg_tx *txmsg;
3910 struct drm_dp_mst_branch *mstb = NULL;
3911 struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3912
3913 if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3914 goto out_clear_reply;
3915
3916 /* Multi-packet message transmission, don't clear the reply */
3917 if (!msg->have_eomt)
3918 goto out;
3919
3920 /* find the message */
3921 mutex_lock(&mgr->qlock);
3922 txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3923 struct drm_dp_sideband_msg_tx, next);
3924 mutex_unlock(&mgr->qlock);
3925
3926 /* Were we actually expecting a response, and from this mstb? */
3927 if (!txmsg || txmsg->dst != mstb) {
3928 struct drm_dp_sideband_msg_hdr *hdr;
3929
3930 hdr = &msg->initial_hdr;
3931 drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
3932 mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
3933 goto out_clear_reply;
3934 }
3935
3936 drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
3937
3938 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3939 drm_dbg_kms(mgr->dev,
3940 "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
3941 txmsg->reply.req_type,
3942 drm_dp_mst_req_type_str(txmsg->reply.req_type),
3943 txmsg->reply.u.nak.reason,
3944 drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
3945 txmsg->reply.u.nak.nak_data);
3946 }
3947
3948 memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3949 drm_dp_mst_topology_put_mstb(mstb);
3950
3951 mutex_lock(&mgr->qlock);
3952 txmsg->state = DRM_DP_SIDEBAND_TX_RX;
3953 list_del(&txmsg->next);
3954 mutex_unlock(&mgr->qlock);
3955
3956 wake_up_all(&mgr->tx_waitq);
3957
3958 return 0;
3959
3960 out_clear_reply:
3961 memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3962 out:
3963 if (mstb)
3964 drm_dp_mst_topology_put_mstb(mstb);
3965
3966 return 0;
3967 }
3968
3969 static inline bool
drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_pending_up_req * up_req)3970 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
3971 struct drm_dp_pending_up_req *up_req)
3972 {
3973 struct drm_dp_mst_branch *mstb = NULL;
3974 struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
3975 struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
3976 bool hotplug = false, dowork = false;
3977
3978 if (hdr->broadcast) {
3979 const u8 *guid = NULL;
3980
3981 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
3982 guid = msg->u.conn_stat.guid;
3983 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
3984 guid = msg->u.resource_stat.guid;
3985
3986 if (guid)
3987 mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
3988 } else {
3989 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
3990 }
3991
3992 if (!mstb) {
3993 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
3994 return false;
3995 }
3996
3997 /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
3998 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
3999 dowork = drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
4000 hotplug = true;
4001 }
4002
4003 drm_dp_mst_topology_put_mstb(mstb);
4004
4005 if (dowork)
4006 queue_work(system_long_wq, &mgr->work);
4007 return hotplug;
4008 }
4009
drm_dp_mst_up_req_work(struct work_struct * work)4010 static void drm_dp_mst_up_req_work(struct work_struct *work)
4011 {
4012 struct drm_dp_mst_topology_mgr *mgr =
4013 container_of(work, struct drm_dp_mst_topology_mgr,
4014 up_req_work);
4015 struct drm_dp_pending_up_req *up_req;
4016 bool send_hotplug = false;
4017
4018 mutex_lock(&mgr->probe_lock);
4019 while (true) {
4020 mutex_lock(&mgr->up_req_lock);
4021 up_req = list_first_entry_or_null(&mgr->up_req_list,
4022 struct drm_dp_pending_up_req,
4023 next);
4024 if (up_req)
4025 list_del(&up_req->next);
4026 mutex_unlock(&mgr->up_req_lock);
4027
4028 if (!up_req)
4029 break;
4030
4031 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4032 kfree(up_req);
4033 }
4034 mutex_unlock(&mgr->probe_lock);
4035
4036 if (send_hotplug)
4037 drm_kms_helper_hotplug_event(mgr->dev);
4038 }
4039
drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr * mgr)4040 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4041 {
4042 struct drm_dp_pending_up_req *up_req;
4043
4044 if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4045 goto out;
4046
4047 if (!mgr->up_req_recv.have_eomt)
4048 return 0;
4049
4050 up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4051 if (!up_req)
4052 return -ENOMEM;
4053
4054 INIT_LIST_HEAD(&up_req->next);
4055
4056 drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4057
4058 if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4059 up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4060 drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4061 up_req->msg.req_type);
4062 kfree(up_req);
4063 goto out;
4064 }
4065
4066 drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4067 false);
4068
4069 if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4070 const struct drm_dp_connection_status_notify *conn_stat =
4071 &up_req->msg.u.conn_stat;
4072
4073 drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4074 conn_stat->port_number,
4075 conn_stat->legacy_device_plug_status,
4076 conn_stat->displayport_device_plug_status,
4077 conn_stat->message_capability_status,
4078 conn_stat->input_port,
4079 conn_stat->peer_device_type);
4080 } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4081 const struct drm_dp_resource_status_notify *res_stat =
4082 &up_req->msg.u.resource_stat;
4083
4084 drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4085 res_stat->port_number,
4086 res_stat->available_pbn);
4087 }
4088
4089 up_req->hdr = mgr->up_req_recv.initial_hdr;
4090 mutex_lock(&mgr->up_req_lock);
4091 list_add_tail(&up_req->next, &mgr->up_req_list);
4092 mutex_unlock(&mgr->up_req_lock);
4093 queue_work(system_long_wq, &mgr->up_req_work);
4094
4095 out:
4096 memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4097 return 0;
4098 }
4099
4100 /**
4101 * drm_dp_mst_hpd_irq_handle_event() - MST hotplug IRQ handle MST event
4102 * @mgr: manager to notify irq for.
4103 * @esi: 4 bytes from SINK_COUNT_ESI
4104 * @ack: 4 bytes used to ack events starting from SINK_COUNT_ESI
4105 * @handled: whether the hpd interrupt was consumed or not
4106 *
4107 * This should be called from the driver when it detects a HPD IRQ,
4108 * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4109 * topology manager will process the sideband messages received
4110 * as indicated in the DEVICE_SERVICE_IRQ_VECTOR_ESI0 and set the
4111 * corresponding flags that Driver has to ack the DP receiver later.
4112 *
4113 * Note that driver shall also call
4114 * drm_dp_mst_hpd_irq_send_new_request() if the 'handled' is set
4115 * after calling this function, to try to kick off a new request in
4116 * the queue if the previous message transaction is completed.
4117 *
4118 * See also:
4119 * drm_dp_mst_hpd_irq_send_new_request()
4120 */
drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr * mgr,const u8 * esi,u8 * ack,bool * handled)4121 int drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr *mgr, const u8 *esi,
4122 u8 *ack, bool *handled)
4123 {
4124 int ret = 0;
4125 int sc;
4126 *handled = false;
4127 sc = DP_GET_SINK_COUNT(esi[0]);
4128
4129 if (sc != mgr->sink_count) {
4130 mgr->sink_count = sc;
4131 *handled = true;
4132 }
4133
4134 if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4135 ret = drm_dp_mst_handle_down_rep(mgr);
4136 *handled = true;
4137 ack[1] |= DP_DOWN_REP_MSG_RDY;
4138 }
4139
4140 if (esi[1] & DP_UP_REQ_MSG_RDY) {
4141 ret |= drm_dp_mst_handle_up_req(mgr);
4142 *handled = true;
4143 ack[1] |= DP_UP_REQ_MSG_RDY;
4144 }
4145
4146 return ret;
4147 }
4148 EXPORT_SYMBOL(drm_dp_mst_hpd_irq_handle_event);
4149
4150 /**
4151 * drm_dp_mst_hpd_irq_send_new_request() - MST hotplug IRQ kick off new request
4152 * @mgr: manager to notify irq for.
4153 *
4154 * This should be called from the driver when mst irq event is handled
4155 * and acked. Note that new down request should only be sent when
4156 * previous message transaction is completed. Source is not supposed to generate
4157 * interleaved message transactions.
4158 */
drm_dp_mst_hpd_irq_send_new_request(struct drm_dp_mst_topology_mgr * mgr)4159 void drm_dp_mst_hpd_irq_send_new_request(struct drm_dp_mst_topology_mgr *mgr)
4160 {
4161 struct drm_dp_sideband_msg_tx *txmsg;
4162 bool kick = true;
4163
4164 mutex_lock(&mgr->qlock);
4165 txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
4166 struct drm_dp_sideband_msg_tx, next);
4167 /* If last transaction is not completed yet*/
4168 if (!txmsg ||
4169 txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
4170 txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
4171 kick = false;
4172 mutex_unlock(&mgr->qlock);
4173
4174 if (kick)
4175 drm_dp_mst_kick_tx(mgr);
4176 }
4177 EXPORT_SYMBOL(drm_dp_mst_hpd_irq_send_new_request);
4178 /**
4179 * drm_dp_mst_detect_port() - get connection status for an MST port
4180 * @connector: DRM connector for this port
4181 * @ctx: The acquisition context to use for grabbing locks
4182 * @mgr: manager for this port
4183 * @port: pointer to a port
4184 *
4185 * This returns the current connection state for a port.
4186 */
4187 int
drm_dp_mst_detect_port(struct drm_connector * connector,struct drm_modeset_acquire_ctx * ctx,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4188 drm_dp_mst_detect_port(struct drm_connector *connector,
4189 struct drm_modeset_acquire_ctx *ctx,
4190 struct drm_dp_mst_topology_mgr *mgr,
4191 struct drm_dp_mst_port *port)
4192 {
4193 int ret;
4194
4195 /* we need to search for the port in the mgr in case it's gone */
4196 port = drm_dp_mst_topology_get_port_validated(mgr, port);
4197 if (!port)
4198 return connector_status_disconnected;
4199
4200 ret = drm_modeset_lock(&mgr->base.lock, ctx);
4201 if (ret)
4202 goto out;
4203
4204 ret = connector_status_disconnected;
4205
4206 if (!port->ddps)
4207 goto out;
4208
4209 switch (port->pdt) {
4210 case DP_PEER_DEVICE_NONE:
4211 break;
4212 case DP_PEER_DEVICE_MST_BRANCHING:
4213 if (!port->mcs)
4214 ret = connector_status_connected;
4215 break;
4216
4217 case DP_PEER_DEVICE_SST_SINK:
4218 ret = connector_status_connected;
4219 /* for logical ports - cache the EDID */
4220 if (drm_dp_mst_port_is_logical(port) && !port->cached_edid)
4221 port->cached_edid = drm_edid_read_ddc(connector, &port->aux.ddc);
4222 break;
4223 case DP_PEER_DEVICE_DP_LEGACY_CONV:
4224 if (port->ldps)
4225 ret = connector_status_connected;
4226 break;
4227 }
4228 out:
4229 drm_dp_mst_topology_put_port(port);
4230 return ret;
4231 }
4232 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4233
4234 /**
4235 * drm_dp_mst_edid_read() - get EDID for an MST port
4236 * @connector: toplevel connector to get EDID for
4237 * @mgr: manager for this port
4238 * @port: unverified pointer to a port.
4239 *
4240 * This returns an EDID for the port connected to a connector,
4241 * It validates the pointer still exists so the caller doesn't require a
4242 * reference.
4243 */
drm_dp_mst_edid_read(struct drm_connector * connector,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4244 const struct drm_edid *drm_dp_mst_edid_read(struct drm_connector *connector,
4245 struct drm_dp_mst_topology_mgr *mgr,
4246 struct drm_dp_mst_port *port)
4247 {
4248 const struct drm_edid *drm_edid;
4249
4250 /* we need to search for the port in the mgr in case it's gone */
4251 port = drm_dp_mst_topology_get_port_validated(mgr, port);
4252 if (!port)
4253 return NULL;
4254
4255 if (port->cached_edid)
4256 drm_edid = drm_edid_dup(port->cached_edid);
4257 else
4258 drm_edid = drm_edid_read_ddc(connector, &port->aux.ddc);
4259
4260 drm_dp_mst_topology_put_port(port);
4261
4262 return drm_edid;
4263 }
4264 EXPORT_SYMBOL(drm_dp_mst_edid_read);
4265
4266 /**
4267 * drm_dp_mst_get_edid() - get EDID for an MST port
4268 * @connector: toplevel connector to get EDID for
4269 * @mgr: manager for this port
4270 * @port: unverified pointer to a port.
4271 *
4272 * This function is deprecated; please use drm_dp_mst_edid_read() instead.
4273 *
4274 * This returns an EDID for the port connected to a connector,
4275 * It validates the pointer still exists so the caller doesn't require a
4276 * reference.
4277 */
drm_dp_mst_get_edid(struct drm_connector * connector,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4278 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector,
4279 struct drm_dp_mst_topology_mgr *mgr,
4280 struct drm_dp_mst_port *port)
4281 {
4282 const struct drm_edid *drm_edid;
4283 struct edid *edid;
4284
4285 drm_edid = drm_dp_mst_edid_read(connector, mgr, port);
4286
4287 edid = drm_edid_duplicate(drm_edid_raw(drm_edid));
4288
4289 drm_edid_free(drm_edid);
4290
4291 return edid;
4292 }
4293 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4294
4295 /**
4296 * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
4297 * @state: global atomic state
4298 * @mgr: MST topology manager for the port
4299 * @port: port to find time slots for
4300 * @pbn: bandwidth required for the mode in PBN
4301 *
4302 * Allocates time slots to @port, replacing any previous time slot allocations it may
4303 * have had. Any atomic drivers which support MST must call this function in
4304 * their &drm_encoder_helper_funcs.atomic_check() callback unconditionally to
4305 * change the current time slot allocation for the new state, and ensure the MST
4306 * atomic state is added whenever the state of payloads in the topology changes.
4307 *
4308 * Allocations set by this function are not checked against the bandwidth
4309 * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4310 *
4311 * Additionally, it is OK to call this function multiple times on the same
4312 * @port as needed. It is not OK however, to call this function and
4313 * drm_dp_atomic_release_time_slots() in the same atomic check phase.
4314 *
4315 * See also:
4316 * drm_dp_atomic_release_time_slots()
4317 * drm_dp_mst_atomic_check()
4318 *
4319 * Returns:
4320 * Total slots in the atomic state assigned for this port, or a negative error
4321 * code if the port no longer exists
4322 */
drm_dp_atomic_find_time_slots(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int pbn)4323 int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
4324 struct drm_dp_mst_topology_mgr *mgr,
4325 struct drm_dp_mst_port *port, int pbn)
4326 {
4327 struct drm_dp_mst_topology_state *topology_state;
4328 struct drm_dp_mst_atomic_payload *payload = NULL;
4329 struct drm_connector_state *conn_state;
4330 int prev_slots = 0, prev_bw = 0, req_slots;
4331
4332 topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4333 if (IS_ERR(topology_state))
4334 return PTR_ERR(topology_state);
4335
4336 conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4337 topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
4338
4339 /* Find the current allocation for this port, if any */
4340 payload = drm_atomic_get_mst_payload_state(topology_state, port);
4341 if (payload) {
4342 prev_slots = payload->time_slots;
4343 prev_bw = payload->pbn;
4344
4345 /*
4346 * This should never happen, unless the driver tries
4347 * releasing and allocating the same timeslot allocation,
4348 * which is an error
4349 */
4350 if (drm_WARN_ON(mgr->dev, payload->delete)) {
4351 drm_err(mgr->dev,
4352 "cannot allocate and release time slots on [MST PORT:%p] in the same state\n",
4353 port);
4354 return -EINVAL;
4355 }
4356 }
4357
4358 req_slots = DIV_ROUND_UP(dfixed_const(pbn), topology_state->pbn_div.full);
4359
4360 drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n",
4361 port->connector->base.id, port->connector->name,
4362 port, prev_slots, req_slots);
4363 drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4364 port->connector->base.id, port->connector->name,
4365 port, prev_bw, pbn);
4366
4367 /* Add the new allocation to the state, note the VCPI isn't assigned until the end */
4368 if (!payload) {
4369 payload = kzalloc(sizeof(*payload), GFP_KERNEL);
4370 if (!payload)
4371 return -ENOMEM;
4372
4373 drm_dp_mst_get_port_malloc(port);
4374 payload->port = port;
4375 payload->vc_start_slot = -1;
4376 payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_NONE;
4377 list_add(&payload->next, &topology_state->payloads);
4378 }
4379 payload->time_slots = req_slots;
4380 payload->pbn = pbn;
4381
4382 return req_slots;
4383 }
4384 EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
4385
4386 /**
4387 * drm_dp_atomic_release_time_slots() - Release allocated time slots
4388 * @state: global atomic state
4389 * @mgr: MST topology manager for the port
4390 * @port: The port to release the time slots from
4391 *
4392 * Releases any time slots that have been allocated to a port in the atomic
4393 * state. Any atomic drivers which support MST must call this function
4394 * unconditionally in their &drm_connector_helper_funcs.atomic_check() callback.
4395 * This helper will check whether time slots would be released by the new state and
4396 * respond accordingly, along with ensuring the MST state is always added to the
4397 * atomic state whenever a new state would modify the state of payloads on the
4398 * topology.
4399 *
4400 * It is OK to call this even if @port has been removed from the system.
4401 * Additionally, it is OK to call this function multiple times on the same
4402 * @port as needed. It is not OK however, to call this function and
4403 * drm_dp_atomic_find_time_slots() on the same @port in a single atomic check
4404 * phase.
4405 *
4406 * See also:
4407 * drm_dp_atomic_find_time_slots()
4408 * drm_dp_mst_atomic_check()
4409 *
4410 * Returns:
4411 * 0 on success, negative error code otherwise
4412 */
drm_dp_atomic_release_time_slots(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4413 int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
4414 struct drm_dp_mst_topology_mgr *mgr,
4415 struct drm_dp_mst_port *port)
4416 {
4417 struct drm_dp_mst_topology_state *topology_state;
4418 struct drm_dp_mst_atomic_payload *payload;
4419 struct drm_connector_state *old_conn_state, *new_conn_state;
4420 bool update_payload = true;
4421
4422 old_conn_state = drm_atomic_get_old_connector_state(state, port->connector);
4423 if (!old_conn_state->crtc)
4424 return 0;
4425
4426 /* If the CRTC isn't disabled by this state, don't release it's payload */
4427 new_conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4428 if (new_conn_state->crtc) {
4429 struct drm_crtc_state *crtc_state =
4430 drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4431
4432 /* No modeset means no payload changes, so it's safe to not pull in the MST state */
4433 if (!crtc_state || !drm_atomic_crtc_needs_modeset(crtc_state))
4434 return 0;
4435
4436 if (!crtc_state->mode_changed && !crtc_state->connectors_changed)
4437 update_payload = false;
4438 }
4439
4440 topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4441 if (IS_ERR(topology_state))
4442 return PTR_ERR(topology_state);
4443
4444 topology_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4445 if (!update_payload)
4446 return 0;
4447
4448 payload = drm_atomic_get_mst_payload_state(topology_state, port);
4449 if (WARN_ON(!payload)) {
4450 drm_err(mgr->dev, "No payload for [MST PORT:%p] found in mst state %p\n",
4451 port, &topology_state->base);
4452 return -EINVAL;
4453 }
4454
4455 if (new_conn_state->crtc)
4456 return 0;
4457
4458 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] TU %d -> 0\n", port, payload->time_slots);
4459 if (!payload->delete) {
4460 payload->pbn = 0;
4461 payload->delete = true;
4462 topology_state->payload_mask &= ~BIT(payload->vcpi - 1);
4463 }
4464
4465 return 0;
4466 }
4467 EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
4468
4469 /**
4470 * drm_dp_mst_atomic_setup_commit() - setup_commit hook for MST helpers
4471 * @state: global atomic state
4472 *
4473 * This function saves all of the &drm_crtc_commit structs in an atomic state that touch any CRTCs
4474 * currently assigned to an MST topology. Drivers must call this hook from their
4475 * &drm_mode_config_helper_funcs.atomic_commit_setup hook.
4476 *
4477 * Returns:
4478 * 0 if all CRTC commits were retrieved successfully, negative error code otherwise
4479 */
drm_dp_mst_atomic_setup_commit(struct drm_atomic_state * state)4480 int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state)
4481 {
4482 struct drm_dp_mst_topology_mgr *mgr;
4483 struct drm_dp_mst_topology_state *mst_state;
4484 struct drm_crtc *crtc;
4485 struct drm_crtc_state *crtc_state;
4486 int i, j, commit_idx, num_commit_deps;
4487
4488 for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
4489 if (!mst_state->pending_crtc_mask)
4490 continue;
4491
4492 num_commit_deps = hweight32(mst_state->pending_crtc_mask);
4493 mst_state->commit_deps = kmalloc_array(num_commit_deps,
4494 sizeof(*mst_state->commit_deps), GFP_KERNEL);
4495 if (!mst_state->commit_deps)
4496 return -ENOMEM;
4497 mst_state->num_commit_deps = num_commit_deps;
4498
4499 commit_idx = 0;
4500 for_each_new_crtc_in_state(state, crtc, crtc_state, j) {
4501 if (mst_state->pending_crtc_mask & drm_crtc_mask(crtc)) {
4502 mst_state->commit_deps[commit_idx++] =
4503 drm_crtc_commit_get(crtc_state->commit);
4504 }
4505 }
4506 }
4507
4508 return 0;
4509 }
4510 EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
4511
4512 /**
4513 * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies,
4514 * prepare new MST state for commit
4515 * @state: global atomic state
4516 *
4517 * Goes through any MST topologies in this atomic state, and waits for any pending commits which
4518 * touched CRTCs that were/are on an MST topology to be programmed to hardware and flipped to before
4519 * returning. This is to prevent multiple non-blocking commits affecting an MST topology from racing
4520 * with eachother by forcing them to be executed sequentially in situations where the only resources
4521 * the modeset objects in these commits share are an MST topology.
4522 *
4523 * This function also prepares the new MST state for commit by performing some state preparation
4524 * which can't be done until this point, such as reading back the final VC start slots (which are
4525 * determined at commit-time) from the previous state.
4526 *
4527 * All MST drivers must call this function after calling drm_atomic_helper_wait_for_dependencies(),
4528 * or whatever their equivalent of that is.
4529 */
drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state * state)4530 void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
4531 {
4532 struct drm_dp_mst_topology_state *old_mst_state, *new_mst_state;
4533 struct drm_dp_mst_topology_mgr *mgr;
4534 struct drm_dp_mst_atomic_payload *old_payload, *new_payload;
4535 int i, j, ret;
4536
4537 for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state, new_mst_state, i) {
4538 for (j = 0; j < old_mst_state->num_commit_deps; j++) {
4539 ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]);
4540 if (ret < 0)
4541 drm_err(state->dev, "Failed to wait for %s: %d\n",
4542 old_mst_state->commit_deps[j]->crtc->name, ret);
4543 }
4544
4545 /* Now that previous state is committed, it's safe to copy over the start slot
4546 * and allocation status assignments
4547 */
4548 list_for_each_entry(old_payload, &old_mst_state->payloads, next) {
4549 if (old_payload->delete)
4550 continue;
4551
4552 new_payload = drm_atomic_get_mst_payload_state(new_mst_state,
4553 old_payload->port);
4554 new_payload->vc_start_slot = old_payload->vc_start_slot;
4555 new_payload->payload_allocation_status =
4556 old_payload->payload_allocation_status;
4557 }
4558 }
4559 }
4560 EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
4561
4562 /**
4563 * drm_dp_mst_root_conn_atomic_check() - Serialize CRTC commits on MST-capable connectors operating
4564 * in SST mode
4565 * @new_conn_state: The new connector state of the &drm_connector
4566 * @mgr: The MST topology manager for the &drm_connector
4567 *
4568 * Since MST uses fake &drm_encoder structs, the generic atomic modesetting code isn't able to
4569 * serialize non-blocking commits happening on the real DP connector of an MST topology switching
4570 * into/away from MST mode - as the CRTC on the real DP connector and the CRTCs on the connector's
4571 * MST topology will never share the same &drm_encoder.
4572 *
4573 * This function takes care of this serialization issue, by checking a root MST connector's atomic
4574 * state to determine if it is about to have a modeset - and then pulling in the MST topology state
4575 * if so, along with adding any relevant CRTCs to &drm_dp_mst_topology_state.pending_crtc_mask.
4576 *
4577 * Drivers implementing MST must call this function from the
4578 * &drm_connector_helper_funcs.atomic_check hook of any physical DP &drm_connector capable of
4579 * driving MST sinks.
4580 *
4581 * Returns:
4582 * 0 on success, negative error code otherwise
4583 */
drm_dp_mst_root_conn_atomic_check(struct drm_connector_state * new_conn_state,struct drm_dp_mst_topology_mgr * mgr)4584 int drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
4585 struct drm_dp_mst_topology_mgr *mgr)
4586 {
4587 struct drm_atomic_state *state = new_conn_state->state;
4588 struct drm_connector_state *old_conn_state =
4589 drm_atomic_get_old_connector_state(state, new_conn_state->connector);
4590 struct drm_crtc_state *crtc_state;
4591 struct drm_dp_mst_topology_state *mst_state = NULL;
4592
4593 if (new_conn_state->crtc) {
4594 crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4595 if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4596 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4597 if (IS_ERR(mst_state))
4598 return PTR_ERR(mst_state);
4599
4600 mst_state->pending_crtc_mask |= drm_crtc_mask(new_conn_state->crtc);
4601 }
4602 }
4603
4604 if (old_conn_state->crtc) {
4605 crtc_state = drm_atomic_get_new_crtc_state(state, old_conn_state->crtc);
4606 if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4607 if (!mst_state) {
4608 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4609 if (IS_ERR(mst_state))
4610 return PTR_ERR(mst_state);
4611 }
4612
4613 mst_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4614 }
4615 }
4616
4617 return 0;
4618 }
4619 EXPORT_SYMBOL(drm_dp_mst_root_conn_atomic_check);
4620
4621 /**
4622 * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
4623 * @mst_state: mst_state to update
4624 * @link_encoding_cap: the ecoding format on the link
4625 */
drm_dp_mst_update_slots(struct drm_dp_mst_topology_state * mst_state,uint8_t link_encoding_cap)4626 void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap)
4627 {
4628 if (link_encoding_cap == DP_CAP_ANSI_128B132B) {
4629 mst_state->total_avail_slots = 64;
4630 mst_state->start_slot = 0;
4631 } else {
4632 mst_state->total_avail_slots = 63;
4633 mst_state->start_slot = 1;
4634 }
4635
4636 DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n",
4637 (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b",
4638 mst_state);
4639 }
4640 EXPORT_SYMBOL(drm_dp_mst_update_slots);
4641
drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr * mgr,int id,u8 start_slot,u8 num_slots)4642 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4643 int id, u8 start_slot, u8 num_slots)
4644 {
4645 u8 payload_alloc[3], status;
4646 int ret;
4647 int retries = 0;
4648
4649 drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4650 DP_PAYLOAD_TABLE_UPDATED);
4651
4652 payload_alloc[0] = id;
4653 payload_alloc[1] = start_slot;
4654 payload_alloc[2] = num_slots;
4655
4656 ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4657 if (ret != 3) {
4658 drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4659 goto fail;
4660 }
4661
4662 retry:
4663 ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4664 if (ret < 0) {
4665 drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4666 goto fail;
4667 }
4668
4669 if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4670 retries++;
4671 if (retries < 20) {
4672 usleep_range(10000, 20000);
4673 goto retry;
4674 }
4675 drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4676 status);
4677 ret = -EINVAL;
4678 goto fail;
4679 }
4680 ret = 0;
4681 fail:
4682 return ret;
4683 }
4684
do_get_act_status(struct drm_dp_aux * aux)4685 static int do_get_act_status(struct drm_dp_aux *aux)
4686 {
4687 int ret;
4688 u8 status;
4689
4690 ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4691 if (ret < 0)
4692 return ret;
4693
4694 return status;
4695 }
4696
4697 /**
4698 * drm_dp_check_act_status() - Polls for ACT handled status.
4699 * @mgr: manager to use
4700 *
4701 * Tries waiting for the MST hub to finish updating it's payload table by
4702 * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4703 * take that long).
4704 *
4705 * Returns:
4706 * 0 if the ACT was handled in time, negative error code on failure.
4707 */
drm_dp_check_act_status(struct drm_dp_mst_topology_mgr * mgr)4708 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4709 {
4710 /*
4711 * There doesn't seem to be any recommended retry count or timeout in
4712 * the MST specification. Since some hubs have been observed to take
4713 * over 1 second to update their payload allocations under certain
4714 * conditions, we use a rather large timeout value.
4715 */
4716 const int timeout_ms = 3000;
4717 int ret, status;
4718
4719 ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4720 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4721 200, timeout_ms * USEC_PER_MSEC);
4722 if (ret < 0 && status >= 0) {
4723 drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4724 timeout_ms, status);
4725 return -EINVAL;
4726 } else if (status < 0) {
4727 /*
4728 * Failure here isn't unexpected - the hub may have
4729 * just been unplugged
4730 */
4731 drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4732 return status;
4733 }
4734
4735 return 0;
4736 }
4737 EXPORT_SYMBOL(drm_dp_check_act_status);
4738
4739 /**
4740 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4741 * @clock: dot clock
4742 * @bpp: bpp as .4 binary fixed point
4743 *
4744 * This uses the formula in the spec to calculate the PBN value for a mode.
4745 */
drm_dp_calc_pbn_mode(int clock,int bpp)4746 int drm_dp_calc_pbn_mode(int clock, int bpp)
4747 {
4748 /*
4749 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4750 * common multiplier to render an integer PBN for all link rate/lane
4751 * counts combinations
4752 * calculate
4753 * peak_kbps = clock * bpp / 16
4754 * peak_kbps *= SSC overhead / 1000000
4755 * peak_kbps /= 8 convert to Kbytes
4756 * peak_kBps *= (64/54) / 1000 convert to PBN
4757 */
4758 /*
4759 * TODO: Use the actual link and mode parameters to calculate
4760 * the overhead. For now it's assumed that these are
4761 * 4 link lanes, 4096 hactive pixels, which don't add any
4762 * significant data padding overhead and that there is no DSC
4763 * or FEC overhead.
4764 */
4765 int overhead = drm_dp_bw_overhead(4, 4096, 0, bpp,
4766 DRM_DP_BW_OVERHEAD_MST |
4767 DRM_DP_BW_OVERHEAD_SSC_REF_CLK);
4768
4769 return DIV64_U64_ROUND_UP(mul_u32_u32(clock * bpp, 64 * overhead >> 4),
4770 1000000ULL * 8 * 54 * 1000);
4771 }
4772 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4773
4774 /* we want to kick the TX after we've ack the up/down IRQs. */
drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr * mgr)4775 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4776 {
4777 queue_work(system_long_wq, &mgr->tx_work);
4778 }
4779
4780 /*
4781 * Helper function for parsing DP device types into convenient strings
4782 * for use with dp_mst_topology
4783 */
pdt_to_string(u8 pdt)4784 static const char *pdt_to_string(u8 pdt)
4785 {
4786 switch (pdt) {
4787 case DP_PEER_DEVICE_NONE:
4788 return "NONE";
4789 case DP_PEER_DEVICE_SOURCE_OR_SST:
4790 return "SOURCE OR SST";
4791 case DP_PEER_DEVICE_MST_BRANCHING:
4792 return "MST BRANCHING";
4793 case DP_PEER_DEVICE_SST_SINK:
4794 return "SST SINK";
4795 case DP_PEER_DEVICE_DP_LEGACY_CONV:
4796 return "DP LEGACY CONV";
4797 default:
4798 return "ERR";
4799 }
4800 }
4801
drm_dp_mst_dump_mstb(struct seq_file * m,struct drm_dp_mst_branch * mstb)4802 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4803 struct drm_dp_mst_branch *mstb)
4804 {
4805 struct drm_dp_mst_port *port;
4806 int tabs = mstb->lct;
4807 char prefix[10];
4808 int i;
4809
4810 for (i = 0; i < tabs; i++)
4811 prefix[i] = '\t';
4812 prefix[i] = '\0';
4813
4814 seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4815 list_for_each_entry(port, &mstb->ports, next) {
4816 seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4817 prefix,
4818 port->port_num,
4819 port,
4820 port->input ? "input" : "output",
4821 pdt_to_string(port->pdt),
4822 port->ddps,
4823 port->ldps,
4824 port->num_sdp_streams,
4825 port->num_sdp_stream_sinks,
4826 port->fec_capable ? "true" : "false",
4827 port->connector);
4828 if (port->mstb)
4829 drm_dp_mst_dump_mstb(m, port->mstb);
4830 }
4831 }
4832
4833 #define DP_PAYLOAD_TABLE_SIZE 64
4834
dump_dp_payload_table(struct drm_dp_mst_topology_mgr * mgr,char * buf)4835 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4836 char *buf)
4837 {
4838 int i;
4839
4840 for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4841 if (drm_dp_dpcd_read(mgr->aux,
4842 DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4843 &buf[i], 16) != 16)
4844 return false;
4845 }
4846 return true;
4847 }
4848
fetch_monitor_name(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,char * name,int namelen)4849 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4850 struct drm_dp_mst_port *port, char *name,
4851 int namelen)
4852 {
4853 struct edid *mst_edid;
4854
4855 mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4856 drm_edid_get_monitor_name(mst_edid, name, namelen);
4857 kfree(mst_edid);
4858 }
4859
4860 /**
4861 * drm_dp_mst_dump_topology(): dump topology to seq file.
4862 * @m: seq_file to dump output to
4863 * @mgr: manager to dump current topology for.
4864 *
4865 * helper to dump MST topology to a seq file for debugfs.
4866 */
drm_dp_mst_dump_topology(struct seq_file * m,struct drm_dp_mst_topology_mgr * mgr)4867 void drm_dp_mst_dump_topology(struct seq_file *m,
4868 struct drm_dp_mst_topology_mgr *mgr)
4869 {
4870 struct drm_dp_mst_topology_state *state;
4871 struct drm_dp_mst_atomic_payload *payload;
4872 int i, ret;
4873
4874 static const char *const status[] = {
4875 "None",
4876 "Local",
4877 "DFP",
4878 "Remote",
4879 };
4880
4881 mutex_lock(&mgr->lock);
4882 if (mgr->mst_primary)
4883 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4884
4885 /* dump VCPIs */
4886 mutex_unlock(&mgr->lock);
4887
4888 ret = drm_modeset_lock_single_interruptible(&mgr->base.lock);
4889 if (ret < 0)
4890 return;
4891
4892 state = to_drm_dp_mst_topology_state(mgr->base.state);
4893 seq_printf(m, "\n*** Atomic state info ***\n");
4894 seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n",
4895 state->payload_mask, mgr->max_payloads, state->start_slot,
4896 dfixed_trunc(state->pbn_div));
4897
4898 seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc | status | sink name |\n");
4899 for (i = 0; i < mgr->max_payloads; i++) {
4900 list_for_each_entry(payload, &state->payloads, next) {
4901 char name[14];
4902
4903 if (payload->vcpi != i || payload->delete)
4904 continue;
4905
4906 fetch_monitor_name(mgr, payload->port, name, sizeof(name));
4907 seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s %8s %19s\n",
4908 i,
4909 payload->port->port_num,
4910 payload->vcpi,
4911 payload->vc_start_slot,
4912 payload->vc_start_slot + payload->time_slots - 1,
4913 payload->pbn,
4914 payload->dsc_enabled ? "Y" : "N",
4915 status[payload->payload_allocation_status],
4916 (*name != 0) ? name : "Unknown");
4917 }
4918 }
4919
4920 seq_printf(m, "\n*** DPCD Info ***\n");
4921 mutex_lock(&mgr->lock);
4922 if (mgr->mst_primary) {
4923 u8 buf[DP_PAYLOAD_TABLE_SIZE];
4924 int ret;
4925
4926 if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
4927 seq_printf(m, "dpcd read failed\n");
4928 goto out;
4929 }
4930 seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4931
4932 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4933 if (ret != 2) {
4934 seq_printf(m, "faux/mst read failed\n");
4935 goto out;
4936 }
4937 seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4938
4939 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4940 if (ret != 1) {
4941 seq_printf(m, "mst ctrl read failed\n");
4942 goto out;
4943 }
4944 seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4945
4946 /* dump the standard OUI branch header */
4947 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4948 if (ret != DP_BRANCH_OUI_HEADER_SIZE) {
4949 seq_printf(m, "branch oui read failed\n");
4950 goto out;
4951 }
4952 seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4953
4954 for (i = 0x3; i < 0x8 && buf[i]; i++)
4955 seq_printf(m, "%c", buf[i]);
4956 seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4957 buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4958 if (dump_dp_payload_table(mgr, buf))
4959 seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4960 }
4961
4962 out:
4963 mutex_unlock(&mgr->lock);
4964 drm_modeset_unlock(&mgr->base.lock);
4965 }
4966 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4967
drm_dp_tx_work(struct work_struct * work)4968 static void drm_dp_tx_work(struct work_struct *work)
4969 {
4970 struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4971
4972 mutex_lock(&mgr->qlock);
4973 if (!list_empty(&mgr->tx_msg_downq))
4974 process_single_down_tx_qlock(mgr);
4975 mutex_unlock(&mgr->qlock);
4976 }
4977
4978 static inline void
drm_dp_delayed_destroy_port(struct drm_dp_mst_port * port)4979 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4980 {
4981 drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4982
4983 if (port->connector) {
4984 drm_connector_unregister(port->connector);
4985 drm_connector_put(port->connector);
4986 }
4987
4988 drm_dp_mst_put_port_malloc(port);
4989 }
4990
4991 static inline void
drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch * mstb)4992 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4993 {
4994 struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4995 struct drm_dp_mst_port *port, *port_tmp;
4996 struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4997 bool wake_tx = false;
4998
4999 mutex_lock(&mgr->lock);
5000 list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
5001 list_del(&port->next);
5002 drm_dp_mst_topology_put_port(port);
5003 }
5004 mutex_unlock(&mgr->lock);
5005
5006 /* drop any tx slot msg */
5007 mutex_lock(&mstb->mgr->qlock);
5008 list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
5009 if (txmsg->dst != mstb)
5010 continue;
5011
5012 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
5013 list_del(&txmsg->next);
5014 wake_tx = true;
5015 }
5016 mutex_unlock(&mstb->mgr->qlock);
5017
5018 if (wake_tx)
5019 wake_up_all(&mstb->mgr->tx_waitq);
5020
5021 drm_dp_mst_put_mstb_malloc(mstb);
5022 }
5023
drm_dp_delayed_destroy_work(struct work_struct * work)5024 static void drm_dp_delayed_destroy_work(struct work_struct *work)
5025 {
5026 struct drm_dp_mst_topology_mgr *mgr =
5027 container_of(work, struct drm_dp_mst_topology_mgr,
5028 delayed_destroy_work);
5029 bool send_hotplug = false, go_again;
5030
5031 /*
5032 * Not a regular list traverse as we have to drop the destroy
5033 * connector lock before destroying the mstb/port, to avoid AB->BA
5034 * ordering between this lock and the config mutex.
5035 */
5036 do {
5037 go_again = false;
5038
5039 for (;;) {
5040 struct drm_dp_mst_branch *mstb;
5041
5042 mutex_lock(&mgr->delayed_destroy_lock);
5043 mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
5044 struct drm_dp_mst_branch,
5045 destroy_next);
5046 if (mstb)
5047 list_del(&mstb->destroy_next);
5048 mutex_unlock(&mgr->delayed_destroy_lock);
5049
5050 if (!mstb)
5051 break;
5052
5053 drm_dp_delayed_destroy_mstb(mstb);
5054 go_again = true;
5055 }
5056
5057 for (;;) {
5058 struct drm_dp_mst_port *port;
5059
5060 mutex_lock(&mgr->delayed_destroy_lock);
5061 port = list_first_entry_or_null(&mgr->destroy_port_list,
5062 struct drm_dp_mst_port,
5063 next);
5064 if (port)
5065 list_del(&port->next);
5066 mutex_unlock(&mgr->delayed_destroy_lock);
5067
5068 if (!port)
5069 break;
5070
5071 drm_dp_delayed_destroy_port(port);
5072 send_hotplug = true;
5073 go_again = true;
5074 }
5075 } while (go_again);
5076
5077 if (send_hotplug)
5078 drm_kms_helper_hotplug_event(mgr->dev);
5079 }
5080
5081 static struct drm_private_state *
drm_dp_mst_duplicate_state(struct drm_private_obj * obj)5082 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5083 {
5084 struct drm_dp_mst_topology_state *state, *old_state =
5085 to_dp_mst_topology_state(obj->state);
5086 struct drm_dp_mst_atomic_payload *pos, *payload;
5087
5088 state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5089 if (!state)
5090 return NULL;
5091
5092 __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5093
5094 INIT_LIST_HEAD(&state->payloads);
5095 state->commit_deps = NULL;
5096 state->num_commit_deps = 0;
5097 state->pending_crtc_mask = 0;
5098
5099 list_for_each_entry(pos, &old_state->payloads, next) {
5100 /* Prune leftover freed timeslot allocations */
5101 if (pos->delete)
5102 continue;
5103
5104 payload = kmemdup(pos, sizeof(*payload), GFP_KERNEL);
5105 if (!payload)
5106 goto fail;
5107
5108 drm_dp_mst_get_port_malloc(payload->port);
5109 list_add(&payload->next, &state->payloads);
5110 }
5111
5112 return &state->base;
5113
5114 fail:
5115 list_for_each_entry_safe(pos, payload, &state->payloads, next) {
5116 drm_dp_mst_put_port_malloc(pos->port);
5117 kfree(pos);
5118 }
5119 kfree(state);
5120
5121 return NULL;
5122 }
5123
drm_dp_mst_destroy_state(struct drm_private_obj * obj,struct drm_private_state * state)5124 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5125 struct drm_private_state *state)
5126 {
5127 struct drm_dp_mst_topology_state *mst_state =
5128 to_dp_mst_topology_state(state);
5129 struct drm_dp_mst_atomic_payload *pos, *tmp;
5130 int i;
5131
5132 list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
5133 /* We only keep references to ports with active payloads */
5134 if (!pos->delete)
5135 drm_dp_mst_put_port_malloc(pos->port);
5136 kfree(pos);
5137 }
5138
5139 for (i = 0; i < mst_state->num_commit_deps; i++)
5140 drm_crtc_commit_put(mst_state->commit_deps[i]);
5141
5142 kfree(mst_state->commit_deps);
5143 kfree(mst_state);
5144 }
5145
drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port * port,struct drm_dp_mst_branch * branch)5146 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5147 struct drm_dp_mst_branch *branch)
5148 {
5149 while (port->parent) {
5150 if (port->parent == branch)
5151 return true;
5152
5153 if (port->parent->port_parent)
5154 port = port->parent->port_parent;
5155 else
5156 break;
5157 }
5158 return false;
5159 }
5160
5161 static bool
drm_dp_mst_port_downstream_of_parent_locked(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,struct drm_dp_mst_port * parent)5162 drm_dp_mst_port_downstream_of_parent_locked(struct drm_dp_mst_topology_mgr *mgr,
5163 struct drm_dp_mst_port *port,
5164 struct drm_dp_mst_port *parent)
5165 {
5166 if (!mgr->mst_primary)
5167 return false;
5168
5169 port = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary,
5170 port);
5171 if (!port)
5172 return false;
5173
5174 if (!parent)
5175 return true;
5176
5177 parent = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary,
5178 parent);
5179 if (!parent)
5180 return false;
5181
5182 if (!parent->mstb)
5183 return false;
5184
5185 return drm_dp_mst_port_downstream_of_branch(port, parent->mstb);
5186 }
5187
5188 /**
5189 * drm_dp_mst_port_downstream_of_parent - check if a port is downstream of a parent port
5190 * @mgr: MST topology manager
5191 * @port: the port being looked up
5192 * @parent: the parent port
5193 *
5194 * The function returns %true if @port is downstream of @parent. If @parent is
5195 * %NULL - denoting the root port - the function returns %true if @port is in
5196 * @mgr's topology.
5197 */
5198 bool
drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,struct drm_dp_mst_port * parent)5199 drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr *mgr,
5200 struct drm_dp_mst_port *port,
5201 struct drm_dp_mst_port *parent)
5202 {
5203 bool ret;
5204
5205 mutex_lock(&mgr->lock);
5206 ret = drm_dp_mst_port_downstream_of_parent_locked(mgr, port, parent);
5207 mutex_unlock(&mgr->lock);
5208
5209 return ret;
5210 }
5211 EXPORT_SYMBOL(drm_dp_mst_port_downstream_of_parent);
5212
5213 static int
5214 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5215 struct drm_dp_mst_topology_state *state,
5216 struct drm_dp_mst_port **failing_port);
5217
5218 static int
drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_topology_state * state,struct drm_dp_mst_port ** failing_port)5219 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5220 struct drm_dp_mst_topology_state *state,
5221 struct drm_dp_mst_port **failing_port)
5222 {
5223 struct drm_dp_mst_atomic_payload *payload;
5224 struct drm_dp_mst_port *port;
5225 int pbn_used = 0, ret;
5226 bool found = false;
5227
5228 /* Check that we have at least one port in our state that's downstream
5229 * of this branch, otherwise we can skip this branch
5230 */
5231 list_for_each_entry(payload, &state->payloads, next) {
5232 if (!payload->pbn ||
5233 !drm_dp_mst_port_downstream_of_branch(payload->port, mstb))
5234 continue;
5235
5236 found = true;
5237 break;
5238 }
5239 if (!found)
5240 return 0;
5241
5242 if (mstb->port_parent)
5243 drm_dbg_atomic(mstb->mgr->dev,
5244 "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5245 mstb->port_parent->parent, mstb->port_parent, mstb);
5246 else
5247 drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5248
5249 list_for_each_entry(port, &mstb->ports, next) {
5250 ret = drm_dp_mst_atomic_check_port_bw_limit(port, state, failing_port);
5251 if (ret < 0)
5252 return ret;
5253
5254 pbn_used += ret;
5255 }
5256
5257 return pbn_used;
5258 }
5259
5260 static int
drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port * port,struct drm_dp_mst_topology_state * state,struct drm_dp_mst_port ** failing_port)5261 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5262 struct drm_dp_mst_topology_state *state,
5263 struct drm_dp_mst_port **failing_port)
5264 {
5265 struct drm_dp_mst_atomic_payload *payload;
5266 int pbn_used = 0;
5267
5268 if (port->pdt == DP_PEER_DEVICE_NONE)
5269 return 0;
5270
5271 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5272 payload = drm_atomic_get_mst_payload_state(state, port);
5273 if (!payload)
5274 return 0;
5275
5276 /*
5277 * This could happen if the sink deasserted its HPD line, but
5278 * the branch device still reports it as attached (PDT != NONE).
5279 */
5280 if (!port->full_pbn) {
5281 drm_dbg_atomic(port->mgr->dev,
5282 "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5283 port->parent, port);
5284 *failing_port = port;
5285 return -EINVAL;
5286 }
5287
5288 pbn_used = payload->pbn;
5289 } else {
5290 pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5291 state,
5292 failing_port);
5293 if (pbn_used <= 0)
5294 return pbn_used;
5295 }
5296
5297 if (pbn_used > port->full_pbn) {
5298 drm_dbg_atomic(port->mgr->dev,
5299 "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5300 port->parent, port, pbn_used, port->full_pbn);
5301 *failing_port = port;
5302 return -ENOSPC;
5303 }
5304
5305 drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5306 port->parent, port, pbn_used, port->full_pbn);
5307
5308 return pbn_used;
5309 }
5310
5311 static inline int
drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_state * mst_state)5312 drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr,
5313 struct drm_dp_mst_topology_state *mst_state)
5314 {
5315 struct drm_dp_mst_atomic_payload *payload;
5316 int avail_slots = mst_state->total_avail_slots, payload_count = 0;
5317
5318 list_for_each_entry(payload, &mst_state->payloads, next) {
5319 /* Releasing payloads is always OK-even if the port is gone */
5320 if (payload->delete) {
5321 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all time slots\n",
5322 payload->port);
5323 continue;
5324 }
5325
5326 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d time slots\n",
5327 payload->port, payload->time_slots);
5328
5329 avail_slots -= payload->time_slots;
5330 if (avail_slots < 0) {
5331 drm_dbg_atomic(mgr->dev,
5332 "[MST PORT:%p] not enough time slots in mst state %p (avail=%d)\n",
5333 payload->port, mst_state, avail_slots + payload->time_slots);
5334 return -ENOSPC;
5335 }
5336
5337 if (++payload_count > mgr->max_payloads) {
5338 drm_dbg_atomic(mgr->dev,
5339 "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5340 mgr, mst_state, mgr->max_payloads);
5341 return -EINVAL;
5342 }
5343
5344 /* Assign a VCPI */
5345 if (!payload->vcpi) {
5346 payload->vcpi = ffz(mst_state->payload_mask) + 1;
5347 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] assigned VCPI #%d\n",
5348 payload->port, payload->vcpi);
5349 mst_state->payload_mask |= BIT(payload->vcpi - 1);
5350 }
5351 }
5352
5353 if (!payload_count)
5354 mst_state->pbn_div.full = dfixed_const(0);
5355
5356 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n",
5357 mgr, mst_state, dfixed_trunc(mst_state->pbn_div), avail_slots,
5358 mst_state->total_avail_slots - avail_slots);
5359
5360 return 0;
5361 }
5362
5363 /**
5364 * drm_dp_mst_add_affected_dsc_crtcs
5365 * @state: Pointer to the new struct drm_dp_mst_topology_state
5366 * @mgr: MST topology manager
5367 *
5368 * Whenever there is a change in mst topology
5369 * DSC configuration would have to be recalculated
5370 * therefore we need to trigger modeset on all affected
5371 * CRTCs in that topology
5372 *
5373 * See also:
5374 * drm_dp_mst_atomic_enable_dsc()
5375 */
drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr)5376 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5377 {
5378 struct drm_dp_mst_topology_state *mst_state;
5379 struct drm_dp_mst_atomic_payload *pos;
5380 struct drm_connector *connector;
5381 struct drm_connector_state *conn_state;
5382 struct drm_crtc *crtc;
5383 struct drm_crtc_state *crtc_state;
5384
5385 mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5386
5387 if (IS_ERR(mst_state))
5388 return PTR_ERR(mst_state);
5389
5390 list_for_each_entry(pos, &mst_state->payloads, next) {
5391
5392 connector = pos->port->connector;
5393
5394 if (!connector)
5395 return -EINVAL;
5396
5397 conn_state = drm_atomic_get_connector_state(state, connector);
5398
5399 if (IS_ERR(conn_state))
5400 return PTR_ERR(conn_state);
5401
5402 crtc = conn_state->crtc;
5403
5404 if (!crtc)
5405 continue;
5406
5407 if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5408 continue;
5409
5410 crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5411
5412 if (IS_ERR(crtc_state))
5413 return PTR_ERR(crtc_state);
5414
5415 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5416 mgr, crtc);
5417
5418 crtc_state->mode_changed = true;
5419 }
5420 return 0;
5421 }
5422 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5423
5424 /**
5425 * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5426 * @state: Pointer to the new drm_atomic_state
5427 * @port: Pointer to the affected MST Port
5428 * @pbn: Newly recalculated bw required for link with DSC enabled
5429 * @enable: Boolean flag to enable or disable DSC on the port
5430 *
5431 * This function enables DSC on the given Port
5432 * by recalculating its vcpi from pbn provided
5433 * and sets dsc_enable flag to keep track of which
5434 * ports have DSC enabled
5435 *
5436 */
drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state * state,struct drm_dp_mst_port * port,int pbn,bool enable)5437 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5438 struct drm_dp_mst_port *port,
5439 int pbn, bool enable)
5440 {
5441 struct drm_dp_mst_topology_state *mst_state;
5442 struct drm_dp_mst_atomic_payload *payload;
5443 int time_slots = 0;
5444
5445 mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5446 if (IS_ERR(mst_state))
5447 return PTR_ERR(mst_state);
5448
5449 payload = drm_atomic_get_mst_payload_state(mst_state, port);
5450 if (!payload) {
5451 drm_dbg_atomic(state->dev,
5452 "[MST PORT:%p] Couldn't find payload in mst state %p\n",
5453 port, mst_state);
5454 return -EINVAL;
5455 }
5456
5457 if (payload->dsc_enabled == enable) {
5458 drm_dbg_atomic(state->dev,
5459 "[MST PORT:%p] DSC flag is already set to %d, returning %d time slots\n",
5460 port, enable, payload->time_slots);
5461 time_slots = payload->time_slots;
5462 }
5463
5464 if (enable) {
5465 time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn);
5466 drm_dbg_atomic(state->dev,
5467 "[MST PORT:%p] Enabling DSC flag, reallocating %d time slots on the port\n",
5468 port, time_slots);
5469 if (time_slots < 0)
5470 return -EINVAL;
5471 }
5472
5473 payload->dsc_enabled = enable;
5474
5475 return time_slots;
5476 }
5477 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5478
5479 /**
5480 * drm_dp_mst_atomic_check_mgr - Check the atomic state of an MST topology manager
5481 * @state: The global atomic state
5482 * @mgr: Manager to check
5483 * @mst_state: The MST atomic state for @mgr
5484 * @failing_port: Returns the port with a BW limitation
5485 *
5486 * Checks the given MST manager's topology state for an atomic update to ensure
5487 * that it's valid. This includes checking whether there's enough bandwidth to
5488 * support the new timeslot allocations in the atomic update.
5489 *
5490 * Any atomic drivers supporting DP MST must make sure to call this or
5491 * the drm_dp_mst_atomic_check() function after checking the rest of their state
5492 * in their &drm_mode_config_funcs.atomic_check() callback.
5493 *
5494 * See also:
5495 * drm_dp_mst_atomic_check()
5496 * drm_dp_atomic_find_time_slots()
5497 * drm_dp_atomic_release_time_slots()
5498 *
5499 * Returns:
5500 * - 0 if the new state is valid
5501 * - %-ENOSPC, if the new state is invalid, because of BW limitation
5502 * @failing_port is set to:
5503 *
5504 * - The non-root port where a BW limit check failed
5505 * with all the ports downstream of @failing_port passing
5506 * the BW limit check.
5507 * The returned port pointer is valid until at least
5508 * one payload downstream of it exists.
5509 * - %NULL if the BW limit check failed at the root port
5510 * with all the ports downstream of the root port passing
5511 * the BW limit check.
5512 *
5513 * - %-EINVAL, if the new state is invalid, because the root port has
5514 * too many payloads.
5515 */
drm_dp_mst_atomic_check_mgr(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_state * mst_state,struct drm_dp_mst_port ** failing_port)5516 int drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state,
5517 struct drm_dp_mst_topology_mgr *mgr,
5518 struct drm_dp_mst_topology_state *mst_state,
5519 struct drm_dp_mst_port **failing_port)
5520 {
5521 int ret;
5522
5523 *failing_port = NULL;
5524
5525 if (!mgr->mst_state)
5526 return 0;
5527
5528 mutex_lock(&mgr->lock);
5529 ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5530 mst_state,
5531 failing_port);
5532 mutex_unlock(&mgr->lock);
5533
5534 if (ret < 0)
5535 return ret;
5536
5537 return drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state);
5538 }
5539 EXPORT_SYMBOL(drm_dp_mst_atomic_check_mgr);
5540
5541 /**
5542 * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5543 * atomic update is valid
5544 * @state: Pointer to the new &struct drm_dp_mst_topology_state
5545 *
5546 * Checks the given topology state for an atomic update to ensure that it's
5547 * valid, calling drm_dp_mst_atomic_check_mgr() for all MST manager in the
5548 * atomic state. This includes checking whether there's enough bandwidth to
5549 * support the new timeslot allocations in the atomic update.
5550 *
5551 * Any atomic drivers supporting DP MST must make sure to call this after
5552 * checking the rest of their state in their
5553 * &drm_mode_config_funcs.atomic_check() callback.
5554 *
5555 * See also:
5556 * drm_dp_mst_atomic_check_mgr()
5557 * drm_dp_atomic_find_time_slots()
5558 * drm_dp_atomic_release_time_slots()
5559 *
5560 * Returns:
5561 *
5562 * 0 if the new state is valid, negative error code otherwise.
5563 */
drm_dp_mst_atomic_check(struct drm_atomic_state * state)5564 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5565 {
5566 struct drm_dp_mst_topology_mgr *mgr;
5567 struct drm_dp_mst_topology_state *mst_state;
5568 int i, ret = 0;
5569
5570 for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5571 struct drm_dp_mst_port *tmp_port;
5572
5573 ret = drm_dp_mst_atomic_check_mgr(state, mgr, mst_state, &tmp_port);
5574 if (ret)
5575 break;
5576 }
5577
5578 return ret;
5579 }
5580 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5581
5582 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5583 .atomic_duplicate_state = drm_dp_mst_duplicate_state,
5584 .atomic_destroy_state = drm_dp_mst_destroy_state,
5585 };
5586 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5587
5588 /**
5589 * drm_atomic_get_mst_topology_state: get MST topology state
5590 * @state: global atomic state
5591 * @mgr: MST topology manager, also the private object in this case
5592 *
5593 * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5594 * state vtable so that the private object state returned is that of a MST
5595 * topology object.
5596 *
5597 * RETURNS:
5598 *
5599 * The MST topology state or error pointer.
5600 */
drm_atomic_get_mst_topology_state(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr)5601 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5602 struct drm_dp_mst_topology_mgr *mgr)
5603 {
5604 return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5605 }
5606 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5607
5608 /**
5609 * drm_atomic_get_old_mst_topology_state: get old MST topology state in atomic state, if any
5610 * @state: global atomic state
5611 * @mgr: MST topology manager, also the private object in this case
5612 *
5613 * This function wraps drm_atomic_get_old_private_obj_state() passing in the MST atomic
5614 * state vtable so that the private object state returned is that of a MST
5615 * topology object.
5616 *
5617 * Returns:
5618 *
5619 * The old MST topology state, or NULL if there's no topology state for this MST mgr
5620 * in the global atomic state
5621 */
5622 struct drm_dp_mst_topology_state *
drm_atomic_get_old_mst_topology_state(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr)5623 drm_atomic_get_old_mst_topology_state(struct drm_atomic_state *state,
5624 struct drm_dp_mst_topology_mgr *mgr)
5625 {
5626 struct drm_private_state *old_priv_state =
5627 drm_atomic_get_old_private_obj_state(state, &mgr->base);
5628
5629 return old_priv_state ? to_dp_mst_topology_state(old_priv_state) : NULL;
5630 }
5631 EXPORT_SYMBOL(drm_atomic_get_old_mst_topology_state);
5632
5633 /**
5634 * drm_atomic_get_new_mst_topology_state: get new MST topology state in atomic state, if any
5635 * @state: global atomic state
5636 * @mgr: MST topology manager, also the private object in this case
5637 *
5638 * This function wraps drm_atomic_get_new_private_obj_state() passing in the MST atomic
5639 * state vtable so that the private object state returned is that of a MST
5640 * topology object.
5641 *
5642 * Returns:
5643 *
5644 * The new MST topology state, or NULL if there's no topology state for this MST mgr
5645 * in the global atomic state
5646 */
5647 struct drm_dp_mst_topology_state *
drm_atomic_get_new_mst_topology_state(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr)5648 drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
5649 struct drm_dp_mst_topology_mgr *mgr)
5650 {
5651 struct drm_private_state *new_priv_state =
5652 drm_atomic_get_new_private_obj_state(state, &mgr->base);
5653
5654 return new_priv_state ? to_dp_mst_topology_state(new_priv_state) : NULL;
5655 }
5656 EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
5657
5658 /**
5659 * drm_dp_mst_topology_mgr_init - initialise a topology manager
5660 * @mgr: manager struct to initialise
5661 * @dev: device providing this structure - for i2c addition.
5662 * @aux: DP helper aux channel to talk to this device
5663 * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5664 * @max_payloads: maximum number of payloads this GPU can source
5665 * @conn_base_id: the connector object ID the MST device is connected to.
5666 *
5667 * Return 0 for success, or negative error code on failure
5668 */
drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr * mgr,struct drm_device * dev,struct drm_dp_aux * aux,int max_dpcd_transaction_bytes,int max_payloads,int conn_base_id)5669 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5670 struct drm_device *dev, struct drm_dp_aux *aux,
5671 int max_dpcd_transaction_bytes, int max_payloads,
5672 int conn_base_id)
5673 {
5674 struct drm_dp_mst_topology_state *mst_state;
5675
5676 mutex_init(&mgr->lock);
5677 mutex_init(&mgr->qlock);
5678 mutex_init(&mgr->delayed_destroy_lock);
5679 mutex_init(&mgr->up_req_lock);
5680 mutex_init(&mgr->probe_lock);
5681 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5682 mutex_init(&mgr->topology_ref_history_lock);
5683 stack_depot_init();
5684 #endif
5685 INIT_LIST_HEAD(&mgr->tx_msg_downq);
5686 INIT_LIST_HEAD(&mgr->destroy_port_list);
5687 INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5688 INIT_LIST_HEAD(&mgr->up_req_list);
5689
5690 /*
5691 * delayed_destroy_work will be queued on a dedicated WQ, so that any
5692 * requeuing will be also flushed when deiniting the topology manager.
5693 */
5694 mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5695 if (mgr->delayed_destroy_wq == NULL)
5696 return -ENOMEM;
5697
5698 INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5699 INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5700 INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5701 INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5702 init_waitqueue_head(&mgr->tx_waitq);
5703 mgr->dev = dev;
5704 mgr->aux = aux;
5705 mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5706 mgr->max_payloads = max_payloads;
5707 mgr->conn_base_id = conn_base_id;
5708
5709 mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5710 if (mst_state == NULL)
5711 return -ENOMEM;
5712
5713 mst_state->total_avail_slots = 63;
5714 mst_state->start_slot = 1;
5715
5716 mst_state->mgr = mgr;
5717 INIT_LIST_HEAD(&mst_state->payloads);
5718
5719 drm_atomic_private_obj_init(dev, &mgr->base,
5720 &mst_state->base,
5721 &drm_dp_mst_topology_state_funcs);
5722
5723 return 0;
5724 }
5725 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5726
5727 /**
5728 * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5729 * @mgr: manager to destroy
5730 */
drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr * mgr)5731 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5732 {
5733 drm_dp_mst_topology_mgr_set_mst(mgr, false);
5734 flush_work(&mgr->work);
5735 /* The following will also drain any requeued work on the WQ. */
5736 if (mgr->delayed_destroy_wq) {
5737 destroy_workqueue(mgr->delayed_destroy_wq);
5738 mgr->delayed_destroy_wq = NULL;
5739 }
5740 mgr->dev = NULL;
5741 mgr->aux = NULL;
5742 drm_atomic_private_obj_fini(&mgr->base);
5743 mgr->funcs = NULL;
5744
5745 mutex_destroy(&mgr->delayed_destroy_lock);
5746 mutex_destroy(&mgr->qlock);
5747 mutex_destroy(&mgr->lock);
5748 mutex_destroy(&mgr->up_req_lock);
5749 mutex_destroy(&mgr->probe_lock);
5750 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5751 mutex_destroy(&mgr->topology_ref_history_lock);
5752 #endif
5753 }
5754 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5755
remote_i2c_read_ok(const struct i2c_msg msgs[],int num)5756 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5757 {
5758 int i;
5759
5760 if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5761 return false;
5762
5763 for (i = 0; i < num - 1; i++) {
5764 if (msgs[i].flags & I2C_M_RD ||
5765 msgs[i].len > 0xff)
5766 return false;
5767 }
5768
5769 return msgs[num - 1].flags & I2C_M_RD &&
5770 msgs[num - 1].len <= 0xff;
5771 }
5772
remote_i2c_write_ok(const struct i2c_msg msgs[],int num)5773 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5774 {
5775 int i;
5776
5777 for (i = 0; i < num - 1; i++) {
5778 if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5779 msgs[i].len > 0xff)
5780 return false;
5781 }
5782
5783 return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5784 }
5785
drm_dp_mst_i2c_read(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port,struct i2c_msg * msgs,int num)5786 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5787 struct drm_dp_mst_port *port,
5788 struct i2c_msg *msgs, int num)
5789 {
5790 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5791 unsigned int i;
5792 struct drm_dp_sideband_msg_req_body msg;
5793 struct drm_dp_sideband_msg_tx *txmsg = NULL;
5794 int ret;
5795
5796 memset(&msg, 0, sizeof(msg));
5797 msg.req_type = DP_REMOTE_I2C_READ;
5798 msg.u.i2c_read.num_transactions = num - 1;
5799 msg.u.i2c_read.port_number = port->port_num;
5800 for (i = 0; i < num - 1; i++) {
5801 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5802 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5803 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5804 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5805 }
5806 msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5807 msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5808
5809 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5810 if (!txmsg) {
5811 ret = -ENOMEM;
5812 goto out;
5813 }
5814
5815 txmsg->dst = mstb;
5816 drm_dp_encode_sideband_req(&msg, txmsg);
5817
5818 drm_dp_queue_down_tx(mgr, txmsg);
5819
5820 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5821 if (ret > 0) {
5822
5823 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5824 ret = -EREMOTEIO;
5825 goto out;
5826 }
5827 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5828 ret = -EIO;
5829 goto out;
5830 }
5831 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5832 ret = num;
5833 }
5834 out:
5835 kfree(txmsg);
5836 return ret;
5837 }
5838
drm_dp_mst_i2c_write(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port,struct i2c_msg * msgs,int num)5839 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5840 struct drm_dp_mst_port *port,
5841 struct i2c_msg *msgs, int num)
5842 {
5843 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5844 unsigned int i;
5845 struct drm_dp_sideband_msg_req_body msg;
5846 struct drm_dp_sideband_msg_tx *txmsg = NULL;
5847 int ret;
5848
5849 txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5850 if (!txmsg) {
5851 ret = -ENOMEM;
5852 goto out;
5853 }
5854 for (i = 0; i < num; i++) {
5855 memset(&msg, 0, sizeof(msg));
5856 msg.req_type = DP_REMOTE_I2C_WRITE;
5857 msg.u.i2c_write.port_number = port->port_num;
5858 msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5859 msg.u.i2c_write.num_bytes = msgs[i].len;
5860 msg.u.i2c_write.bytes = msgs[i].buf;
5861
5862 memset(txmsg, 0, sizeof(*txmsg));
5863 txmsg->dst = mstb;
5864
5865 drm_dp_encode_sideband_req(&msg, txmsg);
5866 drm_dp_queue_down_tx(mgr, txmsg);
5867
5868 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5869 if (ret > 0) {
5870 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5871 ret = -EREMOTEIO;
5872 goto out;
5873 }
5874 } else {
5875 goto out;
5876 }
5877 }
5878 ret = num;
5879 out:
5880 kfree(txmsg);
5881 return ret;
5882 }
5883
5884 /* I2C device */
drm_dp_mst_i2c_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int num)5885 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5886 struct i2c_msg *msgs, int num)
5887 {
5888 struct drm_dp_aux *aux = adapter->algo_data;
5889 struct drm_dp_mst_port *port =
5890 container_of(aux, struct drm_dp_mst_port, aux);
5891 struct drm_dp_mst_branch *mstb;
5892 struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5893 int ret;
5894
5895 mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5896 if (!mstb)
5897 return -EREMOTEIO;
5898
5899 if (remote_i2c_read_ok(msgs, num)) {
5900 ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5901 } else if (remote_i2c_write_ok(msgs, num)) {
5902 ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5903 } else {
5904 drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5905 ret = -EIO;
5906 }
5907
5908 drm_dp_mst_topology_put_mstb(mstb);
5909 return ret;
5910 }
5911
drm_dp_mst_i2c_functionality(struct i2c_adapter * adapter)5912 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5913 {
5914 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5915 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5916 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5917 I2C_FUNC_10BIT_ADDR;
5918 }
5919
5920 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5921 .functionality = drm_dp_mst_i2c_functionality,
5922 .master_xfer = drm_dp_mst_i2c_xfer,
5923 };
5924
5925 /**
5926 * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5927 * @port: The port to add the I2C bus on
5928 *
5929 * Returns 0 on success or a negative error code on failure.
5930 */
drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port * port)5931 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5932 {
5933 struct drm_dp_aux *aux = &port->aux;
5934 struct device *parent_dev = port->mgr->dev->dev;
5935
5936 aux->ddc.algo = &drm_dp_mst_i2c_algo;
5937 aux->ddc.algo_data = aux;
5938 aux->ddc.retries = 3;
5939
5940 aux->ddc.owner = THIS_MODULE;
5941 /* FIXME: set the kdev of the port's connector as parent */
5942 aux->ddc.dev.parent = parent_dev;
5943 aux->ddc.dev.of_node = parent_dev->of_node;
5944
5945 strscpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5946 sizeof(aux->ddc.name));
5947
5948 return i2c_add_adapter(&aux->ddc);
5949 }
5950
5951 /**
5952 * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5953 * @port: The port to remove the I2C bus from
5954 */
drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port * port)5955 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5956 {
5957 i2c_del_adapter(&port->aux.ddc);
5958 }
5959
5960 /**
5961 * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5962 * @port: The port to check
5963 *
5964 * A single physical MST hub object can be represented in the topology
5965 * by multiple branches, with virtual ports between those branches.
5966 *
5967 * As of DP1.4, An MST hub with internal (virtual) ports must expose
5968 * certain DPCD registers over those ports. See sections 2.6.1.1.1
5969 * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5970 *
5971 * May acquire mgr->lock
5972 *
5973 * Returns:
5974 * true if the port is a virtual DP peer device, false otherwise
5975 */
drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port * port)5976 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5977 {
5978 struct drm_dp_mst_port *downstream_port;
5979
5980 if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5981 return false;
5982
5983 /* Virtual DP Sink (Internal Display Panel) */
5984 if (drm_dp_mst_port_is_logical(port))
5985 return true;
5986
5987 /* DP-to-HDMI Protocol Converter */
5988 if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5989 !port->mcs &&
5990 port->ldps)
5991 return true;
5992
5993 /* DP-to-DP */
5994 mutex_lock(&port->mgr->lock);
5995 if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5996 port->mstb &&
5997 port->mstb->num_ports == 2) {
5998 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5999 if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
6000 !downstream_port->input) {
6001 mutex_unlock(&port->mgr->lock);
6002 return true;
6003 }
6004 }
6005 }
6006 mutex_unlock(&port->mgr->lock);
6007
6008 return false;
6009 }
6010
6011 /**
6012 * drm_dp_mst_aux_for_parent() - Get the AUX device for an MST port's parent
6013 * @port: MST port whose parent's AUX device is returned
6014 *
6015 * Return the AUX device for @port's parent or NULL if port's parent is the
6016 * root port.
6017 */
drm_dp_mst_aux_for_parent(struct drm_dp_mst_port * port)6018 struct drm_dp_aux *drm_dp_mst_aux_for_parent(struct drm_dp_mst_port *port)
6019 {
6020 if (!port->parent || !port->parent->port_parent)
6021 return NULL;
6022
6023 return &port->parent->port_parent->aux;
6024 }
6025 EXPORT_SYMBOL(drm_dp_mst_aux_for_parent);
6026
6027 /**
6028 * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
6029 * @port: The port to check. A leaf of the MST tree with an attached display.
6030 *
6031 * Depending on the situation, DSC may be enabled via the endpoint aux,
6032 * the immediately upstream aux, or the connector's physical aux.
6033 *
6034 * This is both the correct aux to read DSC_CAPABILITY and the
6035 * correct aux to write DSC_ENABLED.
6036 *
6037 * This operation can be expensive (up to four aux reads), so
6038 * the caller should cache the return.
6039 *
6040 * Returns:
6041 * NULL if DSC cannot be enabled on this port, otherwise the aux device
6042 */
drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port * port)6043 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
6044 {
6045 struct drm_dp_mst_port *immediate_upstream_port;
6046 struct drm_dp_aux *immediate_upstream_aux;
6047 struct drm_dp_mst_port *fec_port;
6048 struct drm_dp_desc desc = {};
6049 u8 endpoint_fec;
6050 u8 endpoint_dsc;
6051
6052 if (!port)
6053 return NULL;
6054
6055 if (port->parent->port_parent)
6056 immediate_upstream_port = port->parent->port_parent;
6057 else
6058 immediate_upstream_port = NULL;
6059
6060 fec_port = immediate_upstream_port;
6061 while (fec_port) {
6062 /*
6063 * Each physical link (i.e. not a virtual port) between the
6064 * output and the primary device must support FEC
6065 */
6066 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
6067 !fec_port->fec_capable)
6068 return NULL;
6069
6070 fec_port = fec_port->parent->port_parent;
6071 }
6072
6073 /* DP-to-DP peer device */
6074 if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
6075 u8 upstream_dsc;
6076
6077 if (drm_dp_dpcd_read(&port->aux,
6078 DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
6079 return NULL;
6080 if (drm_dp_dpcd_read(&port->aux,
6081 DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
6082 return NULL;
6083 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
6084 DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
6085 return NULL;
6086
6087 /* Enpoint decompression with DP-to-DP peer device */
6088 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
6089 (endpoint_fec & DP_FEC_CAPABLE) &&
6090 (upstream_dsc & DP_DSC_PASSTHROUGH_IS_SUPPORTED)) {
6091 port->passthrough_aux = &immediate_upstream_port->aux;
6092 return &port->aux;
6093 }
6094
6095 /* Virtual DPCD decompression with DP-to-DP peer device */
6096 return &immediate_upstream_port->aux;
6097 }
6098
6099 /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
6100 if (drm_dp_mst_is_virtual_dpcd(port))
6101 return &port->aux;
6102
6103 /*
6104 * Synaptics quirk
6105 * Applies to ports for which:
6106 * - Physical aux has Synaptics OUI
6107 * - DPv1.4 or higher
6108 * - Port is on primary branch device
6109 * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
6110 */
6111 if (immediate_upstream_port)
6112 immediate_upstream_aux = &immediate_upstream_port->aux;
6113 else
6114 immediate_upstream_aux = port->mgr->aux;
6115
6116 if (drm_dp_read_desc(immediate_upstream_aux, &desc, true))
6117 return NULL;
6118
6119 if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD)) {
6120 u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
6121
6122 if (drm_dp_read_dpcd_caps(immediate_upstream_aux, dpcd_ext) < 0)
6123 return NULL;
6124
6125 if (dpcd_ext[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
6126 ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
6127 ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
6128 != DP_DWN_STRM_PORT_TYPE_ANALOG)))
6129 return immediate_upstream_aux;
6130 }
6131
6132 /*
6133 * The check below verifies if the MST sink
6134 * connected to the GPU is capable of DSC -
6135 * therefore the endpoint needs to be
6136 * both DSC and FEC capable.
6137 */
6138 if (drm_dp_dpcd_read(&port->aux,
6139 DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
6140 return NULL;
6141 if (drm_dp_dpcd_read(&port->aux,
6142 DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
6143 return NULL;
6144 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
6145 (endpoint_fec & DP_FEC_CAPABLE))
6146 return &port->aux;
6147
6148 return NULL;
6149 }
6150 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);
6151