1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) IBM Corporation 2017
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERGCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15 #include <linux/device.h>
16 #include <linux/errno.h>
17 #include <linux/fs.h>
18 #include <linux/fsi.h>
19 #include <linux/fsi-sbefifo.h>
20 #include <linux/kernel.h>
21 #include <linux/cdev.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 #include <linux/of.h>
25 #include <linux/of_platform.h>
26 #include <linux/platform_device.h>
27 #include <linux/sched.h>
28 #include <linux/slab.h>
29 #include <linux/uaccess.h>
30 #include <linux/delay.h>
31 #include <linux/uio.h>
32 #include <linux/vmalloc.h>
33 #include <linux/mm.h>
34
35 #include <uapi/linux/fsi.h>
36
37 /*
38 * The SBEFIFO is a pipe-like FSI device for communicating with
39 * the self boot engine on POWER processors.
40 */
41
42 #define DEVICE_NAME "sbefifo"
43 #define FSI_ENGID_SBE 0x22
44
45 /*
46 * Register layout
47 */
48
49 /* Register banks */
50 #define SBEFIFO_UP 0x00 /* FSI -> Host */
51 #define SBEFIFO_DOWN 0x40 /* Host -> FSI */
52
53 /* Per-bank registers */
54 #define SBEFIFO_FIFO 0x00 /* The FIFO itself */
55 #define SBEFIFO_STS 0x04 /* Status register */
56 #define SBEFIFO_STS_PARITY_ERR 0x20000000
57 #define SBEFIFO_STS_RESET_REQ 0x02000000
58 #define SBEFIFO_STS_GOT_EOT 0x00800000
59 #define SBEFIFO_STS_MAX_XFER_LIMIT 0x00400000
60 #define SBEFIFO_STS_FULL 0x00200000
61 #define SBEFIFO_STS_EMPTY 0x00100000
62 #define SBEFIFO_STS_ECNT_MASK 0x000f0000
63 #define SBEFIFO_STS_ECNT_SHIFT 16
64 #define SBEFIFO_STS_VALID_MASK 0x0000ff00
65 #define SBEFIFO_STS_VALID_SHIFT 8
66 #define SBEFIFO_STS_EOT_MASK 0x000000ff
67 #define SBEFIFO_STS_EOT_SHIFT 0
68 #define SBEFIFO_EOT_RAISE 0x08 /* (Up only) Set End Of Transfer */
69 #define SBEFIFO_REQ_RESET 0x0C /* (Up only) Reset Request */
70 #define SBEFIFO_PERFORM_RESET 0x10 /* (Down only) Perform Reset */
71 #define SBEFIFO_EOT_ACK 0x14 /* (Down only) Acknowledge EOT */
72 #define SBEFIFO_DOWN_MAX 0x18 /* (Down only) Max transfer */
73
74 /* CFAM GP Mailbox SelfBoot Message register */
75 #define CFAM_GP_MBOX_SBM_ADDR 0x2824 /* Converted 0x2809 */
76
77 #define CFAM_SBM_SBE_BOOTED 0x80000000
78 #define CFAM_SBM_SBE_ASYNC_FFDC 0x40000000
79 #define CFAM_SBM_SBE_STATE_MASK 0x00f00000
80 #define CFAM_SBM_SBE_STATE_SHIFT 20
81
82 enum sbe_state
83 {
84 SBE_STATE_UNKNOWN = 0x0, // Unknown, initial state
85 SBE_STATE_IPLING = 0x1, // IPL'ing - autonomous mode (transient)
86 SBE_STATE_ISTEP = 0x2, // ISTEP - Running IPL by steps (transient)
87 SBE_STATE_MPIPL = 0x3, // MPIPL
88 SBE_STATE_RUNTIME = 0x4, // SBE Runtime
89 SBE_STATE_DMT = 0x5, // Dead Man Timer State (transient)
90 SBE_STATE_DUMP = 0x6, // Dumping
91 SBE_STATE_FAILURE = 0x7, // Internal SBE failure
92 SBE_STATE_QUIESCE = 0x8, // Final state - needs SBE reset to get out
93 };
94
95 /* FIFO depth */
96 #define SBEFIFO_FIFO_DEPTH 8
97
98 /* Helpers */
99 #define sbefifo_empty(sts) ((sts) & SBEFIFO_STS_EMPTY)
100 #define sbefifo_full(sts) ((sts) & SBEFIFO_STS_FULL)
101 #define sbefifo_parity_err(sts) ((sts) & SBEFIFO_STS_PARITY_ERR)
102 #define sbefifo_populated(sts) (((sts) & SBEFIFO_STS_ECNT_MASK) >> SBEFIFO_STS_ECNT_SHIFT)
103 #define sbefifo_vacant(sts) (SBEFIFO_FIFO_DEPTH - sbefifo_populated(sts))
104 #define sbefifo_eot_set(sts) (((sts) & SBEFIFO_STS_EOT_MASK) >> SBEFIFO_STS_EOT_SHIFT)
105
106 /* Reset request timeout in ms */
107 #define SBEFIFO_RESET_TIMEOUT 10000
108
109 /* Timeouts for commands in ms */
110 #define SBEFIFO_TIMEOUT_START_CMD 10000
111 #define SBEFIFO_TIMEOUT_IN_CMD 1000
112 #define SBEFIFO_TIMEOUT_START_RSP 10000
113 #define SBEFIFO_TIMEOUT_IN_RSP 1000
114
115 /* Other constants */
116 #define SBEFIFO_MAX_USER_CMD_LEN (0x100000 + PAGE_SIZE)
117 #define SBEFIFO_RESET_MAGIC 0x52534554 /* "RSET" */
118
119 struct sbefifo {
120 uint32_t magic;
121 #define SBEFIFO_MAGIC 0x53424546 /* "SBEF" */
122 struct fsi_device *fsi_dev;
123 struct device dev;
124 struct cdev cdev;
125 struct mutex lock;
126 bool broken;
127 bool dead;
128 bool async_ffdc;
129 bool timed_out;
130 u32 timeout_in_cmd_ms;
131 u32 timeout_start_rsp_ms;
132 };
133
134 struct sbefifo_user {
135 struct sbefifo *sbefifo;
136 struct mutex file_lock;
137 void *cmd_page;
138 void *pending_cmd;
139 size_t pending_len;
140 u32 cmd_timeout_ms;
141 u32 read_timeout_ms;
142 };
143
144 static DEFINE_MUTEX(sbefifo_ffdc_mutex);
145
timeout_show(struct device * dev,struct device_attribute * attr,char * buf)146 static ssize_t timeout_show(struct device *dev, struct device_attribute *attr,
147 char *buf)
148 {
149 struct sbefifo *sbefifo = container_of(dev, struct sbefifo, dev);
150
151 return sysfs_emit(buf, "%d\n", sbefifo->timed_out ? 1 : 0);
152 }
153 static DEVICE_ATTR_RO(timeout);
154
__sbefifo_dump_ffdc(struct device * dev,const __be32 * ffdc,size_t ffdc_sz,bool internal)155 static void __sbefifo_dump_ffdc(struct device *dev, const __be32 *ffdc,
156 size_t ffdc_sz, bool internal)
157 {
158 int pack = 0;
159 #define FFDC_LSIZE 60
160 static char ffdc_line[FFDC_LSIZE];
161 char *p = ffdc_line;
162
163 while (ffdc_sz) {
164 u32 w0, w1, w2, i;
165 if (ffdc_sz < 3) {
166 dev_err(dev, "SBE invalid FFDC package size %zd\n", ffdc_sz);
167 return;
168 }
169 w0 = be32_to_cpu(*(ffdc++));
170 w1 = be32_to_cpu(*(ffdc++));
171 w2 = be32_to_cpu(*(ffdc++));
172 ffdc_sz -= 3;
173 if ((w0 >> 16) != 0xFFDC) {
174 dev_err(dev, "SBE invalid FFDC package signature %08x %08x %08x\n",
175 w0, w1, w2);
176 break;
177 }
178 w0 &= 0xffff;
179 if (w0 > ffdc_sz) {
180 dev_err(dev, "SBE FFDC package len %d words but only %zd remaining\n",
181 w0, ffdc_sz);
182 w0 = ffdc_sz;
183 break;
184 }
185 if (internal) {
186 dev_warn(dev, "+---- SBE FFDC package %d for async err -----+\n",
187 pack++);
188 } else {
189 dev_warn(dev, "+---- SBE FFDC package %d for cmd %02x:%02x -----+\n",
190 pack++, (w1 >> 8) & 0xff, w1 & 0xff);
191 }
192 dev_warn(dev, "| Response code: %08x |\n", w2);
193 dev_warn(dev, "|-------------------------------------------|\n");
194 for (i = 0; i < w0; i++) {
195 if ((i & 3) == 0) {
196 p = ffdc_line;
197 p += sprintf(p, "| %04x:", i << 4);
198 }
199 p += sprintf(p, " %08x", be32_to_cpu(*(ffdc++)));
200 ffdc_sz--;
201 if ((i & 3) == 3 || i == (w0 - 1)) {
202 while ((i & 3) < 3) {
203 p += sprintf(p, " ");
204 i++;
205 }
206 dev_warn(dev, "%s |\n", ffdc_line);
207 }
208 }
209 dev_warn(dev, "+-------------------------------------------+\n");
210 }
211 }
212
sbefifo_dump_ffdc(struct device * dev,const __be32 * ffdc,size_t ffdc_sz,bool internal)213 static void sbefifo_dump_ffdc(struct device *dev, const __be32 *ffdc,
214 size_t ffdc_sz, bool internal)
215 {
216 mutex_lock(&sbefifo_ffdc_mutex);
217 __sbefifo_dump_ffdc(dev, ffdc, ffdc_sz, internal);
218 mutex_unlock(&sbefifo_ffdc_mutex);
219 }
220
sbefifo_parse_status(struct device * dev,u16 cmd,__be32 * response,size_t resp_len,size_t * data_len)221 int sbefifo_parse_status(struct device *dev, u16 cmd, __be32 *response,
222 size_t resp_len, size_t *data_len)
223 {
224 u32 dh, s0, s1;
225 size_t ffdc_sz;
226
227 if (resp_len < 3) {
228 pr_debug("sbefifo: cmd %04x, response too small: %zd\n",
229 cmd, resp_len);
230 return -ENXIO;
231 }
232 dh = be32_to_cpu(response[resp_len - 1]);
233 if (dh > resp_len || dh < 3) {
234 dev_err(dev, "SBE cmd %02x:%02x status offset out of range: %d/%zd\n",
235 cmd >> 8, cmd & 0xff, dh, resp_len);
236 return -ENXIO;
237 }
238 s0 = be32_to_cpu(response[resp_len - dh]);
239 s1 = be32_to_cpu(response[resp_len - dh + 1]);
240 if (((s0 >> 16) != 0xC0DE) || ((s0 & 0xffff) != cmd)) {
241 dev_err(dev, "SBE cmd %02x:%02x, status signature invalid: 0x%08x 0x%08x\n",
242 cmd >> 8, cmd & 0xff, s0, s1);
243 return -ENXIO;
244 }
245 if (s1 != 0) {
246 ffdc_sz = dh - 3;
247 dev_warn(dev, "SBE error cmd %02x:%02x status=%04x:%04x\n",
248 cmd >> 8, cmd & 0xff, s1 >> 16, s1 & 0xffff);
249 if (ffdc_sz)
250 sbefifo_dump_ffdc(dev, &response[resp_len - dh + 2],
251 ffdc_sz, false);
252 }
253 if (data_len)
254 *data_len = resp_len - dh;
255
256 /*
257 * Primary status don't have the top bit set, so can't be confused with
258 * Linux negative error codes, so return the status word whole.
259 */
260 return s1;
261 }
262 EXPORT_SYMBOL_GPL(sbefifo_parse_status);
263
sbefifo_regr(struct sbefifo * sbefifo,int reg,u32 * word)264 static int sbefifo_regr(struct sbefifo *sbefifo, int reg, u32 *word)
265 {
266 __be32 raw_word;
267 int rc;
268
269 rc = fsi_device_read(sbefifo->fsi_dev, reg, &raw_word,
270 sizeof(raw_word));
271 if (rc)
272 return rc;
273
274 *word = be32_to_cpu(raw_word);
275
276 return 0;
277 }
278
sbefifo_regw(struct sbefifo * sbefifo,int reg,u32 word)279 static int sbefifo_regw(struct sbefifo *sbefifo, int reg, u32 word)
280 {
281 __be32 raw_word = cpu_to_be32(word);
282
283 return fsi_device_write(sbefifo->fsi_dev, reg, &raw_word,
284 sizeof(raw_word));
285 }
286
sbefifo_check_sbe_state(struct sbefifo * sbefifo)287 static int sbefifo_check_sbe_state(struct sbefifo *sbefifo)
288 {
289 __be32 raw_word;
290 u32 sbm;
291 int rc;
292
293 rc = fsi_slave_read(sbefifo->fsi_dev->slave, CFAM_GP_MBOX_SBM_ADDR,
294 &raw_word, sizeof(raw_word));
295 if (rc)
296 return rc;
297 sbm = be32_to_cpu(raw_word);
298
299 /* SBE booted at all ? */
300 if (!(sbm & CFAM_SBM_SBE_BOOTED))
301 return -ESHUTDOWN;
302
303 /* Check its state */
304 switch ((sbm & CFAM_SBM_SBE_STATE_MASK) >> CFAM_SBM_SBE_STATE_SHIFT) {
305 case SBE_STATE_UNKNOWN:
306 return -ESHUTDOWN;
307 case SBE_STATE_DMT:
308 return -EBUSY;
309 case SBE_STATE_IPLING:
310 case SBE_STATE_ISTEP:
311 case SBE_STATE_MPIPL:
312 case SBE_STATE_RUNTIME:
313 case SBE_STATE_DUMP: /* Not sure about that one */
314 break;
315 case SBE_STATE_FAILURE:
316 case SBE_STATE_QUIESCE:
317 return -ESHUTDOWN;
318 }
319
320 /* Is there async FFDC available ? Remember it */
321 if (sbm & CFAM_SBM_SBE_ASYNC_FFDC)
322 sbefifo->async_ffdc = true;
323
324 return 0;
325 }
326
327 /* Don't flip endianness of data to/from FIFO, just pass through. */
sbefifo_down_read(struct sbefifo * sbefifo,__be32 * word)328 static int sbefifo_down_read(struct sbefifo *sbefifo, __be32 *word)
329 {
330 return fsi_device_read(sbefifo->fsi_dev, SBEFIFO_DOWN, word,
331 sizeof(*word));
332 }
333
sbefifo_up_write(struct sbefifo * sbefifo,__be32 word)334 static int sbefifo_up_write(struct sbefifo *sbefifo, __be32 word)
335 {
336 return fsi_device_write(sbefifo->fsi_dev, SBEFIFO_UP, &word,
337 sizeof(word));
338 }
339
sbefifo_request_reset(struct sbefifo * sbefifo)340 static int sbefifo_request_reset(struct sbefifo *sbefifo)
341 {
342 struct device *dev = &sbefifo->fsi_dev->dev;
343 unsigned long end_time;
344 u32 status;
345 int rc;
346
347 dev_dbg(dev, "Requesting FIFO reset\n");
348
349 /* Mark broken first, will be cleared if reset succeeds */
350 sbefifo->broken = true;
351
352 /* Send reset request */
353 rc = sbefifo_regw(sbefifo, SBEFIFO_UP | SBEFIFO_REQ_RESET, 1);
354 if (rc) {
355 dev_err(dev, "Sending reset request failed, rc=%d\n", rc);
356 return rc;
357 }
358
359 /* Wait for it to complete */
360 end_time = jiffies + msecs_to_jiffies(SBEFIFO_RESET_TIMEOUT);
361 while (!time_after(jiffies, end_time)) {
362 rc = sbefifo_regr(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &status);
363 if (rc) {
364 dev_err(dev, "Failed to read UP fifo status during reset"
365 " , rc=%d\n", rc);
366 return rc;
367 }
368
369 if (!(status & SBEFIFO_STS_RESET_REQ)) {
370 dev_dbg(dev, "FIFO reset done\n");
371 sbefifo->broken = false;
372 return 0;
373 }
374
375 cond_resched();
376 }
377 dev_err(dev, "FIFO reset timed out\n");
378
379 return -ETIMEDOUT;
380 }
381
sbefifo_cleanup_hw(struct sbefifo * sbefifo)382 static int sbefifo_cleanup_hw(struct sbefifo *sbefifo)
383 {
384 struct device *dev = &sbefifo->fsi_dev->dev;
385 u32 up_status, down_status;
386 bool need_reset = false;
387 int rc;
388
389 rc = sbefifo_check_sbe_state(sbefifo);
390 if (rc) {
391 dev_dbg(dev, "SBE state=%d\n", rc);
392 return rc;
393 }
394
395 /* If broken, we don't need to look at status, go straight to reset */
396 if (sbefifo->broken)
397 goto do_reset;
398
399 rc = sbefifo_regr(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &up_status);
400 if (rc) {
401 dev_err(dev, "Cleanup: Reading UP status failed, rc=%d\n", rc);
402
403 /* Will try reset again on next attempt at using it */
404 sbefifo->broken = true;
405 return rc;
406 }
407
408 rc = sbefifo_regr(sbefifo, SBEFIFO_DOWN | SBEFIFO_STS, &down_status);
409 if (rc) {
410 dev_err(dev, "Cleanup: Reading DOWN status failed, rc=%d\n", rc);
411
412 /* Will try reset again on next attempt at using it */
413 sbefifo->broken = true;
414 return rc;
415 }
416
417 /* The FIFO already contains a reset request from the SBE ? */
418 if (down_status & SBEFIFO_STS_RESET_REQ) {
419 dev_info(dev, "Cleanup: FIFO reset request set, resetting\n");
420 rc = sbefifo_regw(sbefifo, SBEFIFO_DOWN, SBEFIFO_PERFORM_RESET);
421 if (rc) {
422 sbefifo->broken = true;
423 dev_err(dev, "Cleanup: Reset reg write failed, rc=%d\n", rc);
424 return rc;
425 }
426 sbefifo->broken = false;
427 return 0;
428 }
429
430 /* Parity error on either FIFO ? */
431 if ((up_status | down_status) & SBEFIFO_STS_PARITY_ERR)
432 need_reset = true;
433
434 /* Either FIFO not empty ? */
435 if (!((up_status & down_status) & SBEFIFO_STS_EMPTY))
436 need_reset = true;
437
438 if (!need_reset)
439 return 0;
440
441 dev_info(dev, "Cleanup: FIFO not clean (up=0x%08x down=0x%08x)\n",
442 up_status, down_status);
443
444 do_reset:
445
446 /* Mark broken, will be cleared if/when reset succeeds */
447 return sbefifo_request_reset(sbefifo);
448 }
449
sbefifo_wait(struct sbefifo * sbefifo,bool up,u32 * status,unsigned long timeout)450 static int sbefifo_wait(struct sbefifo *sbefifo, bool up,
451 u32 *status, unsigned long timeout)
452 {
453 struct device *dev = &sbefifo->fsi_dev->dev;
454 unsigned long end_time;
455 bool ready = false;
456 u32 addr, sts = 0;
457 int rc;
458
459 dev_vdbg(dev, "Wait on %s fifo...\n", up ? "up" : "down");
460
461 addr = (up ? SBEFIFO_UP : SBEFIFO_DOWN) | SBEFIFO_STS;
462
463 end_time = jiffies + timeout;
464 while (!time_after(jiffies, end_time)) {
465 cond_resched();
466 rc = sbefifo_regr(sbefifo, addr, &sts);
467 if (rc < 0) {
468 dev_err(dev, "FSI error %d reading status register\n", rc);
469 return rc;
470 }
471 if (!up && sbefifo_parity_err(sts)) {
472 dev_err(dev, "Parity error in DOWN FIFO\n");
473 return -ENXIO;
474 }
475 ready = !(up ? sbefifo_full(sts) : sbefifo_empty(sts));
476 if (ready)
477 break;
478 }
479 if (!ready) {
480 sysfs_notify(&sbefifo->dev.kobj, NULL, dev_attr_timeout.attr.name);
481 sbefifo->timed_out = true;
482 dev_err(dev, "%s FIFO Timeout (%u ms)! status=%08x\n",
483 up ? "UP" : "DOWN", jiffies_to_msecs(timeout), sts);
484 return -ETIMEDOUT;
485 }
486 dev_vdbg(dev, "End of wait status: %08x\n", sts);
487
488 sbefifo->timed_out = false;
489 *status = sts;
490
491 return 0;
492 }
493
sbefifo_send_command(struct sbefifo * sbefifo,const __be32 * command,size_t cmd_len)494 static int sbefifo_send_command(struct sbefifo *sbefifo,
495 const __be32 *command, size_t cmd_len)
496 {
497 struct device *dev = &sbefifo->fsi_dev->dev;
498 size_t len, chunk, vacant = 0, remaining = cmd_len;
499 unsigned long timeout;
500 u32 status;
501 int rc;
502
503 dev_dbg(dev, "sending command (%zd words, cmd=%04x)\n",
504 cmd_len, be32_to_cpu(command[1]));
505
506 /* As long as there's something to send */
507 timeout = msecs_to_jiffies(SBEFIFO_TIMEOUT_START_CMD);
508 while (remaining) {
509 /* Wait for room in the FIFO */
510 rc = sbefifo_wait(sbefifo, true, &status, timeout);
511 if (rc < 0)
512 return rc;
513 timeout = msecs_to_jiffies(sbefifo->timeout_in_cmd_ms);
514
515 vacant = sbefifo_vacant(status);
516 len = chunk = min(vacant, remaining);
517
518 dev_vdbg(dev, " status=%08x vacant=%zd chunk=%zd\n",
519 status, vacant, chunk);
520
521 /* Write as much as we can */
522 while (len--) {
523 rc = sbefifo_up_write(sbefifo, *(command++));
524 if (rc) {
525 dev_err(dev, "FSI error %d writing UP FIFO\n", rc);
526 return rc;
527 }
528 }
529 remaining -= chunk;
530 vacant -= chunk;
531 }
532
533 /* If there's no room left, wait for some to write EOT */
534 if (!vacant) {
535 rc = sbefifo_wait(sbefifo, true, &status, timeout);
536 if (rc)
537 return rc;
538 }
539
540 /* Send an EOT */
541 rc = sbefifo_regw(sbefifo, SBEFIFO_UP | SBEFIFO_EOT_RAISE, 0);
542 if (rc)
543 dev_err(dev, "FSI error %d writing EOT\n", rc);
544 return rc;
545 }
546
sbefifo_read_response(struct sbefifo * sbefifo,struct iov_iter * response)547 static int sbefifo_read_response(struct sbefifo *sbefifo, struct iov_iter *response)
548 {
549 struct device *dev = &sbefifo->fsi_dev->dev;
550 u32 status, eot_set;
551 unsigned long timeout;
552 bool overflow = false;
553 __be32 data;
554 size_t len;
555 int rc;
556
557 dev_dbg(dev, "reading response, buflen = %zd\n", iov_iter_count(response));
558
559 timeout = msecs_to_jiffies(sbefifo->timeout_start_rsp_ms);
560 for (;;) {
561 /* Grab FIFO status (this will handle parity errors) */
562 rc = sbefifo_wait(sbefifo, false, &status, timeout);
563 if (rc < 0) {
564 dev_dbg(dev, "timeout waiting (%u ms)\n", jiffies_to_msecs(timeout));
565 return rc;
566 }
567 timeout = msecs_to_jiffies(SBEFIFO_TIMEOUT_IN_RSP);
568
569 /* Decode status */
570 len = sbefifo_populated(status);
571 eot_set = sbefifo_eot_set(status);
572
573 dev_dbg(dev, " chunk size %zd eot_set=0x%x\n", len, eot_set);
574
575 /* Go through the chunk */
576 while(len--) {
577 /* Read the data */
578 rc = sbefifo_down_read(sbefifo, &data);
579 if (rc < 0)
580 return rc;
581
582 /* Was it an EOT ? */
583 if (eot_set & 0x80) {
584 /*
585 * There should be nothing else in the FIFO,
586 * if there is, mark broken, this will force
587 * a reset on next use, but don't fail the
588 * command.
589 */
590 if (len) {
591 dev_warn(dev, "FIFO read hit"
592 " EOT with still %zd data\n",
593 len);
594 sbefifo->broken = true;
595 }
596
597 /* We are done */
598 rc = sbefifo_regw(sbefifo,
599 SBEFIFO_DOWN | SBEFIFO_EOT_ACK, 0);
600
601 /*
602 * If that write fail, still complete the request but mark
603 * the fifo as broken for subsequent reset (not much else
604 * we can do here).
605 */
606 if (rc) {
607 dev_err(dev, "FSI error %d ack'ing EOT\n", rc);
608 sbefifo->broken = true;
609 }
610
611 /* Tell whether we overflowed */
612 return overflow ? -EOVERFLOW : 0;
613 }
614
615 /* Store it if there is room */
616 if (iov_iter_count(response) >= sizeof(__be32)) {
617 if (copy_to_iter(&data, sizeof(__be32), response) < sizeof(__be32))
618 return -EFAULT;
619 } else {
620 dev_vdbg(dev, "Response overflowed !\n");
621
622 overflow = true;
623 }
624
625 /* Next EOT bit */
626 eot_set <<= 1;
627 }
628 }
629 /* Shouldn't happen */
630 return -EIO;
631 }
632
sbefifo_do_command(struct sbefifo * sbefifo,const __be32 * command,size_t cmd_len,struct iov_iter * response)633 static int sbefifo_do_command(struct sbefifo *sbefifo,
634 const __be32 *command, size_t cmd_len,
635 struct iov_iter *response)
636 {
637 /* Try sending the command */
638 int rc = sbefifo_send_command(sbefifo, command, cmd_len);
639 if (rc)
640 return rc;
641
642 /* Now, get the response */
643 return sbefifo_read_response(sbefifo, response);
644 }
645
sbefifo_collect_async_ffdc(struct sbefifo * sbefifo)646 static void sbefifo_collect_async_ffdc(struct sbefifo *sbefifo)
647 {
648 struct device *dev = &sbefifo->fsi_dev->dev;
649 struct iov_iter ffdc_iter;
650 struct kvec ffdc_iov;
651 __be32 *ffdc;
652 size_t ffdc_sz;
653 __be32 cmd[2];
654 int rc;
655
656 sbefifo->async_ffdc = false;
657 ffdc = vmalloc(SBEFIFO_MAX_FFDC_SIZE);
658 if (!ffdc) {
659 dev_err(dev, "Failed to allocate SBE FFDC buffer\n");
660 return;
661 }
662 ffdc_iov.iov_base = ffdc;
663 ffdc_iov.iov_len = SBEFIFO_MAX_FFDC_SIZE;
664 iov_iter_kvec(&ffdc_iter, ITER_DEST, &ffdc_iov, 1, SBEFIFO_MAX_FFDC_SIZE);
665 cmd[0] = cpu_to_be32(2);
666 cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_SBE_FFDC);
667 rc = sbefifo_do_command(sbefifo, cmd, 2, &ffdc_iter);
668 if (rc != 0) {
669 dev_err(dev, "Error %d retrieving SBE FFDC\n", rc);
670 goto bail;
671 }
672 ffdc_sz = SBEFIFO_MAX_FFDC_SIZE - iov_iter_count(&ffdc_iter);
673 ffdc_sz /= sizeof(__be32);
674 rc = sbefifo_parse_status(dev, SBEFIFO_CMD_GET_SBE_FFDC, ffdc,
675 ffdc_sz, &ffdc_sz);
676 if (rc != 0) {
677 dev_err(dev, "Error %d decoding SBE FFDC\n", rc);
678 goto bail;
679 }
680 if (ffdc_sz > 0)
681 sbefifo_dump_ffdc(dev, ffdc, ffdc_sz, true);
682 bail:
683 vfree(ffdc);
684
685 }
686
__sbefifo_submit(struct sbefifo * sbefifo,const __be32 * command,size_t cmd_len,struct iov_iter * response)687 static int __sbefifo_submit(struct sbefifo *sbefifo,
688 const __be32 *command, size_t cmd_len,
689 struct iov_iter *response)
690 {
691 struct device *dev = &sbefifo->fsi_dev->dev;
692 int rc;
693
694 if (sbefifo->dead)
695 return -ENODEV;
696
697 if (cmd_len < 2 || be32_to_cpu(command[0]) != cmd_len) {
698 dev_vdbg(dev, "Invalid command len %zd (header: %d)\n",
699 cmd_len, be32_to_cpu(command[0]));
700 return -EINVAL;
701 }
702
703 /* First ensure the HW is in a clean state */
704 rc = sbefifo_cleanup_hw(sbefifo);
705 if (rc)
706 return rc;
707
708 /* Look for async FFDC first if any */
709 if (sbefifo->async_ffdc)
710 sbefifo_collect_async_ffdc(sbefifo);
711
712 rc = sbefifo_do_command(sbefifo, command, cmd_len, response);
713 if (rc != 0 && rc != -EOVERFLOW)
714 goto fail;
715 return rc;
716 fail:
717 /*
718 * On failure, attempt a reset. Ignore the result, it will mark
719 * the fifo broken if the reset fails
720 */
721 sbefifo_request_reset(sbefifo);
722
723 /* Return original error */
724 return rc;
725 }
726
727 /**
728 * sbefifo_submit() - Submit and SBE fifo command and receive response
729 * @dev: The sbefifo device
730 * @command: The raw command data
731 * @cmd_len: The command size (in 32-bit words)
732 * @response: The output response buffer
733 * @resp_len: In: Response buffer size, Out: Response size
734 *
735 * This will perform the entire operation. If the response buffer
736 * overflows, returns -EOVERFLOW
737 */
sbefifo_submit(struct device * dev,const __be32 * command,size_t cmd_len,__be32 * response,size_t * resp_len)738 int sbefifo_submit(struct device *dev, const __be32 *command, size_t cmd_len,
739 __be32 *response, size_t *resp_len)
740 {
741 struct sbefifo *sbefifo;
742 struct iov_iter resp_iter;
743 struct kvec resp_iov;
744 size_t rbytes;
745 int rc;
746
747 if (!dev)
748 return -ENODEV;
749 sbefifo = dev_get_drvdata(dev);
750 if (!sbefifo)
751 return -ENODEV;
752 if (WARN_ON_ONCE(sbefifo->magic != SBEFIFO_MAGIC))
753 return -ENODEV;
754 if (!resp_len || !command || !response)
755 return -EINVAL;
756
757 /* Prepare iov iterator */
758 rbytes = (*resp_len) * sizeof(__be32);
759 resp_iov.iov_base = response;
760 resp_iov.iov_len = rbytes;
761 iov_iter_kvec(&resp_iter, ITER_DEST, &resp_iov, 1, rbytes);
762
763 /* Perform the command */
764 rc = mutex_lock_interruptible(&sbefifo->lock);
765 if (rc)
766 return rc;
767 rc = __sbefifo_submit(sbefifo, command, cmd_len, &resp_iter);
768 mutex_unlock(&sbefifo->lock);
769
770 /* Extract the response length */
771 rbytes -= iov_iter_count(&resp_iter);
772 *resp_len = rbytes / sizeof(__be32);
773
774 return rc;
775 }
776 EXPORT_SYMBOL_GPL(sbefifo_submit);
777
778 /*
779 * Char device interface
780 */
781
sbefifo_release_command(struct sbefifo_user * user)782 static void sbefifo_release_command(struct sbefifo_user *user)
783 {
784 if (is_vmalloc_addr(user->pending_cmd))
785 vfree(user->pending_cmd);
786 user->pending_cmd = NULL;
787 user->pending_len = 0;
788 }
789
sbefifo_user_open(struct inode * inode,struct file * file)790 static int sbefifo_user_open(struct inode *inode, struct file *file)
791 {
792 struct sbefifo *sbefifo = container_of(inode->i_cdev, struct sbefifo, cdev);
793 struct sbefifo_user *user;
794
795 user = kzalloc(sizeof(struct sbefifo_user), GFP_KERNEL);
796 if (!user)
797 return -ENOMEM;
798
799 file->private_data = user;
800 user->sbefifo = sbefifo;
801 user->cmd_page = (void *)__get_free_page(GFP_KERNEL);
802 if (!user->cmd_page) {
803 kfree(user);
804 return -ENOMEM;
805 }
806 mutex_init(&user->file_lock);
807 user->cmd_timeout_ms = SBEFIFO_TIMEOUT_IN_CMD;
808 user->read_timeout_ms = SBEFIFO_TIMEOUT_START_RSP;
809
810 return 0;
811 }
812
sbefifo_user_read(struct file * file,char __user * buf,size_t len,loff_t * offset)813 static ssize_t sbefifo_user_read(struct file *file, char __user *buf,
814 size_t len, loff_t *offset)
815 {
816 struct sbefifo_user *user = file->private_data;
817 struct sbefifo *sbefifo;
818 struct iov_iter resp_iter;
819 struct iovec resp_iov;
820 size_t cmd_len;
821 int rc;
822
823 if (!user)
824 return -EINVAL;
825 sbefifo = user->sbefifo;
826 if (len & 3)
827 return -EINVAL;
828
829 mutex_lock(&user->file_lock);
830
831 /* Cronus relies on -EAGAIN after a short read */
832 if (user->pending_len == 0) {
833 rc = -EAGAIN;
834 goto bail;
835 }
836 if (user->pending_len < 8) {
837 rc = -EINVAL;
838 goto bail;
839 }
840 cmd_len = user->pending_len >> 2;
841
842 /* Prepare iov iterator */
843 resp_iov.iov_base = buf;
844 resp_iov.iov_len = len;
845 iov_iter_init(&resp_iter, ITER_DEST, &resp_iov, 1, len);
846
847 /* Perform the command */
848 rc = mutex_lock_interruptible(&sbefifo->lock);
849 if (rc)
850 goto bail;
851 sbefifo->timeout_in_cmd_ms = user->cmd_timeout_ms;
852 sbefifo->timeout_start_rsp_ms = user->read_timeout_ms;
853 rc = __sbefifo_submit(sbefifo, user->pending_cmd, cmd_len, &resp_iter);
854 sbefifo->timeout_start_rsp_ms = SBEFIFO_TIMEOUT_START_RSP;
855 sbefifo->timeout_in_cmd_ms = SBEFIFO_TIMEOUT_IN_CMD;
856 mutex_unlock(&sbefifo->lock);
857 if (rc < 0)
858 goto bail;
859
860 /* Extract the response length */
861 rc = len - iov_iter_count(&resp_iter);
862 bail:
863 sbefifo_release_command(user);
864 mutex_unlock(&user->file_lock);
865 return rc;
866 }
867
sbefifo_user_write(struct file * file,const char __user * buf,size_t len,loff_t * offset)868 static ssize_t sbefifo_user_write(struct file *file, const char __user *buf,
869 size_t len, loff_t *offset)
870 {
871 struct sbefifo_user *user = file->private_data;
872 struct sbefifo *sbefifo;
873 int rc = len;
874
875 if (!user)
876 return -EINVAL;
877 sbefifo = user->sbefifo;
878 if (len > SBEFIFO_MAX_USER_CMD_LEN)
879 return -EINVAL;
880 if (len & 3)
881 return -EINVAL;
882
883 mutex_lock(&user->file_lock);
884
885 /* Can we use the pre-allocate buffer ? If not, allocate */
886 if (len <= PAGE_SIZE)
887 user->pending_cmd = user->cmd_page;
888 else
889 user->pending_cmd = vmalloc(len);
890 if (!user->pending_cmd) {
891 rc = -ENOMEM;
892 goto bail;
893 }
894
895 /* Copy the command into the staging buffer */
896 if (copy_from_user(user->pending_cmd, buf, len)) {
897 rc = -EFAULT;
898 goto bail;
899 }
900
901 /* Check for the magic reset command */
902 if (len == 4 && be32_to_cpu(*(__be32 *)user->pending_cmd) ==
903 SBEFIFO_RESET_MAGIC) {
904
905 /* Clear out any pending command */
906 user->pending_len = 0;
907
908 /* Trigger reset request */
909 rc = mutex_lock_interruptible(&sbefifo->lock);
910 if (rc)
911 goto bail;
912 rc = sbefifo_request_reset(user->sbefifo);
913 mutex_unlock(&sbefifo->lock);
914 if (rc == 0)
915 rc = 4;
916 goto bail;
917 }
918
919 /* Update the staging buffer size */
920 user->pending_len = len;
921 bail:
922 if (!user->pending_len)
923 sbefifo_release_command(user);
924
925 mutex_unlock(&user->file_lock);
926
927 /* And that's it, we'll issue the command on a read */
928 return rc;
929 }
930
sbefifo_user_release(struct inode * inode,struct file * file)931 static int sbefifo_user_release(struct inode *inode, struct file *file)
932 {
933 struct sbefifo_user *user = file->private_data;
934
935 if (!user)
936 return -EINVAL;
937
938 sbefifo_release_command(user);
939 free_page((unsigned long)user->cmd_page);
940 kfree(user);
941
942 return 0;
943 }
944
sbefifo_cmd_timeout(struct sbefifo_user * user,void __user * argp)945 static int sbefifo_cmd_timeout(struct sbefifo_user *user, void __user *argp)
946 {
947 struct device *dev = &user->sbefifo->dev;
948 u32 timeout;
949
950 if (get_user(timeout, (__u32 __user *)argp))
951 return -EFAULT;
952
953 if (timeout == 0) {
954 user->cmd_timeout_ms = SBEFIFO_TIMEOUT_IN_CMD;
955 dev_dbg(dev, "Command timeout reset to %us\n", user->cmd_timeout_ms / 1000);
956 return 0;
957 }
958
959 user->cmd_timeout_ms = timeout * 1000; /* user timeout is in sec */
960 dev_dbg(dev, "Command timeout set to %us\n", timeout);
961 return 0;
962 }
963
sbefifo_read_timeout(struct sbefifo_user * user,void __user * argp)964 static int sbefifo_read_timeout(struct sbefifo_user *user, void __user *argp)
965 {
966 struct device *dev = &user->sbefifo->dev;
967 u32 timeout;
968
969 if (get_user(timeout, (__u32 __user *)argp))
970 return -EFAULT;
971
972 if (timeout == 0) {
973 user->read_timeout_ms = SBEFIFO_TIMEOUT_START_RSP;
974 dev_dbg(dev, "Timeout reset to %us\n", user->read_timeout_ms / 1000);
975 return 0;
976 }
977
978 user->read_timeout_ms = timeout * 1000; /* user timeout is in sec */
979 dev_dbg(dev, "Timeout set to %us\n", timeout);
980 return 0;
981 }
982
sbefifo_user_ioctl(struct file * file,unsigned int cmd,unsigned long arg)983 static long sbefifo_user_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
984 {
985 struct sbefifo_user *user = file->private_data;
986 int rc = -ENOTTY;
987
988 if (!user)
989 return -EINVAL;
990
991 mutex_lock(&user->file_lock);
992 switch (cmd) {
993 case FSI_SBEFIFO_CMD_TIMEOUT_SECONDS:
994 rc = sbefifo_cmd_timeout(user, (void __user *)arg);
995 break;
996 case FSI_SBEFIFO_READ_TIMEOUT_SECONDS:
997 rc = sbefifo_read_timeout(user, (void __user *)arg);
998 break;
999 }
1000 mutex_unlock(&user->file_lock);
1001 return rc;
1002 }
1003
1004 static const struct file_operations sbefifo_fops = {
1005 .owner = THIS_MODULE,
1006 .open = sbefifo_user_open,
1007 .read = sbefifo_user_read,
1008 .write = sbefifo_user_write,
1009 .release = sbefifo_user_release,
1010 .unlocked_ioctl = sbefifo_user_ioctl,
1011 };
1012
sbefifo_free(struct device * dev)1013 static void sbefifo_free(struct device *dev)
1014 {
1015 struct sbefifo *sbefifo = container_of(dev, struct sbefifo, dev);
1016
1017 put_device(&sbefifo->fsi_dev->dev);
1018 kfree(sbefifo);
1019 }
1020
1021 /*
1022 * Probe/remove
1023 */
1024
sbefifo_probe(struct device * dev)1025 static int sbefifo_probe(struct device *dev)
1026 {
1027 struct fsi_device *fsi_dev = to_fsi_dev(dev);
1028 struct sbefifo *sbefifo;
1029 struct device_node *np;
1030 struct platform_device *child;
1031 char child_name[32];
1032 int rc, didx, child_idx = 0;
1033
1034 dev_dbg(dev, "Found sbefifo device\n");
1035
1036 sbefifo = kzalloc(sizeof(*sbefifo), GFP_KERNEL);
1037 if (!sbefifo)
1038 return -ENOMEM;
1039
1040 /* Grab a reference to the device (parent of our cdev), we'll drop it later */
1041 if (!get_device(dev)) {
1042 kfree(sbefifo);
1043 return -ENODEV;
1044 }
1045
1046 sbefifo->magic = SBEFIFO_MAGIC;
1047 sbefifo->fsi_dev = fsi_dev;
1048 dev_set_drvdata(dev, sbefifo);
1049 mutex_init(&sbefifo->lock);
1050 sbefifo->timeout_in_cmd_ms = SBEFIFO_TIMEOUT_IN_CMD;
1051 sbefifo->timeout_start_rsp_ms = SBEFIFO_TIMEOUT_START_RSP;
1052
1053 /* Create chardev for userspace access */
1054 sbefifo->dev.type = &fsi_cdev_type;
1055 sbefifo->dev.parent = dev;
1056 sbefifo->dev.release = sbefifo_free;
1057 device_initialize(&sbefifo->dev);
1058
1059 /* Allocate a minor in the FSI space */
1060 rc = fsi_get_new_minor(fsi_dev, fsi_dev_sbefifo, &sbefifo->dev.devt, &didx);
1061 if (rc)
1062 goto err;
1063
1064 dev_set_name(&sbefifo->dev, "sbefifo%d", didx);
1065 cdev_init(&sbefifo->cdev, &sbefifo_fops);
1066 rc = cdev_device_add(&sbefifo->cdev, &sbefifo->dev);
1067 if (rc) {
1068 dev_err(dev, "Error %d creating char device %s\n",
1069 rc, dev_name(&sbefifo->dev));
1070 goto err_free_minor;
1071 }
1072
1073 /* Create platform devs for dts child nodes (occ, etc) */
1074 for_each_available_child_of_node(dev->of_node, np) {
1075 snprintf(child_name, sizeof(child_name), "%s-dev%d",
1076 dev_name(&sbefifo->dev), child_idx++);
1077 child = of_platform_device_create(np, child_name, dev);
1078 if (!child)
1079 dev_warn(dev, "failed to create child %s dev\n",
1080 child_name);
1081 }
1082
1083 device_create_file(&sbefifo->dev, &dev_attr_timeout);
1084
1085 return 0;
1086 err_free_minor:
1087 fsi_free_minor(sbefifo->dev.devt);
1088 err:
1089 put_device(&sbefifo->dev);
1090 return rc;
1091 }
1092
sbefifo_unregister_child(struct device * dev,void * data)1093 static int sbefifo_unregister_child(struct device *dev, void *data)
1094 {
1095 struct platform_device *child = to_platform_device(dev);
1096
1097 of_device_unregister(child);
1098 if (dev->of_node)
1099 of_node_clear_flag(dev->of_node, OF_POPULATED);
1100
1101 return 0;
1102 }
1103
sbefifo_remove(struct device * dev)1104 static int sbefifo_remove(struct device *dev)
1105 {
1106 struct sbefifo *sbefifo = dev_get_drvdata(dev);
1107
1108 dev_dbg(dev, "Removing sbefifo device...\n");
1109
1110 device_remove_file(&sbefifo->dev, &dev_attr_timeout);
1111
1112 mutex_lock(&sbefifo->lock);
1113 sbefifo->dead = true;
1114 mutex_unlock(&sbefifo->lock);
1115
1116 cdev_device_del(&sbefifo->cdev, &sbefifo->dev);
1117 fsi_free_minor(sbefifo->dev.devt);
1118 device_for_each_child(dev, NULL, sbefifo_unregister_child);
1119 put_device(&sbefifo->dev);
1120
1121 return 0;
1122 }
1123
1124 static const struct fsi_device_id sbefifo_ids[] = {
1125 {
1126 .engine_type = FSI_ENGID_SBE,
1127 .version = FSI_VERSION_ANY,
1128 },
1129 { 0 }
1130 };
1131
1132 static struct fsi_driver sbefifo_drv = {
1133 .id_table = sbefifo_ids,
1134 .drv = {
1135 .name = DEVICE_NAME,
1136 .bus = &fsi_bus_type,
1137 .probe = sbefifo_probe,
1138 .remove = sbefifo_remove,
1139 }
1140 };
1141
sbefifo_init(void)1142 static int sbefifo_init(void)
1143 {
1144 return fsi_driver_register(&sbefifo_drv);
1145 }
1146
sbefifo_exit(void)1147 static void sbefifo_exit(void)
1148 {
1149 fsi_driver_unregister(&sbefifo_drv);
1150 }
1151
1152 module_init(sbefifo_init);
1153 module_exit(sbefifo_exit);
1154 MODULE_LICENSE("GPL");
1155 MODULE_AUTHOR("Brad Bishop <bradleyb@fuzziesquirrel.com>");
1156 MODULE_AUTHOR("Eddie James <eajames@linux.vnet.ibm.com>");
1157 MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
1158 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
1159 MODULE_DESCRIPTION("Linux device interface to the POWER Self Boot Engine");
1160