1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * uvc_video.c -- USB Video Class driver - Video handling
4 *
5 * Copyright (C) 2005-2010
6 * Laurent Pinchart (laurent.pinchart@ideasonboard.com)
7 */
8
9 #include <linux/dma-mapping.h>
10 #include <linux/highmem.h>
11 #include <linux/kernel.h>
12 #include <linux/list.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/usb.h>
16 #include <linux/usb/hcd.h>
17 #include <linux/videodev2.h>
18 #include <linux/vmalloc.h>
19 #include <linux/wait.h>
20 #include <linux/atomic.h>
21 #include <asm/unaligned.h>
22
23 #include <media/v4l2-common.h>
24
25 #include "uvcvideo.h"
26
27 /* ------------------------------------------------------------------------
28 * UVC Controls
29 */
30
__uvc_query_ctrl(struct uvc_device * dev,u8 query,u8 unit,u8 intfnum,u8 cs,void * data,u16 size,int timeout)31 static int __uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
32 u8 intfnum, u8 cs, void *data, u16 size,
33 int timeout)
34 {
35 u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
36 unsigned int pipe;
37
38 pipe = (query & 0x80) ? usb_rcvctrlpipe(dev->udev, 0)
39 : usb_sndctrlpipe(dev->udev, 0);
40 type |= (query & 0x80) ? USB_DIR_IN : USB_DIR_OUT;
41
42 return usb_control_msg(dev->udev, pipe, query, type, cs << 8,
43 unit << 8 | intfnum, data, size, timeout);
44 }
45
uvc_query_name(u8 query)46 static const char *uvc_query_name(u8 query)
47 {
48 switch (query) {
49 case UVC_SET_CUR:
50 return "SET_CUR";
51 case UVC_GET_CUR:
52 return "GET_CUR";
53 case UVC_GET_MIN:
54 return "GET_MIN";
55 case UVC_GET_MAX:
56 return "GET_MAX";
57 case UVC_GET_RES:
58 return "GET_RES";
59 case UVC_GET_LEN:
60 return "GET_LEN";
61 case UVC_GET_INFO:
62 return "GET_INFO";
63 case UVC_GET_DEF:
64 return "GET_DEF";
65 default:
66 return "<invalid>";
67 }
68 }
69
uvc_query_ctrl(struct uvc_device * dev,u8 query,u8 unit,u8 intfnum,u8 cs,void * data,u16 size)70 int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
71 u8 intfnum, u8 cs, void *data, u16 size)
72 {
73 int ret;
74 u8 error;
75 u8 tmp;
76
77 ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size,
78 UVC_CTRL_CONTROL_TIMEOUT);
79 if (likely(ret == size))
80 return 0;
81
82 dev_err(&dev->udev->dev,
83 "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",
84 uvc_query_name(query), cs, unit, ret, size);
85
86 if (ret != -EPIPE)
87 return ret;
88
89 tmp = *(u8 *)data;
90
91 ret = __uvc_query_ctrl(dev, UVC_GET_CUR, 0, intfnum,
92 UVC_VC_REQUEST_ERROR_CODE_CONTROL, data, 1,
93 UVC_CTRL_CONTROL_TIMEOUT);
94
95 error = *(u8 *)data;
96 *(u8 *)data = tmp;
97
98 if (ret != 1)
99 return ret < 0 ? ret : -EPIPE;
100
101 uvc_dbg(dev, CONTROL, "Control error %u\n", error);
102
103 switch (error) {
104 case 0:
105 /* Cannot happen - we received a STALL */
106 return -EPIPE;
107 case 1: /* Not ready */
108 return -EBUSY;
109 case 2: /* Wrong state */
110 return -EILSEQ;
111 case 3: /* Power */
112 return -EREMOTE;
113 case 4: /* Out of range */
114 return -ERANGE;
115 case 5: /* Invalid unit */
116 case 6: /* Invalid control */
117 case 7: /* Invalid Request */
118 case 8: /* Invalid value within range */
119 return -EINVAL;
120 default: /* reserved or unknown */
121 break;
122 }
123
124 return -EPIPE;
125 }
126
uvc_fixup_video_ctrl(struct uvc_streaming * stream,struct uvc_streaming_control * ctrl)127 static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
128 struct uvc_streaming_control *ctrl)
129 {
130 struct uvc_format *format = NULL;
131 struct uvc_frame *frame = NULL;
132 unsigned int i;
133
134 for (i = 0; i < stream->nformats; ++i) {
135 if (stream->format[i].index == ctrl->bFormatIndex) {
136 format = &stream->format[i];
137 break;
138 }
139 }
140
141 if (format == NULL)
142 return;
143
144 for (i = 0; i < format->nframes; ++i) {
145 if (format->frame[i].bFrameIndex == ctrl->bFrameIndex) {
146 frame = &format->frame[i];
147 break;
148 }
149 }
150
151 if (frame == NULL)
152 return;
153
154 if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) ||
155 (ctrl->dwMaxVideoFrameSize == 0 &&
156 stream->dev->uvc_version < 0x0110))
157 ctrl->dwMaxVideoFrameSize =
158 frame->dwMaxVideoFrameBufferSize;
159
160 /* The "TOSHIBA Web Camera - 5M" Chicony device (04f2:b50b) seems to
161 * compute the bandwidth on 16 bits and erroneously sign-extend it to
162 * 32 bits, resulting in a huge bandwidth value. Detect and fix that
163 * condition by setting the 16 MSBs to 0 when they're all equal to 1.
164 */
165 if ((ctrl->dwMaxPayloadTransferSize & 0xffff0000) == 0xffff0000)
166 ctrl->dwMaxPayloadTransferSize &= ~0xffff0000;
167
168 if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) &&
169 stream->dev->quirks & UVC_QUIRK_FIX_BANDWIDTH &&
170 stream->intf->num_altsetting > 1) {
171 u32 interval;
172 u32 bandwidth;
173
174 interval = (ctrl->dwFrameInterval > 100000)
175 ? ctrl->dwFrameInterval
176 : frame->dwFrameInterval[0];
177
178 /* Compute a bandwidth estimation by multiplying the frame
179 * size by the number of video frames per second, divide the
180 * result by the number of USB frames (or micro-frames for
181 * high-speed devices) per second and add the UVC header size
182 * (assumed to be 12 bytes long).
183 */
184 bandwidth = frame->wWidth * frame->wHeight / 8 * format->bpp;
185 bandwidth *= 10000000 / interval + 1;
186 bandwidth /= 1000;
187 if (stream->dev->udev->speed == USB_SPEED_HIGH)
188 bandwidth /= 8;
189 bandwidth += 12;
190
191 /* The bandwidth estimate is too low for many cameras. Don't use
192 * maximum packet sizes lower than 1024 bytes to try and work
193 * around the problem. According to measurements done on two
194 * different camera models, the value is high enough to get most
195 * resolutions working while not preventing two simultaneous
196 * VGA streams at 15 fps.
197 */
198 bandwidth = max_t(u32, bandwidth, 1024);
199
200 ctrl->dwMaxPayloadTransferSize = bandwidth;
201 }
202 }
203
uvc_video_ctrl_size(struct uvc_streaming * stream)204 static size_t uvc_video_ctrl_size(struct uvc_streaming *stream)
205 {
206 /*
207 * Return the size of the video probe and commit controls, which depends
208 * on the protocol version.
209 */
210 if (stream->dev->uvc_version < 0x0110)
211 return 26;
212 else if (stream->dev->uvc_version < 0x0150)
213 return 34;
214 else
215 return 48;
216 }
217
uvc_get_video_ctrl(struct uvc_streaming * stream,struct uvc_streaming_control * ctrl,int probe,u8 query)218 static int uvc_get_video_ctrl(struct uvc_streaming *stream,
219 struct uvc_streaming_control *ctrl, int probe, u8 query)
220 {
221 u16 size = uvc_video_ctrl_size(stream);
222 u8 *data;
223 int ret;
224
225 if ((stream->dev->quirks & UVC_QUIRK_PROBE_DEF) &&
226 query == UVC_GET_DEF)
227 return -EIO;
228
229 data = kmalloc(size, GFP_KERNEL);
230 if (data == NULL)
231 return -ENOMEM;
232
233 ret = __uvc_query_ctrl(stream->dev, query, 0, stream->intfnum,
234 probe ? UVC_VS_PROBE_CONTROL : UVC_VS_COMMIT_CONTROL, data,
235 size, uvc_timeout_param);
236
237 if ((query == UVC_GET_MIN || query == UVC_GET_MAX) && ret == 2) {
238 /* Some cameras, mostly based on Bison Electronics chipsets,
239 * answer a GET_MIN or GET_MAX request with the wCompQuality
240 * field only.
241 */
242 uvc_warn_once(stream->dev, UVC_WARN_MINMAX, "UVC non "
243 "compliance - GET_MIN/MAX(PROBE) incorrectly "
244 "supported. Enabling workaround.\n");
245 memset(ctrl, 0, sizeof(*ctrl));
246 ctrl->wCompQuality = le16_to_cpup((__le16 *)data);
247 ret = 0;
248 goto out;
249 } else if (query == UVC_GET_DEF && probe == 1 && ret != size) {
250 /* Many cameras don't support the GET_DEF request on their
251 * video probe control. Warn once and return, the caller will
252 * fall back to GET_CUR.
253 */
254 uvc_warn_once(stream->dev, UVC_WARN_PROBE_DEF, "UVC non "
255 "compliance - GET_DEF(PROBE) not supported. "
256 "Enabling workaround.\n");
257 ret = -EIO;
258 goto out;
259 } else if (ret != size) {
260 dev_err(&stream->intf->dev,
261 "Failed to query (%u) UVC %s control : %d (exp. %u).\n",
262 query, probe ? "probe" : "commit", ret, size);
263 ret = -EIO;
264 goto out;
265 }
266
267 ctrl->bmHint = le16_to_cpup((__le16 *)&data[0]);
268 ctrl->bFormatIndex = data[2];
269 ctrl->bFrameIndex = data[3];
270 ctrl->dwFrameInterval = le32_to_cpup((__le32 *)&data[4]);
271 ctrl->wKeyFrameRate = le16_to_cpup((__le16 *)&data[8]);
272 ctrl->wPFrameRate = le16_to_cpup((__le16 *)&data[10]);
273 ctrl->wCompQuality = le16_to_cpup((__le16 *)&data[12]);
274 ctrl->wCompWindowSize = le16_to_cpup((__le16 *)&data[14]);
275 ctrl->wDelay = le16_to_cpup((__le16 *)&data[16]);
276 ctrl->dwMaxVideoFrameSize = get_unaligned_le32(&data[18]);
277 ctrl->dwMaxPayloadTransferSize = get_unaligned_le32(&data[22]);
278
279 if (size >= 34) {
280 ctrl->dwClockFrequency = get_unaligned_le32(&data[26]);
281 ctrl->bmFramingInfo = data[30];
282 ctrl->bPreferedVersion = data[31];
283 ctrl->bMinVersion = data[32];
284 ctrl->bMaxVersion = data[33];
285 } else {
286 ctrl->dwClockFrequency = stream->dev->clock_frequency;
287 ctrl->bmFramingInfo = 0;
288 ctrl->bPreferedVersion = 0;
289 ctrl->bMinVersion = 0;
290 ctrl->bMaxVersion = 0;
291 }
292
293 /* Some broken devices return null or wrong dwMaxVideoFrameSize and
294 * dwMaxPayloadTransferSize fields. Try to get the value from the
295 * format and frame descriptors.
296 */
297 uvc_fixup_video_ctrl(stream, ctrl);
298 ret = 0;
299
300 out:
301 kfree(data);
302 return ret;
303 }
304
uvc_set_video_ctrl(struct uvc_streaming * stream,struct uvc_streaming_control * ctrl,int probe)305 static int uvc_set_video_ctrl(struct uvc_streaming *stream,
306 struct uvc_streaming_control *ctrl, int probe)
307 {
308 u16 size = uvc_video_ctrl_size(stream);
309 u8 *data;
310 int ret;
311
312 data = kzalloc(size, GFP_KERNEL);
313 if (data == NULL)
314 return -ENOMEM;
315
316 *(__le16 *)&data[0] = cpu_to_le16(ctrl->bmHint);
317 data[2] = ctrl->bFormatIndex;
318 data[3] = ctrl->bFrameIndex;
319 *(__le32 *)&data[4] = cpu_to_le32(ctrl->dwFrameInterval);
320 *(__le16 *)&data[8] = cpu_to_le16(ctrl->wKeyFrameRate);
321 *(__le16 *)&data[10] = cpu_to_le16(ctrl->wPFrameRate);
322 *(__le16 *)&data[12] = cpu_to_le16(ctrl->wCompQuality);
323 *(__le16 *)&data[14] = cpu_to_le16(ctrl->wCompWindowSize);
324 *(__le16 *)&data[16] = cpu_to_le16(ctrl->wDelay);
325 put_unaligned_le32(ctrl->dwMaxVideoFrameSize, &data[18]);
326 put_unaligned_le32(ctrl->dwMaxPayloadTransferSize, &data[22]);
327
328 if (size >= 34) {
329 put_unaligned_le32(ctrl->dwClockFrequency, &data[26]);
330 data[30] = ctrl->bmFramingInfo;
331 data[31] = ctrl->bPreferedVersion;
332 data[32] = ctrl->bMinVersion;
333 data[33] = ctrl->bMaxVersion;
334 }
335
336 ret = __uvc_query_ctrl(stream->dev, UVC_SET_CUR, 0, stream->intfnum,
337 probe ? UVC_VS_PROBE_CONTROL : UVC_VS_COMMIT_CONTROL, data,
338 size, uvc_timeout_param);
339 if (ret != size) {
340 dev_err(&stream->intf->dev,
341 "Failed to set UVC %s control : %d (exp. %u).\n",
342 probe ? "probe" : "commit", ret, size);
343 ret = -EIO;
344 }
345
346 kfree(data);
347 return ret;
348 }
349
uvc_probe_video(struct uvc_streaming * stream,struct uvc_streaming_control * probe)350 int uvc_probe_video(struct uvc_streaming *stream,
351 struct uvc_streaming_control *probe)
352 {
353 struct uvc_streaming_control probe_min, probe_max;
354 u16 bandwidth;
355 unsigned int i;
356 int ret;
357
358 /* Perform probing. The device should adjust the requested values
359 * according to its capabilities. However, some devices, namely the
360 * first generation UVC Logitech webcams, don't implement the Video
361 * Probe control properly, and just return the needed bandwidth. For
362 * that reason, if the needed bandwidth exceeds the maximum available
363 * bandwidth, try to lower the quality.
364 */
365 ret = uvc_set_video_ctrl(stream, probe, 1);
366 if (ret < 0)
367 goto done;
368
369 /* Get the minimum and maximum values for compression settings. */
370 if (!(stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX)) {
371 ret = uvc_get_video_ctrl(stream, &probe_min, 1, UVC_GET_MIN);
372 if (ret < 0)
373 goto done;
374 ret = uvc_get_video_ctrl(stream, &probe_max, 1, UVC_GET_MAX);
375 if (ret < 0)
376 goto done;
377
378 probe->wCompQuality = probe_max.wCompQuality;
379 }
380
381 for (i = 0; i < 2; ++i) {
382 ret = uvc_set_video_ctrl(stream, probe, 1);
383 if (ret < 0)
384 goto done;
385 ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
386 if (ret < 0)
387 goto done;
388
389 if (stream->intf->num_altsetting == 1)
390 break;
391
392 bandwidth = probe->dwMaxPayloadTransferSize;
393 if (bandwidth <= stream->maxpsize)
394 break;
395
396 if (stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX) {
397 ret = -ENOSPC;
398 goto done;
399 }
400
401 /* TODO: negotiate compression parameters */
402 probe->wKeyFrameRate = probe_min.wKeyFrameRate;
403 probe->wPFrameRate = probe_min.wPFrameRate;
404 probe->wCompQuality = probe_max.wCompQuality;
405 probe->wCompWindowSize = probe_min.wCompWindowSize;
406 }
407
408 done:
409 return ret;
410 }
411
uvc_commit_video(struct uvc_streaming * stream,struct uvc_streaming_control * probe)412 static int uvc_commit_video(struct uvc_streaming *stream,
413 struct uvc_streaming_control *probe)
414 {
415 return uvc_set_video_ctrl(stream, probe, 0);
416 }
417
418 /* -----------------------------------------------------------------------------
419 * Clocks and timestamps
420 */
421
uvc_video_get_time(void)422 static inline ktime_t uvc_video_get_time(void)
423 {
424 if (uvc_clock_param == CLOCK_MONOTONIC)
425 return ktime_get();
426 else
427 return ktime_get_real();
428 }
429
430 static void
uvc_video_clock_decode(struct uvc_streaming * stream,struct uvc_buffer * buf,const u8 * data,int len)431 uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
432 const u8 *data, int len)
433 {
434 struct uvc_clock_sample *sample;
435 unsigned int header_size;
436 bool has_pts = false;
437 bool has_scr = false;
438 unsigned long flags;
439 ktime_t time;
440 u16 host_sof;
441 u16 dev_sof;
442
443 switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
444 case UVC_STREAM_PTS | UVC_STREAM_SCR:
445 header_size = 12;
446 has_pts = true;
447 has_scr = true;
448 break;
449 case UVC_STREAM_PTS:
450 header_size = 6;
451 has_pts = true;
452 break;
453 case UVC_STREAM_SCR:
454 header_size = 8;
455 has_scr = true;
456 break;
457 default:
458 header_size = 2;
459 break;
460 }
461
462 /* Check for invalid headers. */
463 if (len < header_size)
464 return;
465
466 /* Extract the timestamps:
467 *
468 * - store the frame PTS in the buffer structure
469 * - if the SCR field is present, retrieve the host SOF counter and
470 * kernel timestamps and store them with the SCR STC and SOF fields
471 * in the ring buffer
472 */
473 if (has_pts && buf != NULL)
474 buf->pts = get_unaligned_le32(&data[2]);
475
476 if (!has_scr)
477 return;
478
479 /* To limit the amount of data, drop SCRs with an SOF identical to the
480 * previous one.
481 */
482 dev_sof = get_unaligned_le16(&data[header_size - 2]);
483 if (dev_sof == stream->clock.last_sof)
484 return;
485
486 stream->clock.last_sof = dev_sof;
487
488 host_sof = usb_get_current_frame_number(stream->dev->udev);
489 time = uvc_video_get_time();
490
491 /* The UVC specification allows device implementations that can't obtain
492 * the USB frame number to keep their own frame counters as long as they
493 * match the size and frequency of the frame number associated with USB
494 * SOF tokens. The SOF values sent by such devices differ from the USB
495 * SOF tokens by a fixed offset that needs to be estimated and accounted
496 * for to make timestamp recovery as accurate as possible.
497 *
498 * The offset is estimated the first time a device SOF value is received
499 * as the difference between the host and device SOF values. As the two
500 * SOF values can differ slightly due to transmission delays, consider
501 * that the offset is null if the difference is not higher than 10 ms
502 * (negative differences can not happen and are thus considered as an
503 * offset). The video commit control wDelay field should be used to
504 * compute a dynamic threshold instead of using a fixed 10 ms value, but
505 * devices don't report reliable wDelay values.
506 *
507 * See uvc_video_clock_host_sof() for an explanation regarding why only
508 * the 8 LSBs of the delta are kept.
509 */
510 if (stream->clock.sof_offset == (u16)-1) {
511 u16 delta_sof = (host_sof - dev_sof) & 255;
512 if (delta_sof >= 10)
513 stream->clock.sof_offset = delta_sof;
514 else
515 stream->clock.sof_offset = 0;
516 }
517
518 dev_sof = (dev_sof + stream->clock.sof_offset) & 2047;
519
520 spin_lock_irqsave(&stream->clock.lock, flags);
521
522 sample = &stream->clock.samples[stream->clock.head];
523 sample->dev_stc = get_unaligned_le32(&data[header_size - 6]);
524 sample->dev_sof = dev_sof;
525 sample->host_sof = host_sof;
526 sample->host_time = time;
527
528 /* Update the sliding window head and count. */
529 stream->clock.head = (stream->clock.head + 1) % stream->clock.size;
530
531 if (stream->clock.count < stream->clock.size)
532 stream->clock.count++;
533
534 spin_unlock_irqrestore(&stream->clock.lock, flags);
535 }
536
uvc_video_clock_reset(struct uvc_streaming * stream)537 static void uvc_video_clock_reset(struct uvc_streaming *stream)
538 {
539 struct uvc_clock *clock = &stream->clock;
540
541 clock->head = 0;
542 clock->count = 0;
543 clock->last_sof = -1;
544 clock->sof_offset = -1;
545 }
546
uvc_video_clock_init(struct uvc_streaming * stream)547 static int uvc_video_clock_init(struct uvc_streaming *stream)
548 {
549 struct uvc_clock *clock = &stream->clock;
550
551 spin_lock_init(&clock->lock);
552 clock->size = 32;
553
554 clock->samples = kmalloc_array(clock->size, sizeof(*clock->samples),
555 GFP_KERNEL);
556 if (clock->samples == NULL)
557 return -ENOMEM;
558
559 uvc_video_clock_reset(stream);
560
561 return 0;
562 }
563
uvc_video_clock_cleanup(struct uvc_streaming * stream)564 static void uvc_video_clock_cleanup(struct uvc_streaming *stream)
565 {
566 kfree(stream->clock.samples);
567 stream->clock.samples = NULL;
568 }
569
570 /*
571 * uvc_video_clock_host_sof - Return the host SOF value for a clock sample
572 *
573 * Host SOF counters reported by usb_get_current_frame_number() usually don't
574 * cover the whole 11-bits SOF range (0-2047) but are limited to the HCI frame
575 * schedule window. They can be limited to 8, 9 or 10 bits depending on the host
576 * controller and its configuration.
577 *
578 * We thus need to recover the SOF value corresponding to the host frame number.
579 * As the device and host frame numbers are sampled in a short interval, the
580 * difference between their values should be equal to a small delta plus an
581 * integer multiple of 256 caused by the host frame number limited precision.
582 *
583 * To obtain the recovered host SOF value, compute the small delta by masking
584 * the high bits of the host frame counter and device SOF difference and add it
585 * to the device SOF value.
586 */
uvc_video_clock_host_sof(const struct uvc_clock_sample * sample)587 static u16 uvc_video_clock_host_sof(const struct uvc_clock_sample *sample)
588 {
589 /* The delta value can be negative. */
590 s8 delta_sof;
591
592 delta_sof = (sample->host_sof - sample->dev_sof) & 255;
593
594 return (sample->dev_sof + delta_sof) & 2047;
595 }
596
597 /*
598 * uvc_video_clock_update - Update the buffer timestamp
599 *
600 * This function converts the buffer PTS timestamp to the host clock domain by
601 * going through the USB SOF clock domain and stores the result in the V4L2
602 * buffer timestamp field.
603 *
604 * The relationship between the device clock and the host clock isn't known.
605 * However, the device and the host share the common USB SOF clock which can be
606 * used to recover that relationship.
607 *
608 * The relationship between the device clock and the USB SOF clock is considered
609 * to be linear over the clock samples sliding window and is given by
610 *
611 * SOF = m * PTS + p
612 *
613 * Several methods to compute the slope (m) and intercept (p) can be used. As
614 * the clock drift should be small compared to the sliding window size, we
615 * assume that the line that goes through the points at both ends of the window
616 * is a good approximation. Naming those points P1 and P2, we get
617 *
618 * SOF = (SOF2 - SOF1) / (STC2 - STC1) * PTS
619 * + (SOF1 * STC2 - SOF2 * STC1) / (STC2 - STC1)
620 *
621 * or
622 *
623 * SOF = ((SOF2 - SOF1) * PTS + SOF1 * STC2 - SOF2 * STC1) / (STC2 - STC1) (1)
624 *
625 * to avoid losing precision in the division. Similarly, the host timestamp is
626 * computed with
627 *
628 * TS = ((TS2 - TS1) * SOF + TS1 * SOF2 - TS2 * SOF1) / (SOF2 - SOF1) (2)
629 *
630 * SOF values are coded on 11 bits by USB. We extend their precision with 16
631 * decimal bits, leading to a 11.16 coding.
632 *
633 * TODO: To avoid surprises with device clock values, PTS/STC timestamps should
634 * be normalized using the nominal device clock frequency reported through the
635 * UVC descriptors.
636 *
637 * Both the PTS/STC and SOF counters roll over, after a fixed but device
638 * specific amount of time for PTS/STC and after 2048ms for SOF. As long as the
639 * sliding window size is smaller than the rollover period, differences computed
640 * on unsigned integers will produce the correct result. However, the p term in
641 * the linear relations will be miscomputed.
642 *
643 * To fix the issue, we subtract a constant from the PTS and STC values to bring
644 * PTS to half the 32 bit STC range. The sliding window STC values then fit into
645 * the 32 bit range without any rollover.
646 *
647 * Similarly, we add 2048 to the device SOF values to make sure that the SOF
648 * computed by (1) will never be smaller than 0. This offset is then compensated
649 * by adding 2048 to the SOF values used in (2). However, this doesn't prevent
650 * rollovers between (1) and (2): the SOF value computed by (1) can be slightly
651 * lower than 4096, and the host SOF counters can have rolled over to 2048. This
652 * case is handled by subtracting 2048 from the SOF value if it exceeds the host
653 * SOF value at the end of the sliding window.
654 *
655 * Finally we subtract a constant from the host timestamps to bring the first
656 * timestamp of the sliding window to 1s.
657 */
uvc_video_clock_update(struct uvc_streaming * stream,struct vb2_v4l2_buffer * vbuf,struct uvc_buffer * buf)658 void uvc_video_clock_update(struct uvc_streaming *stream,
659 struct vb2_v4l2_buffer *vbuf,
660 struct uvc_buffer *buf)
661 {
662 struct uvc_clock *clock = &stream->clock;
663 struct uvc_clock_sample *first;
664 struct uvc_clock_sample *last;
665 unsigned long flags;
666 u64 timestamp;
667 u32 delta_stc;
668 u32 y1, y2;
669 u32 x1, x2;
670 u32 mean;
671 u32 sof;
672 u64 y;
673
674 if (!uvc_hw_timestamps_param)
675 return;
676
677 /*
678 * We will get called from __vb2_queue_cancel() if there are buffers
679 * done but not dequeued by the user, but the sample array has already
680 * been released at that time. Just bail out in that case.
681 */
682 if (!clock->samples)
683 return;
684
685 spin_lock_irqsave(&clock->lock, flags);
686
687 if (clock->count < clock->size)
688 goto done;
689
690 first = &clock->samples[clock->head];
691 last = &clock->samples[(clock->head - 1) % clock->size];
692
693 /* First step, PTS to SOF conversion. */
694 delta_stc = buf->pts - (1UL << 31);
695 x1 = first->dev_stc - delta_stc;
696 x2 = last->dev_stc - delta_stc;
697 if (x1 == x2)
698 goto done;
699
700 y1 = (first->dev_sof + 2048) << 16;
701 y2 = (last->dev_sof + 2048) << 16;
702 if (y2 < y1)
703 y2 += 2048 << 16;
704
705 y = (u64)(y2 - y1) * (1ULL << 31) + (u64)y1 * (u64)x2
706 - (u64)y2 * (u64)x1;
707 y = div_u64(y, x2 - x1);
708
709 sof = y;
710
711 uvc_dbg(stream->dev, CLOCK,
712 "%s: PTS %u y %llu.%06llu SOF %u.%06llu (x1 %u x2 %u y1 %u y2 %u SOF offset %u)\n",
713 stream->dev->name, buf->pts,
714 y >> 16, div_u64((y & 0xffff) * 1000000, 65536),
715 sof >> 16, div_u64(((u64)sof & 0xffff) * 1000000LLU, 65536),
716 x1, x2, y1, y2, clock->sof_offset);
717
718 /* Second step, SOF to host clock conversion. */
719 x1 = (uvc_video_clock_host_sof(first) + 2048) << 16;
720 x2 = (uvc_video_clock_host_sof(last) + 2048) << 16;
721 if (x2 < x1)
722 x2 += 2048 << 16;
723 if (x1 == x2)
724 goto done;
725
726 y1 = NSEC_PER_SEC;
727 y2 = (u32)ktime_to_ns(ktime_sub(last->host_time, first->host_time)) + y1;
728
729 /* Interpolated and host SOF timestamps can wrap around at slightly
730 * different times. Handle this by adding or removing 2048 to or from
731 * the computed SOF value to keep it close to the SOF samples mean
732 * value.
733 */
734 mean = (x1 + x2) / 2;
735 if (mean - (1024 << 16) > sof)
736 sof += 2048 << 16;
737 else if (sof > mean + (1024 << 16))
738 sof -= 2048 << 16;
739
740 y = (u64)(y2 - y1) * (u64)sof + (u64)y1 * (u64)x2
741 - (u64)y2 * (u64)x1;
742 y = div_u64(y, x2 - x1);
743
744 timestamp = ktime_to_ns(first->host_time) + y - y1;
745
746 uvc_dbg(stream->dev, CLOCK,
747 "%s: SOF %u.%06llu y %llu ts %llu buf ts %llu (x1 %u/%u/%u x2 %u/%u/%u y1 %u y2 %u)\n",
748 stream->dev->name,
749 sof >> 16, div_u64(((u64)sof & 0xffff) * 1000000LLU, 65536),
750 y, timestamp, vbuf->vb2_buf.timestamp,
751 x1, first->host_sof, first->dev_sof,
752 x2, last->host_sof, last->dev_sof, y1, y2);
753
754 /* Update the V4L2 buffer. */
755 vbuf->vb2_buf.timestamp = timestamp;
756
757 done:
758 spin_unlock_irqrestore(&clock->lock, flags);
759 }
760
761 /* ------------------------------------------------------------------------
762 * Stream statistics
763 */
764
uvc_video_stats_decode(struct uvc_streaming * stream,const u8 * data,int len)765 static void uvc_video_stats_decode(struct uvc_streaming *stream,
766 const u8 *data, int len)
767 {
768 unsigned int header_size;
769 bool has_pts = false;
770 bool has_scr = false;
771 u16 scr_sof;
772 u32 scr_stc;
773 u32 pts;
774
775 if (stream->stats.stream.nb_frames == 0 &&
776 stream->stats.frame.nb_packets == 0)
777 stream->stats.stream.start_ts = ktime_get();
778
779 switch (data[1] & (UVC_STREAM_PTS | UVC_STREAM_SCR)) {
780 case UVC_STREAM_PTS | UVC_STREAM_SCR:
781 header_size = 12;
782 has_pts = true;
783 has_scr = true;
784 break;
785 case UVC_STREAM_PTS:
786 header_size = 6;
787 has_pts = true;
788 break;
789 case UVC_STREAM_SCR:
790 header_size = 8;
791 has_scr = true;
792 break;
793 default:
794 header_size = 2;
795 break;
796 }
797
798 /* Check for invalid headers. */
799 if (len < header_size || data[0] < header_size) {
800 stream->stats.frame.nb_invalid++;
801 return;
802 }
803
804 /* Extract the timestamps. */
805 if (has_pts)
806 pts = get_unaligned_le32(&data[2]);
807
808 if (has_scr) {
809 scr_stc = get_unaligned_le32(&data[header_size - 6]);
810 scr_sof = get_unaligned_le16(&data[header_size - 2]);
811 }
812
813 /* Is PTS constant through the whole frame ? */
814 if (has_pts && stream->stats.frame.nb_pts) {
815 if (stream->stats.frame.pts != pts) {
816 stream->stats.frame.nb_pts_diffs++;
817 stream->stats.frame.last_pts_diff =
818 stream->stats.frame.nb_packets;
819 }
820 }
821
822 if (has_pts) {
823 stream->stats.frame.nb_pts++;
824 stream->stats.frame.pts = pts;
825 }
826
827 /* Do all frames have a PTS in their first non-empty packet, or before
828 * their first empty packet ?
829 */
830 if (stream->stats.frame.size == 0) {
831 if (len > header_size)
832 stream->stats.frame.has_initial_pts = has_pts;
833 if (len == header_size && has_pts)
834 stream->stats.frame.has_early_pts = true;
835 }
836
837 /* Do the SCR.STC and SCR.SOF fields vary through the frame ? */
838 if (has_scr && stream->stats.frame.nb_scr) {
839 if (stream->stats.frame.scr_stc != scr_stc)
840 stream->stats.frame.nb_scr_diffs++;
841 }
842
843 if (has_scr) {
844 /* Expand the SOF counter to 32 bits and store its value. */
845 if (stream->stats.stream.nb_frames > 0 ||
846 stream->stats.frame.nb_scr > 0)
847 stream->stats.stream.scr_sof_count +=
848 (scr_sof - stream->stats.stream.scr_sof) % 2048;
849 stream->stats.stream.scr_sof = scr_sof;
850
851 stream->stats.frame.nb_scr++;
852 stream->stats.frame.scr_stc = scr_stc;
853 stream->stats.frame.scr_sof = scr_sof;
854
855 if (scr_sof < stream->stats.stream.min_sof)
856 stream->stats.stream.min_sof = scr_sof;
857 if (scr_sof > stream->stats.stream.max_sof)
858 stream->stats.stream.max_sof = scr_sof;
859 }
860
861 /* Record the first non-empty packet number. */
862 if (stream->stats.frame.size == 0 && len > header_size)
863 stream->stats.frame.first_data = stream->stats.frame.nb_packets;
864
865 /* Update the frame size. */
866 stream->stats.frame.size += len - header_size;
867
868 /* Update the packets counters. */
869 stream->stats.frame.nb_packets++;
870 if (len <= header_size)
871 stream->stats.frame.nb_empty++;
872
873 if (data[1] & UVC_STREAM_ERR)
874 stream->stats.frame.nb_errors++;
875 }
876
uvc_video_stats_update(struct uvc_streaming * stream)877 static void uvc_video_stats_update(struct uvc_streaming *stream)
878 {
879 struct uvc_stats_frame *frame = &stream->stats.frame;
880
881 uvc_dbg(stream->dev, STATS,
882 "frame %u stats: %u/%u/%u packets, %u/%u/%u pts (%searly %sinitial), %u/%u scr, last pts/stc/sof %u/%u/%u\n",
883 stream->sequence, frame->first_data,
884 frame->nb_packets - frame->nb_empty, frame->nb_packets,
885 frame->nb_pts_diffs, frame->last_pts_diff, frame->nb_pts,
886 frame->has_early_pts ? "" : "!",
887 frame->has_initial_pts ? "" : "!",
888 frame->nb_scr_diffs, frame->nb_scr,
889 frame->pts, frame->scr_stc, frame->scr_sof);
890
891 stream->stats.stream.nb_frames++;
892 stream->stats.stream.nb_packets += stream->stats.frame.nb_packets;
893 stream->stats.stream.nb_empty += stream->stats.frame.nb_empty;
894 stream->stats.stream.nb_errors += stream->stats.frame.nb_errors;
895 stream->stats.stream.nb_invalid += stream->stats.frame.nb_invalid;
896
897 if (frame->has_early_pts)
898 stream->stats.stream.nb_pts_early++;
899 if (frame->has_initial_pts)
900 stream->stats.stream.nb_pts_initial++;
901 if (frame->last_pts_diff <= frame->first_data)
902 stream->stats.stream.nb_pts_constant++;
903 if (frame->nb_scr >= frame->nb_packets - frame->nb_empty)
904 stream->stats.stream.nb_scr_count_ok++;
905 if (frame->nb_scr_diffs + 1 == frame->nb_scr)
906 stream->stats.stream.nb_scr_diffs_ok++;
907
908 memset(&stream->stats.frame, 0, sizeof(stream->stats.frame));
909 }
910
uvc_video_stats_dump(struct uvc_streaming * stream,char * buf,size_t size)911 size_t uvc_video_stats_dump(struct uvc_streaming *stream, char *buf,
912 size_t size)
913 {
914 unsigned int scr_sof_freq;
915 unsigned int duration;
916 size_t count = 0;
917
918 /* Compute the SCR.SOF frequency estimate. At the nominal 1kHz SOF
919 * frequency this will not overflow before more than 1h.
920 */
921 duration = ktime_ms_delta(stream->stats.stream.stop_ts,
922 stream->stats.stream.start_ts);
923 if (duration != 0)
924 scr_sof_freq = stream->stats.stream.scr_sof_count * 1000
925 / duration;
926 else
927 scr_sof_freq = 0;
928
929 count += scnprintf(buf + count, size - count,
930 "frames: %u\npackets: %u\nempty: %u\n"
931 "errors: %u\ninvalid: %u\n",
932 stream->stats.stream.nb_frames,
933 stream->stats.stream.nb_packets,
934 stream->stats.stream.nb_empty,
935 stream->stats.stream.nb_errors,
936 stream->stats.stream.nb_invalid);
937 count += scnprintf(buf + count, size - count,
938 "pts: %u early, %u initial, %u ok\n",
939 stream->stats.stream.nb_pts_early,
940 stream->stats.stream.nb_pts_initial,
941 stream->stats.stream.nb_pts_constant);
942 count += scnprintf(buf + count, size - count,
943 "scr: %u count ok, %u diff ok\n",
944 stream->stats.stream.nb_scr_count_ok,
945 stream->stats.stream.nb_scr_diffs_ok);
946 count += scnprintf(buf + count, size - count,
947 "sof: %u <= sof <= %u, freq %u.%03u kHz\n",
948 stream->stats.stream.min_sof,
949 stream->stats.stream.max_sof,
950 scr_sof_freq / 1000, scr_sof_freq % 1000);
951
952 return count;
953 }
954
uvc_video_stats_start(struct uvc_streaming * stream)955 static void uvc_video_stats_start(struct uvc_streaming *stream)
956 {
957 memset(&stream->stats, 0, sizeof(stream->stats));
958 stream->stats.stream.min_sof = 2048;
959 }
960
uvc_video_stats_stop(struct uvc_streaming * stream)961 static void uvc_video_stats_stop(struct uvc_streaming *stream)
962 {
963 stream->stats.stream.stop_ts = ktime_get();
964 }
965
966 /* ------------------------------------------------------------------------
967 * Video codecs
968 */
969
970 /* Video payload decoding is handled by uvc_video_decode_start(),
971 * uvc_video_decode_data() and uvc_video_decode_end().
972 *
973 * uvc_video_decode_start is called with URB data at the start of a bulk or
974 * isochronous payload. It processes header data and returns the header size
975 * in bytes if successful. If an error occurs, it returns a negative error
976 * code. The following error codes have special meanings.
977 *
978 * - EAGAIN informs the caller that the current video buffer should be marked
979 * as done, and that the function should be called again with the same data
980 * and a new video buffer. This is used when end of frame conditions can be
981 * reliably detected at the beginning of the next frame only.
982 *
983 * If an error other than -EAGAIN is returned, the caller will drop the current
984 * payload. No call to uvc_video_decode_data and uvc_video_decode_end will be
985 * made until the next payload. -ENODATA can be used to drop the current
986 * payload if no other error code is appropriate.
987 *
988 * uvc_video_decode_data is called for every URB with URB data. It copies the
989 * data to the video buffer.
990 *
991 * uvc_video_decode_end is called with header data at the end of a bulk or
992 * isochronous payload. It performs any additional header data processing and
993 * returns 0 or a negative error code if an error occurred. As header data have
994 * already been processed by uvc_video_decode_start, this functions isn't
995 * required to perform sanity checks a second time.
996 *
997 * For isochronous transfers where a payload is always transferred in a single
998 * URB, the three functions will be called in a row.
999 *
1000 * To let the decoder process header data and update its internal state even
1001 * when no video buffer is available, uvc_video_decode_start must be prepared
1002 * to be called with a NULL buf parameter. uvc_video_decode_data and
1003 * uvc_video_decode_end will never be called with a NULL buffer.
1004 */
uvc_video_decode_start(struct uvc_streaming * stream,struct uvc_buffer * buf,const u8 * data,int len)1005 static int uvc_video_decode_start(struct uvc_streaming *stream,
1006 struct uvc_buffer *buf, const u8 *data, int len)
1007 {
1008 u8 fid;
1009
1010 /* Sanity checks:
1011 * - packet must be at least 2 bytes long
1012 * - bHeaderLength value must be at least 2 bytes (see above)
1013 * - bHeaderLength value can't be larger than the packet size.
1014 */
1015 if (len < 2 || data[0] < 2 || data[0] > len) {
1016 stream->stats.frame.nb_invalid++;
1017 return -EINVAL;
1018 }
1019
1020 fid = data[1] & UVC_STREAM_FID;
1021
1022 /* Increase the sequence number regardless of any buffer states, so
1023 * that discontinuous sequence numbers always indicate lost frames.
1024 */
1025 if (stream->last_fid != fid) {
1026 stream->sequence++;
1027 if (stream->sequence)
1028 uvc_video_stats_update(stream);
1029 }
1030
1031 uvc_video_clock_decode(stream, buf, data, len);
1032 uvc_video_stats_decode(stream, data, len);
1033
1034 /* Store the payload FID bit and return immediately when the buffer is
1035 * NULL.
1036 */
1037 if (buf == NULL) {
1038 stream->last_fid = fid;
1039 return -ENODATA;
1040 }
1041
1042 /* Mark the buffer as bad if the error bit is set. */
1043 if (data[1] & UVC_STREAM_ERR) {
1044 uvc_dbg(stream->dev, FRAME,
1045 "Marking buffer as bad (error bit set)\n");
1046 buf->error = 1;
1047 }
1048
1049 /* Synchronize to the input stream by waiting for the FID bit to be
1050 * toggled when the the buffer state is not UVC_BUF_STATE_ACTIVE.
1051 * stream->last_fid is initialized to -1, so the first isochronous
1052 * frame will always be in sync.
1053 *
1054 * If the device doesn't toggle the FID bit, invert stream->last_fid
1055 * when the EOF bit is set to force synchronisation on the next packet.
1056 */
1057 if (buf->state != UVC_BUF_STATE_ACTIVE) {
1058 if (fid == stream->last_fid) {
1059 uvc_dbg(stream->dev, FRAME,
1060 "Dropping payload (out of sync)\n");
1061 if ((stream->dev->quirks & UVC_QUIRK_STREAM_NO_FID) &&
1062 (data[1] & UVC_STREAM_EOF))
1063 stream->last_fid ^= UVC_STREAM_FID;
1064 return -ENODATA;
1065 }
1066
1067 buf->buf.field = V4L2_FIELD_NONE;
1068 buf->buf.sequence = stream->sequence;
1069 buf->buf.vb2_buf.timestamp = ktime_to_ns(uvc_video_get_time());
1070
1071 /* TODO: Handle PTS and SCR. */
1072 buf->state = UVC_BUF_STATE_ACTIVE;
1073 }
1074
1075 /* Mark the buffer as done if we're at the beginning of a new frame.
1076 * End of frame detection is better implemented by checking the EOF
1077 * bit (FID bit toggling is delayed by one frame compared to the EOF
1078 * bit), but some devices don't set the bit at end of frame (and the
1079 * last payload can be lost anyway). We thus must check if the FID has
1080 * been toggled.
1081 *
1082 * stream->last_fid is initialized to -1, so the first isochronous
1083 * frame will never trigger an end of frame detection.
1084 *
1085 * Empty buffers (bytesused == 0) don't trigger end of frame detection
1086 * as it doesn't make sense to return an empty buffer. This also
1087 * avoids detecting end of frame conditions at FID toggling if the
1088 * previous payload had the EOF bit set.
1089 */
1090 if (fid != stream->last_fid && buf->bytesused != 0) {
1091 uvc_dbg(stream->dev, FRAME,
1092 "Frame complete (FID bit toggled)\n");
1093 buf->state = UVC_BUF_STATE_READY;
1094 return -EAGAIN;
1095 }
1096
1097 stream->last_fid = fid;
1098
1099 return data[0];
1100 }
1101
uvc_stream_dir(struct uvc_streaming * stream)1102 static inline enum dma_data_direction uvc_stream_dir(
1103 struct uvc_streaming *stream)
1104 {
1105 if (stream->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
1106 return DMA_FROM_DEVICE;
1107 else
1108 return DMA_TO_DEVICE;
1109 }
1110
uvc_stream_to_dmadev(struct uvc_streaming * stream)1111 static inline struct device *uvc_stream_to_dmadev(struct uvc_streaming *stream)
1112 {
1113 #ifdef __linux__
1114 return bus_to_hcd(stream->dev->udev->bus)->self.sysdev;
1115 #else
1116 return NULL;
1117 #endif
1118 }
1119
uvc_submit_urb(struct uvc_urb * uvc_urb,gfp_t mem_flags)1120 static int uvc_submit_urb(struct uvc_urb *uvc_urb, gfp_t mem_flags)
1121 {
1122 /* Sync DMA. */
1123 dma_sync_sgtable_for_device(uvc_stream_to_dmadev(uvc_urb->stream),
1124 uvc_urb->sgt,
1125 uvc_stream_dir(uvc_urb->stream));
1126 return usb_submit_urb(uvc_urb->urb, mem_flags);
1127 }
1128
1129 /*
1130 * uvc_video_decode_data_work: Asynchronous memcpy processing
1131 *
1132 * Copy URB data to video buffers in process context, releasing buffer
1133 * references and requeuing the URB when done.
1134 */
uvc_video_copy_data_work(struct work_struct * work)1135 static void uvc_video_copy_data_work(struct work_struct *work)
1136 {
1137 struct uvc_urb *uvc_urb = container_of(work, struct uvc_urb, work);
1138 unsigned int i;
1139 int ret;
1140
1141 for (i = 0; i < uvc_urb->async_operations; i++) {
1142 struct uvc_copy_op *op = &uvc_urb->copy_operations[i];
1143
1144 memcpy(op->dst, op->src, op->len);
1145
1146 /* Release reference taken on this buffer. */
1147 uvc_queue_buffer_release(op->buf);
1148 }
1149
1150 ret = uvc_submit_urb(uvc_urb, GFP_KERNEL);
1151 if (ret < 0)
1152 dev_err(&uvc_urb->stream->intf->dev,
1153 "Failed to resubmit video URB (%d).\n", ret);
1154 }
1155
uvc_video_decode_data(struct uvc_urb * uvc_urb,struct uvc_buffer * buf,const u8 * data,int len)1156 static void uvc_video_decode_data(struct uvc_urb *uvc_urb,
1157 struct uvc_buffer *buf, const u8 *data, int len)
1158 {
1159 unsigned int active_op = uvc_urb->async_operations;
1160 struct uvc_copy_op *op = &uvc_urb->copy_operations[active_op];
1161 unsigned int maxlen;
1162
1163 if (len <= 0)
1164 return;
1165
1166 maxlen = buf->length - buf->bytesused;
1167
1168 /* Take a buffer reference for async work. */
1169 kref_get(&buf->ref);
1170
1171 op->buf = buf;
1172 op->src = data;
1173 op->dst = buf->mem + buf->bytesused;
1174 op->len = min_t(unsigned int, len, maxlen);
1175
1176 buf->bytesused += op->len;
1177
1178 /* Complete the current frame if the buffer size was exceeded. */
1179 if (len > maxlen) {
1180 uvc_dbg(uvc_urb->stream->dev, FRAME,
1181 "Frame complete (overflow)\n");
1182 buf->error = 1;
1183 buf->state = UVC_BUF_STATE_READY;
1184 }
1185
1186 uvc_urb->async_operations++;
1187 }
1188
uvc_video_decode_end(struct uvc_streaming * stream,struct uvc_buffer * buf,const u8 * data,int len)1189 static void uvc_video_decode_end(struct uvc_streaming *stream,
1190 struct uvc_buffer *buf, const u8 *data, int len)
1191 {
1192 /* Mark the buffer as done if the EOF marker is set. */
1193 if (data[1] & UVC_STREAM_EOF && buf->bytesused != 0) {
1194 uvc_dbg(stream->dev, FRAME, "Frame complete (EOF found)\n");
1195 if (data[0] == len)
1196 uvc_dbg(stream->dev, FRAME, "EOF in empty payload\n");
1197 buf->state = UVC_BUF_STATE_READY;
1198 if (stream->dev->quirks & UVC_QUIRK_STREAM_NO_FID)
1199 stream->last_fid ^= UVC_STREAM_FID;
1200 }
1201 }
1202
1203 /* Video payload encoding is handled by uvc_video_encode_header() and
1204 * uvc_video_encode_data(). Only bulk transfers are currently supported.
1205 *
1206 * uvc_video_encode_header is called at the start of a payload. It adds header
1207 * data to the transfer buffer and returns the header size. As the only known
1208 * UVC output device transfers a whole frame in a single payload, the EOF bit
1209 * is always set in the header.
1210 *
1211 * uvc_video_encode_data is called for every URB and copies the data from the
1212 * video buffer to the transfer buffer.
1213 */
uvc_video_encode_header(struct uvc_streaming * stream,struct uvc_buffer * buf,u8 * data,int len)1214 static int uvc_video_encode_header(struct uvc_streaming *stream,
1215 struct uvc_buffer *buf, u8 *data, int len)
1216 {
1217 data[0] = 2; /* Header length */
1218 data[1] = UVC_STREAM_EOH | UVC_STREAM_EOF
1219 | (stream->last_fid & UVC_STREAM_FID);
1220 return 2;
1221 }
1222
uvc_video_encode_data(struct uvc_streaming * stream,struct uvc_buffer * buf,u8 * data,int len)1223 static int uvc_video_encode_data(struct uvc_streaming *stream,
1224 struct uvc_buffer *buf, u8 *data, int len)
1225 {
1226 struct uvc_video_queue *queue = &stream->queue;
1227 unsigned int nbytes;
1228 void *mem;
1229
1230 /* Copy video data to the URB buffer. */
1231 mem = buf->mem + queue->buf_used;
1232 nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);
1233 nbytes = min(stream->bulk.max_payload_size - stream->bulk.payload_size,
1234 nbytes);
1235 memcpy(data, mem, nbytes);
1236
1237 queue->buf_used += nbytes;
1238
1239 return nbytes;
1240 }
1241
1242 /* ------------------------------------------------------------------------
1243 * Metadata
1244 */
1245
1246 /*
1247 * Additionally to the payload headers we also want to provide the user with USB
1248 * Frame Numbers and system time values. The resulting buffer is thus composed
1249 * of blocks, containing a 64-bit timestamp in nanoseconds, a 16-bit USB Frame
1250 * Number, and a copy of the payload header.
1251 *
1252 * Ideally we want to capture all payload headers for each frame. However, their
1253 * number is unknown and unbound. We thus drop headers that contain no vendor
1254 * data and that either contain no SCR value or an SCR value identical to the
1255 * previous header.
1256 */
uvc_video_decode_meta(struct uvc_streaming * stream,struct uvc_buffer * meta_buf,const u8 * mem,unsigned int length)1257 static void uvc_video_decode_meta(struct uvc_streaming *stream,
1258 struct uvc_buffer *meta_buf,
1259 const u8 *mem, unsigned int length)
1260 {
1261 struct uvc_meta_buf *meta;
1262 size_t len_std = 2;
1263 bool has_pts, has_scr;
1264 unsigned long flags;
1265 unsigned int sof;
1266 ktime_t time;
1267 const u8 *scr;
1268
1269 if (!meta_buf || length == 2)
1270 return;
1271
1272 if (meta_buf->length - meta_buf->bytesused <
1273 length + sizeof(meta->ns) + sizeof(meta->sof)) {
1274 meta_buf->error = 1;
1275 return;
1276 }
1277
1278 has_pts = mem[1] & UVC_STREAM_PTS;
1279 has_scr = mem[1] & UVC_STREAM_SCR;
1280
1281 if (has_pts) {
1282 len_std += 4;
1283 scr = mem + 6;
1284 } else {
1285 scr = mem + 2;
1286 }
1287
1288 if (has_scr)
1289 len_std += 6;
1290
1291 if (stream->meta.format == V4L2_META_FMT_UVC)
1292 length = len_std;
1293
1294 if (length == len_std && (!has_scr ||
1295 !memcmp(scr, stream->clock.last_scr, 6)))
1296 return;
1297
1298 meta = (struct uvc_meta_buf *)((u8 *)meta_buf->mem + meta_buf->bytesused);
1299 local_irq_save(flags);
1300 time = uvc_video_get_time();
1301 sof = usb_get_current_frame_number(stream->dev->udev);
1302 local_irq_restore(flags);
1303 put_unaligned(ktime_to_ns(time), &meta->ns);
1304 put_unaligned(sof, &meta->sof);
1305
1306 if (has_scr)
1307 memcpy(stream->clock.last_scr, scr, 6);
1308
1309 memcpy(&meta->length, mem, length);
1310 meta_buf->bytesused += length + sizeof(meta->ns) + sizeof(meta->sof);
1311
1312 uvc_dbg(stream->dev, FRAME,
1313 "%s(): t-sys %lluns, SOF %u, len %u, flags 0x%x, PTS %u, STC %u frame SOF %u\n",
1314 __func__, ktime_to_ns(time), meta->sof, meta->length,
1315 meta->flags,
1316 has_pts ? *(u32 *)meta->buf : 0,
1317 has_scr ? *(u32 *)scr : 0,
1318 has_scr ? *(u32 *)(scr + 4) & 0x7ff : 0);
1319 }
1320
1321 /* ------------------------------------------------------------------------
1322 * URB handling
1323 */
1324
1325 /*
1326 * Set error flag for incomplete buffer.
1327 */
uvc_video_validate_buffer(const struct uvc_streaming * stream,struct uvc_buffer * buf)1328 static void uvc_video_validate_buffer(const struct uvc_streaming *stream,
1329 struct uvc_buffer *buf)
1330 {
1331 if (stream->ctrl.dwMaxVideoFrameSize != buf->bytesused &&
1332 !(stream->cur_format->flags & UVC_FMT_FLAG_COMPRESSED))
1333 buf->error = 1;
1334 }
1335
1336 /*
1337 * Completion handler for video URBs.
1338 */
1339
uvc_video_next_buffers(struct uvc_streaming * stream,struct uvc_buffer ** video_buf,struct uvc_buffer ** meta_buf)1340 static void uvc_video_next_buffers(struct uvc_streaming *stream,
1341 struct uvc_buffer **video_buf, struct uvc_buffer **meta_buf)
1342 {
1343 uvc_video_validate_buffer(stream, *video_buf);
1344
1345 if (*meta_buf) {
1346 struct vb2_v4l2_buffer *vb2_meta = &(*meta_buf)->buf;
1347 const struct vb2_v4l2_buffer *vb2_video = &(*video_buf)->buf;
1348
1349 vb2_meta->sequence = vb2_video->sequence;
1350 vb2_meta->field = vb2_video->field;
1351 vb2_meta->vb2_buf.timestamp = vb2_video->vb2_buf.timestamp;
1352
1353 (*meta_buf)->state = UVC_BUF_STATE_READY;
1354 if (!(*meta_buf)->error)
1355 (*meta_buf)->error = (*video_buf)->error;
1356 *meta_buf = uvc_queue_next_buffer(&stream->meta.queue,
1357 *meta_buf);
1358 }
1359 *video_buf = uvc_queue_next_buffer(&stream->queue, *video_buf);
1360 }
1361
uvc_video_decode_isoc(struct uvc_urb * uvc_urb,struct uvc_buffer * buf,struct uvc_buffer * meta_buf)1362 static void uvc_video_decode_isoc(struct uvc_urb *uvc_urb,
1363 struct uvc_buffer *buf, struct uvc_buffer *meta_buf)
1364 {
1365 struct urb *urb = uvc_urb->urb;
1366 struct uvc_streaming *stream = uvc_urb->stream;
1367 u8 *mem;
1368 int ret, i;
1369
1370 for (i = 0; i < urb->number_of_packets; ++i) {
1371 if (urb->iso_frame_desc[i].status < 0) {
1372 uvc_dbg(stream->dev, FRAME,
1373 "USB isochronous frame lost (%d)\n",
1374 urb->iso_frame_desc[i].status);
1375 /* Mark the buffer as faulty. */
1376 if (buf != NULL)
1377 buf->error = 1;
1378 continue;
1379 }
1380
1381 /* Decode the payload header. */
1382 mem = urb->transfer_buffer + urb->iso_frame_desc[i].offset;
1383 do {
1384 ret = uvc_video_decode_start(stream, buf, mem,
1385 urb->iso_frame_desc[i].actual_length);
1386 if (ret == -EAGAIN)
1387 uvc_video_next_buffers(stream, &buf, &meta_buf);
1388 } while (ret == -EAGAIN);
1389
1390 if (ret < 0)
1391 continue;
1392
1393 uvc_video_decode_meta(stream, meta_buf, mem, ret);
1394
1395 /* Decode the payload data. */
1396 uvc_video_decode_data(uvc_urb, buf, mem + ret,
1397 urb->iso_frame_desc[i].actual_length - ret);
1398
1399 /* Process the header again. */
1400 uvc_video_decode_end(stream, buf, mem,
1401 urb->iso_frame_desc[i].actual_length);
1402
1403 if (buf->state == UVC_BUF_STATE_READY)
1404 uvc_video_next_buffers(stream, &buf, &meta_buf);
1405 }
1406 }
1407
uvc_video_decode_bulk(struct uvc_urb * uvc_urb,struct uvc_buffer * buf,struct uvc_buffer * meta_buf)1408 static void uvc_video_decode_bulk(struct uvc_urb *uvc_urb,
1409 struct uvc_buffer *buf, struct uvc_buffer *meta_buf)
1410 {
1411 struct urb *urb = uvc_urb->urb;
1412 struct uvc_streaming *stream = uvc_urb->stream;
1413 u8 *mem;
1414 int len, ret;
1415
1416 /*
1417 * Ignore ZLPs if they're not part of a frame, otherwise process them
1418 * to trigger the end of payload detection.
1419 */
1420 if (urb->actual_length == 0 && stream->bulk.header_size == 0)
1421 return;
1422
1423 mem = urb->transfer_buffer;
1424 len = urb->actual_length;
1425 stream->bulk.payload_size += len;
1426
1427 /* If the URB is the first of its payload, decode and save the
1428 * header.
1429 */
1430 if (stream->bulk.header_size == 0 && !stream->bulk.skip_payload) {
1431 do {
1432 ret = uvc_video_decode_start(stream, buf, mem, len);
1433 if (ret == -EAGAIN)
1434 uvc_video_next_buffers(stream, &buf, &meta_buf);
1435 } while (ret == -EAGAIN);
1436
1437 /* If an error occurred skip the rest of the payload. */
1438 if (ret < 0 || buf == NULL) {
1439 stream->bulk.skip_payload = 1;
1440 } else {
1441 memcpy(stream->bulk.header, mem, ret);
1442 stream->bulk.header_size = ret;
1443
1444 uvc_video_decode_meta(stream, meta_buf, mem, ret);
1445
1446 mem += ret;
1447 len -= ret;
1448 }
1449 }
1450
1451 /* The buffer queue might have been cancelled while a bulk transfer
1452 * was in progress, so we can reach here with buf equal to NULL. Make
1453 * sure buf is never dereferenced if NULL.
1454 */
1455
1456 /* Prepare video data for processing. */
1457 if (!stream->bulk.skip_payload && buf != NULL)
1458 uvc_video_decode_data(uvc_urb, buf, mem, len);
1459
1460 /* Detect the payload end by a URB smaller than the maximum size (or
1461 * a payload size equal to the maximum) and process the header again.
1462 */
1463 if (urb->actual_length < urb->transfer_buffer_length ||
1464 stream->bulk.payload_size >= stream->bulk.max_payload_size) {
1465 if (!stream->bulk.skip_payload && buf != NULL) {
1466 uvc_video_decode_end(stream, buf, stream->bulk.header,
1467 stream->bulk.payload_size);
1468 if (buf->state == UVC_BUF_STATE_READY)
1469 uvc_video_next_buffers(stream, &buf, &meta_buf);
1470 }
1471
1472 stream->bulk.header_size = 0;
1473 stream->bulk.skip_payload = 0;
1474 stream->bulk.payload_size = 0;
1475 }
1476 }
1477
uvc_video_encode_bulk(struct uvc_urb * uvc_urb,struct uvc_buffer * buf,struct uvc_buffer * meta_buf)1478 static void uvc_video_encode_bulk(struct uvc_urb *uvc_urb,
1479 struct uvc_buffer *buf, struct uvc_buffer *meta_buf)
1480 {
1481 struct urb *urb = uvc_urb->urb;
1482 struct uvc_streaming *stream = uvc_urb->stream;
1483
1484 u8 *mem = urb->transfer_buffer;
1485 int len = stream->urb_size, ret;
1486
1487 if (buf == NULL) {
1488 urb->transfer_buffer_length = 0;
1489 return;
1490 }
1491
1492 /* If the URB is the first of its payload, add the header. */
1493 if (stream->bulk.header_size == 0) {
1494 ret = uvc_video_encode_header(stream, buf, mem, len);
1495 stream->bulk.header_size = ret;
1496 stream->bulk.payload_size += ret;
1497 mem += ret;
1498 len -= ret;
1499 }
1500
1501 /* Process video data. */
1502 ret = uvc_video_encode_data(stream, buf, mem, len);
1503
1504 stream->bulk.payload_size += ret;
1505 len -= ret;
1506
1507 if (buf->bytesused == stream->queue.buf_used ||
1508 stream->bulk.payload_size == stream->bulk.max_payload_size) {
1509 if (buf->bytesused == stream->queue.buf_used) {
1510 stream->queue.buf_used = 0;
1511 buf->state = UVC_BUF_STATE_READY;
1512 buf->buf.sequence = ++stream->sequence;
1513 uvc_queue_next_buffer(&stream->queue, buf);
1514 stream->last_fid ^= UVC_STREAM_FID;
1515 }
1516
1517 stream->bulk.header_size = 0;
1518 stream->bulk.payload_size = 0;
1519 }
1520
1521 urb->transfer_buffer_length = stream->urb_size - len;
1522 }
1523
uvc_video_complete(struct urb * urb)1524 static void uvc_video_complete(struct urb *urb)
1525 {
1526 struct uvc_urb *uvc_urb = urb->context;
1527 struct uvc_streaming *stream = uvc_urb->stream;
1528 struct uvc_video_queue *queue = &stream->queue;
1529 struct uvc_video_queue *qmeta = &stream->meta.queue;
1530 struct vb2_queue *vb2_qmeta = stream->meta.vdev.queue;
1531 struct uvc_buffer *buf = NULL;
1532 struct uvc_buffer *buf_meta = NULL;
1533 unsigned long flags;
1534 int ret;
1535
1536 switch (urb->status) {
1537 case 0:
1538 break;
1539
1540 default:
1541 dev_warn(&stream->intf->dev,
1542 "Non-zero status (%d) in video completion handler.\n",
1543 urb->status);
1544 fallthrough;
1545 case -ENOENT: /* usb_poison_urb() called. */
1546 if (stream->frozen)
1547 return;
1548 fallthrough;
1549 case -ECONNRESET: /* usb_unlink_urb() called. */
1550 case -ESHUTDOWN: /* The endpoint is being disabled. */
1551 uvc_queue_cancel(queue, urb->status == -ESHUTDOWN);
1552 if (vb2_qmeta)
1553 uvc_queue_cancel(qmeta, urb->status == -ESHUTDOWN);
1554 return;
1555 }
1556
1557 buf = uvc_queue_get_current_buffer(queue);
1558
1559 if (vb2_qmeta) {
1560 spin_lock_irqsave(&qmeta->irqlock, flags);
1561 if (!list_empty(&qmeta->irqqueue))
1562 buf_meta = list_first_entry(&qmeta->irqqueue,
1563 struct uvc_buffer, queue);
1564 spin_unlock_irqrestore(&qmeta->irqlock, flags);
1565 }
1566
1567 /* Re-initialise the URB async work. */
1568 uvc_urb->async_operations = 0;
1569
1570 /* Sync DMA and invalidate vmap range. */
1571 dma_sync_sgtable_for_cpu(uvc_stream_to_dmadev(uvc_urb->stream),
1572 uvc_urb->sgt, uvc_stream_dir(stream));
1573 invalidate_kernel_vmap_range(uvc_urb->buffer,
1574 uvc_urb->stream->urb_size);
1575
1576 /*
1577 * Process the URB headers, and optionally queue expensive memcpy tasks
1578 * to be deferred to a work queue.
1579 */
1580 stream->decode(uvc_urb, buf, buf_meta);
1581
1582 /* If no async work is needed, resubmit the URB immediately. */
1583 if (!uvc_urb->async_operations) {
1584 ret = uvc_submit_urb(uvc_urb, GFP_ATOMIC);
1585 if (ret < 0)
1586 dev_err(&stream->intf->dev,
1587 "Failed to resubmit video URB (%d).\n", ret);
1588 return;
1589 }
1590
1591 queue_work(stream->async_wq, &uvc_urb->work);
1592 }
1593
1594 /*
1595 * Free transfer buffers.
1596 */
uvc_free_urb_buffers(struct uvc_streaming * stream)1597 static void uvc_free_urb_buffers(struct uvc_streaming *stream)
1598 {
1599 struct device *dma_dev = uvc_stream_to_dmadev(stream);
1600 struct uvc_urb *uvc_urb;
1601
1602 for_each_uvc_urb(uvc_urb, stream) {
1603 if (!uvc_urb->buffer)
1604 continue;
1605
1606 dma_vunmap_noncontiguous(dma_dev, uvc_urb->buffer);
1607 dma_free_noncontiguous(dma_dev, stream->urb_size, uvc_urb->sgt,
1608 uvc_stream_dir(stream));
1609
1610 uvc_urb->buffer = NULL;
1611 uvc_urb->sgt = NULL;
1612 }
1613
1614 stream->urb_size = 0;
1615 }
1616
uvc_alloc_urb_buffer(struct uvc_streaming * stream,struct uvc_urb * uvc_urb,gfp_t gfp_flags)1617 static bool uvc_alloc_urb_buffer(struct uvc_streaming *stream,
1618 struct uvc_urb *uvc_urb, gfp_t gfp_flags)
1619 {
1620 struct device *dma_dev = uvc_stream_to_dmadev(stream);
1621
1622 uvc_urb->sgt = dma_alloc_noncontiguous(dma_dev, stream->urb_size,
1623 uvc_stream_dir(stream),
1624 gfp_flags, 0);
1625 if (!uvc_urb->sgt)
1626 return false;
1627 uvc_urb->dma = uvc_urb->sgt->sgl->dma_address;
1628
1629 uvc_urb->buffer = dma_vmap_noncontiguous(dma_dev, stream->urb_size,
1630 uvc_urb->sgt);
1631 if (!uvc_urb->buffer) {
1632 dma_free_noncontiguous(dma_dev, stream->urb_size,
1633 uvc_urb->sgt,
1634 uvc_stream_dir(stream));
1635 uvc_urb->sgt = NULL;
1636 return false;
1637 }
1638
1639 return true;
1640 }
1641
1642 /*
1643 * Allocate transfer buffers. This function can be called with buffers
1644 * already allocated when resuming from suspend, in which case it will
1645 * return without touching the buffers.
1646 *
1647 * Limit the buffer size to UVC_MAX_PACKETS bulk/isochronous packets. If the
1648 * system is too low on memory try successively smaller numbers of packets
1649 * until allocation succeeds.
1650 *
1651 * Return the number of allocated packets on success or 0 when out of memory.
1652 */
uvc_alloc_urb_buffers(struct uvc_streaming * stream,unsigned int size,unsigned int psize,gfp_t gfp_flags)1653 static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
1654 unsigned int size, unsigned int psize, gfp_t gfp_flags)
1655 {
1656 unsigned int npackets;
1657 unsigned int i;
1658
1659 /* Buffers are already allocated, bail out. */
1660 if (stream->urb_size)
1661 return stream->urb_size / psize;
1662
1663 /* Compute the number of packets. Bulk endpoints might transfer UVC
1664 * payloads across multiple URBs.
1665 */
1666 npackets = size / psize;
1667
1668 /* Retry allocations until one succeed. */
1669 for (; npackets > 1; npackets /= 2) {
1670 stream->urb_size = psize * npackets;
1671
1672 for (i = 0; i < UVC_URBS; ++i) {
1673 struct uvc_urb *uvc_urb = &stream->uvc_urb[i];
1674
1675 if (!uvc_alloc_urb_buffer(stream, uvc_urb, gfp_flags)) {
1676 uvc_free_urb_buffers(stream);
1677 break;
1678 }
1679
1680 uvc_urb->stream = stream;
1681 }
1682
1683 if (i == UVC_URBS) {
1684 uvc_dbg(stream->dev, VIDEO,
1685 "Allocated %u URB buffers of %ux%u bytes each\n",
1686 UVC_URBS, npackets, psize);
1687 return npackets;
1688 }
1689 }
1690
1691 uvc_dbg(stream->dev, VIDEO,
1692 "Failed to allocate URB buffers (%u bytes per packet)\n",
1693 psize);
1694 return 0;
1695 }
1696
1697 /*
1698 * Uninitialize isochronous/bulk URBs and free transfer buffers.
1699 */
uvc_video_stop_transfer(struct uvc_streaming * stream,int free_buffers)1700 static void uvc_video_stop_transfer(struct uvc_streaming *stream,
1701 int free_buffers)
1702 {
1703 struct uvc_urb *uvc_urb;
1704
1705 uvc_video_stats_stop(stream);
1706
1707 /*
1708 * We must poison the URBs rather than kill them to ensure that even
1709 * after the completion handler returns, any asynchronous workqueues
1710 * will be prevented from resubmitting the URBs.
1711 */
1712 for_each_uvc_urb(uvc_urb, stream)
1713 usb_poison_urb(uvc_urb->urb);
1714
1715 flush_workqueue(stream->async_wq);
1716
1717 for_each_uvc_urb(uvc_urb, stream) {
1718 usb_free_urb(uvc_urb->urb);
1719 uvc_urb->urb = NULL;
1720 }
1721
1722 if (free_buffers)
1723 uvc_free_urb_buffers(stream);
1724 }
1725
1726 /*
1727 * Compute the maximum number of bytes per interval for an endpoint.
1728 */
uvc_endpoint_max_bpi(struct usb_device * dev,struct usb_host_endpoint * ep)1729 static unsigned int uvc_endpoint_max_bpi(struct usb_device *dev,
1730 struct usb_host_endpoint *ep)
1731 {
1732 u16 psize;
1733 u16 mult;
1734
1735 switch (dev->speed) {
1736 case USB_SPEED_SUPER:
1737 case USB_SPEED_SUPER_PLUS:
1738 return le16_to_cpu(ep->ss_ep_comp.wBytesPerInterval);
1739 case USB_SPEED_HIGH:
1740 psize = usb_endpoint_maxp(&ep->desc);
1741 mult = usb_endpoint_maxp_mult(&ep->desc);
1742 return psize * mult;
1743 case USB_SPEED_WIRELESS:
1744 psize = usb_endpoint_maxp(&ep->desc);
1745 return psize;
1746 default:
1747 psize = usb_endpoint_maxp(&ep->desc);
1748 return psize;
1749 }
1750 }
1751
1752 /*
1753 * Initialize isochronous URBs and allocate transfer buffers. The packet size
1754 * is given by the endpoint.
1755 */
uvc_init_video_isoc(struct uvc_streaming * stream,struct usb_host_endpoint * ep,gfp_t gfp_flags)1756 static int uvc_init_video_isoc(struct uvc_streaming *stream,
1757 struct usb_host_endpoint *ep, gfp_t gfp_flags)
1758 {
1759 struct urb *urb;
1760 struct uvc_urb *uvc_urb;
1761 unsigned int npackets, i;
1762 u16 psize;
1763 u32 size;
1764
1765 psize = uvc_endpoint_max_bpi(stream->dev->udev, ep);
1766
1767 if (stream->dev->udev->speed == USB_SPEED_FULL) {
1768 /* (8000 >> 3) = 1000 FPS */
1769 size = (UVC_MAX_PACKETS >> 3) * psize;
1770 } else {
1771 /* 1000 - 8000 FPS, figure out */
1772 size = ep->desc.bInterval;
1773 if (size > 0)
1774 size --;
1775 if (size > 3)
1776 size = 3;
1777 size = (UVC_MAX_PACKETS >> size) * psize;
1778 }
1779
1780 /* avoid division by zero */
1781 if (psize == 0)
1782 return -EINVAL;
1783
1784 npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
1785 if (npackets == 0)
1786 return -ENOMEM;
1787
1788 size = npackets * psize;
1789
1790 for_each_uvc_urb(uvc_urb, stream) {
1791 urb = usb_alloc_urb(npackets, gfp_flags);
1792 if (urb == NULL) {
1793 uvc_video_stop_transfer(stream, 1);
1794 return -ENOMEM;
1795 }
1796
1797 urb->dev = stream->dev->udev;
1798 urb->context = uvc_urb;
1799 urb->pipe = usb_rcvisocpipe(stream->dev->udev,
1800 ep->desc.bEndpointAddress);
1801 urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
1802 urb->transfer_dma = uvc_urb->dma;
1803 urb->interval = ep->desc.bInterval;
1804 urb->transfer_buffer = uvc_urb->buffer;
1805 urb->complete = uvc_video_complete;
1806 urb->number_of_packets = npackets;
1807 urb->transfer_buffer_length = size;
1808
1809 for (i = 0; i < npackets; ++i) {
1810 urb->iso_frame_desc[i].offset = i * psize;
1811 urb->iso_frame_desc[i].length = psize;
1812 }
1813
1814 uvc_urb->urb = urb;
1815 }
1816
1817 return 0;
1818 }
1819
1820 /*
1821 * Initialize bulk URBs and allocate transfer buffers. The packet size is
1822 * given by the endpoint.
1823 */
uvc_init_video_bulk(struct uvc_streaming * stream,struct usb_host_endpoint * ep,gfp_t gfp_flags)1824 static int uvc_init_video_bulk(struct uvc_streaming *stream,
1825 struct usb_host_endpoint *ep, gfp_t gfp_flags)
1826 {
1827 struct urb *urb;
1828 struct uvc_urb *uvc_urb;
1829 unsigned int npackets, pipe;
1830 u16 psize;
1831 u32 size;
1832
1833 psize = usb_endpoint_maxp(&ep->desc);
1834 size = stream->ctrl.dwMaxPayloadTransferSize;
1835 stream->bulk.max_payload_size = size;
1836
1837 npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
1838 if (npackets == 0)
1839 return -ENOMEM;
1840
1841 size = npackets * psize;
1842
1843 if (usb_endpoint_dir_in(&ep->desc))
1844 pipe = usb_rcvbulkpipe(stream->dev->udev,
1845 ep->desc.bEndpointAddress);
1846 else
1847 pipe = usb_sndbulkpipe(stream->dev->udev,
1848 ep->desc.bEndpointAddress);
1849
1850 if (stream->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
1851 size = 0;
1852
1853 for_each_uvc_urb(uvc_urb, stream) {
1854 urb = usb_alloc_urb(0, gfp_flags);
1855 if (urb == NULL) {
1856 uvc_video_stop_transfer(stream, 1);
1857 return -ENOMEM;
1858 }
1859
1860 usb_fill_bulk_urb(urb, stream->dev->udev, pipe, uvc_urb->buffer,
1861 size, uvc_video_complete, uvc_urb);
1862 urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1863 urb->transfer_dma = uvc_urb->dma;
1864
1865 uvc_urb->urb = urb;
1866 }
1867
1868 return 0;
1869 }
1870
1871 /*
1872 * Initialize isochronous/bulk URBs and allocate transfer buffers.
1873 */
uvc_video_start_transfer(struct uvc_streaming * stream,gfp_t gfp_flags)1874 static int uvc_video_start_transfer(struct uvc_streaming *stream,
1875 gfp_t gfp_flags)
1876 {
1877 struct usb_interface *intf = stream->intf;
1878 struct usb_host_endpoint *ep;
1879 struct uvc_urb *uvc_urb;
1880 unsigned int i;
1881 int ret;
1882
1883 stream->sequence = -1;
1884 stream->last_fid = -1;
1885 stream->bulk.header_size = 0;
1886 stream->bulk.skip_payload = 0;
1887 stream->bulk.payload_size = 0;
1888
1889 uvc_video_stats_start(stream);
1890
1891 if (intf->num_altsetting > 1) {
1892 struct usb_host_endpoint *best_ep = NULL;
1893 unsigned int best_psize = UINT_MAX;
1894 unsigned int bandwidth;
1895 unsigned int altsetting;
1896 int intfnum = stream->intfnum;
1897
1898 /* Isochronous endpoint, select the alternate setting. */
1899 bandwidth = stream->ctrl.dwMaxPayloadTransferSize;
1900
1901 if (bandwidth == 0) {
1902 uvc_dbg(stream->dev, VIDEO,
1903 "Device requested null bandwidth, defaulting to lowest\n");
1904 bandwidth = 1;
1905 } else {
1906 uvc_dbg(stream->dev, VIDEO,
1907 "Device requested %u B/frame bandwidth\n",
1908 bandwidth);
1909 }
1910
1911 for (i = 0; i < intf->num_altsetting; ++i) {
1912 struct usb_host_interface *alts;
1913 unsigned int psize;
1914
1915 alts = &intf->altsetting[i];
1916 ep = uvc_find_endpoint(alts,
1917 stream->header.bEndpointAddress);
1918 if (ep == NULL)
1919 continue;
1920
1921 /* Check if the bandwidth is high enough. */
1922 psize = uvc_endpoint_max_bpi(stream->dev->udev, ep);
1923 if (psize >= bandwidth && psize <= best_psize) {
1924 altsetting = alts->desc.bAlternateSetting;
1925 best_psize = psize;
1926 best_ep = ep;
1927 }
1928 }
1929
1930 if (best_ep == NULL) {
1931 uvc_dbg(stream->dev, VIDEO,
1932 "No fast enough alt setting for requested bandwidth\n");
1933 return -EIO;
1934 }
1935
1936 uvc_dbg(stream->dev, VIDEO,
1937 "Selecting alternate setting %u (%u B/frame bandwidth)\n",
1938 altsetting, best_psize);
1939
1940 ret = usb_set_interface(stream->dev->udev, intfnum, altsetting);
1941 if (ret < 0)
1942 return ret;
1943
1944 ret = uvc_init_video_isoc(stream, best_ep, gfp_flags);
1945 } else {
1946 /* Bulk endpoint, proceed to URB initialization. */
1947 ep = uvc_find_endpoint(&intf->altsetting[0],
1948 stream->header.bEndpointAddress);
1949 if (ep == NULL)
1950 return -EIO;
1951
1952 ret = uvc_init_video_bulk(stream, ep, gfp_flags);
1953 }
1954
1955 if (ret < 0)
1956 return ret;
1957
1958 /* Submit the URBs. */
1959 for_each_uvc_urb(uvc_urb, stream) {
1960 ret = uvc_submit_urb(uvc_urb, gfp_flags);
1961 if (ret < 0) {
1962 dev_err(&stream->intf->dev,
1963 "Failed to submit URB %u (%d).\n",
1964 uvc_urb_index(uvc_urb), ret);
1965 uvc_video_stop_transfer(stream, 1);
1966 return ret;
1967 }
1968 }
1969
1970 /* The Logitech C920 temporarily forgets that it should not be adjusting
1971 * Exposure Absolute during init so restore controls to stored values.
1972 */
1973 if (stream->dev->quirks & UVC_QUIRK_RESTORE_CTRLS_ON_INIT)
1974 uvc_ctrl_restore_values(stream->dev);
1975
1976 return 0;
1977 }
1978
1979 /* --------------------------------------------------------------------------
1980 * Suspend/resume
1981 */
1982
1983 /*
1984 * Stop streaming without disabling the video queue.
1985 *
1986 * To let userspace applications resume without trouble, we must not touch the
1987 * video buffers in any way. We mark the device as frozen to make sure the URB
1988 * completion handler won't try to cancel the queue when we kill the URBs.
1989 */
uvc_video_suspend(struct uvc_streaming * stream)1990 int uvc_video_suspend(struct uvc_streaming *stream)
1991 {
1992 if (!uvc_queue_streaming(&stream->queue))
1993 return 0;
1994
1995 stream->frozen = 1;
1996 uvc_video_stop_transfer(stream, 0);
1997 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
1998 return 0;
1999 }
2000
2001 /*
2002 * Reconfigure the video interface and restart streaming if it was enabled
2003 * before suspend.
2004 *
2005 * If an error occurs, disable the video queue. This will wake all pending
2006 * buffers, making sure userspace applications are notified of the problem
2007 * instead of waiting forever.
2008 */
uvc_video_resume(struct uvc_streaming * stream,int reset)2009 int uvc_video_resume(struct uvc_streaming *stream, int reset)
2010 {
2011 int ret;
2012
2013 /* If the bus has been reset on resume, set the alternate setting to 0.
2014 * This should be the default value, but some devices crash or otherwise
2015 * misbehave if they don't receive a SET_INTERFACE request before any
2016 * other video control request.
2017 */
2018 if (reset)
2019 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
2020
2021 stream->frozen = 0;
2022
2023 uvc_video_clock_reset(stream);
2024
2025 if (!uvc_queue_streaming(&stream->queue))
2026 return 0;
2027
2028 ret = uvc_commit_video(stream, &stream->ctrl);
2029 if (ret < 0)
2030 return ret;
2031
2032 return uvc_video_start_transfer(stream, GFP_NOIO);
2033 }
2034
2035 /* ------------------------------------------------------------------------
2036 * Video device
2037 */
2038
2039 /*
2040 * Initialize the UVC video device by switching to alternate setting 0 and
2041 * retrieve the default format.
2042 *
2043 * Some cameras (namely the Fuji Finepix) set the format and frame
2044 * indexes to zero. The UVC standard doesn't clearly make this a spec
2045 * violation, so try to silently fix the values if possible.
2046 *
2047 * This function is called before registering the device with V4L.
2048 */
uvc_video_init(struct uvc_streaming * stream)2049 int uvc_video_init(struct uvc_streaming *stream)
2050 {
2051 struct uvc_streaming_control *probe = &stream->ctrl;
2052 struct uvc_format *format = NULL;
2053 struct uvc_frame *frame = NULL;
2054 struct uvc_urb *uvc_urb;
2055 unsigned int i;
2056 int ret;
2057
2058 if (stream->nformats == 0) {
2059 dev_info(&stream->intf->dev,
2060 "No supported video formats found.\n");
2061 return -EINVAL;
2062 }
2063
2064 atomic_set(&stream->active, 0);
2065
2066 /* Alternate setting 0 should be the default, yet the XBox Live Vision
2067 * Cam (and possibly other devices) crash or otherwise misbehave if
2068 * they don't receive a SET_INTERFACE request before any other video
2069 * control request.
2070 */
2071 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
2072
2073 /* Set the streaming probe control with default streaming parameters
2074 * retrieved from the device. Webcams that don't support GET_DEF
2075 * requests on the probe control will just keep their current streaming
2076 * parameters.
2077 */
2078 if (uvc_get_video_ctrl(stream, probe, 1, UVC_GET_DEF) == 0)
2079 uvc_set_video_ctrl(stream, probe, 1);
2080
2081 /* Initialize the streaming parameters with the probe control current
2082 * value. This makes sure SET_CUR requests on the streaming commit
2083 * control will always use values retrieved from a successful GET_CUR
2084 * request on the probe control, as required by the UVC specification.
2085 */
2086 ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
2087 if (ret < 0)
2088 return ret;
2089
2090 /* Check if the default format descriptor exists. Use the first
2091 * available format otherwise.
2092 */
2093 for (i = stream->nformats; i > 0; --i) {
2094 format = &stream->format[i-1];
2095 if (format->index == probe->bFormatIndex)
2096 break;
2097 }
2098
2099 if (format->nframes == 0) {
2100 dev_info(&stream->intf->dev,
2101 "No frame descriptor found for the default format.\n");
2102 return -EINVAL;
2103 }
2104
2105 /* Zero bFrameIndex might be correct. Stream-based formats (including
2106 * MPEG-2 TS and DV) do not support frames but have a dummy frame
2107 * descriptor with bFrameIndex set to zero. If the default frame
2108 * descriptor is not found, use the first available frame.
2109 */
2110 for (i = format->nframes; i > 0; --i) {
2111 frame = &format->frame[i-1];
2112 if (frame->bFrameIndex == probe->bFrameIndex)
2113 break;
2114 }
2115
2116 probe->bFormatIndex = format->index;
2117 probe->bFrameIndex = frame->bFrameIndex;
2118
2119 stream->def_format = format;
2120 stream->cur_format = format;
2121 stream->cur_frame = frame;
2122
2123 /* Select the video decoding function */
2124 if (stream->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
2125 if (stream->dev->quirks & UVC_QUIRK_BUILTIN_ISIGHT)
2126 stream->decode = uvc_video_decode_isight;
2127 else if (stream->intf->num_altsetting > 1)
2128 stream->decode = uvc_video_decode_isoc;
2129 else
2130 stream->decode = uvc_video_decode_bulk;
2131 } else {
2132 if (stream->intf->num_altsetting == 1)
2133 stream->decode = uvc_video_encode_bulk;
2134 else {
2135 dev_info(&stream->intf->dev,
2136 "Isochronous endpoints are not supported for video output devices.\n");
2137 return -EINVAL;
2138 }
2139 }
2140
2141 /* Prepare asynchronous work items. */
2142 for_each_uvc_urb(uvc_urb, stream)
2143 INIT_WORK(&uvc_urb->work, uvc_video_copy_data_work);
2144
2145 return 0;
2146 }
2147
uvc_video_start_streaming(struct uvc_streaming * stream)2148 int uvc_video_start_streaming(struct uvc_streaming *stream)
2149 {
2150 int ret;
2151
2152 ret = uvc_video_clock_init(stream);
2153 if (ret < 0)
2154 return ret;
2155
2156 /* Commit the streaming parameters. */
2157 ret = uvc_commit_video(stream, &stream->ctrl);
2158 if (ret < 0)
2159 goto error_commit;
2160
2161 ret = uvc_video_start_transfer(stream, GFP_KERNEL);
2162 if (ret < 0)
2163 goto error_video;
2164
2165 return 0;
2166
2167 error_video:
2168 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
2169 error_commit:
2170 uvc_video_clock_cleanup(stream);
2171
2172 return ret;
2173 }
2174
uvc_video_stop_streaming(struct uvc_streaming * stream)2175 void uvc_video_stop_streaming(struct uvc_streaming *stream)
2176 {
2177 uvc_video_stop_transfer(stream, 1);
2178
2179 if (stream->intf->num_altsetting > 1) {
2180 usb_set_interface(stream->dev->udev, stream->intfnum, 0);
2181 } else {
2182 /* UVC doesn't specify how to inform a bulk-based device
2183 * when the video stream is stopped. Windows sends a
2184 * CLEAR_FEATURE(HALT) request to the video streaming
2185 * bulk endpoint, mimic the same behaviour.
2186 */
2187 unsigned int epnum = stream->header.bEndpointAddress
2188 & USB_ENDPOINT_NUMBER_MASK;
2189 unsigned int dir = stream->header.bEndpointAddress
2190 & USB_ENDPOINT_DIR_MASK;
2191 unsigned int pipe;
2192
2193 pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
2194 usb_clear_halt(stream->dev->udev, pipe);
2195 }
2196
2197 uvc_video_clock_cleanup(stream);
2198 }
2199