root/drivers/media/usb/uvc/uvc_queue.c

DEFINITIONS

1. uvc_queue_to_stream
2. uvc_vbuf_to_buffer
3. uvc_queue_return_buffers
4. uvc_queue_setup
5. uvc_buffer_prepare
6. uvc_buffer_queue
7. uvc_buffer_finish
8. uvc_start_streaming
9. uvc_stop_streaming
10. uvc_queue_init
11. uvc_queue_release
12. uvc_request_buffers
13. uvc_query_buffer
14. uvc_create_buffers
15. uvc_queue_buffer
16. uvc_export_buffer
17. uvc_dequeue_buffer
18. uvc_queue_streamon
19. uvc_queue_streamoff
20. uvc_queue_mmap
21. uvc_queue_get_unmapped_area
22. uvc_queue_poll
23. uvc_queue_allocated
24. uvc_queue_cancel
25. __uvc_queue_get_current_buffer
26. uvc_queue_get_current_buffer
27. uvc_queue_buffer_requeue
28. uvc_queue_buffer_complete
29. uvc_queue_buffer_release
30. uvc_queue_next_buffer

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      uvc_queue.c  --  USB Video Class driver - Buffers management
   4  *
   5  *      Copyright (C) 2005-2010
   6  *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
   7  */
   8 
   9 #include <linux/atomic.h>
  10 #include <linux/kernel.h>
  11 #include <linux/mm.h>
  12 #include <linux/list.h>
  13 #include <linux/module.h>
  14 #include <linux/usb.h>
  15 #include <linux/videodev2.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/wait.h>
  18 #include <media/videobuf2-v4l2.h>
  19 #include <media/videobuf2-vmalloc.h>
  20 
  21 #include "uvcvideo.h"
  22 
  23 /* ------------------------------------------------------------------------
  24  * Video buffers queue management.
  25  *
  26  * Video queues is initialized by uvc_queue_init(). The function performs
  27  * basic initialization of the uvc_video_queue struct and never fails.
  28  *
  29  * Video buffers are managed by videobuf2. The driver uses a mutex to protect
  30  * the videobuf2 queue operations by serializing calls to videobuf2 and a
  31  * spinlock to protect the IRQ queue that holds the buffers to be processed by
  32  * the driver.
  33  */
  34 
  35 static inline struct uvc_streaming *
  36 uvc_queue_to_stream(struct uvc_video_queue *queue)
  37 {
  38         return container_of(queue, struct uvc_streaming, queue);
  39 }
  40 
  41 static inline struct uvc_buffer *uvc_vbuf_to_buffer(struct vb2_v4l2_buffer *buf)
  42 {
  43         return container_of(buf, struct uvc_buffer, buf);
  44 }
  45 
  46 /*
  47  * Return all queued buffers to videobuf2 in the requested state.
  48  *
  49  * This function must be called with the queue spinlock held.
  50  */
  51 static void uvc_queue_return_buffers(struct uvc_video_queue *queue,
  52                                enum uvc_buffer_state state)
  53 {
  54         enum vb2_buffer_state vb2_state = state == UVC_BUF_STATE_ERROR
  55                                         ? VB2_BUF_STATE_ERROR
  56                                         : VB2_BUF_STATE_QUEUED;
  57 
  58         while (!list_empty(&queue->irqqueue)) {
  59                 struct uvc_buffer *buf = list_first_entry(&queue->irqqueue,
  60                                                           struct uvc_buffer,
  61                                                           queue);
  62                 list_del(&buf->queue);
  63                 buf->state = state;
  64                 vb2_buffer_done(&buf->buf.vb2_buf, vb2_state);
  65         }
  66 }
  67 
  68 /* -----------------------------------------------------------------------------
  69  * videobuf2 queue operations
  70  */
  71 
  72 static int uvc_queue_setup(struct vb2_queue *vq,
  73                            unsigned int *nbuffers, unsigned int *nplanes,
  74                            unsigned int sizes[], struct device *alloc_devs[])
  75 {
  76         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
  77         struct uvc_streaming *stream;
  78         unsigned int size;
  79 
  80         switch (vq->type) {
  81         case V4L2_BUF_TYPE_META_CAPTURE:
  82                 size = UVC_METATADA_BUF_SIZE;
  83                 break;
  84 
  85         default:
  86                 stream = uvc_queue_to_stream(queue);
  87                 size = stream->ctrl.dwMaxVideoFrameSize;
  88                 break;
  89         }
  90 
  91         /*
  92          * When called with plane sizes, validate them. The driver supports
  93          * single planar formats only, and requires buffers to be large enough
  94          * to store a complete frame.
  95          */
  96         if (*nplanes)
  97                 return *nplanes != 1 || sizes[0] < size ? -EINVAL : 0;
  98 
  99         *nplanes = 1;
 100         sizes[0] = size;
 101         return 0;
 102 }
 103 
 104 static int uvc_buffer_prepare(struct vb2_buffer *vb)
 105 {
 106         struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 107         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
 108         struct uvc_buffer *buf = uvc_vbuf_to_buffer(vbuf);
 109 
 110         if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
 111             vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
 112                 uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
 113                 return -EINVAL;
 114         }
 115 
 116         if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
 117                 return -ENODEV;
 118 
 119         buf->state = UVC_BUF_STATE_QUEUED;
 120         buf->error = 0;
 121         buf->mem = vb2_plane_vaddr(vb, 0);
 122         buf->length = vb2_plane_size(vb, 0);
 123         if (vb->type != V4L2_BUF_TYPE_VIDEO_OUTPUT)
 124                 buf->bytesused = 0;
 125         else
 126                 buf->bytesused = vb2_get_plane_payload(vb, 0);
 127 
 128         return 0;
 129 }
 130 
 131 static void uvc_buffer_queue(struct vb2_buffer *vb)
 132 {
 133         struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 134         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
 135         struct uvc_buffer *buf = uvc_vbuf_to_buffer(vbuf);
 136         unsigned long flags;
 137 
 138         spin_lock_irqsave(&queue->irqlock, flags);
 139         if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
 140                 kref_init(&buf->ref);
 141                 list_add_tail(&buf->queue, &queue->irqqueue);
 142         } else {
 143                 /* If the device is disconnected return the buffer to userspace
 144                  * directly. The next QBUF call will fail with -ENODEV.
 145                  */
 146                 buf->state = UVC_BUF_STATE_ERROR;
 147                 vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
 148         }
 149 
 150         spin_unlock_irqrestore(&queue->irqlock, flags);
 151 }
 152 
 153 static void uvc_buffer_finish(struct vb2_buffer *vb)
 154 {
 155         struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 156         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
 157         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
 158         struct uvc_buffer *buf = uvc_vbuf_to_buffer(vbuf);
 159 
 160         if (vb->state == VB2_BUF_STATE_DONE)
 161                 uvc_video_clock_update(stream, vbuf, buf);
 162 }
 163 
 164 static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
 165 {
 166         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 167         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
 168         int ret;
 169 
 170         lockdep_assert_irqs_enabled();
 171 
 172         queue->buf_used = 0;
 173 
 174         ret = uvc_video_start_streaming(stream);
 175         if (ret == 0)
 176                 return 0;
 177 
 178         spin_lock_irq(&queue->irqlock);
 179         uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
 180         spin_unlock_irq(&queue->irqlock);
 181 
 182         return ret;
 183 }
 184 
 185 static void uvc_stop_streaming(struct vb2_queue *vq)
 186 {
 187         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 188 
 189         lockdep_assert_irqs_enabled();
 190 
 191         if (vq->type != V4L2_BUF_TYPE_META_CAPTURE)
 192                 uvc_video_stop_streaming(uvc_queue_to_stream(queue));
 193 
 194         spin_lock_irq(&queue->irqlock);
 195         uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
 196         spin_unlock_irq(&queue->irqlock);
 197 }
 198 
 199 static const struct vb2_ops uvc_queue_qops = {
 200         .queue_setup = uvc_queue_setup,
 201         .buf_prepare = uvc_buffer_prepare,
 202         .buf_queue = uvc_buffer_queue,
 203         .buf_finish = uvc_buffer_finish,
 204         .wait_prepare = vb2_ops_wait_prepare,
 205         .wait_finish = vb2_ops_wait_finish,
 206         .start_streaming = uvc_start_streaming,
 207         .stop_streaming = uvc_stop_streaming,
 208 };
 209 
 210 static const struct vb2_ops uvc_meta_queue_qops = {
 211         .queue_setup = uvc_queue_setup,
 212         .buf_prepare = uvc_buffer_prepare,
 213         .buf_queue = uvc_buffer_queue,
 214         .wait_prepare = vb2_ops_wait_prepare,
 215         .wait_finish = vb2_ops_wait_finish,
 216         .stop_streaming = uvc_stop_streaming,
 217 };
 218 
 219 int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
 220                     int drop_corrupted)
 221 {
 222         int ret;
 223 
 224         queue->queue.type = type;
 225         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
 226         queue->queue.drv_priv = queue;
 227         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 228         queue->queue.mem_ops = &vb2_vmalloc_memops;
 229         queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
 230                 | V4L2_BUF_FLAG_TSTAMP_SRC_SOE;
 231         queue->queue.lock = &queue->mutex;
 232 
 233         switch (type) {
 234         case V4L2_BUF_TYPE_META_CAPTURE:
 235                 queue->queue.ops = &uvc_meta_queue_qops;
 236                 break;
 237         default:
 238                 queue->queue.io_modes |= VB2_DMABUF;
 239                 queue->queue.ops = &uvc_queue_qops;
 240                 break;
 241         }
 242 
 243         ret = vb2_queue_init(&queue->queue);
 244         if (ret)
 245                 return ret;
 246 
 247         mutex_init(&queue->mutex);
 248         spin_lock_init(&queue->irqlock);
 249         INIT_LIST_HEAD(&queue->irqqueue);
 250         queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0;
 251 
 252         return 0;
 253 }
 254 
 255 void uvc_queue_release(struct uvc_video_queue *queue)
 256 {
 257         mutex_lock(&queue->mutex);
 258         vb2_queue_release(&queue->queue);
 259         mutex_unlock(&queue->mutex);
 260 }
 261 
 262 /* -----------------------------------------------------------------------------
 263  * V4L2 queue operations
 264  */
 265 
 266 int uvc_request_buffers(struct uvc_video_queue *queue,
 267                         struct v4l2_requestbuffers *rb)
 268 {
 269         int ret;
 270 
 271         mutex_lock(&queue->mutex);
 272         ret = vb2_reqbufs(&queue->queue, rb);
 273         mutex_unlock(&queue->mutex);
 274 
 275         return ret ? ret : rb->count;
 276 }
 277 
 278 int uvc_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 279 {
 280         int ret;
 281 
 282         mutex_lock(&queue->mutex);
 283         ret = vb2_querybuf(&queue->queue, buf);
 284         mutex_unlock(&queue->mutex);
 285 
 286         return ret;
 287 }
 288 
 289 int uvc_create_buffers(struct uvc_video_queue *queue,
 290                        struct v4l2_create_buffers *cb)
 291 {
 292         int ret;
 293 
 294         mutex_lock(&queue->mutex);
 295         ret = vb2_create_bufs(&queue->queue, cb);
 296         mutex_unlock(&queue->mutex);
 297 
 298         return ret;
 299 }
 300 
 301 int uvc_queue_buffer(struct uvc_video_queue *queue,
 302                      struct media_device *mdev, struct v4l2_buffer *buf)
 303 {
 304         int ret;
 305 
 306         mutex_lock(&queue->mutex);
 307         ret = vb2_qbuf(&queue->queue, mdev, buf);
 308         mutex_unlock(&queue->mutex);
 309 
 310         return ret;
 311 }
 312 
 313 int uvc_export_buffer(struct uvc_video_queue *queue,
 314                       struct v4l2_exportbuffer *exp)
 315 {
 316         int ret;
 317 
 318         mutex_lock(&queue->mutex);
 319         ret = vb2_expbuf(&queue->queue, exp);
 320         mutex_unlock(&queue->mutex);
 321 
 322         return ret;
 323 }
 324 
 325 int uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
 326                        int nonblocking)
 327 {
 328         int ret;
 329 
 330         mutex_lock(&queue->mutex);
 331         ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
 332         mutex_unlock(&queue->mutex);
 333 
 334         return ret;
 335 }
 336 
 337 int uvc_queue_streamon(struct uvc_video_queue *queue, enum v4l2_buf_type type)
 338 {
 339         int ret;
 340 
 341         mutex_lock(&queue->mutex);
 342         ret = vb2_streamon(&queue->queue, type);
 343         mutex_unlock(&queue->mutex);
 344 
 345         return ret;
 346 }
 347 
 348 int uvc_queue_streamoff(struct uvc_video_queue *queue, enum v4l2_buf_type type)
 349 {
 350         int ret;
 351 
 352         mutex_lock(&queue->mutex);
 353         ret = vb2_streamoff(&queue->queue, type);
 354         mutex_unlock(&queue->mutex);
 355 
 356         return ret;
 357 }
 358 
 359 int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
 360 {
 361         return vb2_mmap(&queue->queue, vma);
 362 }
 363 
 364 #ifndef CONFIG_MMU
 365 unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
 366                 unsigned long pgoff)
 367 {
 368         return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 369 }
 370 #endif
 371 
 372 __poll_t uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
 373                             poll_table *wait)
 374 {
 375         __poll_t ret;
 376 
 377         mutex_lock(&queue->mutex);
 378         ret = vb2_poll(&queue->queue, file, wait);
 379         mutex_unlock(&queue->mutex);
 380 
 381         return ret;
 382 }
 383 
 384 /* -----------------------------------------------------------------------------
 385  *
 386  */
 387 
 388 /*
 389  * Check if buffers have been allocated.
 390  */
 391 int uvc_queue_allocated(struct uvc_video_queue *queue)
 392 {
 393         int allocated;
 394 
 395         mutex_lock(&queue->mutex);
 396         allocated = vb2_is_busy(&queue->queue);
 397         mutex_unlock(&queue->mutex);
 398 
 399         return allocated;
 400 }
 401 
 402 /*
 403  * Cancel the video buffers queue.
 404  *
 405  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 406  * wakes them up and removes them from the queue.
 407  *
 408  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 409  * fail with -ENODEV.
 410  *
 411  * This function acquires the irq spinlock and can be called from interrupt
 412  * context.
 413  */
 414 void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 415 {
 416         unsigned long flags;
 417 
 418         spin_lock_irqsave(&queue->irqlock, flags);
 419         uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
 420         /* This must be protected by the irqlock spinlock to avoid race
 421          * conditions between uvc_buffer_queue and the disconnection event that
 422          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 423          * blindly replace this logic by checking for the UVC_QUEUE_DISCONNECTED
 424          * state outside the queue code.
 425          */
 426         if (disconnect)
 427                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 428         spin_unlock_irqrestore(&queue->irqlock, flags);
 429 }
 430 
 431 /*
 432  * uvc_queue_get_current_buffer: Obtain the current working output buffer
 433  *
 434  * Buffers may span multiple packets, and even URBs, therefore the active buffer
 435  * remains on the queue until the EOF marker.
 436  */
 437 static struct uvc_buffer *
 438 __uvc_queue_get_current_buffer(struct uvc_video_queue *queue)
 439 {
 440         if (list_empty(&queue->irqqueue))
 441                 return NULL;
 442 
 443         return list_first_entry(&queue->irqqueue, struct uvc_buffer, queue);
 444 }
 445 
 446 struct uvc_buffer *uvc_queue_get_current_buffer(struct uvc_video_queue *queue)
 447 {
 448         struct uvc_buffer *nextbuf;
 449         unsigned long flags;
 450 
 451         spin_lock_irqsave(&queue->irqlock, flags);
 452         nextbuf = __uvc_queue_get_current_buffer(queue);
 453         spin_unlock_irqrestore(&queue->irqlock, flags);
 454 
 455         return nextbuf;
 456 }
 457 
 458 /*
 459  * uvc_queue_buffer_requeue: Requeue a buffer on our internal irqqueue
 460  *
 461  * Reuse a buffer through our internal queue without the need to 'prepare'.
 462  * The buffer will be returned to userspace through the uvc_buffer_queue call if
 463  * the device has been disconnected.
 464  */
 465 static void uvc_queue_buffer_requeue(struct uvc_video_queue *queue,
 466                 struct uvc_buffer *buf)
 467 {
 468         buf->error = 0;
 469         buf->state = UVC_BUF_STATE_QUEUED;
 470         buf->bytesused = 0;
 471         vb2_set_plane_payload(&buf->buf.vb2_buf, 0, 0);
 472 
 473         uvc_buffer_queue(&buf->buf.vb2_buf);
 474 }
 475 
 476 static void uvc_queue_buffer_complete(struct kref *ref)
 477 {
 478         struct uvc_buffer *buf = container_of(ref, struct uvc_buffer, ref);
 479         struct vb2_buffer *vb = &buf->buf.vb2_buf;
 480         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
 481 
 482         if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) {
 483                 uvc_queue_buffer_requeue(queue, buf);
 484                 return;
 485         }
 486 
 487         buf->state = buf->error ? UVC_BUF_STATE_ERROR : UVC_BUF_STATE_DONE;
 488         vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused);
 489         vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_DONE);
 490 }
 491 
 492 /*
 493  * Release a reference on the buffer. Complete the buffer when the last
 494  * reference is released.
 495  */
 496 void uvc_queue_buffer_release(struct uvc_buffer *buf)
 497 {
 498         kref_put(&buf->ref, uvc_queue_buffer_complete);
 499 }
 500 
 501 /*
 502  * Remove this buffer from the queue. Lifetime will persist while async actions
 503  * are still running (if any), and uvc_queue_buffer_release will give the buffer
 504  * back to VB2 when all users have completed.
 505  */
 506 struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
 507                 struct uvc_buffer *buf)
 508 {
 509         struct uvc_buffer *nextbuf;
 510         unsigned long flags;
 511 
 512         spin_lock_irqsave(&queue->irqlock, flags);
 513         list_del(&buf->queue);
 514         nextbuf = __uvc_queue_get_current_buffer(queue);
 515         spin_unlock_irqrestore(&queue->irqlock, flags);
 516 
 517         uvc_queue_buffer_release(buf);
 518 
 519         return nextbuf;
 520 }