drivers/media/usb/uvc/uvc_queue.c

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