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                 /* If the device is disconnected return the buffer to userspace
 139                  * directly. The next QBUF call will fail with -ENODEV.
 140                  */
 141                 buf->state = UVC_BUF_STATE_ERROR;
 142                 vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
 143         }
 144
 145         spin_unlock_irqrestore(&queue->irqlock, flags);
 146 }
 147
 148 static void uvc_buffer_finish(struct vb2_buffer *vb)
 149 {
 150         struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 151         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
 152         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
 153         struct uvc_buffer *buf = uvc_vbuf_to_buffer(vbuf);
 154
 155         if (vb->state == VB2_BUF_STATE_DONE)
 156                 uvc_video_clock_update(stream, vbuf, buf);
 157 }
 158
 159 static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
 160 {
 161         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 162         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
 163         int ret;
 164
 165         lockdep_assert_irqs_enabled();
 166
 167         queue->buf_used = 0;
 168
 169         ret = uvc_video_start_streaming(stream);
 170         if (ret == 0)
 171                 return 0;
 172
 173         spin_lock_irq(&queue->irqlock);
 174         uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
 175         spin_unlock_irq(&queue->irqlock);
 176
 177         return ret;
 178 }
 179
 180 static void uvc_stop_streaming(struct vb2_queue *vq)
 181 {
 182         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 183
 184         lockdep_assert_irqs_enabled();
 185
 186         if (vq->type != V4L2_BUF_TYPE_META_CAPTURE)
 187                 uvc_video_stop_streaming(uvc_queue_to_stream(queue));
 188
 189         spin_lock_irq(&queue->irqlock);
 190         uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
 191         spin_unlock_irq(&queue->irqlock);
 192 }
 193
 194 static const struct vb2_ops uvc_queue_qops = {
 195         .queue_setup = uvc_queue_setup,
 196         .buf_prepare = uvc_buffer_prepare,
 197         .buf_queue = uvc_buffer_queue,
 198         .buf_finish = uvc_buffer_finish,
 199         .wait_prepare = vb2_ops_wait_prepare,
 200         .wait_finish = vb2_ops_wait_finish,
 201         .start_streaming = uvc_start_streaming,
 202         .stop_streaming = uvc_stop_streaming,
 203 };
 204
 205 static const struct vb2_ops uvc_meta_queue_qops = {
 206         .queue_setup = uvc_queue_setup,
 207         .buf_prepare = uvc_buffer_prepare,
 208         .buf_queue = uvc_buffer_queue,
 209         .wait_prepare = vb2_ops_wait_prepare,
 210         .wait_finish = vb2_ops_wait_finish,
 211         .stop_streaming = uvc_stop_streaming,
 212 };
 213
 214 int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
 215                     int drop_corrupted)
 216 {
 217         int ret;
 218
 219         queue->queue.type = type;
 220         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
 221         queue->queue.drv_priv = queue;
 222         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 223         queue->queue.mem_ops = &vb2_vmalloc_memops;
 224         queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
 225                 | V4L2_BUF_FLAG_TSTAMP_SRC_SOE;
 226         queue->queue.lock = &queue->mutex;
 227
 228         switch (type) {
 229         case V4L2_BUF_TYPE_META_CAPTURE:
 230                 queue->queue.ops = &uvc_meta_queue_qops;
 231                 break;
 232         default:
 233                 queue->queue.io_modes |= VB2_DMABUF;
 234                 queue->queue.ops = &uvc_queue_qops;
 235                 break;
 236         }
 237
 238         ret = vb2_queue_init(&queue->queue);
 239         if (ret)
 240                 return ret;
 241
 242         mutex_init(&queue->mutex);
 243         spin_lock_init(&queue->irqlock);
 244         INIT_LIST_HEAD(&queue->irqqueue);
 245         queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0;
 246
 247         return 0;
 248 }
 249
 250 void uvc_queue_release(struct uvc_video_queue *queue)
 251 {
 252         mutex_lock(&queue->mutex);
 253         vb2_queue_release(&queue->queue);
 254         mutex_unlock(&queue->mutex);
 255 }
 256
 257 /* -----------------------------------------------------------------------------
 258  * V4L2 queue operations
 259  */
 260
 261 int uvc_request_buffers(struct uvc_video_queue *queue,
 262                         struct v4l2_requestbuffers *rb)
 263 {
 264         int ret;
 265
 266         mutex_lock(&queue->mutex);
 267         ret = vb2_reqbufs(&queue->queue, rb);
 268         mutex_unlock(&queue->mutex);
 269
 270         return ret ? ret : rb->count;
 271 }
 272
 273 int uvc_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 274 {
 275         int ret;
 276
 277         mutex_lock(&queue->mutex);
 278         ret = vb2_querybuf(&queue->queue, buf);
 279         mutex_unlock(&queue->mutex);
 280
 281         return ret;
 282 }
 283
 284 int uvc_create_buffers(struct uvc_video_queue *queue,
 285                        struct v4l2_create_buffers *cb)
 286 {
 287         int ret;
 288
 289         mutex_lock(&queue->mutex);
 290         ret = vb2_create_bufs(&queue->queue, cb);
 291         mutex_unlock(&queue->mutex);
 292
 293         return ret;
 294 }
 295
 296 int uvc_queue_buffer(struct uvc_video_queue *queue,
 297                      struct media_device *mdev, struct v4l2_buffer *buf)
 298 {
 299         int ret;
 300
 301         mutex_lock(&queue->mutex);
 302         ret = vb2_qbuf(&queue->queue, mdev, buf);
 303         mutex_unlock(&queue->mutex);
 304
 305         return ret;
 306 }
 307
 308 int uvc_export_buffer(struct uvc_video_queue *queue,
 309                       struct v4l2_exportbuffer *exp)
 310 {
 311         int ret;
 312
 313         mutex_lock(&queue->mutex);
 314         ret = vb2_expbuf(&queue->queue, exp);
 315         mutex_unlock(&queue->mutex);
 316
 317         return ret;
 318 }
 319
 320 int uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
 321                        int nonblocking)
 322 {
 323         int ret;
 324
 325         mutex_lock(&queue->mutex);
 326         ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
 327         mutex_unlock(&queue->mutex);
 328
 329         return ret;
 330 }
 331
 332 int uvc_queue_streamon(struct uvc_video_queue *queue, enum v4l2_buf_type type)
 333 {
 334         int ret;
 335
 336         mutex_lock(&queue->mutex);
 337         ret = vb2_streamon(&queue->queue, type);
 338         mutex_unlock(&queue->mutex);
 339
 340         return ret;
 341 }
 342
 343 int uvc_queue_streamoff(struct uvc_video_queue *queue, enum v4l2_buf_type type)
 344 {
 345         int ret;
 346
 347         mutex_lock(&queue->mutex);
 348         ret = vb2_streamoff(&queue->queue, type);
 349         mutex_unlock(&queue->mutex);
 350
 351         return ret;
 352 }
 353
 354 int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
 355 {
 356         return vb2_mmap(&queue->queue, vma);
 357 }
 358
 359 #ifndef CONFIG_MMU
 360 unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
 361                 unsigned long pgoff)
 362 {
 363         return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 364 }
 365 #endif
 366
 367 __poll_t uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
 368                             poll_table *wait)
 369 {
 370         __poll_t ret;
 371
 372         mutex_lock(&queue->mutex);
 373         ret = vb2_poll(&queue->queue, file, wait);
 374         mutex_unlock(&queue->mutex);
 375
 376         return ret;
 377 }
 378
 379 /* -----------------------------------------------------------------------------
 380  *
 381  */
 382
 383 /*
 384  * Check if buffers have been allocated.
 385  */
 386 int uvc_queue_allocated(struct uvc_video_queue *queue)
 387 {
 388         int allocated;
 389
 390         mutex_lock(&queue->mutex);
 391         allocated = vb2_is_busy(&queue->queue);
 392         mutex_unlock(&queue->mutex);
 393
 394         return allocated;
 395 }
 396
 397 /*
 398  * Cancel the video buffers queue.
 399  *
 400  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 401  * wakes them up and removes them from the queue.
 402  *
 403  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 404  * fail with -ENODEV.
 405  *
 406  * This function acquires the irq spinlock and can be called from interrupt
 407  * context.
 408  */
 409 void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 410 {
 411         unsigned long flags;
 412
 413         spin_lock_irqsave(&queue->irqlock, flags);
 414         uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
 415         /* This must be protected by the irqlock spinlock to avoid race
 416          * conditions between uvc_buffer_queue and the disconnection event that
 417          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 418          * blindly replace this logic by checking for the UVC_QUEUE_DISCONNECTED
 419          * state outside the queue code.
 420          */
 421         if (disconnect)
 422                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 423         spin_unlock_irqrestore(&queue->irqlock, flags);
 424 }
 425
 426 /*
 427  * uvc_queue_get_current_buffer: Obtain the current working output buffer
 428  *
 429  * Buffers may span multiple packets, and even URBs, therefore the active buffer
 430  * remains on the queue until the EOF marker.
 431  */
 432 static struct uvc_buffer *
 433 __uvc_queue_get_current_buffer(struct uvc_video_queue *queue)
 434 {
 435         if (list_empty(&queue->irqqueue))
 436                 return NULL;
 437
 438         return list_first_entry(&queue->irqqueue, struct uvc_buffer, queue);
 439 }
 440
 441 struct uvc_buffer *uvc_queue_get_current_buffer(struct uvc_video_queue *queue)
 442 {
 443         struct uvc_buffer *nextbuf;
 444         unsigned long flags;
 445
 446         spin_lock_irqsave(&queue->irqlock, flags);
 447         nextbuf = __uvc_queue_get_current_buffer(queue);
 448         spin_unlock_irqrestore(&queue->irqlock, flags);
 449
 450         return nextbuf;
 451 }
 452
 453 /*
 454  * uvc_queue_buffer_requeue: Requeue a buffer on our internal irqqueue
 455  *
 456  * Reuse a buffer through our internal queue without the need to 'prepare'.
 457  * The buffer will be returned to userspace through the uvc_buffer_queue call if
 458  * the device has been disconnected.
 459  */
 460 static void uvc_queue_buffer_requeue(struct uvc_video_queue *queue,
 461                 struct uvc_buffer *buf)
 462 {
 463         buf->error = 0;
 464         buf->state = UVC_BUF_STATE_QUEUED;
 465         buf->bytesused = 0;
 466         vb2_set_plane_payload(&buf->buf.vb2_buf, 0, 0);
 467
 468         uvc_buffer_queue(&buf->buf.vb2_buf);
 469 }
 470
 471 static void uvc_queue_buffer_complete(struct kref *ref)
 472 {
 473         struct uvc_buffer *buf = container_of(ref, struct uvc_buffer, ref);
 474         struct vb2_buffer *vb = &buf->buf.vb2_buf;
 475         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
 476
 477         if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) {
 478                 uvc_queue_buffer_requeue(queue, buf);
 479                 return;
 480         }
 481
 482         buf->state = buf->error ? UVC_BUF_STATE_ERROR : UVC_BUF_STATE_DONE;
 483         vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused);
 484         vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_DONE);
 485 }
 486
 487 /*
 488  * Release a reference on the buffer. Complete the buffer when the last
 489  * reference is released.
 490  */
 491 void uvc_queue_buffer_release(struct uvc_buffer *buf)
 492 {
 493         kref_put(&buf->ref, uvc_queue_buffer_complete);
 494 }
 495
 496 /*
 497  * Remove this buffer from the queue. Lifetime will persist while async actions
 498  * are still running (if any), and uvc_queue_buffer_release will give the buffer
 499  * back to VB2 when all users have completed.
 500  */
 501 struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
 502                 struct uvc_buffer *buf)
 503 {
 504         struct uvc_buffer *nextbuf;
 505         unsigned long flags;
 506
 507         spin_lock_irqsave(&queue->irqlock, flags);
 508         list_del(&buf->queue);
 509         nextbuf = __uvc_queue_get_current_buffer(queue);
 510         spin_unlock_irqrestore(&queue->irqlock, flags);
 511
 512         uvc_queue_buffer_release(buf);
 513
 514         return nextbuf;
 515 }