drivers/media/usb/uvc/uvc_queue.c

   1 /*
   2  *      uvc_queue.c  --  USB Video Class driver - Buffers management
   3  *
   4  *      Copyright (C) 2005-2010
   5  *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
   6  *
   7  *      This program is free software; you can redistribute it and/or modify
   8  *      it under the terms of the GNU General Public License as published by
   9  *      the Free Software Foundation; either version 2 of the License, or
  10  *      (at your option) any later version.
  11  *
  12  */
  13
  14 #include <linux/atomic.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/list.h>
  18 #include <linux/module.h>
  19 #include <linux/usb.h>
  20 #include <linux/videodev2.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/wait.h>
  23 #include <media/videobuf2-vmalloc.h>
  24
  25 #include "uvcvideo.h"
  26
  27 /* ------------------------------------------------------------------------
  28  * Video buffers queue management.
  29  *
  30  * Video queues is initialized by uvc_queue_init(). The function performs
  31  * basic initialization of the uvc_video_queue struct and never fails.
  32  *
  33  * Video buffers are managed by videobuf2. The driver uses a mutex to protect
  34  * the videobuf2 queue operations by serializing calls to videobuf2 and a
  35  * spinlock to protect the IRQ queue that holds the buffers to be processed by
  36  * the driver.
  37  */
  38
  39 static inline struct uvc_streaming *
  40 uvc_queue_to_stream(struct uvc_video_queue *queue)
  41 {
  42         return container_of(queue, struct uvc_streaming, queue);
  43 }
  44
  45 /* -----------------------------------------------------------------------------
  46  * videobuf2 queue operations
  47  */
  48
  49 static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
  50                            unsigned int *nbuffers, unsigned int *nplanes,
  51                            unsigned int sizes[], void *alloc_ctxs[])
  52 {
  53         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
  54         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
  55
  56         /* Make sure the image size is large enough. */
  57         if (fmt && fmt->fmt.pix.sizeimage < stream->ctrl.dwMaxVideoFrameSize)
  58                 return -EINVAL;
  59
  60         *nplanes = 1;
  61
  62         sizes[0] = fmt ? fmt->fmt.pix.sizeimage
  63                  : stream->ctrl.dwMaxVideoFrameSize;
  64
  65         return 0;
  66 }
  67
  68 static int uvc_buffer_prepare(struct vb2_buffer *vb)
  69 {
  70         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  71         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  72
  73         if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
  74             vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
  75                 uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
  76                 return -EINVAL;
  77         }
  78
  79         if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
  80                 return -ENODEV;
  81
  82         buf->state = UVC_BUF_STATE_QUEUED;
  83         buf->error = 0;
  84         buf->mem = vb2_plane_vaddr(vb, 0);
  85         buf->length = vb2_plane_size(vb, 0);
  86         if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  87                 buf->bytesused = 0;
  88         else
  89                 buf->bytesused = vb2_get_plane_payload(vb, 0);
  90
  91         return 0;
  92 }
  93
  94 static void uvc_buffer_queue(struct vb2_buffer *vb)
  95 {
  96         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  97         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  98         unsigned long flags;
  99
 100         spin_lock_irqsave(&queue->irqlock, flags);
 101         if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
 102                 list_add_tail(&buf->queue, &queue->irqqueue);
 103         } else {
 104                 /* If the device is disconnected return the buffer to userspace
 105                  * directly. The next QBUF call will fail with -ENODEV.
 106                  */
 107                 buf->state = UVC_BUF_STATE_ERROR;
 108                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 109         }
 110
 111         spin_unlock_irqrestore(&queue->irqlock, flags);
 112 }
 113
 114 static void uvc_buffer_finish(struct vb2_buffer *vb)
 115 {
 116         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
 117         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
 118         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
 119
 120         if (vb->state == VB2_BUF_STATE_DONE)
 121                 uvc_video_clock_update(stream, &vb->v4l2_buf, buf);
 122 }
 123
 124 static void uvc_wait_prepare(struct vb2_queue *vq)
 125 {
 126         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 127
 128         mutex_unlock(&queue->mutex);
 129 }
 130
 131 static void uvc_wait_finish(struct vb2_queue *vq)
 132 {
 133         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 134
 135         mutex_lock(&queue->mutex);
 136 }
 137
 138 static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
 139 {
 140         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 141         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
 142
 143         queue->buf_used = 0;
 144
 145         return uvc_video_enable(stream, 1);
 146 }
 147
 148 static void uvc_stop_streaming(struct vb2_queue *vq)
 149 {
 150         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 151         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
 152         unsigned long flags;
 153
 154         uvc_video_enable(stream, 0);
 155
 156         spin_lock_irqsave(&queue->irqlock, flags);
 157         INIT_LIST_HEAD(&queue->irqqueue);
 158         spin_unlock_irqrestore(&queue->irqlock, flags);
 159 }
 160
 161 static struct vb2_ops uvc_queue_qops = {
 162         .queue_setup = uvc_queue_setup,
 163         .buf_prepare = uvc_buffer_prepare,
 164         .buf_queue = uvc_buffer_queue,
 165         .buf_finish = uvc_buffer_finish,
 166         .wait_prepare = uvc_wait_prepare,
 167         .wait_finish = uvc_wait_finish,
 168         .start_streaming = uvc_start_streaming,
 169         .stop_streaming = uvc_stop_streaming,
 170 };
 171
 172 int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
 173                     int drop_corrupted)
 174 {
 175         int ret;
 176
 177         queue->queue.type = type;
 178         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 179         queue->queue.drv_priv = queue;
 180         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 181         queue->queue.ops = &uvc_queue_qops;
 182         queue->queue.mem_ops = &vb2_vmalloc_memops;
 183         queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
 184                 | V4L2_BUF_FLAG_TSTAMP_SRC_SOE;
 185         ret = vb2_queue_init(&queue->queue);
 186         if (ret)
 187                 return ret;
 188
 189         mutex_init(&queue->mutex);
 190         spin_lock_init(&queue->irqlock);
 191         INIT_LIST_HEAD(&queue->irqqueue);
 192         queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0;
 193
 194         return 0;
 195 }
 196
 197 /* -----------------------------------------------------------------------------
 198  * V4L2 queue operations
 199  */
 200
 201 int uvc_alloc_buffers(struct uvc_video_queue *queue,
 202                       struct v4l2_requestbuffers *rb)
 203 {
 204         int ret;
 205
 206         mutex_lock(&queue->mutex);
 207         ret = vb2_reqbufs(&queue->queue, rb);
 208         mutex_unlock(&queue->mutex);
 209
 210         return ret ? ret : rb->count;
 211 }
 212
 213 void uvc_free_buffers(struct uvc_video_queue *queue)
 214 {
 215         mutex_lock(&queue->mutex);
 216         vb2_queue_release(&queue->queue);
 217         mutex_unlock(&queue->mutex);
 218 }
 219
 220 int uvc_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 221 {
 222         int ret;
 223
 224         mutex_lock(&queue->mutex);
 225         ret = vb2_querybuf(&queue->queue, buf);
 226         mutex_unlock(&queue->mutex);
 227
 228         return ret;
 229 }
 230
 231 int uvc_create_buffers(struct uvc_video_queue *queue,
 232                        struct v4l2_create_buffers *cb)
 233 {
 234         int ret;
 235
 236         mutex_lock(&queue->mutex);
 237         ret = vb2_create_bufs(&queue->queue, cb);
 238         mutex_unlock(&queue->mutex);
 239
 240         return ret;
 241 }
 242
 243 int uvc_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 244 {
 245         int ret;
 246
 247         mutex_lock(&queue->mutex);
 248         ret = vb2_qbuf(&queue->queue, buf);
 249         mutex_unlock(&queue->mutex);
 250
 251         return ret;
 252 }
 253
 254 int uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
 255                        int nonblocking)
 256 {
 257         int ret;
 258
 259         mutex_lock(&queue->mutex);
 260         ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
 261         mutex_unlock(&queue->mutex);
 262
 263         return ret;
 264 }
 265
 266 int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
 267 {
 268         int ret;
 269
 270         mutex_lock(&queue->mutex);
 271         ret = vb2_mmap(&queue->queue, vma);
 272         mutex_unlock(&queue->mutex);
 273
 274         return ret;
 275 }
 276
 277 #ifndef CONFIG_MMU
 278 unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
 279                 unsigned long pgoff)
 280 {
 281         unsigned long ret;
 282
 283         mutex_lock(&queue->mutex);
 284         ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 285         mutex_unlock(&queue->mutex);
 286         return ret;
 287 }
 288 #endif
 289
 290 unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
 291                             poll_table *wait)
 292 {
 293         unsigned int ret;
 294
 295         mutex_lock(&queue->mutex);
 296         ret = vb2_poll(&queue->queue, file, wait);
 297         mutex_unlock(&queue->mutex);
 298
 299         return ret;
 300 }
 301
 302 /* -----------------------------------------------------------------------------
 303  *
 304  */
 305
 306 /*
 307  * Check if buffers have been allocated.
 308  */
 309 int uvc_queue_allocated(struct uvc_video_queue *queue)
 310 {
 311         int allocated;
 312
 313         mutex_lock(&queue->mutex);
 314         allocated = vb2_is_busy(&queue->queue);
 315         mutex_unlock(&queue->mutex);
 316
 317         return allocated;
 318 }
 319
 320 /*
 321  * Enable or disable the video buffers queue.
 322  *
 323  * The queue must be enabled before starting video acquisition and must be
 324  * disabled after stopping it. This ensures that the video buffers queue
 325  * state can be properly initialized before buffers are accessed from the
 326  * interrupt handler.
 327  *
 328  * Enabling the video queue returns -EBUSY if the queue is already enabled.
 329  *
 330  * Disabling the video queue cancels the queue and removes all buffers from
 331  * the main queue.
 332  *
 333  * This function can't be called from interrupt context. Use
 334  * uvc_queue_cancel() instead.
 335  */
 336 int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
 337 {
 338         int ret;
 339
 340         mutex_lock(&queue->mutex);
 341
 342         if (enable)
 343                 ret = vb2_streamon(&queue->queue, queue->queue.type);
 344         else
 345                 ret = vb2_streamoff(&queue->queue, queue->queue.type);
 346
 347         mutex_unlock(&queue->mutex);
 348         return ret;
 349 }
 350
 351 /*
 352  * Cancel the video buffers queue.
 353  *
 354  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 355  * wakes them up and removes them from the queue.
 356  *
 357  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 358  * fail with -ENODEV.
 359  *
 360  * This function acquires the irq spinlock and can be called from interrupt
 361  * context.
 362  */
 363 void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 364 {
 365         struct uvc_buffer *buf;
 366         unsigned long flags;
 367
 368         spin_lock_irqsave(&queue->irqlock, flags);
 369         while (!list_empty(&queue->irqqueue)) {
 370                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 371                                        queue);
 372                 list_del(&buf->queue);
 373                 buf->state = UVC_BUF_STATE_ERROR;
 374                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 375         }
 376         /* This must be protected by the irqlock spinlock to avoid race
 377          * conditions between uvc_buffer_queue and the disconnection event that
 378          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 379          * blindly replace this logic by checking for the UVC_QUEUE_DISCONNECTED
 380          * state outside the queue code.
 381          */
 382         if (disconnect)
 383                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 384         spin_unlock_irqrestore(&queue->irqlock, flags);
 385 }
 386
 387 struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
 388                 struct uvc_buffer *buf)
 389 {
 390         struct uvc_buffer *nextbuf;
 391         unsigned long flags;
 392
 393         if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) {
 394                 buf->error = 0;
 395                 buf->state = UVC_BUF_STATE_QUEUED;
 396                 buf->bytesused = 0;
 397                 vb2_set_plane_payload(&buf->buf, 0, 0);
 398                 return buf;
 399         }
 400
 401         spin_lock_irqsave(&queue->irqlock, flags);
 402         list_del(&buf->queue);
 403         if (!list_empty(&queue->irqqueue))
 404                 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 405                                            queue);
 406         else
 407                 nextbuf = NULL;
 408         spin_unlock_irqrestore(&queue->irqlock, flags);
 409
 410         buf->state = buf->error ? VB2_BUF_STATE_ERROR : UVC_BUF_STATE_DONE;
 411         vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
 412         vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
 413
 414         return nextbuf;
 415 }