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 /* -----------------------------------------------------------------------------
  40  * videobuf2 queue operations
  41  */
  42
  43 static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
  44                            unsigned int *nbuffers, unsigned int *nplanes,
  45                            unsigned int sizes[], void *alloc_ctxs[])
  46 {
  47         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
  48         struct uvc_streaming *stream =
  49                         container_of(queue, struct uvc_streaming, queue);
  50
  51         if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
  52                 *nbuffers = UVC_MAX_VIDEO_BUFFERS;
  53
  54         *nplanes = 1;
  55
  56         sizes[0] = stream->ctrl.dwMaxVideoFrameSize;
  57
  58         return 0;
  59 }
  60
  61 static int uvc_buffer_prepare(struct vb2_buffer *vb)
  62 {
  63         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  64         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  65
  66         if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
  67             vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
  68                 uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
  69                 return -EINVAL;
  70         }
  71
  72         if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
  73                 return -ENODEV;
  74
  75         buf->state = UVC_BUF_STATE_QUEUED;
  76         buf->error = 0;
  77         buf->mem = vb2_plane_vaddr(vb, 0);
  78         buf->length = vb2_plane_size(vb, 0);
  79         if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  80                 buf->bytesused = 0;
  81         else
  82                 buf->bytesused = vb2_get_plane_payload(vb, 0);
  83
  84         return 0;
  85 }
  86
  87 static void uvc_buffer_queue(struct vb2_buffer *vb)
  88 {
  89         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  90         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  91         unsigned long flags;
  92
  93         spin_lock_irqsave(&queue->irqlock, flags);
  94         if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
  95                 list_add_tail(&buf->queue, &queue->irqqueue);
  96         } else {
  97                 /* If the device is disconnected return the buffer to userspace
  98                  * directly. The next QBUF call will fail with -ENODEV.
  99                  */
 100                 buf->state = UVC_BUF_STATE_ERROR;
 101                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 102         }
 103
 104         spin_unlock_irqrestore(&queue->irqlock, flags);
 105 }
 106
 107 static int uvc_buffer_finish(struct vb2_buffer *vb)
 108 {
 109         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
 110         struct uvc_streaming *stream =
 111                         container_of(queue, struct uvc_streaming, queue);
 112         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
 113
 114         uvc_video_clock_update(stream, &vb->v4l2_buf, buf);
 115         return 0;
 116 }
 117
 118 static struct vb2_ops uvc_queue_qops = {
 119         .queue_setup = uvc_queue_setup,
 120         .buf_prepare = uvc_buffer_prepare,
 121         .buf_queue = uvc_buffer_queue,
 122         .buf_finish = uvc_buffer_finish,
 123 };
 124
 125 void uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
 126                     int drop_corrupted)
 127 {
 128         queue->queue.type = type;
 129         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
 130         queue->queue.drv_priv = queue;
 131         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 132         queue->queue.ops = &uvc_queue_qops;
 133         queue->queue.mem_ops = &vb2_vmalloc_memops;
 134         vb2_queue_init(&queue->queue);
 135
 136         mutex_init(&queue->mutex);
 137         spin_lock_init(&queue->irqlock);
 138         INIT_LIST_HEAD(&queue->irqqueue);
 139         queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0;
 140 }
 141
 142 /* -----------------------------------------------------------------------------
 143  * V4L2 queue operations
 144  */
 145
 146 int uvc_alloc_buffers(struct uvc_video_queue *queue,
 147                       struct v4l2_requestbuffers *rb)
 148 {
 149         int ret;
 150
 151         mutex_lock(&queue->mutex);
 152         ret = vb2_reqbufs(&queue->queue, rb);
 153         mutex_unlock(&queue->mutex);
 154
 155         return ret ? ret : rb->count;
 156 }
 157
 158 void uvc_free_buffers(struct uvc_video_queue *queue)
 159 {
 160         mutex_lock(&queue->mutex);
 161         vb2_queue_release(&queue->queue);
 162         mutex_unlock(&queue->mutex);
 163 }
 164
 165 int uvc_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 166 {
 167         int ret;
 168
 169         mutex_lock(&queue->mutex);
 170         ret = vb2_querybuf(&queue->queue, buf);
 171         mutex_unlock(&queue->mutex);
 172
 173         return ret;
 174 }
 175
 176 int uvc_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 177 {
 178         int ret;
 179
 180         mutex_lock(&queue->mutex);
 181         ret = vb2_qbuf(&queue->queue, buf);
 182         mutex_unlock(&queue->mutex);
 183
 184         return ret;
 185 }
 186
 187 int uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
 188                        int nonblocking)
 189 {
 190         int ret;
 191
 192         mutex_lock(&queue->mutex);
 193         ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
 194         mutex_unlock(&queue->mutex);
 195
 196         return ret;
 197 }
 198
 199 int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
 200 {
 201         int ret;
 202
 203         mutex_lock(&queue->mutex);
 204         ret = vb2_mmap(&queue->queue, vma);
 205         mutex_unlock(&queue->mutex);
 206
 207         return ret;
 208 }
 209
 210 #ifndef CONFIG_MMU
 211 unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
 212                 unsigned long pgoff)
 213 {
 214         unsigned long ret;
 215
 216         mutex_lock(&queue->mutex);
 217         ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 218         mutex_unlock(&queue->mutex);
 219         return ret;
 220 }
 221 #endif
 222
 223 unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
 224                             poll_table *wait)
 225 {
 226         unsigned int ret;
 227
 228         mutex_lock(&queue->mutex);
 229         ret = vb2_poll(&queue->queue, file, wait);
 230         mutex_unlock(&queue->mutex);
 231
 232         return ret;
 233 }
 234
 235 /* -----------------------------------------------------------------------------
 236  *
 237  */
 238
 239 /*
 240  * Check if buffers have been allocated.
 241  */
 242 int uvc_queue_allocated(struct uvc_video_queue *queue)
 243 {
 244         int allocated;
 245
 246         mutex_lock(&queue->mutex);
 247         allocated = vb2_is_busy(&queue->queue);
 248         mutex_unlock(&queue->mutex);
 249
 250         return allocated;
 251 }
 252
 253 /*
 254  * Enable or disable the video buffers queue.
 255  *
 256  * The queue must be enabled before starting video acquisition and must be
 257  * disabled after stopping it. This ensures that the video buffers queue
 258  * state can be properly initialized before buffers are accessed from the
 259  * interrupt handler.
 260  *
 261  * Enabling the video queue returns -EBUSY if the queue is already enabled.
 262  *
 263  * Disabling the video queue cancels the queue and removes all buffers from
 264  * the main queue.
 265  *
 266  * This function can't be called from interrupt context. Use
 267  * uvc_queue_cancel() instead.
 268  */
 269 int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
 270 {
 271         unsigned long flags;
 272         int ret;
 273
 274         mutex_lock(&queue->mutex);
 275         if (enable) {
 276                 ret = vb2_streamon(&queue->queue, queue->queue.type);
 277                 if (ret < 0)
 278                         goto done;
 279
 280                 queue->buf_used = 0;
 281         } else {
 282                 ret = vb2_streamoff(&queue->queue, queue->queue.type);
 283                 if (ret < 0)
 284                         goto done;
 285
 286                 spin_lock_irqsave(&queue->irqlock, flags);
 287                 INIT_LIST_HEAD(&queue->irqqueue);
 288                 spin_unlock_irqrestore(&queue->irqlock, flags);
 289         }
 290
 291 done:
 292         mutex_unlock(&queue->mutex);
 293         return ret;
 294 }
 295
 296 /*
 297  * Cancel the video buffers queue.
 298  *
 299  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 300  * wakes them up and removes them from the queue.
 301  *
 302  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 303  * fail with -ENODEV.
 304  *
 305  * This function acquires the irq spinlock and can be called from interrupt
 306  * context.
 307  */
 308 void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 309 {
 310         struct uvc_buffer *buf;
 311         unsigned long flags;
 312
 313         spin_lock_irqsave(&queue->irqlock, flags);
 314         while (!list_empty(&queue->irqqueue)) {
 315                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 316                                        queue);
 317                 list_del(&buf->queue);
 318                 buf->state = UVC_BUF_STATE_ERROR;
 319                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 320         }
 321         /* This must be protected by the irqlock spinlock to avoid race
 322          * conditions between uvc_buffer_queue and the disconnection event that
 323          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 324          * blindly replace this logic by checking for the UVC_QUEUE_DISCONNECTED
 325          * state outside the queue code.
 326          */
 327         if (disconnect)
 328                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 329         spin_unlock_irqrestore(&queue->irqlock, flags);
 330 }
 331
 332 struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
 333                 struct uvc_buffer *buf)
 334 {
 335         struct uvc_buffer *nextbuf;
 336         unsigned long flags;
 337
 338         if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) {
 339                 buf->error = 0;
 340                 buf->state = UVC_BUF_STATE_QUEUED;
 341                 vb2_set_plane_payload(&buf->buf, 0, 0);
 342                 return buf;
 343         }
 344
 345         spin_lock_irqsave(&queue->irqlock, flags);
 346         list_del(&buf->queue);
 347         if (!list_empty(&queue->irqqueue))
 348                 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 349                                            queue);
 350         else
 351                 nextbuf = NULL;
 352         spin_unlock_irqrestore(&queue->irqlock, flags);
 353
 354         buf->state = buf->error ? VB2_BUF_STATE_ERROR : UVC_BUF_STATE_DONE;
 355         vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
 356         vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
 357
 358         return nextbuf;
 359 }