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