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 void uvc_wait_prepare(struct vb2_queue *vq)
 119 {
 120         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 121
 122         mutex_unlock(&queue->mutex);
 123 }
 124
 125 static void uvc_wait_finish(struct vb2_queue *vq)
 126 {
 127         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 128
 129         mutex_lock(&queue->mutex);
 130 }
 131
 132 static struct vb2_ops uvc_queue_qops = {
 133         .queue_setup = uvc_queue_setup,
 134         .buf_prepare = uvc_buffer_prepare,
 135         .buf_queue = uvc_buffer_queue,
 136         .buf_finish = uvc_buffer_finish,
 137         .wait_prepare = uvc_wait_prepare,
 138         .wait_finish = uvc_wait_finish,
 139 };
 140
 141 int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
 142                     int drop_corrupted)
 143 {
 144         int ret;
 145
 146         queue->queue.type = type;
 147         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 148         queue->queue.drv_priv = queue;
 149         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 150         queue->queue.ops = &uvc_queue_qops;
 151         queue->queue.mem_ops = &vb2_vmalloc_memops;
 152         queue->queue.timestamp_type = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
 153         ret = vb2_queue_init(&queue->queue);
 154         if (ret)
 155                 return ret;
 156
 157         mutex_init(&queue->mutex);
 158         spin_lock_init(&queue->irqlock);
 159         INIT_LIST_HEAD(&queue->irqqueue);
 160         queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0;
 161
 162         return 0;
 163 }
 164
 165 /* -----------------------------------------------------------------------------
 166  * V4L2 queue operations
 167  */
 168
 169 int uvc_alloc_buffers(struct uvc_video_queue *queue,
 170                       struct v4l2_requestbuffers *rb)
 171 {
 172         int ret;
 173
 174         mutex_lock(&queue->mutex);
 175         ret = vb2_reqbufs(&queue->queue, rb);
 176         mutex_unlock(&queue->mutex);
 177
 178         return ret ? ret : rb->count;
 179 }
 180
 181 void uvc_free_buffers(struct uvc_video_queue *queue)
 182 {
 183         mutex_lock(&queue->mutex);
 184         vb2_queue_release(&queue->queue);
 185         mutex_unlock(&queue->mutex);
 186 }
 187
 188 int uvc_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 189 {
 190         int ret;
 191
 192         mutex_lock(&queue->mutex);
 193         ret = vb2_querybuf(&queue->queue, buf);
 194         mutex_unlock(&queue->mutex);
 195
 196         return ret;
 197 }
 198
 199 int uvc_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 200 {
 201         int ret;
 202
 203         mutex_lock(&queue->mutex);
 204         ret = vb2_qbuf(&queue->queue, buf);
 205         mutex_unlock(&queue->mutex);
 206
 207         return ret;
 208 }
 209
 210 int uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
 211                        int nonblocking)
 212 {
 213         int ret;
 214
 215         mutex_lock(&queue->mutex);
 216         ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
 217         mutex_unlock(&queue->mutex);
 218
 219         return ret;
 220 }
 221
 222 int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
 223 {
 224         int ret;
 225
 226         mutex_lock(&queue->mutex);
 227         ret = vb2_mmap(&queue->queue, vma);
 228         mutex_unlock(&queue->mutex);
 229
 230         return ret;
 231 }
 232
 233 #ifndef CONFIG_MMU
 234 unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
 235                 unsigned long pgoff)
 236 {
 237         unsigned long ret;
 238
 239         mutex_lock(&queue->mutex);
 240         ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 241         mutex_unlock(&queue->mutex);
 242         return ret;
 243 }
 244 #endif
 245
 246 unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
 247                             poll_table *wait)
 248 {
 249         unsigned int ret;
 250
 251         mutex_lock(&queue->mutex);
 252         ret = vb2_poll(&queue->queue, file, wait);
 253         mutex_unlock(&queue->mutex);
 254
 255         return ret;
 256 }
 257
 258 /* -----------------------------------------------------------------------------
 259  *
 260  */
 261
 262 /*
 263  * Check if buffers have been allocated.
 264  */
 265 int uvc_queue_allocated(struct uvc_video_queue *queue)
 266 {
 267         int allocated;
 268
 269         mutex_lock(&queue->mutex);
 270         allocated = vb2_is_busy(&queue->queue);
 271         mutex_unlock(&queue->mutex);
 272
 273         return allocated;
 274 }
 275
 276 /*
 277  * Enable or disable the video buffers queue.
 278  *
 279  * The queue must be enabled before starting video acquisition and must be
 280  * disabled after stopping it. This ensures that the video buffers queue
 281  * state can be properly initialized before buffers are accessed from the
 282  * interrupt handler.
 283  *
 284  * Enabling the video queue returns -EBUSY if the queue is already enabled.
 285  *
 286  * Disabling the video queue cancels the queue and removes all buffers from
 287  * the main queue.
 288  *
 289  * This function can't be called from interrupt context. Use
 290  * uvc_queue_cancel() instead.
 291  */
 292 int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
 293 {
 294         unsigned long flags;
 295         int ret;
 296
 297         mutex_lock(&queue->mutex);
 298         if (enable) {
 299                 ret = vb2_streamon(&queue->queue, queue->queue.type);
 300                 if (ret < 0)
 301                         goto done;
 302
 303                 queue->buf_used = 0;
 304         } else {
 305                 ret = vb2_streamoff(&queue->queue, queue->queue.type);
 306                 if (ret < 0)
 307                         goto done;
 308
 309                 spin_lock_irqsave(&queue->irqlock, flags);
 310                 INIT_LIST_HEAD(&queue->irqqueue);
 311                 spin_unlock_irqrestore(&queue->irqlock, flags);
 312         }
 313
 314 done:
 315         mutex_unlock(&queue->mutex);
 316         return ret;
 317 }
 318
 319 /*
 320  * Cancel the video buffers queue.
 321  *
 322  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 323  * wakes them up and removes them from the queue.
 324  *
 325  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 326  * fail with -ENODEV.
 327  *
 328  * This function acquires the irq spinlock and can be called from interrupt
 329  * context.
 330  */
 331 void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 332 {
 333         struct uvc_buffer *buf;
 334         unsigned long flags;
 335
 336         spin_lock_irqsave(&queue->irqlock, flags);
 337         while (!list_empty(&queue->irqqueue)) {
 338                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 339                                        queue);
 340                 list_del(&buf->queue);
 341                 buf->state = UVC_BUF_STATE_ERROR;
 342                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 343         }
 344         /* This must be protected by the irqlock spinlock to avoid race
 345          * conditions between uvc_buffer_queue and the disconnection event that
 346          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 347          * blindly replace this logic by checking for the UVC_QUEUE_DISCONNECTED
 348          * state outside the queue code.
 349          */
 350         if (disconnect)
 351                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 352         spin_unlock_irqrestore(&queue->irqlock, flags);
 353 }
 354
 355 struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
 356                 struct uvc_buffer *buf)
 357 {
 358         struct uvc_buffer *nextbuf;
 359         unsigned long flags;
 360
 361         if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) {
 362                 buf->error = 0;
 363                 buf->state = UVC_BUF_STATE_QUEUED;
 364                 buf->bytesused = 0;
 365                 vb2_set_plane_payload(&buf->buf, 0, 0);
 366                 return buf;
 367         }
 368
 369         spin_lock_irqsave(&queue->irqlock, flags);
 370         list_del(&buf->queue);
 371         if (!list_empty(&queue->irqqueue))
 372                 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 373                                            queue);
 374         else
 375                 nextbuf = NULL;
 376         spin_unlock_irqrestore(&queue->irqlock, flags);
 377
 378         buf->state = buf->error ? VB2_BUF_STATE_ERROR : UVC_BUF_STATE_DONE;
 379         vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
 380         vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
 381
 382         return nextbuf;
 383 }