drivers/usb/gadget/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 #include <linux/atomic.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mm.h>
  16 #include <linux/list.h>
  17 #include <linux/module.h>
  18 #include <linux/usb.h>
  19 #include <linux/videodev2.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/wait.h>
  22
  23 #include <media/videobuf2-vmalloc.h>
  24
  25 #include "uvc.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_video *video = container_of(queue, struct uvc_video, queue);
  49
  50         if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
  51                 *nbuffers = UVC_MAX_VIDEO_BUFFERS;
  52
  53         *nplanes = 1;
  54
  55         sizes[0] = video->imagesize;
  56
  57         return 0;
  58 }
  59
  60 static int uvc_buffer_prepare(struct vb2_buffer *vb)
  61 {
  62         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  63         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  64
  65         if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
  66             vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
  67                 uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
  68                 return -EINVAL;
  69         }
  70
  71         if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
  72                 return -ENODEV;
  73
  74         buf->state = UVC_BUF_STATE_QUEUED;
  75         buf->mem = vb2_plane_vaddr(vb, 0);
  76         buf->length = vb2_plane_size(vb, 0);
  77         if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  78                 buf->bytesused = 0;
  79         else
  80                 buf->bytesused = vb2_get_plane_payload(vb, 0);
  81
  82         return 0;
  83 }
  84
  85 static void uvc_buffer_queue(struct vb2_buffer *vb)
  86 {
  87         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  88         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  89         unsigned long flags;
  90
  91         spin_lock_irqsave(&queue->irqlock, flags);
  92
  93         if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
  94                 list_add_tail(&buf->queue, &queue->irqqueue);
  95         } else {
  96                 /* If the device is disconnected return the buffer to userspace
  97                  * directly. The next QBUF call will fail with -ENODEV.
  98                  */
  99                 buf->state = UVC_BUF_STATE_ERROR;
 100                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 101         }
 102
 103         spin_unlock_irqrestore(&queue->irqlock, flags);
 104 }
 105
 106 static struct vb2_ops uvc_queue_qops = {
 107         .queue_setup = uvc_queue_setup,
 108         .buf_prepare = uvc_buffer_prepare,
 109         .buf_queue = uvc_buffer_queue,
 110 };
 111
 112 static int uvc_queue_init(struct uvc_video_queue *queue,
 113                           enum v4l2_buf_type type)
 114 {
 115         int ret;
 116
 117         queue->queue.type = type;
 118         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
 119         queue->queue.drv_priv = queue;
 120         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 121         queue->queue.ops = &uvc_queue_qops;
 122         queue->queue.mem_ops = &vb2_vmalloc_memops;
 123         ret = vb2_queue_init(&queue->queue);
 124         if (ret)
 125                 return ret;
 126
 127         mutex_init(&queue->mutex);
 128         spin_lock_init(&queue->irqlock);
 129         INIT_LIST_HEAD(&queue->irqqueue);
 130         queue->flags = 0;
 131
 132         return 0;
 133 }
 134
 135 /*
 136  * Free the video buffers.
 137  */
 138 static void uvc_free_buffers(struct uvc_video_queue *queue)
 139 {
 140         mutex_lock(&queue->mutex);
 141         vb2_queue_release(&queue->queue);
 142         mutex_unlock(&queue->mutex);
 143 }
 144
 145 /*
 146  * Allocate the video buffers.
 147  */
 148 static int uvc_alloc_buffers(struct uvc_video_queue *queue,
 149                              struct v4l2_requestbuffers *rb)
 150 {
 151         int ret;
 152
 153         mutex_lock(&queue->mutex);
 154         ret = vb2_reqbufs(&queue->queue, rb);
 155         mutex_unlock(&queue->mutex);
 156
 157         return ret ? ret : rb->count;
 158 }
 159
 160 static int uvc_query_buffer(struct uvc_video_queue *queue,
 161                             struct v4l2_buffer *buf)
 162 {
 163         int ret;
 164
 165         mutex_lock(&queue->mutex);
 166         ret = vb2_querybuf(&queue->queue, buf);
 167         mutex_unlock(&queue->mutex);
 168
 169         return ret;
 170 }
 171
 172 static int uvc_queue_buffer(struct uvc_video_queue *queue,
 173                             struct v4l2_buffer *buf)
 174 {
 175         unsigned long flags;
 176         int ret;
 177
 178         mutex_lock(&queue->mutex);
 179         ret = vb2_qbuf(&queue->queue, buf);
 180         if (ret < 0)
 181                 goto done;
 182
 183         spin_lock_irqsave(&queue->irqlock, flags);
 184         ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
 185         queue->flags &= ~UVC_QUEUE_PAUSED;
 186         spin_unlock_irqrestore(&queue->irqlock, flags);
 187
 188 done:
 189         mutex_unlock(&queue->mutex);
 190         return ret;
 191 }
 192
 193 /*
 194  * Dequeue a video buffer. If nonblocking is false, block until a buffer is
 195  * available.
 196  */
 197 static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
 198                               struct v4l2_buffer *buf, int nonblocking)
 199 {
 200         int ret;
 201
 202         mutex_lock(&queue->mutex);
 203         ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
 204         mutex_unlock(&queue->mutex);
 205
 206         return ret;
 207 }
 208
 209 /*
 210  * Poll the video queue.
 211  *
 212  * This function implements video queue polling and is intended to be used by
 213  * the device poll handler.
 214  */
 215 static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
 216                                    struct file *file, poll_table *wait)
 217 {
 218         unsigned int ret;
 219
 220         mutex_lock(&queue->mutex);
 221         ret = vb2_poll(&queue->queue, file, wait);
 222         mutex_unlock(&queue->mutex);
 223
 224         return ret;
 225 }
 226
 227 static int uvc_queue_mmap(struct uvc_video_queue *queue,
 228                           struct vm_area_struct *vma)
 229 {
 230         int ret;
 231
 232         mutex_lock(&queue->mutex);
 233         ret = vb2_mmap(&queue->queue, vma);
 234         mutex_unlock(&queue->mutex);
 235
 236         return ret;
 237 }
 238
 239 #ifndef CONFIG_MMU
 240 /*
 241  * Get unmapped area.
 242  *
 243  * NO-MMU arch need this function to make mmap() work correctly.
 244  */
 245 static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
 246                 unsigned long pgoff)
 247 {
 248         unsigned long ret;
 249
 250         mutex_lock(&queue->mutex);
 251         ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 252         mutex_unlock(&queue->mutex);
 253         return ret;
 254 }
 255 #endif
 256
 257 /*
 258  * Cancel the video buffers queue.
 259  *
 260  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 261  * wakes them up and removes them from the queue.
 262  *
 263  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 264  * fail with -ENODEV.
 265  *
 266  * This function acquires the irq spinlock and can be called from interrupt
 267  * context.
 268  */
 269 static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 270 {
 271         struct uvc_buffer *buf;
 272         unsigned long flags;
 273
 274         spin_lock_irqsave(&queue->irqlock, flags);
 275         while (!list_empty(&queue->irqqueue)) {
 276                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 277                                        queue);
 278                 list_del(&buf->queue);
 279                 buf->state = UVC_BUF_STATE_ERROR;
 280                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 281         }
 282         /* This must be protected by the irqlock spinlock to avoid race
 283          * conditions between uvc_queue_buffer and the disconnection event that
 284          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 285          * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
 286          * state outside the queue code.
 287          */
 288         if (disconnect)
 289                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 290         spin_unlock_irqrestore(&queue->irqlock, flags);
 291 }
 292
 293 /*
 294  * Enable or disable the video buffers queue.
 295  *
 296  * The queue must be enabled before starting video acquisition and must be
 297  * disabled after stopping it. This ensures that the video buffers queue
 298  * state can be properly initialized before buffers are accessed from the
 299  * interrupt handler.
 300  *
 301  * Enabling the video queue initializes parameters (such as sequence number,
 302  * sync pattern, ...). If the queue is already enabled, return -EBUSY.
 303  *
 304  * Disabling the video queue cancels the queue and removes all buffers from
 305  * the main queue.
 306  *
 307  * This function can't be called from interrupt context. Use
 308  * uvc_queue_cancel() instead.
 309  */
 310 static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
 311 {
 312         unsigned long flags;
 313         int ret = 0;
 314
 315         mutex_lock(&queue->mutex);
 316         if (enable) {
 317                 ret = vb2_streamon(&queue->queue, queue->queue.type);
 318                 if (ret < 0)
 319                         goto done;
 320
 321                 queue->sequence = 0;
 322                 queue->buf_used = 0;
 323         } else {
 324                 ret = vb2_streamoff(&queue->queue, queue->queue.type);
 325                 if (ret < 0)
 326                         goto done;
 327
 328                 spin_lock_irqsave(&queue->irqlock, flags);
 329                 INIT_LIST_HEAD(&queue->irqqueue);
 330
 331                 /*
 332                  * FIXME: We need to clear the DISCONNECTED flag to ensure that
 333                  * applications will be able to queue buffers for the next
 334                  * streaming run. However, clearing it here doesn't guarantee
 335                  * that the device will be reconnected in the meantime.
 336                  */
 337                 queue->flags &= ~UVC_QUEUE_DISCONNECTED;
 338                 spin_unlock_irqrestore(&queue->irqlock, flags);
 339         }
 340
 341 done:
 342         mutex_unlock(&queue->mutex);
 343         return ret;
 344 }
 345
 346 /* called with &queue_irqlock held.. */
 347 static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
 348                                                 struct uvc_buffer *buf)
 349 {
 350         struct uvc_buffer *nextbuf;
 351
 352         if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
 353              buf->length != buf->bytesused) {
 354                 buf->state = UVC_BUF_STATE_QUEUED;
 355                 vb2_set_plane_payload(&buf->buf, 0, 0);
 356                 return buf;
 357         }
 358
 359         list_del(&buf->queue);
 360         if (!list_empty(&queue->irqqueue))
 361                 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 362                                            queue);
 363         else
 364                 nextbuf = NULL;
 365
 366         /*
 367          * FIXME: with videobuf2, the sequence number or timestamp fields
 368          * are valid only for video capture devices and the UVC gadget usually
 369          * is a video output device. Keeping these until the specs are clear on
 370          * this aspect.
 371          */
 372         buf->buf.v4l2_buf.sequence = queue->sequence++;
 373         do_gettimeofday(&buf->buf.v4l2_buf.timestamp);
 374
 375         vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
 376         vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
 377
 378         return nextbuf;
 379 }
 380
 381 static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue)
 382 {
 383         struct uvc_buffer *buf = NULL;
 384
 385         if (!list_empty(&queue->irqqueue))
 386                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 387                                        queue);
 388         else
 389                 queue->flags |= UVC_QUEUE_PAUSED;
 390
 391         return buf;
 392 }
 393