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 void uvc_wait_prepare(struct vb2_queue *vq)
 107 {
 108         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 109
 110         mutex_unlock(&queue->mutex);
 111 }
 112
 113 static void uvc_wait_finish(struct vb2_queue *vq)
 114 {
 115         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
 116
 117         mutex_lock(&queue->mutex);
 118 }
 119
 120 static struct vb2_ops uvc_queue_qops = {
 121         .queue_setup = uvc_queue_setup,
 122         .buf_prepare = uvc_buffer_prepare,
 123         .buf_queue = uvc_buffer_queue,
 124         .wait_prepare = uvc_wait_prepare,
 125         .wait_finish = uvc_wait_finish,
 126 };
 127
 128 static int uvc_queue_init(struct uvc_video_queue *queue,
 129                           enum v4l2_buf_type type)
 130 {
 131         int ret;
 132
 133         queue->queue.type = type;
 134         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
 135         queue->queue.drv_priv = queue;
 136         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 137         queue->queue.ops = &uvc_queue_qops;
 138         queue->queue.mem_ops = &vb2_vmalloc_memops;
 139         ret = vb2_queue_init(&queue->queue);
 140         if (ret)
 141                 return ret;
 142
 143         mutex_init(&queue->mutex);
 144         spin_lock_init(&queue->irqlock);
 145         INIT_LIST_HEAD(&queue->irqqueue);
 146         queue->flags = 0;
 147
 148         return 0;
 149 }
 150
 151 /*
 152  * Free the video buffers.
 153  */
 154 static void uvc_free_buffers(struct uvc_video_queue *queue)
 155 {
 156         mutex_lock(&queue->mutex);
 157         vb2_queue_release(&queue->queue);
 158         mutex_unlock(&queue->mutex);
 159 }
 160
 161 /*
 162  * Allocate the video buffers.
 163  */
 164 static int uvc_alloc_buffers(struct uvc_video_queue *queue,
 165                              struct v4l2_requestbuffers *rb)
 166 {
 167         int ret;
 168
 169         mutex_lock(&queue->mutex);
 170         ret = vb2_reqbufs(&queue->queue, rb);
 171         mutex_unlock(&queue->mutex);
 172
 173         return ret ? ret : rb->count;
 174 }
 175
 176 static int uvc_query_buffer(struct uvc_video_queue *queue,
 177                             struct v4l2_buffer *buf)
 178 {
 179         int ret;
 180
 181         mutex_lock(&queue->mutex);
 182         ret = vb2_querybuf(&queue->queue, buf);
 183         mutex_unlock(&queue->mutex);
 184
 185         return ret;
 186 }
 187
 188 static int uvc_queue_buffer(struct uvc_video_queue *queue,
 189                             struct v4l2_buffer *buf)
 190 {
 191         unsigned long flags;
 192         int ret;
 193
 194         mutex_lock(&queue->mutex);
 195         ret = vb2_qbuf(&queue->queue, buf);
 196         if (ret < 0)
 197                 goto done;
 198
 199         spin_lock_irqsave(&queue->irqlock, flags);
 200         ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
 201         queue->flags &= ~UVC_QUEUE_PAUSED;
 202         spin_unlock_irqrestore(&queue->irqlock, flags);
 203
 204 done:
 205         mutex_unlock(&queue->mutex);
 206         return ret;
 207 }
 208
 209 /*
 210  * Dequeue a video buffer. If nonblocking is false, block until a buffer is
 211  * available.
 212  */
 213 static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
 214                               struct v4l2_buffer *buf, int nonblocking)
 215 {
 216         int ret;
 217
 218         mutex_lock(&queue->mutex);
 219         ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
 220         mutex_unlock(&queue->mutex);
 221
 222         return ret;
 223 }
 224
 225 /*
 226  * Poll the video queue.
 227  *
 228  * This function implements video queue polling and is intended to be used by
 229  * the device poll handler.
 230  */
 231 static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
 232                                    struct file *file, poll_table *wait)
 233 {
 234         unsigned int ret;
 235
 236         mutex_lock(&queue->mutex);
 237         ret = vb2_poll(&queue->queue, file, wait);
 238         mutex_unlock(&queue->mutex);
 239
 240         return ret;
 241 }
 242
 243 static int uvc_queue_mmap(struct uvc_video_queue *queue,
 244                           struct vm_area_struct *vma)
 245 {
 246         int ret;
 247
 248         mutex_lock(&queue->mutex);
 249         ret = vb2_mmap(&queue->queue, vma);
 250         mutex_unlock(&queue->mutex);
 251
 252         return ret;
 253 }
 254
 255 #ifndef CONFIG_MMU
 256 /*
 257  * Get unmapped area.
 258  *
 259  * NO-MMU arch need this function to make mmap() work correctly.
 260  */
 261 static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
 262                 unsigned long pgoff)
 263 {
 264         unsigned long ret;
 265
 266         mutex_lock(&queue->mutex);
 267         ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 268         mutex_unlock(&queue->mutex);
 269         return ret;
 270 }
 271 #endif
 272
 273 /*
 274  * Cancel the video buffers queue.
 275  *
 276  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 277  * wakes them up and removes them from the queue.
 278  *
 279  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 280  * fail with -ENODEV.
 281  *
 282  * This function acquires the irq spinlock and can be called from interrupt
 283  * context.
 284  */
 285 static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 286 {
 287         struct uvc_buffer *buf;
 288         unsigned long flags;
 289
 290         spin_lock_irqsave(&queue->irqlock, flags);
 291         while (!list_empty(&queue->irqqueue)) {
 292                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 293                                        queue);
 294                 list_del(&buf->queue);
 295                 buf->state = UVC_BUF_STATE_ERROR;
 296                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 297         }
 298         /* This must be protected by the irqlock spinlock to avoid race
 299          * conditions between uvc_queue_buffer and the disconnection event that
 300          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 301          * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
 302          * state outside the queue code.
 303          */
 304         if (disconnect)
 305                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 306         spin_unlock_irqrestore(&queue->irqlock, flags);
 307 }
 308
 309 /*
 310  * Enable or disable the video buffers queue.
 311  *
 312  * The queue must be enabled before starting video acquisition and must be
 313  * disabled after stopping it. This ensures that the video buffers queue
 314  * state can be properly initialized before buffers are accessed from the
 315  * interrupt handler.
 316  *
 317  * Enabling the video queue initializes parameters (such as sequence number,
 318  * sync pattern, ...). If the queue is already enabled, return -EBUSY.
 319  *
 320  * Disabling the video queue cancels the queue and removes all buffers from
 321  * the main queue.
 322  *
 323  * This function can't be called from interrupt context. Use
 324  * uvc_queue_cancel() instead.
 325  */
 326 static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
 327 {
 328         unsigned long flags;
 329         int ret = 0;
 330
 331         mutex_lock(&queue->mutex);
 332         if (enable) {
 333                 ret = vb2_streamon(&queue->queue, queue->queue.type);
 334                 if (ret < 0)
 335                         goto done;
 336
 337                 queue->sequence = 0;
 338                 queue->buf_used = 0;
 339         } else {
 340                 ret = vb2_streamoff(&queue->queue, queue->queue.type);
 341                 if (ret < 0)
 342                         goto done;
 343
 344                 spin_lock_irqsave(&queue->irqlock, flags);
 345                 INIT_LIST_HEAD(&queue->irqqueue);
 346
 347                 /*
 348                  * FIXME: We need to clear the DISCONNECTED flag to ensure that
 349                  * applications will be able to queue buffers for the next
 350                  * streaming run. However, clearing it here doesn't guarantee
 351                  * that the device will be reconnected in the meantime.
 352                  */
 353                 queue->flags &= ~UVC_QUEUE_DISCONNECTED;
 354                 spin_unlock_irqrestore(&queue->irqlock, flags);
 355         }
 356
 357 done:
 358         mutex_unlock(&queue->mutex);
 359         return ret;
 360 }
 361
 362 /* called with &queue_irqlock held.. */
 363 static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
 364                                                 struct uvc_buffer *buf)
 365 {
 366         struct uvc_buffer *nextbuf;
 367
 368         if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
 369              buf->length != buf->bytesused) {
 370                 buf->state = UVC_BUF_STATE_QUEUED;
 371                 vb2_set_plane_payload(&buf->buf, 0, 0);
 372                 return buf;
 373         }
 374
 375         list_del(&buf->queue);
 376         if (!list_empty(&queue->irqqueue))
 377                 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 378                                            queue);
 379         else
 380                 nextbuf = NULL;
 381
 382         /*
 383          * FIXME: with videobuf2, the sequence number or timestamp fields
 384          * are valid only for video capture devices and the UVC gadget usually
 385          * is a video output device. Keeping these until the specs are clear on
 386          * this aspect.
 387          */
 388         buf->buf.v4l2_buf.sequence = queue->sequence++;
 389         do_gettimeofday(&buf->buf.v4l2_buf.timestamp);
 390
 391         vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
 392         vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
 393
 394         return nextbuf;
 395 }
 396
 397 static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue)
 398 {
 399         struct uvc_buffer *buf = NULL;
 400
 401         if (!list_empty(&queue->irqqueue))
 402                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 403                                        queue);
 404         else
 405                 queue->flags |= UVC_QUEUE_PAUSED;
 406
 407         return buf;
 408 }
 409