drivers/usb/gadget/function/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/v4l2-common.h>
  24 #include <media/videobuf2-vmalloc.h>
  25
  26 #include "uvc.h"
  27
  28 /* ------------------------------------------------------------------------
  29  * Video buffers queue management.
  30  *
  31  * Video queues is initialized by uvcg_queue_init(). The function performs
  32  * basic initialization of the uvc_video_queue struct and never fails.
  33  *
  34  * Video buffers are managed by videobuf2. The driver uses a mutex to protect
  35  * the videobuf2 queue operations by serializing calls to videobuf2 and a
  36  * spinlock to protect the IRQ queue that holds the buffers to be processed by
  37  * the driver.
  38  */
  39
  40 /* -----------------------------------------------------------------------------
  41  * videobuf2 queue operations
  42  */
  43
  44 static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
  45                            unsigned int *nbuffers, unsigned int *nplanes,
  46                            unsigned int sizes[], void *alloc_ctxs[])
  47 {
  48         struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
  49         struct uvc_video *video = container_of(queue, struct uvc_video, queue);
  50
  51         if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
  52                 *nbuffers = UVC_MAX_VIDEO_BUFFERS;
  53
  54         *nplanes = 1;
  55
  56         sizes[0] = video->imagesize;
  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->mem = vb2_plane_vaddr(vb, 0);
  77         buf->length = vb2_plane_size(vb, 0);
  78         if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  79                 buf->bytesused = 0;
  80         else
  81                 buf->bytesused = vb2_get_plane_payload(vb, 0);
  82
  83         return 0;
  84 }
  85
  86 static void uvc_buffer_queue(struct vb2_buffer *vb)
  87 {
  88         struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  89         struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  90         unsigned long flags;
  91
  92         spin_lock_irqsave(&queue->irqlock, flags);
  93
  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 struct vb2_ops uvc_queue_qops = {
 108         .queue_setup = uvc_queue_setup,
 109         .buf_prepare = uvc_buffer_prepare,
 110         .buf_queue = uvc_buffer_queue,
 111         .wait_prepare = vb2_ops_wait_prepare,
 112         .wait_finish = vb2_ops_wait_finish,
 113 };
 114
 115 int uvcg_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
 116                     struct mutex *lock)
 117 {
 118         int ret;
 119
 120         queue->queue.type = type;
 121         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 122         queue->queue.drv_priv = queue;
 123         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 124         queue->queue.ops = &uvc_queue_qops;
 125         queue->queue.lock = lock;
 126         queue->queue.mem_ops = &vb2_vmalloc_memops;
 127         queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
 128                                      | V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
 129         ret = vb2_queue_init(&queue->queue);
 130         if (ret)
 131                 return ret;
 132
 133         spin_lock_init(&queue->irqlock);
 134         INIT_LIST_HEAD(&queue->irqqueue);
 135         queue->flags = 0;
 136
 137         return 0;
 138 }
 139
 140 /*
 141  * Free the video buffers.
 142  */
 143 void uvcg_free_buffers(struct uvc_video_queue *queue)
 144 {
 145         vb2_queue_release(&queue->queue);
 146 }
 147
 148 /*
 149  * Allocate the video buffers.
 150  */
 151 int uvcg_alloc_buffers(struct uvc_video_queue *queue,
 152                               struct v4l2_requestbuffers *rb)
 153 {
 154         int ret;
 155
 156         ret = vb2_reqbufs(&queue->queue, rb);
 157
 158         return ret ? ret : rb->count;
 159 }
 160
 161 int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 162 {
 163         return vb2_querybuf(&queue->queue, buf);
 164 }
 165
 166 int uvcg_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 167 {
 168         unsigned long flags;
 169         int ret;
 170
 171         ret = vb2_qbuf(&queue->queue, buf);
 172         if (ret < 0)
 173                 return ret;
 174
 175         spin_lock_irqsave(&queue->irqlock, flags);
 176         ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
 177         queue->flags &= ~UVC_QUEUE_PAUSED;
 178         spin_unlock_irqrestore(&queue->irqlock, flags);
 179         return ret;
 180 }
 181
 182 /*
 183  * Dequeue a video buffer. If nonblocking is false, block until a buffer is
 184  * available.
 185  */
 186 int uvcg_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
 187                         int nonblocking)
 188 {
 189         return vb2_dqbuf(&queue->queue, buf, nonblocking);
 190 }
 191
 192 /*
 193  * Poll the video queue.
 194  *
 195  * This function implements video queue polling and is intended to be used by
 196  * the device poll handler.
 197  */
 198 unsigned int uvcg_queue_poll(struct uvc_video_queue *queue, struct file *file,
 199                              poll_table *wait)
 200 {
 201         return vb2_poll(&queue->queue, file, wait);
 202 }
 203
 204 int uvcg_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
 205 {
 206         return vb2_mmap(&queue->queue, vma);
 207 }
 208
 209 #ifndef CONFIG_MMU
 210 /*
 211  * Get unmapped area.
 212  *
 213  * NO-MMU arch need this function to make mmap() work correctly.
 214  */
 215 unsigned long uvcg_queue_get_unmapped_area(struct uvc_video_queue *queue,
 216                                            unsigned long pgoff)
 217 {
 218         return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 219 }
 220 #endif
 221
 222 /*
 223  * Cancel the video buffers queue.
 224  *
 225  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 226  * wakes them up and removes them from the queue.
 227  *
 228  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 229  * fail with -ENODEV.
 230  *
 231  * This function acquires the irq spinlock and can be called from interrupt
 232  * context.
 233  */
 234 void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 235 {
 236         struct uvc_buffer *buf;
 237         unsigned long flags;
 238
 239         spin_lock_irqsave(&queue->irqlock, flags);
 240         while (!list_empty(&queue->irqqueue)) {
 241                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 242                                        queue);
 243                 list_del(&buf->queue);
 244                 buf->state = UVC_BUF_STATE_ERROR;
 245                 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
 246         }
 247         /* This must be protected by the irqlock spinlock to avoid race
 248          * conditions between uvc_queue_buffer and the disconnection event that
 249          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 250          * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
 251          * state outside the queue code.
 252          */
 253         if (disconnect)
 254                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 255         spin_unlock_irqrestore(&queue->irqlock, flags);
 256 }
 257
 258 /*
 259  * Enable or disable the video buffers queue.
 260  *
 261  * The queue must be enabled before starting video acquisition and must be
 262  * disabled after stopping it. This ensures that the video buffers queue
 263  * state can be properly initialized before buffers are accessed from the
 264  * interrupt handler.
 265  *
 266  * Enabling the video queue initializes parameters (such as sequence number,
 267  * sync pattern, ...). If the queue is already enabled, return -EBUSY.
 268  *
 269  * Disabling the video queue cancels the queue and removes all buffers from
 270  * the main queue.
 271  *
 272  * This function can't be called from interrupt context. Use
 273  * uvcg_queue_cancel() instead.
 274  */
 275 int uvcg_queue_enable(struct uvc_video_queue *queue, int enable)
 276 {
 277         unsigned long flags;
 278         int ret = 0;
 279
 280         if (enable) {
 281                 ret = vb2_streamon(&queue->queue, queue->queue.type);
 282                 if (ret < 0)
 283                         return ret;
 284
 285                 queue->sequence = 0;
 286                 queue->buf_used = 0;
 287         } else {
 288                 ret = vb2_streamoff(&queue->queue, queue->queue.type);
 289                 if (ret < 0)
 290                         return ret;
 291
 292                 spin_lock_irqsave(&queue->irqlock, flags);
 293                 INIT_LIST_HEAD(&queue->irqqueue);
 294
 295                 /*
 296                  * FIXME: We need to clear the DISCONNECTED flag to ensure that
 297                  * applications will be able to queue buffers for the next
 298                  * streaming run. However, clearing it here doesn't guarantee
 299                  * that the device will be reconnected in the meantime.
 300                  */
 301                 queue->flags &= ~UVC_QUEUE_DISCONNECTED;
 302                 spin_unlock_irqrestore(&queue->irqlock, flags);
 303         }
 304
 305         return ret;
 306 }
 307
 308 /* called with &queue_irqlock held.. */
 309 struct uvc_buffer *uvcg_queue_next_buffer(struct uvc_video_queue *queue,
 310                                           struct uvc_buffer *buf)
 311 {
 312         struct uvc_buffer *nextbuf;
 313
 314         if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
 315              buf->length != buf->bytesused) {
 316                 buf->state = UVC_BUF_STATE_QUEUED;
 317                 vb2_set_plane_payload(&buf->buf, 0, 0);
 318                 return buf;
 319         }
 320
 321         list_del(&buf->queue);
 322         if (!list_empty(&queue->irqqueue))
 323                 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 324                                            queue);
 325         else
 326                 nextbuf = NULL;
 327
 328         buf->buf.v4l2_buf.field = V4L2_FIELD_NONE;
 329         buf->buf.v4l2_buf.sequence = queue->sequence++;
 330         v4l2_get_timestamp(&buf->buf.v4l2_buf.timestamp);
 331
 332         vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
 333         vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
 334
 335         return nextbuf;
 336 }
 337
 338 struct uvc_buffer *uvcg_queue_head(struct uvc_video_queue *queue)
 339 {
 340         struct uvc_buffer *buf = NULL;
 341
 342         if (!list_empty(&queue->irqqueue))
 343                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 344                                        queue);
 345         else
 346                 queue->flags |= UVC_QUEUE_PAUSED;
 347
 348         return buf;
 349 }
 350