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,
  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 vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
  65         struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf);
  66
  67         if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
  68             vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
  69                 uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
  70                 return -EINVAL;
  71         }
  72
  73         if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
  74                 return -ENODEV;
  75
  76         buf->state = UVC_BUF_STATE_QUEUED;
  77         buf->mem = vb2_plane_vaddr(vb, 0);
  78         buf->length = vb2_plane_size(vb, 0);
  79         if (vb->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 vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
  91         struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf);
  92         unsigned long flags;
  93
  94         spin_lock_irqsave(&queue->irqlock, flags);
  95
  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(vb, VB2_BUF_STATE_ERROR);
 104         }
 105
 106         spin_unlock_irqrestore(&queue->irqlock, flags);
 107 }
 108
 109 static struct vb2_ops uvc_queue_qops = {
 110         .queue_setup = uvc_queue_setup,
 111         .buf_prepare = uvc_buffer_prepare,
 112         .buf_queue = uvc_buffer_queue,
 113         .wait_prepare = vb2_ops_wait_prepare,
 114         .wait_finish = vb2_ops_wait_finish,
 115 };
 116
 117 int uvcg_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
 118                     struct mutex *lock)
 119 {
 120         int ret;
 121
 122         queue->queue.type = type;
 123         queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 124         queue->queue.drv_priv = queue;
 125         queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 126         queue->queue.ops = &uvc_queue_qops;
 127         queue->queue.lock = lock;
 128         queue->queue.mem_ops = &vb2_vmalloc_memops;
 129         queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
 130                                      | V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
 131         ret = vb2_queue_init(&queue->queue);
 132         if (ret)
 133                 return ret;
 134
 135         spin_lock_init(&queue->irqlock);
 136         INIT_LIST_HEAD(&queue->irqqueue);
 137         queue->flags = 0;
 138
 139         return 0;
 140 }
 141
 142 /*
 143  * Free the video buffers.
 144  */
 145 void uvcg_free_buffers(struct uvc_video_queue *queue)
 146 {
 147         vb2_queue_release(&queue->queue);
 148 }
 149
 150 /*
 151  * Allocate the video buffers.
 152  */
 153 int uvcg_alloc_buffers(struct uvc_video_queue *queue,
 154                               struct v4l2_requestbuffers *rb)
 155 {
 156         int ret;
 157
 158         ret = vb2_reqbufs(&queue->queue, rb);
 159
 160         return ret ? ret : rb->count;
 161 }
 162
 163 int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 164 {
 165         return vb2_querybuf(&queue->queue, buf);
 166 }
 167
 168 int uvcg_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
 169 {
 170         unsigned long flags;
 171         int ret;
 172
 173         ret = vb2_qbuf(&queue->queue, buf);
 174         if (ret < 0)
 175                 return ret;
 176
 177         spin_lock_irqsave(&queue->irqlock, flags);
 178         ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
 179         queue->flags &= ~UVC_QUEUE_PAUSED;
 180         spin_unlock_irqrestore(&queue->irqlock, flags);
 181         return ret;
 182 }
 183
 184 /*
 185  * Dequeue a video buffer. If nonblocking is false, block until a buffer is
 186  * available.
 187  */
 188 int uvcg_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
 189                         int nonblocking)
 190 {
 191         return vb2_dqbuf(&queue->queue, buf, nonblocking);
 192 }
 193
 194 /*
 195  * Poll the video queue.
 196  *
 197  * This function implements video queue polling and is intended to be used by
 198  * the device poll handler.
 199  */
 200 unsigned int uvcg_queue_poll(struct uvc_video_queue *queue, struct file *file,
 201                              poll_table *wait)
 202 {
 203         return vb2_poll(&queue->queue, file, wait);
 204 }
 205
 206 int uvcg_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
 207 {
 208         return vb2_mmap(&queue->queue, vma);
 209 }
 210
 211 #ifndef CONFIG_MMU
 212 /*
 213  * Get unmapped area.
 214  *
 215  * NO-MMU arch need this function to make mmap() work correctly.
 216  */
 217 unsigned long uvcg_queue_get_unmapped_area(struct uvc_video_queue *queue,
 218                                            unsigned long pgoff)
 219 {
 220         return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
 221 }
 222 #endif
 223
 224 /*
 225  * Cancel the video buffers queue.
 226  *
 227  * Cancelling the queue marks all buffers on the irq queue as erroneous,
 228  * wakes them up and removes them from the queue.
 229  *
 230  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
 231  * fail with -ENODEV.
 232  *
 233  * This function acquires the irq spinlock and can be called from interrupt
 234  * context.
 235  */
 236 void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
 237 {
 238         struct uvc_buffer *buf;
 239         unsigned long flags;
 240
 241         spin_lock_irqsave(&queue->irqlock, flags);
 242         while (!list_empty(&queue->irqqueue)) {
 243                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 244                                        queue);
 245                 list_del(&buf->queue);
 246                 buf->state = UVC_BUF_STATE_ERROR;
 247                 vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
 248         }
 249         /* This must be protected by the irqlock spinlock to avoid race
 250          * conditions between uvc_queue_buffer and the disconnection event that
 251          * could result in an interruptible wait in uvc_dequeue_buffer. Do not
 252          * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
 253          * state outside the queue code.
 254          */
 255         if (disconnect)
 256                 queue->flags |= UVC_QUEUE_DISCONNECTED;
 257         spin_unlock_irqrestore(&queue->irqlock, flags);
 258 }
 259
 260 /*
 261  * Enable or disable the video buffers queue.
 262  *
 263  * The queue must be enabled before starting video acquisition and must be
 264  * disabled after stopping it. This ensures that the video buffers queue
 265  * state can be properly initialized before buffers are accessed from the
 266  * interrupt handler.
 267  *
 268  * Enabling the video queue initializes parameters (such as sequence number,
 269  * sync pattern, ...). If the queue is already enabled, return -EBUSY.
 270  *
 271  * Disabling the video queue cancels the queue and removes all buffers from
 272  * the main queue.
 273  *
 274  * This function can't be called from interrupt context. Use
 275  * uvcg_queue_cancel() instead.
 276  */
 277 int uvcg_queue_enable(struct uvc_video_queue *queue, int enable)
 278 {
 279         unsigned long flags;
 280         int ret = 0;
 281
 282         if (enable) {
 283                 ret = vb2_streamon(&queue->queue, queue->queue.type);
 284                 if (ret < 0)
 285                         return ret;
 286
 287                 queue->sequence = 0;
 288                 queue->buf_used = 0;
 289         } else {
 290                 ret = vb2_streamoff(&queue->queue, queue->queue.type);
 291                 if (ret < 0)
 292                         return ret;
 293
 294                 spin_lock_irqsave(&queue->irqlock, flags);
 295                 INIT_LIST_HEAD(&queue->irqqueue);
 296
 297                 /*
 298                  * FIXME: We need to clear the DISCONNECTED flag to ensure that
 299                  * applications will be able to queue buffers for the next
 300                  * streaming run. However, clearing it here doesn't guarantee
 301                  * that the device will be reconnected in the meantime.
 302                  */
 303                 queue->flags &= ~UVC_QUEUE_DISCONNECTED;
 304                 spin_unlock_irqrestore(&queue->irqlock, flags);
 305         }
 306
 307         return ret;
 308 }
 309
 310 /* called with &queue_irqlock held.. */
 311 struct uvc_buffer *uvcg_queue_next_buffer(struct uvc_video_queue *queue,
 312                                           struct uvc_buffer *buf)
 313 {
 314         struct uvc_buffer *nextbuf;
 315
 316         if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
 317              buf->length != buf->bytesused) {
 318                 buf->state = UVC_BUF_STATE_QUEUED;
 319                 vb2_set_plane_payload(&buf->buf.vb2_buf, 0, 0);
 320                 return buf;
 321         }
 322
 323         list_del(&buf->queue);
 324         if (!list_empty(&queue->irqqueue))
 325                 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 326                                            queue);
 327         else
 328                 nextbuf = NULL;
 329
 330         buf->buf.field = V4L2_FIELD_NONE;
 331         buf->buf.sequence = queue->sequence++;
 332         buf->buf.vb2_buf.timestamp = ktime_get_ns();
 333
 334         vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused);
 335         vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_DONE);
 336
 337         return nextbuf;
 338 }
 339
 340 struct uvc_buffer *uvcg_queue_head(struct uvc_video_queue *queue)
 341 {
 342         struct uvc_buffer *buf = NULL;
 343
 344         if (!list_empty(&queue->irqqueue))
 345                 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
 346                                        queue);
 347         else
 348                 queue->flags |= UVC_QUEUE_PAUSED;
 349
 350         return buf;
 351 }
 352