uvc_queue.c 10 KB

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  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. #include <linux/atomic.h>
  13. #include <linux/kernel.h>
  14. #include <linux/mm.h>
  15. #include <linux/list.h>
  16. #include <linux/module.h>
  17. #include <linux/usb.h>
  18. #include <linux/videodev2.h>
  19. #include <linux/vmalloc.h>
  20. #include <linux/wait.h>
  21. #include <media/videobuf2-vmalloc.h>
  22. #include "uvc.h"
  23. /* ------------------------------------------------------------------------
  24. * Video buffers queue management.
  25. *
  26. * Video queues is initialized by uvc_queue_init(). The function performs
  27. * basic initialization of the uvc_video_queue struct and never fails.
  28. *
  29. * Video buffers are managed by videobuf2. The driver uses a mutex to protect
  30. * the videobuf2 queue operations by serializing calls to videobuf2 and a
  31. * spinlock to protect the IRQ queue that holds the buffers to be processed by
  32. * the driver.
  33. */
  34. /* -----------------------------------------------------------------------------
  35. * videobuf2 queue operations
  36. */
  37. static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
  38. unsigned int *nbuffers, unsigned int *nplanes,
  39. unsigned int sizes[], void *alloc_ctxs[])
  40. {
  41. struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
  42. struct uvc_video *video = container_of(queue, struct uvc_video, queue);
  43. if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
  44. *nbuffers = UVC_MAX_VIDEO_BUFFERS;
  45. *nplanes = 1;
  46. sizes[0] = video->imagesize;
  47. return 0;
  48. }
  49. static int uvc_buffer_prepare(struct vb2_buffer *vb)
  50. {
  51. struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  52. struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  53. if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
  54. vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
  55. uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
  56. return -EINVAL;
  57. }
  58. if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
  59. return -ENODEV;
  60. buf->state = UVC_BUF_STATE_QUEUED;
  61. buf->mem = vb2_plane_vaddr(vb, 0);
  62. buf->length = vb2_plane_size(vb, 0);
  63. if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  64. buf->bytesused = 0;
  65. else
  66. buf->bytesused = vb2_get_plane_payload(vb, 0);
  67. return 0;
  68. }
  69. static void uvc_buffer_queue(struct vb2_buffer *vb)
  70. {
  71. struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
  72. struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
  73. unsigned long flags;
  74. spin_lock_irqsave(&queue->irqlock, flags);
  75. if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
  76. list_add_tail(&buf->queue, &queue->irqqueue);
  77. } else {
  78. /* If the device is disconnected return the buffer to userspace
  79. * directly. The next QBUF call will fail with -ENODEV.
  80. */
  81. buf->state = UVC_BUF_STATE_ERROR;
  82. vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
  83. }
  84. spin_unlock_irqrestore(&queue->irqlock, flags);
  85. }
  86. static void uvc_wait_prepare(struct vb2_queue *vq)
  87. {
  88. struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
  89. mutex_unlock(&queue->mutex);
  90. }
  91. static void uvc_wait_finish(struct vb2_queue *vq)
  92. {
  93. struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
  94. mutex_lock(&queue->mutex);
  95. }
  96. static struct vb2_ops uvc_queue_qops = {
  97. .queue_setup = uvc_queue_setup,
  98. .buf_prepare = uvc_buffer_prepare,
  99. .buf_queue = uvc_buffer_queue,
  100. .wait_prepare = uvc_wait_prepare,
  101. .wait_finish = uvc_wait_finish,
  102. };
  103. static int uvc_queue_init(struct uvc_video_queue *queue,
  104. enum v4l2_buf_type type)
  105. {
  106. int ret;
  107. queue->queue.type = type;
  108. queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
  109. queue->queue.drv_priv = queue;
  110. queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
  111. queue->queue.ops = &uvc_queue_qops;
  112. queue->queue.mem_ops = &vb2_vmalloc_memops;
  113. ret = vb2_queue_init(&queue->queue);
  114. if (ret)
  115. return ret;
  116. mutex_init(&queue->mutex);
  117. spin_lock_init(&queue->irqlock);
  118. INIT_LIST_HEAD(&queue->irqqueue);
  119. queue->flags = 0;
  120. return 0;
  121. }
  122. /*
  123. * Free the video buffers.
  124. */
  125. static void uvc_free_buffers(struct uvc_video_queue *queue)
  126. {
  127. mutex_lock(&queue->mutex);
  128. vb2_queue_release(&queue->queue);
  129. mutex_unlock(&queue->mutex);
  130. }
  131. /*
  132. * Allocate the video buffers.
  133. */
  134. static int uvc_alloc_buffers(struct uvc_video_queue *queue,
  135. struct v4l2_requestbuffers *rb)
  136. {
  137. int ret;
  138. mutex_lock(&queue->mutex);
  139. ret = vb2_reqbufs(&queue->queue, rb);
  140. mutex_unlock(&queue->mutex);
  141. return ret ? ret : rb->count;
  142. }
  143. static int uvc_query_buffer(struct uvc_video_queue *queue,
  144. struct v4l2_buffer *buf)
  145. {
  146. int ret;
  147. mutex_lock(&queue->mutex);
  148. ret = vb2_querybuf(&queue->queue, buf);
  149. mutex_unlock(&queue->mutex);
  150. return ret;
  151. }
  152. static int uvc_queue_buffer(struct uvc_video_queue *queue,
  153. struct v4l2_buffer *buf)
  154. {
  155. unsigned long flags;
  156. int ret;
  157. mutex_lock(&queue->mutex);
  158. ret = vb2_qbuf(&queue->queue, buf);
  159. spin_lock_irqsave(&queue->irqlock, flags);
  160. ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
  161. queue->flags &= ~UVC_QUEUE_PAUSED;
  162. spin_unlock_irqrestore(&queue->irqlock, flags);
  163. mutex_unlock(&queue->mutex);
  164. return ret;
  165. }
  166. /*
  167. * Dequeue a video buffer. If nonblocking is false, block until a buffer is
  168. * available.
  169. */
  170. static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
  171. struct v4l2_buffer *buf, int nonblocking)
  172. {
  173. int ret;
  174. mutex_lock(&queue->mutex);
  175. ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
  176. mutex_unlock(&queue->mutex);
  177. return ret;
  178. }
  179. /*
  180. * Poll the video queue.
  181. *
  182. * This function implements video queue polling and is intended to be used by
  183. * the device poll handler.
  184. */
  185. static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
  186. struct file *file, poll_table *wait)
  187. {
  188. unsigned int ret;
  189. mutex_lock(&queue->mutex);
  190. ret = vb2_poll(&queue->queue, file, wait);
  191. mutex_unlock(&queue->mutex);
  192. return ret;
  193. }
  194. static int uvc_queue_mmap(struct uvc_video_queue *queue,
  195. struct vm_area_struct *vma)
  196. {
  197. int ret;
  198. mutex_lock(&queue->mutex);
  199. ret = vb2_mmap(&queue->queue, vma);
  200. mutex_unlock(&queue->mutex);
  201. return ret;
  202. }
  203. #ifndef CONFIG_MMU
  204. /*
  205. * Get unmapped area.
  206. *
  207. * NO-MMU arch need this function to make mmap() work correctly.
  208. */
  209. static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
  210. unsigned long pgoff)
  211. {
  212. unsigned long ret;
  213. mutex_lock(&queue->mutex);
  214. ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
  215. mutex_unlock(&queue->mutex);
  216. return ret;
  217. }
  218. #endif
  219. /*
  220. * Cancel the video buffers queue.
  221. *
  222. * Cancelling the queue marks all buffers on the irq queue as erroneous,
  223. * wakes them up and removes them from the queue.
  224. *
  225. * If the disconnect parameter is set, further calls to uvc_queue_buffer will
  226. * fail with -ENODEV.
  227. *
  228. * This function acquires the irq spinlock and can be called from interrupt
  229. * context.
  230. */
  231. static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
  232. {
  233. struct uvc_buffer *buf;
  234. unsigned long flags;
  235. spin_lock_irqsave(&queue->irqlock, flags);
  236. while (!list_empty(&queue->irqqueue)) {
  237. buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
  238. queue);
  239. list_del(&buf->queue);
  240. buf->state = UVC_BUF_STATE_ERROR;
  241. vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
  242. }
  243. /* This must be protected by the irqlock spinlock to avoid race
  244. * conditions between uvc_queue_buffer and the disconnection event that
  245. * could result in an interruptible wait in uvc_dequeue_buffer. Do not
  246. * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
  247. * state outside the queue code.
  248. */
  249. if (disconnect)
  250. queue->flags |= UVC_QUEUE_DISCONNECTED;
  251. spin_unlock_irqrestore(&queue->irqlock, flags);
  252. }
  253. /*
  254. * Enable or disable the video buffers queue.
  255. *
  256. * The queue must be enabled before starting video acquisition and must be
  257. * disabled after stopping it. This ensures that the video buffers queue
  258. * state can be properly initialized before buffers are accessed from the
  259. * interrupt handler.
  260. *
  261. * Enabling the video queue initializes parameters (such as sequence number,
  262. * sync pattern, ...). If the queue is already enabled, return -EBUSY.
  263. *
  264. * Disabling the video queue cancels the queue and removes all buffers from
  265. * the main queue.
  266. *
  267. * This function can't be called from interrupt context. Use
  268. * uvc_queue_cancel() instead.
  269. */
  270. static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
  271. {
  272. unsigned long flags;
  273. int ret = 0;
  274. mutex_lock(&queue->mutex);
  275. if (enable) {
  276. ret = vb2_streamon(&queue->queue, queue->queue.type);
  277. if (ret < 0)
  278. goto done;
  279. queue->sequence = 0;
  280. queue->buf_used = 0;
  281. } else {
  282. ret = vb2_streamoff(&queue->queue, queue->queue.type);
  283. if (ret < 0)
  284. goto done;
  285. spin_lock_irqsave(&queue->irqlock, flags);
  286. INIT_LIST_HEAD(&queue->irqqueue);
  287. /*
  288. * FIXME: We need to clear the DISCONNECTED flag to ensure that
  289. * applications will be able to queue buffers for the next
  290. * streaming run. However, clearing it here doesn't guarantee
  291. * that the device will be reconnected in the meantime.
  292. */
  293. queue->flags &= ~UVC_QUEUE_DISCONNECTED;
  294. spin_unlock_irqrestore(&queue->irqlock, flags);
  295. }
  296. done:
  297. mutex_unlock(&queue->mutex);
  298. return ret;
  299. }
  300. /* called with &queue_irqlock held.. */
  301. static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
  302. struct uvc_buffer *buf)
  303. {
  304. struct uvc_buffer *nextbuf;
  305. if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
  306. buf->length != buf->bytesused) {
  307. buf->state = UVC_BUF_STATE_QUEUED;
  308. vb2_set_plane_payload(&buf->buf, 0, 0);
  309. return buf;
  310. }
  311. list_del(&buf->queue);
  312. if (!list_empty(&queue->irqqueue))
  313. nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
  314. queue);
  315. else
  316. nextbuf = NULL;
  317. /*
  318. * FIXME: with videobuf2, the sequence number or timestamp fields
  319. * are valid only for video capture devices and the UVC gadget usually
  320. * is a video output device. Keeping these until the specs are clear on
  321. * this aspect.
  322. */
  323. buf->buf.v4l2_buf.sequence = queue->sequence++;
  324. do_gettimeofday(&buf->buf.v4l2_buf.timestamp);
  325. vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
  326. vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
  327. return nextbuf;
  328. }
  329. static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue)
  330. {
  331. struct uvc_buffer *buf = NULL;
  332. if (!list_empty(&queue->irqqueue))
  333. buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
  334. queue);
  335. else
  336. queue->flags |= UVC_QUEUE_PAUSED;
  337. return buf;
  338. }