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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
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
43static 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
60static 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
85static 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
106static 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
113static 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
120static 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
128static 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 */
154static 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 */
164static 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
176static 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
188static 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
204done:
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 */
213static 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 */
231static 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
243static 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 */
261static 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 */
285static 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 */
326static 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
357done:
358 mutex_unlock(&queue->mutex);
359 return ret;
360}
361
362/* called with &queue_irqlock held.. */
363static 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
397static 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