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
44static int uvc_queue_setup(struct vb2_queue *vq, const void *parg,
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
61static 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
87static 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
109static 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
117int 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 */
145void uvcg_free_buffers(struct uvc_video_queue *queue)
146{
147	vb2_queue_release(&queue->queue);
148}
149
150/*
151 * Allocate the video buffers.
152 */
153int 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
163int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
164{
165	return vb2_querybuf(&queue->queue, buf);
166}
167
168int 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 */
188int 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 */
200unsigned 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
206int 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 */
217unsigned 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 */
236void 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 */
277int 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.. */
311struct 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	v4l2_get_timestamp(&buf->buf.timestamp);
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
340struct 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
353