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 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
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 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
86static 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
107static 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
115int 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 */
143void uvcg_free_buffers(struct uvc_video_queue *queue)
144{
145	vb2_queue_release(&queue->queue);
146}
147
148/*
149 * Allocate the video buffers.
150 */
151int 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
161int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
162{
163	return vb2_querybuf(&queue->queue, buf);
164}
165
166int 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 */
186int 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 */
198unsigned 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
204int 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 */
215unsigned 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 */
234void 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 */
275int 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.. */
309struct 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
338struct 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
351