1// SPDX-License-Identifier: GPL-2.0+
2/*
3 *	uvc_queue.c  --  USB Video Class driver - Buffers management
4 *
5 *	Copyright (C) 2005-2010
6 *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
7 */
8
9#include <linux/atomic.h>
10#include <linux/kernel.h>
11#include <linux/mm.h>
12#include <linux/list.h>
13#include <linux/module.h>
14#include <linux/usb.h>
15#include <linux/videodev2.h>
16#include <linux/vmalloc.h>
17#include <linux/wait.h>
18
19#include <media/v4l2-common.h>
20#include <media/videobuf2-vmalloc.h>
21
22#include "uvc.h"
23
24/* ------------------------------------------------------------------------
25 * Video buffers queue management.
26 *
27 * Video queues is initialized by uvcg_queue_init(). The function performs
28 * basic initialization of the uvc_video_queue struct and never fails.
29 *
30 * Video buffers are managed by videobuf2. The driver uses a mutex to protect
31 * the videobuf2 queue operations by serializing calls to videobuf2 and a
32 * spinlock to protect the IRQ queue that holds the buffers to be processed by
33 * the driver.
34 */
35
36/* -----------------------------------------------------------------------------
37 * videobuf2 queue operations
38 */
39
40static int uvc_queue_setup(struct vb2_queue *vq,
41			   unsigned int *nbuffers, unsigned int *nplanes,
42			   unsigned int sizes[], struct device *alloc_devs[])
43{
44	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
45	struct uvc_video *video = container_of(queue, struct uvc_video, queue);
46
47	if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
48		*nbuffers = UVC_MAX_VIDEO_BUFFERS;
49
50	*nplanes = 1;
51
52	sizes[0] = video->imagesize;
53
54	return 0;
55}
56
57static int uvc_buffer_prepare(struct vb2_buffer *vb)
58{
59	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
60	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
61	struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf);
62
63	if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
64	    vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
65		uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
66		return -EINVAL;
67	}
68
69	if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
70		return -ENODEV;
71
72	buf->state = UVC_BUF_STATE_QUEUED;
73	buf->mem = vb2_plane_vaddr(vb, 0);
74	buf->length = vb2_plane_size(vb, 0);
75	if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
76		buf->bytesused = 0;
77	else
78		buf->bytesused = vb2_get_plane_payload(vb, 0);
79
80	return 0;
81}
82
83static void uvc_buffer_queue(struct vb2_buffer *vb)
84{
85	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
86	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
87	struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf);
88	unsigned long flags;
89
90	spin_lock_irqsave(&queue->irqlock, flags);
91
92	if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
93		list_add_tail(&buf->queue, &queue->irqqueue);
94	} else {
95		/* If the device is disconnected return the buffer to userspace
96		 * directly. The next QBUF call will fail with -ENODEV.
97		 */
98		buf->state = UVC_BUF_STATE_ERROR;
99		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
100	}
101
102	spin_unlock_irqrestore(&queue->irqlock, flags);
103}
104
105static const struct vb2_ops uvc_queue_qops = {
106	.queue_setup = uvc_queue_setup,
107	.buf_prepare = uvc_buffer_prepare,
108	.buf_queue = uvc_buffer_queue,
109	.wait_prepare = vb2_ops_wait_prepare,
110	.wait_finish = vb2_ops_wait_finish,
111};
112
113int uvcg_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
114		    struct mutex *lock)
115{
116	int ret;
117
118	queue->queue.type = type;
119	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
120	queue->queue.drv_priv = queue;
121	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
122	queue->queue.ops = &uvc_queue_qops;
123	queue->queue.lock = lock;
124	queue->queue.mem_ops = &vb2_vmalloc_memops;
125	queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
126				     | V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
127	ret = vb2_queue_init(&queue->queue);
128	if (ret)
129		return ret;
130
131	spin_lock_init(&queue->irqlock);
132	INIT_LIST_HEAD(&queue->irqqueue);
133	queue->flags = 0;
134
135	return 0;
136}
137
138/*
139 * Free the video buffers.
140 */
141void uvcg_free_buffers(struct uvc_video_queue *queue)
142{
143	vb2_queue_release(&queue->queue);
144}
145
146/*
147 * Allocate the video buffers.
148 */
149int uvcg_alloc_buffers(struct uvc_video_queue *queue,
150			      struct v4l2_requestbuffers *rb)
151{
152	int ret;
153
154	ret = vb2_reqbufs(&queue->queue, rb);
155
156	return ret ? ret : rb->count;
157}
158
159int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
160{
161	return vb2_querybuf(&queue->queue, buf);
162}
163
164int uvcg_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
165{
166	unsigned long flags;
167	int ret;
168
169	ret = vb2_qbuf(&queue->queue, NULL, buf);
170	if (ret < 0)
171		return ret;
172
173	spin_lock_irqsave(&queue->irqlock, flags);
174	ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
175	queue->flags &= ~UVC_QUEUE_PAUSED;
176	spin_unlock_irqrestore(&queue->irqlock, flags);
177	return ret;
178}
179
180/*
181 * Dequeue a video buffer. If nonblocking is false, block until a buffer is
182 * available.
183 */
184int uvcg_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
185			int nonblocking)
186{
187	return vb2_dqbuf(&queue->queue, buf, nonblocking);
188}
189
190/*
191 * Poll the video queue.
192 *
193 * This function implements video queue polling and is intended to be used by
194 * the device poll handler.
195 */
196__poll_t uvcg_queue_poll(struct uvc_video_queue *queue, struct file *file,
197			     poll_table *wait)
198{
199	return vb2_poll(&queue->queue, file, wait);
200}
201
202int uvcg_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
203{
204	return vb2_mmap(&queue->queue, vma);
205}
206
207#ifndef CONFIG_MMU
208/*
209 * Get unmapped area.
210 *
211 * NO-MMU arch need this function to make mmap() work correctly.
212 */
213unsigned long uvcg_queue_get_unmapped_area(struct uvc_video_queue *queue,
214					   unsigned long pgoff)
215{
216	return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
217}
218#endif
219
220/*
221 * Cancel the video buffers queue.
222 *
223 * Cancelling the queue marks all buffers on the irq queue as erroneous,
224 * wakes them up and removes them from the queue.
225 *
226 * If the disconnect parameter is set, further calls to uvc_queue_buffer will
227 * fail with -ENODEV.
228 *
229 * This function acquires the irq spinlock and can be called from interrupt
230 * context.
231 */
232void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
233{
234	struct uvc_buffer *buf;
235	unsigned long flags;
236
237	spin_lock_irqsave(&queue->irqlock, flags);
238	while (!list_empty(&queue->irqqueue)) {
239		buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
240				       queue);
241		list_del(&buf->queue);
242		buf->state = UVC_BUF_STATE_ERROR;
243		vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
244	}
245	queue->buf_used = 0;
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.vb2_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.field = V4L2_FIELD_NONE;
329	buf->buf.sequence = queue->sequence++;
330	buf->buf.vb2_buf.timestamp = ktime_get_ns();
331
332	vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused);
333	vb2_buffer_done(&buf->buf.vb2_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