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-dma-sg.h>
21 #include <media/videobuf2-vmalloc.h>
22 
23 #include "uvc.h"
24 
25 /* ------------------------------------------------------------------------
26  * Video buffers queue management.
27  *
28  * Video queues is initialized by uvcg_queue_init(). The function performs
29  * basic initialization of the uvc_video_queue struct and never fails.
30  *
31  * Video buffers are managed by videobuf2. The driver uses a mutex to protect
32  * the videobuf2 queue operations by serializing calls to videobuf2 and a
33  * spinlock to protect the IRQ queue that holds the buffers to be processed by
34  * the driver.
35  */
36 
37 /* -----------------------------------------------------------------------------
38  * videobuf2 queue operations
39  */
40 
41 static int uvc_queue_setup(struct vb2_queue *vq,
42 			   unsigned int *nbuffers, unsigned int *nplanes,
43 			   unsigned int sizes[], struct device *alloc_devs[])
44 {
45 	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
46 	struct uvc_video *video = container_of(queue, struct uvc_video, queue);
47 	unsigned int req_size;
48 	unsigned int nreq;
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 	req_size = video->ep->maxpacket
58 		 * max_t(unsigned int, video->ep->maxburst, 1)
59 		 * (video->ep->mult);
60 
61 	/* We divide by two, to increase the chance to run
62 	 * into fewer requests for smaller framesizes.
63 	 */
64 	nreq = DIV_ROUND_UP(DIV_ROUND_UP(sizes[0], 2), req_size);
65 	nreq = clamp(nreq, 4U, 64U);
66 	video->uvc_num_requests = nreq;
67 
68 	return 0;
69 }
70 
71 static int uvc_buffer_prepare(struct vb2_buffer *vb)
72 {
73 	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
74 	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
75 	struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf);
76 
77 	if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
78 	    vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
79 		uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
80 		return -EINVAL;
81 	}
82 
83 	if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
84 		return -ENODEV;
85 
86 	buf->state = UVC_BUF_STATE_QUEUED;
87 	if (queue->use_sg) {
88 		buf->sgt = vb2_dma_sg_plane_desc(vb, 0);
89 		buf->sg = buf->sgt->sgl;
90 	} else {
91 		buf->mem = vb2_plane_vaddr(vb, 0);
92 	}
93 	buf->length = vb2_plane_size(vb, 0);
94 	if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
95 		buf->bytesused = 0;
96 	else
97 		buf->bytesused = vb2_get_plane_payload(vb, 0);
98 
99 	return 0;
100 }
101 
102 static void uvc_buffer_queue(struct vb2_buffer *vb)
103 {
104 	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
105 	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
106 	struct uvc_buffer *buf = container_of(vbuf, struct uvc_buffer, buf);
107 	unsigned long flags;
108 
109 	spin_lock_irqsave(&queue->irqlock, flags);
110 
111 	if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
112 		list_add_tail(&buf->queue, &queue->irqqueue);
113 	} else {
114 		/*
115 		 * If the device is disconnected return the buffer to userspace
116 		 * directly. The next QBUF call will fail with -ENODEV.
117 		 */
118 		buf->state = UVC_BUF_STATE_ERROR;
119 		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
120 	}
121 
122 	spin_unlock_irqrestore(&queue->irqlock, flags);
123 }
124 
125 static const struct vb2_ops uvc_queue_qops = {
126 	.queue_setup = uvc_queue_setup,
127 	.buf_prepare = uvc_buffer_prepare,
128 	.buf_queue = uvc_buffer_queue,
129 	.wait_prepare = vb2_ops_wait_prepare,
130 	.wait_finish = vb2_ops_wait_finish,
131 };
132 
133 int uvcg_queue_init(struct uvc_video_queue *queue, struct device *dev, enum v4l2_buf_type type,
134 		    struct mutex *lock)
135 {
136 	struct uvc_video *video = container_of(queue, struct uvc_video, queue);
137 	struct usb_composite_dev *cdev = video->uvc->func.config->cdev;
138 	int ret;
139 
140 	queue->queue.type = type;
141 	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
142 	queue->queue.drv_priv = queue;
143 	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
144 	queue->queue.ops = &uvc_queue_qops;
145 	queue->queue.lock = lock;
146 	if (cdev->gadget->sg_supported) {
147 		queue->queue.mem_ops = &vb2_dma_sg_memops;
148 		queue->use_sg = 1;
149 	} else {
150 		queue->queue.mem_ops = &vb2_vmalloc_memops;
151 	}
152 
153 	queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY
154 				     | V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
155 	queue->queue.dev = dev;
156 
157 	ret = vb2_queue_init(&queue->queue);
158 	if (ret)
159 		return ret;
160 
161 	spin_lock_init(&queue->irqlock);
162 	INIT_LIST_HEAD(&queue->irqqueue);
163 	queue->flags = 0;
164 
165 	return 0;
166 }
167 
168 /*
169  * Free the video buffers.
170  */
171 void uvcg_free_buffers(struct uvc_video_queue *queue)
172 {
173 	vb2_queue_release(&queue->queue);
174 }
175 
176 /*
177  * Allocate the video buffers.
178  */
179 int uvcg_alloc_buffers(struct uvc_video_queue *queue,
180 			      struct v4l2_requestbuffers *rb)
181 {
182 	int ret;
183 
184 	ret = vb2_reqbufs(&queue->queue, rb);
185 
186 	return ret ? ret : rb->count;
187 }
188 
189 int uvcg_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
190 {
191 	return vb2_querybuf(&queue->queue, buf);
192 }
193 
194 int uvcg_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf)
195 {
196 	return vb2_qbuf(&queue->queue, NULL, buf);
197 }
198 
199 /*
200  * Dequeue a video buffer. If nonblocking is false, block until a buffer is
201  * available.
202  */
203 int uvcg_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
204 			int nonblocking)
205 {
206 	return vb2_dqbuf(&queue->queue, buf, nonblocking);
207 }
208 
209 /*
210  * Poll the video queue.
211  *
212  * This function implements video queue polling and is intended to be used by
213  * the device poll handler.
214  */
215 __poll_t uvcg_queue_poll(struct uvc_video_queue *queue, struct file *file,
216 			     poll_table *wait)
217 {
218 	return vb2_poll(&queue->queue, file, wait);
219 }
220 
221 int uvcg_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
222 {
223 	return vb2_mmap(&queue->queue, vma);
224 }
225 
226 #ifndef CONFIG_MMU
227 /*
228  * Get unmapped area.
229  *
230  * NO-MMU arch need this function to make mmap() work correctly.
231  */
232 unsigned long uvcg_queue_get_unmapped_area(struct uvc_video_queue *queue,
233 					   unsigned long pgoff)
234 {
235 	return vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
236 }
237 #endif
238 
239 /*
240  * Cancel the video buffers queue.
241  *
242  * Cancelling the queue marks all buffers on the irq queue as erroneous,
243  * wakes them up and removes them from the queue.
244  *
245  * If the disconnect parameter is set, further calls to uvc_queue_buffer will
246  * fail with -ENODEV.
247  *
248  * This function acquires the irq spinlock and can be called from interrupt
249  * context.
250  */
251 void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
252 {
253 	struct uvc_buffer *buf;
254 	unsigned long flags;
255 
256 	spin_lock_irqsave(&queue->irqlock, flags);
257 	while (!list_empty(&queue->irqqueue)) {
258 		buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
259 				       queue);
260 		list_del(&buf->queue);
261 		buf->state = UVC_BUF_STATE_ERROR;
262 		vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
263 	}
264 	queue->buf_used = 0;
265 
266 	/*
267 	 * This must be protected by the irqlock spinlock to avoid race
268 	 * conditions between uvc_queue_buffer and the disconnection event that
269 	 * could result in an interruptible wait in uvc_dequeue_buffer. Do not
270 	 * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
271 	 * state outside the queue code.
272 	 */
273 	if (disconnect)
274 		queue->flags |= UVC_QUEUE_DISCONNECTED;
275 	spin_unlock_irqrestore(&queue->irqlock, flags);
276 }
277 
278 /*
279  * Enable or disable the video buffers queue.
280  *
281  * The queue must be enabled before starting video acquisition and must be
282  * disabled after stopping it. This ensures that the video buffers queue
283  * state can be properly initialized before buffers are accessed from the
284  * interrupt handler.
285  *
286  * Enabling the video queue initializes parameters (such as sequence number,
287  * sync pattern, ...). If the queue is already enabled, return -EBUSY.
288  *
289  * Disabling the video queue cancels the queue and removes all buffers from
290  * the main queue.
291  *
292  * This function can't be called from interrupt context. Use
293  * uvcg_queue_cancel() instead.
294  */
295 int uvcg_queue_enable(struct uvc_video_queue *queue, int enable)
296 {
297 	unsigned long flags;
298 	int ret = 0;
299 
300 	if (enable) {
301 		ret = vb2_streamon(&queue->queue, queue->queue.type);
302 		if (ret < 0)
303 			return ret;
304 
305 		queue->sequence = 0;
306 		queue->buf_used = 0;
307 		queue->flags &= ~UVC_QUEUE_DROP_INCOMPLETE;
308 	} else {
309 		ret = vb2_streamoff(&queue->queue, queue->queue.type);
310 		if (ret < 0)
311 			return ret;
312 
313 		spin_lock_irqsave(&queue->irqlock, flags);
314 		INIT_LIST_HEAD(&queue->irqqueue);
315 
316 		/*
317 		 * FIXME: We need to clear the DISCONNECTED flag to ensure that
318 		 * applications will be able to queue buffers for the next
319 		 * streaming run. However, clearing it here doesn't guarantee
320 		 * that the device will be reconnected in the meantime.
321 		 */
322 		queue->flags &= ~UVC_QUEUE_DISCONNECTED;
323 		spin_unlock_irqrestore(&queue->irqlock, flags);
324 	}
325 
326 	return ret;
327 }
328 
329 /* called with &queue_irqlock held.. */
330 void uvcg_complete_buffer(struct uvc_video_queue *queue,
331 					  struct uvc_buffer *buf)
332 {
333 	if (queue->flags & UVC_QUEUE_DROP_INCOMPLETE) {
334 		queue->flags &= ~UVC_QUEUE_DROP_INCOMPLETE;
335 		buf->state = UVC_BUF_STATE_ERROR;
336 		vb2_set_plane_payload(&buf->buf.vb2_buf, 0, 0);
337 		vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
338 		return;
339 	}
340 
341 	buf->buf.field = V4L2_FIELD_NONE;
342 	buf->buf.sequence = queue->sequence++;
343 	buf->buf.vb2_buf.timestamp = ktime_get_ns();
344 
345 	vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused);
346 	vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_DONE);
347 }
348 
349 struct uvc_buffer *uvcg_queue_head(struct uvc_video_queue *queue)
350 {
351 	struct uvc_buffer *buf = NULL;
352 
353 	if (!list_empty(&queue->irqqueue))
354 		buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
355 				       queue);
356 
357 	return buf;
358 }
359 
360