1// SPDX-License-Identifier: GPL-2.0+
2/*
3 *	uvc_video.c  --  USB Video Class Gadget driver
4 *
5 *	Copyright (C) 2009-2010
6 *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
7 */
8
9#include <linux/kernel.h>
10#include <linux/device.h>
11#include <linux/errno.h>
12#include <linux/usb/ch9.h>
13#include <linux/usb/gadget.h>
14#include <linux/usb/video.h>
15
16#include <media/v4l2-dev.h>
17
18#include "uvc.h"
19#include "uvc_queue.h"
20#include "uvc_video.h"
21
22/* --------------------------------------------------------------------------
23 * Video codecs
24 */
25
26static int
27uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
28		u8 *data, int len)
29{
30	data[0] = 2;
31	data[1] = UVC_STREAM_EOH | video->fid;
32
33	if (buf->bytesused - video->queue.buf_used <= len - 2)
34		data[1] |= UVC_STREAM_EOF;
35
36	return 2;
37}
38
39static int
40uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
41		u8 *data, int len)
42{
43	struct uvc_video_queue *queue = &video->queue;
44	unsigned int nbytes;
45	void *mem;
46
47	/* Copy video data to the USB buffer. */
48	mem = buf->mem + queue->buf_used;
49	nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);
50
51	memcpy(data, mem, nbytes);
52	queue->buf_used += nbytes;
53
54	return nbytes;
55}
56
57static void
58uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
59		struct uvc_buffer *buf)
60{
61	void *mem = req->buf;
62	int len = video->req_size;
63	int ret;
64
65	/* Add a header at the beginning of the payload. */
66	if (video->payload_size == 0) {
67		ret = uvc_video_encode_header(video, buf, mem, len);
68		video->payload_size += ret;
69		mem += ret;
70		len -= ret;
71	}
72
73	/* Process video data. */
74	len = min((int)(video->max_payload_size - video->payload_size), len);
75	ret = uvc_video_encode_data(video, buf, mem, len);
76
77	video->payload_size += ret;
78	len -= ret;
79
80	req->length = video->req_size - len;
81	req->zero = video->payload_size == video->max_payload_size;
82
83	if (buf->bytesused == video->queue.buf_used) {
84		video->queue.buf_used = 0;
85		buf->state = UVC_BUF_STATE_DONE;
86		uvcg_queue_next_buffer(&video->queue, buf);
87		video->fid ^= UVC_STREAM_FID;
88
89		video->payload_size = 0;
90	}
91
92	if (video->payload_size == video->max_payload_size ||
93	    buf->bytesused == video->queue.buf_used)
94		video->payload_size = 0;
95}
96
97static void
98uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
99		struct uvc_buffer *buf)
100{
101	void *mem = req->buf;
102	int len = video->req_size;
103	int ret;
104
105	/* Add the header. */
106	ret = uvc_video_encode_header(video, buf, mem, len);
107	mem += ret;
108	len -= ret;
109
110	/* Process video data. */
111	ret = uvc_video_encode_data(video, buf, mem, len);
112	len -= ret;
113
114	req->length = video->req_size - len;
115
116	if (buf->bytesused == video->queue.buf_used) {
117		video->queue.buf_used = 0;
118		buf->state = UVC_BUF_STATE_DONE;
119		uvcg_queue_next_buffer(&video->queue, buf);
120		video->fid ^= UVC_STREAM_FID;
121	}
122}
123
124/* --------------------------------------------------------------------------
125 * Request handling
126 */
127
128static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
129{
130	int ret;
131
132	ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
133	if (ret < 0) {
134		uvcg_err(&video->uvc->func, "Failed to queue request (%d).\n",
135			 ret);
136
137		/* Isochronous endpoints can't be halted. */
138		if (usb_endpoint_xfer_bulk(video->ep->desc))
139			usb_ep_set_halt(video->ep);
140	}
141
142	return ret;
143}
144
145static void
146uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
147{
148	struct uvc_video *video = req->context;
149	struct uvc_video_queue *queue = &video->queue;
150	unsigned long flags;
151
152	switch (req->status) {
153	case 0:
154		break;
155
156	case -ESHUTDOWN:	/* disconnect from host. */
157		uvcg_dbg(&video->uvc->func, "VS request cancelled.\n");
158		uvcg_queue_cancel(queue, 1);
159		break;
160
161	default:
162		uvcg_warn(&video->uvc->func,
163			  "VS request completed with status %d.\n",
164			  req->status);
165		uvcg_queue_cancel(queue, 0);
166	}
167
168	spin_lock_irqsave(&video->req_lock, flags);
169	list_add_tail(&req->list, &video->req_free);
170	spin_unlock_irqrestore(&video->req_lock, flags);
171
172	schedule_work(&video->pump);
173}
174
175static int
176uvc_video_free_requests(struct uvc_video *video)
177{
178	unsigned int i;
179
180	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
181		if (video->req[i]) {
182			usb_ep_free_request(video->ep, video->req[i]);
183			video->req[i] = NULL;
184		}
185
186		if (video->req_buffer[i]) {
187			kfree(video->req_buffer[i]);
188			video->req_buffer[i] = NULL;
189		}
190	}
191
192	INIT_LIST_HEAD(&video->req_free);
193	video->req_size = 0;
194	return 0;
195}
196
197static int
198uvc_video_alloc_requests(struct uvc_video *video)
199{
200	unsigned int req_size;
201	unsigned int i;
202	int ret = -ENOMEM;
203
204	BUG_ON(video->req_size);
205
206	req_size = video->ep->maxpacket
207		 * max_t(unsigned int, video->ep->maxburst, 1)
208		 * (video->ep->mult);
209
210	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
211		video->req_buffer[i] = kmalloc(req_size, GFP_KERNEL);
212		if (video->req_buffer[i] == NULL)
213			goto error;
214
215		video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL);
216		if (video->req[i] == NULL)
217			goto error;
218
219		video->req[i]->buf = video->req_buffer[i];
220		video->req[i]->length = 0;
221		video->req[i]->complete = uvc_video_complete;
222		video->req[i]->context = video;
223
224		list_add_tail(&video->req[i]->list, &video->req_free);
225	}
226
227	video->req_size = req_size;
228
229	return 0;
230
231error:
232	uvc_video_free_requests(video);
233	return ret;
234}
235
236/* --------------------------------------------------------------------------
237 * Video streaming
238 */
239
240/*
241 * uvcg_video_pump - Pump video data into the USB requests
242 *
243 * This function fills the available USB requests (listed in req_free) with
244 * video data from the queued buffers.
245 */
246static void uvcg_video_pump(struct work_struct *work)
247{
248	struct uvc_video *video = container_of(work, struct uvc_video, pump);
249	struct uvc_video_queue *queue = &video->queue;
250	struct usb_request *req;
251	struct uvc_buffer *buf;
252	unsigned long flags;
253	int ret;
254
255	while (1) {
256		/* Retrieve the first available USB request, protected by the
257		 * request lock.
258		 */
259		spin_lock_irqsave(&video->req_lock, flags);
260		if (list_empty(&video->req_free)) {
261			spin_unlock_irqrestore(&video->req_lock, flags);
262			return;
263		}
264		req = list_first_entry(&video->req_free, struct usb_request,
265					list);
266		list_del(&req->list);
267		spin_unlock_irqrestore(&video->req_lock, flags);
268
269		/* Retrieve the first available video buffer and fill the
270		 * request, protected by the video queue irqlock.
271		 */
272		spin_lock_irqsave(&queue->irqlock, flags);
273		buf = uvcg_queue_head(queue);
274		if (buf == NULL) {
275			spin_unlock_irqrestore(&queue->irqlock, flags);
276			break;
277		}
278
279		video->encode(req, video, buf);
280
281		/* Queue the USB request */
282		ret = uvcg_video_ep_queue(video, req);
283		spin_unlock_irqrestore(&queue->irqlock, flags);
284
285		if (ret < 0) {
286			uvcg_queue_cancel(queue, 0);
287			break;
288		}
289	}
290
291	spin_lock_irqsave(&video->req_lock, flags);
292	list_add_tail(&req->list, &video->req_free);
293	spin_unlock_irqrestore(&video->req_lock, flags);
294	return;
295}
296
297/*
298 * Enable or disable the video stream.
299 */
300int uvcg_video_enable(struct uvc_video *video, int enable)
301{
302	unsigned int i;
303	int ret;
304
305	if (video->ep == NULL) {
306		uvcg_info(&video->uvc->func,
307			  "Video enable failed, device is uninitialized.\n");
308		return -ENODEV;
309	}
310
311	if (!enable) {
312		cancel_work_sync(&video->pump);
313		uvcg_queue_cancel(&video->queue, 0);
314
315		for (i = 0; i < UVC_NUM_REQUESTS; ++i)
316			if (video->req[i])
317				usb_ep_dequeue(video->ep, video->req[i]);
318
319		uvc_video_free_requests(video);
320		uvcg_queue_enable(&video->queue, 0);
321		return 0;
322	}
323
324	if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
325		return ret;
326
327	if ((ret = uvc_video_alloc_requests(video)) < 0)
328		return ret;
329
330	if (video->max_payload_size) {
331		video->encode = uvc_video_encode_bulk;
332		video->payload_size = 0;
333	} else
334		video->encode = uvc_video_encode_isoc;
335
336	schedule_work(&video->pump);
337
338	return ret;
339}
340
341/*
342 * Initialize the UVC video stream.
343 */
344int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
345{
346	INIT_LIST_HEAD(&video->req_free);
347	spin_lock_init(&video->req_lock);
348	INIT_WORK(&video->pump, uvcg_video_pump);
349
350	video->uvc = uvc;
351	video->fcc = V4L2_PIX_FMT_YUYV;
352	video->bpp = 16;
353	video->width = 320;
354	video->height = 240;
355	video->imagesize = 320 * 240 * 2;
356
357	/* Initialize the video buffers queue. */
358	uvcg_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT,
359			&video->mutex);
360	return 0;
361}
362
363