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cdda479f LP |
1 | /* |
2 | * uvc_video.c -- USB Video Class Gadget driver | |
3 | * | |
4 | * Copyright (C) 2009-2010 | |
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 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/device.h> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/usb/ch9.h> | |
18 | #include <linux/usb/gadget.h> | |
19 | ||
20 | #include <media/v4l2-dev.h> | |
21 | ||
22 | #include "uvc.h" | |
23 | #include "uvc_queue.h" | |
24 | ||
25 | /* -------------------------------------------------------------------------- | |
26 | * Video codecs | |
27 | */ | |
28 | ||
29 | static int | |
30 | uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf, | |
31 | u8 *data, int len) | |
32 | { | |
33 | data[0] = 2; | |
34 | data[1] = UVC_STREAM_EOH | video->fid; | |
35 | ||
36 | if (buf->buf.bytesused - video->queue.buf_used <= len - 2) | |
37 | data[1] |= UVC_STREAM_EOF; | |
38 | ||
39 | return 2; | |
40 | } | |
41 | ||
42 | static int | |
43 | uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf, | |
44 | u8 *data, int len) | |
45 | { | |
46 | struct uvc_video_queue *queue = &video->queue; | |
47 | unsigned int nbytes; | |
48 | void *mem; | |
49 | ||
50 | /* Copy video data to the USB buffer. */ | |
51 | mem = queue->mem + buf->buf.m.offset + queue->buf_used; | |
52 | nbytes = min((unsigned int)len, buf->buf.bytesused - queue->buf_used); | |
53 | ||
54 | memcpy(data, mem, nbytes); | |
55 | queue->buf_used += nbytes; | |
56 | ||
57 | return nbytes; | |
58 | } | |
59 | ||
60 | static void | |
61 | uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video, | |
62 | struct uvc_buffer *buf) | |
63 | { | |
64 | void *mem = req->buf; | |
65 | int len = video->req_size; | |
66 | int ret; | |
67 | ||
68 | /* Add a header at the beginning of the payload. */ | |
69 | if (video->payload_size == 0) { | |
70 | ret = uvc_video_encode_header(video, buf, mem, len); | |
71 | video->payload_size += ret; | |
72 | mem += ret; | |
73 | len -= ret; | |
74 | } | |
75 | ||
76 | /* Process video data. */ | |
77 | len = min((int)(video->max_payload_size - video->payload_size), len); | |
78 | ret = uvc_video_encode_data(video, buf, mem, len); | |
79 | ||
80 | video->payload_size += ret; | |
81 | len -= ret; | |
82 | ||
83 | req->length = video->req_size - len; | |
84 | req->zero = video->payload_size == video->max_payload_size; | |
85 | ||
86 | if (buf->buf.bytesused == video->queue.buf_used) { | |
87 | video->queue.buf_used = 0; | |
88 | buf->state = UVC_BUF_STATE_DONE; | |
89 | uvc_queue_next_buffer(&video->queue, buf); | |
90 | video->fid ^= UVC_STREAM_FID; | |
91 | ||
92 | video->payload_size = 0; | |
93 | } | |
94 | ||
95 | if (video->payload_size == video->max_payload_size || | |
96 | buf->buf.bytesused == video->queue.buf_used) | |
97 | video->payload_size = 0; | |
98 | } | |
99 | ||
100 | static void | |
101 | uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video, | |
102 | struct uvc_buffer *buf) | |
103 | { | |
104 | void *mem = req->buf; | |
105 | int len = video->req_size; | |
106 | int ret; | |
107 | ||
108 | /* Add the header. */ | |
109 | ret = uvc_video_encode_header(video, buf, mem, len); | |
110 | mem += ret; | |
111 | len -= ret; | |
112 | ||
113 | /* Process video data. */ | |
114 | ret = uvc_video_encode_data(video, buf, mem, len); | |
115 | len -= ret; | |
116 | ||
117 | req->length = video->req_size - len; | |
118 | ||
119 | if (buf->buf.bytesused == video->queue.buf_used) { | |
120 | video->queue.buf_used = 0; | |
121 | buf->state = UVC_BUF_STATE_DONE; | |
122 | uvc_queue_next_buffer(&video->queue, buf); | |
123 | video->fid ^= UVC_STREAM_FID; | |
124 | } | |
125 | } | |
126 | ||
127 | /* -------------------------------------------------------------------------- | |
128 | * Request handling | |
129 | */ | |
130 | ||
131 | /* | |
132 | * I somehow feel that synchronisation won't be easy to achieve here. We have | |
133 | * three events that control USB requests submission: | |
134 | * | |
135 | * - USB request completion: the completion handler will resubmit the request | |
136 | * if a video buffer is available. | |
137 | * | |
138 | * - USB interface setting selection: in response to a SET_INTERFACE request, | |
139 | * the handler will start streaming if a video buffer is available and if | |
140 | * video is not currently streaming. | |
141 | * | |
142 | * - V4L2 buffer queueing: the driver will start streaming if video is not | |
143 | * currently streaming. | |
144 | * | |
145 | * Race conditions between those 3 events might lead to deadlocks or other | |
146 | * nasty side effects. | |
147 | * | |
148 | * The "video currently streaming" condition can't be detected by the irqqueue | |
149 | * being empty, as a request can still be in flight. A separate "queue paused" | |
150 | * flag is thus needed. | |
151 | * | |
152 | * The paused flag will be set when we try to retrieve the irqqueue head if the | |
153 | * queue is empty, and cleared when we queue a buffer. | |
154 | * | |
155 | * The USB request completion handler will get the buffer at the irqqueue head | |
156 | * under protection of the queue spinlock. If the queue is empty, the streaming | |
157 | * paused flag will be set. Right after releasing the spinlock a userspace | |
158 | * application can queue a buffer. The flag will then cleared, and the ioctl | |
159 | * handler will restart the video stream. | |
160 | */ | |
161 | static void | |
162 | uvc_video_complete(struct usb_ep *ep, struct usb_request *req) | |
163 | { | |
164 | struct uvc_video *video = req->context; | |
165 | struct uvc_buffer *buf; | |
166 | unsigned long flags; | |
167 | int ret; | |
168 | ||
169 | switch (req->status) { | |
170 | case 0: | |
171 | break; | |
172 | ||
173 | case -ESHUTDOWN: | |
174 | printk(KERN_INFO "VS request cancelled.\n"); | |
175 | goto requeue; | |
176 | ||
177 | default: | |
178 | printk(KERN_INFO "VS request completed with status %d.\n", | |
179 | req->status); | |
180 | goto requeue; | |
181 | } | |
182 | ||
183 | spin_lock_irqsave(&video->queue.irqlock, flags); | |
184 | buf = uvc_queue_head(&video->queue); | |
185 | if (buf == NULL) { | |
186 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
187 | goto requeue; | |
188 | } | |
189 | ||
190 | video->encode(req, video, buf); | |
191 | ||
192 | if ((ret = usb_ep_queue(ep, req, GFP_ATOMIC)) < 0) { | |
193 | printk(KERN_INFO "Failed to queue request (%d).\n", ret); | |
194 | usb_ep_set_halt(ep); | |
195 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
196 | goto requeue; | |
197 | } | |
198 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
199 | ||
200 | return; | |
201 | ||
202 | requeue: | |
203 | spin_lock_irqsave(&video->req_lock, flags); | |
204 | list_add_tail(&req->list, &video->req_free); | |
205 | spin_unlock_irqrestore(&video->req_lock, flags); | |
206 | } | |
207 | ||
208 | static int | |
209 | uvc_video_free_requests(struct uvc_video *video) | |
210 | { | |
211 | unsigned int i; | |
212 | ||
213 | for (i = 0; i < UVC_NUM_REQUESTS; ++i) { | |
214 | if (video->req[i]) { | |
215 | usb_ep_free_request(video->ep, video->req[i]); | |
216 | video->req[i] = NULL; | |
217 | } | |
218 | ||
219 | if (video->req_buffer[i]) { | |
220 | kfree(video->req_buffer[i]); | |
221 | video->req_buffer[i] = NULL; | |
222 | } | |
223 | } | |
224 | ||
225 | INIT_LIST_HEAD(&video->req_free); | |
226 | video->req_size = 0; | |
227 | return 0; | |
228 | } | |
229 | ||
230 | static int | |
231 | uvc_video_alloc_requests(struct uvc_video *video) | |
232 | { | |
233 | unsigned int i; | |
234 | int ret = -ENOMEM; | |
235 | ||
236 | BUG_ON(video->req_size); | |
237 | ||
238 | for (i = 0; i < UVC_NUM_REQUESTS; ++i) { | |
239 | video->req_buffer[i] = kmalloc(video->ep->maxpacket, GFP_KERNEL); | |
240 | if (video->req_buffer[i] == NULL) | |
241 | goto error; | |
242 | ||
243 | video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL); | |
244 | if (video->req[i] == NULL) | |
245 | goto error; | |
246 | ||
247 | video->req[i]->buf = video->req_buffer[i]; | |
248 | video->req[i]->length = 0; | |
249 | video->req[i]->dma = DMA_ADDR_INVALID; | |
250 | video->req[i]->complete = uvc_video_complete; | |
251 | video->req[i]->context = video; | |
252 | ||
253 | list_add_tail(&video->req[i]->list, &video->req_free); | |
254 | } | |
255 | ||
256 | video->req_size = video->ep->maxpacket; | |
257 | return 0; | |
258 | ||
259 | error: | |
260 | uvc_video_free_requests(video); | |
261 | return ret; | |
262 | } | |
263 | ||
264 | /* -------------------------------------------------------------------------- | |
265 | * Video streaming | |
266 | */ | |
267 | ||
268 | /* | |
269 | * uvc_video_pump - Pump video data into the USB requests | |
270 | * | |
271 | * This function fills the available USB requests (listed in req_free) with | |
272 | * video data from the queued buffers. | |
273 | */ | |
5d9955f8 | 274 | static int |
cdda479f LP |
275 | uvc_video_pump(struct uvc_video *video) |
276 | { | |
277 | struct usb_request *req; | |
278 | struct uvc_buffer *buf; | |
279 | unsigned long flags; | |
280 | int ret; | |
281 | ||
282 | /* FIXME TODO Race between uvc_video_pump and requests completion | |
283 | * handler ??? | |
284 | */ | |
285 | ||
286 | while (1) { | |
287 | /* Retrieve the first available USB request, protected by the | |
288 | * request lock. | |
289 | */ | |
290 | spin_lock_irqsave(&video->req_lock, flags); | |
291 | if (list_empty(&video->req_free)) { | |
292 | spin_unlock_irqrestore(&video->req_lock, flags); | |
293 | return 0; | |
294 | } | |
295 | req = list_first_entry(&video->req_free, struct usb_request, | |
296 | list); | |
297 | list_del(&req->list); | |
298 | spin_unlock_irqrestore(&video->req_lock, flags); | |
299 | ||
300 | /* Retrieve the first available video buffer and fill the | |
301 | * request, protected by the video queue irqlock. | |
302 | */ | |
303 | spin_lock_irqsave(&video->queue.irqlock, flags); | |
304 | buf = uvc_queue_head(&video->queue); | |
305 | if (buf == NULL) { | |
306 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
307 | break; | |
308 | } | |
309 | ||
310 | video->encode(req, video, buf); | |
311 | ||
312 | /* Queue the USB request */ | |
313 | if ((ret = usb_ep_queue(video->ep, req, GFP_KERNEL)) < 0) { | |
314 | printk(KERN_INFO "Failed to queue request (%d)\n", ret); | |
315 | usb_ep_set_halt(video->ep); | |
316 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
317 | break; | |
318 | } | |
319 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
320 | } | |
321 | ||
322 | spin_lock_irqsave(&video->req_lock, flags); | |
323 | list_add_tail(&req->list, &video->req_free); | |
324 | spin_unlock_irqrestore(&video->req_lock, flags); | |
325 | return 0; | |
326 | } | |
327 | ||
328 | /* | |
329 | * Enable or disable the video stream. | |
330 | */ | |
5d9955f8 | 331 | static int |
cdda479f LP |
332 | uvc_video_enable(struct uvc_video *video, int enable) |
333 | { | |
334 | unsigned int i; | |
335 | int ret; | |
336 | ||
337 | if (video->ep == NULL) { | |
338 | printk(KERN_INFO "Video enable failed, device is " | |
339 | "uninitialized.\n"); | |
340 | return -ENODEV; | |
341 | } | |
342 | ||
343 | if (!enable) { | |
344 | for (i = 0; i < UVC_NUM_REQUESTS; ++i) | |
345 | usb_ep_dequeue(video->ep, video->req[i]); | |
346 | ||
347 | uvc_video_free_requests(video); | |
348 | uvc_queue_enable(&video->queue, 0); | |
349 | return 0; | |
350 | } | |
351 | ||
352 | if ((ret = uvc_queue_enable(&video->queue, 1)) < 0) | |
353 | return ret; | |
354 | ||
355 | if ((ret = uvc_video_alloc_requests(video)) < 0) | |
356 | return ret; | |
357 | ||
358 | if (video->max_payload_size) { | |
359 | video->encode = uvc_video_encode_bulk; | |
360 | video->payload_size = 0; | |
361 | } else | |
362 | video->encode = uvc_video_encode_isoc; | |
363 | ||
364 | return uvc_video_pump(video); | |
365 | } | |
366 | ||
367 | /* | |
368 | * Initialize the UVC video stream. | |
369 | */ | |
5d9955f8 | 370 | static int |
cdda479f LP |
371 | uvc_video_init(struct uvc_video *video) |
372 | { | |
373 | INIT_LIST_HEAD(&video->req_free); | |
374 | spin_lock_init(&video->req_lock); | |
375 | ||
376 | video->fcc = V4L2_PIX_FMT_YUYV; | |
377 | video->bpp = 16; | |
378 | video->width = 320; | |
379 | video->height = 240; | |
380 | video->imagesize = 320 * 240 * 2; | |
381 | ||
382 | /* Initialize the video buffers queue. */ | |
383 | uvc_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT); | |
384 | return 0; | |
385 | } | |
386 |