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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. | |
cdda479f LP |
11 | */ |
12 | ||
13 | #include <linux/kernel.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/usb/ch9.h> | |
17 | #include <linux/usb/gadget.h> | |
18 | ||
19 | #include <media/v4l2-dev.h> | |
20 | ||
21 | #include "uvc.h" | |
22 | #include "uvc_queue.h" | |
23 | ||
24 | /* -------------------------------------------------------------------------- | |
25 | * Video codecs | |
26 | */ | |
27 | ||
28 | static int | |
29 | uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf, | |
30 | u8 *data, int len) | |
31 | { | |
32 | data[0] = 2; | |
33 | data[1] = UVC_STREAM_EOH | video->fid; | |
34 | ||
35 | if (buf->buf.bytesused - video->queue.buf_used <= len - 2) | |
36 | data[1] |= UVC_STREAM_EOF; | |
37 | ||
38 | return 2; | |
39 | } | |
40 | ||
41 | static int | |
42 | uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf, | |
43 | u8 *data, int len) | |
44 | { | |
45 | struct uvc_video_queue *queue = &video->queue; | |
46 | unsigned int nbytes; | |
47 | void *mem; | |
48 | ||
49 | /* Copy video data to the USB buffer. */ | |
50 | mem = queue->mem + buf->buf.m.offset + queue->buf_used; | |
51 | nbytes = min((unsigned int)len, buf->buf.bytesused - queue->buf_used); | |
52 | ||
53 | memcpy(data, mem, nbytes); | |
54 | queue->buf_used += nbytes; | |
55 | ||
56 | return nbytes; | |
57 | } | |
58 | ||
59 | static void | |
60 | uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video, | |
61 | struct uvc_buffer *buf) | |
62 | { | |
63 | void *mem = req->buf; | |
64 | int len = video->req_size; | |
65 | int ret; | |
66 | ||
67 | /* Add a header at the beginning of the payload. */ | |
68 | if (video->payload_size == 0) { | |
69 | ret = uvc_video_encode_header(video, buf, mem, len); | |
70 | video->payload_size += ret; | |
71 | mem += ret; | |
72 | len -= ret; | |
73 | } | |
74 | ||
75 | /* Process video data. */ | |
76 | len = min((int)(video->max_payload_size - video->payload_size), len); | |
77 | ret = uvc_video_encode_data(video, buf, mem, len); | |
78 | ||
79 | video->payload_size += ret; | |
80 | len -= ret; | |
81 | ||
82 | req->length = video->req_size - len; | |
83 | req->zero = video->payload_size == video->max_payload_size; | |
84 | ||
85 | if (buf->buf.bytesused == video->queue.buf_used) { | |
86 | video->queue.buf_used = 0; | |
87 | buf->state = UVC_BUF_STATE_DONE; | |
88 | uvc_queue_next_buffer(&video->queue, buf); | |
89 | video->fid ^= UVC_STREAM_FID; | |
90 | ||
91 | video->payload_size = 0; | |
92 | } | |
93 | ||
94 | if (video->payload_size == video->max_payload_size || | |
95 | buf->buf.bytesused == video->queue.buf_used) | |
96 | video->payload_size = 0; | |
97 | } | |
98 | ||
99 | static void | |
100 | uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video, | |
101 | struct uvc_buffer *buf) | |
102 | { | |
103 | void *mem = req->buf; | |
104 | int len = video->req_size; | |
105 | int ret; | |
106 | ||
107 | /* Add the header. */ | |
108 | ret = uvc_video_encode_header(video, buf, mem, len); | |
109 | mem += ret; | |
110 | len -= ret; | |
111 | ||
112 | /* Process video data. */ | |
113 | ret = uvc_video_encode_data(video, buf, mem, len); | |
114 | len -= ret; | |
115 | ||
116 | req->length = video->req_size - len; | |
117 | ||
118 | if (buf->buf.bytesused == video->queue.buf_used) { | |
119 | video->queue.buf_used = 0; | |
120 | buf->state = UVC_BUF_STATE_DONE; | |
121 | uvc_queue_next_buffer(&video->queue, buf); | |
122 | video->fid ^= UVC_STREAM_FID; | |
123 | } | |
124 | } | |
125 | ||
126 | /* -------------------------------------------------------------------------- | |
127 | * Request handling | |
128 | */ | |
129 | ||
130 | /* | |
131 | * I somehow feel that synchronisation won't be easy to achieve here. We have | |
132 | * three events that control USB requests submission: | |
133 | * | |
134 | * - USB request completion: the completion handler will resubmit the request | |
135 | * if a video buffer is available. | |
136 | * | |
137 | * - USB interface setting selection: in response to a SET_INTERFACE request, | |
138 | * the handler will start streaming if a video buffer is available and if | |
139 | * video is not currently streaming. | |
140 | * | |
141 | * - V4L2 buffer queueing: the driver will start streaming if video is not | |
142 | * currently streaming. | |
143 | * | |
144 | * Race conditions between those 3 events might lead to deadlocks or other | |
145 | * nasty side effects. | |
146 | * | |
147 | * The "video currently streaming" condition can't be detected by the irqqueue | |
148 | * being empty, as a request can still be in flight. A separate "queue paused" | |
149 | * flag is thus needed. | |
150 | * | |
151 | * The paused flag will be set when we try to retrieve the irqqueue head if the | |
152 | * queue is empty, and cleared when we queue a buffer. | |
153 | * | |
154 | * The USB request completion handler will get the buffer at the irqqueue head | |
155 | * under protection of the queue spinlock. If the queue is empty, the streaming | |
156 | * paused flag will be set. Right after releasing the spinlock a userspace | |
157 | * application can queue a buffer. The flag will then cleared, and the ioctl | |
158 | * handler will restart the video stream. | |
159 | */ | |
160 | static void | |
161 | uvc_video_complete(struct usb_ep *ep, struct usb_request *req) | |
162 | { | |
163 | struct uvc_video *video = req->context; | |
164 | struct uvc_buffer *buf; | |
165 | unsigned long flags; | |
166 | int ret; | |
167 | ||
168 | switch (req->status) { | |
169 | case 0: | |
170 | break; | |
171 | ||
172 | case -ESHUTDOWN: | |
173 | printk(KERN_INFO "VS request cancelled.\n"); | |
174 | goto requeue; | |
175 | ||
176 | default: | |
177 | printk(KERN_INFO "VS request completed with status %d.\n", | |
178 | req->status); | |
179 | goto requeue; | |
180 | } | |
181 | ||
182 | spin_lock_irqsave(&video->queue.irqlock, flags); | |
183 | buf = uvc_queue_head(&video->queue); | |
184 | if (buf == NULL) { | |
185 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
186 | goto requeue; | |
187 | } | |
188 | ||
189 | video->encode(req, video, buf); | |
190 | ||
191 | if ((ret = usb_ep_queue(ep, req, GFP_ATOMIC)) < 0) { | |
192 | printk(KERN_INFO "Failed to queue request (%d).\n", ret); | |
193 | usb_ep_set_halt(ep); | |
194 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
195 | goto requeue; | |
196 | } | |
197 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
198 | ||
199 | return; | |
200 | ||
201 | requeue: | |
202 | spin_lock_irqsave(&video->req_lock, flags); | |
203 | list_add_tail(&req->list, &video->req_free); | |
204 | spin_unlock_irqrestore(&video->req_lock, flags); | |
205 | } | |
206 | ||
207 | static int | |
208 | uvc_video_free_requests(struct uvc_video *video) | |
209 | { | |
210 | unsigned int i; | |
211 | ||
212 | for (i = 0; i < UVC_NUM_REQUESTS; ++i) { | |
213 | if (video->req[i]) { | |
214 | usb_ep_free_request(video->ep, video->req[i]); | |
215 | video->req[i] = NULL; | |
216 | } | |
217 | ||
218 | if (video->req_buffer[i]) { | |
219 | kfree(video->req_buffer[i]); | |
220 | video->req_buffer[i] = NULL; | |
221 | } | |
222 | } | |
223 | ||
224 | INIT_LIST_HEAD(&video->req_free); | |
225 | video->req_size = 0; | |
226 | return 0; | |
227 | } | |
228 | ||
229 | static int | |
230 | uvc_video_alloc_requests(struct uvc_video *video) | |
231 | { | |
232 | unsigned int i; | |
233 | int ret = -ENOMEM; | |
234 | ||
235 | BUG_ON(video->req_size); | |
236 | ||
237 | for (i = 0; i < UVC_NUM_REQUESTS; ++i) { | |
238 | video->req_buffer[i] = kmalloc(video->ep->maxpacket, GFP_KERNEL); | |
239 | if (video->req_buffer[i] == NULL) | |
240 | goto error; | |
241 | ||
242 | video->req[i] = usb_ep_alloc_request(video->ep, GFP_KERNEL); | |
243 | if (video->req[i] == NULL) | |
244 | goto error; | |
245 | ||
246 | video->req[i]->buf = video->req_buffer[i]; | |
247 | video->req[i]->length = 0; | |
248 | video->req[i]->dma = DMA_ADDR_INVALID; | |
249 | video->req[i]->complete = uvc_video_complete; | |
250 | video->req[i]->context = video; | |
251 | ||
252 | list_add_tail(&video->req[i]->list, &video->req_free); | |
253 | } | |
254 | ||
255 | video->req_size = video->ep->maxpacket; | |
256 | return 0; | |
257 | ||
258 | error: | |
259 | uvc_video_free_requests(video); | |
260 | return ret; | |
261 | } | |
262 | ||
263 | /* -------------------------------------------------------------------------- | |
264 | * Video streaming | |
265 | */ | |
266 | ||
267 | /* | |
268 | * uvc_video_pump - Pump video data into the USB requests | |
269 | * | |
270 | * This function fills the available USB requests (listed in req_free) with | |
271 | * video data from the queued buffers. | |
272 | */ | |
5d9955f8 | 273 | static int |
cdda479f LP |
274 | uvc_video_pump(struct uvc_video *video) |
275 | { | |
276 | struct usb_request *req; | |
277 | struct uvc_buffer *buf; | |
278 | unsigned long flags; | |
279 | int ret; | |
280 | ||
281 | /* FIXME TODO Race between uvc_video_pump and requests completion | |
282 | * handler ??? | |
283 | */ | |
284 | ||
285 | while (1) { | |
286 | /* Retrieve the first available USB request, protected by the | |
287 | * request lock. | |
288 | */ | |
289 | spin_lock_irqsave(&video->req_lock, flags); | |
290 | if (list_empty(&video->req_free)) { | |
291 | spin_unlock_irqrestore(&video->req_lock, flags); | |
292 | return 0; | |
293 | } | |
294 | req = list_first_entry(&video->req_free, struct usb_request, | |
295 | list); | |
296 | list_del(&req->list); | |
297 | spin_unlock_irqrestore(&video->req_lock, flags); | |
298 | ||
299 | /* Retrieve the first available video buffer and fill the | |
300 | * request, protected by the video queue irqlock. | |
301 | */ | |
302 | spin_lock_irqsave(&video->queue.irqlock, flags); | |
303 | buf = uvc_queue_head(&video->queue); | |
304 | if (buf == NULL) { | |
305 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
306 | break; | |
307 | } | |
308 | ||
309 | video->encode(req, video, buf); | |
310 | ||
311 | /* Queue the USB request */ | |
312 | if ((ret = usb_ep_queue(video->ep, req, GFP_KERNEL)) < 0) { | |
313 | printk(KERN_INFO "Failed to queue request (%d)\n", ret); | |
314 | usb_ep_set_halt(video->ep); | |
315 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
316 | break; | |
317 | } | |
318 | spin_unlock_irqrestore(&video->queue.irqlock, flags); | |
319 | } | |
320 | ||
321 | spin_lock_irqsave(&video->req_lock, flags); | |
322 | list_add_tail(&req->list, &video->req_free); | |
323 | spin_unlock_irqrestore(&video->req_lock, flags); | |
324 | return 0; | |
325 | } | |
326 | ||
327 | /* | |
328 | * Enable or disable the video stream. | |
329 | */ | |
5d9955f8 | 330 | static int |
cdda479f LP |
331 | uvc_video_enable(struct uvc_video *video, int enable) |
332 | { | |
333 | unsigned int i; | |
334 | int ret; | |
335 | ||
336 | if (video->ep == NULL) { | |
337 | printk(KERN_INFO "Video enable failed, device is " | |
338 | "uninitialized.\n"); | |
339 | return -ENODEV; | |
340 | } | |
341 | ||
342 | if (!enable) { | |
343 | for (i = 0; i < UVC_NUM_REQUESTS; ++i) | |
344 | usb_ep_dequeue(video->ep, video->req[i]); | |
345 | ||
346 | uvc_video_free_requests(video); | |
347 | uvc_queue_enable(&video->queue, 0); | |
348 | return 0; | |
349 | } | |
350 | ||
351 | if ((ret = uvc_queue_enable(&video->queue, 1)) < 0) | |
352 | return ret; | |
353 | ||
354 | if ((ret = uvc_video_alloc_requests(video)) < 0) | |
355 | return ret; | |
356 | ||
357 | if (video->max_payload_size) { | |
358 | video->encode = uvc_video_encode_bulk; | |
359 | video->payload_size = 0; | |
360 | } else | |
361 | video->encode = uvc_video_encode_isoc; | |
362 | ||
363 | return uvc_video_pump(video); | |
364 | } | |
365 | ||
366 | /* | |
367 | * Initialize the UVC video stream. | |
368 | */ | |
5d9955f8 | 369 | static int |
cdda479f LP |
370 | uvc_video_init(struct uvc_video *video) |
371 | { | |
372 | INIT_LIST_HEAD(&video->req_free); | |
373 | spin_lock_init(&video->req_lock); | |
374 | ||
375 | video->fcc = V4L2_PIX_FMT_YUYV; | |
376 | video->bpp = 16; | |
377 | video->width = 320; | |
378 | video->height = 240; | |
379 | video->imagesize = 320 * 240 * 2; | |
380 | ||
381 | /* Initialize the video buffers queue. */ | |
382 | uvc_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT); | |
383 | return 0; | |
384 | } | |
385 |