Laurent Pinchart | cdda479 | 2010-05-02 20:57:41 +0200 | [diff] [blame] | 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. |
Laurent Pinchart | cdda479 | 2010-05-02 20:57:41 +0200 | [diff] [blame] | 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 | */ |
Laurent Pinchart | 5d9955f | 2010-07-10 16:13:05 -0300 | [diff] [blame] | 273 | static int |
Laurent Pinchart | cdda479 | 2010-05-02 20:57:41 +0200 | [diff] [blame] | 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 | */ |
Laurent Pinchart | 5d9955f | 2010-07-10 16:13:05 -0300 | [diff] [blame] | 330 | static int |
Laurent Pinchart | cdda479 | 2010-05-02 20:57:41 +0200 | [diff] [blame] | 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 | */ |
Laurent Pinchart | 5d9955f | 2010-07-10 16:13:05 -0300 | [diff] [blame] | 369 | static int |
Laurent Pinchart | cdda479 | 2010-05-02 20:57:41 +0200 | [diff] [blame] | 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 | |