drivers/usb/gadget/function/uvc_video.c

   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
  26 static int
  27 uvc_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
  39 static int
  40 uvc_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
  57 static void
  58 uvc_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
  97 static void
  98 uvc_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
 128 static 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
 145 static void
 146 uvc_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_info(&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
 175 static int
 176 uvc_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
 197 static int
 198 uvc_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
 231 error:
 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  */
 246 static 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  */
 300 int 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  */
 344 int 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