drivers/media/video/cx18/cx18-streams.c

   1 /*
   2  *  cx18 init/start/stop/exit stream functions
   3  *
   4  *  Derived from ivtv-streams.c
   5  *
   6  *  Copyright (C) 2007  Hans Verkuil <hverkuil@xs4all.nl>
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  21  *  02111-1307  USA
  22  */
  23
  24 #include "cx18-driver.h"
  25 #include "cx18-fileops.h"
  26 #include "cx18-mailbox.h"
  27 #include "cx18-i2c.h"
  28 #include "cx18-queue.h"
  29 #include "cx18-ioctl.h"
  30 #include "cx18-streams.h"
  31 #include "cx18-cards.h"
  32 #include "cx18-scb.h"
  33 #include "cx18-av-core.h"
  34 #include "cx18-dvb.h"
  35
  36 #define CX18_DSP0_INTERRUPT_MASK        0xd0004C
  37
  38 static struct file_operations cx18_v4l2_enc_fops = {
  39         .owner = THIS_MODULE,
  40         .read = cx18_v4l2_read,
  41         .open = cx18_v4l2_open,
  42         /* FIXME change to video_ioctl2 if serialization lock can be removed */
  43         .ioctl = cx18_v4l2_ioctl,
  44         .compat_ioctl = v4l_compat_ioctl32,
  45         .release = cx18_v4l2_close,
  46         .poll = cx18_v4l2_enc_poll,
  47 };
  48
  49 /* offset from 0 to register ts v4l2 minors on */
  50 #define CX18_V4L2_ENC_TS_OFFSET   16
  51 /* offset from 0 to register pcm v4l2 minors on */
  52 #define CX18_V4L2_ENC_PCM_OFFSET  24
  53 /* offset from 0 to register yuv v4l2 minors on */
  54 #define CX18_V4L2_ENC_YUV_OFFSET  32
  55
  56 static struct {
  57         const char *name;
  58         int vfl_type;
  59         int minor_offset;
  60         int dma;
  61         enum v4l2_buf_type buf_type;
  62         struct file_operations *fops;
  63 } cx18_stream_info[] = {
  64         {       /* CX18_ENC_STREAM_TYPE_MPG */
  65                 "encoder MPEG",
  66                 VFL_TYPE_GRABBER, 0,
  67                 PCI_DMA_FROMDEVICE, V4L2_BUF_TYPE_VIDEO_CAPTURE,
  68                 &cx18_v4l2_enc_fops
  69         },
  70         {       /* CX18_ENC_STREAM_TYPE_TS */
  71                 "TS",
  72                 VFL_TYPE_GRABBER, -1,
  73                 PCI_DMA_FROMDEVICE, V4L2_BUF_TYPE_VIDEO_CAPTURE,
  74                 &cx18_v4l2_enc_fops
  75         },
  76         {       /* CX18_ENC_STREAM_TYPE_YUV */
  77                 "encoder YUV",
  78                 VFL_TYPE_GRABBER, CX18_V4L2_ENC_YUV_OFFSET,
  79                 PCI_DMA_FROMDEVICE, V4L2_BUF_TYPE_VIDEO_CAPTURE,
  80                 &cx18_v4l2_enc_fops
  81         },
  82         {       /* CX18_ENC_STREAM_TYPE_VBI */
  83                 "encoder VBI",
  84                 VFL_TYPE_VBI, 0,
  85                 PCI_DMA_FROMDEVICE, V4L2_BUF_TYPE_VBI_CAPTURE,
  86                 &cx18_v4l2_enc_fops
  87         },
  88         {       /* CX18_ENC_STREAM_TYPE_PCM */
  89                 "encoder PCM audio",
  90                 VFL_TYPE_GRABBER, CX18_V4L2_ENC_PCM_OFFSET,
  91                 PCI_DMA_FROMDEVICE, V4L2_BUF_TYPE_PRIVATE,
  92                 &cx18_v4l2_enc_fops
  93         },
  94         {       /* CX18_ENC_STREAM_TYPE_IDX */
  95                 "encoder IDX",
  96                 VFL_TYPE_GRABBER, -1,
  97                 PCI_DMA_FROMDEVICE, V4L2_BUF_TYPE_VIDEO_CAPTURE,
  98                 &cx18_v4l2_enc_fops
  99         },
 100         {       /* CX18_ENC_STREAM_TYPE_RAD */
 101                 "encoder radio",
 102                 VFL_TYPE_RADIO, 0,
 103                 PCI_DMA_NONE, V4L2_BUF_TYPE_PRIVATE,
 104                 &cx18_v4l2_enc_fops
 105         },
 106 };
 107
 108 static void cx18_stream_init(struct cx18 *cx, int type)
 109 {
 110         struct cx18_stream *s = &cx->streams[type];
 111         struct video_device *dev = s->v4l2dev;
 112         u32 max_size = cx->options.megabytes[type] * 1024 * 1024;
 113
 114         /* we need to keep v4l2dev, so restore it afterwards */
 115         memset(s, 0, sizeof(*s));
 116         s->v4l2dev = dev;
 117
 118         /* initialize cx18_stream fields */
 119         s->cx = cx;
 120         s->type = type;
 121         s->name = cx18_stream_info[type].name;
 122         s->handle = 0xffffffff;
 123
 124         s->dma = cx18_stream_info[type].dma;
 125         s->buf_size = cx->stream_buf_size[type];
 126         if (s->buf_size)
 127                 s->buffers = max_size / s->buf_size;
 128         if (s->buffers > 63) {
 129                 /* Each stream has a maximum of 63 buffers,
 130                    ensure we do not exceed that. */
 131                 s->buffers = 63;
 132                 s->buf_size = (max_size / s->buffers) & ~0xfff;
 133         }
 134         spin_lock_init(&s->qlock);
 135         init_waitqueue_head(&s->waitq);
 136         s->id = -1;
 137         cx18_queue_init(&s->q_free);
 138         cx18_queue_init(&s->q_full);
 139         cx18_queue_init(&s->q_io);
 140 }
 141
 142 static int cx18_prep_dev(struct cx18 *cx, int type)
 143 {
 144         struct cx18_stream *s = &cx->streams[type];
 145         u32 cap = cx->v4l2_cap;
 146         int minor_offset = cx18_stream_info[type].minor_offset;
 147         int minor;
 148
 149         /* These four fields are always initialized. If v4l2dev == NULL, then
 150            this stream is not in use. In that case no other fields but these
 151            four can be used. */
 152         s->v4l2dev = NULL;
 153         s->cx = cx;
 154         s->type = type;
 155         s->name = cx18_stream_info[type].name;
 156
 157         /* Check whether the radio is supported */
 158         if (type == CX18_ENC_STREAM_TYPE_RAD && !(cap & V4L2_CAP_RADIO))
 159                 return 0;
 160
 161         /* Check whether VBI is supported */
 162         if (type == CX18_ENC_STREAM_TYPE_VBI &&
 163             !(cap & (V4L2_CAP_VBI_CAPTURE | V4L2_CAP_SLICED_VBI_CAPTURE)))
 164                 return 0;
 165
 166         /* card number + user defined offset + device offset */
 167         minor = cx->num + cx18_first_minor + minor_offset;
 168
 169         /* User explicitly selected 0 buffers for these streams, so don't
 170            create them. */
 171         if (cx18_stream_info[type].dma != PCI_DMA_NONE &&
 172             cx->options.megabytes[type] == 0) {
 173                 CX18_INFO("Disabled %s device\n", cx18_stream_info[type].name);
 174                 return 0;
 175         }
 176
 177         cx18_stream_init(cx, type);
 178
 179         if (minor_offset == -1)
 180                 return 0;
 181
 182         /* allocate and initialize the v4l2 video device structure */
 183         s->v4l2dev = video_device_alloc();
 184         if (s->v4l2dev == NULL) {
 185                 CX18_ERR("Couldn't allocate v4l2 video_device for %s\n",
 186                                 s->name);
 187                 return -ENOMEM;
 188         }
 189
 190         s->v4l2dev->type =
 191                 VID_TYPE_CAPTURE | VID_TYPE_TUNER | VID_TYPE_TELETEXT |
 192                 VID_TYPE_CLIPPING | VID_TYPE_SCALES | VID_TYPE_MPEG_ENCODER;
 193         snprintf(s->v4l2dev->name, sizeof(s->v4l2dev->name), "cx18-%d",
 194                         cx->num);
 195
 196         s->v4l2dev->minor = minor;
 197         s->v4l2dev->dev = &cx->dev->dev;
 198         s->v4l2dev->fops = cx18_stream_info[type].fops;
 199         s->v4l2dev->release = video_device_release;
 200         s->v4l2dev->tvnorms = V4L2_STD_ALL;
 201         cx18_set_funcs(s->v4l2dev);
 202         return 0;
 203 }
 204
 205 /* Initialize v4l2 variables and register v4l2 devices */
 206 int cx18_streams_setup(struct cx18 *cx)
 207 {
 208         int type;
 209
 210         /* Setup V4L2 Devices */
 211         for (type = 0; type < CX18_MAX_STREAMS; type++) {
 212                 /* Prepare device */
 213                 if (cx18_prep_dev(cx, type))
 214                         break;
 215
 216                 /* Allocate Stream */
 217                 if (cx18_stream_alloc(&cx->streams[type]))
 218                         break;
 219         }
 220         if (type == CX18_MAX_STREAMS)
 221                 return 0;
 222
 223         /* One or more streams could not be initialized. Clean 'em all up. */
 224         cx18_streams_cleanup(cx, 0);
 225         return -ENOMEM;
 226 }
 227
 228 static int cx18_reg_dev(struct cx18 *cx, int type)
 229 {
 230         struct cx18_stream *s = &cx->streams[type];
 231         int vfl_type = cx18_stream_info[type].vfl_type;
 232         int minor;
 233
 234         /* TODO: Shouldn't this be a VFL_TYPE_TRANSPORT or something?
 235          * We need a VFL_TYPE_TS defined.
 236          */
 237         if (strcmp("TS", s->name) == 0) {
 238                 /* just return if no DVB is supported */
 239                 if ((cx->card->hw_all & CX18_HW_DVB) == 0)
 240                         return 0;
 241                 if (cx18_dvb_register(s) < 0) {
 242                         CX18_ERR("DVB failed to register\n");
 243                         return -EINVAL;
 244                 }
 245         }
 246
 247         if (s->v4l2dev == NULL)
 248                 return 0;
 249
 250         minor = s->v4l2dev->minor;
 251
 252         /* Register device. First try the desired minor, then any free one. */
 253         if (video_register_device(s->v4l2dev, vfl_type, minor) &&
 254                         video_register_device(s->v4l2dev, vfl_type, -1)) {
 255                 CX18_ERR("Couldn't register v4l2 device for %s minor %d\n",
 256                         s->name, minor);
 257                 video_device_release(s->v4l2dev);
 258                 s->v4l2dev = NULL;
 259                 return -ENOMEM;
 260         }
 261         minor = s->v4l2dev->minor;
 262
 263         switch (vfl_type) {
 264         case VFL_TYPE_GRABBER:
 265                 CX18_INFO("Registered device video%d for %s (%d MB)\n",
 266                         minor, s->name, cx->options.megabytes[type]);
 267                 break;
 268
 269         case VFL_TYPE_RADIO:
 270                 CX18_INFO("Registered device radio%d for %s\n",
 271                         minor - MINOR_VFL_TYPE_RADIO_MIN, s->name);
 272                 break;
 273
 274         case VFL_TYPE_VBI:
 275                 if (cx->options.megabytes[type])
 276                         CX18_INFO("Registered device vbi%d for %s (%d MB)\n",
 277                                 minor - MINOR_VFL_TYPE_VBI_MIN,
 278                                 s->name, cx->options.megabytes[type]);
 279                 else
 280                         CX18_INFO("Registered device vbi%d for %s\n",
 281                                 minor - MINOR_VFL_TYPE_VBI_MIN, s->name);
 282                 break;
 283         }
 284
 285         return 0;
 286 }
 287
 288 /* Register v4l2 devices */
 289 int cx18_streams_register(struct cx18 *cx)
 290 {
 291         int type;
 292         int err = 0;
 293
 294         /* Register V4L2 devices */
 295         for (type = 0; type < CX18_MAX_STREAMS; type++)
 296                 err |= cx18_reg_dev(cx, type);
 297
 298         if (err == 0)
 299                 return 0;
 300
 301         /* One or more streams could not be initialized. Clean 'em all up. */
 302         cx18_streams_cleanup(cx, 1);
 303         return -ENOMEM;
 304 }
 305
 306 /* Unregister v4l2 devices */
 307 void cx18_streams_cleanup(struct cx18 *cx, int unregister)
 308 {
 309         struct video_device *vdev;
 310         int type;
 311
 312         /* Teardown all streams */
 313         for (type = 0; type < CX18_MAX_STREAMS; type++) {
 314                 if (cx->streams[type].dvb.enabled) {
 315                         cx18_dvb_unregister(&cx->streams[type]);
 316                         cx->streams[type].dvb.enabled = false;
 317                 }
 318
 319                 vdev = cx->streams[type].v4l2dev;
 320
 321                 cx->streams[type].v4l2dev = NULL;
 322                 if (vdev == NULL)
 323                         continue;
 324
 325                 cx18_stream_free(&cx->streams[type]);
 326
 327                 /* Unregister or release device */
 328                 if (unregister)
 329                         video_unregister_device(vdev);
 330                 else
 331                         video_device_release(vdev);
 332         }
 333 }
 334
 335 static void cx18_vbi_setup(struct cx18_stream *s)
 336 {
 337         struct cx18 *cx = s->cx;
 338         int raw = cx->vbi.sliced_in->service_set == 0;
 339         u32 data[CX2341X_MBOX_MAX_DATA];
 340         int lines;
 341
 342         if (cx->is_60hz) {
 343                 cx->vbi.count = 12;
 344                 cx->vbi.start[0] = 10;
 345                 cx->vbi.start[1] = 273;
 346         } else {        /* PAL/SECAM */
 347                 cx->vbi.count = 18;
 348                 cx->vbi.start[0] = 6;
 349                 cx->vbi.start[1] = 318;
 350         }
 351
 352         /* setup VBI registers */
 353         cx18_av_cmd(cx, VIDIOC_S_FMT, &cx->vbi.in);
 354
 355         /* determine number of lines and total number of VBI bytes.
 356            A raw line takes 1443 bytes: 2 * 720 + 4 byte frame header - 1
 357            The '- 1' byte is probably an unused U or V byte. Or something...
 358            A sliced line takes 51 bytes: 4 byte frame header, 4 byte internal
 359            header, 42 data bytes + checksum (to be confirmed) */
 360         if (raw) {
 361                 lines = cx->vbi.count * 2;
 362         } else {
 363                 lines = cx->is_60hz ? 24 : 38;
 364                 if (cx->is_60hz)
 365                         lines += 2;
 366         }
 367
 368         cx->vbi.enc_size = lines *
 369                 (raw ? cx->vbi.raw_size : cx->vbi.sliced_size);
 370
 371         data[0] = s->handle;
 372         /* Lines per field */
 373         data[1] = (lines / 2) | ((lines / 2) << 16);
 374         /* bytes per line */
 375         data[2] = (raw ? cx->vbi.raw_size : cx->vbi.sliced_size);
 376         /* Every X number of frames a VBI interrupt arrives
 377            (frames as in 25 or 30 fps) */
 378         data[3] = 1;
 379         /* Setup VBI for the cx25840 digitizer */
 380         if (raw) {
 381                 data[4] = 0x20602060;
 382                 data[5] = 0x30703070;
 383         } else {
 384                 data[4] = 0xB0F0B0F0;
 385                 data[5] = 0xA0E0A0E0;
 386         }
 387
 388         CX18_DEBUG_INFO("Setup VBI h: %d lines %x bpl %d fr %d %x %x\n",
 389                         data[0], data[1], data[2], data[3], data[4], data[5]);
 390
 391         if (s->type == CX18_ENC_STREAM_TYPE_VBI)
 392                 cx18_api(cx, CX18_CPU_SET_RAW_VBI_PARAM, 6, data);
 393 }
 394
 395 int cx18_start_v4l2_encode_stream(struct cx18_stream *s)
 396 {
 397         u32 data[MAX_MB_ARGUMENTS];
 398         struct cx18 *cx = s->cx;
 399         struct list_head *p;
 400         int ts = 0;
 401         int captype = 0;
 402
 403         if (s->v4l2dev == NULL && s->dvb.enabled == 0)
 404                 return -EINVAL;
 405
 406         CX18_DEBUG_INFO("Start encoder stream %s\n", s->name);
 407
 408         switch (s->type) {
 409         case CX18_ENC_STREAM_TYPE_MPG:
 410                 captype = CAPTURE_CHANNEL_TYPE_MPEG;
 411                 cx->mpg_data_received = cx->vbi_data_inserted = 0;
 412                 cx->dualwatch_jiffies = jiffies;
 413                 cx->dualwatch_stereo_mode = cx->params.audio_properties & 0x300;
 414                 cx->search_pack_header = 0;
 415                 break;
 416
 417         case CX18_ENC_STREAM_TYPE_TS:
 418                 captype = CAPTURE_CHANNEL_TYPE_TS;
 419                 ts = 1;
 420                 break;
 421         case CX18_ENC_STREAM_TYPE_YUV:
 422                 captype = CAPTURE_CHANNEL_TYPE_YUV;
 423                 break;
 424         case CX18_ENC_STREAM_TYPE_PCM:
 425                 captype = CAPTURE_CHANNEL_TYPE_PCM;
 426                 break;
 427         case CX18_ENC_STREAM_TYPE_VBI:
 428                 captype = cx->vbi.sliced_in->service_set ?
 429                     CAPTURE_CHANNEL_TYPE_SLICED_VBI : CAPTURE_CHANNEL_TYPE_VBI;
 430                 cx->vbi.frame = 0;
 431                 cx->vbi.inserted_frame = 0;
 432                 memset(cx->vbi.sliced_mpeg_size,
 433                         0, sizeof(cx->vbi.sliced_mpeg_size));
 434                 break;
 435         default:
 436                 return -EINVAL;
 437         }
 438         s->buffers_stolen = 0;
 439
 440         /* mute/unmute video */
 441         cx18_vapi(cx, CX18_CPU_SET_VIDEO_MUTE, 2,
 442                   s->handle, !!test_bit(CX18_F_I_RADIO_USER, &cx->i_flags));
 443
 444         /* Clear Streamoff flags in case left from last capture */
 445         clear_bit(CX18_F_S_STREAMOFF, &s->s_flags);
 446
 447         cx18_vapi_result(cx, data, CX18_CREATE_TASK, 1, CPU_CMD_MASK_CAPTURE);
 448         s->handle = data[0];
 449         cx18_vapi(cx, CX18_CPU_SET_CHANNEL_TYPE, 2, s->handle, captype);
 450
 451         if (atomic_read(&cx->ana_capturing) == 0 && !ts) {
 452                 /* Stuff from Windows, we don't know what it is */
 453                 cx18_vapi(cx, CX18_CPU_SET_VER_CROP_LINE, 2, s->handle, 0);
 454                 cx18_vapi(cx, CX18_CPU_SET_MISC_PARAMETERS, 3, s->handle, 3, 1);
 455                 cx18_vapi(cx, CX18_CPU_SET_MISC_PARAMETERS, 3, s->handle, 8, 0);
 456                 cx18_vapi(cx, CX18_CPU_SET_MISC_PARAMETERS, 3, s->handle, 4, 1);
 457                 cx18_vapi(cx, CX18_CPU_SET_MISC_PARAMETERS, 2, s->handle, 12);
 458
 459                 cx18_vapi(cx, CX18_CPU_SET_CAPTURE_LINE_NO, 3,
 460                                s->handle, cx->digitizer, cx->digitizer);
 461
 462                 /* Setup VBI */
 463                 if (cx->v4l2_cap & V4L2_CAP_VBI_CAPTURE)
 464                         cx18_vbi_setup(s);
 465
 466                 /* assign program index info.
 467                    Mask 7: select I/P/B, Num_req: 400 max */
 468                 cx18_vapi_result(cx, data, CX18_CPU_SET_INDEXTABLE, 1, 0);
 469
 470                 /* Setup API for Stream */
 471                 cx2341x_update(cx, cx18_api_func, NULL, &cx->params);
 472         }
 473
 474         if (atomic_read(&cx->tot_capturing) == 0) {
 475                 clear_bit(CX18_F_I_EOS, &cx->i_flags);
 476                 write_reg(7, CX18_DSP0_INTERRUPT_MASK);
 477         }
 478
 479         cx18_vapi(cx, CX18_CPU_DE_SET_MDL_ACK, 3, s->handle,
 480                 (void __iomem *)&cx->scb->cpu_mdl_ack[s->type][0] - cx->enc_mem,
 481                 (void __iomem *)&cx->scb->cpu_mdl_ack[s->type][1] - cx->enc_mem);
 482
 483         list_for_each(p, &s->q_free.list) {
 484                 struct cx18_buffer *buf = list_entry(p, struct cx18_buffer, list);
 485
 486                 writel(buf->dma_handle, &cx->scb->cpu_mdl[buf->id].paddr);
 487                 writel(s->buf_size, &cx->scb->cpu_mdl[buf->id].length);
 488                 cx18_vapi(cx, CX18_CPU_DE_SET_MDL, 5, s->handle,
 489                         (void __iomem *)&cx->scb->cpu_mdl[buf->id] - cx->enc_mem,
 490                         1, buf->id, s->buf_size);
 491         }
 492         /* begin_capture */
 493         if (cx18_vapi(cx, CX18_CPU_CAPTURE_START, 1, s->handle)) {
 494                 CX18_DEBUG_WARN("Error starting capture!\n");
 495                 cx18_vapi(cx, CX18_DESTROY_TASK, 1, s->handle);
 496                 return -EINVAL;
 497         }
 498
 499         /* you're live! sit back and await interrupts :) */
 500         if (!ts)
 501                 atomic_inc(&cx->ana_capturing);
 502         atomic_inc(&cx->tot_capturing);
 503         return 0;
 504 }
 505
 506 void cx18_stop_all_captures(struct cx18 *cx)
 507 {
 508         int i;
 509
 510         for (i = CX18_MAX_STREAMS - 1; i >= 0; i--) {
 511                 struct cx18_stream *s = &cx->streams[i];
 512
 513                 if (s->v4l2dev == NULL && s->dvb.enabled == 0)
 514                         continue;
 515                 if (test_bit(CX18_F_S_STREAMING, &s->s_flags))
 516                         cx18_stop_v4l2_encode_stream(s, 0);
 517         }
 518 }
 519
 520 int cx18_stop_v4l2_encode_stream(struct cx18_stream *s, int gop_end)
 521 {
 522         struct cx18 *cx = s->cx;
 523         unsigned long then;
 524
 525         if (s->v4l2dev == NULL && s->dvb.enabled == 0)
 526                 return -EINVAL;
 527
 528         /* This function assumes that you are allowed to stop the capture
 529            and that we are actually capturing */
 530
 531         CX18_DEBUG_INFO("Stop Capture\n");
 532
 533         if (atomic_read(&cx->tot_capturing) == 0)
 534                 return 0;
 535
 536         if (s->type == CX18_ENC_STREAM_TYPE_MPG)
 537                 cx18_vapi(cx, CX18_CPU_CAPTURE_STOP, 2, s->handle, !gop_end);
 538         else
 539                 cx18_vapi(cx, CX18_CPU_CAPTURE_STOP, 1, s->handle);
 540
 541         then = jiffies;
 542
 543         if (s->type == CX18_ENC_STREAM_TYPE_MPG && gop_end) {
 544                 CX18_INFO("ignoring gop_end: not (yet?) supported by the firmware\n");
 545         }
 546
 547         if (s->type != CX18_ENC_STREAM_TYPE_TS)
 548                 atomic_dec(&cx->ana_capturing);
 549         atomic_dec(&cx->tot_capturing);
 550
 551         /* Clear capture and no-read bits */
 552         clear_bit(CX18_F_S_STREAMING, &s->s_flags);
 553
 554         cx18_vapi(cx, CX18_DESTROY_TASK, 1, s->handle);
 555         s->handle = 0xffffffff;
 556
 557         if (atomic_read(&cx->tot_capturing) > 0)
 558                 return 0;
 559
 560         write_reg(5, CX18_DSP0_INTERRUPT_MASK);
 561         wake_up(&s->waitq);
 562
 563         return 0;
 564 }
 565
 566 u32 cx18_find_handle(struct cx18 *cx)
 567 {
 568         int i;
 569
 570         /* find first available handle to be used for global settings */
 571         for (i = 0; i < CX18_MAX_STREAMS; i++) {
 572                 struct cx18_stream *s = &cx->streams[i];
 573
 574                 if (s->v4l2dev && s->handle)
 575                         return s->handle;
 576         }
 577         return 0;
 578 }