sound/core/oss/pcm_plugin.c

   1 /*
   2  *  PCM Plug-In shared (kernel/library) code
   3  *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
   4  *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
   5  *
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Library General Public License as
   9  *   published by the Free Software Foundation; either version 2 of
  10  *   the License, or (at your option) any later version.
  11  *
  12  *   This program is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU Library General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Library General Public
  18  *   License along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  20  *
  21  */
  22
  23 #if 0
  24 #define PLUGIN_DEBUG
  25 #endif
  26
  27 #include <linux/slab.h>
  28 #include <linux/time.h>
  29 #include <linux/vmalloc.h>
  30 #include <sound/core.h>
  31 #include <sound/pcm.h>
  32 #include <sound/pcm_params.h>
  33 #include "pcm_plugin.h"
  34
  35 #define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
  36 #define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
  37
  38 /*
  39  *  because some cards might have rates "very close", we ignore
  40  *  all "resampling" requests within +-5%
  41  */
  42 static int rate_match(unsigned int src_rate, unsigned int dst_rate)
  43 {
  44         unsigned int low = (src_rate * 95) / 100;
  45         unsigned int high = (src_rate * 105) / 100;
  46         return dst_rate >= low && dst_rate <= high;
  47 }
  48
  49 static int snd_pcm_plugin_alloc(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
  50 {
  51         struct snd_pcm_plugin_format *format;
  52         ssize_t width;
  53         size_t size;
  54         unsigned int channel;
  55         struct snd_pcm_plugin_channel *c;
  56
  57         if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK) {
  58                 format = &plugin->src_format;
  59         } else {
  60                 format = &plugin->dst_format;
  61         }
  62         if ((width = snd_pcm_format_physical_width(format->format)) < 0)
  63                 return width;
  64         size = frames * format->channels * width;
  65         snd_assert((size % 8) == 0, return -ENXIO);
  66         size /= 8;
  67         if (plugin->buf_frames < frames) {
  68                 vfree(plugin->buf);
  69                 plugin->buf = vmalloc(size);
  70                 plugin->buf_frames = frames;
  71         }
  72         if (!plugin->buf) {
  73                 plugin->buf_frames = 0;
  74                 return -ENOMEM;
  75         }
  76         c = plugin->buf_channels;
  77         if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
  78                 for (channel = 0; channel < format->channels; channel++, c++) {
  79                         c->frames = frames;
  80                         c->enabled = 1;
  81                         c->wanted = 0;
  82                         c->area.addr = plugin->buf;
  83                         c->area.first = channel * width;
  84                         c->area.step = format->channels * width;
  85                 }
  86         } else if (plugin->access == SNDRV_PCM_ACCESS_RW_NONINTERLEAVED) {
  87                 snd_assert((size % format->channels) == 0,);
  88                 size /= format->channels;
  89                 for (channel = 0; channel < format->channels; channel++, c++) {
  90                         c->frames = frames;
  91                         c->enabled = 1;
  92                         c->wanted = 0;
  93                         c->area.addr = plugin->buf + (channel * size);
  94                         c->area.first = 0;
  95                         c->area.step = width;
  96                 }
  97         } else
  98                 return -EINVAL;
  99         return 0;
 100 }
 101
 102 int snd_pcm_plug_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t frames)
 103 {
 104         int err;
 105         snd_assert(snd_pcm_plug_first(plug) != NULL, return -ENXIO);
 106         if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
 107                 struct snd_pcm_plugin *plugin = snd_pcm_plug_first(plug);
 108                 while (plugin->next) {
 109                         if (plugin->dst_frames)
 110                                 frames = plugin->dst_frames(plugin, frames);
 111                         snd_assert(frames > 0, return -ENXIO);
 112                         plugin = plugin->next;
 113                         err = snd_pcm_plugin_alloc(plugin, frames);
 114                         if (err < 0)
 115                                 return err;
 116                 }
 117         } else {
 118                 struct snd_pcm_plugin *plugin = snd_pcm_plug_last(plug);
 119                 while (plugin->prev) {
 120                         if (plugin->src_frames)
 121                                 frames = plugin->src_frames(plugin, frames);
 122                         snd_assert(frames > 0, return -ENXIO);
 123                         plugin = plugin->prev;
 124                         err = snd_pcm_plugin_alloc(plugin, frames);
 125                         if (err < 0)
 126                                 return err;
 127                 }
 128         }
 129         return 0;
 130 }
 131
 132
 133 snd_pcm_sframes_t snd_pcm_plugin_client_channels(struct snd_pcm_plugin *plugin,
 134                                        snd_pcm_uframes_t frames,
 135                                        struct snd_pcm_plugin_channel **channels)
 136 {
 137         *channels = plugin->buf_channels;
 138         return frames;
 139 }
 140
 141 int snd_pcm_plugin_build(struct snd_pcm_substream *plug,
 142                          const char *name,
 143                          struct snd_pcm_plugin_format *src_format,
 144                          struct snd_pcm_plugin_format *dst_format,
 145                          size_t extra,
 146                          struct snd_pcm_plugin **ret)
 147 {
 148         struct snd_pcm_plugin *plugin;
 149         unsigned int channels;
 150
 151         snd_assert(plug != NULL, return -ENXIO);
 152         snd_assert(src_format != NULL && dst_format != NULL, return -ENXIO);
 153         plugin = kzalloc(sizeof(*plugin) + extra, GFP_KERNEL);
 154         if (plugin == NULL)
 155                 return -ENOMEM;
 156         plugin->name = name;
 157         plugin->plug = plug;
 158         plugin->stream = snd_pcm_plug_stream(plug);
 159         plugin->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
 160         plugin->src_format = *src_format;
 161         plugin->src_width = snd_pcm_format_physical_width(src_format->format);
 162         snd_assert(plugin->src_width > 0, );
 163         plugin->dst_format = *dst_format;
 164         plugin->dst_width = snd_pcm_format_physical_width(dst_format->format);
 165         snd_assert(plugin->dst_width > 0, );
 166         if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK)
 167                 channels = src_format->channels;
 168         else
 169                 channels = dst_format->channels;
 170         plugin->buf_channels = kcalloc(channels, sizeof(*plugin->buf_channels), GFP_KERNEL);
 171         if (plugin->buf_channels == NULL) {
 172                 snd_pcm_plugin_free(plugin);
 173                 return -ENOMEM;
 174         }
 175         plugin->client_channels = snd_pcm_plugin_client_channels;
 176         *ret = plugin;
 177         return 0;
 178 }
 179
 180 int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin)
 181 {
 182         if (! plugin)
 183                 return 0;
 184         if (plugin->private_free)
 185                 plugin->private_free(plugin);
 186         kfree(plugin->buf_channels);
 187         vfree(plugin->buf);
 188         kfree(plugin);
 189         return 0;
 190 }
 191
 192 snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t drv_frames)
 193 {
 194         struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
 195         int stream = snd_pcm_plug_stream(plug);
 196
 197         snd_assert(plug != NULL, return -ENXIO);
 198         if (drv_frames == 0)
 199                 return 0;
 200         if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
 201                 plugin = snd_pcm_plug_last(plug);
 202                 while (plugin && drv_frames > 0) {
 203                         plugin_prev = plugin->prev;
 204                         if (plugin->src_frames)
 205                                 drv_frames = plugin->src_frames(plugin, drv_frames);
 206                         plugin = plugin_prev;
 207                 }
 208         } else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 209                 plugin = snd_pcm_plug_first(plug);
 210                 while (plugin && drv_frames > 0) {
 211                         plugin_next = plugin->next;
 212                         if (plugin->dst_frames)
 213                                 drv_frames = plugin->dst_frames(plugin, drv_frames);
 214                         plugin = plugin_next;
 215                 }
 216         } else
 217                 snd_BUG();
 218         return drv_frames;
 219 }
 220
 221 snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t clt_frames)
 222 {
 223         struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
 224         snd_pcm_sframes_t frames;
 225         int stream = snd_pcm_plug_stream(plug);
 226
 227         snd_assert(plug != NULL, return -ENXIO);
 228         if (clt_frames == 0)
 229                 return 0;
 230         frames = clt_frames;
 231         if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
 232                 plugin = snd_pcm_plug_first(plug);
 233                 while (plugin && frames > 0) {
 234                         plugin_next = plugin->next;
 235                         if (plugin->dst_frames) {
 236                                 frames = plugin->dst_frames(plugin, frames);
 237                                 if (frames < 0)
 238                                         return frames;
 239                         }
 240                         plugin = plugin_next;
 241                 }
 242         } else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
 243                 plugin = snd_pcm_plug_last(plug);
 244                 while (plugin) {
 245                         plugin_prev = plugin->prev;
 246                         if (plugin->src_frames) {
 247                                 frames = plugin->src_frames(plugin, frames);
 248                                 if (frames < 0)
 249                                         return frames;
 250                         }
 251                         plugin = plugin_prev;
 252                 }
 253         } else
 254                 snd_BUG();
 255         return frames;
 256 }
 257
 258 static int snd_pcm_plug_formats(struct snd_mask *mask, int format)
 259 {
 260         struct snd_mask formats = *mask;
 261         u64 linfmts = (SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 |
 262                        SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_S16_LE |
 263                        SNDRV_PCM_FMTBIT_U16_BE | SNDRV_PCM_FMTBIT_S16_BE |
 264                        SNDRV_PCM_FMTBIT_U24_LE | SNDRV_PCM_FMTBIT_S24_LE |
 265                        SNDRV_PCM_FMTBIT_U24_BE | SNDRV_PCM_FMTBIT_S24_BE |
 266                        SNDRV_PCM_FMTBIT_U24_3LE | SNDRV_PCM_FMTBIT_S24_3LE |
 267                        SNDRV_PCM_FMTBIT_U24_3BE | SNDRV_PCM_FMTBIT_S24_3BE |
 268                        SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_S32_LE |
 269                        SNDRV_PCM_FMTBIT_U32_BE | SNDRV_PCM_FMTBIT_S32_BE);
 270         snd_mask_set(&formats, SNDRV_PCM_FORMAT_MU_LAW);
 271
 272         if (formats.bits[0] & (u32)linfmts)
 273                 formats.bits[0] |= (u32)linfmts;
 274         if (formats.bits[1] & (u32)(linfmts >> 32))
 275                 formats.bits[1] |= (u32)(linfmts >> 32);
 276         return snd_mask_test(&formats, format);
 277 }
 278
 279 static int preferred_formats[] = {
 280         SNDRV_PCM_FORMAT_S16_LE,
 281         SNDRV_PCM_FORMAT_S16_BE,
 282         SNDRV_PCM_FORMAT_U16_LE,
 283         SNDRV_PCM_FORMAT_U16_BE,
 284         SNDRV_PCM_FORMAT_S24_3LE,
 285         SNDRV_PCM_FORMAT_S24_3BE,
 286         SNDRV_PCM_FORMAT_U24_3LE,
 287         SNDRV_PCM_FORMAT_U24_3BE,
 288         SNDRV_PCM_FORMAT_S24_LE,
 289         SNDRV_PCM_FORMAT_S24_BE,
 290         SNDRV_PCM_FORMAT_U24_LE,
 291         SNDRV_PCM_FORMAT_U24_BE,
 292         SNDRV_PCM_FORMAT_S32_LE,
 293         SNDRV_PCM_FORMAT_S32_BE,
 294         SNDRV_PCM_FORMAT_U32_LE,
 295         SNDRV_PCM_FORMAT_U32_BE,
 296         SNDRV_PCM_FORMAT_S8,
 297         SNDRV_PCM_FORMAT_U8
 298 };
 299
 300 int snd_pcm_plug_slave_format(int format, struct snd_mask *format_mask)
 301 {
 302         int i;
 303
 304         if (snd_mask_test(format_mask, format))
 305                 return format;
 306         if (! snd_pcm_plug_formats(format_mask, format))
 307                 return -EINVAL;
 308         if (snd_pcm_format_linear(format)) {
 309                 unsigned int width = snd_pcm_format_width(format);
 310                 int unsignd = snd_pcm_format_unsigned(format) > 0;
 311                 int big = snd_pcm_format_big_endian(format) > 0;
 312                 unsigned int badness, best = -1;
 313                 int best_format = -1;
 314                 for (i = 0; i < ARRAY_SIZE(preferred_formats); i++) {
 315                         int f = preferred_formats[i];
 316                         unsigned int w;
 317                         if (!snd_mask_test(format_mask, f))
 318                                 continue;
 319                         w = snd_pcm_format_width(f);
 320                         if (w >= width)
 321                                 badness = w - width;
 322                         else
 323                                 badness = width - w + 32;
 324                         badness += snd_pcm_format_unsigned(f) != unsignd;
 325                         badness += snd_pcm_format_big_endian(f) != big;
 326                         if (badness < best) {
 327                                 best_format = f;
 328                                 best = badness;
 329                         }
 330                 }
 331                 return best_format >= 0 ? best_format : -EINVAL;
 332         } else {
 333                 switch (format) {
 334                 case SNDRV_PCM_FORMAT_MU_LAW:
 335                         for (i = 0; i < ARRAY_SIZE(preferred_formats); ++i) {
 336                                 int format1 = preferred_formats[i];
 337                                 if (snd_mask_test(format_mask, format1))
 338                                         return format1;
 339                         }
 340                 default:
 341                         return -EINVAL;
 342                 }
 343         }
 344 }
 345
 346 int snd_pcm_plug_format_plugins(struct snd_pcm_substream *plug,
 347                                 struct snd_pcm_hw_params *params,
 348                                 struct snd_pcm_hw_params *slave_params)
 349 {
 350         struct snd_pcm_plugin_format tmpformat;
 351         struct snd_pcm_plugin_format dstformat;
 352         struct snd_pcm_plugin_format srcformat;
 353         int src_access, dst_access;
 354         struct snd_pcm_plugin *plugin = NULL;
 355         int err;
 356         int stream = snd_pcm_plug_stream(plug);
 357         int slave_interleaved = (params_channels(slave_params) == 1 ||
 358                                  params_access(slave_params) == SNDRV_PCM_ACCESS_RW_INTERLEAVED);
 359
 360         switch (stream) {
 361         case SNDRV_PCM_STREAM_PLAYBACK:
 362                 dstformat.format = params_format(slave_params);
 363                 dstformat.rate = params_rate(slave_params);
 364                 dstformat.channels = params_channels(slave_params);
 365                 srcformat.format = params_format(params);
 366                 srcformat.rate = params_rate(params);
 367                 srcformat.channels = params_channels(params);
 368                 src_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
 369                 dst_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
 370                                                   SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
 371                 break;
 372         case SNDRV_PCM_STREAM_CAPTURE:
 373                 dstformat.format = params_format(params);
 374                 dstformat.rate = params_rate(params);
 375                 dstformat.channels = params_channels(params);
 376                 srcformat.format = params_format(slave_params);
 377                 srcformat.rate = params_rate(slave_params);
 378                 srcformat.channels = params_channels(slave_params);
 379                 src_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
 380                                                   SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
 381                 dst_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
 382                 break;
 383         default:
 384                 snd_BUG();
 385                 return -EINVAL;
 386         }
 387         tmpformat = srcformat;
 388
 389         pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
 390                  srcformat.format,
 391                  srcformat.rate,
 392                  srcformat.channels);
 393         pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
 394                  dstformat.format,
 395                  dstformat.rate,
 396                  dstformat.channels);
 397
 398         /* Format change (linearization) */
 399         if (! rate_match(srcformat.rate, dstformat.rate) &&
 400             ! snd_pcm_format_linear(srcformat.format)) {
 401                 if (srcformat.format != SNDRV_PCM_FORMAT_MU_LAW)
 402                         return -EINVAL;
 403                 tmpformat.format = SNDRV_PCM_FORMAT_S16;
 404                 err = snd_pcm_plugin_build_mulaw(plug,
 405                                                  &srcformat, &tmpformat,
 406                                                  &plugin);
 407                 if (err < 0)
 408                         return err;
 409                 err = snd_pcm_plugin_append(plugin);
 410                 if (err < 0) {
 411                         snd_pcm_plugin_free(plugin);
 412                         return err;
 413                 }
 414                 srcformat = tmpformat;
 415                 src_access = dst_access;
 416         }
 417
 418         /* channels reduction */
 419         if (srcformat.channels > dstformat.channels) {
 420                 tmpformat.channels = dstformat.channels;
 421                 err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
 422                 pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
 423                 if (err < 0)
 424                         return err;
 425                 err = snd_pcm_plugin_append(plugin);
 426                 if (err < 0) {
 427                         snd_pcm_plugin_free(plugin);
 428                         return err;
 429                 }
 430                 srcformat = tmpformat;
 431                 src_access = dst_access;
 432         }
 433
 434         /* rate resampling */
 435         if (!rate_match(srcformat.rate, dstformat.rate)) {
 436                 if (srcformat.format != SNDRV_PCM_FORMAT_S16) {
 437                         /* convert to S16 for resampling */
 438                         tmpformat.format = SNDRV_PCM_FORMAT_S16;
 439                         err = snd_pcm_plugin_build_linear(plug,
 440                                                           &srcformat, &tmpformat,
 441                                                           &plugin);
 442                         if (err < 0)
 443                                 return err;
 444                         err = snd_pcm_plugin_append(plugin);
 445                         if (err < 0) {
 446                                 snd_pcm_plugin_free(plugin);
 447                                 return err;
 448                         }
 449                         srcformat = tmpformat;
 450                         src_access = dst_access;
 451                 }
 452                 tmpformat.rate = dstformat.rate;
 453                 err = snd_pcm_plugin_build_rate(plug,
 454                                                 &srcformat, &tmpformat,
 455                                                 &plugin);
 456                 pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat.rate, tmpformat.rate, err);
 457                 if (err < 0)
 458                         return err;
 459                 err = snd_pcm_plugin_append(plugin);
 460                 if (err < 0) {
 461                         snd_pcm_plugin_free(plugin);
 462                         return err;
 463                 }
 464                 srcformat = tmpformat;
 465                 src_access = dst_access;
 466         }
 467
 468         /* format change */
 469         if (srcformat.format != dstformat.format) {
 470                 tmpformat.format = dstformat.format;
 471                 if (srcformat.format == SNDRV_PCM_FORMAT_MU_LAW ||
 472                     tmpformat.format == SNDRV_PCM_FORMAT_MU_LAW) {
 473                         err = snd_pcm_plugin_build_mulaw(plug,
 474                                                          &srcformat, &tmpformat,
 475                                                          &plugin);
 476                 }
 477                 else if (snd_pcm_format_linear(srcformat.format) &&
 478                          snd_pcm_format_linear(tmpformat.format)) {
 479                         err = snd_pcm_plugin_build_linear(plug,
 480                                                           &srcformat, &tmpformat,
 481                                                           &plugin);
 482                 }
 483                 else
 484                         return -EINVAL;
 485                 pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat.format, tmpformat.format, err);
 486                 if (err < 0)
 487                         return err;
 488                 err = snd_pcm_plugin_append(plugin);
 489                 if (err < 0) {
 490                         snd_pcm_plugin_free(plugin);
 491                         return err;
 492                 }
 493                 srcformat = tmpformat;
 494                 src_access = dst_access;
 495         }
 496
 497         /* channels extension */
 498         if (srcformat.channels < dstformat.channels) {
 499                 tmpformat.channels = dstformat.channels;
 500                 err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
 501                 pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
 502                 if (err < 0)
 503                         return err;
 504                 err = snd_pcm_plugin_append(plugin);
 505                 if (err < 0) {
 506                         snd_pcm_plugin_free(plugin);
 507                         return err;
 508                 }
 509                 srcformat = tmpformat;
 510                 src_access = dst_access;
 511         }
 512
 513         /* de-interleave */
 514         if (src_access != dst_access) {
 515                 err = snd_pcm_plugin_build_copy(plug,
 516                                                 &srcformat,
 517                                                 &tmpformat,
 518                                                 &plugin);
 519                 pdprintf("interleave change (copy: returns %i)\n", err);
 520                 if (err < 0)
 521                         return err;
 522                 err = snd_pcm_plugin_append(plugin);
 523                 if (err < 0) {
 524                         snd_pcm_plugin_free(plugin);
 525                         return err;
 526                 }
 527         }
 528
 529         return 0;
 530 }
 531
 532 snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(struct snd_pcm_substream *plug,
 533                                          char *buf,
 534                                          snd_pcm_uframes_t count,
 535                                          struct snd_pcm_plugin_channel **channels)
 536 {
 537         struct snd_pcm_plugin *plugin;
 538         struct snd_pcm_plugin_channel *v;
 539         struct snd_pcm_plugin_format *format;
 540         int width, nchannels, channel;
 541         int stream = snd_pcm_plug_stream(plug);
 542
 543         snd_assert(buf != NULL, return -ENXIO);
 544         if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
 545                 plugin = snd_pcm_plug_first(plug);
 546                 format = &plugin->src_format;
 547         } else {
 548                 plugin = snd_pcm_plug_last(plug);
 549                 format = &plugin->dst_format;
 550         }
 551         v = plugin->buf_channels;
 552         *channels = v;
 553         if ((width = snd_pcm_format_physical_width(format->format)) < 0)
 554                 return width;
 555         nchannels = format->channels;
 556         snd_assert(plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED || format->channels <= 1, return -ENXIO);
 557         for (channel = 0; channel < nchannels; channel++, v++) {
 558                 v->frames = count;
 559                 v->enabled = 1;
 560                 v->wanted = (stream == SNDRV_PCM_STREAM_CAPTURE);
 561                 v->area.addr = buf;
 562                 v->area.first = channel * width;
 563                 v->area.step = nchannels * width;
 564         }
 565         return count;
 566 }
 567
 568 snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *plug, struct snd_pcm_plugin_channel *src_channels, snd_pcm_uframes_t size)
 569 {
 570         struct snd_pcm_plugin *plugin, *next;
 571         struct snd_pcm_plugin_channel *dst_channels;
 572         int err;
 573         snd_pcm_sframes_t frames = size;
 574
 575         plugin = snd_pcm_plug_first(plug);
 576         while (plugin && frames > 0) {
 577                 if ((next = plugin->next) != NULL) {
 578                         snd_pcm_sframes_t frames1 = frames;
 579                         if (plugin->dst_frames)
 580                                 frames1 = plugin->dst_frames(plugin, frames);
 581                         if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
 582                                 return err;
 583                         }
 584                         if (err != frames1) {
 585                                 frames = err;
 586                                 if (plugin->src_frames)
 587                                         frames = plugin->src_frames(plugin, frames1);
 588                         }
 589                 } else
 590                         dst_channels = NULL;
 591                 pdprintf("write plugin: %s, %li\n", plugin->name, frames);
 592                 if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
 593                         return frames;
 594                 src_channels = dst_channels;
 595                 plugin = next;
 596         }
 597         return snd_pcm_plug_client_size(plug, frames);
 598 }
 599
 600 snd_pcm_sframes_t snd_pcm_plug_read_transfer(struct snd_pcm_substream *plug, struct snd_pcm_plugin_channel *dst_channels_final, snd_pcm_uframes_t size)
 601 {
 602         struct snd_pcm_plugin *plugin, *next;
 603         struct snd_pcm_plugin_channel *src_channels, *dst_channels;
 604         snd_pcm_sframes_t frames = size;
 605         int err;
 606
 607         frames = snd_pcm_plug_slave_size(plug, frames);
 608         if (frames < 0)
 609                 return frames;
 610
 611         src_channels = NULL;
 612         plugin = snd_pcm_plug_first(plug);
 613         while (plugin && frames > 0) {
 614                 if ((next = plugin->next) != NULL) {
 615                         if ((err = plugin->client_channels(plugin, frames, &dst_channels)) < 0) {
 616                                 return err;
 617                         }
 618                         frames = err;
 619                 } else {
 620                         dst_channels = dst_channels_final;
 621                 }
 622                 pdprintf("read plugin: %s, %li\n", plugin->name, frames);
 623                 if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
 624                         return frames;
 625                 plugin = next;
 626                 src_channels = dst_channels;
 627         }
 628         return frames;
 629 }
 630
 631 int snd_pcm_area_silence(const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
 632                          size_t samples, int format)
 633 {
 634         /* FIXME: sub byte resolution and odd dst_offset */
 635         unsigned char *dst;
 636         unsigned int dst_step;
 637         int width;
 638         const unsigned char *silence;
 639         if (!dst_area->addr)
 640                 return 0;
 641         dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
 642         width = snd_pcm_format_physical_width(format);
 643         if (width <= 0)
 644                 return -EINVAL;
 645         if (dst_area->step == (unsigned int) width && width >= 8)
 646                 return snd_pcm_format_set_silence(format, dst, samples);
 647         silence = snd_pcm_format_silence_64(format);
 648         if (! silence)
 649                 return -EINVAL;
 650         dst_step = dst_area->step / 8;
 651         if (width == 4) {
 652                 /* Ima ADPCM */
 653                 int dstbit = dst_area->first % 8;
 654                 int dstbit_step = dst_area->step % 8;
 655                 while (samples-- > 0) {
 656                         if (dstbit)
 657                                 *dst &= 0xf0;
 658                         else
 659                                 *dst &= 0x0f;
 660                         dst += dst_step;
 661                         dstbit += dstbit_step;
 662                         if (dstbit == 8) {
 663                                 dst++;
 664                                 dstbit = 0;
 665                         }
 666                 }
 667         } else {
 668                 width /= 8;
 669                 while (samples-- > 0) {
 670                         memcpy(dst, silence, width);
 671                         dst += dst_step;
 672                 }
 673         }
 674         return 0;
 675 }
 676
 677 int snd_pcm_area_copy(const struct snd_pcm_channel_area *src_area, size_t src_offset,
 678                       const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
 679                       size_t samples, int format)
 680 {
 681         /* FIXME: sub byte resolution and odd dst_offset */
 682         char *src, *dst;
 683         int width;
 684         int src_step, dst_step;
 685         src = src_area->addr + (src_area->first + src_area->step * src_offset) / 8;
 686         if (!src_area->addr)
 687                 return snd_pcm_area_silence(dst_area, dst_offset, samples, format);
 688         dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
 689         if (!dst_area->addr)
 690                 return 0;
 691         width = snd_pcm_format_physical_width(format);
 692         if (width <= 0)
 693                 return -EINVAL;
 694         if (src_area->step == (unsigned int) width &&
 695             dst_area->step == (unsigned int) width && width >= 8) {
 696                 size_t bytes = samples * width / 8;
 697                 memcpy(dst, src, bytes);
 698                 return 0;
 699         }
 700         src_step = src_area->step / 8;
 701         dst_step = dst_area->step / 8;
 702         if (width == 4) {
 703                 /* Ima ADPCM */
 704                 int srcbit = src_area->first % 8;
 705                 int srcbit_step = src_area->step % 8;
 706                 int dstbit = dst_area->first % 8;
 707                 int dstbit_step = dst_area->step % 8;
 708                 while (samples-- > 0) {
 709                         unsigned char srcval;
 710                         if (srcbit)
 711                                 srcval = *src & 0x0f;
 712                         else
 713                                 srcval = (*src & 0xf0) >> 4;
 714                         if (dstbit)
 715                                 *dst = (*dst & 0xf0) | srcval;
 716                         else
 717                                 *dst = (*dst & 0x0f) | (srcval << 4);
 718                         src += src_step;
 719                         srcbit += srcbit_step;
 720                         if (srcbit == 8) {
 721                                 src++;
 722                                 srcbit = 0;
 723                         }
 724                         dst += dst_step;
 725                         dstbit += dstbit_step;
 726                         if (dstbit == 8) {
 727                                 dst++;
 728                                 dstbit = 0;
 729                         }
 730                 }
 731         } else {
 732                 width /= 8;
 733                 while (samples-- > 0) {
 734                         memcpy(dst, src, width);
 735                         src += src_step;
 736                         dst += dst_step;
 737                 }
 738         }
 739         return 0;
 740 }