LXR linux/sound/core/pcm

   1/*
   2 *  PCM Interface - misc routines
   3 *  Copyright (c) 1998 by Jaroslav Kysela <perex@perex.cz>
   4 *
   5 *
   6 *   This library is free software; you can redistribute it and/or modify
   7 *   it under the terms of the GNU Library General Public License as
   8 *   published by the Free Software Foundation; either version 2 of
   9 *   the License, or (at your option) any later version.
  10 *
  11 *   This program is distributed in the hope that it will be useful,
  12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *   GNU Library General Public License for more details.
  15 *
  16 *   You should have received a copy of the GNU Library General Public
  17 *   License along with this library; if not, write to the Free Software
  18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19 *
  20 */
  21  
  22#include <linux/time.h>
  23#include <sound/core.h>
  24#include <sound/pcm.h>
  25#define SND_PCM_FORMAT_UNKNOWN (-1)
  26
  27/* NOTE: "signed" prefix must be given below since the default char is
  28 *       unsigned on some architectures!
  29 */
  30struct pcm_format_data {
  31        unsigned char width;    /* bit width */
  32        unsigned char phys;     /* physical bit width */
  33        signed char le; /* 0 = big-endian, 1 = little-endian, -1 = others */
  34        signed char signd;      /* 0 = unsigned, 1 = signed, -1 = others */
  35        unsigned char silence[8];       /* silence data to fill */
  36};
  37
  38static struct pcm_format_data pcm_formats[SNDRV_PCM_FORMAT_LAST+1] = {
  39        [SNDRV_PCM_FORMAT_S8] = {
  40                .width = 8, .phys = 8, .le = -1, .signd = 1,
  41                .silence = {},
  42        },
  43        [SNDRV_PCM_FORMAT_U8] = {
  44                .width = 8, .phys = 8, .le = -1, .signd = 0,
  45                .silence = { 0x80 },
  46        },
  47        [SNDRV_PCM_FORMAT_S16_LE] = {
  48                .width = 16, .phys = 16, .le = 1, .signd = 1,
  49                .silence = {},
  50        },
  51        [SNDRV_PCM_FORMAT_S16_BE] = {
  52                .width = 16, .phys = 16, .le = 0, .signd = 1,
  53                .silence = {},
  54        },
  55        [SNDRV_PCM_FORMAT_U16_LE] = {
  56                .width = 16, .phys = 16, .le = 1, .signd = 0,
  57                .silence = { 0x00, 0x80 },
  58        },
  59        [SNDRV_PCM_FORMAT_U16_BE] = {
  60                .width = 16, .phys = 16, .le = 0, .signd = 0,
  61                .silence = { 0x80, 0x00 },
  62        },
  63        [SNDRV_PCM_FORMAT_S24_LE] = {
  64                .width = 24, .phys = 32, .le = 1, .signd = 1,
  65                .silence = {},
  66        },
  67        [SNDRV_PCM_FORMAT_S24_BE] = {
  68                .width = 24, .phys = 32, .le = 0, .signd = 1,
  69                .silence = {},
  70        },
  71        [SNDRV_PCM_FORMAT_U24_LE] = {
  72                .width = 24, .phys = 32, .le = 1, .signd = 0,
  73                .silence = { 0x00, 0x00, 0x80 },
  74        },
  75        [SNDRV_PCM_FORMAT_U24_BE] = {
  76                .width = 24, .phys = 32, .le = 0, .signd = 0,
  77                .silence = { 0x00, 0x80, 0x00, 0x00 },
  78        },
  79        [SNDRV_PCM_FORMAT_S32_LE] = {
  80                .width = 32, .phys = 32, .le = 1, .signd = 1,
  81                .silence = {},
  82        },
  83        [SNDRV_PCM_FORMAT_S32_BE] = {
  84                .width = 32, .phys = 32, .le = 0, .signd = 1,
  85                .silence = {},
  86        },
  87        [SNDRV_PCM_FORMAT_U32_LE] = {
  88                .width = 32, .phys = 32, .le = 1, .signd = 0,
  89                .silence = { 0x00, 0x00, 0x00, 0x80 },
  90        },
  91        [SNDRV_PCM_FORMAT_U32_BE] = {
  92                .width = 32, .phys = 32, .le = 0, .signd = 0,
  93                .silence = { 0x80, 0x00, 0x00, 0x00 },
  94        },
  95        [SNDRV_PCM_FORMAT_FLOAT_LE] = {
  96                .width = 32, .phys = 32, .le = 1, .signd = -1,
  97                .silence = {},
  98        },
  99        [SNDRV_PCM_FORMAT_FLOAT_BE] = {
 100                .width = 32, .phys = 32, .le = 0, .signd = -1,
 101                .silence = {},
 102        },
 103        [SNDRV_PCM_FORMAT_FLOAT64_LE] = {
 104                .width = 64, .phys = 64, .le = 1, .signd = -1,
 105                .silence = {},
 106        },
 107        [SNDRV_PCM_FORMAT_FLOAT64_BE] = {
 108                .width = 64, .phys = 64, .le = 0, .signd = -1,
 109                .silence = {},
 110        },
 111        [SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE] = {
 112                .width = 32, .phys = 32, .le = 1, .signd = -1,
 113                .silence = {},
 114        },
 115        [SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE] = {
 116                .width = 32, .phys = 32, .le = 0, .signd = -1,
 117                .silence = {},
 118        },
 119        [SNDRV_PCM_FORMAT_MU_LAW] = {
 120                .width = 8, .phys = 8, .le = -1, .signd = -1,
 121                .silence = { 0x7f },
 122        },
 123        [SNDRV_PCM_FORMAT_A_LAW] = {
 124                .width = 8, .phys = 8, .le = -1, .signd = -1,
 125                .silence = { 0x55 },
 126        },
 127        [SNDRV_PCM_FORMAT_IMA_ADPCM] = {
 128                .width = 4, .phys = 4, .le = -1, .signd = -1,
 129                .silence = {},
 130        },
 131        /* FIXME: the following three formats are not defined properly yet */
 132        [SNDRV_PCM_FORMAT_MPEG] = {
 133                .le = -1, .signd = -1,
 134        },
 135        [SNDRV_PCM_FORMAT_GSM] = {
 136                .le = -1, .signd = -1,
 137        },
 138        [SNDRV_PCM_FORMAT_SPECIAL] = {
 139                .le = -1, .signd = -1,
 140        },
 141        [SNDRV_PCM_FORMAT_S24_3LE] = {
 142                .width = 24, .phys = 24, .le = 1, .signd = 1,
 143                .silence = {},
 144        },
 145        [SNDRV_PCM_FORMAT_S24_3BE] = {
 146                .width = 24, .phys = 24, .le = 0, .signd = 1,
 147                .silence = {},
 148        },
 149        [SNDRV_PCM_FORMAT_U24_3LE] = {
 150                .width = 24, .phys = 24, .le = 1, .signd = 0,
 151                .silence = { 0x00, 0x00, 0x80 },
 152        },
 153        [SNDRV_PCM_FORMAT_U24_3BE] = {
 154                .width = 24, .phys = 24, .le = 0, .signd = 0,
 155                .silence = { 0x80, 0x00, 0x00 },
 156        },
 157        [SNDRV_PCM_FORMAT_S20_3LE] = {
 158                .width = 20, .phys = 24, .le = 1, .signd = 1,
 159                .silence = {},
 160        },
 161        [SNDRV_PCM_FORMAT_S20_3BE] = {
 162                .width = 20, .phys = 24, .le = 0, .signd = 1,
 163                .silence = {},
 164        },
 165        [SNDRV_PCM_FORMAT_U20_3LE] = {
 166                .width = 20, .phys = 24, .le = 1, .signd = 0,
 167                .silence = { 0x00, 0x00, 0x08 },
 168        },
 169        [SNDRV_PCM_FORMAT_U20_3BE] = {
 170                .width = 20, .phys = 24, .le = 0, .signd = 0,
 171                .silence = { 0x08, 0x00, 0x00 },
 172        },
 173        [SNDRV_PCM_FORMAT_S18_3LE] = {
 174                .width = 18, .phys = 24, .le = 1, .signd = 1,
 175                .silence = {},
 176        },
 177        [SNDRV_PCM_FORMAT_S18_3BE] = {
 178                .width = 18, .phys = 24, .le = 0, .signd = 1,
 179                .silence = {},
 180        },
 181        [SNDRV_PCM_FORMAT_U18_3LE] = {
 182                .width = 18, .phys = 24, .le = 1, .signd = 0,
 183                .silence = { 0x00, 0x00, 0x02 },
 184        },
 185        [SNDRV_PCM_FORMAT_U18_3BE] = {
 186                .width = 18, .phys = 24, .le = 0, .signd = 0,
 187                .silence = { 0x02, 0x00, 0x00 },
 188        },
 189};
 190
 191
 192/**
 193 * snd_pcm_format_signed - Check the PCM format is signed linear
 194 * @format: the format to check
 195 *
 196 * Returns 1 if the given PCM format is signed linear, 0 if unsigned
 197 * linear, and a negative error code for non-linear formats.
 198 */
 199int snd_pcm_format_signed(snd_pcm_format_t format)
 200{
 201        int val;
 202        if (format < 0 || format > SNDRV_PCM_FORMAT_LAST)
 203                return -EINVAL;
 204        if ((val = pcm_formats[format].signd) < 0)
 205                return -EINVAL;
 206        return val;
 207}
 208
 209EXPORT_SYMBOL(snd_pcm_format_signed);
 210
 211/**
 212 * snd_pcm_format_unsigned - Check the PCM format is unsigned linear
 213 * @format: the format to check
 214 *
 215 * Returns 1 if the given PCM format is unsigned linear, 0 if signed
 216 * linear, and a negative error code for non-linear formats.
 217 */
 218int snd_pcm_format_unsigned(snd_pcm_format_t format)
 219{
 220        int val;
 221
 222        val = snd_pcm_format_signed(format);
 223        if (val < 0)
 224                return val;
 225        return !val;
 226}
 227
 228EXPORT_SYMBOL(snd_pcm_format_unsigned);
 229
 230/**
 231 * snd_pcm_format_linear - Check the PCM format is linear
 232 * @format: the format to check
 233 *
 234 * Returns 1 if the given PCM format is linear, 0 if not.
 235 */
 236int snd_pcm_format_linear(snd_pcm_format_t format)
 237{
 238        return snd_pcm_format_signed(format) >= 0;
 239}
 240
 241EXPORT_SYMBOL(snd_pcm_format_linear);
 242
 243/**
 244 * snd_pcm_format_little_endian - Check the PCM format is little-endian
 245 * @format: the format to check
 246 *
 247 * Returns 1 if the given PCM format is little-endian, 0 if
 248 * big-endian, or a negative error code if endian not specified.
 249 */
 250int snd_pcm_format_little_endian(snd_pcm_format_t format)
 251{
 252        int val;
 253        if (format < 0 || format > SNDRV_PCM_FORMAT_LAST)
 254                return -EINVAL;
 255        if ((val = pcm_formats[format].le) < 0)
 256                return -EINVAL;
 257        return val;
 258}
 259
 260EXPORT_SYMBOL(snd_pcm_format_little_endian);
 261
 262/**
 263 * snd_pcm_format_big_endian - Check the PCM format is big-endian
 264 * @format: the format to check
 265 *
 266 * Returns 1 if the given PCM format is big-endian, 0 if
 267 * little-endian, or a negative error code if endian not specified.
 268 */
 269int snd_pcm_format_big_endian(snd_pcm_format_t format)
 270{
 271        int val;
 272
 273        val = snd_pcm_format_little_endian(format);
 274        if (val < 0)
 275                return val;
 276        return !val;
 277}
 278
 279EXPORT_SYMBOL(snd_pcm_format_big_endian);
 280
 281/**
 282 * snd_pcm_format_width - return the bit-width of the format
 283 * @format: the format to check
 284 *
 285 * Returns the bit-width of the format, or a negative error code
 286 * if unknown format.
 287 */
 288int snd_pcm_format_width(snd_pcm_format_t format)
 289{
 290        int val;
 291        if (format < 0 || format > SNDRV_PCM_FORMAT_LAST)
 292                return -EINVAL;
 293        if ((val = pcm_formats[format].width) == 0)
 294                return -EINVAL;
 295        return val;
 296}
 297
 298EXPORT_SYMBOL(snd_pcm_format_width);
 299
 300/**
 301 * snd_pcm_format_physical_width - return the physical bit-width of the format
 302 * @format: the format to check
 303 *
 304 * Returns the physical bit-width of the format, or a negative error code
 305 * if unknown format.
 306 */
 307int snd_pcm_format_physical_width(snd_pcm_format_t format)
 308{
 309        int val;
 310        if (format < 0 || format > SNDRV_PCM_FORMAT_LAST)
 311                return -EINVAL;
 312        if ((val = pcm_formats[format].phys) == 0)
 313                return -EINVAL;
 314        return val;
 315}
 316
 317EXPORT_SYMBOL(snd_pcm_format_physical_width);
 318
 319/**
 320 * snd_pcm_format_size - return the byte size of samples on the given format
 321 * @format: the format to check
 322 * @samples: sampling rate
 323 *
 324 * Returns the byte size of the given samples for the format, or a
 325 * negative error code if unknown format.
 326 */
 327ssize_t snd_pcm_format_size(snd_pcm_format_t format, size_t samples)
 328{
 329        int phys_width = snd_pcm_format_physical_width(format);
 330        if (phys_width < 0)
 331                return -EINVAL;
 332        return samples * phys_width / 8;
 333}
 334
 335EXPORT_SYMBOL(snd_pcm_format_size);
 336
 337/**
 338 * snd_pcm_format_silence_64 - return the silent data in 8 bytes array
 339 * @format: the format to check
 340 *
 341 * Returns the format pattern to fill or NULL if error.
 342 */
 343const unsigned char *snd_pcm_format_silence_64(snd_pcm_format_t format)
 344{
 345        if (format < 0 || format > SNDRV_PCM_FORMAT_LAST)
 346                return NULL;
 347        if (! pcm_formats[format].phys)
 348                return NULL;
 349        return pcm_formats[format].silence;
 350}
 351
 352EXPORT_SYMBOL(snd_pcm_format_silence_64);
 353
 354/**
 355 * snd_pcm_format_set_silence - set the silence data on the buffer
 356 * @format: the PCM format
 357 * @data: the buffer pointer
 358 * @samples: the number of samples to set silence
 359 *
 360 * Sets the silence data on the buffer for the given samples.
 361 *
 362 * Returns zero if successful, or a negative error code on failure.
 363 */
 364int snd_pcm_format_set_silence(snd_pcm_format_t format, void *data, unsigned int samples)
 365{
 366        int width;
 367        unsigned char *dst, *pat;
 368
 369        if (format < 0 || format > SNDRV_PCM_FORMAT_LAST)
 370                return -EINVAL;
 371        if (samples == 0)
 372                return 0;
 373        width = pcm_formats[format].phys; /* physical width */
 374        pat = pcm_formats[format].silence;
 375        if (! width)
 376                return -EINVAL;
 377        /* signed or 1 byte data */
 378        if (pcm_formats[format].signd == 1 || width <= 8) {
 379                unsigned int bytes = samples * width / 8;
 380                memset(data, *pat, bytes);
 381                return 0;
 382        }
 383        /* non-zero samples, fill using a loop */
 384        width /= 8;
 385        dst = data;
 386#if 0
 387        while (samples--) {
 388                memcpy(dst, pat, width);
 389                dst += width;
 390        }
 391#else
 392        /* a bit optimization for constant width */
 393        switch (width) {
 394        case 2:
 395                while (samples--) {
 396                        memcpy(dst, pat, 2);
 397                        dst += 2;
 398                }
 399                break;
 400        case 3:
 401                while (samples--) {
 402                        memcpy(dst, pat, 3);
 403                        dst += 3;
 404                }
 405                break;
 406        case 4:
 407                while (samples--) {
 408                        memcpy(dst, pat, 4);
 409                        dst += 4;
 410                }
 411                break;
 412        case 8:
 413                while (samples--) {
 414                        memcpy(dst, pat, 8);
 415                        dst += 8;
 416                }
 417                break;
 418        }
 419#endif
 420        return 0;
 421}
 422
 423EXPORT_SYMBOL(snd_pcm_format_set_silence);
 424
 425/**
 426 * snd_pcm_limit_hw_rates - determine rate_min/rate_max fields
 427 * @runtime: the runtime instance
 428 *
 429 * Determines the rate_min and rate_max fields from the rates bits of
 430 * the given runtime->hw.
 431 *
 432 * Returns zero if successful.
 433 */
 434int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime)
 435{
 436        int i;
 437        for (i = 0; i < (int)snd_pcm_known_rates.count; i++) {
 438                if (runtime->hw.rates & (1 << i)) {
 439                        runtime->hw.rate_min = snd_pcm_known_rates.list[i];
 440                        break;
 441                }
 442        }
 443        for (i = (int)snd_pcm_known_rates.count - 1; i >= 0; i--) {
 444                if (runtime->hw.rates & (1 << i)) {
 445                        runtime->hw.rate_max = snd_pcm_known_rates.list[i];
 446                        break;
 447                }
 448        }
 449        return 0;
 450}
 451
 452EXPORT_SYMBOL(snd_pcm_limit_hw_rates);
 453
 454/**
 455 * snd_pcm_rate_to_rate_bit - converts sample rate to SNDRV_PCM_RATE_xxx bit
 456 * @rate: the sample rate to convert
 457 *
 458 * Returns the SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or
 459 * SNDRV_PCM_RATE_KNOT for an unknown rate.
 460 */
 461unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate)
 462{
 463        unsigned int i;
 464
 465        for (i = 0; i < snd_pcm_known_rates.count; i++)
 466                if (snd_pcm_known_rates.list[i] == rate)
 467                        return 1u << i;
 468        return SNDRV_PCM_RATE_KNOT;
 469}
 470EXPORT_SYMBOL(snd_pcm_rate_to_rate_bit);
 471