- 根目录:
- sound
- core
- pcm_misc.c
/*
* PCM Interface - misc routines
* Copyright (c) 1998 by Jaroslav Kysela <perex@perex.cz>
*
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/time.h>
#include <sound/core.h>
#include <sound/pcm.h>
#define SND_PCM_FORMAT_UNKNOWN (-1)
/* NOTE: "signed" prefix must be given below since the default char is
* unsigned on some architectures!
*/
struct pcm_format_data {
unsigned char width; /* bit width */
unsigned char phys; /* physical bit width */
signed char le; /* 0 = big-endian, 1 = little-endian, -1 = others */
signed char signd; /* 0 = unsigned, 1 = signed, -1 = others */
unsigned char silence[8]; /* silence data to fill */
};
/* we do lots of calculations on snd_pcm_format_t; shut up sparse */
#define INT __force int
static struct pcm_format_data pcm_formats[(INT)SNDRV_PCM_FORMAT_LAST+1] = {
[SNDRV_PCM_FORMAT_S8] = {
.width = 8, .phys = 8, .le = -1, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_U8] = {
.width = 8, .phys = 8, .le = -1, .signd = 0,
.silence = { 0x80 },
},
[SNDRV_PCM_FORMAT_S16_LE] = {
.width = 16, .phys = 16, .le = 1, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_S16_BE] = {
.width = 16, .phys = 16, .le = 0, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_U16_LE] = {
.width = 16, .phys = 16, .le = 1, .signd = 0,
.silence = { 0x00, 0x80 },
},
[SNDRV_PCM_FORMAT_U16_BE] = {
.width = 16, .phys = 16, .le = 0, .signd = 0,
.silence = { 0x80, 0x00 },
},
[SNDRV_PCM_FORMAT_S24_LE] = {
.width = 24, .phys = 32, .le = 1, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_S24_BE] = {
.width = 24, .phys = 32, .le = 0, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_U24_LE] = {
.width = 24, .phys = 32, .le = 1, .signd = 0,
.silence = { 0x00, 0x00, 0x80 },
},
[SNDRV_PCM_FORMAT_U24_BE] = {
.width = 24, .phys = 32, .le = 0, .signd = 0,
.silence = { 0x00, 0x80, 0x00, 0x00 },
},
[SNDRV_PCM_FORMAT_S32_LE] = {
.width = 32, .phys = 32, .le = 1, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_S32_BE] = {
.width = 32, .phys = 32, .le = 0, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_U32_LE] = {
.width = 32, .phys = 32, .le = 1, .signd = 0,
.silence = { 0x00, 0x00, 0x00, 0x80 },
},
[SNDRV_PCM_FORMAT_U32_BE] = {
.width = 32, .phys = 32, .le = 0, .signd = 0,
.silence = { 0x80, 0x00, 0x00, 0x00 },
},
[SNDRV_PCM_FORMAT_FLOAT_LE] = {
.width = 32, .phys = 32, .le = 1, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_FLOAT_BE] = {
.width = 32, .phys = 32, .le = 0, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_FLOAT64_LE] = {
.width = 64, .phys = 64, .le = 1, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_FLOAT64_BE] = {
.width = 64, .phys = 64, .le = 0, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE] = {
.width = 32, .phys = 32, .le = 1, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE] = {
.width = 32, .phys = 32, .le = 0, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_MU_LAW] = {
.width = 8, .phys = 8, .le = -1, .signd = -1,
.silence = { 0x7f },
},
[SNDRV_PCM_FORMAT_A_LAW] = {
.width = 8, .phys = 8, .le = -1, .signd = -1,
.silence = { 0x55 },
},
[SNDRV_PCM_FORMAT_IMA_ADPCM] = {
.width = 4, .phys = 4, .le = -1, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_G723_24] = {
.width = 3, .phys = 3, .le = -1, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_G723_40] = {
.width = 5, .phys = 5, .le = -1, .signd = -1,
.silence = {},
},
/* FIXME: the following three formats are not defined properly yet */
[SNDRV_PCM_FORMAT_MPEG] = {
.le = -1, .signd = -1,
},
[SNDRV_PCM_FORMAT_GSM] = {
.le = -1, .signd = -1,
},
[SNDRV_PCM_FORMAT_SPECIAL] = {
.le = -1, .signd = -1,
},
[SNDRV_PCM_FORMAT_S24_3LE] = {
.width = 24, .phys = 24, .le = 1, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_S24_3BE] = {
.width = 24, .phys = 24, .le = 0, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_U24_3LE] = {
.width = 24, .phys = 24, .le = 1, .signd = 0,
.silence = { 0x00, 0x00, 0x80 },
},
[SNDRV_PCM_FORMAT_U24_3BE] = {
.width = 24, .phys = 24, .le = 0, .signd = 0,
.silence = { 0x80, 0x00, 0x00 },
},
[SNDRV_PCM_FORMAT_S20_3LE] = {
.width = 20, .phys = 24, .le = 1, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_S20_3BE] = {
.width = 20, .phys = 24, .le = 0, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_U20_3LE] = {
.width = 20, .phys = 24, .le = 1, .signd = 0,
.silence = { 0x00, 0x00, 0x08 },
},
[SNDRV_PCM_FORMAT_U20_3BE] = {
.width = 20, .phys = 24, .le = 0, .signd = 0,
.silence = { 0x08, 0x00, 0x00 },
},
[SNDRV_PCM_FORMAT_S18_3LE] = {
.width = 18, .phys = 24, .le = 1, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_S18_3BE] = {
.width = 18, .phys = 24, .le = 0, .signd = 1,
.silence = {},
},
[SNDRV_PCM_FORMAT_U18_3LE] = {
.width = 18, .phys = 24, .le = 1, .signd = 0,
.silence = { 0x00, 0x00, 0x02 },
},
[SNDRV_PCM_FORMAT_U18_3BE] = {
.width = 18, .phys = 24, .le = 0, .signd = 0,
.silence = { 0x02, 0x00, 0x00 },
},
[SNDRV_PCM_FORMAT_G723_24_1B] = {
.width = 3, .phys = 8, .le = -1, .signd = -1,
.silence = {},
},
[SNDRV_PCM_FORMAT_G723_40_1B] = {
.width = 5, .phys = 8, .le = -1, .signd = -1,
.silence = {},
},
};
/**
* snd_pcm_format_signed - Check the PCM format is signed linear
* @format: the format to check
*
* Returns 1 if the given PCM format is signed linear, 0 if unsigned
* linear, and a negative error code for non-linear formats.
*/
int snd_pcm_format_signed(snd_pcm_format_t format)
{
int val;
if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
return -EINVAL;
if ((val = pcm_formats[(INT)format].signd) < 0)
return -EINVAL;
return val;
}
EXPORT_SYMBOL(snd_pcm_format_signed);
/**
* snd_pcm_format_unsigned - Check the PCM format is unsigned linear
* @format: the format to check
*
* Returns 1 if the given PCM format is unsigned linear, 0 if signed
* linear, and a negative error code for non-linear formats.
*/
int snd_pcm_format_unsigned(snd_pcm_format_t format)
{
int val;
val = snd_pcm_format_signed(format);
if (val < 0)
return val;
return !val;
}
EXPORT_SYMBOL(snd_pcm_format_unsigned);
/**
* snd_pcm_format_linear - Check the PCM format is linear
* @format: the format to check
*
* Returns 1 if the given PCM format is linear, 0 if not.
*/
int snd_pcm_format_linear(snd_pcm_format_t format)
{
return snd_pcm_format_signed(format) >= 0;
}
EXPORT_SYMBOL(snd_pcm_format_linear);
/**
* snd_pcm_format_little_endian - Check the PCM format is little-endian
* @format: the format to check
*
* Returns 1 if the given PCM format is little-endian, 0 if
* big-endian, or a negative error code if endian not specified.
*/
int snd_pcm_format_little_endian(snd_pcm_format_t format)
{
int val;
if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
return -EINVAL;
if ((val = pcm_formats[(INT)format].le) < 0)
return -EINVAL;
return val;
}
EXPORT_SYMBOL(snd_pcm_format_little_endian);
/**
* snd_pcm_format_big_endian - Check the PCM format is big-endian
* @format: the format to check
*
* Returns 1 if the given PCM format is big-endian, 0 if
* little-endian, or a negative error code if endian not specified.
*/
int snd_pcm_format_big_endian(snd_pcm_format_t format)
{
int val;
val = snd_pcm_format_little_endian(format);
if (val < 0)
return val;
return !val;
}
EXPORT_SYMBOL(snd_pcm_format_big_endian);
/**
* snd_pcm_format_width - return the bit-width of the format
* @format: the format to check
*
* Returns the bit-width of the format, or a negative error code
* if unknown format.
*/
int snd_pcm_format_width(snd_pcm_format_t format)
{
int val;
if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
return -EINVAL;
if ((val = pcm_formats[(INT)format].width) == 0)
return -EINVAL;
return val;
}
EXPORT_SYMBOL(snd_pcm_format_width);
/**
* snd_pcm_format_physical_width - return the physical bit-width of the format
* @format: the format to check
*
* Returns the physical bit-width of the format, or a negative error code
* if unknown format.
*/
int snd_pcm_format_physical_width(snd_pcm_format_t format)
{
int val;
if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
return -EINVAL;
if ((val = pcm_formats[(INT)format].phys) == 0)
return -EINVAL;
return val;
}
EXPORT_SYMBOL(snd_pcm_format_physical_width);
/**
* snd_pcm_format_size - return the byte size of samples on the given format
* @format: the format to check
* @samples: sampling rate
*
* Returns the byte size of the given samples for the format, or a
* negative error code if unknown format.
*/
ssize_t snd_pcm_format_size(snd_pcm_format_t format, size_t samples)
{
int phys_width = snd_pcm_format_physical_width(format);
if (phys_width < 0)
return -EINVAL;
return samples * phys_width / 8;
}
EXPORT_SYMBOL(snd_pcm_format_size);
/**
* snd_pcm_format_silence_64 - return the silent data in 8 bytes array
* @format: the format to check
*
* Returns the format pattern to fill or NULL if error.
*/
const unsigned char *snd_pcm_format_silence_64(snd_pcm_format_t format)
{
if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
return NULL;
if (! pcm_formats[(INT)format].phys)
return NULL;
return pcm_formats[(INT)format].silence;
}
EXPORT_SYMBOL(snd_pcm_format_silence_64);
/**
* snd_pcm_format_set_silence - set the silence data on the buffer
* @format: the PCM format
* @data: the buffer pointer
* @samples: the number of samples to set silence
*
* Sets the silence data on the buffer for the given samples.
*
* Returns zero if successful, or a negative error code on failure.
*/
int snd_pcm_format_set_silence(snd_pcm_format_t format, void *data, unsigned int samples)
{
int width;
unsigned char *dst, *pat;
if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
return -EINVAL;
if (samples == 0)
return 0;
width = pcm_formats[(INT)format].phys; /* physical width */
pat = pcm_formats[(INT)format].silence;
if (! width)
return -EINVAL;
/* signed or 1 byte data */
if (pcm_formats[(INT)format].signd == 1 || width <= 8) {
unsigned int bytes = samples * width / 8;
memset(data, *pat, bytes);
return 0;
}
/* non-zero samples, fill using a loop */
width /= 8;
dst = data;
#if 0
while (samples--) {
memcpy(dst, pat, width);
dst += width;
}
#else
/* a bit optimization for constant width */
switch (width) {
case 2:
while (samples--) {
memcpy(dst, pat, 2);
dst += 2;
}
break;
case 3:
while (samples--) {
memcpy(dst, pat, 3);
dst += 3;
}
break;
case 4:
while (samples--) {
memcpy(dst, pat, 4);
dst += 4;
}
break;
case 8:
while (samples--) {
memcpy(dst, pat, 8);
dst += 8;
}
break;
}
#endif
return 0;
}
EXPORT_SYMBOL(snd_pcm_format_set_silence);
/**
* snd_pcm_limit_hw_rates - determine rate_min/rate_max fields
* @runtime: the runtime instance
*
* Determines the rate_min and rate_max fields from the rates bits of
* the given runtime->hw.
*
* Returns zero if successful.
*/
int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime)
{
int i;
for (i = 0; i < (int)snd_pcm_known_rates.count; i++) {
if (runtime->hw.rates & (1 << i)) {
runtime->hw.rate_min = snd_pcm_known_rates.list[i];
break;
}
}
for (i = (int)snd_pcm_known_rates.count - 1; i >= 0; i--) {
if (runtime->hw.rates & (1 << i)) {
runtime->hw.rate_max = snd_pcm_known_rates.list[i];
break;
}
}
return 0;
}
EXPORT_SYMBOL(snd_pcm_limit_hw_rates);
/**
* snd_pcm_rate_to_rate_bit - converts sample rate to SNDRV_PCM_RATE_xxx bit
* @rate: the sample rate to convert
*
* Returns the SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or
* SNDRV_PCM_RATE_KNOT for an unknown rate.
*/
unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate)
{
unsigned int i;
for (i = 0; i < snd_pcm_known_rates.count; i++)
if (snd_pcm_known_rates.list[i] == rate)
return 1u << i;
return SNDRV_PCM_RATE_KNOT;
}
EXPORT_SYMBOL(snd_pcm_rate_to_rate_bit);