sound/core/pcm_misc.c - kernel/common - Git at Google

 /*
  *  PCM Interface - misc routines
  *  Copyright (c) 1998 by Jaroslav Kysela <[email protected]>
  *
  *
  *   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 <linux/export.h>
 #include <sound/core.h>
 #include <sound/pcm.h>

 #include "pcm_local.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 const 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 = {},
 	},
 	[SNDRV_PCM_FORMAT_DSD_U8] = {
 		.width = 8, .phys = 8, .le = 1, .signd = 0,
 		.silence = { 0x69 },
 	},
 	[SNDRV_PCM_FORMAT_DSD_U16_LE] = {
 		.width = 16, .phys = 16, .le = 1, .signd = 0,
 		.silence = { 0x69, 0x69 },
 	},
 	[SNDRV_PCM_FORMAT_DSD_U32_LE] = {
 		.width = 32, .phys = 32, .le = 1, .signd = 0,
 		.silence = { 0x69, 0x69, 0x69, 0x69 },
 	},
 	[SNDRV_PCM_FORMAT_DSD_U16_BE] = {
 		.width = 16, .phys = 16, .le = 0, .signd = 0,
 		.silence = { 0x69, 0x69 },
 	},
 	[SNDRV_PCM_FORMAT_DSD_U32_BE] = {
 		.width = 32, .phys = 32, .le = 0, .signd = 0,
 		.silence = { 0x69, 0x69, 0x69, 0x69 },
 	},
 	/* FIXME: the following two 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_S20_LE] = {
 		.width = 20, .phys = 32, .le = 1, .signd = 1,
 		.silence = {},
 	},
 	[SNDRV_PCM_FORMAT_S20_BE] = {
 		.width = 20, .phys = 32, .le = 0, .signd = 1,
 		.silence = {},
 	},
 	[SNDRV_PCM_FORMAT_U20_LE] = {
 		.width = 20, .phys = 32, .le = 1, .signd = 0,
 		.silence = { 0x00, 0x00, 0x08, 0x00 },
 	},
 	[SNDRV_PCM_FORMAT_U20_BE] = {
 		.width = 20, .phys = 32, .le = 0, .signd = 0,
 		.silence = { 0x00, 0x08, 0x00, 0x00 },
 	},
 	/* FIXME: the following format is not defined properly yet */
 	[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
  *
  * Return: 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
  *
  * Return: 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
  *
  * Return: 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
  *
  * Return: 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
  *
  * Return: 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
  *
  * Return: 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
  *
  * Return: 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
  *
  * Return: 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
  *
  * Return: 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.
  *
  * Return: 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;
 	const unsigned char *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.
  *
  * Return: 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
  *
  * Return: 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);

 /**
  * snd_pcm_rate_bit_to_rate - converts SNDRV_PCM_RATE_xxx bit to sample rate
  * @rate_bit: the rate bit to convert
  *
  * Return: The sample rate that corresponds to the given SNDRV_PCM_RATE_xxx flag
  * or 0 for an unknown rate bit.
  */
 unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit)
 {
 	unsigned int i;

 	for (i = 0; i < snd_pcm_known_rates.count; i++)
 		if ((1u << i) == rate_bit)
 			return snd_pcm_known_rates.list[i];
 	return 0;
 }
 EXPORT_SYMBOL(snd_pcm_rate_bit_to_rate);

 static unsigned int snd_pcm_rate_mask_sanitize(unsigned int rates)
 {
 	if (rates & SNDRV_PCM_RATE_CONTINUOUS)
 		return SNDRV_PCM_RATE_CONTINUOUS;
 	else if (rates & SNDRV_PCM_RATE_KNOT)
 		return SNDRV_PCM_RATE_KNOT;
 	return rates;
 }

 /**
  * snd_pcm_rate_mask_intersect - computes the intersection between two rate masks
  * @rates_a: The first rate mask
  * @rates_b: The second rate mask
  *
  * This function computes the rates that are supported by both rate masks passed
  * to the function. It will take care of the special handling of
  * SNDRV_PCM_RATE_CONTINUOUS and SNDRV_PCM_RATE_KNOT.
  *
  * Return: A rate mask containing the rates that are supported by both rates_a
  * and rates_b.
  */
 unsigned int snd_pcm_rate_mask_intersect(unsigned int rates_a,
 	unsigned int rates_b)
 {
 	rates_a = snd_pcm_rate_mask_sanitize(rates_a);
 	rates_b = snd_pcm_rate_mask_sanitize(rates_b);

 	if (rates_a & SNDRV_PCM_RATE_CONTINUOUS)
 		return rates_b;
 	else if (rates_b & SNDRV_PCM_RATE_CONTINUOUS)
 		return rates_a;
 	else if (rates_a & SNDRV_PCM_RATE_KNOT)
 		return rates_b;
 	else if (rates_b & SNDRV_PCM_RATE_KNOT)
 		return rates_a;
 	return rates_a & rates_b;
 }
 EXPORT_SYMBOL_GPL(snd_pcm_rate_mask_intersect);

 /**
  * snd_pcm_rate_range_to_bits - converts rate range to SNDRV_PCM_RATE_xxx bit
  * @rate_min: the minimum sample rate
  * @rate_max: the maximum sample rate
  *
  * This function has an implicit assumption: the rates in the given range have
  * only the pre-defined rates like 44100 or 16000.
  *
  * Return: The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate range,
  * or SNDRV_PCM_RATE_KNOT for an unknown range.
  */
 unsigned int snd_pcm_rate_range_to_bits(unsigned int rate_min,
 	unsigned int rate_max)
 {
 	unsigned int rates = 0;
 	int i;

 	for (i = 0; i < snd_pcm_known_rates.count; i++) {
 		if (snd_pcm_known_rates.list[i] >= rate_min
 			&& snd_pcm_known_rates.list[i] <= rate_max)
 			rates |= 1 << i;
 	}

 	if (!rates)
 		rates = SNDRV_PCM_RATE_KNOT;

 	return rates;
 }
 EXPORT_SYMBOL_GPL(snd_pcm_rate_range_to_bits);
	/*
	* PCM Interface - misc routines
	* Copyright (c) 1998 by Jaroslav Kysela <[email protected]>
	*
	*
	* 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 <linux/export.h>
	#include <sound/core.h>
	#include <sound/pcm.h>

	#include "pcm_local.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 const 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 = {},
	},
	[SNDRV_PCM_FORMAT_DSD_U8] = {
	.width = 8, .phys = 8, .le = 1, .signd = 0,
	.silence = { 0x69 },
	},
	[SNDRV_PCM_FORMAT_DSD_U16_LE] = {
	.width = 16, .phys = 16, .le = 1, .signd = 0,
	.silence = { 0x69, 0x69 },
	},
	[SNDRV_PCM_FORMAT_DSD_U32_LE] = {
	.width = 32, .phys = 32, .le = 1, .signd = 0,
	.silence = { 0x69, 0x69, 0x69, 0x69 },
	},
	[SNDRV_PCM_FORMAT_DSD_U16_BE] = {
	.width = 16, .phys = 16, .le = 0, .signd = 0,
	.silence = { 0x69, 0x69 },
	},
	[SNDRV_PCM_FORMAT_DSD_U32_BE] = {
	.width = 32, .phys = 32, .le = 0, .signd = 0,
	.silence = { 0x69, 0x69, 0x69, 0x69 },
	},
	/* FIXME: the following two 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_S20_LE] = {
	.width = 20, .phys = 32, .le = 1, .signd = 1,
	.silence = {},
	},
	[SNDRV_PCM_FORMAT_S20_BE] = {
	.width = 20, .phys = 32, .le = 0, .signd = 1,
	.silence = {},
	},
	[SNDRV_PCM_FORMAT_U20_LE] = {
	.width = 20, .phys = 32, .le = 1, .signd = 0,
	.silence = { 0x00, 0x00, 0x08, 0x00 },
	},
	[SNDRV_PCM_FORMAT_U20_BE] = {
	.width = 20, .phys = 32, .le = 0, .signd = 0,
	.silence = { 0x00, 0x08, 0x00, 0x00 },
	},
	/* FIXME: the following format is not defined properly yet */
	[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
	*
	* Return: 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
	*
	* Return: 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
	*
	* Return: 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
	*
	* Return: 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
	*
	* Return: 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
	*
	* Return: 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
	*
	* Return: 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
	*
	* Return: 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
	*
	* Return: 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.
	*
	* Return: 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;
	const unsigned char *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.
	*
	* Return: 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
	*
	* Return: 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);

	/**
	* snd_pcm_rate_bit_to_rate - converts SNDRV_PCM_RATE_xxx bit to sample rate
	* @rate_bit: the rate bit to convert
	*
	* Return: The sample rate that corresponds to the given SNDRV_PCM_RATE_xxx flag
	* or 0 for an unknown rate bit.
	*/
	unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit)
	{
	unsigned int i;

	for (i = 0; i < snd_pcm_known_rates.count; i++)
	if ((1u << i) == rate_bit)
	return snd_pcm_known_rates.list[i];
	return 0;
	}
	EXPORT_SYMBOL(snd_pcm_rate_bit_to_rate);

	static unsigned int snd_pcm_rate_mask_sanitize(unsigned int rates)
	{
	if (rates & SNDRV_PCM_RATE_CONTINUOUS)
	return SNDRV_PCM_RATE_CONTINUOUS;
	else if (rates & SNDRV_PCM_RATE_KNOT)
	return SNDRV_PCM_RATE_KNOT;
	return rates;
	}

	/**
	* snd_pcm_rate_mask_intersect - computes the intersection between two rate masks
	* @rates_a: The first rate mask
	* @rates_b: The second rate mask
	*
	* This function computes the rates that are supported by both rate masks passed
	* to the function. It will take care of the special handling of
	* SNDRV_PCM_RATE_CONTINUOUS and SNDRV_PCM_RATE_KNOT.
	*
	* Return: A rate mask containing the rates that are supported by both rates_a
	* and rates_b.
	*/
	unsigned int snd_pcm_rate_mask_intersect(unsigned int rates_a,
	unsigned int rates_b)
	{
	rates_a = snd_pcm_rate_mask_sanitize(rates_a);
	rates_b = snd_pcm_rate_mask_sanitize(rates_b);

	if (rates_a & SNDRV_PCM_RATE_CONTINUOUS)
	return rates_b;
	else if (rates_b & SNDRV_PCM_RATE_CONTINUOUS)
	return rates_a;
	else if (rates_a & SNDRV_PCM_RATE_KNOT)
	return rates_b;
	else if (rates_b & SNDRV_PCM_RATE_KNOT)
	return rates_a;
	return rates_a & rates_b;
	}
	EXPORT_SYMBOL_GPL(snd_pcm_rate_mask_intersect);

	/**
	* snd_pcm_rate_range_to_bits - converts rate range to SNDRV_PCM_RATE_xxx bit
	* @rate_min: the minimum sample rate
	* @rate_max: the maximum sample rate
	*
	* This function has an implicit assumption: the rates in the given range have
	* only the pre-defined rates like 44100 or 16000.
	*
	* Return: The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate range,
	* or SNDRV_PCM_RATE_KNOT for an unknown range.
	*/
	unsigned int snd_pcm_rate_range_to_bits(unsigned int rate_min,
	unsigned int rate_max)
	{
	unsigned int rates = 0;
	int i;

	for (i = 0; i < snd_pcm_known_rates.count; i++) {
	if (snd_pcm_known_rates.list[i] >= rate_min
	&& snd_pcm_known_rates.list[i] <= rate_max)
	rates \|= 1 << i;
	}

	if (!rates)
	rates = SNDRV_PCM_RATE_KNOT;

	return rates;
	}
	EXPORT_SYMBOL_GPL(snd_pcm_rate_range_to_bits);