4a462ce084
Treat 32 bit sample width as if it was 24 bits when generating IEC958 channel status bits. On some platforms 24 sample width is problematic and to get full 24 bit precision a 32 bit format, using only the 24 most significant bits, may have to be used. Signed-off-by: Jyri Sarha <jsarha@ti.com> Reviewed-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Mark Brown <broonie@kernel.org>
126 lines
3.2 KiB
C
126 lines
3.2 KiB
C
/*
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* PCM DRM helpers
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/export.h>
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#include <linux/types.h>
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#include <sound/asoundef.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#include <sound/pcm_iec958.h>
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static int create_iec958_consumer(uint rate, uint sample_width,
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u8 *cs, size_t len)
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{
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unsigned int fs, ws;
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if (len < 4)
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return -EINVAL;
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switch (rate) {
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case 32000:
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fs = IEC958_AES3_CON_FS_32000;
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break;
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case 44100:
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fs = IEC958_AES3_CON_FS_44100;
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break;
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case 48000:
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fs = IEC958_AES3_CON_FS_48000;
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break;
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case 88200:
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fs = IEC958_AES3_CON_FS_88200;
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break;
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case 96000:
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fs = IEC958_AES3_CON_FS_96000;
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break;
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case 176400:
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fs = IEC958_AES3_CON_FS_176400;
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break;
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case 192000:
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fs = IEC958_AES3_CON_FS_192000;
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break;
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default:
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return -EINVAL;
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}
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if (len > 4) {
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switch (sample_width) {
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case 16:
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ws = IEC958_AES4_CON_WORDLEN_20_16;
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break;
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case 18:
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ws = IEC958_AES4_CON_WORDLEN_22_18;
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break;
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case 20:
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ws = IEC958_AES4_CON_WORDLEN_20_16 |
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IEC958_AES4_CON_MAX_WORDLEN_24;
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break;
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case 24:
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case 32: /* Assume 24-bit width for 32-bit samples. */
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ws = IEC958_AES4_CON_WORDLEN_24_20 |
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IEC958_AES4_CON_MAX_WORDLEN_24;
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break;
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default:
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return -EINVAL;
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}
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}
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memset(cs, 0, len);
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cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE;
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cs[1] = IEC958_AES1_CON_GENERAL;
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cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC;
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cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | fs;
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if (len > 4)
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cs[4] = ws;
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return len;
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}
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/**
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* snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
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* @runtime: pcm runtime structure with ->rate filled in
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* @cs: channel status buffer, at least four bytes
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* @len: length of channel status buffer
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*
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* Create the consumer format channel status data in @cs of maximum size
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* @len corresponding to the parameters of the PCM runtime @runtime.
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*
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* Drivers may wish to tweak the contents of the buffer after creation.
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*
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* Returns: length of buffer, or negative error code if something failed.
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*/
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int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
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size_t len)
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{
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return create_iec958_consumer(runtime->rate,
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snd_pcm_format_width(runtime->format),
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cs, len);
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}
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EXPORT_SYMBOL(snd_pcm_create_iec958_consumer);
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/**
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* snd_pcm_create_iec958_consumer_hw_params - create IEC958 channel status
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* @hw_params: the hw_params instance for extracting rate and sample format
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* @cs: channel status buffer, at least four bytes
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* @len: length of channel status buffer
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*
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* Create the consumer format channel status data in @cs of maximum size
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* @len corresponding to the parameters of the PCM runtime @runtime.
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*
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* Drivers may wish to tweak the contents of the buffer after creation.
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*
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* Returns: length of buffer, or negative error code if something failed.
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*/
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int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params,
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u8 *cs, size_t len)
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{
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return create_iec958_consumer(params_rate(params), params_width(params),
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cs, len);
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}
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EXPORT_SYMBOL(snd_pcm_create_iec958_consumer_hw_params);
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