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kernel/linux-rt-4.4.41/sound/core/pcm_iec958.c 3.25 KB
5113f6f70   김현기   kernel add
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  /*
   *  PCM DRM helpers
   *
   *   This program is free software; you can redistribute it and/or modify
   *   it under the terms of the GNU General Public License version 2 as
   *   published by the Free Software Foundation.
   */
  #include <linux/export.h>
  #include <linux/types.h>
  #include <sound/asoundef.h>
  #include <sound/pcm.h>
  #include <sound/pcm_params.h>
  #include <sound/pcm_iec958.h>
  
  static int create_iec958_consumer(uint rate, uint sample_width,
  				  u8 *cs, size_t len)
  {
  	unsigned int fs, ws;
  
  	if (len < 4)
  		return -EINVAL;
  
  	switch (rate) {
  	case 32000:
  		fs = IEC958_AES3_CON_FS_32000;
  		break;
  	case 44100:
  		fs = IEC958_AES3_CON_FS_44100;
  		break;
  	case 48000:
  		fs = IEC958_AES3_CON_FS_48000;
  		break;
  	case 88200:
  		fs = IEC958_AES3_CON_FS_88200;
  		break;
  	case 96000:
  		fs = IEC958_AES3_CON_FS_96000;
  		break;
  	case 176400:
  		fs = IEC958_AES3_CON_FS_176400;
  		break;
  	case 192000:
  		fs = IEC958_AES3_CON_FS_192000;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	if (len > 4) {
  		switch (sample_width) {
  		case 16:
  			ws = IEC958_AES4_CON_WORDLEN_20_16;
  			break;
  		case 18:
  			ws = IEC958_AES4_CON_WORDLEN_22_18;
  			break;
  		case 20:
  			ws = IEC958_AES4_CON_WORDLEN_20_16 |
  			     IEC958_AES4_CON_MAX_WORDLEN_24;
  			break;
  		case 24:
  		case 32: /* Assume 24-bit width for 32-bit samples. */
  			ws = IEC958_AES4_CON_WORDLEN_24_20 |
  			     IEC958_AES4_CON_MAX_WORDLEN_24;
  			break;
  
  		default:
  			return -EINVAL;
  		}
  	}
  
  	memset(cs, 0, len);
  
  	cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE;
  	cs[1] = IEC958_AES1_CON_GENERAL;
  	cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC;
  	cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | fs;
  
  	if (len > 4)
  		cs[4] = ws;
  
  	return len;
  }
  
  /**
   * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
   * @runtime: pcm runtime structure with ->rate filled in
   * @cs: channel status buffer, at least four bytes
   * @len: length of channel status buffer
   *
   * Create the consumer format channel status data in @cs of maximum size
   * @len corresponding to the parameters of the PCM runtime @runtime.
   *
   * Drivers may wish to tweak the contents of the buffer after creation.
   *
   * Returns: length of buffer, or negative error code if something failed.
   */
  int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
  	size_t len)
  {
  	return create_iec958_consumer(runtime->rate,
  				      snd_pcm_format_width(runtime->format),
  				      cs, len);
  }
  EXPORT_SYMBOL(snd_pcm_create_iec958_consumer);
  
  /**
   * snd_pcm_create_iec958_consumer_hw_params - create IEC958 channel status
   * @hw_params: the hw_params instance for extracting rate and sample format
   * @cs: channel status buffer, at least four bytes
   * @len: length of channel status buffer
   *
   * Create the consumer format channel status data in @cs of maximum size
   * @len corresponding to the parameters of the PCM runtime @runtime.
   *
   * Drivers may wish to tweak the contents of the buffer after creation.
   *
   * Returns: length of buffer, or negative error code if something failed.
   */
  int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params,
  					     u8 *cs, size_t len)
  {
  	return create_iec958_consumer(params_rate(params), params_width(params),
  				      cs, len);
  }
  EXPORT_SYMBOL(snd_pcm_create_iec958_consumer_hw_params);