sound/core/pcm_iec958.c

   1 /*
   2  *  PCM DRM helpers
   3  *
   4  *   This program is free software; you can redistribute it and/or modify
   5  *   it under the terms of the GNU General Public License version 2 as
   6  *   published by the Free Software Foundation.
   7  */
   8 #include <linux/export.h>
   9 #include <linux/types.h>
  10 #include <sound/asoundef.h>
  11 #include <sound/pcm.h>
  12 #include <sound/pcm_params.h>
  13 #include <sound/pcm_iec958.h>
  14
  15 static int create_iec958_consumer(uint rate, uint sample_width,
  16                                   u8 *cs, size_t len)
  17 {
  18         unsigned int fs, ws;
  19
  20         if (len < 4)
  21                 return -EINVAL;
  22
  23         switch (rate) {
  24         case 32000:
  25                 fs = IEC958_AES3_CON_FS_32000;
  26                 break;
  27         case 44100:
  28                 fs = IEC958_AES3_CON_FS_44100;
  29                 break;
  30         case 48000:
  31                 fs = IEC958_AES3_CON_FS_48000;
  32                 break;
  33         case 88200:
  34                 fs = IEC958_AES3_CON_FS_88200;
  35                 break;
  36         case 96000:
  37                 fs = IEC958_AES3_CON_FS_96000;
  38                 break;
  39         case 176400:
  40                 fs = IEC958_AES3_CON_FS_176400;
  41                 break;
  42         case 192000:
  43                 fs = IEC958_AES3_CON_FS_192000;
  44                 break;
  45         default:
  46                 return -EINVAL;
  47         }
  48
  49         if (len > 4) {
  50                 switch (sample_width) {
  51                 case 16:
  52                         ws = IEC958_AES4_CON_WORDLEN_20_16;
  53                         break;
  54                 case 18:
  55                         ws = IEC958_AES4_CON_WORDLEN_22_18;
  56                         break;
  57                 case 20:
  58                         ws = IEC958_AES4_CON_WORDLEN_20_16 |
  59                              IEC958_AES4_CON_MAX_WORDLEN_24;
  60                         break;
  61                 case 24:
  62                 case 32: /* Assume 24-bit width for 32-bit samples. */
  63                         ws = IEC958_AES4_CON_WORDLEN_24_20 |
  64                              IEC958_AES4_CON_MAX_WORDLEN_24;
  65                         break;
  66
  67                 default:
  68                         return -EINVAL;
  69                 }
  70         }
  71
  72         memset(cs, 0, len);
  73
  74         cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE;
  75         cs[1] = IEC958_AES1_CON_GENERAL;
  76         cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC;
  77         cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | fs;
  78
  79         if (len > 4)
  80                 cs[4] = ws;
  81
  82         return len;
  83 }
  84
  85 /**
  86  * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
  87  * @runtime: pcm runtime structure with ->rate filled in
  88  * @cs: channel status buffer, at least four bytes
  89  * @len: length of channel status buffer
  90  *
  91  * Create the consumer format channel status data in @cs of maximum size
  92  * @len corresponding to the parameters of the PCM runtime @runtime.
  93  *
  94  * Drivers may wish to tweak the contents of the buffer after creation.
  95  *
  96  * Returns: length of buffer, or negative error code if something failed.
  97  */
  98 int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
  99         size_t len)
 100 {
 101         return create_iec958_consumer(runtime->rate,
 102                                       snd_pcm_format_width(runtime->format),
 103                                       cs, len);
 104 }
 105 EXPORT_SYMBOL(snd_pcm_create_iec958_consumer);
 106
 107 /**
 108  * snd_pcm_create_iec958_consumer_hw_params - create IEC958 channel status
 109  * @hw_params: the hw_params instance for extracting rate and sample format
 110  * @cs: channel status buffer, at least four bytes
 111  * @len: length of channel status buffer
 112  *
 113  * Create the consumer format channel status data in @cs of maximum size
 114  * @len corresponding to the parameters of the PCM runtime @runtime.
 115  *
 116  * Drivers may wish to tweak the contents of the buffer after creation.
 117  *
 118  * Returns: length of buffer, or negative error code if something failed.
 119  */
 120 int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params,
 121                                              u8 *cs, size_t len)
 122 {
 123         return create_iec958_consumer(params_rate(params), params_width(params),
 124                                       cs, len);
 125 }
 126 EXPORT_SYMBOL(snd_pcm_create_iec958_consumer_hw_params);