| Russell King | 9203dd0 | 2015-05-09 11:26:47 +0100 | [diff] [blame^] | 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_iec958.h> |
| 13 | |
| 14 | /** |
| 15 | * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status |
| 16 | * @runtime: pcm runtime structure with ->rate filled in |
| 17 | * @cs: channel status buffer, at least four bytes |
| 18 | * @len: length of channel status buffer |
| 19 | * |
| 20 | * Create the consumer format channel status data in @cs of maximum size |
| 21 | * @len corresponding to the parameters of the PCM runtime @runtime. |
| 22 | * |
| 23 | * Drivers may wish to tweak the contents of the buffer after creation. |
| 24 | * |
| 25 | * Returns: length of buffer, or negative error code if something failed. |
| 26 | */ |
| 27 | int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs, |
| 28 | size_t len) |
| 29 | { |
| 30 | unsigned int fs, ws; |
| 31 | |
| 32 | if (len < 4) |
| 33 | return -EINVAL; |
| 34 | |
| 35 | switch (runtime->rate) { |
| 36 | case 32000: |
| 37 | fs = IEC958_AES3_CON_FS_32000; |
| 38 | break; |
| 39 | case 44100: |
| 40 | fs = IEC958_AES3_CON_FS_44100; |
| 41 | break; |
| 42 | case 48000: |
| 43 | fs = IEC958_AES3_CON_FS_48000; |
| 44 | break; |
| 45 | case 88200: |
| 46 | fs = IEC958_AES3_CON_FS_88200; |
| 47 | break; |
| 48 | case 96000: |
| 49 | fs = IEC958_AES3_CON_FS_96000; |
| 50 | break; |
| 51 | case 176400: |
| 52 | fs = IEC958_AES3_CON_FS_176400; |
| 53 | break; |
| 54 | case 192000: |
| 55 | fs = IEC958_AES3_CON_FS_192000; |
| 56 | break; |
| 57 | default: |
| 58 | return -EINVAL; |
| 59 | } |
| 60 | |
| 61 | if (len > 4) { |
| 62 | switch (snd_pcm_format_width(runtime->format)) { |
| 63 | case 16: |
| 64 | ws = IEC958_AES4_CON_WORDLEN_20_16; |
| 65 | break; |
| 66 | case 18: |
| 67 | ws = IEC958_AES4_CON_WORDLEN_22_18; |
| 68 | break; |
| 69 | case 20: |
| 70 | ws = IEC958_AES4_CON_WORDLEN_20_16 | |
| 71 | IEC958_AES4_CON_MAX_WORDLEN_24; |
| 72 | break; |
| 73 | case 24: |
| 74 | ws = IEC958_AES4_CON_WORDLEN_24_20 | |
| 75 | IEC958_AES4_CON_MAX_WORDLEN_24; |
| 76 | break; |
| 77 | |
| 78 | default: |
| 79 | return -EINVAL; |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | memset(cs, 0, len); |
| 84 | |
| 85 | cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE; |
| 86 | cs[1] = IEC958_AES1_CON_GENERAL; |
| 87 | cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC; |
| 88 | cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | fs; |
| 89 | |
| 90 | if (len > 4) |
| 91 | cs[4] = ws; |
| 92 | |
| 93 | return len; |
| 94 | } |
| 95 | EXPORT_SYMBOL(snd_pcm_create_iec958_consumer); |