diff options
Diffstat (limited to 'sound/core/pcm_iec958.c')
| -rw-r--r-- | sound/core/pcm_iec958.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/sound/core/pcm_iec958.c b/sound/core/pcm_iec958.c new file mode 100644 index 000000000..5e6aed64f --- /dev/null +++ b/sound/core/pcm_iec958.c @@ -0,0 +1,126 @@ +/* + * 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); |