diff options
Diffstat (limited to 'sound/core/pcm_drm_eld.c')
-rw-r--r-- | sound/core/pcm_drm_eld.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/sound/core/pcm_drm_eld.c b/sound/core/pcm_drm_eld.c new file mode 100644 index 0000000000..0707507197 --- /dev/null +++ b/sound/core/pcm_drm_eld.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PCM DRM helpers + */ +#include <linux/bitfield.h> +#include <linux/export.h> +#include <linux/hdmi.h> +#include <drm/drm_edid.h> +#include <sound/pcm.h> +#include <sound/pcm_drm_eld.h> + +#define SAD0_CHANNELS_MASK GENMASK(2, 0) /* max number of channels - 1 */ +#define SAD0_FORMAT_MASK GENMASK(6, 3) /* audio format */ + +#define SAD1_RATE_MASK GENMASK(6, 0) /* bitfield of supported rates */ +#define SAD1_RATE_32000_MASK BIT(0) +#define SAD1_RATE_44100_MASK BIT(1) +#define SAD1_RATE_48000_MASK BIT(2) +#define SAD1_RATE_88200_MASK BIT(3) +#define SAD1_RATE_96000_MASK BIT(4) +#define SAD1_RATE_176400_MASK BIT(5) +#define SAD1_RATE_192000_MASK BIT(6) + +static const unsigned int eld_rates[] = { + 32000, + 44100, + 48000, + 88200, + 96000, + 176400, + 192000, +}; + +static unsigned int map_rate_families(const u8 *sad, + unsigned int mask_32000, + unsigned int mask_44100, + unsigned int mask_48000) +{ + unsigned int rate_mask = 0; + + if (sad[1] & SAD1_RATE_32000_MASK) + rate_mask |= mask_32000; + if (sad[1] & (SAD1_RATE_44100_MASK | SAD1_RATE_88200_MASK | SAD1_RATE_176400_MASK)) + rate_mask |= mask_44100; + if (sad[1] & (SAD1_RATE_48000_MASK | SAD1_RATE_96000_MASK | SAD1_RATE_192000_MASK)) + rate_mask |= mask_48000; + return rate_mask; +} + +static unsigned int sad_rate_mask(const u8 *sad) +{ + switch (FIELD_GET(SAD0_FORMAT_MASK, sad[0])) { + case HDMI_AUDIO_CODING_TYPE_PCM: + return sad[1] & SAD1_RATE_MASK; + case HDMI_AUDIO_CODING_TYPE_AC3: + case HDMI_AUDIO_CODING_TYPE_DTS: + return map_rate_families(sad, + SAD1_RATE_32000_MASK, + SAD1_RATE_44100_MASK, + SAD1_RATE_48000_MASK); + case HDMI_AUDIO_CODING_TYPE_EAC3: + case HDMI_AUDIO_CODING_TYPE_DTS_HD: + case HDMI_AUDIO_CODING_TYPE_MLP: + return map_rate_families(sad, + 0, + SAD1_RATE_176400_MASK, + SAD1_RATE_192000_MASK); + default: + /* TODO adjust for other compressed formats as well */ + return sad[1] & SAD1_RATE_MASK; + } +} + +static unsigned int sad_max_channels(const u8 *sad) +{ + switch (FIELD_GET(SAD0_FORMAT_MASK, sad[0])) { + case HDMI_AUDIO_CODING_TYPE_PCM: + return 1 + FIELD_GET(SAD0_CHANNELS_MASK, sad[0]); + case HDMI_AUDIO_CODING_TYPE_AC3: + case HDMI_AUDIO_CODING_TYPE_DTS: + case HDMI_AUDIO_CODING_TYPE_EAC3: + return 2; + case HDMI_AUDIO_CODING_TYPE_DTS_HD: + case HDMI_AUDIO_CODING_TYPE_MLP: + return 8; + default: + /* TODO adjust for other compressed formats as well */ + return 1 + FIELD_GET(SAD0_CHANNELS_MASK, sad[0]); + } +} + +static int eld_limit_rates(struct snd_pcm_hw_params *params, + struct snd_pcm_hw_rule *rule) +{ + struct snd_interval *r = hw_param_interval(params, rule->var); + const struct snd_interval *c; + unsigned int rate_mask = 7, i; + const u8 *sad, *eld = rule->private; + + sad = drm_eld_sad(eld); + if (sad) { + c = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS); + + for (i = drm_eld_sad_count(eld); i > 0; i--, sad += 3) { + unsigned max_channels = sad_max_channels(sad); + + /* + * Exclude SADs which do not include the + * requested number of channels. + */ + if (c->min <= max_channels) + rate_mask |= sad_rate_mask(sad); + } + } + + return snd_interval_list(r, ARRAY_SIZE(eld_rates), eld_rates, + rate_mask); +} + +static int eld_limit_channels(struct snd_pcm_hw_params *params, + struct snd_pcm_hw_rule *rule) +{ + struct snd_interval *c = hw_param_interval(params, rule->var); + const struct snd_interval *r; + struct snd_interval t = { .min = 1, .max = 2, .integer = 1, }; + unsigned int i; + const u8 *sad, *eld = rule->private; + + sad = drm_eld_sad(eld); + if (sad) { + unsigned int rate_mask = 0; + + /* Convert the rate interval to a mask */ + r = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE); + for (i = 0; i < ARRAY_SIZE(eld_rates); i++) + if (r->min <= eld_rates[i] && r->max >= eld_rates[i]) + rate_mask |= BIT(i); + + for (i = drm_eld_sad_count(eld); i > 0; i--, sad += 3) + if (rate_mask & sad_rate_mask(sad)) + t.max = max(t.max, sad_max_channels(sad)); + } + + return snd_interval_refine(c, &t); +} + +int snd_pcm_hw_constraint_eld(struct snd_pcm_runtime *runtime, void *eld) +{ + int ret; + + ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE, + eld_limit_rates, eld, + SNDRV_PCM_HW_PARAM_CHANNELS, -1); + if (ret < 0) + return ret; + + ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS, + eld_limit_channels, eld, + SNDRV_PCM_HW_PARAM_RATE, -1); + + return ret; +} +EXPORT_SYMBOL_GPL(snd_pcm_hw_constraint_eld); |