Add a helper for the EDID like data structure, which is typically passed from a HDMI adapter to its associated audio driver. This informs the audio driver of the capabilities of the attached HDMI sink.
Signed-off-by: Russell King rmk+kernel@arm.linux.org.uk --- include/sound/pcm_drm_eld.h | 6 +++ sound/core/Kconfig | 3 ++ sound/core/Makefile | 1 + sound/core/pcm_drm_eld.c | 99 +++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 109 insertions(+) create mode 100644 include/sound/pcm_drm_eld.h create mode 100644 sound/core/pcm_drm_eld.c
diff --git a/include/sound/pcm_drm_eld.h b/include/sound/pcm_drm_eld.h new file mode 100644 index 000000000000..93357b25d2e2 --- /dev/null +++ b/include/sound/pcm_drm_eld.h @@ -0,0 +1,6 @@ +#ifndef __SOUND_PCM_DRM_ELD_H +#define __SOUND_PCM_DRM_ELD_H + +int snd_pcm_hw_constraint_eld(struct snd_pcm_runtime *runtime, void *eld); + +#endif diff --git a/sound/core/Kconfig b/sound/core/Kconfig index 313f22e9d929..b534c8a6046b 100644 --- a/sound/core/Kconfig +++ b/sound/core/Kconfig @@ -6,6 +6,9 @@ config SND_PCM tristate select SND_TIMER
+config SND_PCM_ELD + bool + config SND_DMAENGINE_PCM tristate
diff --git a/sound/core/Makefile b/sound/core/Makefile index 4daf2f58261c..591b49157b4d 100644 --- a/sound/core/Makefile +++ b/sound/core/Makefile @@ -13,6 +13,7 @@ snd-$(CONFIG_SND_JACK) += jack.o snd-pcm-y := pcm.o pcm_native.o pcm_lib.o pcm_timer.o pcm_misc.o \ pcm_memory.o memalloc.o snd-pcm-$(CONFIG_SND_DMA_SGBUF) += sgbuf.o +snd-pcm-$(CONFIG_SND_PCM_ELD) += pcm_drm_eld.o
# for trace-points CFLAGS_pcm_lib.o := -I$(src) diff --git a/sound/core/pcm_drm_eld.c b/sound/core/pcm_drm_eld.c new file mode 100644 index 000000000000..e70379fb63d0 --- /dev/null +++ b/sound/core/pcm_drm_eld.c @@ -0,0 +1,99 @@ +/* + * 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 <drm/drm_edid.h> +#include <sound/pcm.h> +#include <sound/pcm_drm_eld.h> + +static const unsigned int eld_rates[] = { + 32000, + 44100, + 48000, + 88200, + 96000, + 176400, + 192000, +}; + +static unsigned int sad_max_channels(const u8 *sad) +{ + return 1 + (sad[0] & 7); +} + +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); + 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(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[1]; + } + } + + 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); + 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(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[1]) + 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);