ALSA: pcm: add DRM ELD helper (838d1631) · Commits · 戴 / test

include/sound/pcm_drm_eld.h

0 → 100644

+6 −0

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		#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

sound/core/Kconfig

+3 −0

Original line number	Diff line number	Diff line
		@@ -6,6 +6,9 @@ config SND_PCM
		tristate
		select SND_TIMER

		config SND_PCM_ELD
		bool

		config SND_DMAENGINE_PCM
		tristate

sound/core/Makefile

+1 −0

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		@@ -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)

sound/core/pcm_drm_eld.c

0 → 100644

+99 −0

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		/*
		* 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);

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