Commit 2112aa03 authored by Jaroslav Kysela's avatar Jaroslav Kysela Committed by Takashi Iwai
Browse files

ALSA: pcm: Introduce MSBITS subformat interface 



Improve granularity of format selection for S32/U32 formats by adding
constants representing 20, 24 and MAX most significant bits.

The MAX means the maximum number of significant bits which can
the physical format hold. For 32-bit formats, MAX is related
to 32 bits. For 8-bit formats, MAX is related to 8 bits etc.

As there is only one user currently (format S32_LE), subformat is
represented by a simple u32 and stores flags only for that one user
alone. The approach of subformat being part of struct snd_pcm_hardware
is a compromise between ALSA and ASoC allowing for
hw_params-intersection code to be alloc/free-less while not adding any
new responsibilities to ASoC runtime structures.

Acked-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarJaroslav Kysela <perex@perex.cz>
Co-developed-by: default avatarCezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: default avatarCezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20231117120610.1755254-2-cezary.rojewski@intel.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 26257869

include/sound/pcm.h

+7 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
struct snd_pcm_hardware {

	unsigned int info;		/* SNDRV_PCM_INFO_* */

	u64 formats;			/* SNDRV_PCM_FMTBIT_* */

	u32 subformats;			/* for S32_LE, SNDRV_PCM_SUBFMTBIT_* */

	unsigned int rates;		/* SNDRV_PCM_RATE_* */

	unsigned int rate_min;		/* min rate */

	unsigned int rate_max;		/* max rate */
@@ -217,6 +218,12 @@ struct snd_pcm_ops { 
#define SNDRV_PCM_FMTBIT_U20		SNDRV_PCM_FMTBIT_U20_BE

#endif



#define _SNDRV_PCM_SUBFMTBIT(fmt)	BIT((__force int)SNDRV_PCM_SUBFORMAT_##fmt)

#define SNDRV_PCM_SUBFMTBIT_STD		_SNDRV_PCM_SUBFMTBIT(STD)

#define SNDRV_PCM_SUBFMTBIT_MSBITS_MAX	_SNDRV_PCM_SUBFMTBIT(MSBITS_MAX)

#define SNDRV_PCM_SUBFMTBIT_MSBITS_20	_SNDRV_PCM_SUBFMTBIT(MSBITS_20)

#define SNDRV_PCM_SUBFMTBIT_MSBITS_24	_SNDRV_PCM_SUBFMTBIT(MSBITS_24)



struct snd_pcm_file {

	struct snd_pcm_substream *substream;

	int no_compat_mmap;

include/uapi/sound/asound.h

+5 −2
Original line number Diff line number Diff line
@@ -142,7 +142,7 @@ struct snd_hwdep_dsp_image { 
 *                                                                           *

 *****************************************************************************/



#define SNDRV_PCM_VERSION		SNDRV_PROTOCOL_VERSION(2, 0, 15)

#define SNDRV_PCM_VERSION		SNDRV_PROTOCOL_VERSION(2, 0, 16)



typedef unsigned long snd_pcm_uframes_t;

typedef signed long snd_pcm_sframes_t;
@@ -267,7 +267,10 @@ typedef int __bitwise snd_pcm_format_t; 


typedef int __bitwise snd_pcm_subformat_t;

#define	SNDRV_PCM_SUBFORMAT_STD		((__force snd_pcm_subformat_t) 0)

#define	SNDRV_PCM_SUBFORMAT_LAST	SNDRV_PCM_SUBFORMAT_STD

#define	SNDRV_PCM_SUBFORMAT_MSBITS_MAX	((__force snd_pcm_subformat_t) 1)

#define	SNDRV_PCM_SUBFORMAT_MSBITS_20	((__force snd_pcm_subformat_t) 2)

#define	SNDRV_PCM_SUBFORMAT_MSBITS_24	((__force snd_pcm_subformat_t) 3)

#define	SNDRV_PCM_SUBFORMAT_LAST	SNDRV_PCM_SUBFORMAT_MSBITS_24



#define SNDRV_PCM_INFO_MMAP		0x00000001	/* hardware supports mmap */

#define SNDRV_PCM_INFO_MMAP_VALID	0x00000002	/* period data are valid during transfer */

sound/core/pcm.c

+3 −0
Original line number Diff line number Diff line
@@ -265,6 +265,9 @@ static const char * const snd_pcm_access_names[] = { 


static const char * const snd_pcm_subformat_names[] = {

	SUBFORMAT(STD), 

	SUBFORMAT(MSBITS_MAX),

	SUBFORMAT(MSBITS_20),

	SUBFORMAT(MSBITS_24),

};



static const char * const snd_pcm_tstamp_mode_names[] = {

sound/core/pcm_native.c

+53 −2
Original line number Diff line number Diff line
@@ -479,6 +479,7 @@ static int fixup_unreferenced_params(struct snd_pcm_substream *substream, 
{

	const struct snd_interval *i;

	const struct snd_mask *m;

	struct snd_mask *m_rw;

	int err;



	if (!params->msbits) {
@@ -487,6 +488,22 @@ static int fixup_unreferenced_params(struct snd_pcm_substream *substream, 
			params->msbits = snd_interval_value(i);

	}



	if (params->msbits) {

		m = hw_param_mask_c(params, SNDRV_PCM_HW_PARAM_FORMAT);

		if (snd_mask_single(m)) {

			snd_pcm_format_t format = (__force snd_pcm_format_t)snd_mask_min(m);



			if (snd_pcm_format_linear(format) &&

			    snd_pcm_format_width(format) != params->msbits) {

				m_rw = hw_param_mask(params, SNDRV_PCM_HW_PARAM_SUBFORMAT);

				snd_mask_reset(m_rw,

					       (__force unsigned)SNDRV_PCM_SUBFORMAT_MSBITS_MAX);

				if (snd_mask_empty(m_rw))

					return -EINVAL;

			}

		}

	}



	if (!params->rate_den) {

		i = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);

		if (snd_interval_single(i)) {
@@ -2483,6 +2500,41 @@ static int snd_pcm_hw_rule_buffer_bytes_max(struct snd_pcm_hw_params *params, 
	return snd_interval_refine(hw_param_interval(params, rule->var), &t);

}		



static int snd_pcm_hw_rule_subformats(struct snd_pcm_hw_params *params,

				      struct snd_pcm_hw_rule *rule)

{

	struct snd_mask *sfmask = hw_param_mask(params, SNDRV_PCM_HW_PARAM_SUBFORMAT);

	struct snd_mask *fmask = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);

	u32 *subformats = rule->private;

	snd_pcm_format_t f;

	struct snd_mask m;



	snd_mask_none(&m);

	/* All PCMs support at least the default STD subformat. */

	snd_mask_set(&m, (__force unsigned)SNDRV_PCM_SUBFORMAT_STD);



	pcm_for_each_format(f) {

		if (!snd_mask_test(fmask, (__force unsigned)f))

			continue;



		if (f == SNDRV_PCM_FORMAT_S32_LE && *subformats)

			m.bits[0] |= *subformats;

		else if (snd_pcm_format_linear(f))

			snd_mask_set(&m, (__force unsigned)SNDRV_PCM_SUBFORMAT_MSBITS_MAX);

	}



	return snd_mask_refine(sfmask, &m);

}



static int snd_pcm_hw_constraint_subformats(struct snd_pcm_runtime *runtime,

					   unsigned int cond, u32 *subformats)

{

	return snd_pcm_hw_rule_add(runtime, cond, -1,

				   snd_pcm_hw_rule_subformats, (void *)subformats,

				   SNDRV_PCM_HW_PARAM_SUBFORMAT,

				   SNDRV_PCM_HW_PARAM_FORMAT, -1);

}



static int snd_pcm_hw_constraints_init(struct snd_pcm_substream *substream)

{

	struct snd_pcm_runtime *runtime = substream->runtime;
@@ -2634,8 +2686,7 @@ static int snd_pcm_hw_constraints_complete(struct snd_pcm_substream *substream) 
	if (err < 0)

		return err;



	err = snd_pcm_hw_constraint_mask(runtime, SNDRV_PCM_HW_PARAM_SUBFORMAT,

					 PARAM_MASK_BIT(SNDRV_PCM_SUBFORMAT_STD));

	err = snd_pcm_hw_constraint_subformats(runtime, 0, &hw->subformats);

	if (err < 0)

		return err;

tools/include/uapi/sound/asound.h

+5 −2
Original line number Diff line number Diff line
@@ -142,7 +142,7 @@ struct snd_hwdep_dsp_image { 
 *                                                                           *

 *****************************************************************************/



#define SNDRV_PCM_VERSION		SNDRV_PROTOCOL_VERSION(2, 0, 15)

#define SNDRV_PCM_VERSION		SNDRV_PROTOCOL_VERSION(2, 0, 16)



typedef unsigned long snd_pcm_uframes_t;

typedef signed long snd_pcm_sframes_t;
@@ -267,7 +267,10 @@ typedef int __bitwise snd_pcm_format_t; 


typedef int __bitwise snd_pcm_subformat_t;

#define	SNDRV_PCM_SUBFORMAT_STD		((__force snd_pcm_subformat_t) 0)

#define	SNDRV_PCM_SUBFORMAT_LAST	SNDRV_PCM_SUBFORMAT_STD

#define	SNDRV_PCM_SUBFORMAT_MSBITS_MAX	((__force snd_pcm_subformat_t) 1)

#define	SNDRV_PCM_SUBFORMAT_MSBITS_20	((__force snd_pcm_subformat_t) 2)

#define	SNDRV_PCM_SUBFORMAT_MSBITS_24	((__force snd_pcm_subformat_t) 3)

#define	SNDRV_PCM_SUBFORMAT_LAST	SNDRV_PCM_SUBFORMAT_MSBITS_24



#define SNDRV_PCM_INFO_MMAP		0x00000001	/* hardware supports mmap */

#define SNDRV_PCM_INFO_MMAP_VALID	0x00000002	/* period data are valid during transfer */