// SPDX-License-Identifier: GPL-2.0-only
|
/*
|
* PCM DRM helpers
|
*/
|
#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);
|
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[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);
|
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[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);
|
