1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  PCM DRM helpers
4 */
5#include <linux/bitfield.h>
6#include <linux/export.h>
7#include <linux/hdmi.h>
8#include <drm/drm_edid.h>
9#include <drm/drm_eld.h>
10#include <sound/pcm.h>
11#include <sound/pcm_drm_eld.h>
12
13#define SAD0_CHANNELS_MASK	GENMASK(2, 0) /* max number of channels - 1 */
14#define SAD0_FORMAT_MASK	GENMASK(6, 3) /* audio format */
15
16#define SAD1_RATE_MASK		GENMASK(6, 0) /* bitfield of supported rates */
17#define SAD1_RATE_32000_MASK	BIT(0)
18#define SAD1_RATE_44100_MASK	BIT(1)
19#define SAD1_RATE_48000_MASK	BIT(2)
20#define SAD1_RATE_88200_MASK	BIT(3)
21#define SAD1_RATE_96000_MASK	BIT(4)
22#define SAD1_RATE_176400_MASK	BIT(5)
23#define SAD1_RATE_192000_MASK	BIT(6)
24
25static const unsigned int eld_rates[] = {
26	32000,
27	44100,
28	48000,
29	88200,
30	96000,
31	176400,
32	192000,
33};
34
35static unsigned int map_rate_families(const u8 *sad,
36				      unsigned int mask_32000,
37				      unsigned int mask_44100,
38				      unsigned int mask_48000)
39{
40	unsigned int rate_mask = 0;
41
42	if (sad[1] & SAD1_RATE_32000_MASK)
43		rate_mask |= mask_32000;
44	if (sad[1] & (SAD1_RATE_44100_MASK | SAD1_RATE_88200_MASK | SAD1_RATE_176400_MASK))
45		rate_mask |= mask_44100;
46	if (sad[1] & (SAD1_RATE_48000_MASK | SAD1_RATE_96000_MASK | SAD1_RATE_192000_MASK))
47		rate_mask |= mask_48000;
48	return rate_mask;
49}
50
51static unsigned int sad_rate_mask(const u8 *sad)
52{
53	switch (FIELD_GET(SAD0_FORMAT_MASK, sad[0])) {
54	case HDMI_AUDIO_CODING_TYPE_PCM:
55		return sad[1] & SAD1_RATE_MASK;
56	case HDMI_AUDIO_CODING_TYPE_AC3:
57	case HDMI_AUDIO_CODING_TYPE_DTS:
58		return map_rate_families(sad,
59					 SAD1_RATE_32000_MASK,
60					 SAD1_RATE_44100_MASK,
61					 SAD1_RATE_48000_MASK);
62	case HDMI_AUDIO_CODING_TYPE_EAC3:
63	case HDMI_AUDIO_CODING_TYPE_DTS_HD:
64	case HDMI_AUDIO_CODING_TYPE_MLP:
65		return map_rate_families(sad,
66					 0,
67					 SAD1_RATE_176400_MASK,
68					 SAD1_RATE_192000_MASK);
69	default:
70		/* TODO adjust for other compressed formats as well */
71		return sad[1] & SAD1_RATE_MASK;
72	}
73}
74
75static unsigned int sad_max_channels(const u8 *sad)
76{
77	switch (FIELD_GET(SAD0_FORMAT_MASK, sad[0])) {
78	case HDMI_AUDIO_CODING_TYPE_PCM:
79		return 1 + FIELD_GET(SAD0_CHANNELS_MASK, sad[0]);
80	case HDMI_AUDIO_CODING_TYPE_AC3:
81	case HDMI_AUDIO_CODING_TYPE_DTS:
82	case HDMI_AUDIO_CODING_TYPE_EAC3:
83		return 2;
84	case HDMI_AUDIO_CODING_TYPE_DTS_HD:
85	case HDMI_AUDIO_CODING_TYPE_MLP:
86		return 8;
87	default:
88		/* TODO adjust for other compressed formats as well */
89		return 1 + FIELD_GET(SAD0_CHANNELS_MASK, sad[0]);
90	}
91}
92
93static int eld_limit_rates(struct snd_pcm_hw_params *params,
94			   struct snd_pcm_hw_rule *rule)
95{
96	struct snd_interval *r = hw_param_interval(params, rule->var);
97	const struct snd_interval *c;
98	unsigned int rate_mask = 7, i;
99	const u8 *sad, *eld = rule->private;
100
101	sad = drm_eld_sad(eld);
102	if (sad) {
103		c = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
104
105		for (i = drm_eld_sad_count(eld); i > 0; i--, sad += 3) {
106			unsigned max_channels = sad_max_channels(sad);
107
108			/*
109			 * Exclude SADs which do not include the
110			 * requested number of channels.
111			 */
112			if (c->min <= max_channels)
113				rate_mask |= sad_rate_mask(sad);
114		}
115	}
116
117	return snd_interval_list(r, ARRAY_SIZE(eld_rates), eld_rates,
118				 rate_mask);
119}
120
121static int eld_limit_channels(struct snd_pcm_hw_params *params,
122			      struct snd_pcm_hw_rule *rule)
123{
124	struct snd_interval *c = hw_param_interval(params, rule->var);
125	const struct snd_interval *r;
126	struct snd_interval t = { .min = 1, .max = 2, .integer = 1, };
127	unsigned int i;
128	const u8 *sad, *eld = rule->private;
129
130	sad = drm_eld_sad(eld);
131	if (sad) {
132		unsigned int rate_mask = 0;
133
134		/* Convert the rate interval to a mask */
135		r = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
136		for (i = 0; i < ARRAY_SIZE(eld_rates); i++)
137			if (r->min <= eld_rates[i] && r->max >= eld_rates[i])
138				rate_mask |= BIT(i);
139
140		for (i = drm_eld_sad_count(eld); i > 0; i--, sad += 3)
141			if (rate_mask & sad_rate_mask(sad))
142				t.max = max(t.max, sad_max_channels(sad));
143	}
144
145	return snd_interval_refine(c, &t);
146}
147
148int snd_pcm_hw_constraint_eld(struct snd_pcm_runtime *runtime, void *eld)
149{
150	int ret;
151
152	ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
153				  eld_limit_rates, eld,
154				  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
155	if (ret < 0)
156		return ret;
157
158	ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
159				  eld_limit_channels, eld,
160				  SNDRV_PCM_HW_PARAM_RATE, -1);
161
162	return ret;
163}
164EXPORT_SYMBOL_GPL(snd_pcm_hw_constraint_eld);
165