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
25 static const unsigned int eld_rates[] = {
26 32000,
27 44100,
28 48000,
29 88200,
30 96000,
31 176400,
32 192000,
33 };
34
map_rate_families(const u8 * sad,unsigned int mask_32000,unsigned int mask_44100,unsigned int mask_48000)35 static 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
sad_rate_mask(const u8 * sad)51 static 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
sad_max_channels(const u8 * sad)75 static 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
eld_limit_rates(struct snd_pcm_hw_params * params,struct snd_pcm_hw_rule * rule)93 static 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
eld_limit_channels(struct snd_pcm_hw_params * params,struct snd_pcm_hw_rule * rule)121 static 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
snd_pcm_hw_constraint_eld(struct snd_pcm_runtime * runtime,void * eld)148 int 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 }
164 EXPORT_SYMBOL_GPL(snd_pcm_hw_constraint_eld);
165