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