Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
838d1631 RK |
2 | /* |
3 | * PCM DRM helpers | |
838d1631 RK |
4 | */ |
5 | #include <linux/export.h> | |
6 | #include <drm/drm_edid.h> | |
7 | #include <sound/pcm.h> | |
8 | #include <sound/pcm_drm_eld.h> | |
9 | ||
10 | static const unsigned int eld_rates[] = { | |
11 | 32000, | |
12 | 44100, | |
13 | 48000, | |
14 | 88200, | |
15 | 96000, | |
16 | 176400, | |
17 | 192000, | |
18 | }; | |
19 | ||
20 | static unsigned int sad_max_channels(const u8 *sad) | |
21 | { | |
22 | return 1 + (sad[0] & 7); | |
23 | } | |
24 | ||
25 | static int eld_limit_rates(struct snd_pcm_hw_params *params, | |
26 | struct snd_pcm_hw_rule *rule) | |
27 | { | |
28 | struct snd_interval *r = hw_param_interval(params, rule->var); | |
b55f9fdc | 29 | const struct snd_interval *c; |
838d1631 RK |
30 | unsigned int rate_mask = 7, i; |
31 | const u8 *sad, *eld = rule->private; | |
32 | ||
33 | sad = drm_eld_sad(eld); | |
34 | if (sad) { | |
b55f9fdc | 35 | c = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS); |
838d1631 RK |
36 | |
37 | for (i = drm_eld_sad_count(eld); i > 0; i--, sad += 3) { | |
38 | unsigned max_channels = sad_max_channels(sad); | |
39 | ||
40 | /* | |
41 | * Exclude SADs which do not include the | |
42 | * requested number of channels. | |
43 | */ | |
44 | if (c->min <= max_channels) | |
45 | rate_mask |= sad[1]; | |
46 | } | |
47 | } | |
48 | ||
49 | return snd_interval_list(r, ARRAY_SIZE(eld_rates), eld_rates, | |
50 | rate_mask); | |
51 | } | |
52 | ||
53 | static int eld_limit_channels(struct snd_pcm_hw_params *params, | |
54 | struct snd_pcm_hw_rule *rule) | |
55 | { | |
56 | struct snd_interval *c = hw_param_interval(params, rule->var); | |
b55f9fdc | 57 | const struct snd_interval *r; |
838d1631 RK |
58 | struct snd_interval t = { .min = 1, .max = 2, .integer = 1, }; |
59 | unsigned int i; | |
60 | const u8 *sad, *eld = rule->private; | |
61 | ||
62 | sad = drm_eld_sad(eld); | |
63 | if (sad) { | |
64 | unsigned int rate_mask = 0; | |
65 | ||
66 | /* Convert the rate interval to a mask */ | |
b55f9fdc | 67 | r = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE); |
838d1631 RK |
68 | for (i = 0; i < ARRAY_SIZE(eld_rates); i++) |
69 | if (r->min <= eld_rates[i] && r->max >= eld_rates[i]) | |
70 | rate_mask |= BIT(i); | |
71 | ||
72 | for (i = drm_eld_sad_count(eld); i > 0; i--, sad += 3) | |
73 | if (rate_mask & sad[1]) | |
74 | t.max = max(t.max, sad_max_channels(sad)); | |
75 | } | |
76 | ||
77 | return snd_interval_refine(c, &t); | |
78 | } | |
79 | ||
80 | int snd_pcm_hw_constraint_eld(struct snd_pcm_runtime *runtime, void *eld) | |
81 | { | |
82 | int ret; | |
83 | ||
84 | ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE, | |
85 | eld_limit_rates, eld, | |
86 | SNDRV_PCM_HW_PARAM_CHANNELS, -1); | |
87 | if (ret < 0) | |
88 | return ret; | |
89 | ||
90 | ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS, | |
91 | eld_limit_channels, eld, | |
92 | SNDRV_PCM_HW_PARAM_RATE, -1); | |
93 | ||
94 | return ret; | |
95 | } | |
96 | EXPORT_SYMBOL_GPL(snd_pcm_hw_constraint_eld); |