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 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, 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(r, ARRAY_SIZE(eld_rates), eld_rates, 117 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, 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(c, &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, 0, SNDRV_PCM_HW_PARAM_RATE, 152 eld_limit_rates, eld, 153 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 154 if (ret < 0) 155 return ret; 156 157 ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS, 158 eld_limit_channels, eld, 159 SNDRV_PCM_HW_PARAM_RATE, -1); 160 161 return ret; 162 } 163 EXPORT_SYMBOL_GPL(snd_pcm_hw_constraint_eld); 164