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 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 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 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 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 } 120 121 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 } 147 148 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