Add basic support for multi-channel PCM audio, with fixed speaker
mappings. This has been tested with an AV receiver, and appears to
work for low sample rates up to 8 channels.
It should be noted that multi-channel mode using the IEC958 alsa-lib
conversion plugin requires correct AES channel status for the AV
receiver to recognise the stream, especially the sample rate bits.
"Not identified" does not work there.
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c | 59 +++++++++++++++++++++++++++++-
1 file changed, 57 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c b/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
index 125b81306254..3a8f32e04b63 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
@@ -62,9 +62,14 @@ enum {
HDMI_AHB_DMA_CONF0_INCR4 = 0,
HDMI_AHB_DMA_CONF0_BURST_MODE = BIT(0),
HDMI_AHB_DMA_MASK_DONE = BIT(7),
+
HDMI_REVISION_ID = 0x0001,
HDMI_IH_AHBDMAAUD_STAT0 = 0x0109,
HDMI_IH_MUTE_AHBDMAAUD_STAT0 = 0x0189,
+ HDMI_FC_AUDICONF2 = 0x1027,
+ HDMI_FC_AUDSCONF = 0x1063,
+ HDMI_FC_AUDSCONF_LAYOUT1 = 1 << 0,
+ HDMI_FC_AUDSCONF_LAYOUT0 = 0 << 0,
HDMI_AHB_DMA_CONF0 = 0x3600,
HDMI_AHB_DMA_START = 0x3601,
HDMI_AHB_DMA_STOP = 0x3602,
@@ -77,6 +82,44 @@ enum {
HDMI_AHB_DMA_BUFFPOL = 0x361a,
};
+struct dw_hdmi_channel_conf {
+ u8 conf1;
+ u8 ca;
+};
+
+/*
+ * The default mapping of ALSA channels to HDMI channels and speaker
+ * allocation bits. Note that we can't do channel remapping here -
+ * channels must be in the same order.
+ *
+ * Mappings for alsa-lib pcm/surround*.conf files:
+ *
+ * Front Sur4.0 Sur4.1 Sur5.0 Sur5.1 Sur7.1
+ * Channels 2 4 6 6 6 8
+ *
+ * Our mapping from ALSA channel to CEA686D speaker name and HDMI channel:
+ *
+ * Number of ALSA channels
+ * ALSA Channel 2 3 4 5 6 7 8
+ * 0 FL:0 = = = = = =
+ * 1 FR:1 = = = = = =
+ * 2 FC:3 RL:4 LFE:2 = = =
+ * 3 RR:5 RL:4 FC:3 = =
+ * 4 RR:5 RL:4 = =
+ * 5 RR:5 = =
+ * 6 RC:6 =
+ * 7 RLC/FRC RLC/FRC
+ */
+static struct dw_hdmi_channel_conf default_hdmi_channel_config[7] = {
+ { 0x03, 0x00 }, /* FL,FR */
+ { 0x0b, 0x02 }, /* FL,FR,FC */
+ { 0x33, 0x08 }, /* FL,FR,RL,RR */
+ { 0x37, 0x09 }, /* FL,FR,LFE,RL,RR */
+ { 0x3f, 0x0b }, /* FL,FR,LFE,FC,RL,RR */
+ { 0x7f, 0x0f }, /* FL,FR,LFE,FC,RL,RR,RC */
+ { 0xff, 0x13 }, /* FL,FR,LFE,FC,RL,RR,[FR]RC,[FR]LC */
+};
+
struct snd_dw_hdmi {
struct snd_card *card;
struct snd_pcm *pcm;
@@ -352,7 +395,7 @@ static int dw_hdmi_prepare(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct snd_dw_hdmi *dw = substream->private_data;
- u8 threshold, conf0, conf1;
+ u8 threshold, conf0, conf1, layout, ca;
/* Setup as per 3.0.5 FSL 4.1.0 BSP */
switch (dw->revision) {
@@ -380,11 +423,23 @@ static int dw_hdmi_prepare(struct snd_pcm_substream *substream)
runtime->hw.fifo_size = threshold * 32;
conf0 |= HDMI_AHB_DMA_CONF0_EN_HLOCK;
- conf1 = (1 << runtime->channels) - 1;
+ conf1 = default_hdmi_channel_config[runtime->channels - 2].conf1;
+ ca = default_hdmi_channel_config[runtime->channels - 2].ca;
+
+ /*
+ * For >2 channel PCM audio, we need to select layout 1
+ * and set an appropriate channel map.
+ */
+ if (runtime->channels > 2)
+ layout = HDMI_FC_AUDSCONF_LAYOUT1;
+ else
+ layout = HDMI_FC_AUDSCONF_LAYOUT0;
writeb_relaxed(threshold, dw->data.base + HDMI_AHB_DMA_THRSLD);
writeb_relaxed(conf0, dw->data.base + HDMI_AHB_DMA_CONF0);
writeb_relaxed(conf1, dw->data.base + HDMI_AHB_DMA_CONF1);
+ writeb_relaxed(layout, dw->data.base + HDMI_FC_AUDSCONF);
+ writeb_relaxed(ca, dw->data.base + HDMI_FC_AUDICONF2);
switch (runtime->format) {
case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE:
--
2.1.0
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