drm: bridge/dw_hdmi-ahb-audio: basic support for multi-channel PCM audio

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.

Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c b/drivers/gpu/drm/bridge/dw_hdmi-ahb-audio.c
index fbcef2695c93e004594a543c24b3527913b1ef62..e779c16f1e67d6da132fa2060941c523fb8d59bc 100644 (file)
--- 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;
@@ -354,7 +397,7 @@ 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) {
@@ -382,11 +425,23 @@ 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: