[PATCH v2 3/6] ALSA: hda/tegra: Update scratch reg. communication

[Mohan Kumar <mkumard@nvidia.com>]

Tegra234 chip scratch register communication between audio
and hdmi driver differs slightly in the way it triggers the
interrupt compared to legacy chips. Interrupt is triggered
by writing non-zero values to verb 0xF80 instead of 31st bit
of scratch register.

DP MST support changed the NID to be used for scratch register
read/write from audio function group NID to Converter widget NID.

Signed-off-by: Mohan Kumar <mkumard@nvidia.com>
---
 sound/pci/hda/patch_hdmi.c | 64 ++++++++++++++++++++++++++++----------
 1 file changed, 48 insertions(+), 16 deletions(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 879f886d2406..2eebb302a7bd 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -162,6 +162,8 @@ struct hdmi_spec {
 	bool dyn_pin_out;
 	bool dyn_pcm_assign;
 	bool dyn_pcm_no_legacy;
+	/* hdmi interrupt trigger control flag for Nvidia codec */
+	bool hdmi_intr_trig_ctrl;
 	bool intel_hsw_fixup;	/* apply Intel platform-specific fixups */
 	/*
 	 * Non-generic VIA/NVIDIA specific
@@ -3721,8 +3723,11 @@ static int patch_nvhdmi_legacy(struct hda_codec *codec)
  * +-----------------------------------|
  *
  * Note that for the trigger bit to take effect it needs to change value
- * (i.e. it needs to be toggled).
+ * (i.e. it needs to be toggled). The trigger bit is not applicable from
+ * TEGRA234 chip onwards, as new verb id 0xf80 will be used for interrupt
+ * trigger to hdmi.
  */
+#define NVIDIA_SET_HOST_INTR		0xf80
 #define NVIDIA_GET_SCRATCH0		0xfa6
 #define NVIDIA_SET_SCRATCH0_BYTE0	0xfa7
 #define NVIDIA_SET_SCRATCH0_BYTE1	0xfa8
@@ -3741,25 +3746,38 @@ static int patch_nvhdmi_legacy(struct hda_codec *codec)
  * The format parameter is the HDA audio format (see AC_FMT_*). If set to 0,
  * the format is invalidated so that the HDMI codec can be disabled.
  */
-static void tegra_hdmi_set_format(struct hda_codec *codec, unsigned int format)
+static void tegra_hdmi_set_format(struct hda_codec *codec,
+				  hda_nid_t cvt_nid,
+				  unsigned int format)
 {
 	unsigned int value;
+	unsigned int nid = NVIDIA_AFG_NID;
+	struct hdmi_spec *spec = codec->spec;
+
+	/*
+	 * Tegra HDA codec design from TEGRA234 chip onwards support DP MST.
+	 * This resulted in moving scratch registers from audio function
+	 * group to converter widget context. So CVT NID should be used for
+	 * scratch register read/write for DP MST supported Tegra HDA codec.
+	 */
+	if (codec->dp_mst)
+		nid = cvt_nid;
 
 	/* bits [31:30] contain the trigger and valid bits */
-	value = snd_hda_codec_read(codec, NVIDIA_AFG_NID, 0,
+	value = snd_hda_codec_read(codec, nid, 0,
 				   NVIDIA_GET_SCRATCH0, 0);
 	value = (value >> 24) & 0xff;
 
 	/* bits [15:0] are used to store the HDA format */
-	snd_hda_codec_write(codec, NVIDIA_AFG_NID, 0,
+	snd_hda_codec_write(codec, nid, 0,
 			    NVIDIA_SET_SCRATCH0_BYTE0,
 			    (format >> 0) & 0xff);
-	snd_hda_codec_write(codec, NVIDIA_AFG_NID, 0,
+	snd_hda_codec_write(codec, nid, 0,
 			    NVIDIA_SET_SCRATCH0_BYTE1,
 			    (format >> 8) & 0xff);
 
 	/* bits [16:24] are unused */
-	snd_hda_codec_write(codec, NVIDIA_AFG_NID, 0,
+	snd_hda_codec_write(codec, nid, 0,
 			    NVIDIA_SET_SCRATCH0_BYTE2, 0);
 
 	/*
@@ -3771,15 +3789,28 @@ static void tegra_hdmi_set_format(struct hda_codec *codec, unsigned int format)
 	else
 		value |= NVIDIA_SCRATCH_VALID;
 
-	/*
-	 * Whenever the trigger bit is toggled, an interrupt is raised in the
-	 * HDMI codec. The HDMI driver will use that as trigger to update its
-	 * configuration.
-	 */
-	value ^= NVIDIA_SCRATCH_TRIGGER;
+	if (spec->hdmi_intr_trig_ctrl) {
+		/*
+		 * For Tegra HDA Codec design from TEGRA234 onwards, the
+		 * Interrupt to hdmi driver is triggered by writing
+		 * non-zero values to verb 0xF80 instead of 31st bit of
+		 * scratch register.
+		 */
+		snd_hda_codec_write(codec, nid, 0,
+				NVIDIA_SET_SCRATCH0_BYTE3, value);
+		snd_hda_codec_write(codec, nid, 0,
+				NVIDIA_SET_HOST_INTR, 0x1);
+	} else {
+		/*
+		 * Whenever the 31st trigger bit is toggled, an interrupt is raised
+		 * in the HDMI codec. The HDMI driver will use that as trigger
+		 * to update its configuration.
+		 */
+		value ^= NVIDIA_SCRATCH_TRIGGER;
 
-	snd_hda_codec_write(codec, NVIDIA_AFG_NID, 0,
-			    NVIDIA_SET_SCRATCH0_BYTE3, value);
+		snd_hda_codec_write(codec, nid, 0,
+				NVIDIA_SET_SCRATCH0_BYTE3, value);
+	}
 }
 
 static int tegra_hdmi_pcm_prepare(struct hda_pcm_stream *hinfo,
@@ -3796,7 +3827,7 @@ static int tegra_hdmi_pcm_prepare(struct hda_pcm_stream *hinfo,
 		return err;
 
 	/* notify the HDMI codec of the format change */
-	tegra_hdmi_set_format(codec, format);
+	tegra_hdmi_set_format(codec, hinfo->nid, format);
 
 	return 0;
 }
@@ -3806,7 +3837,7 @@ static int tegra_hdmi_pcm_cleanup(struct hda_pcm_stream *hinfo,
 				  struct snd_pcm_substream *substream)
 {
 	/* invalidate the format in the HDMI codec */
-	tegra_hdmi_set_format(codec, 0);
+	tegra_hdmi_set_format(codec, hinfo->nid, 0);
 
 	return generic_hdmi_playback_pcm_cleanup(hinfo, codec, substream);
 }
@@ -3906,6 +3937,7 @@ static int patch_tegra234_hdmi(struct hda_codec *codec)
 	spec = codec->spec;
 	spec->dyn_pin_out = true;
 	spec->dyn_pcm_assign = true;
+	spec->hdmi_intr_trig_ctrl = true;
 
 	return tegra_hdmi_init(codec);
 }
-- 
2.17.1