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From:   Vijendar Mukunda <Vijendar.Mukunda@amd.com>
CC:     <Alexander.Deucher@amd.com>,
        Ravulapati Vishnu vardhan rao 
        <Vishnuvardhanrao.Ravulapati@amd.com>,
        Vijendar Mukunda <Vijendar.Mukunda@amd.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Maruthi Bayyavarapu <maruthi.bayyavarapu@amd.com>,
        YueHaibing <yuehaibing@huawei.com>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
        "moderated list:SOUND - SOC LAYER / DYNAMIC AUDIO POWER MANAGEM..." 
        <alsa-devel@alsa-project.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: [PATCH] ASoC: amd: Reporting accurate hw_ptr for acp3x dma
Date:   Fri, 10 May 2019 07:11:07 +0530
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From: Ravulapati Vishnu vardhan rao <Vishnuvardhanrao.Ravulapati@amd.com>

acp3x dma pointer callback has issues in reporting hw_ptr.
Modified logic to use linear position registers to
retrieve accurate hw_ptr.

Signed-off-by: Ravulapati Vishnu vardhan rao <Vishnuvardhanrao.Ravulapati@amd.com>
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
---
 sound/soc/amd/raven/acp3x-pcm-dma.c | 43 ++++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 12 deletions(-)

diff --git a/sound/soc/amd/raven/acp3x-pcm-dma.c b/sound/soc/amd/raven/acp3x-pcm-dma.c
index 9775bda..a4ade6b 100644
--- a/sound/soc/amd/raven/acp3x-pcm-dma.c
+++ b/sound/soc/amd/raven/acp3x-pcm-dma.c
@@ -32,6 +32,7 @@ struct i2s_stream_instance {
 	u16 channels;
 	u32 xfer_resolution;
 	struct page *pg;
+	u64 bytescount;
 	void __iomem *acp3x_base;
 };
 
@@ -317,6 +318,24 @@ static int acp3x_dma_open(struct snd_pcm_substream *substream)
 	return 0;
 }
 
+static u64 acp_get_byte_count(struct i2s_stream_instance *rtd, int direction)
+{
+	u64 byte_count;
+
+	if (direction == SNDRV_PCM_STREAM_PLAYBACK) {
+		byte_count = rv_readl(rtd->acp3x_base +
+				      mmACP_BT_TX_LINEARPOSITIONCNTR_HIGH);
+		byte_count |= rv_readl(rtd->acp3x_base +
+				       mmACP_BT_TX_LINEARPOSITIONCNTR_LOW);
+	} else {
+		byte_count = rv_readl(rtd->acp3x_base +
+				      mmACP_BT_RX_LINEARPOSITIONCNTR_HIGH);
+		byte_count |= rv_readl(rtd->acp3x_base +
+				       mmACP_BT_RX_LINEARPOSITIONCNTR_LOW);
+	}
+	return byte_count;
+}
+
 static int acp3x_dma_hw_params(struct snd_pcm_substream *substream,
 			       struct snd_pcm_hw_params *params)
 {
@@ -350,18 +369,17 @@ static int acp3x_dma_hw_params(struct snd_pcm_substream *substream,
 static snd_pcm_uframes_t acp3x_dma_pointer(struct snd_pcm_substream *substream)
 {
 	u32 pos = 0;
-	struct i2s_stream_instance *rtd = substream->runtime->private_data;
-
-	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-		pos = rv_readl(rtd->acp3x_base +
-			       mmACP_BT_TX_LINKPOSITIONCNTR);
-	else
-		pos = rv_readl(rtd->acp3x_base +
-			       mmACP_BT_RX_LINKPOSITIONCNTR);
-
-	if (pos >= MAX_BUFFER)
-		pos = 0;
-
+	u32 buffersize = 0;
+	u64 bytescount = 0;
+	struct i2s_stream_instance *rtd =
+		substream->runtime->private_data;
+
+	buffersize = frames_to_bytes(substream->runtime,
+				     substream->runtime->buffer_size);
+	bytescount = acp_get_byte_count(rtd, substream->stream);
+	if (bytescount > rtd->bytescount)
+		bytescount -= rtd->bytescount;
+	pos = do_div(bytescount, buffersize);
 	return bytes_to_frames(substream->runtime, pos);
 }
 
@@ -521,6 +539,7 @@ static int acp3x_dai_i2s_trigger(struct snd_pcm_substream *substream,
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		rtd->bytescount = acp_get_byte_count(rtd, substream->stream);
 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 			rv_writel(period_bytes, rtd->acp3x_base +
 				  mmACP_BT_TX_INTR_WATERMARK_SIZE);
-- 
2.7.4