[alsa-devel] [PATCH v2 2/3] ASoC: AMD: Modified DMA pointer for capture

[Akshu Agrawal]

From: "Mukunda, Vijendar" <Vijendar.Mukunda at amd.com>

Give position on ACP->SYSMEM DMA channel for
the number of bytes that have been transferred on
the basis of current descriptor under service.

Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda at amd.com>
Signed-off-by: Akshu Agrawal <akshu.agrawal at amd.com>
---
v2: Fixed position, now position = 0 if on 1st descriptor and
pos = period_bytes if on second descriptor.
 sound/soc/amd/acp-pcm-dma.c | 31 ++++++++++++++++++-------------
 sound/soc/amd/acp.h         |  1 +
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c
index 816abd6..32f27c5 100644
--- a/sound/soc/amd/acp-pcm-dma.c
+++ b/sound/soc/amd/acp-pcm-dma.c
@@ -922,10 +922,7 @@ static int acp_dma_hw_params(struct snd_pcm_substream *substream,
 			rtd->destination = FROM_BLUETOOTH;
 			rtd->dma_dscr_idx_1 = CAPTURE_START_DMA_DESCR_CH10;
 			rtd->dma_dscr_idx_2 = CAPTURE_START_DMA_DESCR_CH11;
-			rtd->byte_cnt_high_reg_offset =
-					mmACP_I2S_BT_RECEIVE_BYTE_CNT_HIGH;
-			rtd->byte_cnt_low_reg_offset =
-					mmACP_I2S_BT_RECEIVE_BYTE_CNT_LOW;
+			rtd->dma_curr_dscr = mmACP_DMA_CUR_DSCR_11;
 			adata->capture_i2sbt_stream = substream;
 			break;
 		case I2S_SP_INSTANCE:
@@ -945,10 +942,7 @@ static int acp_dma_hw_params(struct snd_pcm_substream *substream,
 			rtd->destination = FROM_ACP_I2S_1;
 			rtd->dma_dscr_idx_1 = CAPTURE_START_DMA_DESCR_CH14;
 			rtd->dma_dscr_idx_2 = CAPTURE_START_DMA_DESCR_CH15;
-			rtd->byte_cnt_high_reg_offset =
-					mmACP_I2S_RECEIVED_BYTE_CNT_HIGH;
-			rtd->byte_cnt_low_reg_offset =
-					mmACP_I2S_RECEIVED_BYTE_CNT_LOW;
+			rtd->dma_curr_dscr = mmACP_DMA_CUR_DSCR_15;
 			adata->capture_i2ssp_stream = substream;
 		}
 	}
@@ -1002,6 +996,8 @@ static snd_pcm_uframes_t acp_dma_pointer(struct snd_pcm_substream *substream)
 	u32 buffersize;
 	u32 pos = 0;
 	u64 bytescount = 0;
+	u16 dscr;
+	u32 period_bytes;
 
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct audio_substream_data *rtd = runtime->private_data;
@@ -1009,11 +1005,20 @@ static snd_pcm_uframes_t acp_dma_pointer(struct snd_pcm_substream *substream)
 	if (!rtd)
 		return -EINVAL;
 
-	buffersize = frames_to_bytes(runtime, runtime->buffer_size);
-	bytescount = acp_get_byte_count(rtd);
-
-	bytescount -= rtd->bytescount;
-	pos = do_div(bytescount, buffersize);
+	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
+		period_bytes = frames_to_bytes(runtime, runtime->period_size);
+		dscr = acp_reg_read(rtd->acp_mmio, rtd->dma_curr_dscr);
+		if (dscr == rtd->dma_dscr_idx_1)
+			pos = period_bytes;
+		else
+			pos = 0;
+	} else {
+		buffersize = frames_to_bytes(runtime, runtime->buffer_size);
+		bytescount = acp_get_byte_count(rtd);
+		if (bytescount > rtd->bytescount)
+			bytescount -= rtd->bytescount;
+		pos = do_div(bytescount, buffersize);
+	}
 	return bytes_to_frames(runtime, pos);
 }
 
diff --git a/sound/soc/amd/acp.h b/sound/soc/amd/acp.h
index 0a2240b..be3963e 100644
--- a/sound/soc/amd/acp.h
+++ b/sound/soc/amd/acp.h
@@ -138,6 +138,7 @@ struct audio_substream_data {
 	u32 sram_bank;
 	u32 byte_cnt_high_reg_offset;
 	u32 byte_cnt_low_reg_offset;
+	u32 dma_curr_dscr;
 	uint64_t size;
 	u64 bytescount;
 	void __iomem *acp_mmio;
-- 
1.9.1