[alsa-devel] [PATCH v2 3/3] ASoC: AMD: Set delay value for the capture case

[Akshu Agrawal]

ACP->SYSMEM DMA happens at every I2S->SYSMEM period
completion. Thus, there is delay of x frames till
I2S->SYSMEM reaches a period length. This delay is
communicated to user space.

Signed-off-by: Akshu Agrawal <akshu.agrawal at amd.com>
---
v2: moved reading of bytes transfered from I2S->ACP to get
more accurate delay information.
 sound/soc/amd/acp-pcm-dma.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c
index 32f27c5..e359938 100644
--- a/sound/soc/amd/acp-pcm-dma.c
+++ b/sound/soc/amd/acp-pcm-dma.c
@@ -922,6 +922,10 @@ 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;
@@ -942,6 +946,10 @@ 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;
 		}
@@ -997,7 +1005,7 @@ static snd_pcm_uframes_t acp_dma_pointer(struct snd_pcm_substream *substream)
 	u32 pos = 0;
 	u64 bytescount = 0;
 	u16 dscr;
-	u32 period_bytes;
+	u32 period_bytes, delay;
 
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct audio_substream_data *rtd = runtime->private_data;
@@ -1012,6 +1020,11 @@ static snd_pcm_uframes_t acp_dma_pointer(struct snd_pcm_substream *substream)
 			pos = period_bytes;
 		else
 			pos = 0;
+		bytescount = acp_get_byte_count(rtd);
+		if (bytescount > rtd->bytescount)
+			bytescount -= rtd->bytescount;
+		delay = do_div(bytescount, period_bytes);
+		runtime->delay = bytes_to_frames(runtime, delay);
 	} else {
 		buffersize = frames_to_bytes(runtime, runtime->buffer_size);
 		bytescount = acp_get_byte_count(rtd);
-- 
1.9.1