[alsa-devel] [PATCH 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>
---
 sound/soc/amd/acp-pcm-dma.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c
index 6240a77..c24611c 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;
 			rtd->cur_trans_cnt = mmACP_DMA_CUR_TRANS_CNT_11;
 			rtd->end_dma_dscr = CAPTURE_END_DMA_DESCR_CH10;
@@ -944,6 +948,10 @@ 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;
 			rtd->cur_trans_cnt = mmACP_DMA_CUR_TRANS_CNT_15;
 			rtd->end_dma_dscr = CAPTURE_END_DMA_DESCR_CH14;
@@ -1002,7 +1010,7 @@ static snd_pcm_uframes_t acp_dma_pointer(struct snd_pcm_substream *substream)
 	u64 bytescount = 0;
 	u32 dma_count = 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;
@@ -1011,6 +1019,10 @@ static snd_pcm_uframes_t acp_dma_pointer(struct snd_pcm_substream *substream)
 		return -EINVAL;
 
 	buffersize = frames_to_bytes(runtime, runtime->buffer_size);
+	bytescount = acp_get_byte_count(rtd);
+	if (bytescount > rtd->bytescount)
+		bytescount -= rtd->bytescount;
+
 	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);
@@ -1018,10 +1030,9 @@ static snd_pcm_uframes_t acp_dma_pointer(struct snd_pcm_substream *substream)
 		if (dscr == rtd->end_dma_dscr)
 			dma_count += period_bytes;
 		pos = dma_count % buffersize;
+		delay = do_div(bytescount, period_bytes);
+		runtime->delay = bytes_to_frames(runtime, delay);
 	} else {
-		bytescount = acp_get_byte_count(rtd);
-		if (bytescount > rtd->bytescount)
-			bytescount -= rtd->bytescount;
 		pos = do_div(bytescount, buffersize);
 	}
 	return bytes_to_frames(runtime, pos);
-- 
1.9.1