[PATCH 1/3] ASoC: AMD: Make ACP->SYSMEM DMA non circular

[PATCH 1/3] ASoC: AMD: Make ACP->SYSMEM DMA non circular

[Akshu Agrawal]

In capture case we don't want ACP to SYSMEM dma
to be circular. This is because if an in place DSP
filter is applied to captured output then circular DMA
can overwrite the filter value with stale data.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
---
 sound/soc/amd/acp-pcm-dma.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c
index 94bcf69..816abd6 100644
--- a/sound/soc/amd/acp-pcm-dma.c
+++ b/sound/soc/amd/acp-pcm-dma.c
@@ -400,7 +400,7 @@ static void acp_dma_cap_channel_disable(void __iomem *acp_mmio,
 }
 
 /* Start a given DMA channel transfer */
-static void acp_dma_start(void __iomem *acp_mmio, u16 ch_num)
+static void acp_dma_start(void __iomem *acp_mmio, u16 ch_num, bool is_circular)
 {
 	u32 dma_ctrl;
 
@@ -429,8 +429,11 @@ static void acp_dma_start(void __iomem *acp_mmio, u16 ch_num)
 		break;
 	}
 
-	/* circular for both DMA channel */
-	dma_ctrl |= ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
+	/* enable for ACP to SRAM DMA channel */
+	if (is_circular == true)
+		dma_ctrl |= ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
+	else
+		dma_ctrl &= ~ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
 
 	acp_reg_write(dma_ctrl, acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
 }
@@ -674,6 +677,7 @@ static int acp_deinit(void __iomem *acp_mmio)
 /* ACP DMA irq handler routine for playback, capture usecases */
 static irqreturn_t dma_irq_handler(int irq, void *arg)
 {
+	u16 dscr_idx;
 	u32 intr_flag, ext_intr_status;
 	struct audio_drv_data *irq_data;
 	void __iomem *acp_mmio;
@@ -705,6 +709,15 @@ static irqreturn_t dma_irq_handler(int irq, void *arg)
 
 	if ((intr_flag & BIT(I2S_TO_ACP_DMA_CH_NUM)) != 0) {
 		valid_irq = true;
+		if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_14) ==
+				CAPTURE_START_DMA_DESCR_CH15)
+			dscr_idx = CAPTURE_END_DMA_DESCR_CH14;
+		else
+			dscr_idx = CAPTURE_START_DMA_DESCR_CH14;
+		config_acp_dma_channel(acp_mmio, ACP_TO_SYSRAM_CH_NUM, dscr_idx,
+				       1, 0);
+		acp_dma_start(acp_mmio, ACP_TO_SYSRAM_CH_NUM, false);
+
 		snd_pcm_period_elapsed(irq_data->capture_i2ssp_stream);
 		acp_reg_write((intr_flag & BIT(I2S_TO_ACP_DMA_CH_NUM)) << 16,
 			      acp_mmio, mmACP_EXTERNAL_INTR_STAT);
@@ -712,6 +725,17 @@ static irqreturn_t dma_irq_handler(int irq, void *arg)
 
 	if ((intr_flag & BIT(I2S_TO_ACP_DMA_BT_INSTANCE_CH_NUM)) != 0) {
 		valid_irq = true;
+		if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_10) ==
+			CAPTURE_START_DMA_DESCR_CH11)
+			dscr_idx = CAPTURE_END_DMA_DESCR_CH10;
+		else
+			dscr_idx = CAPTURE_START_DMA_DESCR_CH10;
+		config_acp_dma_channel(acp_mmio,
+				       ACP_TO_SYSRAM_BT_INSTANCE_CH_NUM,
+				       dscr_idx, 1, 0);
+		acp_dma_start(acp_mmio, ACP_TO_SYSRAM_BT_INSTANCE_CH_NUM,
+			      false);
+
 		snd_pcm_period_elapsed(irq_data->capture_i2sbt_stream);
 		acp_reg_write((intr_flag &
 			      BIT(I2S_TO_ACP_DMA_BT_INSTANCE_CH_NUM)) << 16,
@@ -1053,9 +1077,11 @@ static int acp_dma_trigger(struct snd_pcm_substream *substream, int cmd)
 				acp_dma_cap_channel_enable(rtd->acp_mmio,
 							   CAP_CHANNEL1);
 			}
+			acp_dma_start(rtd->acp_mmio, rtd->ch1, true);
+		} else {
+			acp_dma_start(rtd->acp_mmio, rtd->ch1, true);
+			acp_dma_start(rtd->acp_mmio, rtd->ch2, true);
 		}
-		acp_dma_start(rtd->acp_mmio, rtd->ch1);
-		acp_dma_start(rtd->acp_mmio, rtd->ch2);
 		ret = 0;
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
-- 
1.9.1

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

[Akshu Agrawal]

From: "Mukunda, Vijendar" <Vijendar.Mukunda@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@amd.com>
Signed-off-by: Akshu Agrawal <akshu.agrawal@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

Applied "ASoC: AMD: Modified DMA pointer for capture" to the asoc tree

[Mark Brown]

The patch

   ASoC: AMD: Modified DMA pointer for capture

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

From 662fb3efe7ee835f0eeba6bc63b81e82a97fc312 Mon Sep 17 00:00:00 2001
From: "Mukunda, Vijendar" <Vijendar.Mukunda@amd.com>
Date: Mon, 6 Aug 2018 12:57:15 +0530
Subject: [PATCH] ASoC: AMD: Modified DMA pointer for capture

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@amd.com>
Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 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 816abd65a6ed..32f27c5e4d93 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 0a2240bff62e..be3963e8f4fa 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;
-- 
2.18.0

[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@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

Applied "ASoC: AMD: Set delay value for the capture case" to the asoc tree

[Mark Brown]

The patch

   ASoC: AMD: Set delay value for the capture case

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

From c21c834adb5bc81e7081aa93ac50619c6d060506 Mon Sep 17 00:00:00 2001
From: Akshu Agrawal <akshu.agrawal@amd.com>
Date: Mon, 6 Aug 2018 12:57:16 +0530
Subject: [PATCH] ASoC: AMD: Set delay value for the capture case

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@amd.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 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 32f27c5e4d93..e359938e3d7e 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);
-- 
2.18.0

[PATCH 1/3] ASoC: AMD: Make ACP->SYSMEM DMA non circular

[Akshu Agrawal]

In capture case we don't want ACP to SYSMEM dma
to be circular. This is because if an in place DSP
filter is applied to captured output then circular DMA
can overwrite the filter value with stale data.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
---
 sound/soc/amd/acp-pcm-dma.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c
index 94bcf69..816abd6 100644
--- a/sound/soc/amd/acp-pcm-dma.c
+++ b/sound/soc/amd/acp-pcm-dma.c
@@ -400,7 +400,7 @@ static void acp_dma_cap_channel_disable(void __iomem *acp_mmio,
 }
 
 /* Start a given DMA channel transfer */
-static void acp_dma_start(void __iomem *acp_mmio, u16 ch_num)
+static void acp_dma_start(void __iomem *acp_mmio, u16 ch_num, bool is_circular)
 {
 	u32 dma_ctrl;
 
@@ -429,8 +429,11 @@ static void acp_dma_start(void __iomem *acp_mmio, u16 ch_num)
 		break;
 	}
 
-	/* circular for both DMA channel */
-	dma_ctrl |= ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
+	/* enable for ACP to SRAM DMA channel */
+	if (is_circular == true)
+		dma_ctrl |= ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
+	else
+		dma_ctrl &= ~ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
 
 	acp_reg_write(dma_ctrl, acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
 }
@@ -674,6 +677,7 @@ static int acp_deinit(void __iomem *acp_mmio)
 /* ACP DMA irq handler routine for playback, capture usecases */
 static irqreturn_t dma_irq_handler(int irq, void *arg)
 {
+	u16 dscr_idx;
 	u32 intr_flag, ext_intr_status;
 	struct audio_drv_data *irq_data;
 	void __iomem *acp_mmio;
@@ -705,6 +709,15 @@ static irqreturn_t dma_irq_handler(int irq, void *arg)
 
 	if ((intr_flag & BIT(I2S_TO_ACP_DMA_CH_NUM)) != 0) {
 		valid_irq = true;
+		if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_14) ==
+				CAPTURE_START_DMA_DESCR_CH15)
+			dscr_idx = CAPTURE_END_DMA_DESCR_CH14;
+		else
+			dscr_idx = CAPTURE_START_DMA_DESCR_CH14;
+		config_acp_dma_channel(acp_mmio, ACP_TO_SYSRAM_CH_NUM, dscr_idx,
+				       1, 0);
+		acp_dma_start(acp_mmio, ACP_TO_SYSRAM_CH_NUM, false);
+
 		snd_pcm_period_elapsed(irq_data->capture_i2ssp_stream);
 		acp_reg_write((intr_flag & BIT(I2S_TO_ACP_DMA_CH_NUM)) << 16,
 			      acp_mmio, mmACP_EXTERNAL_INTR_STAT);
@@ -712,6 +725,17 @@ static irqreturn_t dma_irq_handler(int irq, void *arg)
 
 	if ((intr_flag & BIT(I2S_TO_ACP_DMA_BT_INSTANCE_CH_NUM)) != 0) {
 		valid_irq = true;
+		if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_10) ==
+			CAPTURE_START_DMA_DESCR_CH11)
+			dscr_idx = CAPTURE_END_DMA_DESCR_CH10;
+		else
+			dscr_idx = CAPTURE_START_DMA_DESCR_CH10;
+		config_acp_dma_channel(acp_mmio,
+				       ACP_TO_SYSRAM_BT_INSTANCE_CH_NUM,
+				       dscr_idx, 1, 0);
+		acp_dma_start(acp_mmio, ACP_TO_SYSRAM_BT_INSTANCE_CH_NUM,
+			      false);
+
 		snd_pcm_period_elapsed(irq_data->capture_i2sbt_stream);
 		acp_reg_write((intr_flag &
 			      BIT(I2S_TO_ACP_DMA_BT_INSTANCE_CH_NUM)) << 16,
@@ -1053,9 +1077,11 @@ static int acp_dma_trigger(struct snd_pcm_substream *substream, int cmd)
 				acp_dma_cap_channel_enable(rtd->acp_mmio,
 							   CAP_CHANNEL1);
 			}
+			acp_dma_start(rtd->acp_mmio, rtd->ch1, true);
+		} else {
+			acp_dma_start(rtd->acp_mmio, rtd->ch1, true);
+			acp_dma_start(rtd->acp_mmio, rtd->ch2, true);
 		}
-		acp_dma_start(rtd->acp_mmio, rtd->ch1);
-		acp_dma_start(rtd->acp_mmio, rtd->ch2);
 		ret = 0;
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
-- 
1.9.1

Re: [PATCH 1/3] ASoC: AMD: Make ACP->SYSMEM DMA non circular

[Mark Brown]

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On Thu, Aug 02, 2018 at 12:11:54PM +0530, Akshu Agrawal wrote:
> In capture case we don't want ACP to SYSMEM dma
> to be circular. This is because if an in place DSP
> filter is applied to captured output then circular DMA
> can overwrite the filter value with stale data.

Isn't that just a problem with userspace not giving itself enough buffer
to get the in place processing done before we loop round again.  This
will simply change the type of error, it won't actually fix anything
AFAICT but perhaps I'm missing something.

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Re: [PATCH 1/3] ASoC: AMD: Make ACP->SYSMEM DMA non circular

[Agrawal, Akshu]

On 8/2/2018 3:26 PM, Mark Brown wrote:
> On Thu, Aug 02, 2018 at 12:11:54PM +0530, Akshu Agrawal wrote:
>> In capture case we don't want ACP to SYSMEM dma
>> to be circular. This is because if an in place DSP
>> filter is applied to captured output then circular DMA
>> can overwrite the filter value with stale data.
> 
> Isn't that just a problem with userspace not giving itself enough buffer
> to get the in place processing done before we loop round again.  This
> will simply change the type of error, it won't actually fix anything
> AFAICT but perhaps I'm missing something.
> 

Sorry for the delayed reply. Will try and explain more on whats happening:
We have 2 DMAs, one being I2S->ACP(Audio Co-Processor memory) and the
second being ACP->SYSMEM. When ACP->SYSMEM is circular then this DMA is
faster and keeps updating from ACP memory. This leaves no time for user
space to do any kind of in place post processing. This design works fine
if the user reads the data from SYSMEM at capture rate (that is the rate
at which I2S->ACP transfer happens). But, when an in place post
processing happens on SYSMEM then the data gets overwritten.

Sending and updated series with changes in 2/3 and 3/3 patch.

Thanks,
Akshu