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From:   Akshu Agrawal <akshu.agrawal@amd.com>
Cc:     djkurtz@chromium.org, akshu.agrawal@amd.com,
        Alexander.Deucher@amd.com, Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        "Mukunda, Vijendar" <Vijendar.Mukunda@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Guenter Roeck <linux@roeck-us.net>,
        alsa-devel@alsa-project.org (moderated list:SOUND - SOC LAYER / DYNAMIC
        AUDIO POWER MANAGEM...), linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] ASoC: AMD: make channel 1 dma as circular
Date:   Fri, 25 May 2018 17:22:39 +0800
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channel 1: SYSMEM<->ACP
channel 2: ACP<->I2S
Instead of waiting on period interrupt of ch 2 and then starting
dma on ch1, we make ch1 dma as circular.
This removes dependency of period granularity on hw pointer.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
---
 sound/soc/amd/acp-pcm-dma.c | 72 +++++++--------------------------------------
 1 file changed, 10 insertions(+), 62 deletions(-)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c
index ac32dea..f1d8678 100644
--- a/sound/soc/amd/acp-pcm-dma.c
+++ b/sound/soc/amd/acp-pcm-dma.c
@@ -337,8 +337,7 @@ static void config_acp_dma(void __iomem *acp_mmio,
 }
 
 /* Start a given DMA channel transfer */
-static void acp_dma_start(void __iomem *acp_mmio,
-			  u16 ch_num, bool is_circular)
+static void acp_dma_start(void __iomem *acp_mmio, u16 ch_num)
 {
 	u32 dma_ctrl;
 
@@ -369,11 +368,8 @@ static void acp_dma_start(void __iomem *acp_mmio,
 		break;
 	}
 
-	/* enable  for ACP SRAM to/from I2S 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;
+	/* circular for both DMA channel */
+	dma_ctrl |= ACP_DMA_CNTL_0__Circular_DMA_En_MASK;
 
 	acp_reg_write(dma_ctrl, acp_mmio, mmACP_DMA_CNTL_0 + ch_num);
 }
@@ -617,7 +613,6 @@ 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;
@@ -634,33 +629,13 @@ static irqreturn_t dma_irq_handler(int irq, void *arg)
 
 	if ((intr_flag & BIT(ACP_TO_I2S_DMA_CH_NUM)) != 0) {
 		valid_irq = true;
-		if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_13) ==
-				PLAYBACK_START_DMA_DESCR_CH13)
-			dscr_idx = PLAYBACK_END_DMA_DESCR_CH12;
-		else
-			dscr_idx = PLAYBACK_START_DMA_DESCR_CH12;
-		config_acp_dma_channel(acp_mmio, SYSRAM_TO_ACP_CH_NUM, dscr_idx,
-				       1, 0);
-		acp_dma_start(acp_mmio, SYSRAM_TO_ACP_CH_NUM, false);
-
 		snd_pcm_period_elapsed(irq_data->play_i2ssp_stream);
-
 		acp_reg_write((intr_flag & BIT(ACP_TO_I2S_DMA_CH_NUM)) << 16,
 			      acp_mmio, mmACP_EXTERNAL_INTR_STAT);
 	}
 
 	if ((intr_flag & BIT(ACP_TO_I2S_DMA_BT_INSTANCE_CH_NUM)) != 0) {
 		valid_irq = true;
-		if (acp_reg_read(acp_mmio, mmACP_DMA_CUR_DSCR_9) ==
-			PLAYBACK_START_DMA_DESCR_CH9)
-			dscr_idx = PLAYBACK_END_DMA_DESCR_CH8;
-		else
-			dscr_idx = PLAYBACK_START_DMA_DESCR_CH8;
-		config_acp_dma_channel(acp_mmio,
-				       SYSRAM_TO_ACP_BT_INSTANCE_CH_NUM,
-				       dscr_idx, 1, 0);
-		acp_dma_start(acp_mmio, SYSRAM_TO_ACP_BT_INSTANCE_CH_NUM,
-			      false);
 		snd_pcm_period_elapsed(irq_data->play_i2sbt_stream);
 		acp_reg_write((intr_flag &
 			      BIT(ACP_TO_I2S_DMA_BT_INSTANCE_CH_NUM)) << 16,
@@ -669,38 +644,20 @@ 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_15) ==
-				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);
 	}
 
 	if ((intr_flag & BIT(ACP_TO_SYSRAM_CH_NUM)) != 0) {
 		valid_irq = true;
-		snd_pcm_period_elapsed(irq_data->capture_i2ssp_stream);
 		acp_reg_write((intr_flag & BIT(ACP_TO_SYSRAM_CH_NUM)) << 16,
 			      acp_mmio, mmACP_EXTERNAL_INTR_STAT);
 	}
 
 	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_11) ==
-			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,
 			      acp_mmio, mmACP_EXTERNAL_INTR_STAT);
@@ -708,7 +665,6 @@ static irqreturn_t dma_irq_handler(int irq, void *arg)
 
 	if ((intr_flag & BIT(ACP_TO_SYSRAM_BT_INSTANCE_CH_NUM)) != 0) {
 		valid_irq = true;
-		snd_pcm_period_elapsed(irq_data->capture_i2sbt_stream);
 		acp_reg_write((intr_flag &
 			      BIT(ACP_TO_SYSRAM_BT_INSTANCE_CH_NUM)) << 16,
 			      acp_mmio, mmACP_EXTERNAL_INTR_STAT);
@@ -1015,11 +971,9 @@ static int acp_dma_prepare(struct snd_pcm_substream *substream)
 static int acp_dma_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	int ret;
-	u32 loops = 4000;
 	u64 bytescount = 0;
 
 	struct snd_pcm_runtime *runtime = substream->runtime;
-	struct snd_soc_pcm_runtime *prtd = substream->private_data;
 	struct audio_substream_data *rtd = runtime->private_data;
 	struct snd_soc_component *component = snd_soc_rtdcom_lookup(prtd,
 								    DRV_NAME);
@@ -1034,18 +988,12 @@ static int acp_dma_trigger(struct snd_pcm_substream *substream, int cmd)
 		if (rtd->bytescount == 0)
 			rtd->bytescount = bytescount;
 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
-			acp_dma_start(rtd->acp_mmio, rtd->ch1, false);
-			while (acp_reg_read(rtd->acp_mmio, mmACP_DMA_CH_STS) &
-				BIT(rtd->ch1)) {
-				if (!loops--) {
-					dev_err(component->dev,
-						"acp dma start timeout\n");
-					return -ETIMEDOUT;
-				}
-				cpu_relax();
-			}
+			acp_dma_start(rtd->acp_mmio, rtd->ch1);
+			acp_dma_start(rtd->acp_mmio, rtd->ch2);
+		} else {
+			acp_dma_start(rtd->acp_mmio, rtd->ch2);
+			acp_dma_start(rtd->acp_mmio, rtd->ch1);
 		}
-		acp_dma_start(rtd->acp_mmio, rtd->ch2, true);
 		ret = 0;
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
-- 
1.9.1