[PATCH 1/3] ASoC: soc-generic-dmaengine-pcm: add option to start DMA after DAI

[Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>]

Add option to start DMA component after DAI trigger. This is done
by filling the new struct snd_dmaengine_pcm_config::start_dma_last.

Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
---
 include/sound/dmaengine_pcm.h         |  1 +
 include/sound/soc-component.h         |  2 ++
 sound/soc/soc-generic-dmaengine-pcm.c |  8 +++++---
 sound/soc/soc-pcm.c                   | 27 ++++++++++++++++++++++-----
 4 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h
index 2df54cf02cb3..4e3dcb94576d 100644
--- a/include/sound/dmaengine_pcm.h
+++ b/include/sound/dmaengine_pcm.h
@@ -149,6 +149,7 @@ struct snd_dmaengine_pcm_config {
 
 	const struct snd_pcm_hardware *pcm_hardware;
 	unsigned int prealloc_buffer_size;
+	unsigned int start_dma_last;
 };
 
 int snd_dmaengine_pcm_register(struct device *dev,
diff --git a/include/sound/soc-component.h b/include/sound/soc-component.h
index 3203d35bc8c1..0814ed143864 100644
--- a/include/sound/soc-component.h
+++ b/include/sound/soc-component.h
@@ -190,6 +190,8 @@ struct snd_soc_component_driver {
 	bool use_dai_pcm_id;	/* use DAI link PCM ID as PCM device number */
 	int be_pcm_base;	/* base device ID for all BE PCMs */
 
+	unsigned int start_dma_last;
+
 #ifdef CONFIG_DEBUG_FS
 	const char *debugfs_prefix;
 #endif
diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
index 3b99f619e37e..264e87af6b58 100644
--- a/sound/soc/soc-generic-dmaengine-pcm.c
+++ b/sound/soc/soc-generic-dmaengine-pcm.c
@@ -318,7 +318,7 @@ static int dmaengine_copy_user(struct snd_soc_component *component,
 	return 0;
 }
 
-static const struct snd_soc_component_driver dmaengine_pcm_component = {
+static struct snd_soc_component_driver dmaengine_pcm_component = {
 	.name		= SND_DMAENGINE_PCM_DRV_NAME,
 	.probe_order	= SND_SOC_COMP_ORDER_LATE,
 	.open		= dmaengine_pcm_open,
@@ -329,7 +329,7 @@ static const struct snd_soc_component_driver dmaengine_pcm_component = {
 	.pcm_construct	= dmaengine_pcm_new,
 };
 
-static const struct snd_soc_component_driver dmaengine_pcm_component_process = {
+static struct snd_soc_component_driver dmaengine_pcm_component_process = {
 	.name		= SND_DMAENGINE_PCM_DRV_NAME,
 	.probe_order	= SND_SOC_COMP_ORDER_LATE,
 	.open		= dmaengine_pcm_open,
@@ -425,7 +425,7 @@ static const struct snd_dmaengine_pcm_config snd_dmaengine_pcm_default_config =
 int snd_dmaengine_pcm_register(struct device *dev,
 	const struct snd_dmaengine_pcm_config *config, unsigned int flags)
 {
-	const struct snd_soc_component_driver *driver;
+	struct snd_soc_component_driver *driver;
 	struct dmaengine_pcm *pcm;
 	int ret;
 
@@ -450,6 +450,8 @@ int snd_dmaengine_pcm_register(struct device *dev,
 	else
 		driver = &dmaengine_pcm_component;
 
+	driver->start_dma_last = config->start_dma_last;
+
 	ret = snd_soc_component_initialize(&pcm->component, driver, dev);
 	if (ret)
 		goto err_free_dma;
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 005b179a770a..ec429b93a4ee 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1088,22 +1088,39 @@ static int soc_pcm_hw_params(struct snd_pcm_substream *substream,
 static int soc_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
-	int ret = -EINVAL, _ret = 0;
+	struct snd_soc_component *component;
+	int ret = -EINVAL, _ret = 0, start_dma_last = 0, i;
 	int rollback = 0;
 
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		/* Do we need to start dma first? */
+		for_each_rtd_components(rtd, i, component) {
+			if (component->driver->start_dma_last) {
+				start_dma_last = 1;
+				break;
+			}
+		}
+
 		ret = snd_soc_link_trigger(substream, cmd, 0);
 		if (ret < 0)
 			goto start_err;
 
-		ret = snd_soc_pcm_component_trigger(substream, cmd, 0);
-		if (ret < 0)
-			goto start_err;
+		if (start_dma_last) {
+			ret = snd_soc_pcm_dai_trigger(substream, cmd, 0);
+			if (ret < 0)
+				goto start_err;
+
+			ret = snd_soc_pcm_component_trigger(substream, cmd, 0);
+		} else {
+			ret = snd_soc_pcm_component_trigger(substream, cmd, 0);
+			if (ret < 0)
+				goto start_err;
 
-		ret = snd_soc_pcm_dai_trigger(substream, cmd, 0);
+			ret = snd_soc_pcm_dai_trigger(substream, cmd, 0);
+		}
 start_err:
 		if (ret < 0)
 			rollback = 1;
-- 
2.34.1