diff mbox series

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

Message ID 20230214161435.1088246-2-claudiu.beznea@microchip.com
State New
Headers
Series ASoC: mchp-pdmc: fix poc noises when starting capture |

Commit Message

Claudiu Beznea Feb. 14, 2023, 4:14 p.m. UTC 
  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@microchip.com>
---
 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(-)

Comments

Lars-Peter Clausen Feb. 14, 2023, 6:14 p.m. UTC | #1 
On 2/14/23 08:14, Claudiu Beznea wrote:
> 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;

This will break if you have multiple sound cards in the system. 
dmaengine_pcm_component must stay const.
Mark Brown Feb. 14, 2023, 9:26 p.m. UTC | #2 
On Tue, Feb 14, 2023 at 10:14:28AM -0800, Lars-Peter Clausen wrote:
> On 2/14/23 08:14, Claudiu Beznea wrote:

> > @@ -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;

> This will break if you have multiple sound cards in the system.
> dmaengine_pcm_component must stay const.

Right, if we need to modify it we either need to select which of
multiple const structs to register or to take a copy and modify
that.  I've not looked at the actual changes yet.
Claudiu Beznea Feb. 16, 2023, 9:49 a.m. UTC | #3 
On 14.02.2023 23:26, Mark Brown wrote:
> On Tue, Feb 14, 2023 at 10:14:28AM -0800, Lars-Peter Clausen wrote:
>> On 2/14/23 08:14, Claudiu Beznea wrote:
>>> @@ -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;
>> This will break if you have multiple sound cards in the system.
>> dmaengine_pcm_component must stay const.
> Right, if we need to modify it we either need to select which of
> multiple const structs to register or to take a copy and modify
> that.  I've not looked at the actual changes yet.

OK, I will try that and return with a new patch.

On the other hand do you think the other solution presented in cover letter
would be better? From the cover letter:

"The other solution that was identified for this was to extend the already
existing mechanism around struct snd_soc_dai_link::stop_dma_first. The downside
of this was that a potential struct snd_soc_dai_link::start_dma_last
would have to be populated on sound card driver thus, had to be taken
into account in all sound card drivers. At the moment, the mchp-pdmc is
used only with simple-audio-card. In case of simple-audio-card a new DT
binding would had to be introduced to specify this action on dai-link
descriptions (as of my investigation)."

Thank you,
Claudiu
Lars-Peter Clausen Feb. 16, 2023, 1:53 p.m. UTC | #4 
On 2/16/23 01:49, Claudiu.Beznea@microchip.com wrote:
> On 14.02.2023 23:26, Mark Brown wrote:
>> On Tue, Feb 14, 2023 at 10:14:28AM -0800, Lars-Peter Clausen wrote:
>>> On 2/14/23 08:14, Claudiu Beznea wrote:
>>>> @@ -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;
>>> This will break if you have multiple sound cards in the system.
>>> dmaengine_pcm_component must stay const.
>> Right, if we need to modify it we either need to select which of
>> multiple const structs to register or to take a copy and modify
>> that.  I've not looked at the actual changes yet.
> OK, I will try that and return with a new patch.
>
> On the other hand do you think the other solution presented in cover letter
> would be better? From the cover letter:
>
> "The other solution that was identified for this was to extend the already
> existing mechanism around struct snd_soc_dai_link::stop_dma_first. The downside
> of this was that a potential struct snd_soc_dai_link::start_dma_last
> would have to be populated on sound card driver thus, had to be taken
> into account in all sound card drivers. At the moment, the mchp-pdmc is
> used only with simple-audio-card. In case of simple-audio-card a new DT
> binding would had to be introduced to specify this action on dai-link
> descriptions (as of my investigation)."
>
Can't you just set `start_dma_last` on the `mchp_pdmc_dai_component`? In 
your code you iterate over all the components of the link and if any of 
them has it set the DMA is started last.
Claudiu Beznea Feb. 17, 2023, 10:59 a.m. UTC | #5 
On 16.02.2023 15:53, Lars-Peter Clausen wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> content is safe
> 
> On 2/16/23 01:49, Claudiu.Beznea@microchip.com wrote:
>> On 14.02.2023 23:26, Mark Brown wrote:
>>> On Tue, Feb 14, 2023 at 10:14:28AM -0800, Lars-Peter Clausen wrote:
>>>> On 2/14/23 08:14, Claudiu Beznea wrote:
>>>>> @@ -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;
>>>> This will break if you have multiple sound cards in the system.
>>>> dmaengine_pcm_component must stay const.
>>> Right, if we need to modify it we either need to select which of
>>> multiple const structs to register or to take a copy and modify
>>> that.  I've not looked at the actual changes yet.
>> OK, I will try that and return with a new patch.
>>
>> On the other hand do you think the other solution presented in cover letter
>> would be better? From the cover letter:
>>
>> "The other solution that was identified for this was to extend the already
>> existing mechanism around struct snd_soc_dai_link::stop_dma_first. The
>> downside
>> of this was that a potential struct snd_soc_dai_link::start_dma_last
>> would have to be populated on sound card driver thus, had to be taken
>> into account in all sound card drivers. At the moment, the mchp-pdmc is
>> used only with simple-audio-card. In case of simple-audio-card a new DT
>> binding would had to be introduced to specify this action on dai-link
>> descriptions (as of my investigation)."
>>
> Can't you just set `start_dma_last` on the `mchp_pdmc_dai_component`? In
> your code you iterate over all the components of the link and if any of
> them has it set the DMA is started last.

Yes, that is also working.

In this patch I chose to have it on DMA component as the operation is
specific to DMA... It looked better to me this way. But is true that having
it on mchp_pdmc_dai_component wouldn't affect the behavior.

Thank you,
Claudiu
diff mbox series

Patch

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;