linux-kernel - Re: [PATCH V2 6/9] ASoC: amd: ps: add pm ops support for SoundWire dma driver

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Date:   Tue, 23 May 2023 16:23:57 +0530
From:   "Mukunda,Vijendar" <vijendar.mukunda@....com>
To:     Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        broonie@...nel.org
Cc:     alsa-devel@...a-project.org, Basavaraj.Hiregoudar@....com,
        Sunil-kumar.Dommati@....com, Mastan.Katragadda@....com,
        Arungopal.kondaveeti@....com, mario.limonciello@....com,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 6/9] ASoC: amd: ps: add pm ops support for SoundWire
 dma driver

On 22/05/23 23:50, Pierre-Louis Bossart wrote:
>> @@ -464,16 +488,79 @@ static int acp63_sdw_platform_probe(struct platform_device *pdev)
>>  	status = devm_snd_soc_register_component(&pdev->dev,
>>  						 &acp63_sdw_component,
>>  						 NULL, 0);
>> -	if (status)
>> +	if (status) {
>>  		dev_err(&pdev->dev, "Fail to register sdw dma component\n");
>> +		return status;
>> +	}
>> +	pm_runtime_set_autosuspend_delay(&pdev->dev, ACP_SUSPEND_DELAY_MS);
>> +	pm_runtime_use_autosuspend(&pdev->dev);
>> +	pm_runtime_enable(&pdev->dev);
>> +	pm_runtime_allow(&pdev->dev);
> Can you remind me why you need the pm_runtime_allow()? I can't recall
> where the _forbid() is done.
We have used pm_runtime_allow() to allow the device immediately
enter runtime suspend state. Yes you are correct. If we use pm_runtime_allow(),
then in remove sequence we should use pm_runtime_forbid call.
> Also is there not a pm_runtime_set_active() missing?


We will change the sequence as mentioned below.

in probe sequence , we will use

    pm_runtime_set_autosuspend_delay(&pdev->dev, ACP_SUSPEND_DELAY_MS);
    pm_runtime_use_autosuspend(&pdev->dev);
    pm_runtime_mark_last_busy(&pdev->dev);
    pm_runtime_set_active(&pdev->dev);
    pm_runtime_enable(&pdev->dev);

In remove sequence

pm_runtime_disable(&pdev->dev);
>
>> +	return 0;
>> +}
>>  
>> -	return status;
>> +static int acp63_sdw_platform_remove(struct platform_device *pdev)
>> +{
>> +	pm_runtime_disable(&pdev->dev);
>> +	return 0;
>>  }
>>  
>> +static int __maybe_unused acp63_sdw_pcm_resume(struct device *dev)
>> +{
>> +	struct sdw_dma_dev_data *sdw_data;
>> +	struct acp_sdw_dma_stream *stream;
>> +	struct snd_pcm_runtime *runtime;
>> +	u32 period_bytes, buf_size, water_mark_size_reg;
>> +	int ret;
>> +	int index;
>> +
>> +	sdw_data = dev_get_drvdata(dev);
>> +	for (index = 0; index < ACP63_SDW0_DMA_MAX_STREAMS; index++) {
>> +		if (sdw_data->sdw0_dma_stream[index] &&
>> +		    sdw_data->sdw0_dma_stream[index]->runtime) {
>> +			water_mark_size_reg = sdw0_dma_ring_buf_reg[index].water_mark_size_reg;
>> +			runtime = sdw_data->sdw0_dma_stream[index]->runtime;
>> +			stream = runtime->private_data;
>> +			period_bytes = frames_to_bytes(runtime, runtime->period_size);
>> +			buf_size = frames_to_bytes(runtime, runtime->buffer_size);
>> +			acp63_config_dma(stream, sdw_data->acp_base, index);
>> +			ret = acp63_configure_sdw_ringbuffer(sdw_data->acp_base, index,
>> +							     buf_size, ACP_SDW0);
>> +			if (ret)
>> +				return ret;
>> +			writel(period_bytes, sdw_data->acp_base + water_mark_size_reg);
>> +		}
>> +	}
>> +	for (index = 0; index < ACP63_SDW1_DMA_MAX_STREAMS; index++) {
>> +		if (sdw_data->sdw1_dma_stream[index] &&
>> +		    sdw_data->sdw1_dma_stream[index]->runtime) {
>> +			water_mark_size_reg = sdw1_dma_ring_buf_reg[index].water_mark_size_reg;
>> +			runtime = sdw_data->sdw1_dma_stream[index]->runtime;
>> +			stream = runtime->private_data;
>> +			period_bytes = frames_to_bytes(runtime, runtime->period_size);
>> +			buf_size = frames_to_bytes(runtime, runtime->buffer_size);
>> +			acp63_config_dma(stream, sdw_data->acp_base, index);
>> +			ret = acp63_configure_sdw_ringbuffer(sdw_data->acp_base, index,
>> +							     buf_size, ACP_SDW1);
>> +			if (ret)
>> +				return ret;
>> +			writel(period_bytes, sdw_data->acp_base + water_mark_size_reg);
>> +		}
>> +	}
> Isn't this set of configurations something that needs to be done already
> somewhere else, i.e. could there be a common helper?
In hw_params() callback, we are setting period_bytes and buf_size from
params structure. We are extracting same variables from runtime structures
in resume() callback.
We can implement a helper function to further simplify above logic
instead of having two separate loops.
>
>> +	acp63_enable_disable_sdw_dma_interrupts(sdw_data->acp_base, true);
>> +	return 0;
>> +}
>> +
>> +static const struct dev_pm_ops acp63_pm_ops = {
>> +	SET_SYSTEM_SLEEP_PM_OPS(NULL, acp63_sdw_pcm_resume)
>> +};
>> +
>>  static struct platform_driver acp63_sdw_dma_driver = {
>>  	.probe = acp63_sdw_platform_probe,
>> +	.remove = acp63_sdw_platform_remove,
>>  	.driver = {
>>  		.name = "amd_ps_sdw_dma",
>> +		.pm = &acp63_pm_ops,
>>  	},
>>  };
>>