Re: [RFC PATCH 09/14] ASoC: qcom: Add ability to handle interrupts per dma channel

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 03/05/15 01:00, Kenneth Westfield wrote:
> On Thu, Apr 30, 2015 at 06:17:42PM +0100, Srinivas Kandagatla wrote:
>> This patch adds ablity to lpass driver to handle interrupt per dma
>> channel. Without this patch its not possible to use multipl ports on the
>> lpass.
>
>> diff --git a/sound/soc/qcom/lpass-platform.c b/sound/soc/qcom/lpass-platform.c
>> index 8ab0ac1..c5907d5 100644
>> --- a/sound/soc/qcom/lpass-platform.c
>> +++ b/sound/soc/qcom/lpass-platform.c
>
>> -static irqreturn_t lpass_platform_lpaif_irq(int irq, void *data)
>> +static irqreturn_t lpass_dma_interrupt_handler(
>> +			struct snd_pcm_substream *substream,
>> +			struct lpass_data *drvdata,
>> +			int chan, u32 interrupts)
>>   {
>> -	struct snd_pcm_substream *substream = data;
>>   	struct snd_soc_pcm_runtime *soc_runtime = substream->private_data;
>> -	struct lpass_data *drvdata =
>> -		snd_soc_platform_get_drvdata(soc_runtime->platform);
>>   	struct lpass_variant *v = drvdata->variant;
>> -	struct lpass_pcm_data *pcm_data = snd_soc_pcm_get_drvdata(soc_runtime);
>> -	unsigned int interrupts;
>>   	irqreturn_t ret = IRQ_NONE;
>> -	int rv, chan = pcm_data->rdma_ch;
>> -
>> -	rv = regmap_read(drvdata->lpaif_map,
>> -			LPAIF_IRQSTAT_REG(v, LPAIF_IRQ_PORT_HOST), &interrupts);
>> -	if (rv) {
>> -		dev_err(soc_runtime->dev, "%s() error reading from irqstat reg: %d\n",
>> -				__func__, rv);
>> -		return IRQ_NONE;
>> -	}
>> -
>> -	interrupts &= LPAIF_IRQ_ALL(chan);
>> +	int rv;
>>
>>   	if (interrupts & LPAIF_IRQ_PER(chan)) {
>>   		rv = regmap_write(drvdata->lpaif_map,
>> @@ -422,6 +410,30 @@ static irqreturn_t lpass_platform_lpaif_irq(int irq, void *data)
>>   	return ret;
>
> You are returning the ISR result here...
>
>>   }
>>
>> +static irqreturn_t lpass_platform_lpaif_irq(int irq, void *data)
>> +{
>> +	struct lpass_data *drvdata = data;
>> +	struct lpass_variant *v = drvdata->variant;
>> +	unsigned int irqs;
>> +	int rv, chan;
>> +
>> +	rv = regmap_read(drvdata->lpaif_map,
>> +			LPAIF_IRQSTAT_REG(v, LPAIF_IRQ_PORT_HOST), &irqs);
>> +	if (rv) {
>> +		pr_err("%s() error reading from irqstat reg: %d\n",
>> +				__func__, rv);
>> +		return IRQ_NONE;
>> +	}
>> +
>> +	/* Handle per channel interrupts */
>> +	for (chan = 0; chan < LPASS_MAX_DMA_CHANNELS; chan++)
>> +		if (irqs & LPAIF_IRQ_ALL(chan) && drvdata->substream[chan])
>> +			lpass_dma_interrupt_handler(drvdata->substream[chan],
>> +						    drvdata, chan, irqs);
>
> ...but ignoring the result here and always returning HANDLED.
>
That's correct, I will fix this in next version.

>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>
>>   int asoc_qcom_lpass_platform_register(struct platform_device *pdev)
>>   {
>>   	struct lpass_data *drvdata = platform_get_drvdata(pdev);
>> +	struct lpass_variant *v = drvdata->variant;
>> +	int ret;
>>
>>   	drvdata->lpaif_irq = platform_get_irq_byname(pdev, "lpass-irq-lpaif");
>>   	if (drvdata->lpaif_irq < 0) {
>> @@ -553,6 +553,25 @@ int asoc_qcom_lpass_platform_register(struct platform_device *pdev)
>>   		return -ENODEV;
>>   	}
>>
>> +	ret = devm_request_irq(&pdev->dev, drvdata->lpaif_irq,
>> +			lpass_platform_lpaif_irq, IRQF_TRIGGER_RISING,
>> +			"lpass-irq-lpaif", drvdata);
>> +	if (ret) {
>> +		dev_err(&pdev->dev, "%s() irq request failed: %d\n",
>> +				__func__, ret);
>> +		return ret;
>> +	}
>> +
>> +	/* ensure audio hardware is disabled */
>> +	ret = regmap_write(drvdata->lpaif_map,
>> +			LPAIF_IRQEN_REG(v, LPAIF_IRQ_PORT_HOST), 0);
>> +	if (ret) {
>> +		dev_err(&pdev->dev, "%s() error writing to irqen reg: %d\n",
>> +				__func__, ret);
>> +		return ret;
>> +	}
>
> Looking at this, it may be safer to disable the interrupt sources before
> getting/enabling the interrupt, i.e. do the regmap_write first, then
> devm_request_irq.
Yes, Its not safe, will fix it in next version too.

--srini
>