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

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.

• 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.