[alsa-devel] [PATCH 04/26] ASoC: SOF: Intel: hda-dsp: Add helper for setting DSP D0ix substate

[Cezary Rojewski]

On 2019-10-26 00:41, Pierre-Louis Bossart wrote:
> From: Keyon Jie <yang.jie at linux.intel.com>
> 
> Adding helper to implement setting dsp to d0i3 or d0i0 status, this will
> be needed for driver D0ix support.
> 
> Signed-off-by: Keyon Jie <yang.jie at linux.intel.com>
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>

> +static int hda_dsp_wait_d0i3c_done(struct snd_sof_dev *sdev, int retry)
> +{
> +	struct hdac_bus *bus = sof_to_bus(sdev);
> +
> +	while (snd_hdac_chip_readb(bus, VS_D0I3C) & SOF_HDA_VS_D0I3C_CIP) {
> +		if (!retry--)
> +			return -ETIMEDOUT;
> +		usleep_range(10, 15);
> +	}
> +
> +	return 0;
> +}
> +
> +int hda_dsp_set_power_state(struct snd_sof_dev *sdev,
> +			    enum sof_d0_substate d0_substate)
> +{
> +	struct hdac_bus *bus = sof_to_bus(sdev);
> +	int retry = 50;
> +	int ret;
> +	u8 value;
> +
> +	/* Write to D0I3C after Command-In-Progress bit is cleared */
> +	ret = hda_dsp_wait_d0i3c_done(sdev, retry);
> +	if (ret < 0) {
> +		dev_err(bus->dev, "CIP timeout before update D0I3C!\n");
> +		return ret;
> +	}
> +
> +	/* Update D0I3C register */
> +	value = d0_substate == SOF_DSP_D0I3 ? SOF_HDA_VS_D0I3C_I3 : 0;

Some indentation or parenthesis would make this cleaner.

> +	snd_hdac_chip_updateb(bus, VS_D0I3C, SOF_HDA_VS_D0I3C_I3, value);
> +
> +	/* Wait for cmd in progress to be cleared before exiting the function */
> +	retry = 50;
> +	ret = hda_dsp_wait_d0i3c_done(sdev, retry);
> +	if (ret < 0) {
> +		dev_err(bus->dev, "CIP timeout after D0I3C updated!\n");
> +		return ret;
> +	}
> +
> +	dev_vdbg(bus->dev, "D0I3C updated, register = 0x%x\n",
> +		 snd_hdac_chip_readb(bus, VS_D0I3C));
> +
> +	return 0;
> +}
> +

I believe hda_dsp_wait_d0i3c_done function could have had its argument 
list simplified. "retry" is passed externally and it is always set to 
50. One could put the "retry" right inside _done function. This or allow 
the caller to modify the sleep period. Another option is to replace 
"retry" with "timeout period" (total timeout, that is) entirely.

In regard to maintenance, both ret checks (resulting in dev_errs) assume 
-ETIMEOUT outcome on _done failure. If said function gets updated in the 
future, these implicit checks might cause problems.

>   static int hda_suspend(struct snd_sof_dev *sdev, bool runtime_suspend)
>   {
>   	struct sof_intel_hda_dev *hda = sdev->pdata->hw_pdata;
> diff --git a/sound/soc/sof/intel/hda.h b/sound/soc/sof/intel/hda.h
> index ea02bf40cb25..0e7c366b8f71 100644
> --- a/sound/soc/sof/intel/hda.h
> +++ b/sound/soc/sof/intel/hda.h
> @@ -64,6 +64,13 @@
>   #define SOF_HDA_PPCTL_PIE		BIT(31)
>   #define SOF_HDA_PPCTL_GPROCEN		BIT(30)
>   
> +/*Vendor Specific Registers*/

Missing spaces.

> +#define SOF_HDA_VS_D0I3C		0x104A