Re: [PATCH V4 8/8] soundwire: amd: add pm_prepare callback and pm ops support

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 2/27/23 10:48, Vijendar Mukunda wrote:
> Add pm_prepare callback and System level pm ops support for
> AMD SoundWire manager driver.
> 
> Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
> Signed-off-by: Mastan Katragadda <Mastan.Katragadda@amd.com>

seems like you missed my comments in
https://lore.kernel.org/alsa-devel/7d32d552-6ca0-3c40-11ce-c8d727cadc05@linux.intel.com/

> ---
>  drivers/soundwire/amd_manager.c | 89 +++++++++++++++++++++++++++++++++
>  1 file changed, 89 insertions(+)
> 
> diff --git a/drivers/soundwire/amd_manager.c b/drivers/soundwire/amd_manager.c
> index 88f0ad7ea7ec..5337443d9aea 100644
> --- a/drivers/soundwire/amd_manager.c
> +++ b/drivers/soundwire/amd_manager.c
> @@ -1141,6 +1141,93 @@ static int amd_sdw_clock_stop_exit(struct amd_sdw_manager *amd_manager)
>  	return 0;
>  }
>  
> +static int amd_resume_child_device(struct device *dev, void *data)
> +{
> +	int ret;
> +	struct sdw_slave *slave = dev_to_sdw_dev(dev);
> +
> +	if (!slave->probed) {
> +		dev_dbg(dev, "skipping device, no probed driver\n");
> +		return 0;
> +	}
> +	if (!slave->dev_num_sticky) {
> +		dev_dbg(dev, "skipping device, never detected on bus\n");
> +		return 0;
> +	}
> +	if (!pm_runtime_suspended(dev))
> +		return 0;
> +	ret = pm_request_resume(dev);

I think it's just better to let the pm_runtime framework deal with the
states than do this is two steps.

> +	if (ret < 0)
> +		dev_err(dev, "pm_request_resume failed: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int __maybe_unused amd_pm_prepare(struct device *dev)
> +{
> +	struct amd_sdw_manager *amd_manager = dev_get_drvdata(dev);
> +	struct sdw_bus *bus = &amd_manager->bus;
> +	int ret;
> +
> +	if (bus->prop.hw_disabled) {
> +		dev_dbg(bus->dev, "SoundWire manager %d is disabled, ignoring\n",
> +			bus->link_id);
> +		return 0;
> +	}
> +	/*
> +	 * When multiple peripheral devices connected over the same link, if SoundWire manager
> +	 * device is not in runtime suspend state, observed that device alerts are missing
> +	 * without pm_prepare on AMD platforms in clockstop mode0.
> +	 */
> +	if (pm_runtime_suspended(dev) && amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
> +		ret = pm_request_resume(dev);

same here.

> +		if (ret < 0) {
> +			dev_err(bus->dev, "pm_request_resume failed: %d\n", ret);
> +			return 0;
> +		}
> +	}
> +	/* To force peripheral devices to system level suspend state, resume the devices
> +	 * from runtime suspend state first. Without that unable to dispatch the alert
> +	 * status to peripheral driver during system level resume as they are in runtime
> +	 * suspend state.
> +	 */
> +	ret = device_for_each_child(bus->dev, NULL, amd_resume_child_device);
> +	if (ret < 0)
> +		dev_err(dev, "amd_resume_child_device failed: %d\n", ret);
> +	return 0;
> +}
> +
> +static int __maybe_unused amd_suspend(struct device *dev)
> +{
> +	struct amd_sdw_manager *amd_manager = dev_get_drvdata(dev);
> +	struct sdw_bus *bus = &amd_manager->bus;
> +	int ret;
> +
> +	if (bus->prop.hw_disabled) {
> +		dev_dbg(bus->dev, "SoundWire manager %d is disabled, ignoring\n",
> +			bus->link_id);
> +		return 0;
> +	}
> +
> +	if (amd_manager->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
> +		ret = amd_sdw_clock_stop(amd_manager);
> +		if (ret)
> +			return ret;
> +	} else if (amd_manager->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
> +		/*
> +		 * As per hardware programming sequence on AMD platforms,
> +		 * clock stop should be invoked first before powering-off
> +		 */
> +		ret = amd_sdw_clock_stop(amd_manager);
> +		if (ret)
> +			return ret;
> +		ret = amd_deinit_sdw_manager(amd_manager);
> +		if (ret)
> +			return ret;
> +	}
> +	return 0;
> +}
> +
>  static int __maybe_unused amd_suspend_runtime(struct device *dev)
>  {
>  	struct amd_sdw_manager *amd_manager = dev_get_drvdata(dev);
> @@ -1213,6 +1300,8 @@ static int __maybe_unused amd_resume_runtime(struct device *dev)
>  }
>  
>  static const struct dev_pm_ops amd_pm = {
> +	.prepare = amd_pm_prepare,
> +	SET_SYSTEM_SLEEP_PM_OPS(amd_suspend, amd_resume_runtime)
>  	SET_RUNTIME_PM_OPS(amd_suspend_runtime, amd_resume_runtime, NULL)
>  };
>