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

["Mukunda,Vijendar" <vijendar.mukunda@amd.com>]

On 27/02/23 22:37, Pierre-Louis Bossart wrote:
>
> 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/
you missed my mail in reply thread. That's why we couldn't
get a chance to check your review comments.
>
>> ---
>>  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);
>> +
    will fix inverting above two lines.
>> +	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;
This will break when multiple peripheral devices connected
over the same link and any of the peripheral devices is active.
As amd_resume_child_device() will check for each peripheral
device on the bus. We want to resume peripheral devices,
which are runtime suspended. Rest of it, it should return 0
so that it could continue the iteration for the bus.

The other way we can fix it by always return 0 from
amd_resume_child_device(). In this case no need to check
whether device is runtime suspended or not.
>> +	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.
will check.
>> +		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;
will fix it.
>> +	} 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)
>>  };
>>