On 11/01/23 21:28, Pierre-Louis Bossart wrote:
>
> On 1/11/23 03:02, Vijendar Mukunda wrote:
>> Add pm_prepare callback and System level pm ops support for
>> AMD master driver.
>>
>> Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@xxxxxxx>
>> Signed-off-by: Mastan Katragadda <Mastan.Katragadda@xxxxxxx>
>> ---
>> drivers/soundwire/amd_master.c | 76 ++++++++++++++++++++++++++++++++++
>> 1 file changed, 76 insertions(+)
>>
>> diff --git a/drivers/soundwire/amd_master.c b/drivers/soundwire/amd_master.c
>> index 2fd77a673c22..f4478cc17aac 100644
>> --- a/drivers/soundwire/amd_master.c
>> +++ b/drivers/soundwire/amd_master.c
>> @@ -1552,6 +1552,80 @@ static int amd_sdwc_clock_stop_exit(struct amd_sdwc_ctrl *ctrl)
>> 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);
>> + if (ret < 0)
>> + dev_err(dev, "%s: pm_request_resume failed: %d\n", __func__, ret);
>> +
>> + return ret;
>> +}
>> +
>> +static int __maybe_unused amd_pm_prepare(struct device *dev)
>> +{
>> + struct amd_sdwc_ctrl *ctrl = dev_get_drvdata(dev);
>> + struct sdw_bus *bus = &ctrl->bus;
>> + int ret;
>> +
>> + if (bus->prop.hw_disabled || !ctrl->startup_done) {
>> + dev_dbg(bus->dev, "SoundWire master %d is disabled or not-started, ignoring\n",
>> + bus->link_id);
>> + return 0;
>> + }
>> + ret = device_for_each_child(bus->dev, NULL, amd_resume_child_device);
>> + if (ret < 0)
>> + dev_err(dev, "%s: amd_resume_child_device failed: %d\n", __func__, ret);
>> + if (pm_runtime_suspended(dev) && ctrl->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
>> + ret = pm_request_resume(dev);
>> + if (ret < 0) {
>> + dev_err(bus->dev, "pm_request_resume failed: %d\n", ret);
>> + return 0;
>> + }
>> + }
>> + return 0;
>> +}
> This seems to be inspired by the Intel code, but is this necessary here?
No It's not inspired by intel code. Initially, we haven't included
pm_prepare callback. We have observed issues without
pm_prepare callback.
> For Intel, we saw cases where we had to pm_resume before doing a system
> suspend, otherwise the hardware was in a bad state.
>
> Do you actually need to do so, or is is possible to do a system suspend
> when the clock is stopped.
>
> And in the case where the bus is in 'power-off' mode, do you actually
> need to resume at all?
Our platform supports different power modes. To support all
combinations, we have included pm_prepare callback.
>> +
>> +static int __maybe_unused amd_suspend(struct device *dev)
>> +{
>> + struct amd_sdwc_ctrl *ctrl = dev_get_drvdata(dev);
>> + struct sdw_bus *bus = &ctrl->bus;
>> + int ret;
>> +
>> + if (bus->prop.hw_disabled || !ctrl->startup_done) {
>> + dev_dbg(bus->dev, "SoundWire master %d is disabled or not-started, ignoring\n",
>> + bus->link_id);
>> + return 0;
>> + }
>> +
>> + if (ctrl->power_mode_mask & AMD_SDW_CLK_STOP_MODE) {
>> + ret = amd_sdwc_clock_stop(ctrl);
>> + if (ret)
>> + return ret;
>> + } else if (ctrl->power_mode_mask & AMD_SDW_POWER_OFF_MODE) {
>> + ret = amd_sdwc_clock_stop(ctrl);
> do you actually need to stop the clock before powering-off? This seems
> counter intuitive and not so useful?
Yes, as per our design, we need to stop the clock
before powering off.
>> + if (ret)
>> + return ret;
>> + ret = amd_deinit_sdw_controller(ctrl);
>> + if (ret)
>> + return ret;
>> + }
>> + return 0;
>> +}
>> +
>> static int __maybe_unused amd_suspend_runtime(struct device *dev)
>> {
>> struct amd_sdwc_ctrl *ctrl = dev_get_drvdata(dev);
>> @@ -1638,6 +1712,8 @@ 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)
>> };
>>
