Re: [PATCH net-next v5 10/13] net: wwan: t7xx: Introduce power management

["Martinez, Ricardo" <ricardo.martinez@linux.intel.com>]

On 3/1/2022 5:26 AM, Ilpo Järvinen wrote:
> On Wed, 23 Feb 2022, Ricardo Martinez wrote:
>
>> From: Haijun Liu <haijun.liu@mediatek.com>
>>
>> Implements suspend, resumes, freeze, thaw, poweroff, and restore
>> `dev_pm_ops` callbacks.
>>
>> >From the host point of view, the t7xx driver is one entity. But, the
>> device has several modules that need to be addressed in different ways
>> during power management (PM) flows.
>> The driver uses the term 'PM entities' to refer to the 2 DPMA and
>> 2 CLDMA HW blocks that need to be managed during PM flows.
>> When a dev_pm_ops function is called, the PM entities list is iterated
>> and the matching function is called for each entry in the list.
>>
>> Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
>> Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
>> Co-developed-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
>> Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
>> ---
>> +static int __t7xx_pci_pm_suspend(struct pci_dev *pdev)
>> +{
> ...
>> +	iowrite32(L1_DISABLE_BIT(0), IREG_BASE(t7xx_dev) + DIS_ASPM_LOWPWR_CLR_0);
>> +	return 0;
> The success path does this same iowrite32 to DIS_ASPM_LOWPWR_CLR_0
> as the failure paths. Is that intended?

Yes, that's intended.

This function disables low power mode at the beginning and it has to 
re-enable it before

returning, regardless of the success or failure path.

The next iteration will contain some naming changes to avoid double 
negatives :

- iowrite32(L1_DISABLE_BIT(0), IREG_BASE(t7xx_dev) + DIS_ASPM_LOWPWR_CLR_0);

+ iowrite32(T7XX_L1_BIT(0), IREG_BASE(t7xx_dev) + DISABLE_ASPM_LOWPWR);


> The function looks much better now!
>
>