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

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Message-ID: <2493227c-4489-22ac-0561-f52d1de27fec@linux.intel.com>
Date:   Mon, 7 Mar 2022 16:54:13 -0800
From:   "Martinez, Ricardo" <ricardo.martinez@...ux.intel.com>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc:     Netdev <netdev@...r.kernel.org>, linux-wireless@...r.kernel.org,
        kuba@...nel.org, davem@...emloft.net, johannes@...solutions.net,
        ryazanov.s.a@...il.com, loic.poulain@...aro.org,
        m.chetan.kumar@...el.com, chandrashekar.devegowda@...el.com,
        linuxwwan@...el.com, chiranjeevi.rapolu@...ux.intel.com,
        haijun.liu@...iatek.com, amir.hanania@...el.com,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        dinesh.sharma@...el.com, eliot.lee@...el.com,
        moises.veleta@...el.com, pierre-louis.bossart@...el.com,
        muralidharan.sethuraman@...el.com, Soumya.Prakash.Mishra@...el.com,
        sreehari.kancharla@...el.com, madhusmita.sahu@...el.com
Subject: Re: [PATCH net-next v5 10/13] net: wwan: t7xx: Introduce power
 management


On 3/1/2022 5:26 AM, Ilpo Järvinen wrote:
> On Wed, 23 Feb 2022, Ricardo Martinez wrote:
>
>> From: Haijun Liu <haijun.liu@...iatek.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@...iatek.com>
>> Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@...el.com>
>> Co-developed-by: Ricardo Martinez <ricardo.martinez@...ux.intel.com>
>> Signed-off-by: Ricardo Martinez <ricardo.martinez@...ux.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!
>
>