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From:   Damien Le Moal <Damien.LeMoal@wdc.com>
To:     Vaibhav Gupta <vaibhavgupta40@gmail.com>,
        Bjorn Helgaas <helgaas@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Bjorn Helgaas <bjorn@helgaas.com>,
        Vaibhav Gupta <vaibhav.varodek@gmail.com>,
        Jens Axboe <axboe@kernel.dk>,
        Joshua Morris <josh.h.morris@us.ibm.com>,
        Philip Kelleher <pjk1939@linux.ibm.com>
CC:     "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-kernel-mentees@lists.linuxfoundation.org" 
        <linux-kernel-mentees@lists.linuxfoundation.org>,
        Shuah Khan <skhan@linuxfoundation.org>
Subject: Re: [PATCH v2 3/3] skd: use generic power management
Thread-Topic: [PATCH v2 3/3] skd: use generic power management
Thread-Index: AQHWXpopAyN24hyhnE6CLtHPJKt76g==
Date:   Tue, 21 Jul 2020 02:57:28 +0000
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 <20200720133002.448809-1-vaibhavgupta40@gmail.com>
 <20200720133002.448809-4-vaibhavgupta40@gmail.com>
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On 2020/07/20 22:32, Vaibhav Gupta wrote:=0A=
> Drivers using legacy PM have to manage PCI states and device's PM states=
=0A=
> themselves. They also need to take care of configuration registers.=0A=
> =0A=
> With improved and powerful support of generic PM, PCI Core takes care of=
=0A=
> above mentioned, device-independent, jobs.=0A=
> =0A=
> This driver makes use of PCI helper functions like=0A=
> pci_save/restore_state(), pci_enable/disable_device(),=0A=
> pci_request/release_regions(), pci_set_power_state() and=0A=
> pci_set_master() to do required operations. In generic mode, they are no=
=0A=
> longer needed.=0A=
> =0A=
> Change function parameter in both .suspend() and .resume() to=0A=
> "struct device*" type. Use to_pci_dev() to get "struct pci_dev*" variable=
.=0A=
=0A=
This commit message is rather vague, and the last sentence actually does no=
t=0A=
describe correctly the change. What about something very simple, yet clear,=
 like=0A=
this:=0A=
=0A=
skd: use generic power management=0A=
=0A=
Switch from the legacy .suspend()/.resume() power management interface to t=
he=0A=
generic power management interface using the single .driver.pm() method. Th=
is=0A=
avoids the need for the driver to directly call most of the PCI helper func=
tions=0A=
and device power state control functions as the generic power management=0A=
interface takes care of the necessary operations.=0A=
=0A=
> =0A=
> Compile-tested only.=0A=
> =0A=
> Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>=0A=
> ---=0A=
>  drivers/block/skd_main.c | 30 ++++++++----------------------=0A=
>  1 file changed, 8 insertions(+), 22 deletions(-)=0A=
> =0A=
> diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c=0A=
> index 51569c199a6c..7f2d42900b38 100644=0A=
> --- a/drivers/block/skd_main.c=0A=
> +++ b/drivers/block/skd_main.c=0A=
> @@ -3315,10 +3315,11 @@ static void skd_pci_remove(struct pci_dev *pdev)=
=0A=
>  	return;=0A=
>  }=0A=
>  =0A=
> -static int skd_pci_suspend(struct pci_dev *pdev, pm_message_t state)=0A=
> +static int __maybe_unused skd_pci_suspend(struct device *dev)=0A=
>  {=0A=
>  	int i;=0A=
>  	struct skd_device *skdev;=0A=
> +	struct pci_dev *pdev =3D to_pci_dev(dev);=0A=
>  =0A=
>  	skdev =3D pci_get_drvdata(pdev);=0A=
>  	if (!skdev) {=0A=
> @@ -3337,18 +3338,15 @@ static int skd_pci_suspend(struct pci_dev *pdev, =
pm_message_t state)=0A=
>  	if (skdev->pcie_error_reporting_is_enabled)=0A=
>  		pci_disable_pcie_error_reporting(pdev);=0A=
>  =0A=
> -	pci_release_regions(pdev);=0A=
> -	pci_save_state(pdev);=0A=
> -	pci_disable_device(pdev);=0A=
> -	pci_set_power_state(pdev, pci_choose_state(pdev, state));=0A=
>  	return 0;=0A=
>  }=0A=
>  =0A=
> -static int skd_pci_resume(struct pci_dev *pdev)=0A=
> +static int __maybe_unused skd_pci_resume(struct device *dev)=0A=
>  {=0A=
>  	int i;=0A=
>  	int rc =3D 0;=0A=
>  	struct skd_device *skdev;=0A=
> +	struct pci_dev *pdev =3D to_pci_dev(dev);=0A=
>  =0A=
>  	skdev =3D pci_get_drvdata(pdev);=0A=
>  	if (!skdev) {=0A=
> @@ -3356,16 +3354,8 @@ static int skd_pci_resume(struct pci_dev *pdev)=0A=
>  		return -1;=0A=
>  	}=0A=
>  =0A=
> -	pci_set_power_state(pdev, PCI_D0);=0A=
> -	pci_enable_wake(pdev, PCI_D0, 0);=0A=
> -	pci_restore_state(pdev);=0A=
> +	device_wakeup_disable(dev);=0A=
>  =0A=
> -	rc =3D pci_enable_device(pdev);=0A=
> -	if (rc)=0A=
> -		return rc;=0A=
> -	rc =3D pci_request_regions(pdev, DRV_NAME);=0A=
> -	if (rc)=0A=
> -		goto err_out;=0A=
>  	rc =3D dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));=0A=
>  	if (rc)=0A=
>  		rc =3D dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));=0A=
> @@ -3374,7 +3364,6 @@ static int skd_pci_resume(struct pci_dev *pdev)=0A=
>  		goto err_out_regions;=0A=
>  	}=0A=
>  =0A=
> -	pci_set_master(pdev);=0A=
>  	rc =3D pci_enable_pcie_error_reporting(pdev);=0A=
>  	if (rc) {=0A=
>  		dev_err(&pdev->dev,=0A=
> @@ -3427,10 +3416,6 @@ static int skd_pci_resume(struct pci_dev *pdev)=0A=
>  		pci_disable_pcie_error_reporting(pdev);=0A=
>  =0A=
>  err_out_regions:=0A=
> -	pci_release_regions(pdev);=0A=
> -=0A=
> -err_out:=0A=
> -	pci_disable_device(pdev);=0A=
>  	return rc;=0A=
>  }=0A=
>  =0A=
> @@ -3450,13 +3435,14 @@ static void skd_pci_shutdown(struct pci_dev *pdev=
)=0A=
>  	skd_stop_device(skdev);=0A=
>  }=0A=
>  =0A=
> +static SIMPLE_DEV_PM_OPS(skd_pci_pm_ops, skd_pci_suspend, skd_pci_resume=
);=0A=
> +=0A=
>  static struct pci_driver skd_driver =3D {=0A=
>  	.name		=3D DRV_NAME,=0A=
>  	.id_table	=3D skd_pci_tbl,=0A=
>  	.probe		=3D skd_pci_probe,=0A=
>  	.remove		=3D skd_pci_remove,=0A=
> -	.suspend	=3D skd_pci_suspend,=0A=
> -	.resume		=3D skd_pci_resume,=0A=
> +	.driver.pm	=3D &skd_pci_pm_ops,=0A=
>  	.shutdown	=3D skd_pci_shutdown,=0A=
>  };=0A=
>  =0A=
> =0A=
=0A=
Apart from the commit message, this looks OK to me.=0A=
I will give this a spin today on the hardware to check.=0A=
=0A=
=0A=
-- =0A=
Damien Le Moal=0A=
Western Digital Research=0A=