Re: [Linux-kernel-mentees] [PATCH v2 3/3] skd: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

On Tue, Jul 21, 2020 at 02:57:28AM +0000, Damien Le Moal wrote:
> On 2020/07/20 22:32, Vaibhav Gupta wrote:
> > Drivers using legacy PM have to manage PCI states and device's PM states
> > themselves. They also need to take care of configuration registers.
> > 
> > With improved and powerful support of generic PM, PCI Core takes care of
> > above mentioned, device-independent, jobs.
> > 
> > This driver makes use of PCI helper functions like
> > pci_save/restore_state(), pci_enable/disable_device(),
> > pci_request/release_regions(), pci_set_power_state() and
> > pci_set_master() to do required operations. In generic mode, they are no
> > longer needed.
> > 
> > Change function parameter in both .suspend() and .resume() to
> > "struct device*" type. Use to_pci_dev() to get "struct pci_dev*" variable.
> 
> This commit message is rather vague, and the last sentence actually does not
> describe correctly the change. What about something very simple, yet clear, like
> this:
> 
> skd: use generic power management
> 
> Switch from the legacy .suspend()/.resume() power management interface to the
> generic power management interface using the single .driver.pm() method. This
> avoids the need for the driver to directly call most of the PCI helper functions
> and device power state control functions as the generic power management
> interface takes care of the necessary operations.
>
Okay. I will improve on it. Just inform me after testing that if any other
changes are required. I guess [PATCH 1/3] and [PATCH 2/3] are okay, so I will
only send v3 of [PATCH 3/3] after suggested changes.
> > 
> > Compile-tested only.
> > 
> > Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
> > ---
> >  drivers/block/skd_main.c | 30 ++++++++----------------------
> >  1 file changed, 8 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c
> > index 51569c199a6c..7f2d42900b38 100644
> > --- a/drivers/block/skd_main.c
> > +++ b/drivers/block/skd_main.c
> > @@ -3315,10 +3315,11 @@ static void skd_pci_remove(struct pci_dev *pdev)
> >  	return;
> >  }
> >  
> > -static int skd_pci_suspend(struct pci_dev *pdev, pm_message_t state)
> > +static int __maybe_unused skd_pci_suspend(struct device *dev)
> >  {
> >  	int i;
> >  	struct skd_device *skdev;
> > +	struct pci_dev *pdev = to_pci_dev(dev);
> >  
> >  	skdev = pci_get_drvdata(pdev);
> >  	if (!skdev) {
> > @@ -3337,18 +3338,15 @@ static int skd_pci_suspend(struct pci_dev *pdev, pm_message_t state)
> >  	if (skdev->pcie_error_reporting_is_enabled)
> >  		pci_disable_pcie_error_reporting(pdev);
> >  
> > -	pci_release_regions(pdev);
> > -	pci_save_state(pdev);
> > -	pci_disable_device(pdev);
> > -	pci_set_power_state(pdev, pci_choose_state(pdev, state));
> >  	return 0;
> >  }
> >  
> > -static int skd_pci_resume(struct pci_dev *pdev)
> > +static int __maybe_unused skd_pci_resume(struct device *dev)
> >  {
> >  	int i;
> >  	int rc = 0;
> >  	struct skd_device *skdev;
> > +	struct pci_dev *pdev = to_pci_dev(dev);
> >  
> >  	skdev = pci_get_drvdata(pdev);
> >  	if (!skdev) {
> > @@ -3356,16 +3354,8 @@ static int skd_pci_resume(struct pci_dev *pdev)
> >  		return -1;
> >  	}
> >  
> > -	pci_set_power_state(pdev, PCI_D0);
> > -	pci_enable_wake(pdev, PCI_D0, 0);
> > -	pci_restore_state(pdev);
> > +	device_wakeup_disable(dev);
> >  
> > -	rc = pci_enable_device(pdev);
> > -	if (rc)
> > -		return rc;
> > -	rc = pci_request_regions(pdev, DRV_NAME);
> > -	if (rc)
> > -		goto err_out;
> >  	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
> >  	if (rc)
> >  		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> > @@ -3374,7 +3364,6 @@ static int skd_pci_resume(struct pci_dev *pdev)
> >  		goto err_out_regions;
> >  	}
> >  
> > -	pci_set_master(pdev);
> >  	rc = pci_enable_pcie_error_reporting(pdev);
> >  	if (rc) {
> >  		dev_err(&pdev->dev,
> > @@ -3427,10 +3416,6 @@ static int skd_pci_resume(struct pci_dev *pdev)
> >  		pci_disable_pcie_error_reporting(pdev);
> >  
> >  err_out_regions:
> > -	pci_release_regions(pdev);
> > -
> > -err_out:
> > -	pci_disable_device(pdev);
> >  	return rc;
> >  }
> >  
> > @@ -3450,13 +3435,14 @@ static void skd_pci_shutdown(struct pci_dev *pdev)
> >  	skd_stop_device(skdev);
> >  }
> >  
> > +static SIMPLE_DEV_PM_OPS(skd_pci_pm_ops, skd_pci_suspend, skd_pci_resume);
> > +
> >  static struct pci_driver skd_driver = {
> >  	.name		= DRV_NAME,
> >  	.id_table	= skd_pci_tbl,
> >  	.probe		= skd_pci_probe,
> >  	.remove		= skd_pci_remove,
> > -	.suspend	= skd_pci_suspend,
> > -	.resume		= skd_pci_resume,
> > +	.driver.pm	= &skd_pci_pm_ops,
> >  	.shutdown	= skd_pci_shutdown,
> >  };
> >  
> > 
> 
> Apart from the commit message, this looks OK to me.
> I will give this a spin today on the hardware to check.
> 
Thanks!
--Vaibhav Gupta
> 
> -- 
> Damien Le Moal
> Western Digital Research
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