Re: [Linux-kernel-mentees] [PATCH v2] scsi: stex: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

On Thu, Jul 30, 2020 at 03:46:58PM +0530, Vaibhav Gupta wrote:
> Drivers using legacy power management .suspen()/.resume() callbacks
> have to manage PCI states and device's PM states themselves. They also
> need to take care of standard configuration registers.
> 
> Switch to generic power management framework using a single
> "struct dev_pm_ops" variable to take the unnecessary load from the driver.
> This also avoids the need for the driver to directly call most of the PCI
> helper functions and device power state control functions, as through
> the generic framework PCI Core takes care of the necessary operations,
> and drivers are required to do only device-specific jobs.
> 
> Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
> ---
>  drivers/scsi/stex.c | 37 +++++++++++++++++++++++++++++++------
>  1 file changed, 31 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
> index d4f10c0d813c..5ef6f3cbac11 100644
> --- a/drivers/scsi/stex.c
> +++ b/drivers/scsi/stex.c
> @@ -1972,9 +1972,9 @@ static int stex_choice_sleep_mic(struct st_hba *hba, pm_message_t state)
>  	}
>  }
>  
> -static int stex_suspend(struct pci_dev *pdev, pm_message_t state)
> +static int stex_suspend_late(struct device *dev, pm_message_t state)
>  {
> -	struct st_hba *hba = pci_get_drvdata(pdev);
> +	struct st_hba *hba = dev_get_drvdata(dev);
>  
>  	if ((hba->cardtype == st_yel || hba->cardtype == st_P3)
>  		&& hba->supports_pm == 1)
> @@ -1984,9 +1984,24 @@ static int stex_suspend(struct pci_dev *pdev, pm_message_t state)
>  	return 0;
>  }
>  
> -static int stex_resume(struct pci_dev *pdev)
> +static int __maybe_unused stex_suspend(struct device *dev)
>  {
> -	struct st_hba *hba = pci_get_drvdata(pdev);
> +	return stex_suspend_late(dev, PMSG_SUSPEND);
> +}
> +
> +static int __maybe_unused stex_hibernate(struct device *dev)
> +{
> +	return stex_suspend_late(dev, PMSG_HIBERNATE);
> +}
> +
> +static int __maybe_unused stex_freeze(struct device *dev)
> +{
> +	return stex_suspend_late(dev, PMSG_FREEZE);
> +}
> +
> +static int __maybe_unused stex_resume(struct device *dev)
> +{
> +	struct st_hba *hba = dev_get_drvdata(dev);
>  
>  	hba->mu_status = MU_STATE_STARTING;
>  	stex_handshake(hba);
> @@ -2000,14 +2015,24 @@ static int stex_halt(struct notifier_block *nb, unsigned long event, void *buf)
>  }
>  MODULE_DEVICE_TABLE(pci, stex_pci_tbl);
>  
> +static const struct dev_pm_ops stex_pm_ops = {
> +#ifdef CONFIG_PM_SLEEP
> +	.suspend	= stex_suspend,
> +	.resume		= stex_resume,
> +	.freeze		= stex_freeze,
> +	.thaw		= stex_resume,
> +	.poweroff	= stex_hibernate,
> +	.restore	= stex_resume,
> +#endif
> +};
> +
>  static struct pci_driver stex_pci_driver = {
>  	.name		= DRV_NAME,
>  	.id_table	= stex_pci_tbl,
>  	.probe		= stex_probe,
>  	.remove		= stex_remove,
>  	.shutdown	= stex_shutdown,
> -	.suspend	= stex_suspend,
> -	.resume		= stex_resume,
> +	.driver.pm	= &stex_pm_ops,
>  };
>  
>  static int __init stex_init(void)
> -- 
> 2.27.0
> 
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