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

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

On Thu, Jul 30, 2020 at 04:39:30PM +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/smartpqi/smartpqi_init.c | 44 +++++++++++++++++++--------
>  1 file changed, 31 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
> index cd157f11eb22..7061bd26897a 100644
> --- a/drivers/scsi/smartpqi/smartpqi_init.c
> +++ b/drivers/scsi/smartpqi/smartpqi_init.c
> @@ -8059,11 +8059,11 @@ static void pqi_process_module_params(void)
>  	pqi_process_lockup_action_param();
>  }
>  
> -static __maybe_unused int pqi_suspend(struct pci_dev *pci_dev, pm_message_t state)
> +static int pqi_suspend_late(struct device *dev, pm_message_t state)
>  {
>  	struct pqi_ctrl_info *ctrl_info;
>  
> -	ctrl_info = pci_get_drvdata(pci_dev);
> +	ctrl_info = dev_get_drvdata(dev);
>  
>  	pqi_disable_events(ctrl_info);
>  	pqi_cancel_update_time_worker(ctrl_info);
> @@ -8081,20 +8081,33 @@ static __maybe_unused int pqi_suspend(struct pci_dev *pci_dev, pm_message_t stat
>  	if (state.event == PM_EVENT_FREEZE)
>  		return 0;
>  
> -	pci_save_state(pci_dev);
> -	pci_set_power_state(pci_dev, pci_choose_state(pci_dev, state));
> -
>  	ctrl_info->controller_online = false;
>  	ctrl_info->pqi_mode_enabled = false;
>  
>  	return 0;
>  }
>  
> -static __maybe_unused int pqi_resume(struct pci_dev *pci_dev)
> +static __maybe_unused int pqi_suspend(struct device *dev)
> +{
> +	return pqi_suspend_late(dev, PMSG_SUSPEND);
> +}
> +
> +static __maybe_unused int pqi_hibernate(struct device *dev)
> +{
> +	return pqi_suspend_late(dev, PMSG_HIBERNATE);
> +}
> +
> +static __maybe_unused int pqi_freeze(struct device *dev)
> +{
> +	return pqi_suspend_late(dev, PMSG_FREEZE);
> +}
> +
> +static __maybe_unused int pqi_resume(struct device *dev)
>  {
>  	int rc;
>  	struct pqi_ctrl_info *ctrl_info;
>  
> +	struct pci_dev *pci_dev = to_pci_dev(dev);
>  	ctrl_info = pci_get_drvdata(pci_dev);
>  
>  	if (pci_dev->current_state != PCI_D0) {
> @@ -8115,9 +8128,6 @@ static __maybe_unused int pqi_resume(struct pci_dev *pci_dev)
>  		return 0;
>  	}
>  
> -	pci_set_power_state(pci_dev, PCI_D0);
> -	pci_restore_state(pci_dev);
> -
>  	return pqi_ctrl_init_resume(ctrl_info);
>  }
>  
> @@ -8480,16 +8490,24 @@ static const struct pci_device_id pqi_pci_id_table[] = {
>  
>  MODULE_DEVICE_TABLE(pci, pqi_pci_id_table);
>  
> +static const struct dev_pm_ops pqi_pm_ops = {
> +#ifdef CONFIG_PM_SLEEP
> +	.suspend = pqi_suspend,
> +	.resume = pqi_resume,
> +	.freeze = pqi_freeze,
> +	.thaw = pqi_resume,
> +	.poweroff = pqi_hibernate,
> +	.restore = pqi_resume,
> +#endif
> +};
> +
>  static struct pci_driver pqi_pci_driver = {
>  	.name = DRIVER_NAME_SHORT,
>  	.id_table = pqi_pci_id_table,
>  	.probe = pqi_pci_probe,
>  	.remove = pqi_pci_remove,
>  	.shutdown = pqi_shutdown,
> -#if defined(CONFIG_PM)
> -	.suspend = pqi_suspend,
> -	.resume = pqi_resume,
> -#endif
> +	.driver.pm = &pqi_pm_ops
>  };
>  
>  static int __init pqi_init(void)
> -- 
> 2.27.0
> 
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