Re: [Linux-kernel-mentees] [PATCH v2 15/15] scsi: pmcraid: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

On Mon, Jul 20, 2020 at 07:04:28PM +0530, 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_set_power_state() and 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.
> 
> In function pmcraid_resume(), earlier, the variable "rc" was set by
> pci_enable_device() which is now removed. Since PCI core does the required
> job, initialize "rc" with 0 value when declaring it.
> 
> Compile-tested only.
> 
> Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
> ---
>  drivers/scsi/pmcraid.c | 44 +++++++++++-------------------------------
>  1 file changed, 11 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
> index aa9ae2ae8579..b6b70ac2e2ee 100644
> --- a/drivers/scsi/pmcraid.c
> +++ b/drivers/scsi/pmcraid.c
> @@ -5237,54 +5237,39 @@ static void pmcraid_remove(struct pci_dev *pdev)
>  	return;
>  }
>  
> -#ifdef CONFIG_PM
>  /**
>   * pmcraid_suspend - driver suspend entry point for power management
> - * @pdev:   PCI device structure
> - * @state:  PCI power state to suspend routine
> + * @dev:   Device structure
>   *
>   * Return Value - 0 always
>   */
> -static int pmcraid_suspend(struct pci_dev *pdev, pm_message_t state)
> +static int __maybe_unused pmcraid_suspend(struct device *dev)
>  {
> +	struct pci_dev *pdev = to_pci_dev(dev);
>  	struct pmcraid_instance *pinstance = pci_get_drvdata(pdev);
>  
>  	pmcraid_shutdown(pdev);
>  	pmcraid_disable_interrupts(pinstance, ~0);
>  	pmcraid_kill_tasklets(pinstance);
> -	pci_set_drvdata(pinstance->pdev, pinstance);
>  	pmcraid_unregister_interrupt_handler(pinstance);
> -	pci_save_state(pdev);
> -	pci_disable_device(pdev);
> -	pci_set_power_state(pdev, pci_choose_state(pdev, state));
>  
>  	return 0;
>  }
>  
>  /**
>   * pmcraid_resume - driver resume entry point PCI power management
> - * @pdev: PCI device structure
> + * @dev: Device structure
>   *
>   * Return Value - 0 in case of success. Error code in case of any failure
>   */
> -static int pmcraid_resume(struct pci_dev *pdev)
> +static int __maybe_unused pmcraid_resume(struct device *dev)
>  {
> +	struct pci_dev *pdev = to_pci_dev(dev);
>  	struct pmcraid_instance *pinstance = pci_get_drvdata(pdev);
>  	struct Scsi_Host *host = pinstance->host;
> -	int rc;
> -
> -	pci_set_power_state(pdev, PCI_D0);
> -	pci_enable_wake(pdev, PCI_D0, 0);
> -	pci_restore_state(pdev);
> -
> -	rc = pci_enable_device(pdev);
> -
> -	if (rc) {
> -		dev_err(&pdev->dev, "resume: Enable device failed\n");
> -		return rc;
> -	}
> +	int rc = 0;
>  
> -	pci_set_master(pdev);
> +	device_wakeup_disable(dev);
>  
>  	if (sizeof(dma_addr_t) == 4 ||
>  	    dma_set_mask(&pdev->dev, DMA_BIT_MASK(64)))
> @@ -5337,18 +5322,10 @@ static int pmcraid_resume(struct pci_dev *pdev)
>  	scsi_host_put(host);
>  
>  disable_device:
> -	pci_disable_device(pdev);
>  
>  	return rc;
>  }
>  
> -#else
> -
> -#define pmcraid_suspend NULL
> -#define pmcraid_resume  NULL
> -
> -#endif /* CONFIG_PM */
> -
>  /**
>   * pmcraid_complete_ioa_reset - Called by either timer or tasklet during
>   *				completion of the ioa reset
> @@ -5836,6 +5813,8 @@ static int pmcraid_probe(struct pci_dev *pdev,
>  	return -ENODEV;
>  }
>  
> +static SIMPLE_DEV_PM_OPS(pmcraid_pm_ops, pmcraid_suspend, pmcraid_resume);
> +
>  /*
>   * PCI driver structure of pmcraid driver
>   */
> @@ -5844,8 +5823,7 @@ static struct pci_driver pmcraid_driver = {
>  	.id_table = pmcraid_pci_table,
>  	.probe = pmcraid_probe,
>  	.remove = pmcraid_remove,
> -	.suspend = pmcraid_suspend,
> -	.resume = pmcraid_resume,
> +	.driver.pm = &pmcraid_pm_ops,
>  	.shutdown = pmcraid_shutdown
>  };
>  
> -- 
> 2.27.0
> 
.
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