Re: [PATCH v4 06/10] mhi: pci_generic: Add suspend/resume/recovery procedure

[Hemant Kumar <hemantk@codeaurora.org>]

Hi Loic,

On 12/10/20 2:02 AM, Loic Poulain wrote:
> Add support for system wide suspend/resume. During suspend, MHI
> device controller must be put in M3 state and PCI bus in D3 state.
> 
> Add a recovery procedure allowing to reinitialize the device in case
> of error during resume steps, which can happen if device loses power
> (and so its context) while system suspend.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>[..]
> +int  __maybe_unused mhi_pci_suspend(struct device *dev)
suspend API is not static but resume is. Any reason for that ?
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);
> +	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
> +
> +	cancel_work_sync(&mhi_pdev->recovery_work);
> +
> +	/* Transition to M3 state */
> +	mhi_pm_suspend(mhi_cntrl);
> +
> +	pci_save_state(pdev);
> +	pci_disable_device(pdev);
> +	pci_wake_from_d3(pdev, true);
> +	pci_set_power_state(pdev, PCI_D3hot);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused mhi_pci_resume(struct device *dev)
> +{
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);
> +	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
> +	int err;
> +
> +	pci_set_power_state(pdev, PCI_D0);
> +	pci_restore_state(pdev);
> +	pci_set_master(pdev);
> +
> +	err = pci_enable_device(pdev);
> +	if (err)
> +		goto err_recovery;
> +
> +	/* Exit M3, transition to M0 state */
> +	err = mhi_pm_resume(mhi_cntrl);
> +	if (err) {
> +		dev_err(&pdev->dev, "failed to resume device: %d\n", err);
> +		goto err_recovery;
> +	}
> +
> +	return 0;
> +
> +err_recovery:
> +	/* The device may have loose power or crashed, try recovering it */
> +	queue_work(system_long_wq, &mhi_pdev->recovery_work);
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops mhi_pci_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(mhi_pci_suspend, mhi_pci_resume)
> +};
> +
>   static struct pci_driver mhi_pci_driver = {
>   	.name		= "mhi-pci-generic",
>   	.id_table	= mhi_pci_id_table,
>   	.probe		= mhi_pci_probe,
>   	.remove		= mhi_pci_remove,
>   	.err_handler	= &mhi_pci_err_handler,
> +	.driver.pm	= &mhi_pci_pm_ops
>   };
>   module_pci_driver(mhi_pci_driver);
>   
> 

Overall change looks good from my side. Once you address or answer my 
query you can add my

Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>

Thanks,
Hemant
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