Re: [PATCH v2] PCI: starfive: Enable PCIe controller's runtime PM before probing host bridge

[Manivannan Sadhasivam]

On Fri, Oct 11, 2024 at 04:55:30PM -0700, Mayank Rana wrote:
> PCIe controller device (i.e. PCIe starfive device) is parent to PCIe host
> bridge device. To enable runtime PM of PCIe host bridge device (child
> device), it is must to enable parent device's runtime PM to avoid seeing
> WARN_ON as "Enabling runtime PM for inactive device with active children".

"to avoid seeing the below warning from PM core:

pcie-starfive 940000000.pcie: Enabling runtime PM for inactive device
with active children"

> Fix this issue by enabling starfive pcie controller device's runtime PM
> before calling into pci_host_probe() through plda_pcie_host_init().

"before calling pci_host_probe() in plda_pcie_host_init()"

> 
> Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> Signed-off-by: Mayank Rana <quic_mrana@xxxxxxxxxxx>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>

- Mani

> ---
> v1->v2: Updated commit description based on Bjorn's feedback
> Link to v1: https://patchwork.kernel.org/project/linux-pci/patch/20241010202950.3263899-1-quic_mrana@xxxxxxxxxxx/
>  
>  drivers/pci/controller/plda/pcie-starfive.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/plda/pcie-starfive.c b/drivers/pci/controller/plda/pcie-starfive.c
> index 0567ec373a3e..e73c1b7bc8ef 100644
> --- a/drivers/pci/controller/plda/pcie-starfive.c
> +++ b/drivers/pci/controller/plda/pcie-starfive.c
> @@ -404,6 +404,9 @@ static int starfive_pcie_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
> +
>  	plda->host_ops = &sf_host_ops;
>  	plda->num_events = PLDA_MAX_EVENT_NUM;
>  	/* mask doorbell event */
> @@ -413,11 +416,12 @@ static int starfive_pcie_probe(struct platform_device *pdev)
>  	plda->events_bitmap <<= PLDA_NUM_DMA_EVENTS;
>  	ret = plda_pcie_host_init(&pcie->plda, &starfive_pcie_ops,
>  				  &stf_pcie_event);
> -	if (ret)
> +	if (ret) {
> +		pm_runtime_put_sync(&pdev->dev);
> +		pm_runtime_disable(&pdev->dev);
>  		return ret;
> +	}
>  
> -	pm_runtime_enable(&pdev->dev);
> -	pm_runtime_get_sync(&pdev->dev);
>  	platform_set_drvdata(pdev, pcie);
>  
>  	return 0;
> -- 
> 2.25.1
> 

-- 
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