Re: [PATCH v6 09/13] PCI: tegra194: Allow system suspend when the Endpoint link is not up

[Vidya Sagar <vidyas@nvidia.com>]

On 24/02/26 00:11, Manikanta Maddireddy wrote:
> From: Vidya Sagar <vidyas@nvidia.com>
> 
> Only a Root port initiates the L2 sequence. PCIe link is kept in L2 state
> during suspend. If Endpoint mode is enabled and the link is up, the
> software cannot proceed with suspend. However, when the PCIe Endpoint
> driver is probed, but the PCIe link is not up, Tegra can go into suspend
> state. So, allow system to suspend in this case.
> 
> Fixes: de2bbf2b71bb ("PCI: tegra194: Don't allow suspend when Tegra PCIe is in EP mode")
> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
> ---
> Changes V1 -> V6: None
> 
>  drivers/pci/controller/dwc/pcie-tegra194.c | 31 +++++++++++++++++-----
>  1 file changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index 61cbb4f230e1..58069b1615b8 100644
> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -2266,16 +2266,28 @@ static void tegra_pcie_dw_remove(struct platform_device *pdev)
>  		gpiod_set_value(pcie->pex_refclk_sel_gpiod, 0);
>  }
>  
> -static int tegra_pcie_dw_suspend_late(struct device *dev)
> +static int tegra_pcie_dw_suspend(struct device *dev)
>  {
>  	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> -	u32 val;
>  
>  	if (pcie->of_data->mode == DW_PCIE_EP_TYPE) {
> -		dev_err(dev, "Failed to Suspend as Tegra PCIe is in EP mode\n");
> -		return -EPERM;
> +		if (pcie->ep_state == EP_STATE_ENABLED) {
> +			dev_err(dev, "Tegra PCIe is in EP mode, suspend not allowed\n");
> +			return -EPERM;
> +		}
> +
> +		disable_irq(pcie->pex_rst_irq);
> +		return 0;
>  	}
>  
> +	return 0;
> +}
> +
> +static int tegra_pcie_dw_suspend_late(struct device *dev)
> +{
> +	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +	u32 val;
> +
>  	if (!pcie->link_state)
>  		return 0;
>  
> @@ -2295,6 +2307,9 @@ static int tegra_pcie_dw_suspend_noirq(struct device *dev)
>  {
>  	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>  
> +	if (pcie->of_data->mode == DW_PCIE_EP_TYPE)
> +		return 0;
> +
>  	if (!pcie->link_state)
>  		return 0;
>  
> @@ -2309,6 +2324,9 @@ static int tegra_pcie_dw_resume_noirq(struct device *dev)
>  	struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
>  	int ret;
>  
> +	if (pcie->of_data->mode == DW_PCIE_EP_TYPE)
> +		return 0;
> +
>  	if (!pcie->link_state)
>  		return 0;
>  
> @@ -2341,8 +2359,8 @@ static int tegra_pcie_dw_resume_early(struct device *dev)
>  	u32 val;
>  
>  	if (pcie->of_data->mode == DW_PCIE_EP_TYPE) {
> -		dev_err(dev, "Suspend is not supported in EP mode");
> -		return -ENOTSUPP;
> +		enable_irq(pcie->pex_rst_irq);
> +		return 0;
>  	}
>  
>  	if (!pcie->link_state)
> @@ -2447,6 +2465,7 @@ static const struct of_device_id tegra_pcie_dw_of_match[] = {
>  };
>  
>  static const struct dev_pm_ops tegra_pcie_dw_pm_ops = {
> +	.suspend = tegra_pcie_dw_suspend,
>  	.suspend_late = tegra_pcie_dw_suspend_late,
>  	.suspend_noirq = tegra_pcie_dw_suspend_noirq,
>  	.resume_noirq = tegra_pcie_dw_resume_noirq,

Reviewed-by: Vidya Sagar <vidyas@nvidia.com>