[PATCH] PCI: dw-rockchip: Enumerate endpoints based on dll_link_up irq in the combined sys irq

[Bjorn Helgaas]

On Wed, Nov 27, 2024 at 03:50:42PM +0100, Niklas Cassel wrote:
> Most boards using the pcie-dw-rockchip PCIe controller lack standard
> hotplug support.
> 
> Thus, when an endpoint is attached to the SoC, users have to rescan the bus
> manually to enumerate the device. This can be avoided by using the
> 'dll_link_up' interrupt in the combined system interrupt 'sys'.
> 
> Once the 'dll_link_up' irq is received, the bus underneath the host bridge
> is scanned to enumerate PCIe endpoint devices.
> 
> This commit implements the same functionality that was implemented in the
> DWC based pcie-qcom driver in commit 4581403f6792 ("PCI: qcom: Enumerate
> endpoints based on Link up event in 'global_irq' interrupt").
> 
> The Root Complex specific device tree binding for pcie-dw-rockchip already
> has the 'sys' interrupt marked as required, so there is no need to update
> the device tree binding. This also means that we can request the 'sys' IRQ
> unconditionally.

Thanks for doing this!

> @@ -436,7 +481,16 @@ static int rockchip_pcie_configure_rc(struct rockchip_pcie *rockchip)
>  	pp = &rockchip->pci.pp;
>  	pp->ops = &rockchip_pcie_host_ops;
>  
> -	return dw_pcie_host_init(pp);
> +	ret = dw_pcie_host_init(pp);
> +	if (ret) {
> +		dev_err(dev, "failed to initialize host\n");
> +		return ret;
> +	}
> +
> +	/* unmask DLL up/down indicator */
> +	rockchip_pcie_writel_apb(rockchip, 0x20000, PCIE_CLIENT_INTR_MASK_MISC);

I know we already had a bare 0x60000 in rockchip_pcie_configure_ep(),
but can we add #defines for both of these PCIE_CLIENT_INTR_MASK_MISC
bits?