Re: [PATCH] PCI: cadence: Fixed cdns_pcie_host_link_setup return value.

[Hans Zhang]

On 12/19/24 03:33, Siddharth Vadapalli wrote:
> On Thu, Dec 19, 2024 at 03:14:52AM -0500, Hans Zhang wrote:
> > If the PCIe link never came up, the enumeration process
> > should not be run.
> The link could come up at a later point in time. Please refer to the
> implementation of:
> dw_pcie_host_init() in drivers/pci/controller/dwc/pcie-designware-host.c
> wherein we have the following:
> 	/* Ignore errors, the link may come up later */
> 	dw_pcie_wait_for_link(pci);
>
> It seems to me that the logic behind ignoring the absence of the link
> within cdns_pcie_host_link_setup() instead of erroring out, is similar to
> that of dw_pcie_wait_for_link().
>
> Regards,
> Siddharth.
>
>
> If a PCIe port is not connected to a device. The PCIe link does not
> go up. The current code returns success whether the device is connected
> or not. Cadence IP's ECAM requires an LTSSM at L0 to access the RC's
> config space registers. Otherwise the enumeration process will hang.
>
> Regards,
> Hans