Re: [PATCH v2 2/8] PCI: cadence: LGA: Add max_link_speed field and 100 ms delay after link training

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The generic PCIe compliance fix is silently bypassed for several Cadence host controllers due to uninitialized `max_link_speed`.
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commit c86b1055b143ccb331408ed591540753d03613ac
Author: Hans Zhang <18255117159@163.com>

PCI: cadence: LGA: Add max_link_speed field and 100 ms delay after link training

This commit adds a mandatory 100 ms delay after link training completes for
speeds > 5.0 GT/s in the Cadence PCIe host controller to comply with PCIe
r6.0. It adds a max_link_speed field to track the speed and triggers the
delay if this speed is greater than 2.

> diff --git a/drivers/pci/controller/cadence/pcie-cadence-host-common.c b/drivers/pci/controller/cadence/pcie-cadence-host-common.c
> index 2b0211870f02a..51376f69d0076 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence-host-common.c
> +++ b/drivers/pci/controller/cadence/pcie-cadence-host-common.c
[ ... ]
> @@ -115,6 +116,9 @@ int cdns_pcie_host_start_link(struct cdns_pcie_rc *rc,
>  	if (!ret && rc->quirk_retrain_flag)
>  		ret = cdns_pcie_retrain(pcie, pcie_link_up);
>  
> +	if (!ret)
> +		pcie_wait_after_link_train(pcie->max_link_speed);

Since struct cdns_pcie is zero-initialized by glue drivers, max_link_speed
will default to 0 for drivers that are not updated by this series (such as
pcie-sg2042.c, pci-sky1.c, and pcie-cadence-plat.c).

If max_link_speed is 0, the condition max_link_speed > 2 in
pcie_wait_after_link_train() will evaluate to false, meaning the mandatory
100ms compliance delay will be bypassed for those platforms.

Could the core driver dynamically read the hardware capability (for example,
from cdns_pcie_readl(pcie, ... + PCI_EXP_LNKCAP) & PCI_EXP_LNKCAP_SLS) when
max_link_speed is 0 to ensure compliance across all Cadence host platforms?

> +
>  	return ret;
>  }
>  EXPORT_SYMBOL_GPL(cdns_pcie_host_start_link);

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Sashiko AI review · https://sashiko.dev/#/patchset/20260506152346.166056-1-18255117159@163.com?part=2