Re: [PATCH v2 8/8] PCI: rzg3s-host: Add 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:
- [Medium] The added link training delay is redundantly misplaced and silently fails to apply when the Device Tree property is absent.
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commit 54b605149567b07684ca19210d899f1f515af48d
Author: Hans Zhang <18255117159@163.com>

PCI: rzg3s-host: Add 100 ms delay after link training

This commit attempts to enforce a 100 ms delay after link training completes
for speeds above 5.0 GT/s. It adds a call to pcie_wait_after_link_train()
at the end of rzg3s_pcie_host_init().

> diff --git a/drivers/pci/controller/pcie-rzg3s-host.c b/drivers/pci/controller/pcie-rzg3s-host.c
> index d86e7516dcc29..6ab59c5464cfa 100644
> --- a/drivers/pci/controller/pcie-rzg3s-host.c
> +++ b/drivers/pci/controller/pcie-rzg3s-host.c
> @@ -1390,6 +1390,8 @@ static int rzg3s_pcie_host_init(struct rzg3s_pcie_host *host)
>  	val = readl_relaxed(host->axi + RZG3S_PCI_PCSTAT2);
>  	dev_info(host->dev, "PCIe link status [0x%x]\n", val);
>  
> +	pcie_wait_after_link_train(host->max_link_speed);

If the max-link-speed Device Tree property is omitted, host->max_link_speed
is populated with -EINVAL.

When -EINVAL is passed to pcie_wait_after_link_train(), the max_link_speed > 2
check evaluates to false. Will this cause the delay to be skipped entirely,
even if the actual link speed is above 5.0 GT/s?

Additionally, is this added delay redundant?

Looking at rzg3s_pcie_host_setup(), it already unconditionally sleeps for
100ms before returning:

drivers/pci/controller/pcie-rzg3s-host.c:rzg3s_pcie_host_setup() {
...
	ret = rzg3s_pcie_host_init(host);
	if (ret) {
...
	}

	ret = rzg3s_pcie_set_max_link_speed(host);
	if (ret)
		dev_info(dev, "Failed to set max link speed\n");

	msleep(PCIE_RESET_CONFIG_WAIT_MS);

	return 0;
}

Since rzg3s_pcie_set_max_link_speed() can trigger link retraining, should
the wait occur after that final link training completes rather than here
in rzg3s_pcie_host_init()?

> +
>  	return 0;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260506152346.166056-1-18255117159@163.com?part=8