Re: [PATCH v4 5/6] PCI: dwc: rcar-gen4: Handle PERST via reset subsystem

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

Pre-existing issues:
- [High] Calling pci_epc_init_notify() and returning an error after deinitializing endpoint resources in rcar_gen4_add_dw_pcie_ep().
- [Medium] Missing of_node_put() for msi_node obtained from of_msi_xlate() in rcar_gen4_pcie_host_msi_addr().
--

commit d2f3f23cb3b48c3f0a77ad5561fa549d03ac01cf
Author: Marek Vasut <marek.vasut+renesas@mailbox.org>

PCI: dwc: rcar-gen4: Handle PERST via reset subsystem

This patch supports handling the PERST signal via both GPIO and the reset
subsystem. This change prepares the driver for R-Car Gen5 support, where
PERST might only be accessible via an SCMI reset.

> diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> index c768a9c7b3b76..89472a4becc46 100644
> --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c

[ ... ]

> @@ -494,6 +510,22 @@ static int rcar_gen4_pcie_enable_device(struct pci_host_bridge *bridge,
>  	return 0;
>  }
>  

[Severity: Medium]
This is a pre-existing issue, but does rcar_gen4_pcie_host_msi_addr()
leak the msi_node obtained from of_msi_xlate() on successful return?

drivers/pci/controller/dwc/pcie-rcar-gen4.c:rcar_gen4_pcie_host_msi_addr() {
    ...
	of_msi_xlate(dev, &msi_node, 0);
	if (!msi_node)
		return -ENODEV;
    ...
	*msi_addr = addr;
	return 0;
}

It appears the reference count of msi_node is never decremented on this return
path. Should we call of_node_put(msi_node) before returning?

[ ... ]

> @@ -747,6 +782,7 @@ static void rcar_gen4_pcie_remove(struct platform_device *pdev)
>  
>  	rcar_gen4_remove_dw_pcie(rcar);
>  	rcar_gen4_pcie_unprepare(rcar);
> +	reset_control_put(rcar->perst);
>  }

[Severity: High]
This isn't a bug introduced by this patch, but can rcar_gen4_add_dw_pcie_ep()
trigger an initialization notification on a deinitialized endpoint if
dw_pcie_ep_init_registers() fails?

drivers/pci/controller/dwc/pcie-rcar-gen4.c:rcar_gen4_add_dw_pcie_ep() {
    ...
	ret = dw_pcie_ep_init_registers(ep);
	if (ret) {
		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
		dw_pcie_ep_deinit(ep);
	}

	pci_epc_init_notify(ep->epc);

	return ret;
}

Should there be a return statement inside the error handling block for
dw_pcie_ep_init_registers() to avoid calling pci_epc_init_notify()
on a deinitialized EPC?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260905212649.360498-1-marek.vasut+renesas@mailbox.org?part=5