Re: [PATCH] PCI: iproc: Skip BCMA-attached controllers in the platform bus driver

[Florian Fainelli]

On 10/18/26 23:52, Semih Baskan wrote:
> Since commit 767012397976 ("ARM: dts: BCM5301X: Describe PCIe
> controllers fully"), the Northstar PCIe nodes under the "brcm,bus-axi"
> node have compatible = "brcm,iproc-pcie". bcma_bus_register() creates
> platform devices for the children of that node before it registers its
> own cores, so pcie-iproc-platform probes these controllers before
> pcie-iproc-bcma does, as IPROC_PCIE_PAXB.
>
> IPROC_PCIE_PAXB sets has_apb_err_disable, so the first config read on
> bus 1 reads APB_ERR_EN at offset 0xf40. The report in the Closes: link
> shows that read taking an external abort. On a BCM47081 (PCIe core
> revision 0x01) with a device behind the root port, the board does not
> boot, and it boots when has_apb_err_disable is cleared.
>
> Return -ENODEV for a controller whose parent is "brcm,bus-axi", before
> the driver allocates or maps anything, so that the controller is left
> to pcie-iproc-bcma. The devicetree stays as it is. The check does not
> depend on CONFIG_PCIE_IPROC_BCMA, because a kernel with only
> pcie-iproc-platform does not boot on the BCM47081 either. On a BCM47094
> (core revision 0x07) pcie-iproc-platform enumerates the devices on its
> own, so there a kernel without CONFIG_PCIE_IPROC_BCMA loses PCIe, as
> before v7.1. CONFIG_PCIE_IPROC_BCMA defaults to y on ARCH_BCM_5301X.
>
> Tested on an ASUS RT-N18U (BCM47081) on a 6.18 kernel with the
> controller/iproc-bcma changes backported. With both drivers enabled,
> pcie-iproc-bcma binds controller 0, the BCM4360 behind it enumerates
> and the platform driver logs nothing. With only pcie-iproc-platform
> enabled, the board boots without PCIe. Without this change, neither
> configuration boots on this board.
>
> Fixes: 767012397976 ("ARM: dts: BCM5301X: Describe PCIe controllers fully")
> Reported-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
> Closes: https://lore.kernel.org/r/0dcfb2db-5536-465a-bee1-afe160535748@xxxxxxxxxxxx
> Suggested-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxxxxxxxx>
> Signed-off-by: Semih Baskan <strst.gs@xxxxxxxxx>

On a SmartRG SR400-AC which is based upon BCM4708:

Tested-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>

Thank you Semih!
--
Florian