Maybe the problem is that some root bus numbers are hardwired to fixed
non-zero values? I thought we already handled that, but perhaps not.
What does the user see without this patch? Some warning? Failure to
enumerate some devices? Include a hint here if possible so users can
find the fix to their issue.
> Suggested-by: Nirmal Patel <nirmal.patel@xxxxxxxxxxxxxxx>
> Reviewed-by: Mariusz Tkaczyk <mariusz.tkaczyk@xxxxxxxxxxxxxxx>
> Signed-off-by: Szymon Durawa <szymon.durawa@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/controller/vmd.c | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index 842b70a21325..bb47e0a76c89 100755
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -404,8 +404,22 @@ static inline u8 vmd_has_pch_rootbus(struct vmd_dev *vmd)
> static void __iomem *vmd_cfg_addr(struct vmd_dev *vmd, struct pci_bus *bus,
> unsigned int devfn, int reg, int len)
> {
> - unsigned int busnr_ecam = bus->number - vmd->busn_start[VMD_BUS_0];
> - u32 offset = PCIE_ECAM_OFFSET(busnr_ecam, devfn, reg);
> + unsigned char bus_number;
> + unsigned int busnr_ecam;
> + u32 offset;
> +
> + /*
> + * VMD WA: for PCH rootbus, bus number is set to VMD_PRIMARY_PCH_BUS
> + * (see comment in vmd_create_pch_bus()) but original value is 0xE1
> + * which is stored in vmd->busn_start[VMD_BUS_1].
Used 225 elsewhere. Would be nice to at least use the same base (dec
vs hex), and preferably the same #define.
> + */
> + if (vmd_has_pch_rootbus(vmd) && bus->number == VMD_PRIMARY_PCH_BUS)
> + bus_number = vmd->busn_start[VMD_BUS_1];
> + else
> + bus_number = bus->number;
> +
> + busnr_ecam = bus_number - vmd->busn_start[VMD_BUS_0];
> + offset = PCIE_ECAM_OFFSET(busnr_ecam, devfn, reg);
>
> if (offset + len >= resource_size(&vmd->dev->resource[VMD_CFGBAR]))
> return NULL;
> @@ -1023,6 +1037,14 @@ static int vmd_create_pch_bus(struct vmd_dev *vmd, struct pci_sysdata *sd,
> */
> vmd->bus[VMD_BUS_1]->primary = VMD_PRIMARY_PCH_BUS;
>
> + /* This is a workaround for pci_scan_bridge_extend() code.
Use the prevailing comment style:
/*
* This is ...
> + * It assigns setup as broken when primary != bus->number and
> + * for PCH rootbus primary is not "hard-wired to 0".
> + * To avoid this, vmd->bus[VMD_BUS_1]->number and
> + * vmd->bus[VMD_BUS_1]->primary are updated to the same value.
> + */
> + vmd->bus[VMD_BUS_1]->number = VMD_PRIMARY_PCH_BUS;
> +
> vmd_copy_host_bridge_flags(
> pci_find_host_bridge(vmd->dev->bus),
> to_pci_host_bridge(vmd->bus[VMD_BUS_1]->bridge));
> --
> 2.39.3
>
