On Mon, Aug 30, 2021 at 12:39:09PM +0200, Nicolas Saenz Julienne wrote:
> dtbs_check currently complains that:
>
> arch/arm/boot/dts/bcm2711-rpi-4-b.dts:220.10-231.4: Warning
> (pci_device_reg): /scb/pcie@7d500000/pci@1,0: PCI unit address format
> error, expected "0,0"
>
> Unsurprisingly pci@0,0 is the right address, as illustrated by its reg
> property:
>
> &pcie0 {
> pci@0,0 {
> /*
> * As defined in the IEEE Std 1275-1994 document,
> * reg is a five-cell address encoded as (phys.hi
> * phys.mid phys.lo size.hi size.lo). phys.hi
> * should contain the device's BDF as 0b00000000
> * bbbbbbbb dddddfff 00000000. The other cells
> * should be zero.
> */
> reg = <0 0 0 0 0>;
> };
> };
>
> The bus is clearly 0. So fix it.
s/bus/device/
The unit-address format is '<device>,<function>' (and function is
optional). The bus number is not part of the unit-address because that
is dynamic and then the path would not be fixed/known. The bus is part
of 'reg' for true OpenFirmware, but for FDT I think it should always be
0 as the DT is static.
Looks like the child node is wrong (both unit-address and reg) as well:
usb@1,0 {
reg = <0x10000 0 0 0 0>;
resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
};
It doesn't warn because the bridge node is also missing 'device_type =
"pci";'.
This is all fairly hard to get right (see recent hikey970 patches for a
complex example). I'm thinking about writing a tool that generates a DT
with PCI nodes by reading the PCI hierachy from sysfs.
Rob
