On Mon, 2021-08-30 at 08:39 -0500, Rob Herring wrote:
> 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.
Just to double-check I understood everything, with:
lspci -D -PP
0000:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2711 PCIe Bridge (rev 10)
0000:00:00.0/01:00.0 USB controller: VIA Technologies, Inc. VL805/806 xHCI USB 3.0 Controller (rev 01)
It should look like this:
&pcie0 {
pci@0,0 {
device_type = "pci";
#address-cells = <3>;
#size-cells = <2>;
ranges;
reg = <0 0 0 0 0>;
usb@0,0 {
reg = <0 0 0 0 0>;
resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>;
};
};
};
Thanks!
--
Nicolás Sáenz
