On Mon, Aug 30, 2021 at 11:45 AM <nsaenzju@xxxxxxxxxx> wrote:
>
> 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>;
> };
> };
> };
Yes, that looks correct.
Rob
