Re: [PATCH v2 4/4] arm64: dts: broadcom: Add support for BCM2712

Andrea della Porta
2024-05-16T08:36:20Z

On 09:14 Fri 10 May , Florian Fainelli wrote:
> On 5/10/24 07:35, Andrea della Porta wrote:
>
> This should be #size-cells = <2> to be future proof and support over 4GB of
> DRAM, because the DDR controller and the memory map on that chip have been
> designed with that requirement.
>
> > +
> > + interrupt-parent = <&gicv2>;
> > +
> > + axi: axi {
> > + compatible = "simple-bus";
> > + #address-cells = <2>;
> > + #size-cells = <1>;
> > + ranges;
>
> The AXI peripheral window should be defined in the ranges property. The
> aperture is from 0x10_0000_0000 to 0x10_3FFF_FFFF.
>
> From that point on you can define all peripherals under the axi node to be
> relative to that axi aperture, just like what you did for the legacy Pi
> peripherals in the subsequent bus node.

This doesn't seem to match with what I have here:
- some axi peripherals goes beyond 0x10_3FFF_FFFF (e.g. the interrupt
controller is @0x107fff9000)
- downstream dts have that ranges going from 0x10 0x00000000 0x11 0x00000000,
so to span all the peripheral (included e.g. the above int controller)
- another comment in downstream dts says: // 10_00000000-1x_xxxxxxxx = up to
64GB system RAM

I'm a little confused here, of course we could also define multiple ranges
but I don't really know what the boundaries are. Anyway, I would opt for the
extended range (0x10 0x00000000 - 0x11 0x00000000) unless there is concern
about it. Any thoughts?

Many thanks,
Andrea