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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 5/16/24 01:36, Andrea della Porta wrote:
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)

The interrupt controller (GIC) is technically its own dedicated bus to the CPU, that's why it is typically added to the root node.

- 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

Yes, up to 64GB of DRAM is correct.


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?

A single range is fine with me, those sort of details should not matter.


Many thanks,
Andrea

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

--
Florian

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature


[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux