Re: [PATCH] arm64: dts: fsd: Change the reg properties from 64-bit to 32-bit

[Robin Murphy]

On 2022-11-16 11:16, Arnd Bergmann wrote:
> On Wed, Nov 16, 2022, at 10:12, Vivek Yadav wrote:
> > Change the reg properties from 64-bit to 32-bit for all IPs, as none of
> > the nodes are above 32-bit range in the fsd SoC.
> >
> > Since dma-ranges length does not fit into 32-bit size, keep it 64-bit
> > and move it to specific node where it is used instead of SoC section.
>
> I don't think that works, the dma-ranges property is part of the
> bus, not a particular device:
>
>   		mdma0: dma-controller@10100000 {
>   			compatible = "arm,pl330", "arm,primecell";
> -			reg = <0x0 0x10100000 0x0 0x1000>;
> +			reg = <0x10100000 0x1000>;
>   			interrupts = <GIC_SPI 424 IRQ_TYPE_LEVEL_HIGH>;
>   			#dma-cells = <1>;
>   			clocks = <&clock_imem IMEM_DMA0_IPCLKPORT_ACLK>;
>   			clock-names = "apb_pclk";
>   			iommus = <&smmu_imem 0x800 0x0>;
> +			#address-cells = <2>;
> +			#size-cells = <2>;
> +			dma-ranges = <0x0 0x0 0x0 0x10 0x0>;
>   		};
>
> Since the dma-controller has no children, I don't see how this has
> any effect. Also, translating a 36-bit address into a 32-bit
> address just means it gets truncated anyway, so there is no
> point in making it appear to have a larger address range.

Yes, this is definitely bogus on both counts.

Thanks,
Robin.