Re: [PATCH] ARM: dts: bcm283x: Add cells encoding format to firmware bus

[Matthias Brugger]

On 26/03/2020 14:44, Nicolas Saenz Julienne wrote:
> With the introduction of 55c7c0621078 ("ARM: dts: bcm283x: Fix vc4's
> firmware bus DMA limitations") the firmware bus has to comply with
> /soc's DMA limitations. Ultimately linking both buses to a same
> dma-ranges property. The patch (and author) missed the fact that a bus'
> #address-cells and #size-cells properties are not inherited, but set to
> a fixed value which, in this case, doesn't match /soc's. This, although
> not breaking Linux's DMA mapping functionality, generates ugly dtc
> warnings.
> 
> Fix the issue by adding the correct address and size cells properties
> under the firmware bus.
> 
> Fixes: 55c7c0621078 ("ARM: dts: bcm283x: Fix vc4's firmware bus DMA limitations")
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>

Reviewed-by: Matthias Brugger <mbrugger@xxxxxxxx>

> ---
>  arch/arm/boot/dts/bcm2835-rpi.dtsi | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/bcm2835-rpi.dtsi b/arch/arm/boot/dts/bcm2835-rpi.dtsi
> index fd2c766e0f71..f7ae5a4530b8 100644
> --- a/arch/arm/boot/dts/bcm2835-rpi.dtsi
> +++ b/arch/arm/boot/dts/bcm2835-rpi.dtsi
> @@ -14,6 +14,9 @@ act {
>  	soc {
>  		firmware: firmware {
>  			compatible = "raspberrypi,bcm2835-firmware", "simple-bus";
> +			#address-cells = <1>;
> +			#size-cells = <1>;
> +
>  			mboxes = <&mailbox>;
>  			dma-ranges;
>  		};
>