Re: [PATCH 1/2] arm64: dts: qcom: msm8953: Set initial address for memory

[Stephan Gerhold <stephan@gerhold.net>]

On Sun, Oct 15, 2023 at 10:26:01PM +0200, Luca Weiss wrote:
> The dtbs_check really doesn't like having memory without reg set.
> Address this by setting it to 0x10000000 which seems to be the value
> filled in by the bootloader.
> 

Looks like MSM8953 has the same RAM setup as MSM8916, where the base
address depends on the amount of RAM you have:

  <= 2.00 GiB RAM: 0x80000000
   = 3.00 GiB RAM: 0x40000000
   = 3.75 GiB RAM: 0x10000000
 (more does not fit into the 32-bit physical address space)

So, 0x10000000 will only end up being used on devices with 3.75 GiB RAM.

Can you add a note about this in the commit message maybe? We don't know
in advance which base address a device will use, so I think it's fine to
hardcode one of the choices by default. msm8916.dtsi does the same.

Thanks,
Stephan

> Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
> ---
>  arch/arm64/boot/dts/qcom/msm8953.dtsi | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/qcom/msm8953.dtsi b/arch/arm64/boot/dts/qcom/msm8953.dtsi
> index e7de7632669a..a3ba24ca599b 100644
> --- a/arch/arm64/boot/dts/qcom/msm8953.dtsi
> +++ b/arch/arm64/boot/dts/qcom/msm8953.dtsi
> @@ -174,10 +174,10 @@ scm: scm {
>  		};
>  	};
>  
> -	memory {
> +	memory@10000000 {
>  		device_type = "memory";
>  		/* We expect the bootloader to fill in the reg */
> -		reg = <0 0 0 0>;
> +		reg = <0 0x10000000 0 0>;
>  	};
>  
>  	pmu {
> 
> -- 
> 2.42.0
>