Re: [PATCH] ARM: rpi: parse memory from vc fdt

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 10.01.23 20:32, Marcin Niestroj wrote:
> From: Marcin Niestroj <m.niestroj@emb.dev>
> 
> Currently for RaspberryPi platform there is only one memory bank
> created, based on information fetched over mailbox. This is fine for
> booting Barebox, but unfortunately all the other memory banks are not
> propagated to Linux during boot, thus cannot be utilized. In fact, even
> when using /vc.dtb as device-tree for Linux, all memory nodes in FDT are
> deleted and new ones are created by Barebox by memory fixup mechanism,
> using exising RAM information. As a result RaspberryPi 4 boots Linux
> with 1GB RAM available, instead of 2GB (2 banks, each 1GB).
> 
> At the end of VideoCore FDT parsing, do the same as of_probe_memory() in
> mem_initcall does, but for VideoCore provided devicetree/memory
> information. During Linux boot this information is used for memory fixup
> mechanism and in case of RaspberryPi 4 this results in 2 memory banks
> being propagated:
> 
>   # ls /proc/device-tree/memory*
>   /proc/device-tree/memory@0:
>   device_type  name         reg
> 
>   /proc/device-tree/memory@40000000:
>   device_type  name         reg
> 
> Signed-off-by: Marcin Niestroj <m.niestroj@emb.dev>

Thanks for your patch. I suggest this be applied to master.

I think it may be worthwhile in future to only query the mailbox
interface for memory in PBL (lowlevel.c) for use as early mem and
depend solely on DT in barebox proper.

> ---
>  arch/arm/boards/raspberry-pi/rpi-common.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)

> +		err = of_add_memory(memory, false);
> +		if (err)
> +			ret = err;

No one does anything wither either err or ret, so you can drop that.
Anyways:

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> +	}
> +
>  out:
>  	if (root)
>  		of_delete_node(root);

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