Re: [PATCH v4 1/1] hw/arm/sbsa-ref: Enable CPU cluster on ARM sbsa machine

[Marcin Juszkiewicz]

W dniu 26.04.2024 o 09:35, Xiong Yining pisze:
> From: xiongyining1480<xiongyining1480@phytium.com.cn>
>
> Enable CPU cluster support on SbsaQemu platform, so that users can
> specify a 4-level CPU hierarchy sockets/clusters/cores/threads. And
> this topology can be passed to the firmware through DT cpu-map.
>
> Signed-off-by: Xiong Yining<xiongyining1480@phytium.com.cn>
> tested-by: Marcin Juszkiewicz<marcin.juszkiewicz@linaro.org>

I had some thinking about it recently. This patch exported whole 
/cpus/cpu-map/ tree which we then parse in TF-A to get amount of 
sockets/clusters/cores/threads.

Why not export them directly? Kind of:

        cpus {
                topology {
                        threads = <0x01>;
                        cores = <0x04>;
                        clusters = <0x01>;
                        sockets = <0x01>;
                };

It gives everything we need.

Had some thinking about exporting amount of cores per cluster (8 now, 
virt uses 16 which is architecture maximum now) in case we would use it 
in generation of PPTT in EDK2.