Re: [PATCH V10 7/7] arm64: dts: qcom: sa8775p: Add CPU OPP tables to scale DDR/L3
From: Dmitry Baryshkov
Date: Wed Mar 26 2025 - 13:49:41 EST
On Mon, Mar 24, 2025 at 06:32:03PM +0000, Raviteja Laggyshetty wrote:
> From: Jagadeesh Kona <quic_jkona@xxxxxxxxxxx>
>
> Add OPP tables required to scale DDR and L3 per freq-domain
> on SA8775P platform.
>
> If a single OPP table is used for both CPU domains, then
> _allocate_opp_table() won't be invoked for CPU4 but instead
> CPU4 will be added as device under the CPU0 OPP table. Due
> to this, dev_pm_opp_of_find_icc_paths() won't be invoked for
> CPU4 device and hence CPU4 won't be able to independently scale
> it's interconnects. Both CPU0 and CPU4 devices will scale the
> same ICC path which can lead to one device overwriting the BW
> vote placed by other device. Hence CPU0 and CPU4 require separate
> OPP tables to allow independent scaling of DDR and L3 frequencies
> for each CPU domain, with the final DDR and L3 frequencies being
> an aggregate of both.
>
> Co-developed-by: Shivnandan Kumar <quic_kshivnan@xxxxxxxxxxx>
> Signed-off-by: Shivnandan Kumar <quic_kshivnan@xxxxxxxxxxx>
> Signed-off-by: Raviteja Laggyshetty <quic_rlaggysh@xxxxxxxxxxx>
> Signed-off-by: Jagadeesh Kona <quic_jkona@xxxxxxxxxxx>
> ---
> arch/arm64/boot/dts/qcom/sa8775p.dtsi | 210 ++++++++++++++++++++++++++
> 1 file changed, 210 insertions(+)
>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
--
With best wishes
Dmitry