Re: [PATCH] arm64: dts: renesas: r8a78000: Add PSCI node

[Marek Vasut <marek.vasut@mailbox.org>]

On 5/14/26 1:31 PM, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [High] Missing 'enable-method' in CPU nodes prevents SMP bring-up.
> --
> 
> commit 0e20af8dd1fbf54360d3f87985cba2a59a5ee08f
> Author: Marek Vasut <marek.vasut+renesas@mailbox.org>
> arm64: dts: renesas: r8a78000: Add PSCI node
> 
> This commit adds the PSCI node to the r8a78000 device tree to describe SMC
> based access. This enables interaction with the TFA BL31 PSCI provider for
> tasks such as CPU power management.
> 
>> diff --git a/arch/arm64/boot/dts/renesas/r8a78000.dtsi b/arch/arm64/boot/dts/renesas/r8a78000.dtsi
>> index 4c97298fa7634..9e759ea46ee20 100644
>> --- a/arch/arm64/boot/dts/renesas/r8a78000.dtsi
>> +++ b/arch/arm64/boot/dts/renesas/r8a78000.dtsi
> 
> [ ... ]
> 
>> @@ -665,6 +665,11 @@ extalr_clk: extalr-clk {
>>   		/* clock-frequency must be set on board */
>>   	};
>>   
>> +	psci {
>> +		compatible = "arm,psci-1.0";
>> +		method = "smc";
>> +	};
>> +
> 
> Does this also require updating the CPU nodes to actually use PSCI?
> 
> Looking at the ARM64 SMP bring-up in arch/arm64/kernel/cpu_ops.c, the kernel
> relies on cpu_read_enable_method() to determine how to wake up secondary
> CPUs. It expects an enable-method property in the device tree for each CPU
> node:
> 
> arch/arm64/kernel/cpu_ops.c:cpu_read_enable_method() {
>          ...
>          dn = of_get_cpu_node(cpu, NULL);
>          ...
>          enable_method = of_get_property(dn, "enable-method", NULL);
>          if (!enable_method) {
>                  ...
>          }
>          ...
> }
> 
> Without adding enable-method = "psci" to the cpu nodes in r8a78000.dtsi,
> does this cause an SMP regression where the system fails to initialize
> secondary cores and boots as a single-core system?
PSCI is used here to power off / reboot the system, SMP enablement is a 
separate topic and a separate patch.