[PATCH 3/3] arm64: dts: rockchip: Add Radxa E52C

[Dragan Simic]

Hello Marc,

On 2024-12-23 10:39, Marc Zyngier wrote:
> On Sun, 22 Dec 2024 03:03:55 +0000,
> FUKAUMI Naoki <naoki at radxa.com> wrote:
>> 
>> Radxa E52C is a compact network computer[1] based on the Rockchip
>> RK3582 SoC:
>> 
>> - Dual Cortex-A76 and quad Cortex-A55 CPU
> 
> So you have *two* big cores.
> 
>> - 5TOPS NPU
>> - 2GB/4GB/8GB LPDDR4 RAM
>> - 16GB/32GB/64GB on-board eMMC
>> - microSD card slot
>> - USB 3.0 Type-A HOST port
>> - USB Type-C debug port
>> - USB Type-C power port (5V only)
>> - 2x 2.5GbE ports
>> 
>> [1] https://radxa.com/products/network-computer/e52c
>> 
>> Signed-off-by: FUKAUMI Naoki <naoki at radxa.com>
>> ---
>>  arch/arm64/boot/dts/rockchip/Makefile         |   1 +
>>  .../boot/dts/rockchip/rk3582-radxa-e52c.dts   | 729 
>> ++++++++++++++++++
>>  2 files changed, 730 insertions(+)
>>  create mode 100644 arch/arm64/boot/dts/rockchip/rk3582-radxa-e52c.dts
> 
> [...]
> 
>> +&cpu_b0 {
>> +	cpu-supply = <&vdd_cpu_big0_s0>;
>> +};
>> +
>> +&cpu_b1 {
>> +	cpu-supply = <&vdd_cpu_big0_s0>;
>> +};
>> +
>> +&cpu_b2 {
>> +	cpu-supply = <&vdd_cpu_big1_s0>;
>> +};
>> +
>> +&cpu_b3 {
>> +	cpu-supply = <&vdd_cpu_big1_s0>;
>> +};
> 
> And yet you configure 4. If your HW only has 2 A76s, surely something
> should remove these cores for this platform rather than keep them
> around.

Indeed, U-Boot will do that, based on the efuses that contain the
data required to determine which CPU cores (and/or clusters) are
defective and need to be marked as disabled.

Maybe we should add a comment block above the "cpu_b0" node, to
describe that a bit better.  Perhaps something like this:

   /*
    * In the Rockchip RK3582 SoC, some CPU cores end up disabled
    * and unused because they're marked in the efuses as defective.
    * The disabling in the DT is performed by the boot loader.
    */