[RFC PATCH] arm64: dts: rockchip: Make preparations for per-RK3588-variant OPPs

[Jonas Karlman]

Hi Alexey and Dragan,

On 2024-05-30 21:31, Dragan Simic wrote:
> Hello Alexey,
> 

[snip]

>>>>> That way we'll have no roadblocks if, at some point, we end up with
>>>>> having
>>>>> different OPPs defined for the RK3588 and the RK3588S variants.  Or
>>>>> maybe
>>>>> even for the RK3582, which we don't know much about yet.
>>>>
>>>> Guess we'll deal with that one once we stumble upon an actual RK3582
>>>> board out in the wild and heading to the mainline kernel tree :)
>>>
>>> Of course, that was just an example for the future use.
>>
>> In fact, I've just discovered that Radxa has recently released Rock 5C
>> Lite which is based on RK3582, and starts at just $29 for the 1GB
>> version, making it interesting for tinkering. Especially given that
>> its GPU, one of the big-core clusters and one of the VPU cores seem to
>> be disabled in software (u-boot) rather than in hardware, which means
>> there is some chance that a particular SoC specimen would actually
>> have them in a working condition and possible to re-enable at no cost.
>> Ordered myself one to investigate :)
> 
> Yes, I also saw the RK3582-based ROCK 5C Lite a couple of days ago. :)
> It seems that the disabled IP blocks are detected as defective during
> the manufacturing, which means that they might work correctly, or might
> actually misbehave.  It seems similar to the way old three-core AMD
> Phenom II CPUs could sometimes be made quad-core.
> 

I can confirm that the RK3582 include ip-state in OTP indicating
unusable cores, any unusable cpu core cannot be taken online and stalls
Linux kernel a few extra seconds during boot.

Started working on a patch for U-Boot to remove any broken cpu core
and/or cluster nodes, similar to what vendor U-Boot does, adopted to
work with a mainline DT for RK3588.

On one of my ROCK 5C Lite board one of the cpu cores is unusable, U-Boot
removes the related cpu cluster nodes. On another ROCK 5C Lite board one
rkvdec core is only marked unusable and all cpu cores can be taken
online, U-Boot does nothing in this case. Guessing we should apply
similar policy as vendor U-Boot and disable cores anyway.

Following commit contains early work-in-progress and some debug output.

https://github.com/Kwiboo/u-boot-rockchip/commit/8cdf606e616baa36751f3b4adcfaefc781126c8c

Booting ROCK 5C Lite boards using U-Boot generic-rk3588_defconfig:

ROCK 5C Lite v1.1 (RK3582 with 1 bad cpu core):

  cpu-code: 3582
  cpu-version: 08 10
  data: fe 21
  package: 11
  specification: 01
  ip-state: 10 00 00
  bad-state: cpu core 4

ROCK 5C Lite v1.1 (RK3582 with 1 bad rkvdec core):

  cpu-code: 3582
  cpu-version: 08 00
  data: fe 21
  package: 11
  specification: 01
  ip-state: 00 80 00
  bad-state: rkvdec core 1

Regards,
Jonas