[PATCH v4 1/2] arm: rmobile: Add PRR CPU ID macros for RZ/G2[HMNE]

[Biju Das]

Hi Marek,

Thanks for the feedback.

> Subject: Re: [PATCH v4 1/2] arm: rmobile: Add PRR CPU ID macros for
> RZ/G2[HMNE]
>
> On 10/1/20 12:36 PM, Biju Das wrote:
> [...]
>
> > diff --git a/arch/arm/mach-rmobile/include/mach/rmobile.h
> > b/arch/arm/mach-rmobile/include/mach/rmobile.h
> > index a50249dc96..bd4bd01b75 100644
> > --- a/arch/arm/mach-rmobile/include/mach/rmobile.h
> > +++ b/arch/arm/mach-rmobile/include/mach/rmobile.h
> > @@ -27,6 +27,10 @@
> >  /* PRR CPU IDs */
> >  #define RMOBILE_CPU_TYPE_SH73A00x37
> >  #define RMOBILE_CPU_TYPE_R8A77400x40
> > +#define RMOBILE_CPU_TYPE_R8A774A10x52
>
> The problem here is that this is the same as
> #define RMOBILE_CPU_TYPE_R8A7796   0x52
>
> So if you use that ^ in the code, you cannot discern it from
> RMOBILE_CPU_TYPE_R8A774A1 .

But this value is same as per the hardware manual, see the definitions in linux[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/renesas/renesas-soc.c?h=v5.9-rc7#n114
Please correct me, if this macros are not as per hardware manual.

> We really need to find a way to tell these two apart first, e.g. by checking the
> bootrom, and then use it in U-Boot all over the place.

Yes, I agree we need to differentiate them. Different ways I can think of is

1) Bootrom level
2) Checking some IP register which is present in RCar and not in RZ/G2
3) Compatible SoC string from TFA
4) TFA there will be separation for RZ/G2 SoC and RCar Gen3 SoC, So populate some dtfragment for RCar/RZG2 SoC similar to dram and u-boot handling it for SoC separation.
5) Use compile time macros in U-boot.

Please let me you know, which is the best way to go forward and also let me know, if you have any other ideas in your mind.

Regards,
Biju





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