[PATCH 1/1] ARM: Exynos: Add generic compatible string

[Sachin Kamat]

On 25 February 2014 17:12, Arnd Bergmann <arnd at arndb.de> wrote:
> On Tuesday 25 February 2014, Olof Johansson wrote:
>> I disagree. I don't know what Samsung has in mind, but the revision of
>> the CPU doesn't have all that much to do with the rest of the SoC.
>> It's quite likely that some vendors (maybe not Samsung, but the same
>> concept applies) will ship 64-bit SoCs that are very similar to their
>> preceding 32-bit ones, same IP, similar busses, etc. I'm pretty sure
>> at least some vendors will do very close to that.
>
> Right.
>
>> So, if EXYNOS4 and EXYNOS5 can share a compatible value when they use
>> different CPUs, then there's no reason that whatever future 64-bit
>> ones can also share it.
>
> How about putting both 'samsung,exynos' and 'samsung,exynos4' in DT then
> and having the platform code match exynos4 and exynos5 but not exynos?
>
> That way, I think we are consistent and future-proof. Any code that needs
> to know if it's running on some exynos version can just check for the
> 'samsung,exynos' compatible value and that will work on both arm32 and
> arm64. Also, if we ever decide we want to run a 32-bit kernel on a 64-bit
> exynos, we can just add 'samsung,exynos6' (or whatever number that will
> be) to the list.
>
> My usual disclaimer for this: You should never ever consider actually
> running a 32-bit kernel on a 64-bit CPU, but at the same time there
> shouldn't be any reason why it won't work either, given that we require
> arm64 based systems to have all SoC specific code in drivers and we
> can use the same drivers on arm32.

Kukjin, Tomasz,

What is your opinion about Arnd's suggestion?

-- 
With warm regards,
Sachin