On 5 March 2014 17:42, Tomasz Figa <tomasz.figa@xxxxxxxxx> wrote: > On 05.03.2014 09:25, Sachin Kamat wrote: >> >> On 25 February 2014 17:12, Arnd Bergmann <arnd@xxxxxxxx> 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? >> > > I would still prefer introducing a generic string for 32-bit Exynos SoCs, > but I don't think it really matters a lot. I guess we can stick to just > exynos4 and exynos5 compatible strings then, as long as we can merge the > "board"-files and common.c together, since the code is pretty much > SoC-independent now. OK. Just wanted a confirmation before sending out the patches. Thanks. -- With warm regards, Sachin -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
