On 06/24/2016 09:15 PM, Masahiro Yamada wrote: > Hi York, > > 2016-06-21 1:30 GMT+09:00 york sun <york....@nxp.com>: >> On 06/19/2016 03:34 AM, André Przywara wrote: >>> Hi, >>> >>> On 19/06/16 09:57, Masahiro Yamada wrote: >>>> 2016-06-18 18:40 GMT+09:00 Linus Walleij <linus.wall...@linaro.org>: >>>>> On Fri, Jun 17, 2016 at 2:51 PM, Masahiro Yamada >>>>> <yamada.masah...@socionext.com> wrote: >>>>> >>>>>> There are two enable methods supported by ARM64 Linux; psci and >>>>>> spin-table. The latter is simpler and easier to use for quick SoC >>>>>> bring-up. >>>>>> >>>>>> So, I used the spin-table for my first ARMv8 SoC porting, but I >>>>>> found its support in U-Boot was poor. It is true there exists a >>>>>> code fragment for the spin code in arch/arm/cpu/armv8/start.S, >>>>>> but I see some problems: >>>>> >>>>> Is part of the motivation for this approach to boot an ARMv8 system >>>>> without using the ARM Trusted Firmware? >>>>> >>>>> Yours, >>>>> Linus Walleij >>>> >>>> Yes, exactly. >>>> >>>> It would be the best choice >>>> to switch over to PSCI with ATF in a long run, >>>> but, I decided to use spin-table for the initial SoC bring-up >>>> because of tight schedule. >>> >>> So if you don't have an ATF port ready, why not use U-Boot's PSCI >>> implementation meanwhile? I think there are efforts underway to make >>> PSCI enablement for random new boards a walk in the park (by making the >>> PSCI support as generic as possible, CCing Chen-Yu for this). >>> >>> IIRC the spin-table boot method was just introduced to cope with cores >>> that don't have EL3 and thus cannot provide PSCI services the normal way >>> (and that don't want to or cannot sacrifice EL2 for that). >>> So I am a bit wary of proliferating this SMP method. >>> >>> Wouldn't it be better to help making U-Boot's PSCI stack as easy to use >>> as possible? I don't see technical reasons that adding PSCI support for >>> a board should be harder or more involved than adding spin-table support >>> - in the end you need to tell it about the SMP pen, maybe providing (or >>> faking?) reset and shutdown for 0.2 compliance. >>> >> >> We have a team working on PSCI for ARMv8. The patches are floating and >> need some minor fix. With these patches, PSCI will be used instead of >> spin-table. However, a trusted firmware (or other kind) is required. >> > > > That's great. > > > So, what should we do about this patch? > > > I admit PSCI with ATF is the best way in the end, > but I believe having a simpler alternative should not hurt. >
I support using spin table as alternative. I see you already sent out v2 patch. It would be easier to maintain if we consolidate existing code with generic code. York _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
