Re: [GIT PULL 3/4] Rockchip dts32 changes for 4.14

[Heiko Stuebner <heiko@sntech.de>]

Am Mittwoch, 16. August 2017, 23:10:32 CEST schrieb Arnd Bergmann:
> On Sun, Aug 6, 2017 at 11:50 AM, Heiko Stuebner <heiko@sntech.de> wrote:
> > The following changes since commit 5771a8c08880cdca3bfb4a3fc6d309d6bba20877:
> >
> >   Linux v4.13-rc1 (2017-07-15 15:22:10 -0700)
> >
> > are available in the git repository at:
> >
> >   git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git tags/v4.14-rockchip-dts32-1
> >
> > for you to fetch changes up to 0f4dc7e154d054303c4dd6b5c3e3207f9a7f8714:
> >
> >   ARM: dts: rockchip: fix property-ordering in rv1108 mmc nodes (2017-07-22 22:41:35 +0200)
> >
> > ----------------------------------------------------------------
> > Removal of the deprectated num-slots property from all Rockchip dw-mmc
> > nodes. The rv1108 gains support for sd-cards on the evaluation board and
> > the general nodes get a bit of cosmetic. On rk3288 the evb gains support
> > saradc and the adc-key connected to it while some more boards also get
> > their mali gpu enabled (fennec, evb, tinker).
> >
> > The biggest set of changes can be found on the rk3228/rk3229 combo this
> > time. It gets core support for efuse, sdmmc, sdio, io-domans and spdif
> > as well as a separate rk3229.dtsi that will keep the slight differences
> > between the two brothers rk3228/rk3229. The evaluation board also gets
> > some attention and abled nodes (regulators, io-domains, emmc, tsadc keys)
> >
> > But I think the most interesting change is the cpu enable-method for it.
> > Instead of using the older in-kernel method, we're now also moving to
> > handling this in firmware via the psci interface on 32bit Rockchip socs.
> > In a recently merged pull request [0] support for the rk3228/rk3229 was
> > added to OP-TEE including the psci support and it seems supporting other
> > 32bit Rockchip socs that way is also planned for the future.
> >
> > [0] https://github.com/OP-TEE/optee_os/pull/1666
> 
> Nice tag description!
> 
> What is the migration strategy for the 32-bit chips moving to psci?
> Does this mean that you have to update the bootloader in sync with the
> kernel now?

so right now, only the rk3228/rk3229 combo uses psci alone
(and not the kernel-level smp implementation of other rockchip socs).
So for that there is no migration needed.

For the "legacy" socs (if that planned psci enablement does actually
happen), I'd guess a supporting bootloader would just re-set the
enable-method in the cpu nodes to psci and enable a yet-to-add
psci node.

So my personal migration strategy would be to leave it like it is
on the kernel dt-side and let updated firmware wiggle the
devicetree into form :-) .

That way backwards-compatibility always stays in place and we
don't require lock-step upgrades of bootloaders ... especially as
the plethora of old Rockchip boards out there, sometimes even
uses completely proprietary loaders.


Heiko