[PATCH 10/10] arm: imx: imx8m: Add basic PSCI provider implementation

[Adam Ford]

On Wed, Dec 21, 2022 at 9:58 PM Marek Vasut <marex at denx.de> wrote:
>
> On 12/22/22 04:05, Adam Ford wrote:
> > On Wed, Dec 21, 2022 at 6:47 PM Marek Vasut <marex at denx.de> wrote:
> >>
> >> Implement basic PSCI provider to let OS turn CPU cores off and on,
> >> power off and restart the system and determine PSCI version. This
> >> is sufficient to remove the need for the ATF BL31 blob altogether.
> >>
> >> To make use of this functionality, active the following Kconfig options:
> >>    # CONFIG_PSCI_RESET is not set
> >>    CONFIG_ARMV8_MULTIENTRY=y
> >>    CONFIG_ARMV8_SET_SMPEN=y
> >>    CONFIG_ARMV8_SPL_EXCEPTION_VECTORS=y
> >>    CONFIG_ARMV8_EA_EL3_FIRST=y
> >>    CONFIG_ARMV8_PSCI=y
> >>    CONFIG_ARMV8_PSCI_CPUS_PER_CLUSTER=4
> >>    CONFIG_ARMV8_SECURE_BASE=0x970000
> >
> >   I am guessing 0x970000 was for the 8MP based on the previous location
> > of ATF.  Is that true?   If that's the case, can I assume that this
> > address would be  0x910000, 0x920000 and 0x960000 for the imx8mq,
> > imx8mm and imx8mn respectively?
>
> It was for MX8MP, but you can pick whichever address you want, since it
> is U-Boot that installs the SMC handlers, you are no longer forced to
> somehow try and accommodate custom not well fitting load address picked
> by some 3rd party binary blob.

I patched U-Boot's master with this series and I tried it on
imx8mn_beacon and imx8mm_beacon without success. I never even saw the
SPL message.  I tried to focus on the Nano since the boot ROM in that
one is more similar to that of the 8mp, but the behaviour was similar
to that of the Nano.  Are there any dependencies or should I have used
a specific starting branch?

adam