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

[Adam Ford]

On Mon, Jan 2, 2023 at 5:41 PM Marek Vasut <marex at denx.de> wrote:
>
> On 1/2/23 17:44, Adam Ford wrote:
> > 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?
>
> Nope . But if you don't even see output from SPL, that's where I would
> start looking. Do you see output from SPL without this series ? Note
> that bulk of this series content applies to U-Boot proper, not SPL so far.

Without the patch series the generated flash.bin file booted both the
Mini and the Nano just fine.  I have a pending 8m plus that I can also
try, since that is what you used.  I just wanted to make sure I was
starting from the right place before I went too far with it.


adam