Re: [PATCH 9/9] ARM: Layerscape: LS1046a: add PSCI node

[Sascha Hauer <s.hauer@pengutronix.de>]

Hi Ahmad,

On Mon, Oct 21, 2024 at 09:33:23AM +0200, Ahmad Fatoum wrote:
> Hello Sascha,
> 
> On 21.10.24 09:21, Sascha Hauer wrote:
> > Unlike other SoCs the LS1046a upstream dtsi files do not have a PSCI
> > node. Add one for barebox and Linux to find the PSCI support.
> > 
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> 
> I am wondering how powering CPUs on and off worked before?
> I see no enable-method = "spin-table" in the kernel DT for the SoC.

The PPA is PSCI compatible. The barebox PPA adapter called
of_psci_fixup() to register a PSCI node.

> 
> Anyhow, barebox should probably fixup enable-method = "psci" into each
> CPU in /cpus in the kernel DT.

This is already done in of_psci_fixup().

The PSCI node in the barebox dts is only needed to probe the psci-client
driver which in turn creates/fixups the PSCI node for the kernel. We
already know that we started the TF-A. I thought about using this
knowledge to register the PSCI client driver without explicitly creating
a device node for it, but on the other hand there isn't too much gain in
doing so, so I just created a node for now.

Sascha

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