Re: [PATCH v2] drivers: firmware: psci: unify enable-method binding on ARM {64,32}-bit systems

[Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>]

On Tuesday 26 April 2016 11:42:58 Sudeep Holla wrote:
> On 22/04/16 16:18, Sudeep Holla wrote:
> > Currently ARM CPUs DT bindings allows different enable-method value for
> > PSCI based systems. On ARM 64-bit this property is required and must be
> > "psci" while on ARM 32-bit systems this property is optional and must
> > be "arm,psci" if present.
> >
> > However, "arm,psci" has always been the compatible string for the PSCI
> > node, and was never intended to be the enable-method. So this is a bug
> > in the binding and not a deliberate attempt at specifying 32-bit
> > differently.
> >
> > This is problematic if 32-bit OS is run on 64-bit system which has
> > "psci" as enable-method rather than the expected "arm,psci".
> >
> > So let's unify the value into "psci" and remove support for "arm,psci"
> > before it finds any users.
> >
> > Reported-by: Soby Mathew <Soby.Mathew-5wv7dgnIgG8@public.gmane.org>
> > Cc: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> > Acked-by: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>
> > Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>
> > Signed-off-by: Sudeep Holla <sudeep.holla-5wv7dgnIgG8@public.gmane.org>
> > ---
> >   Documentation/devicetree/bindings/arm/cpus.txt | 1 -
> >   drivers/firmware/psci.c                        | 2 +-
> >   2 files changed, 1 insertion(+), 2 deletions(-)
> >
> > v2->v1:
> >       - Added Mark and Lorenzo's ACKs
> >       - Updated commit message to specify that it also conflicts with
> >         PSCI compatible(from Mark's reply on the thread)
> >
> > Hi ARM-SoC guys,
> >
> > Can you please pick up this single fix for PSCI binding/driver for v4.6 ?
> >
> 
> Gentle ping to include this in next round of arm-soc fixes. It would be
> good to get this fixed before v4.6 as we don't want to have user of the
> binding which we want to remove in the release.
> 

Applied to the fixes branch. I have to admit that I don't understand
how the compatible string is really used here, so I have to trust that
this cannot break any existing machine.

	Arnd
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