Re: [PATCH v4 6/8] dt-bindings: Add support for Amlogic GXBB SCPI Interface

[Sudeep Holla]

On 02/11/16 21:51, Rob Herring wrote:
> On Wed, Nov 2, 2016 at 5:20 PM, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
> > On Sat, Oct 29, 2016 at 11:39:05AM -0700, Olof Johansson wrote:
> > > Hi,
> > >
> > >
> > > On Wed, Oct 5, 2016 at 12:33 AM, Neil Armstrong <narmstrong@xxxxxxxxxxxx> wrote:
> > > > Acked-by: Rob Herring <robh@xxxxxxxxxx>
> > > > Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> > > > ---
> > > >  Documentation/devicetree/bindings/arm/arm,scpi.txt | 8 +++++---
> > > >  1 file changed, 5 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/arm/arm,scpi.txt b/Documentation/devicetree/bindings/arm/arm,scpi.txt
> > > > index faa4b44..04bc171 100644
> > > > --- a/Documentation/devicetree/bindings/arm/arm,scpi.txt
> > > > +++ b/Documentation/devicetree/bindings/arm/arm,scpi.txt
> > > > @@ -7,7 +7,7 @@ by Linux to initiate various system control and power operations.
> > > >
> > > >  Required properties:
> > > >
> > > > -- compatible : should be "arm,scpi"
> > > > +- compatible : should be "arm,scpi" or "amlogic,meson-gxbb-scpi"
> > >
> > > This doesn't seem right to document here. If anything you might want
> > > to have a table of more-specific-compatibles for specific
> > > implementations, but "arm,scpi" should still be the compatible of the
> > > node (just not the most specific one).
> >
> > I completely agree with you and I was pushing for a generic "arm,legacy-scpi"
> > compatible until this binding was acked by Rob.
>
> Just because I ack something, that doesn't mean don't review or
> comment on it further.

Sorry I didn't mean to say that. I was initially pushing for the generic
binding and since it was reworked many times already, I didn't want to
postpone any further just for sake of that. I completely understand that
component maintainers have to review the bindings too. So clearly it was
my mistake.

> > Anyways, I will add the generic compatible and post the changes.
> >
> > > Also, documenting it here indiciates that non-amlogic implementations
> > > can/should use that compatible, which is misleading.
> >
> > Agreed, it's better to keep them out of this generic binding document.
> >
> > > >  - mboxes: List of phandle and mailbox channel specifiers
> > > >           All the channels reserved by remote SCP firmware for use by
> > > >           SCPI message protocol should be specified in any order
> > > > @@ -60,7 +60,8 @@ A small area of SRAM is reserved for SCPI communication between application
> > > >  processors and SCP.
> > > >
> > > >  Required properties:
> > > > -- compatible : should be "arm,juno-sram-ns" for Non-secure SRAM on Juno
> > > > +- compatible : should be "arm,juno-sram-ns" for Non-secure SRAM on Juno,
> > > > +               or "amlogic,meson-gxbb-sram" for Amlogic GXBB SoC.
> > >
> > > Maybe you'd be better of with a meson-specific document that refers to
> > > these but with different compatible values.
> > >
> > > Come to think of it, the Juno-specific one maybe shouldn't be in
> > > arm,scpi at all, since that adds confusion here.
> > >
> > > It's somewhat confusing that ARM is both a platform, architecture and
> > > in some cases implementer of specific systems. :)
> >
> > Sorry for that, I will move all juno specific references in the binding
> > out of this document(except the examples, which I assume should be fine)
> >
> > > >  The rest of the properties should follow the generic mmio-sram description
> > > >  found in ../../sram/sram.txt
> > > > @@ -70,7 +71,8 @@ Each sub-node represents the reserved area for SCPI.
> > > >  Required sub-node properties:
> > > >  - reg : The base offset and size of the reserved area with the SRAM
> > > >  - compatible : should be "arm,juno-scp-shmem" for Non-secure SRAM based
> > > > -              shared memory on Juno platforms
> > > > +              shared memory on Juno platforms or
> > > > +              "amlogic,meson-gxbb-scp-shmem" for Amlogic GXBB SoC.
> > >
> > > Same here. It won't scale if all vendors are expected to add an entry here.
> >
> > I will rework the patches to address the concerns as I too did share same
> > concern.
>
> Guess I was optimistic that *every* platform wouldn't be different in
> some way. I should know better by now...

:)

--
Regards,
Sudeep