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

From: Sudeep Holla
Date: Thu Nov 03 2016 - 00:37:51 EST

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:

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

Guess I was optimistic that *every* platform wouldn't be different in
some way. I should know better by now...