linux-kernel - Re: [PATCH v2 2/4] dt-bindings: mailbox: mediatek: gce-mailbox: Add reference to gce-props.yaml

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Message-ID: <8c4004d5b6f68dc096aaf2a537e429c310b60c08.camel@mediatek.com>
Date: Wed, 10 Jan 2024 16:36:20 +0000
From: Jason-JH Lin (林睿祥) <Jason-JH.Lin@...iatek.com>
To: "conor@...nel.org" <conor@...nel.org>
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Subject: Re: [PATCH v2 2/4] dt-bindings: mailbox: mediatek: gce-mailbox: Add
 reference to gce-props.yaml

Hi Conor,

Thanks for the reviews.

On Wed, 2024-01-10 at 10:36 +0000, Conor Dooley wrote:
> On Wed, Jan 10, 2024 at 02:35:30PM +0800, Jason-JH.Lin wrote:
> > 1. Add "Provider" to the title to make it clearer.
> > 2. Add reference to gce-props.yaml for adding mediatek,gce-events
> > property.
> 
> I can see this from the diff. There's still no explanation here as to
> why the mailbox provider needs to have a gce-event id. NAK until you
> can
> explain that.
> 
Sorry for missing the reason in commit message, I'll add it in the next
version.

There are 2 reasons why the mailbox provider needs gce-events:
1. The mailbox provider here is CMDQ mailbox driver. It configures GCE
hardware register by CPU directly. If we want to set the default value
from 0 to 1 for specific gce-events during the initialization of CMDQ
driver. We need to tell CMDQ driver what gce-events need to be set and
I think such GCE hardware setting can get from its device node.

2. We'll have the secure CMDQ mailbox driver in the future patch [1].
It will request or reserve a mailbox channel, which is a dedicate GCE
thread, as a secure IRQ handler. This GCE thread executes a looping
instruction set that keeps waiting for the gce-event set from another
GCE thread in the secure world. So we also need to tell the CMDQ driver
what gce-event need to be waited.


[1] cmdq_sec_irq_notify_start() is where the GCE thread is requested to
prepare a looping instruction set to wait for the gce-event.
- 
https://patchwork.kernel.org/project/linux-mediatek/patch/20231222045228.27826-9-jason-jh.lin@mediatek.com/

Regards,
Jason-JH.Lin

> Cheers,
> Conor.
> 
> > 
> > Signed-off-by: Jason-JH.Lin <jason-jh.lin@...iatek.com>
> > ---
> >  .../devicetree/bindings/mailbox/mediatek,gce-mailbox.yaml   | 6
> > ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/mailbox/mediatek,gce-
> > mailbox.yaml
> > b/Documentation/devicetree/bindings/mailbox/mediatek,gce-
> > mailbox.yaml
> > index cef9d7601398..728dc93117a6 100644
> > --- a/Documentation/devicetree/bindings/mailbox/mediatek,gce-
> > mailbox.yaml
> > +++ b/Documentation/devicetree/bindings/mailbox/mediatek,gce-
> > mailbox.yaml
> > @@ -4,7 +4,7 @@
> >  $id: 
> > http://devicetree.org/schemas/mailbox/mediatek,gce-mailbox.yaml#
> >  $schema: http://devicetree.org/meta-schemas/core.yaml#
> >  
> > -title: Mediatek Global Command Engine Mailbox
> > +title: MediaTek Global Command Engine Mailbox Provider
> >  
> >  maintainers:
> >    - Houlong Wei <houlong.wei@...iatek.com>
> > @@ -57,6 +57,8 @@ required:
> >    - clocks
> >  
> >  allOf:
> > +  - $ref: mediatek,gce-props.yaml
> > +
> >    - if:
> >        not:
> >          properties:
> > @@ -67,7 +69,7 @@ allOf:
> >        required:
> >          - clock-names
> >  
> > -additionalProperties: false
> > +unevaluatedProperties: false
> >  
> >  examples:
> >    - |
> > -- 
> > 2.18.0
> >