Re: [PATCH v3 1/3] dt-bindings: mailbox: Add mediatek,gce-props.yaml

[AngeloGioacchino Del Regno]

Il 19/01/24 17:44, Conor Dooley ha scritto:
> Rob,
>
> On Fri, Jan 19, 2024 at 02:32:22PM +0800, Jason-JH.Lin wrote:
> > Add mediatek,gce-props.yaml for common GCE properties that is used for
> > both mailbox providers and consumers. We place the common property
> > "mediatek,gce-events" in this binding currently.
> >
> > The property "mediatek,gce-events" is used for GCE event ID corresponding
> > to a hardware event signal sent by the hardware or a sofware driver.
> > If the mailbox providers or consumers want to manipulate the value of
> > the event ID, they need to know the specific event ID.
> >
> > Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
> > ---
> >   .../bindings/mailbox/mediatek,gce-props.yaml  | 52 +++++++++++++++++++
>
> Is bindings/mailbox the correct directory to put this in?

Well, the GCE is a mailbox :-)

..but I get why you're asking... and I don't think that this should go to
arm/mediatek/ as it's really just only referring to extra properties for kind of
"special" mailbox client events...

Cheers,
Angelo

> >   1 file changed, 52 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,gce-props.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/mailbox/mediatek,gce-props.yaml b/Documentation/devicetree/bindings/mailbox/mediatek,gce-props.yaml
> > new file mode 100644
> > index 000000000000..68b519ff089f
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mailbox/mediatek,gce-props.yaml
> > @@ -0,0 +1,52 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/mailbox/mediatek,gce-props.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: MediaTek Global Command Engine Common Propertes
> > +
> > +maintainers:
> > +  - Houlong Wei <houlong.wei@xxxxxxxxxxxx>
> > +
> > +description:
> > +  The Global Command Engine (GCE) is an instruction based, multi-threaded,
> > +  single-core command dispatcher for MediaTek hardware. The Command Queue
> > +  (CMDQ) mailbox driver is a driver for GCE, implemented using the Linux
> > +  mailbox framework. It is used to receive messages from mailbox consumers
> > +  and configure GCE to execute the specified instruction set in the message.
> > +  We use mediatek,gce-mailbox.yaml to define the properties for CMDQ mailbox
> > +  driver. A device driver that uses the CMDQ driver to configure its hardware
> > +  registers is a mailbox consumer. The mailbox consumer can request a mailbox
> > +  channel corresponding to a GCE hardware thread to send a message, specifying
> > +  that the GCE thread to configure its hardware. The mailbox provider can also
> > +  reserved a mailbox channel to configure GCE hardware register by the spcific
> > +  GCE thread. This binding defines the common GCE properties for both mailbox
> > +  provider and consumers.
> > +
> > +properties:
> > +  mediatek,gce-events:
> > +    description:
> > +      GCE has an event table in SRAM, consisting of 1024 event IDs (0~1023).
> > +      Each event ID has a boolean event value with the default value 0.
> > +      The property mediatek,gce-events is used to obtain the event IDs.
> > +      Some gce-events are hardware-bound and cannot be changed by software.
> > +      For instance, in MT8195, when VDO0_MUTEX is stream done, VDO_MUTEX will
> > +      send an event signal to GCE, setting the value of event ID 597 to 1.
> > +      Similarly, in MT8188, the value of event ID 574 will be set to 1 when
> > +      VOD0_MUTEX is stream done.
> > +      On the other hand, some gce-events are not hardware-bound and can be
> > +      changed by software. For example, in MT8188, we can set the value of
> > +      event ID 855, which is not bound to any hardware, to 1 when the driver
> > +      in the secure world completes a task. However, in MT8195, event ID 855
> > +      is already bound to VDEC_LAT1, so we need to select another event ID to
> > +      achieve the same purpose. This event ID can be any ID that is not bound
> > +      to any hardware and is not yet used in any software driver.
> > +      To determine if the event ID is bound to the hardware or used by a
> > +      software driver, refer to the GCE header
> > +      include/dt-bindings/gce/<chip>-gce.h of each chip.
> > +    $ref: /schemas/types.yaml#/definitions/uint32-array
> > +    minItems: 1
> > +    maxItems: 1024
> > +
> > +additionalProperties: true
> > --
> > 2.18.0