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

AngeloGioacchino Del Regno
2024-01-22T10:38:19Z

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@mediatek.com>
>> ---
>> .../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@mediatek.com>
>> +
>> +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
>>