kernel_samsung_a34x-permissive/Documentation/devicetree/bindings/mailbox/mtk-gce.txt
2024-04-28 15:51:13 +02:00

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MediaTek GCE
===============
The Global Command Engine (GCE) is used to help read/write registers with
critical time limitation, such as updating display configuration during the
vblank. The GCE can be used to implement the Command Queue (CMDQ) driver.
CMDQ driver uses mailbox framework for communication. Please refer to
mailbox.txt for generic information about mailbox device-tree bindings.
Required properties:
- compatible: Can be one of the following strings:
"mediatek,mt6779-gce" for mt6799.
"mediatek,mt8173-gce" for mt8173.
"mediatek,mt2712-gce", "mediatek,mt8173-gce" for mt2712.
- reg: Address range of the GCE unit
- interrupts: The interrupt signal from the GCE block
- #mbox-cells: Should be 3.
<&phandle channel priority atomic_exec>
phandle: Label name of a gce node.
channel: Channel of mailbox. Be equal to the thread id of GCE.
priority: Priority of GCE thread.
atomic_exec: GCE processing continuous packets of commands in atomic
way.
Optional properties:
- clock: Clocks according to the common clock binding
- clock-names: Must be "gce" to stand for GCE clock
Required properties for a client device:
- mboxes: Client use mailbox to communicate with GCE, it should have this
property and list of phandle, mailbox specifiers.
- mediatek,gce-subsys: u32, specify the sub-system id which is corresponding
to the register address.
Some vaules of properties are defined in 'dt-bindings/gce/mtxxxx-gce.h', e.g.,
mt8173-gce.h. Such as sub-system ids, thread priority, event ids.
Example:
gce: gce@10212000 {
compatible = "mediatek,mt8173-gce";
reg = <0 0x10212000 0 0x1000>;
interrupts = <GIC_SPI 135 IRQ_TYPE_LEVEL_LOW>;
clocks = <&infracfg CLK_INFRA_GCE>;
clock-names = "gce";
thread-num = CMDQ_THR_MAX_COUNT;
#mbox-cells = <3>;
};
Example for a client device:
mmsys: clock-controller@14000000 {
compatible = "mediatek,mt8173-mmsys";
mboxes = <&gce 0 CMDQ_THR_PRIO_LOWEST 1>,
<&gce 1 CMDQ_THR_PRIO_LOWEST 1>;
mediatek,gce-subsys = <SUBSYS_1400XXXX>;
mutex-event-eof = <CMDQ_EVENT_MUTEX0_STREAM_EOF
CMDQ_EVENT_MUTEX1_STREAM_EOF>;
...
};