1MediaTek GCE
2===============
3
4The Global Command Engine (GCE) is used to help read/write registers with
5critical time limitation, such as updating display configuration during the
6vblank. The GCE can be used to implement the Command Queue (CMDQ) driver.
7
8CMDQ driver uses mailbox framework for communication. Please refer to
9mailbox.txt for generic information about mailbox device-tree bindings.
10
11Required properties:
12- compatible: Must be "mediatek,mt8173-gce"
13- reg: Address range of the GCE unit
14- interrupts: The interrupt signal from the GCE block
15- clock: Clocks according to the common clock binding
16- clock-names: Must be "gce" to stand for GCE clock
17- #mbox-cells: Should be 3.
18	<&phandle channel priority atomic_exec>
19	phandle: Label name of a gce node.
20	channel: Channel of mailbox. Be equal to the thread id of GCE.
21	priority: Priority of GCE thread.
22	atomic_exec: GCE processing continuous packets of commands in atomic
23		way.
24
25Required properties for a client device:
26- mboxes: Client use mailbox to communicate with GCE, it should have this
27  property and list of phandle, mailbox specifiers.
28- mediatek,gce-subsys: u32, specify the sub-system id which is corresponding
29  to the register address.
30
31Some vaules of properties are defined in 'dt-bindings/gce/mt8173-gce.h'. Such as
32sub-system ids, thread priority, event ids.
33
34Example:
35
36	gce: gce@10212000 {
37		compatible = "mediatek,mt8173-gce";
38		reg = <0 0x10212000 0 0x1000>;
39		interrupts = <GIC_SPI 135 IRQ_TYPE_LEVEL_LOW>;
40		clocks = <&infracfg CLK_INFRA_GCE>;
41		clock-names = "gce";
42		thread-num = CMDQ_THR_MAX_COUNT;
43		#mbox-cells = <3>;
44	};
45
46Example for a client device:
47
48	mmsys: clock-controller@14000000 {
49		compatible = "mediatek,mt8173-mmsys";
50		mboxes = <&gce 0 CMDQ_THR_PRIO_LOWEST 1>,
51			 <&gce 1 CMDQ_THR_PRIO_LOWEST 1>;
52		mediatek,gce-subsys = <SUBSYS_1400XXXX>;
53		mutex-event-eof = <CMDQ_EVENT_MUTEX0_STREAM_EOF
54				CMDQ_EVENT_MUTEX1_STREAM_EOF>;
55
56		...
57	};
58