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: can be "mediatek,mt8173-gce", "mediatek,mt8183-gce" or 13 "mediatek,mt6779-gce". 14- reg: Address range of the GCE unit 15- interrupts: The interrupt signal from the GCE block 16- clock: Clocks according to the common clock binding 17- clock-names: Must be "gce" to stand for GCE clock 18- #mbox-cells: Should be 2. 19 <&phandle channel priority> 20 phandle: Label name of a gce node. 21 channel: Channel of mailbox. Be equal to the thread id of GCE. 22 priority: Priority of GCE thread. 23 24Required properties for a client device: 25- mboxes: Client use mailbox to communicate with GCE, it should have this 26 property and list of phandle, mailbox specifiers. 27Optional properties for a client device: 28- mediatek,gce-client-reg: Specify the sub-system id which is corresponding 29 to the register address, it should have this property and list of phandle, 30 sub-system specifiers. 31 <&phandle subsys_number start_offset size> 32 phandle: Label name of a gce node. 33 subsys_number: specify the sub-system id which is corresponding 34 to the register address. 35 start_offset: the start offset of register address that GCE can access. 36 size: the total size of register address that GCE can access. 37 38Some vaules of properties are defined in 'dt-bindings/gce/mt8173-gce.h', 39'dt-binding/gce/mt8183-gce.h' or 'dt-bindings/gce/mt6779-gce.h'. Such as 40sub-system ids, thread priority, event ids. 41 42Example: 43 44 gce: gce@10212000 { 45 compatible = "mediatek,mt8173-gce"; 46 reg = <0 0x10212000 0 0x1000>; 47 interrupts = <GIC_SPI 135 IRQ_TYPE_LEVEL_LOW>; 48 clocks = <&infracfg CLK_INFRA_GCE>; 49 clock-names = "gce"; 50 #mbox-cells = <2>; 51 }; 52 53Example for a client device: 54 55 mmsys: clock-controller@14000000 { 56 compatible = "mediatek,mt8173-mmsys"; 57 mboxes = <&gce 0 CMDQ_THR_PRIO_LOWEST>, 58 <&gce 1 CMDQ_THR_PRIO_LOWEST>; 59 mutex-event-eof = <CMDQ_EVENT_MUTEX0_STREAM_EOF 60 CMDQ_EVENT_MUTEX1_STREAM_EOF>; 61 mediatek,gce-client-reg = <&gce SUBSYS_1400XXXX 0x3000 0x1000>, 62 <&gce SUBSYS_1401XXXX 0x2000 0x100>; 63 ... 64 }; 65