linux-libre/Documentation/devicetree/bindings/mailbox/hisilicon,hi6220-mailbox.txt

Hisilicon Hi6220 Mailbox Driver
===============================

Hisilicon Hi6220 mailbox supports up to 32 channels. Each channel
is unidirectional with a maximum message size of 8 words. I/O is
performed using register access (there is no DMA) and the cell
raises an interrupt when messages are received.

Mailbox Device Node:
====================

Required properties:
--------------------
- compatible:		Shall be "hisilicon,hi6220-mbox"
- reg:			Contains the mailbox register address range (base
			address and length); the first item is for IPC
			registers, the second item is shared buffer for
			slots.
- #mbox-cells:		Common mailbox binding property to identify the number
			of cells required for the mailbox specifier. Must be 3.
			<&phandle slot_id dst_irq ack_irq>
			  phandle: Label name of mailbox controller
			  slot_id: Slot id used either for TX or RX
			  dst_irq: IRQ identifier index number which used by MCU
			  ack_irq: IRQ identifier index number with generating a
			           TX/RX interrupt to application processor,
				   mailbox driver uses it to acknowledge interrupt
- interrupts:		Contains the interrupt information for the mailbox
			device. The format is dependent on which interrupt
			controller the SoCs use.

Optional Properties:
--------------------
- hi6220,mbox-tx-noirq: Property of MCU firmware's feature, so mailbox driver
			use this flag to ask MCU to enable "automatic idle
			flag" mode or IRQ generated mode to acknowledge a TX
			completion.

Example:
--------

	mailbox: mailbox@f7510000 {
		compatible = "hisilicon,hi6220-mbox";
		reg = <0x0 0xf7510000 0x0 0x1000>, /* IPC_S */
		      <0x0 0x06dff800 0x0 0x0800>; /* Mailbox */
		interrupt-parent = <&gic>;
		interrupts = <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>;
		#mbox-cells = <3>;
	};


Mailbox client
===============

Required properties:
--------------------
- compatible:		Many (See the client docs).
- mboxes:		Standard property to specify a Mailbox (See ./mailbox.txt)
			Cells must match 'mbox-cells' (See Mailbox Device Node above).

Optional Properties:
--------------------
- mbox-names:		Name given to channels seen in the 'mboxes' property.

Example:
--------

	stub_clock: stub_clock {
		compatible = "hisilicon,hi6220-stub-clk";
		hisilicon,hi6220-clk-sram = <&sram>;
		#clock-cells = <1>;
		mbox-names = "mbox-tx", "mbox-rx";
		mboxes = <&mailbox 1 0 11>, <&mailbox 0 1 10>;
	};