[RFC LINUX PATCH] Dcoumentation: dt: mailbox: Add Xilinx IPI Mailbox

[Wendy Liang]

Xilinx ZynqMP IPI(Inter Processor Interrupt) is a hardware block
in ZynqMP SoC used for the communication between various processor
systems.

Signed-off-by: Wendy Liang <jliang@xxxxxxxxxx>
---
 .../bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt   | 88 ++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt

diff --git a/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
new file mode 100644
index 0000000..5d915d1
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
@@ -0,0 +1,88 @@
+Xilinx IPI Mailbox Driver
+========================================
+
+The Xilinx IPI(Inter Processor Interrupt) mailbox driver is a mailbox
+controller that manages the messaging between two IPI agents. Each IPI
+mailbox has request and response buffers between the two IPI agents.
+
++-------------------------------------+
+|                                     |
+| Xilinx ZynqMP IPI Mailbox Controller|
+|                                     |
+|                       +-------------+
+|                       |     SMC     |
+|                       |             |
++--------+--------------+------+------+
+         |                     |
+         |          +-----------------+
+         |                     |   ATF (ARM trusted firmware)
+         |                     |
++-------------------------------------+
+         |                     |   Hardware
+         |                     |
+ +--------------------------------------+
+                               |        |
+ +----------------------+ +-----------+ |
+ | | Buffers between    | | IPI Agent | |
+ | | two IPI agents     | | Registers | |
+ | +--------------------+ +-----------+ |
+ |                                      |
+ |   Xilinx ZynqMP IPI                  |
+ +--------------------------------------+
+
+
+Message Manager Device Node:
+===========================
+Required properties:
+--------------------
+- compatible:		Shall be: "xlnx,zynqmp-ipi-mailbox"
+- ipi-smc-fid-base	Base offset of SMC function IDs for IPI mailbox SMC.
+			It contains the IPI IDs of the two IPI agents.
+- reg:			IPI request and response buffers address range. It
+			can be the IPI buffers from the hardware or it can
+			be carved out shared memory.
+- reg-names:		Reg resource name of the IPI request and response
+			buffers.
+- #mbox-cells:		Shall be 1. Contains the logical channel IDs of the
+			channels on the IPI mailbox.
+- interrupt-parent:	Phandle for the interrupt controller.
+- interrupts:		Interrupt mapping.
+
+Required properties:
+--------------------
+- method:		The method of accessing the IPI agent registers.
+			Permitted values are: "smc" and "hvc". Default is
+			"smc".
+Example:
+------------
+	/* APU IPI mailbox driver */
+	ipis {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		ipi_mailbox_apu_rpu0: ipi_mailbox@0 {
+			compatible = "xlnx,zynqmp-ipi-mailbox";
+			reg = <0 0xff990400 40>;
+			reg-names = "apu-rpu0";
+			ipi-smc-fid-base = <0x1010>;
+			method = "smc";
+			#mbox-cells = <1>;
+			interrupt-parent = <&gic>;
+			interrupts = <0 35 4>;
+		};
+		ipi_mailbox_apu_rpu1: ipi_mailbox@1 {
+			compatible = "xlnx,zynqmp-ipi-mailbox";
+			reg = <0 0xff990440 40>;
+			reg-names = "apu-rpu1";
+			ipi-smc-fid-base = <0x1020>;
+			method = "smc";
+			#mbox-cells = <1>;
+			interrupt-parent = <&gic>;
+			interrupts = <0 35 4>;
+		};
+	};
+	device0: device0 {
+		...
+		mbox-names = "rpu0", "rpu1",
+		mboxes = <&ipi_mailbox_apu_rpu0 0>,
+			 < &ipi_mailbox_apu_rpu1 0>;
+	};
-- 
2.7.4