1 files changed, 43 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/mailbox/arm-mhu.txt b/Documentation/devicetree/bindings/mailbox/arm-mhu.txt
new file mode 100644
index 000000000000..4971f03f0b33
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/arm-mhu.txt
@@ -0,0 +1,43 @@
+ARM MHU Mailbox Driver
+======================
+
+The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has
+3 independent channels/links to communicate with remote processor(s).
+ MHU links are hardwired on a platform. A link raises interrupt for any
+received data. However, there is no specified way of knowing if the sent
+data has been read by the remote. This driver assumes the sender polls
+STAT register and the remote clears it after having read the data.
+The last channel is specified to be a 'Secure' resource, hence can't be
+used by Linux running NS.
+
+Mailbox Device Node:
+====================
+
+Required properties:
+--------------------
+- compatible:           Shall be "arm,mhu" & "arm,primecell"
+- reg:                  Contains the mailbox register address range (base
+                        address and length)
+- #mbox-cells           Shall be 1 - the index of the channel needed.
+- interrupts:           Contains the interrupt information corresponding to
+                        each of the 3 links of MHU.
+
+Example:
+--------
+
+        mhu: mailbox@2b1f0000 {
+                #mbox-cells = <1>;
+                compatible = "arm,mhu", "arm,primecell";
+                reg = <0 0x2b1f0000 0x1000>;
+                interrupts = <0 36 4>, /* LP-NonSecure */
+                             <0 35 4>, /* HP-NonSecure */
+                             <0 37 4>; /* Secure */
+                clocks = <&clock 0 2 1>;
+                clock-names = "apb_pclk";
+        };
+
+        mhu_client: scb@2e000000 {
+                compatible = "fujitsu,mb86s70-scb-1.0";
+                reg = <0 0x2e000000 0x4000>;
+                mboxes = <&mhu 1>; /* HP-NonSecure */
+        };