From: Morten Borup Petersen <morten.petersen@xxxxxxx>
This patch adds device tree binding for Message Handling Unit
controller version 2 from Arm.
Signed-off-by: Morten Borup Petersen <morten.petersen@xxxxxxx>
Signed-off-by: Tushar Khandelwal <tushar.khandelwal@xxxxxxx>
Cc: robh+dt@xxxxxxxxxx
Cc: mark.rutland@xxxxxxx
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: jassisinghbrar@xxxxxxxxx
---
.../devicetree/bindings/mailbox/arm,mhuv2.txt | 108 ++++++++++++++++++
1 file changed, 108 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mailbox/arm,mhuv2.txt
diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhuv2.txt b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.txt
new file mode 100644
index 000000000000..3a05593414bc
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.txt
@@ -0,0 +1,108 @@
+Arm MHUv2 Mailbox Driver
+========================
+
+The Arm Message-Handling-Unit (MHU) Version 2 is a mailbox controller that has
+between 1 and 124 channel windows to provide unidirectional communication with
+remote processor(s).
+
+Given the unidirectional nature of the device, an MHUv2 mailbox may only be
+written to or read from. If a pair of MHU devices is implemented between two
+processing elements to provide bidirectional communication, these must be
+specified as two separate mailboxes.
+
+A device tree node for an Arm MHUv2 device must specify either a receiver frame
+or a sender frame, indicating which end of the unidirectional MHU device which
+the device node entry describes.
+
+An MHU device must be specified with a transport protocol. The transport
+protocol of an MHU device determines the method of data transmission as well as
+the number of provided mailboxes.
+Following are the possible transport protocol types:
+- Single-word: An MHU device implements as many mailboxes as it
+ provides channel windows. Data is transmitted through
+ the MHU registers.
+- Multi-word: An MHU device implements a single mailbox. All channel windows
+ will be used during transmission. Data is transmitted through
+ the MHU registers.
+- Doorbell: An MHU device implements as many mailboxes as there are flag
+ bits available in its channel windows. Optionally, data may
+ be transmitted through a shared memory region, wherein the MHU
+ is used strictly as an interrupt generation mechanism.
+
+Mailbox Device Node:
+====================
+
+Required properties:
+--------------------
+- compatible: Shall be "arm,mhuv2" & "arm,primecell"
+- reg: Contains the mailbox register address range (base
+ address and length)
+- #mbox-cells Shall be 1 - the index of the channel needed.
+- mhu-frame Frame type of the device.
+ Shall be either "sender" or "receiver"
+- mhu-protocol Transport protocol of the device. Shall be one of the
+ following: "single-word", "multi-word", "doorbell"
+
+Required properties (receiver frame):
+-------------------------------------
+- interrupts: Contains the interrupt information corresponding to the
+ combined interrupt of the receiver frame
+
+Example:
+--------
+
+ mbox_mw_tx: mhu@10000000 {
+ compatible = "arm,mhuv2","arm,primecell";
+ reg = <0x10000000 0x1000>;
+ clocks = <&refclk100mhz>;
+ clock-names = "apb_pclk";
+ #mbox-cells = <1>;
+ mhu-protocol = "multi-word";
+ mhu-frame = "sender";
+ };
+
+ mbox_sw_tx: mhu@10000000 {
+ compatible = "arm,mhuv2","arm,primecell";
+ reg = <0x11000000 0x1000>;
+ clocks = <&refclk100mhz>;
+ clock-names = "apb_pclk";
+ #mbox-cells = <1>;
+ mhu-protocol = "single-word";
+ mhu-frame = "sender";
+ };
+
+ mbox_db_rx: mhu@10000000 {
+ compatible = "arm,mhuv2","arm,primecell";
+ reg = <0x12000000 0x1000>;
+ clocks = <&refclk100mhz>;
+ clock-names = "apb_pclk";
+ #mbox-cells = <1>;
+ interrupts = <0 45 4>;
+ interrupt-names = "mhu_rx";
+ mhu-protocol = "doorbell";
+ mhu-frame = "receiver";
+ };
+
+ mhu_client: scb@2e000000 {
+ compatible = "fujitsu,mb86s70-scb-1.0";
+ reg = <0 0x2e000000 0x4000>;
+ mboxes =
+ // For multi-word frames, client may only instantiate a single
+ // mailbox for a mailbox controller
+ <&mbox_mw_tx 0>,
+
+ // For single-word frames, client may instantiate as many
+ // mailboxes as there are channel windows in the MHU
+ <&mbox_sw_tx 0>,
+ <&mbox_sw_tx 1>,
+ <&mbox_sw_tx 2>,
+ <&mbox_sw_tx 3>,
+
+ // For doorbell frames, client may instantiate as many mailboxes
+ // as there are bits available in the combined number of channel
+ // windows ((channel windows * 32) mailboxes)
+ <mbox_db_rx 0>,
+ <mbox_db_rx 1>,
+ ...
+ <mbox_db_rx 17>;
+ };
\ No newline at end of file
--
2.17.1
