[NXP ELE-MUAP 1/7] doc: device tree binding addition for ele MU

[Pankaj Gupta <pankaj.gupta@nxp.com>]

Documentation update with addition of new device tree
for NXP ele-mu (Edgelock Enclave Message Unit), driver.

Signed-off-by: Pankaj Gupta <pankaj.gupta@nxp.com>
---
 .../bindings/arm/freescale/fsl,ele_mu.yaml    | 90 +++++++++++++++++++
 .../devicetree/bindings/mailbox/fsl,muap.txt  | 89 ++++++++++++++++++
 2 files changed, 179 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/freescale/fsl,ele_mu.yaml
 create mode 100644 Documentation/devicetree/bindings/mailbox/fsl,muap.txt

diff --git a/Documentation/devicetree/bindings/arm/freescale/fsl,ele_mu.yaml b/Documentation/devicetree/bindings/arm/freescale/fsl,ele_mu.yaml
new file mode 100644
index 000000000000..8f75a43aec26
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/freescale/fsl,ele_mu.yaml
@@ -0,0 +1,90 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/freescale/fsl,ele_mu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP i.MX EdgeLock Enclave MUAP driver
+
+maintainers:
+  - Pankaj Gupta <pankaj.gupta@nxp.com>
+
+description: |
+  Create char devices in /dev as channels of the form /dev/ele_muXchY with X
+  the id of the driver and Y for each users. It allows to send and receive
+  messages to the NXP EdgeLock Enclave IP on NXP SoC, where current possible
+  value, i.e., supported SoC(s) are imx8ulp, imx93.
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx-ele
+      - fsl,imx93-ele
+
+  mboxes:
+    description:
+      List of <&phandle type channel> - 4 channels for TX, 4 channels for RX,
+      1 channel for TXDB (see mailbox/fsl,muap.txt)
+    maxItems: 9
+
+  mbox-names:
+    items:
+      - const: tx
+      - const: rx
+
+  fsl,ele_mu_did:
+    description:
+      Owner of message-unit, is identified via Domain ID or did.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - enum: [0, 1, 2, 3, 4, 5, 6, 7]
+
+  fsl,ele_mu_id:
+    description:
+      Identifier to the message-unit among the multiple message-unit that exists on SoC.
+      It is used to create the channels, default to 2
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - enum: [0, 1, 2, 3]
+
+  fsl,ele_max_users:
+    description:
+      Number of misclleneous devices to be created, default to 4
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - enum: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+  fsl,cmd_tag:
+    description:
+      Tag in message header for commands on this MU, default to 0x17
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint8
+      - enum: [0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e]
+
+  fsl,rsp_tag:
+    description:
+      Tag in message header for responses on this MU, default to 0xe1
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint8
+      - enum: [0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8]
+
+required:
+  - compatible
+  - mboxes
+  - mbox-names
+
+additionalProperties: false
+
+examples:
+  - |
+    ele_mu: ele_mu {
+      compatible = "fsl,imx93-ele";
+      mbox-names = "tx", "rx";
+      mboxes = <&s4muap 2 0
+          &s4muap 3 0>;
+
+      fsl,ele_mu_id = <1>;
+      fsl,ele_max_users = <4>;
+      fsl,cmd_tag = /bits/ 8 <0x17>;
+      fsl,rsp_tag = /bits/ 8 <0xe1>;
+    };
diff --git a/Documentation/devicetree/bindings/mailbox/fsl,muap.txt b/Documentation/devicetree/bindings/mailbox/fsl,muap.txt
new file mode 100644
index 000000000000..6854ce3467fe
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/fsl,muap.txt
@@ -0,0 +1,89 @@
+NXP i.MX EdgeLock Enclave Message Unit Driver
+=================================================
+
+The Messaging Unit module enables two processing elements within the SoC to
+communicate and coordinate by passing messages (e.g., data, status and control)
+through its interfaces.
+
+The NXP i.MX EdgeLock Enclave Message Unit (ELE-MUAP) is specifically targeted
+for use between application core and Edgelocke Enclave. It allows to send
+messages to the EL Enclave using a shared mailbox.
+ 
+The messages must follow the protocol defined.
+ 
+                                     Non-Secure           +   Secure
+                                                          |
+                                                          |
+                   +---------+      +-------------+       |
+                   | ele_mu.c+<---->+imx-mailbox.c|       |
+                   |         |      |  mailbox.c  +<-->+------+    +------+
+                   +---+-----+      +-------------+    | MU X +<-->+ ELE |
+                       |                               +------+    +------+
+                       +----------------+                 |
+                       |                |                 |
+                       v                v                 |
+                   logical           logical              |
+                   receiver          waiter               |
+                      +                 +                 |
+                      |                 |                 |
+                      |                 |                 |
+                      |            +----+------+          |
+                      |            |           |          |
+                      |            |           |          |
+               device_ctx     device_ctx     device_ctx   |
+                                                          |
+                 User 0        User 1       User Y        |
+                 +------+      +------+     +------+      |
+                 |misc.c|      |misc.c|     |misc.c|      |
+ kernel space    +------+      +------+     +------+      |
+                                                          |
+  +------------------------------------------------------ |
+                     |             |           |          |
+ userspace      /dev/ele_muXch0    |           |          |
+                           /dev/ele_muXch1     |          |
+                                         /dev/ele_muXchY  |
+                                                          |
+
+ When a user sends a command to the ELE, it registers its device_ctx as
+ waiter of a response from ELE.
+ 
+ A user can be registered as receiver of command from the ELE.
+
+ When a message is received, the driver select the device_ctx receiving the
+ message depending on the tag in the message. It selects the device_ctx
+ accordingly.
+
+
+NXP i.MX ELE-MU Device Node:
+===========================
+Required properties:
+--------------------
+- compatible:		Shall be: "fsl,imx-ele", "fsl,imx93-ele"
+- mbox-names:		Contains the name of TX/RX channels- "tx", "rx";
+- mboxes:		Details of the shared mailbox node instance from the
+			device tree. Example values are:
+			For TX: s4muap 0 0
+			For RX: s4muap 1 0
+
+- fsl,ele_mu_id		Contains the message unit id that connects between
+			application core and NXP EL-Enclave.
+- fsl,ele_max_users	For 1 user-space application, value of >2  is suggested. 
+- fsl,cmd_tag		Default value of command tag is 0x17. Though it can be 
+			over-ridden for futures SoCs.
+- fsl,rsp_tag		Default value of command tag is 0xe1. Though it can be 
+			over-ridden for futures SoCs.
+
+Example:
+--------
+
+	ele_mu: ele_mu {
+		compatible = "fsl,imx93-ele";
+		mbox-names = "tx", "rx";
+		mboxes = <&s4muap 2 0
+			&s4muap 3 0>;
+
+		fsl,ele_mu_id = <1>;
+		fsl,ele_max_users = <4>;
+		fsl,cmd_tag = /bits/ 8 <0x17>;
+		fsl,rsp_tag = /bits/ 8 <0xe1>;
+	};
-- 
2.34.1