dt-bindings: remoteproc: Add HSM M4F core on TI K3 SoCs

Some of the TI K3 family of SoCs have a HSM (High Security Module) M4F
core in the Wakeup Voltage Domain which could be used to run secure
services like Authentication. Add the device tree bindings document for
this HSM M4F core.

The added example illustrates the DT node for the HSM core present on K3
J722S SoC.

Signed-off-by: Beleswar Padhi <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mathieu Poirier <[e-mail]>

Documentation/devicetree/bindings/remoteproc/ti,hsm-m4fss.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/remoteproc/ti,hsm-m4fss.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TI K3 HSM M4F processor subsystems
+
+maintainers:
+  - Beleswar Padhi <[e-mail]>
+
+description: |
+  Some K3 family SoCs have a HSM (High Security Module) M4F core in the
+  Wakeup Voltage Domain which could be used to run secure services like
+  Authentication. Some of those are J721S2, J784S4, J722S, AM62X.
+
+$ref: /schemas/arm/keystone/ti,k3-sci-common.yaml#
+
+properties:
+  compatible:
+    enum:
+      - ti,hsm-m4fss
+
+  reg:
+    items:
+      - description: SRAM0_0 internal memory region
+      - description: SRAM0_1 internal memory region
+      - description: SRAM1 internal memory region
+
+  reg-names:
+    items:
+      - const: sram0_0
+      - const: sram0_1
+      - const: sram1
+
+  resets:
+    maxItems: 1
+
+  firmware-name:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - resets
+  - firmware-name
+  - ti,sci
+  - ti,sci-dev-id
+  - ti,sci-proc-ids
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        remoteproc@43c00000 {
+            compatible = "ti,hsm-m4fss";
+            reg = <0x00 0x43c00000 0x00 0x20000>,
+                  <0x00 0x43c20000 0x00 0x10000>,
+                  <0x00 0x43c30000 0x00 0x10000>;
+            reg-names = "sram0_0", "sram0_1", "sram1";
+            resets = <&k3_reset 225 1>;
+            firmware-name = "hsm.bin";
+            ti,sci = <&sms>;
+            ti,sci-dev-id = <225>;
+            ti,sci-proc-ids = <0x80 0xff>;
+        };
+    };