[PATCH v8 3/5] dt-bindings: remoteproc: Add compatibility for TEE support

[Arnaud Pouliquen]

The "st,stm32mp1-m4-tee" compatible is utilized in a system configuration
where the Cortex-M4 firmware is loaded by the Trusted Execution Environment
(TEE).

For instance, this compatible is used in both the Linux and OP-TEE device
trees:
- In OP-TEE, a node is defined in the device tree with the
  "st,stm32mp1-m4-tee" compatible to support signed remoteproc firmware.
  Based on DT properties, the OP-TEE remoteproc framework is initiated to
  expose a trusted application service to authenticate and load the remote
  processor firmware provided by the Linux remoteproc framework, as well
  as to start and stop the remote processor.
- In Linux, when the compatibility is set, the Cortex-M resets should not
  be declared in the device tree. In such a configuration, the reset is
  managed by the OP-TEE remoteproc driver and is no longer accessible from
  the Linux kernel.

Associated with this new compatible, add the "st,proc-id" property to
identify the remote processor. This ID is used to define a unique ID,
common between Linux, U-Boot, and OP-TEE, to identify a coprocessor.
This ID will be used in requests to the OP-TEE remoteproc Trusted
Application to specify the remote processor.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen at foss.st.com>
Reviewed-by: Rob Herring (Arm) <robh at kernel.org>
---
 .../bindings/remoteproc/st,stm32-rproc.yaml   | 58 ++++++++++++++++---
 1 file changed, 50 insertions(+), 8 deletions(-)

diff --git a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
index 370af61d8f28..409123cd4667 100644
--- a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
+++ b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml
@@ -16,7 +16,12 @@ maintainers:
 
 properties:
   compatible:
-    const: st,stm32mp1-m4
+    enum:
+      - st,stm32mp1-m4
+      - st,stm32mp1-m4-tee
+    description:
+      Use "st,stm32mp1-m4" for the Cortex-M4 coprocessor management by non-secure context
+      Use "st,stm32mp1-m4-tee" for the Cortex-M4 coprocessor management by secure context
 
   reg:
     description:
@@ -43,6 +48,10 @@ properties:
           - description: The offset of the hold boot setting register
           - description: The field mask of the hold boot
 
+  st,proc-id:
+    description: remote processor identifier
+    $ref: /schemas/types.yaml#/definitions/uint32
+
   st,syscfg-tz:
     deprecated: true
     description:
@@ -142,21 +151,43 @@ properties:
 required:
   - compatible
   - reg
-  - resets
 
 allOf:
   - if:
       properties:
-        reset-names:
-          not:
-            contains:
-              const: hold_boot
+        compatible:
+          contains:
+            const: st,stm32mp1-m4
     then:
+      if:
+        properties:
+          reset-names:
+            not:
+              contains:
+                const: hold_boot
+      then:
+        required:
+          - st,syscfg-holdboot
+      else:
+        properties:
+          st,syscfg-holdboot: false
+        required:
+          - reset-names
       required:
-        - st,syscfg-holdboot
-    else:
+        - resets
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: st,stm32mp1-m4-tee
+    then:
       properties:
         st,syscfg-holdboot: false
+        reset-names: false
+        resets: false
+      required:
+        - st,proc-id
 
 additionalProperties: false
 
@@ -188,5 +219,16 @@ examples:
       st,syscfg-rsc-tbl = <&tamp 0x144 0xFFFFFFFF>;
       st,syscfg-m4-state = <&tamp 0x148 0xFFFFFFFF>;
     };
+  - |
+    #include <dt-bindings/reset/stm32mp1-resets.h>
+    m4 at 10000000 {
+      compatible = "st,stm32mp1-m4-tee";
+      reg = <0x10000000 0x40000>,
+            <0x30000000 0x40000>,
+            <0x38000000 0x10000>;
+      st,proc-id = <0>;
+      st,syscfg-rsc-tbl = <&tamp 0x144 0xFFFFFFFF>;
+      st,syscfg-m4-state = <&tamp 0x148 0xFFFFFFFF>;
+    };
 
 ...
-- 
2.25.1