dt-bindings: riscv: add Counter delegation ISA extensions description

Add description for the Smcdeleg/Ssccfg extension.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260807-counter_delegation-v9-10-58658104e487@meta.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>

Documentation/devicetree/bindings/riscv/extensions.yaml

@@ -181,6 +181,13 @@ properties:
             changes to interrupts as frozen at commit ccbddab ("Merge pull
             request #42 from riscv/jhauser-2023-RC4") of riscv-aia.
 
+        - const: smcdeleg
+          description: |
+            The standard Smcdeleg machine-level extension for the machine mode
+            to delegate the hpmcounters to supervisor mode so that they are
+            directly accessible in the supervisor mode as ratified in the
+            20240213 version of the privileged ISA specification.
+
         - const: smcntrpmf
           description: |
             The standard Smcntrpmf machine-level extension for the machine mode
@@ -220,6 +227,14 @@ properties:
             behavioural changes to interrupts as frozen at commit ccbddab
             ("Merge pull request #42 from riscv/jhauser-2023-RC4") of riscv-aia.
 
+        - const: ssccfg
+          description: |
+            The standard Ssccfg supervisor-level extension for configuring
+            the delegated hpmcounters to be accessible directly in supervisor
+            mode as ratified in the 20240213 version of the privileged ISA
+            specification. This extension depends on Sscsrind, Smcdeleg, Zihpm,
+            Zicntr extensions.
+
         - const: ssccptr
           description: |
             The standard Ssccptr extension for main memory (cacheability and
@@ -1135,6 +1150,32 @@ properties:
             allOf:
               - const: zilsd
               - const: zca
+      # Smcdeleg depends on Sscsrind, Zihpm, Zicntr
+      - if:
+          contains:
+            const: smcdeleg
+        then:
+          allOf:
+            - contains:
+                const: sscsrind
+            - contains:
+                const: zihpm
+            - contains:
+                const: zicntr
+      # Ssccfg depends on Smcdeleg, Sscsrind, Zihpm, Zicntr
+      - if:
+          contains:
+            const: ssccfg
+        then:
+          allOf:
+            - contains:
+                const: smcdeleg
+            - contains:
+                const: sscsrind
+            - contains:
+                const: zihpm
+            - contains:
+                const: zicntr
 
 allOf:
   # Zcf extension does not exist on rv64