dt-bindings: riscv: add Zca, Zcf, Zcd and Zcb ISA extension description

Add description for Zca, Zcf, Zcd and Zcb extensions which are part the
Zc* standard extensions for code size reduction. Additional validation
rules are added since Zcb depends on Zca, Zcf, depends on Zca and F, Zcd
depends on Zca and D and finally, Zcf can not be present on rv64.

Signed-off-by: Clément Léger <[email protected]>
Reviewed-by: Conor Dooley <[email protected]>
Reviewed-by: Charlie Jenkins <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

Author: clementleger

Documentation/devicetree/bindings/riscv/extensions.yaml

@@ -220,6 +220,38 @@ properties:
             instructions as ratified at commit 6d33919 ("Merge pull request #158
             from hirooih/clmul-fix-loop-end-condition") of riscv-bitmanip.
 
+        - const: zca
+          description: |
+            The Zca extension part of Zc* standard extensions for code size
+            reduction, as ratified in commit 8be3419c1c0 ("Zcf doesn't exist on
+            RV64 as it contains no instructions") of riscv-code-size-reduction,
+            merged in the riscv-isa-manual by commit dbc79cf28a2 ("Initial seed
+            of zc.adoc to src tree.").
+
+        - const: zcb
+          description: |
+            The Zcb extension part of Zc* standard extensions for code size
+            reduction, as ratified in commit 8be3419c1c0 ("Zcf doesn't exist on
+            RV64 as it contains no instructions") of riscv-code-size-reduction,
+            merged in the riscv-isa-manual by commit dbc79cf28a2 ("Initial seed
+            of zc.adoc to src tree.").
+
+        - const: zcd
+          description: |
+            The Zcd extension part of Zc* standard extensions for code size
+            reduction, as ratified in commit 8be3419c1c0 ("Zcf doesn't exist on
+            RV64 as it contains no instructions") of riscv-code-size-reduction,
+            merged in the riscv-isa-manual by commit dbc79cf28a2 ("Initial seed
+            of zc.adoc to src tree.").
+
+        - const: zcf
+          description: |
+            The Zcf extension part of Zc* standard extensions for code size
+            reduction, as ratified in commit 8be3419c1c0 ("Zcf doesn't exist on
+            RV64 as it contains no instructions") of riscv-code-size-reduction,
+            merged in the riscv-isa-manual by commit dbc79cf28a2 ("Initial seed
+            of zc.adoc to src tree.").
+
         - const: zfa
           description:
             The standard Zfa extension for additional floating point
@@ -519,5 +551,51 @@ properties:
             Registers in the AX45MP datasheet.
             https://www.andestech.com/wp-content/uploads/AX45MP-1C-Rev.-5.0.0-Datasheet.pdf
 
+    allOf:
+      # Zcb depends on Zca
+      - if:
+          contains:
+            const: zcb
+        then:
+          contains:
+            const: zca
+      # Zcd depends on Zca and D
+      - if:
+          contains:
+            const: zcd
+        then:
+          allOf:
+            - contains:
+                const: zca
+            - contains:
+                const: d
+      # Zcf depends on Zca and F
+      - if:
+          contains:
+            const: zcf
+        then:
+          allOf:
+            - contains:
+                const: zca
+            - contains:
+                const: f
+
+allOf:
+  # Zcf extension does not exist on rv64
+  - if:
+      properties:
+        riscv,isa-extensions:
+          contains:
+            const: zcf
+        riscv,isa-base:
+          contains:
+            const: rv64i
+    then:
+      properties:
+        riscv,isa-extensions:
+          not:
+            contains:
+              const: zcf
+
 additionalProperties: true
 ...