[PATCH v6 2/4] dt-bindings: riscv: Add Svade and Svadu Entries

[Yong-Xuan Wang <yongxuan.wang@sifive.com>]

Add entries for the Svade and Svadu extensions to the riscv,isa-extensions
property.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
---
 .../devicetree/bindings/riscv/extensions.yaml | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index 468c646247aa..c3d053ce7783 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -153,6 +153,34 @@ properties:
             ratified at commit 3f9ed34 ("Add ability to manually trigger
             workflow. (#2)") of riscv-time-compare.
 
+        - const: svade
+          description: |
+            The standard Svade supervisor-level extension for SW-managed PTE A/D
+            bit updates as ratified in the 20240213 version of the privileged
+            ISA specification.
+
+            Both Svade and Svadu extensions control the hardware behavior when
+            the PTE A/D bits need to be set. The default behavior for the four
+            possible combinations of these extensions in the device tree are:
+            1) Neither Svade nor Svadu present in DT => It is technically
+               unknown whether the platform uses Svade or Svadu. Supervisor may
+               assume Svade to be present and enabled or it can discover based
+               on mvendorid, marchid, and mimpid.
+            2) Only Svade present in DT => Supervisor must assume Svade to be
+               always enabled. (Obvious)
+            3) Only Svadu present in DT => Supervisor must assume Svadu to be
+               always enabled. (Obvious)
+            4) Both Svade and Svadu present in DT => Supervisor must assume
+               Svadu turned-off at boot time. To use Svadu, supervisor must
+               explicitly enable it using the SBI FWFT extension.
+
+        - const: svadu
+          description: |
+            The standard Svadu supervisor-level extension for hardware updating
+            of PTE A/D bits as ratified at commit c1abccf ("Merge pull request
+            #25 from ved-rivos/ratified") of riscv-svadu. Please refer to Svade
+            dt-binding description for more details.
+
         - const: svinval
           description:
             The standard Svinval supervisor-level extension for fine-grained
-- 
2.17.1