[PATCH v2 4/9] dt-binding: riscv: add T-HEAD CPU reset

[Jisheng Zhang <jszhang@kernel.org>]

The secondary CPUs in T-HEAD SMP capable platforms need some special
handling. The first one is to write the warm reset entry to entry
register. The second one is write a SoC specific control value to
a SoC specific control reg. The last one is to clone some CSRs for
secondary CPUs to ensure these CSRs' values are the same as the
main boot CPU. This DT node is mainly used by opensbi firmware.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 .../bindings/riscv/thead,cpu-reset.yaml       | 69 +++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/riscv/thead,cpu-reset.yaml

diff --git a/Documentation/devicetree/bindings/riscv/thead,cpu-reset.yaml b/Documentation/devicetree/bindings/riscv/thead,cpu-reset.yaml
new file mode 100644
index 000000000000..ba8c87583b6b
--- /dev/null
+++ b/Documentation/devicetree/bindings/riscv/thead,cpu-reset.yaml
@@ -0,0 +1,69 @@
+# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/riscv/thead,cpu-reset.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-HEAD cpu reset controller
+
+maintainers:
+  - Jisheng Zhang <jszhang@kernel.org>
+
+description: |
+  The secondary CPUs in T-HEAD SMP capable platforms need some special
+  handling. The first one is to write the warm reset entry to entry
+  register. The second one is write a SoC specific control value to
+  a SoC specific control reg. The last one is to clone some CSRs for
+  secondary CPUs to ensure these CSRs' values are the same as the
+  main boot CPU.
+
+properties:
+  $nodename:
+    pattern: "^cpurst"
+
+  compatible:
+    oneOf:
+      - description: CPU reset on T-HEAD TH1520 SoC
+        items:
+          - const: thead,reset-th1520
+
+  entry-reg:
+    $ref: /schemas/types.yaml#/definitions/uint64
+    description: |
+      The entry reg address.
+
+  entry-cnt:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      The entry reg count.
+
+  control-reg:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      The control reg address.
+
+  control-val:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      The value to be set into the control reg.
+
+  csr-copy:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description: |
+      The CSR registers to be cloned during CPU warm reset.
+
+required:
+  - compatible
+
+additionalProperties: false
+
+examples:
+  - |
+    cpurst: cpurst@ffff019050 {
+      compatible = "thead,reset-th1520";
+      entry-reg = <0xff 0xff019050>;
+      entry-cnt = <4>;
+      control-reg = <0xff 0xff015004>;
+      control-val = <0x1c>;
+      csr-copy = <0x7f3 0x7c0 0x7c1 0x7c2 0x7c3 0x7c5 0x7cc>;
+    };
-- 
2.40.0