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[RFC,v2,02/17] dt-bindings: mailbox: Add bindings for RPMI shared memory transport

Message ID 20250203084906.681418-3-apatel@ventanamicro.com (mailing list archive)
State New
Headers show
Series Linux SBI MPXY and RPMI drivers | expand

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Commit Message

Anup Patel Feb. 3, 2025, 8:48 a.m. UTC 
Add device tree bindings for the common RISC-V Platform Management
Interface (RPMI) shared memory transport as a mailbox controller.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 .../mailbox/riscv,rpmi-shmem-mbox.yaml        | 150 ++++++++++++++++++
 1 file changed, 150 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml

Comments

Rob Herring (Arm) Feb. 3, 2025, 10:30 p.m. UTC | #1 
On Mon, Feb 03, 2025 at 02:18:51PM +0530, Anup Patel wrote:
> Add device tree bindings for the common RISC-V Platform Management
> Interface (RPMI) shared memory transport as a mailbox controller.
> 
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
>  .../mailbox/riscv,rpmi-shmem-mbox.yaml        | 150 ++++++++++++++++++
>  1 file changed, 150 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml b/Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml
> new file mode 100644
> index 000000000000..c339df5d9e24
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml
> @@ -0,0 +1,150 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mailbox/riscv,rpmi-shmem-mbox.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: RISC-V Platform Management Interface (RPMI) shared memory mailbox
> +
> +maintainers:
> +  - Anup Patel <anup@brainfault.org>
> +
> +description: |
> +  The RISC-V Platform Management Interface (RPMI) [1] defines a common shared
> +  memory based RPMI transport. This RPMI shared memory transport integrates as
> +  mailbox controller in the SBI implementation or supervisor software whereas
> +  each RPMI service group is mailbox client in the SBI implementation and
> +  supervisor software.
> +
> +  ===========================================
> +  References
> +  ===========================================
> +
> +  [1] RISC-V Platform Management Interface (RPMI)
> +      https://github.com/riscv-non-isa/riscv-rpmi/releases
> +
> +properties:
> +  compatible:
> +    const: riscv,rpmi-shmem-mbox
> +
> +  reg:
> +    oneOf:
> +      - items:
> +          - description: A2P request queue base address
> +          - description: P2A acknowledgment queue base address
> +          - description: P2A request queue base address
> +          - description: A2P acknowledgment queue base address
> +          - description: A2P doorbell address
> +      - items:
> +          - description: A2P request queue base address
> +          - description: P2A acknowledgment queue base address
> +          - description: P2A request queue base address
> +          - description: A2P acknowledgment queue base address
> +      - items:
> +          - description: A2P request queue base address
> +          - description: P2A acknowledgment queue base address
> +          - description: A2P doorbell address
> +      - items:
> +          - description: A2P request queue base address
> +          - description: P2A acknowledgment queue base address
> +
> +  reg-names:
> +    oneOf:
> +      - items:
> +          - const: a2p-req
> +          - const: p2a-ack
> +          - const: p2a-req
> +          - const: a2p-ack
> +          - const: doorbell
> +      - items:
> +          - const: a2p-req
> +          - const: p2a-ack
> +          - const: p2a-req
> +          - const: a2p-ack

These first 2 items lists can be combined with the addition of 
'minItems: 4'

> +      - items:
> +          - const: a2p-req
> +          - const: p2a-ack
> +          - const: doorbell
> +      - items:
> +          - const: a2p-req
> +          - const: p2a-ack
> +
> +  interrupts:
> +    maxItems: 1
> +    description:
> +      The RPMI shared memory transport supports wired interrupt specified by
> +      this property as the P2A doorbell.
> +
> +  msi-parent:
> +    description:
> +      The RPMI shared memory transport supports MSI as P2A doorbell and this
> +      property specifies the target MSI controller.
> +
> +  riscv,slot-size:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    minimum: 64
> +    description:
> +      Power-of-2 RPMI slot size of the RPMI shared memory transport.
> +
> +  riscv,doorbell-mask:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    default: 0xffffffff
> +    description:
> +      Update only the register bits of doorbell defined by the mask (32 bit).
> +
> +  riscv,doorbell-value:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    default: 0x1
> +    description:
> +      Value written to the doorbell register bits (32-bit access) specified
> +      by the riscv,db-mask property.

You mean riscv,doorbell-mask?

I'm confused why you would need both? If the value to write is fixed 
here, then why do you need a mask? You could just mask the value here.

I assume there's some dependency between these 2 properties. That needs 
to be captured with 'dependencies'.

> +
> +  "#mbox-cells":
> +    const: 1
> +    description:
> +      The first cell specifies RPMI service group ID.
> +
> +required:
> +  - compatible
> +  - reg
> +  - reg-names
> +  - riscv,slot-size
> +  - "#mbox-cells"
> +
> +anyOf:
> +  - required:
> +      - interrupts
> +  - required:
> +      - msi-parent
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    // Example 1 (RPMI shared memory with only 2 queues):
> +    mailbox@10080000 {
> +        compatible = "riscv,rpmi-shmem-mbox";
> +        reg = <0x10080000 0x10000>,
> +              <0x10090000 0x10000>,
> +              <0x100a0000 0x4>;
> +        reg-names = "a2p-req", "p2a-ack", "doorbell";
> +        msi-parent = <&imsic_mlevel>;
> +        riscv,slot-size = <64>;
> +        #mbox-cells = <1>;
> +    };
> +  - |
> +    // Example 2 (RPMI shared memory with only 4 queues):
> +    mailbox@10001000 {
> +        compatible = "riscv,rpmi-shmem-mbox";
> +        reg = <0x10001000 0x800>,
> +              <0x10001800 0x800>,
> +              <0x10002000 0x800>,
> +              <0x10002800 0x800>,
> +              <0x10003000 0x4>;
> +        reg-names = "a2p-req", "p2a-ack", "p2a-req", "a2p-ack", "doorbell";
> +        msi-parent = <&imsic_mlevel>;
> +        riscv,slot-size = <64>;
> +        riscv,doorbell-mask = <0x00008000>;
> +        riscv,doorbell-value = <0x00008000>;
> +        #mbox-cells = <1>;
> +    };
> -- 
> 2.43.0
>
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml b/Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml
new file mode 100644
index 000000000000..c339df5d9e24
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml
@@ -0,0 +1,150 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/riscv,rpmi-shmem-mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V Platform Management Interface (RPMI) shared memory mailbox
+
+maintainers:
+  - Anup Patel <anup@brainfault.org>
+
+description: |
+  The RISC-V Platform Management Interface (RPMI) [1] defines a common shared
+  memory based RPMI transport. This RPMI shared memory transport integrates as
+  mailbox controller in the SBI implementation or supervisor software whereas
+  each RPMI service group is mailbox client in the SBI implementation and
+  supervisor software.
+
+  ===========================================
+  References
+  ===========================================
+
+  [1] RISC-V Platform Management Interface (RPMI)
+      https://github.com/riscv-non-isa/riscv-rpmi/releases
+
+properties:
+  compatible:
+    const: riscv,rpmi-shmem-mbox
+
+  reg:
+    oneOf:
+      - items:
+          - description: A2P request queue base address
+          - description: P2A acknowledgment queue base address
+          - description: P2A request queue base address
+          - description: A2P acknowledgment queue base address
+          - description: A2P doorbell address
+      - items:
+          - description: A2P request queue base address
+          - description: P2A acknowledgment queue base address
+          - description: P2A request queue base address
+          - description: A2P acknowledgment queue base address
+      - items:
+          - description: A2P request queue base address
+          - description: P2A acknowledgment queue base address
+          - description: A2P doorbell address
+      - items:
+          - description: A2P request queue base address
+          - description: P2A acknowledgment queue base address
+
+  reg-names:
+    oneOf:
+      - items:
+          - const: a2p-req
+          - const: p2a-ack
+          - const: p2a-req
+          - const: a2p-ack
+          - const: doorbell
+      - items:
+          - const: a2p-req
+          - const: p2a-ack
+          - const: p2a-req
+          - const: a2p-ack
+      - items:
+          - const: a2p-req
+          - const: p2a-ack
+          - const: doorbell
+      - items:
+          - const: a2p-req
+          - const: p2a-ack
+
+  interrupts:
+    maxItems: 1
+    description:
+      The RPMI shared memory transport supports wired interrupt specified by
+      this property as the P2A doorbell.
+
+  msi-parent:
+    description:
+      The RPMI shared memory transport supports MSI as P2A doorbell and this
+      property specifies the target MSI controller.
+
+  riscv,slot-size:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 64
+    description:
+      Power-of-2 RPMI slot size of the RPMI shared memory transport.
+
+  riscv,doorbell-mask:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    default: 0xffffffff
+    description:
+      Update only the register bits of doorbell defined by the mask (32 bit).
+
+  riscv,doorbell-value:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    default: 0x1
+    description:
+      Value written to the doorbell register bits (32-bit access) specified
+      by the riscv,db-mask property.
+
+  "#mbox-cells":
+    const: 1
+    description:
+      The first cell specifies RPMI service group ID.
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - riscv,slot-size
+  - "#mbox-cells"
+
+anyOf:
+  - required:
+      - interrupts
+  - required:
+      - msi-parent
+
+additionalProperties: false
+
+examples:
+  - |
+    // Example 1 (RPMI shared memory with only 2 queues):
+    mailbox@10080000 {
+        compatible = "riscv,rpmi-shmem-mbox";
+        reg = <0x10080000 0x10000>,
+              <0x10090000 0x10000>,
+              <0x100a0000 0x4>;
+        reg-names = "a2p-req", "p2a-ack", "doorbell";
+        msi-parent = <&imsic_mlevel>;
+        riscv,slot-size = <64>;
+        #mbox-cells = <1>;
+    };
+  - |
+    // Example 2 (RPMI shared memory with only 4 queues):
+    mailbox@10001000 {
+        compatible = "riscv,rpmi-shmem-mbox";
+        reg = <0x10001000 0x800>,
+              <0x10001800 0x800>,
+              <0x10002000 0x800>,
+              <0x10002800 0x800>,
+              <0x10003000 0x4>;
+        reg-names = "a2p-req", "p2a-ack", "p2a-req", "a2p-ack", "doorbell";
+        msi-parent = <&imsic_mlevel>;
+        riscv,slot-size = <64>;
+        riscv,doorbell-mask = <0x00008000>;
+        riscv,doorbell-value = <0x00008000>;
+        #mbox-cells = <1>;
+    };