[v4,3/4] dt-bindings: mailbox: add binding for Microchip IPC mailbox controller

Commit Message

Valentina Fernandez Nov. 25, 2024, 5:58 p.m. UTC

Add a dt-binding for the Microchip Inter-Processor Communication (IPC)
mailbox controller.

Signed-off-by: Valentina Fernandez <[e-mail]>
---
 .../bindings/mailbox/microchip,sbi-ipc.yaml   | 111 ++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml

Comments

Krzysztof Kozlowski Nov. 26, 2024, 7:04 a.m. UTC | #1

On Mon, Nov 25, 2024 at 05:58:17PM +0000, Valentina Fernandez wrote:
> Add a dt-binding for the Microchip Inter-Processor Communication (IPC)
> mailbox controller.
> 
> Signed-off-by: Valentina Fernandez <[e-mail]>
> ---
>  .../bindings/mailbox/microchip,sbi-ipc.yaml   | 111 ++++++++++++++++++
>  1 file changed, 111 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml b/Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml
> new file mode 100644
> index 000000000000..b69af85ec608
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml
> @@ -0,0 +1,111 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mailbox/microchip,sbi-ipc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip Inter-processor communication (IPC) mailbox controller
> +
> +maintainers:
> +  - Valentina Fernandez <[e-mail]>
> +
> +description:
> +  The Microchip Inter-processor Communication (IPC) facilitates
> +  message passing between processors using an interrupt signaling
> +  mechanism.
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - description:
> +          Intended for use by software running in supervisor privileged
> +          mode (s-mode). This SBI interface is compatible with the Mi-V
> +          Inter-hart Communication (IHC) IP.
> +        const: microchip,sbi-ipc
> +
> +      - description:
> +          Intended for use by the SBI implementation in machine mode
> +          (m-mode), this compatible string is for the MIV_IHC Soft-IP.
> +        const: microchip,miv-ihc-rtl-v2
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    minItems: 1
> +    maxItems: 5
> +
> +  interrupt-names:
> +    minItems: 1
> +    maxItems: 5
> +    items:
> +      pattern: "^hart-[0-5]+$"

Why hart-0 and hart-5555 are allowed? I thought you have only 5
interrupts. List them instead of pattern, five is small enough still.

> +
> +  "#mbox-cells":
> +    description: >
> +      For "microchip,sbi-ipc", the cell represents the global "logical"
> +      channel IDs. The meaning of channel IDs are platform firmware dependent.
> +
> +      For "microchip,miv-ihc-rtl-v2", the cell represents the physical
> +      channel and does not vary based on the platform firmware.
> +    const: 1
> +
> +  microchip,ihc-chan-disabled-mask:
> +    description: >
> +      Represents the enable/disable state of the bi-directional IHC
> +      channels within the MIV-IHC IP configuration.
> +
> +      A bit set to '1' indicates that the corresponding channel is disabled,
> +      and any read or write operations to that channel will return zero.
> +
> +      A bit set to '0' indicates that the corresponding channel is enabled
> +      and will be accessible through its dedicated address range registers.
> +
> +      The actual enable/disable state of each channel is determined by the
> +      IP block’s configuration.
> +    $ref: /schemas/types.yaml#/definitions/uint16
> +    maximum: 0x7fff
> +    default: 0
> +
> +required:
> +  - compatible
> +  - interrupts
> +  - interrupt-names
> +  - "#mbox-cells"
> +
> +additionalProperties: false

This goes after allOf: block

> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: microchip,sbi-ipc
> +    then:
> +      properties:
> +        reg: false

What does this mean in reality? Device does not have IO address space?
Then it is completely different programming model, isn't it?

> +        microchip,ihc-chan-disabled-mask: false
> +    else:
> +      required:
> +        - reg
> +        - microchip,ihc-chan-disabled-mask
> +
> +examples:
> +  - |
> +    mailbox {
> +      compatible = "microchip,sbi-ipc";
> +      interrupt-parent = <&plic>;
> +      interrupts = <180>, <179>, <178>;
> +      interrupt-names = "hart-1", "hart-2", "hart-3";
> +      #mbox-cells = <1>;
> +    };
> +  - |
> +    mailbox@50000000 {
> +      compatible = "microchip,miv-ihc-rtl-v2";
> +      microchip,ihc-chan-disabled-mask = /bits/ 16 <0>;
> +      reg = <0x50000000 0x1C000>;

Lowercase hex.

> +      interrupt-parent = <&plic>;
> +      interrupts = <180>, <179>, <178>;
> +      interrupt-names = "hart-1", "hart-2", "hart-3";
> +      #mbox-cells = <1>;
> +    };
> -- 
> 2.34.1
>

Conor Dooley Nov. 26, 2024, 4:21 p.m. UTC | #2

On Tue, Nov 26, 2024 at 08:04:38AM +0100, Krzysztof Kozlowski wrote:
> On Mon, Nov 25, 2024 at 05:58:17PM +0000, Valentina Fernandez wrote:
> > +properties:
> > +  compatible:
> > +    oneOf:
> > +      - description:
> > +          Intended for use by software running in supervisor privileged
> > +          mode (s-mode). This SBI interface is compatible with the Mi-V
> > +          Inter-hart Communication (IHC) IP.
> > +        const: microchip,sbi-ipc
> > +
> > +      - description:
> > +          Intended for use by the SBI implementation in machine mode
> > +          (m-mode), this compatible string is for the MIV_IHC Soft-IP.
> > +        const: microchip,miv-ihc-rtl-v2

> > +allOf:
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: microchip,sbi-ipc
> > +    then:
> > +      properties:
> > +        reg: false
> 
> What does this mean in reality? Device does not have IO address space?
> Then it is completely different programming model, isn't it?

Ye, different programming models. Two compatibles for the same hardware,
but one represents the m-mode/firmware programming model that has MMIO
access and is the SBI implementation and the other the s-mode/OS
programming model that uses ecalls provided by the SBI implementation.

> > +        microchip,ihc-chan-disabled-mask: false
> > +    else:
> > +      required:
> > +        - reg
> > +        - microchip,ihc-chan-disabled-mask

Patch

diff --git a/Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml b/Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml
new file mode 100644
index 000000000000..b69af85ec608
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml
@@ -0,0 +1,111 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/microchip,sbi-ipc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip Inter-processor communication (IPC) mailbox controller
+
+maintainers:
+  - Valentina Fernandez <[e-mail]>
+
+description:
+  The Microchip Inter-processor Communication (IPC) facilitates
+  message passing between processors using an interrupt signaling
+  mechanism.
+
+properties:
+  compatible:
+    oneOf:
+      - description:
+          Intended for use by software running in supervisor privileged
+          mode (s-mode). This SBI interface is compatible with the Mi-V
+          Inter-hart Communication (IHC) IP.
+        const: microchip,sbi-ipc
+
+      - description:
+          Intended for use by the SBI implementation in machine mode
+          (m-mode), this compatible string is for the MIV_IHC Soft-IP.
+        const: microchip,miv-ihc-rtl-v2
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 1
+    maxItems: 5
+
+  interrupt-names:
+    minItems: 1
+    maxItems: 5
+    items:
+      pattern: "^hart-[0-5]+$"
+
+  "#mbox-cells":
+    description: >
+      For "microchip,sbi-ipc", the cell represents the global "logical"
+      channel IDs. The meaning of channel IDs are platform firmware dependent.
+
+      For "microchip,miv-ihc-rtl-v2", the cell represents the physical
+      channel and does not vary based on the platform firmware.
+    const: 1
+
+  microchip,ihc-chan-disabled-mask:
+    description: >
+      Represents the enable/disable state of the bi-directional IHC
+      channels within the MIV-IHC IP configuration.
+
+      A bit set to '1' indicates that the corresponding channel is disabled,
+      and any read or write operations to that channel will return zero.
+
+      A bit set to '0' indicates that the corresponding channel is enabled
+      and will be accessible through its dedicated address range registers.
+
+      The actual enable/disable state of each channel is determined by the
+      IP block’s configuration.
+    $ref: /schemas/types.yaml#/definitions/uint16
+    maximum: 0x7fff
+    default: 0
+
+required:
+  - compatible
+  - interrupts
+  - interrupt-names
+  - "#mbox-cells"
+
+additionalProperties: false
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: microchip,sbi-ipc
+    then:
+      properties:
+        reg: false
+        microchip,ihc-chan-disabled-mask: false
+    else:
+      required:
+        - reg
+        - microchip,ihc-chan-disabled-mask
+
+examples:
+  - |
+    mailbox {
+      compatible = "microchip,sbi-ipc";
+      interrupt-parent = <&plic>;
+      interrupts = <180>, <179>, <178>;
+      interrupt-names = "hart-1", "hart-2", "hart-3";
+      #mbox-cells = <1>;
+    };
+  - |
+    mailbox@50000000 {
+      compatible = "microchip,miv-ihc-rtl-v2";
+      microchip,ihc-chan-disabled-mask = /bits/ 16 <0>;
+      reg = <0x50000000 0x1C000>;
+      interrupt-parent = <&plic>;
+      interrupts = <180>, <179>, <178>;
+      interrupt-names = "hart-1", "hart-2", "hart-3";
+      #mbox-cells = <1>;
+    };