[PATCH v1 2/5] dt-bindings: mailbox: add binding for Microchip IPC mailbox driver
Samuel Holland
samuel.holland at sifive.com
Thu Sep 12 14:23:44 PDT 2024
Hi Valentina,
On 2024-09-12 12:00 PM, Valentina Fernandez wrote:
> Add a dt-binding for the Microchip Inter-Processor Communication (IPC)
> mailbox controller.
>
> Signed-off-by: Valentina Fernandez <valentina.fernandezalanis at microchip.com>
> ---
> .../bindings/mailbox/microchip,sbi-ipc.yaml | 115 ++++++++++++++++++
> 1 file changed, 115 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..dc2cbd5eb28f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml
> @@ -0,0 +1,115 @@
> +# 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 <valentina.fernandezalanis at microchip.com>
> +
> +description:
> + The Microchip Inter-processor Communication (IPC) facilitates
> + message passing between processors using an interrupt signaling
> + mechanism.
> + This SBI interface is compatible with the Mi-V Inter-hart
> + Communication (IHC) IP.
> + The microchip,sbi-ipc compatible string is inteded for use by software
> + running in supervisor privileged mode (s-mode). The SoC-specific
> + compatibles are inteded for use by the SBI implementation in machine
> + mode (m-mode).
There is a lot of conditional logic in this binding for how small it is. Would
it make sense to split this into two separate bindings? For example, with the
current binding microchip,ihc-chan-disabled-mask is allowed for the SBI
interface, but doesn't look like it belongs there.
> +
> +properties:
> + compatible:
> + enum:
> + - microchip,sbi-ipc
> + - microchip,miv-ihc-rtl-v2
> +
> + reg:
> + maxItems: 1
> +
> + interrupts:
> + minItems: 1
> + maxItems: 5
> +
> + interrupt-names:
> + minItems: 1
> + maxItems: 5
> +
> + "#mbox-cells":
> + description:
> + For the SBI "device", the cell represents the global "logical" channel IDs.
> + The meaning of channel IDs are platform firmware dependent. The
> + SoC-specific compatibles are intended for use by the SBI implementation,
> + rather than s-mode software. There the cell would represent the physical
> + channel and do not vary depending on 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. The mask is a 16-bit value, but only
> + the first 15 bits are utilized.Each of the bits corresponds to
> + one of the 15 IHC channels.
> + 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 remaining bit of the 16-bit mask is reserved and should be ignored.
> + The actual enable/disable state of each channel is determined by the
> + IP block’s configuration.
> + $ref: /schemas/types.yaml#/definitions/uint16
> + default: 0
> +
> +required:
> + - compatible
> + - interrupts
> + - interrupt-names
> + - "#mbox-cells"
> +
> +additionalProperties: false
> +
> +allOf:
> + - if:
> + properties:
> + compatible:
> + contains:
> + const: microchip,sbi-ipc
> + then:
> + properties:
> + reg: false
> + else:
> + required:
> + - reg
> +
> + - if:
> + properties:
> + compatible:
> + contains:
> + const: microchip,miv-ihc-rtl-v2
> + then:
> + properties:
> + interrupt-names:
> + items:
> + pattern: "^hart-[0-5]+$"
The driver in patch 3 uses this pattern for the SBI interface, so should it
apply there as well?
Regards,
Samuel
> +
> +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 at 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>;
> + };
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