Re: [PATCH V2 1/2] dt-bindings: mailbox: Document qcom,tmel-qmp

[Varadarajan Narayanan <quic_varada@quicinc.com>]

On Tue, Dec 31, 2024 at 11:18:59AM +0530, Sricharan R wrote:
> From: Sricharan Ramabadhran <quic_srichara@quicinc.com>
>
> TMEL SS provides different kinds of services like secureboot, remote image
> authentication, key management, crypto, OEM provisioning etc. This patch adds
> support for remote image authentication. Support for rest of the services can
> be added.
>
> The QMP mailbox is the primary means of communication between TMEL SS and other
> subsystem on the SoC. A dedicated pair of inbound and outbound mailboxes is
> implemented for each subsystem/external execution environment which needs to
> communicate with TMEL for security services. The inbound mailboxes are used to
> send IPC requests to TMEL, which are then processed by TMEL firmware and
> accordingly the responses are sent to the requestor via outbound mailboxes.
>
> It is an IPC transport protocol which is light weight and supports a subset of
> API's. It handles link initialization, negotiation, establishment and
> communication across client(APPSS/BTSS/AUDIOSS) and server(TMEL SS).
>
>    -----------------------------------------------       ---------------------------------------------------
>   |                                              |       |                                                 |
>   |                 SOC  CLIENT                  | SOC   |                TMEL  SS                        |

Fix alignment for last character in above line.

>   |                                              | AHB   |                                                 |
>   |     ----------    ---------   ---------      |       | ------    -------     --------    ------------  |
>   |     |        |    |       |   |       |      | WO    | |     | R |     |     |      |    |SERVICES   | |
>   |     | APPS   |<-->| TMEL  |<->|       |------------->| | IN  |-->|     |     | TMEL |    |--------   | |
>   |     |        |    | COM   |   | QMP   |      | RO    | |     | W | QMP |<--->| COM  |<-->| a) ATTEST | |
>   |     |        |    |       |   |       |<-------------| | OUT |<--|     |     |      |    | b) CRYPTO | |
>   |     |        |    |       |   |       |      |       | |     |   |     |     |      |    | .. more   | |
>   |     ---------     ---------   ---------      |       | ------    -------     -------     ------------  |
>   |                                              |       |                                                 |
>    -----------------------------------------------       --------------------------------------------------
>
> This binding describes the component responsible for communication between the
> TMEL server based subsystems (Q6) and the TMEL client (APPSS/BTSS/AUDIOSS),
> used for security services like secure image authentication, enable/disable
> efuses, crypto services. Each client in the   SoC has its own block of message
> RAM and IRQ for communication with the TMEL SS.
>
> Signed-off-by: Sricharan Ramabadhran <quic_srichara@quicinc.com>
> ---
>   [V2]  Added HW description as per comments.
>         Removed the fallback compatible.
>         Fixed naming convention to TME-L in all places.
>         Fixed indendation for example.
>         Removed the 'description' for some items.
>
>  .../bindings/mailbox/qcom,tmel-qmp.yaml       | 65 +++++++++++++++++++
>  1 file changed, 65 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/qcom,tmel-qmp.yaml
>
> diff --git a/Documentation/devicetree/bindings/mailbox/qcom,tmel-qmp.yaml b/Documentation/devicetree/bindings/mailbox/qcom,tmel-qmp.yaml
> new file mode 100644
> index 000000000000..a434359e0a2c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/qcom,tmel-qmp.yaml
> @@ -0,0 +1,65 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mailbox/qcom,tmel-qmp.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm TMEL IPCC channel
> +
> +maintainers:
> +  - Sricharan Ramabadhran <quic_srichara@quicinc.com>
> +
> +description:
> +  TMEL SS provides different kinds of services like secureboot, remote image
> +  authentication, key management, crypto, OEM provisioning etc. This patch adds
> +  support for remote image authentication. Support for rest of the services can
> +  be added.
> +
> +  The QMP mailbox is the primary means of communication between TMEL SS and
> +  other subsystem on the SoC. A dedicated pair of inbound and outbound mailboxes
> +  is implemented for each subsystem/external execution environment which needs to
> +  communicate with TMEL for security services. The inbound mailboxes are used to
> +  send IPC requests to TMEL, which are then processed by TMEL firmware and
> +  accordingly the responses are sent to the requestor via outbound mailboxes.
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - qcom,ipq5424-tmel-qmp
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  mboxes:
> +    maxItems: 1
> +
> +  "#mbox-cells":
> +    const: 2
> +    description:
> +      The first cell is the client-id, and the second cell is the signal-id.
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - mboxes

Should 'mbox-cells' also be a required property? Since tmel_qmp_parse_devicetree -> mbox_request_channel seems to expect it.

-Varada

> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    tmel_qmp: mailbox@32090000 {
> +        compatible = "qcom,ipq5424-tmel-qmp";
> +        reg = <0x32090000 0x2000>;
> +        interrupts = <GIC_SPI 126 IRQ_TYPE_EDGE_RISING>;
> +        mboxes = <&apcs_glb 20>;
> +        #mbox-cells = <2>;
> +    };
> +
> +...
> --
> 2.34.1
>
>