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

[Sricharan Ramabadhran <quic_srichara@quicinc.com>]

On 12/31/2024 11:27 AM, Varadarajan Narayanan wrote:
> 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.
> 
ok.

>>    |                                              | 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.
ok, will add.

Regards,
  Sricharan