[PATCH v3 1/2] dt-bindings: firmware: arm,scmi: Support mailboxes unidirectional channels

[Rob Herring]

On Tue, 04 Apr 2023 12:50:25 +0100, Cristian Marussi wrote:
> SCMI defines two kinds of communication channels between the agent and the
> platform: one bidirectional 'a2p' channel used by the agent to send SCMI
> commands and synchronously receive the related replies, and an optional
> 'p2a' unidirectional channel used to asynchronously receive delayed
> responses and notifications emitted from the platform.
> 
> When configuring an SCMI transport based on mailboxes, the current binding
> supports only mailboxes providing bidirectional channels: in such a case
> one mailbox channel can be easily assigned to each SCMI channel as above
> described.
> 
> In case, instead, to have to deal with mailboxes providing only distinct
> unidirectional channels, it becomes necessary to extend the binding in
> order to be able to bind 2 distinct unidirectional mailbox channels to the
> same SCMI 'a2p' channel.
> 
> Bidirectional and unidirectional channels support for the SCMI mailbox
> transport can coexist by carefully considering the effective combination
> of defined 'mboxes' and 'shmem' descriptors.
> 
> Signed-off-by: Cristian Marussi <cristian.marussi at arm.com>
> ---
> Cc: Rob Herring <robh+dt at kernel.org>
> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt at linaro.org>
> Cc: devicetree at vger.kernel.org
> 
> v2 --> v3
> - coalesced oneOf entries using proper minItems
> - removed unidirectional channels example
> v1 --> v2
> - added mbox-names unidirectional definitions and example
> ---
>  .../bindings/firmware/arm,scmi.yaml           | 48 +++++++++++++++----
>  1 file changed, 38 insertions(+), 10 deletions(-)
> 

Reviewed-by: Rob Herring <robh at kernel.org>