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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 21 Jan 2020 16:11:11 +0100
Message-ID: <CAK8P3a0fWf-wd8exJa+_UL9n0bQ26W6wd0iQH32osM1Q+cLu_w@mail.gmail.com>
Subject: Re: [PATCH V3] firmware: arm_scmi: Make scmi core independent of the
 transport type
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Sudeep Holla <sudeep.holla@arm.com>,
        Jassi Brar <jassisinghbrar@gmail.com>,
        cristian.marussi@arm.com, Peng Fan <peng.fan@nxp.com>,
        peter.hilber@opensynergy.com,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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On Tue, Jan 21, 2020 at 9:27 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> The SCMI specification is fairly independent of the transport protocol,
> which can be a simple mailbox (already implemented) or anything else.
> The current Linux implementation however is very much dependent on the
> mailbox transport layer.
>
> This patch makes the SCMI core code (driver.c) independent of the
> mailbox transport layer and moves all mailbox related code to a new
> file: mailbox.c.
>
> We can now implement more transport protocols to transport SCMI
> messages.
>
> The transport protocols just need to provide struct scmi_transport_ops,
> with its version of the callbacks to enable exchange of SCMI messages.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> @Sudeep: Can you please help me getting this tested?
>
> V2->V3:
> - Added more ops to the structure to read/write/memcpy data
> - Payload is moved to mailbox.c and is handled in transport specific way
>   now. This resulted in lots of changes.

This addresses the comments I had about the implementation.

It's still hard for me to judge whether this is a good abstraction as
long as there is only one backend in the framework, but I see nothing
immediately wrong with it either.

       Arnd