Re: [PATCH] firmware: arm_scmi: Make scmi core independent of transport type

From: Sudeep Holla <sudeep.holla@arm.com>
To: Jassi Brar <jassisinghbrar@gmail.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] firmware: arm_scmi: Make scmi core independent of transport type
Date: Mon, 6 Jan 2020 11:00:07 +0000	[thread overview]
Message-ID: <20200106110007.GA54466@bogus> (raw)
In-Reply-To: <CABb+yY0qh-qWJWxEaB9_XxmiFb=xP0hOxpm1j54seeT3dMKt2w@mail.gmail.com>

On Tue, Dec 31, 2019 at 02:09:27PM -0600, Jassi Brar wrote:
> On Fri, Nov 29, 2019 at 3:32 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 of 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.
> >
> We can either add new transport layer between SCMI and Mailbox layers,
> or we can write new transport as a mailbox driver (which I always
> thought could be a usecase). Right now I am of no strong opinion
> either way.  Depends, what other transport do you have in mind?
>

To be more clear, this patch abstracts the SCMI transport so that mailbox
can be one of the transport. The plan is to add SMC/HVC, SMC/HVC over SPCI,
vitio based transport as alternative to mailbox. These are neither added
as mailbox driver nor transport layer between SCMI and Mailbox. E.g.:
we either use Peng's SMC based mailbox driver as is or add a new transport
independent of mailbox framework here as SCMI transport.

--
Regards,
Sudeep