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From:   Peng Fan <peng.fan@nxp.com>
To:     Sudeep Holla <sudeep.holla@arm.com>
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        "mark.rutland@arm.com" <mark.rutland@arm.com>,
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        <linux-arm-kernel@lists.infradead.org>,
        dl-linux-imx <linux-imx@nxp.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>
Subject: RE: [PATCH v11 2/2] mailbox: introduce ARM SMC based mailbox
Thread-Topic: [PATCH v11 2/2] mailbox: introduce ARM SMC based mailbox
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Date:   Thu, 5 Dec 2019 03:24:14 +0000
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> Subject: Re: [PATCH v11 2/2] mailbox: introduce ARM SMC based mailbox
>=20
> (+Viresh,Arnd)
>=20
> On Mon, Dec 02, 2019 at 10:14:43AM +0000, Peng Fan wrote:
> > From: Peng Fan <peng.fan@nxp.com>
> >
> > This mailbox driver implements a mailbox which signals transmitted
> > data via an ARM smc (secure monitor call) instruction. The mailbox
> > receiver is implemented in firmware and can synchronously return data
> > when it returns execution to the non-secure world again.
> > An asynchronous receive path is not implemented.
> > This allows the usage of a mailbox to trigger firmware actions on SoCs
> > which either don't have a separate management processor or on which
> > such a core is not available. A user of this mailbox could be the SCP
> > interface.
> >
>=20
> I would like to know all the use-cases for this driver ?=20

Currently my usecase is SCMI.

Is this only for SCMI or
> will this get used with other protocols on the top. I assume the latter a=
nd
> hence it is preferred to keep this as a mailbox driver.
>=20
> I am not against this approach but the reason I ask is to avoid duplicati=
on.
> Viresh has suggested abstraction of transport from SCMI driver to enable
> other transports[1]. Couple of transports that I am aware of is this SMC/=
HVC
> and the new(still in-concept) SPCI.
>=20
> So I am looking for opinions on that approach. Please feel free to commen=
t
> here or as part of that patch.

If we want to use SMC as transports, smc mailbox or smc transports(non-mail=
box)
could be used. Both ok for me, smc transports just need write a new driver
under scmi folder.

I left the decision to you(scmi maintainer) and Jassi(mailbox maintainer),
Just hope the smc/hvc used as transports could be landed in upstream soon.

Thanks,
Peng.

>=20
> --
> Regards,
> Sudeep
>=20
> [1]
> https://eur01.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2Flore.=
ke
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> 19719.git.viresh.kumar%40linaro.org&amp;data=3D02%7C01%7Cpeng.fan%40n
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