RE: [PATCH 0/3] Add power domain driver support for i.mx8m family

Jacky Bai
2020-02-13T09:21:21Z

> -----Original Message-----
> From: Schrempf Frieder <frieder.schrempf@kontron.de>
> Sent: Thursday, February 13, 2020 5:16 PM
> To: Adam Ford <aford173@gmail.com>; Sudeep Holla
> <sudeep.holla@arm.com>
> Cc: Aisheng Dong <aisheng.dong@nxp.com>; mark.rutland@arm.com; Peng
> Fan <peng.fan@nxp.com>; Souvik Chakravarty
> <Souvik.Chakravarty@arm.com>; Jacky Bai <ping.bai@nxp.com>;
> devicetree@vger.kernel.org; Clément Faure <clement.faure@nxp.com>;
> s.hauer@pengutronix.de; shawnguo@kernel.org; robh+dt@kernel.org;
> dl-linux-imx <linux-imx@nxp.com>; kernel@pengutronix.de; Andre Przywara
> <andre.przywara@arm.com>; Silvano Di Ninno <silvano.dininno@nxp.com>;
> Leonard Crestez <leonard.crestez@nxp.com>; festevam@gmail.com;
> linux-arm-kernel@lists.infradead.org; Lucas Stach <l.stach@pengutronix.de>
> Subject: Re: [PATCH 0/3] Add power domain driver support for i.mx8m family
>
> Hi,
>
> On 07.11.19 22:28, Adam Ford wrote:
> > On Thu, Apr 18, 2019 at 9:43 AM Sudeep Holla <sudeep.holla@arm.com>
> wrote:
> >>
> >> On Wed, Apr 17, 2019 at 04:21:55PM +0000, Leonard Crestez wrote:
> >>> On 4/17/2019 4:33 PM, Sudeep Holla wrote:
> >>>>>> I don't yet buy the security argument. There are many more shared
> >>>>>> parts on the SoC, like the clock controller, that would need to
> >>>>>> be taken away from the non-secure world if one would want to run
> >>>>>> an untrusted OS kernel on a i.MX8M system.
> >>>>>>
> >>>>>> To properly implement security on any i.MX8M based system the
> >>>>>> firmware would need to grow something like a full ARM SCPI
> >>>>>> implementation, so all shared critical peripherals are solely under
> firmware control.
> >>>>>
> >>>>> It might be possible to rework this to use some form of
> >>>>> SCMI-over-SMC instead of vendor-specific SMCCC SIP calls
> >
> > I was just curious to know if there is any progress being made on
> > this. The i.mx8mm-evk is missing functionality upstream and I think
> > the power domain support would help enable some of these features.
> >
>
> Has there been any decision or action taken in this topic?
> Will the power domain driver as proposed in this patch be upstreamed at
> some time, or rather not?
>
> I try to build a mainline BSP for i.MX8MM (ML U-Boot, ML TF-A, ML Linux)
> and I integrated display and graphics support from the downstream NXP
> kernel.
>
> While most things already work fine, there's the issue of how to handle the
> power domains. Currently I need to ungate some clocks in the TF-A
> BL31 to get for example the GPU running. If I understand this correctly the
> proposed power domain driver could handle this in Linux otherwise.
>

the SCMI over SMC is still under review

BR
Jacky Bai
> Thanks,
> Frieder