linux-kernel - RE: [PATCH 3/3] cpufreq: imx-sc: add i.mx system controller cpufreq support

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Message-ID: <DB3PR0402MB3916203C35D82A7667DA3A16F5660@DB3PR0402MB3916.eurprd04.prod.outlook.com>
Date:   Wed, 13 Feb 2019 08:46:45 +0000
From:   Anson Huang <anson.huang@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
CC:     "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "catalin.marinas@....com" <catalin.marinas@....com>,
        "will.deacon@....com" <will.deacon@....com>,
        "rjw@...ysocki.net" <rjw@...ysocki.net>,
        Aisheng Dong <aisheng.dong@....com>,
        Daniel Baluta <daniel.baluta@....com>,
        Andy Gross <andy.gross@...aro.org>,
        "horms+renesas@...ge.net.au" <horms+renesas@...ge.net.au>,
        "heiko@...ech.de" <heiko@...ech.de>,
        "arnd@...db.de" <arnd@...db.de>,
        "bjorn.andersson@...aro.org" <bjorn.andersson@...aro.org>,
        "jagan@...rulasolutions.com" <jagan@...rulasolutions.com>,
        "enric.balletbo@...labora.com" <enric.balletbo@...labora.com>,
        "marc.w.gonzalez@...e.fr" <marc.w.gonzalez@...e.fr>,
        "olof@...om.net" <olof@...om.net>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>
Subject: RE: [PATCH 3/3] cpufreq: imx-sc: add i.mx system controller cpufreq
 support

Hi, Viresh

Best Regards!
Anson Huang

> -----Original Message-----
> From: Viresh Kumar [mailto:viresh.kumar@...aro.org]
> Sent: 2019年2月13日 15:09
> To: Anson Huang <anson.huang@....com>
> Cc: robh+dt@...nel.org; mark.rutland@....com; shawnguo@...nel.org;
> s.hauer@...gutronix.de; kernel@...gutronix.de; festevam@...il.com;
> catalin.marinas@....com; will.deacon@....com; rjw@...ysocki.net;
> Aisheng Dong <aisheng.dong@....com>; Daniel Baluta
> <daniel.baluta@....com>; Andy Gross <andy.gross@...aro.org>;
> horms+renesas@...ge.net.au; heiko@...ech.de; arnd@...db.de;
> bjorn.andersson@...aro.org; jagan@...rulasolutions.com;
> enric.balletbo@...labora.com; marc.w.gonzalez@...e.fr; olof@...om.net;
> devicetree@...r.kernel.org; linux-arm-kernel@...ts.infradead.org; linux-
> kernel@...r.kernel.org; linux-pm@...r.kernel.org; dl-linux-imx <linux-
> imx@....com>
> Subject: Re: [PATCH 3/3] cpufreq: imx-sc: add i.mx system controller cpufreq
> support
> 
> On 13-02-19, 03:09, Anson Huang wrote:
> > On NXP's i.MX SoCs with system controller inside, CPU frequency
> > scaling can ONLY be done by system controller firmware, and it can
> > ONLY be requested from secure mode, so Linux cpufreq driver has to
> > call ARM SMC to trap to ARM-Trusted-Firmware to request system
> > controller firmware to do CPU frequency scaling.
> >
> > This patch adds i.MX system controller cpufreq driver support, when
> > doing CPU frequency scaling, cpufreq driver will do ARM SMC call and
> > trap to ARM-Trusted-Firmware, then SIP(silicon provider) service will
> > communicate with system controller for CPU frequenct scaling.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@....com>
> > ---
> >  drivers/cpufreq/Kconfig.arm      |   9 ++
> >  drivers/cpufreq/Makefile         |   1 +
> >  drivers/cpufreq/imx-sc-cpufreq.c | 183
> > +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 193 insertions(+)
> >  create mode 100644 drivers/cpufreq/imx-sc-cpufreq.c
> 
> Why can't you use cpufreq-dt driver like everyone else ?

Just notice that we can overwrite the set_target if using cpufreq-dt, then we still
need a platform cpufreq file to implement arch_set_freq_scale(), I can use it to save
the code of imx system controller cpufreq driver, and BTW, can cpufreq-dt support
multi clusters cpufreq? As i.MX8QM has 2 clusters running with different OPPs.

Thanks,
Anson.

> 
> --
> viresh