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

[Anson Huang <anson.huang@nxp.com>]

Hi, Viresh

Best Regards!
Anson Huang

> -----Original Message-----
> From: Viresh Kumar [mailto:viresh.kumar@linaro.org]
> Sent: 2019年2月13日 15:09
> To: Anson Huang <anson.huang@nxp.com>
> Cc: robh+dt@kernel.org; mark.rutland@arm.com; shawnguo@kernel.org;
> s.hauer@pengutronix.de; kernel@pengutronix.de; festevam@gmail.com;
> catalin.marinas@arm.com; will.deacon@arm.com; rjw@rjwysocki.net;
> Aisheng Dong <aisheng.dong@nxp.com>; Daniel Baluta
> <daniel.baluta@nxp.com>; Andy Gross <andy.gross@linaro.org>;
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> 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@nxp.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