On 13-02-19, 08:46, Anson Huang wrote: > Hi, Viresh > > Best Regards! > Anson Huang > > > -----Original Message----- > > From: Viresh Kumar [mailto:viresh.kumar@xxxxxxxxxx] > > Sent: 2019年2月13日 15:09 > > To: Anson Huang <anson.huang@xxxxxxx> > > Cc: robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx; shawnguo@xxxxxxxxxx; > > s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx; > > catalin.marinas@xxxxxxx; will.deacon@xxxxxxx; rjw@xxxxxxxxxxxxx; > > Aisheng Dong <aisheng.dong@xxxxxxx>; Daniel Baluta > > <daniel.baluta@xxxxxxx>; Andy Gross <andy.gross@xxxxxxxxxx>; > > horms+renesas@xxxxxxxxxxxx; heiko@xxxxxxxxx; arnd@xxxxxxxx; > > bjorn.andersson@xxxxxxxxxx; jagan@xxxxxxxxxxxxxxxxxxxx; > > enric.balletbo@xxxxxxxxxxxxx; marc.w.gonzalez@xxxxxxx; olof@xxxxxxxxx; > > devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux- > > kernel@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx; dl-linux-imx <linux- > > imx@xxxxxxx> > > 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@xxxxxxx> > > > --- > > > 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 Why do you need to implement arch_set_freq_scale() ? It is already defined for arm64 I believe. > 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. Yes, it supports multi-cluster. -- viresh
