On 13-02-19, 08:46, Anson Huang wrote: > Hi, Viresh > > Best Regards! > Anson Huang > > > -----Original Message----- > > From: Viresh Kumar [mailto:[email protected]] > > Sent: 2019年2月13日 15:09 > > To: Anson Huang <[email protected]> > > Cc: [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > Aisheng Dong <[email protected]>; Daniel Baluta > > <[email protected]>; Andy Gross <[email protected]>; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; > > [email protected]; [email protected]; [email protected]; > > [email protected]; [email protected]; linux- > > [email protected]; [email protected]; dl-linux-imx <linux- > > [email protected]> > > 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 <[email protected]> > > > --- > > > 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
