On Fri, 2022-04-15 at 14:24 +0200, AngeloGioacchino Del Regno wrote:
> Il 15/04/22 07:59, Rex-BC Chen ha scritto:
> > From: Jia-Wei Chang <jia-wei.chang@xxxxxxxxxxxx>
> >
> > In some MediaTek SoCs, like MT8183, CPU and CCI share the same
> > power
> > supplies. Cpufreq needs to check if CCI devfreq exists and wait
> > until
> > CCI devfreq ready before scaling frequency.
> >
> > Before CCI devfreq is ready, we record the voltage when booting to
> > kernel and use the max(cpu target voltage, booting voltage) to
> > prevent cpufreq adjust to the lower voltage which will cause the
> > CCI
> > crash because of high frequency and low voltage.
> >
> > - Add is_ccifreq_ready() to link CCI device to CPI, and CPU will
> > start
> > DVFS when CCI is ready.
> > - Add platform data for MT8183.
> >
> > Signed-off-by: Jia-Wei Chang <jia-wei.chang@xxxxxxxxxxxx>
> > Signed-off-by: Rex-BC Chen <rex-bc.chen@xxxxxxxxxxxx>
>
> I am enthusiast to see that the solution that I've proposed was
> welcome!
>
> I only have one nit on this patch, check below:
>
Hello Angelo,
Thanks for your advice for this modification.
I also reply to Kevin and describe this solution.
Let's wait for Kevin's feedback and other suggestion.
> > ---
> > drivers/cpufreq/mediatek-cpufreq.c | 80
> > +++++++++++++++++++++++++++++-
> > 1 file changed, 79 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c
> > b/drivers/cpufreq/mediatek-cpufreq.c
> > index d4c00237e862..dd3f739fede1 100644
> > --- a/drivers/cpufreq/mediatek-cpufreq.c
> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
>
> ..snip..
>
> > @@ -225,6 +251,14 @@ static int mtk_cpufreq_set_target(struct
> > cpufreq_policy *policy,
> > vproc = dev_pm_opp_get_voltage(opp);
> > dev_pm_opp_put(opp);
> >
> > + /*
> > + * If MediaTek cci is supported but is not ready, we will use
> > the value
> > + * of max(target cpu voltage, booting voltage) to prevent high
> > freqeuncy
> > + * low voltage crash.
> > + */
> > + if (info->soc_data->ccifreq_supported &&
> > !is_ccifreq_ready(info))
> > + vproc = max(vproc, info->vproc_on_boot);
> > +
> > /*
> > * If the new voltage or the intermediate voltage is higher
> > than the
> > * current voltage, scale up voltage first.
>
> ..snip..
>
> > @@ -423,6 +484,13 @@ static int mtk_cpu_dvfs_info_init(struct
> > mtk_cpu_dvfs_info *info, int cpu)
> > if (ret)
> > goto out_disable_mux_clock;
> >
> > + info->vproc_on_boot = regulator_get_voltage(info->proc_reg);
>
> This result is used only if we use ccifreq, so this should be
> enclosed in an if
> condition: this will spare us some (yes, small) time on devices that
> don't use it.
>
> if (info->soc_data->ccifreq_supported) {
> info->vproc_on_boot = regulator_get_voltage(info-
> >proc_reg);
> if (info->vproc_on_boot < 0) {
> dev_err(....
> goto ..
> }
> }
>
> P.S.: While at it, since the maximum width is 100 columns, the
> dev_err() call fits,
> so don't break that line!
>
> After the requested change:
>
> Reviewed-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@xxxxxxxxxxxxx>
I will add this in next version if there is no any suggestion for this
patch.
Thanks!
BRs,
Rex
