On Fri, 2022-04-15 at 14:14 +0800, Hsin-Yi Wang wrote:
> On Fri, Apr 15, 2022 at 1:59 PM Rex-BC Chen <rex-bc.chen@xxxxxxxxxxxx
> > wrote:
> >
> > To prevent infinite loop when tracking voltage, we calculate the
> > maximum
> > value for each platform data.
> > We assume min voltage is 0 and tracking target voltage using
> > min_volt_shift for each iteration.
> > The retry_max is 3 times of expeted iteration count.
> >
> > Signed-off-by: Rex-BC Chen <rex-bc.chen@xxxxxxxxxxxx>
> > ---
> > drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++++++
> > 1 file changed, 16 insertions(+)
> >
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c
> > b/drivers/cpufreq/mediatek-cpufreq.c
> > index cc44a7a9427a..d4c00237e862 100644
> > --- a/drivers/cpufreq/mediatek-cpufreq.c
> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
> > @@ -86,6 +86,16 @@ static int mtk_cpufreq_voltage_tracking(struct
> > mtk_cpu_dvfs_info *info,
> > struct regulator *proc_reg = info->proc_reg;
> > struct regulator *sram_reg = info->sram_reg;
> > int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret;
> > + int retry_max;
> > +
> > + /*
> > + * We assume min voltage is 0 and tracking target voltage
> > using
> > + * min_volt_shift for each iteration.
> > + * The retry_max is 3 times of expeted iteration count.
> > + */
> > + retry_max = 3 * DIV_ROUND_UP(max(info->soc_data-
> > >sram_max_volt,
> > + info->soc_data-
> > >proc_max_volt),
> > + info->soc_data-
> > >min_volt_shift);
>
> mtk_cpufreq_voltage_tracking() will be called very frequently.
> retry_max is the same every time mtk_cpufreq_voltage_tracking() is
> called. Is it better to calculate before and store in
> mtk_cpu_dvfs_info?
>
Hello Hsin-Yi,
Thanks for your reviwew.
I will do this in next version.
BRs,
Rex
> >
> > pre_vproc = regulator_get_voltage(proc_reg);
> > if (pre_vproc < 0) {
> > @@ -151,6 +161,12 @@ static int mtk_cpufreq_voltage_tracking(struct
> > mtk_cpu_dvfs_info *info,
> >
> > pre_vproc = vproc;
> > pre_vsram = vsram;
> > +
> > + if (--retry_max < 0) {
> > + dev_err(info->cpu_dev,
> > + "over loop count, failed to set
> > voltage\n");
> > + return -EINVAL;
> > + }
> > } while (vproc != new_vproc || vsram != new_vsram);
> >
> > return 0;
> > --
> > 2.18.0
> >
