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SubjectRe: [PATCH v5 3/3] PM / devfreq: Add required OPPs support to passive governor
On Thu, Feb 4, 2021 at 10:49 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 03-02-21, 17:24, Hsin-Yi Wang wrote:
> > From: Saravana Kannan <saravanak@google.com>
> >
> > Look at the required OPPs of the "parent" device to determine the OPP that
> > is required from the slave device managed by the passive governor. This
> > allows having mappings between a parent device and a slave device even when
> > they don't have the same number of OPPs.
> >
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
> > Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
> > Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> > ---
> > drivers/devfreq/governor_passive.c | 20 +++++++++++++++-----
> > 1 file changed, 15 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
> > index 63332e4a65ae8..8d92b1964f9c3 100644
> > --- a/drivers/devfreq/governor_passive.c
> > +++ b/drivers/devfreq/governor_passive.c
> > @@ -19,7 +19,7 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
> > = (struct devfreq_passive_data *)devfreq->data;
> > struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
> > unsigned long child_freq = ULONG_MAX;
> > - struct dev_pm_opp *opp;
> > + struct dev_pm_opp *opp = NULL, *p_opp = NULL;
>
> I would initialize p_opp to ERR_PTR(-ENODEV) to avoid using
> IS_ERR_OR_NULL. There is no need to initialize opp as well.
>
> > int i, count, ret = 0;
> >
> > /*
> > @@ -56,13 +56,20 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
> > * list of parent device. Because in this case, *freq is temporary
> > * value which is decided by ondemand governor.
> > */
> > - opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
> > - if (IS_ERR(opp)) {
> > - ret = PTR_ERR(opp);
> > + p_opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
> > + if (IS_ERR(p_opp)) {
> > + ret = PTR_ERR(p_opp);
> > goto out;
>
> Perhaps just return from here, the goto is useless here.
>
> > }
> >
> > - dev_pm_opp_put(opp);
> > + if (devfreq->opp_table && parent_devfreq->opp_table)
> > + opp = dev_pm_opp_xlate_required_opp(parent_devfreq->opp_table,
> > + devfreq->opp_table, p_opp);
> > + if (opp) {
>
> This needs to be part of the above if block itself, else the opp will
> always be NULL, isn't it ?
>
> > + *freq = dev_pm_opp_get_freq(opp);
> > + dev_pm_opp_put(opp);
> > + goto out;
> > + }
> >
> > /*
> > * Get the OPP table's index of decided freqeuncy by governor
> > @@ -89,6 +96,9 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
> > *freq = child_freq;
> >
> > out:
> > + if (!IS_ERR_OR_NULL(opp))
>
> you should be checking for p_opp here, isn't it ? And perhaps we don't
> need this check as well as p_opp can't be invalid here.
>
> > + dev_pm_opp_put(p_opp);
> > +
> > return ret;
> > }
> >
> > --
> > 2.30.0.365.g02bc693789-goog
>
Thanks for the review. I'll fix them and send next version

> --
> viresh

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