Re: [PATCH] opp: of: Allow lazy-linking of required-opps to non genpd

[Hsin-Yi Wang]

On Wed, Jun 16, 2021 at 5:09 PM Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
>
> On 16-06-21, 17:47, Chanwoo Choi wrote:
> > On 6/16/21 4:55 PM, Viresh Kumar wrote:
> > > On 16-06-21, 13:33, Hsin-Yi Wang wrote:
> > >> Don't limit required_opp_table to genpd only. One possible use case is
> > >> cpufreq based devfreq governor, which can use required-opps property to
> > >> derive devfreq from cpufreq.
> > >>
> > >> Suggested-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> > >> Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> > >> ---
> > >> This is tested with the non genpd case mt8183-cci with passive
> > >> governor[1].
> > >> [1] https://patchwork.kernel.org/project/linux-mediatek/patch/1616499241-4906-2-git-send-email-andrew-sh.cheng@xxxxxxxxxxxx/
> > >> ---
> > >>  drivers/opp/of.c | 20 +-------------------
> > >>  1 file changed, 1 insertion(+), 19 deletions(-)
> > >>
> > >> diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> > >> index aa75a1caf08a3..9573facce53a5 100644
> > >> --- a/drivers/opp/of.c
> > >> +++ b/drivers/opp/of.c
> > >> @@ -201,17 +201,6 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
> > >>                    lazy = true;
> > >>                    continue;
> > >>            }
> > >> -
> > >> -          /*
> > >> -           * We only support genpd's OPPs in the "required-opps" for now,
> > >> -           * as we don't know how much about other cases. Error out if the
> > >> -           * required OPP doesn't belong to a genpd.
> > >> -           */
> > >> -          if (!required_opp_tables[i]->is_genpd) {
> > >> -                  dev_err(dev, "required-opp doesn't belong to genpd: %pOF\n",
> > >> -                          required_np);
> > >> -                  goto free_required_tables;
> > >> -          }
> > >>    }
> > >>
> > >>    /* Let's do the linking later on */
> > >> @@ -379,13 +368,6 @@ static void lazy_link_required_opp_table(struct opp_table *new_table)
> > >>    struct dev_pm_opp *opp;
> > >>    int i, ret;
> > >>
> > >> -  /*
> > >> -   * We only support genpd's OPPs in the "required-opps" for now,
> > >> -   * as we don't know much about other cases.
> > >> -   */
> > >> -  if (!new_table->is_genpd)
> > >> -          return;
> > >> -
> > >>    mutex_lock(&opp_table_lock);
> > >>
> > >>    list_for_each_entry_safe(opp_table, temp, &lazy_opp_tables, lazy) {
> > >> @@ -873,7 +855,7 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
> > >>            return ERR_PTR(-ENOMEM);
> > >>
> > >>    ret = _read_opp_key(new_opp, opp_table, np, &rate_not_available);
> > >> -  if (ret < 0 && !opp_table->is_genpd) {
> > >> +  if (ret < 0) {
> > >>            dev_err(dev, "%s: opp key field not found\n", __func__);
> > >>            goto free_opp;
> > >>    }
> > >
> > > Plus this and few changes to commit log.
> > >
> > > diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> > > index e366218d6736..b335c077f215 100644
> > > --- a/drivers/opp/core.c
> > > +++ b/drivers/opp/core.c
> > > @@ -893,6 +893,16 @@ static int _set_required_opps(struct device *dev,
> > >         if (!required_opp_tables)
> > >                 return 0;
> > >
> > > +       /*
> > > +        * We only support genpd's OPPs in the "required-opps" for now, as we
> > > +        * don't know much about other use cases. Error out if the required OPP
> > > +        * doesn't belong to a genpd.
> > > +        */
> > > +       if (unlikely(!required_opp_tables[0]->is_genpd)) {
> > > +               dev_err(dev, "required-opps don't belong to a genpd\n");
> > > +               return -ENOENT;
> > > +       }
> > > +
> >
> > If you add this checking statement, I think that
> > when using dev_pm_opp_set_rate with required-opp property, it will be failed.
>
> Yes, that is exactly what I am trying to do here. Hsin already
> confirmed that you guys won't use this API, isn't ?

we used clk_set_rate() and regulator_set_voltage().
>
> The point here is that the _set_required_opps() function only updates
> the performance state of genpds today. So it won't work for you guys
> anyway.
>
> --
> viresh