On Thu, 8 Nov 2018 12:36:35 +0200
Tero Kristo <t-kristo@xxxxxx> wrote:
> On 04/10/2018 23:38, Andreas Kemnade wrote:
> > We have the scenario that first autoidle is disabled for all clocks,
> > then it is disabled for selected ones and then enabled for all. So
> > we should have some counting here, also according to the
> > comment in _setup_iclk_autoidle()
> >
> > Signed-off-by: Andreas Kemnade <andreas@xxxxxxxxxxxx>
> > ---
> > drivers/clk/ti/autoidle.c | 32 ++++++++++++++++++++++++--------
> > include/linux/clk/ti.h | 1 +
> > 2 files changed, 25 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/clk/ti/autoidle.c b/drivers/clk/ti/autoidle.c
> > index 7bb9afbe4058..bb6cff168e73 100644
> > --- a/drivers/clk/ti/autoidle.c
> > +++ b/drivers/clk/ti/autoidle.c
> > @@ -37,6 +37,14 @@ struct clk_ti_autoidle {
> > static LIST_HEAD(autoidle_clks);
> > static LIST_HEAD(clk_hw_omap_clocks);
> >
> > +/*
> > + * we have some non-atomic read/write
> > + * operations behind it, so lets
> > + * take one mutex for handling autoidle
> > + * of all clocks
> > + */
> > +static DEFINE_MUTEX(autoidle_mutex);
>
> Why mutex? This prevents calling the autoidle APIs from atomic context.
> Did you check the mutex debug kernel configs with this?
>
Oops, I thought they were on, but they were not. OK,
I am preparing a v2 of this thing.
> This may cause problems with the runtime PM entries to the code at least.
>
>
> > +
> > /**
> > * omap2_clk_deny_idle - disable autoidle on an OMAP clock
> > * @clk: struct clk * to disable autoidle for
> > @@ -48,8 +56,13 @@ int omap2_clk_deny_idle(struct clk *clk)
> > struct clk_hw_omap *c;
> >
> > c = to_clk_hw_omap(__clk_get_hw(clk));
> > - if (c->ops && c->ops->deny_idle)
> > - c->ops->deny_idle(c);
> > + if (c->ops && c->ops->deny_idle) {
> > + mutex_lock(&autoidle_mutex);
> > + c->autoidle_count--;
> > + if (c->autoidle_count == -1)
>
> I think you should swap the arithmetics here, all the other usecounters
> use positive values, here you enter deep to the negative side when
> autoidle is denied by multiple users, which might be confusing.
>
agreed.
Regards,
Andreas
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