> Subject: Re: [PATCH v6 01/20] clk: bump stdout clock usage for
> earlycon
>
> Hi Peng,
>
> On Fri, 2024-08-09 at 07:16 +0000, Peng Fan wrote:
> > > +static int __init of_clk_drop_stdout_clocks(void) {
> > > + for (size_t i = 0; i < of_clk_stdout_clks.n_clks; ++i) {
> > > + clk_disable_unprepare(of_clk_stdout_clks.clks[i]);
> > > + clk_put(of_clk_stdout_clks.clks[i]);
> > > + }
> > > +
> > > + kfree(of_clk_stdout_clks.clks);
> > > +
> > > + /*
> > > + * Do not try to acquire stdout clocks after late initcalls, e.g.
> > > + * during further module loading, as we then wouldn't have a
> > > way to
> > > + * drop the references (and associated allocations) ever again.
> > > + */
> > > + of_clk_stdout_clks.bump_refs = false;
> > > +
> > > + return 0;
> > > +}
> > > +late_initcall_sync(of_clk_drop_stdout_clocks);
> >
> > If the uart driver is built as module, this might break earlycon.
> > Before uart driver loaded, clk disabled per my understanding.
>
> You're right.
>
> With this in mind, I'm not sure then if a generic solution is possible...
>
> I guess it has to be duplicated into the platforms after all and platforms
> can enable this if they opt to disallow uart as module?
>
> Any other suggestions?
I not have good idea here. Put of_clk_drop_stdout_clocks after
bootconsole disabled might be ok.
Regards,
Peng.
>
> > > +
> > > /**
> > > * struct of_clk_provider - Clock provider registration structure
> > > * @link: Entry in global list of clock providers @@ -5031,6
> > > +5156,8 @@ int of_clk_add_provider(struct device_node *np,
> > >
> > > fwnode_dev_initialized(&np->fwnode, true);
> > >
> > > + of_clk_bump_stdout_clocks();
> > > +
> > > return ret;
> > > }
> > > EXPORT_SYMBOL_GPL(of_clk_add_provider);
> > > @@ -5073,6 +5200,8 @@ int of_clk_add_hw_provider(struct
> device_node
> > > *np,
> > >
> > > fwnode_dev_initialized(&np->fwnode, true);
> > >
> > > + of_clk_bump_stdout_clocks();
> >
> > If clock driver is built as module, the will make the clocks will be
> > always enabled, if my understanding is correct.
>
> until late_initcall_sync(), at which point it'll be disabled before the uart
> driver has probed, yes :-(
>
> Cheers,
> Andre'
