[PATCH v2 4/4] clocksource: dw_apb_timer_of: use clocksource_of_init
Heiko Stübner
heiko at sntech.de
Wed Jun 5 01:06:29 EST 2013
Am Dienstag, 4. Juni 2013, 16:21:20 schrieb Jamie Iles:
> Hi Heiko,
>
> On Tue, Jun 04, 2013 at 11:38:42AM +0200, Heiko Stübner wrote:
> > dw_apb_timer_init used to search the devicetree for matching timer
> > devices, making calls to it from board files necessary.
> >
> > Change the dw_apb_timer_init to work with CLOCKSOURCE_OF_DECLARE.
> > With this change the function gets called once for each timer node
> > and tracks these number of calls to attach clockevent and clocksource
> > devices to the nodes.
> >
> > Also remove the calls to dw_apb_timer_init from all previous users, as
> > clocksource_of_init is the default for init_time now.
> >
> > Tested on the upcoming rk3066 code.
> >
> > Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> > Acked-by: Rob Herring <rob.herring at calxeda.com>
> > Acked-by: Arnd Bergmann <arnd at arndb.de>
> > ---
>
> ...
>
> > -void __init dw_apb_timer_init(void)
> > +static int num_called;
> > +static void __init dw_apb_timer_init(struct device_node *timer)
> >
> > {
> >
> > - struct device_node *event_timer, *source_timer;
> > -
> > - event_timer = of_find_matching_node(NULL, osctimer_ids);
> > - if (!event_timer)
> > - panic("No timer for clockevent");
> > - add_clockevent(event_timer);
> > -
> > - source_timer = of_find_matching_node(event_timer, osctimer_ids);
> > - if (!source_timer)
> > - panic("No timer for clocksource");
> > - add_clocksource(source_timer);
> > -
> > - of_node_put(source_timer);
> > + switch (num_called) {
> > + case 0:
> > + pr_debug("%s: found clockevent timer\n", __func__);
> > + add_clockevent(timer);
> > + of_node_put(timer);
> > + break;
> > + case 1:
> > + pr_debug("%s: found clocksource timer\n", __func__);
> > + add_clocksource(timer);
> > + of_node_put(timer);
> > + init_sched_clock();
> > + break;
> > + default:
> > + break;
> > + }
> >
> > - init_sched_clock();
> > + num_called++;
> >
> > }
> >
> > +CLOCKSOURCE_OF_DECLARE(pc3x2_timer, "picochip,pc3x2-timer",
> > dw_apb_timer_init); +CLOCKSOURCE_OF_DECLARE(apb_timer,
> > "snps,dw-apb-timer-osc", dw_apb_timer_init);
>
> I think maybe we also want CLOCKSOURCE_OF_DECLARE() instances for the
> contents of sptimer_ids for completeness, otherwise looks good.
Hmm ... difficult.
As you can see, currently we call init_sched_clock when the second timer is
found, which then tries to find the sptimer or uses the clocksource as
sched_clock.
So to use CLOCKSOURCE_OF_DECLARE for the sptimer the init_sched_clock call
would need to move to its init function. So on system without sptimer (like
mine) this third call would never happen, and the system would be missing a
sched_clock.
Or I just don't see the solution currently. In any case this could probably be
handled by someone with the relevant hardware to test ;-) .
> Acked-by: Jamie Iles <jamie at jamieiles.com>
thanks
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