On Sun, 2017-06-11 at 23:26 +0200, Linus Walleij wrote: > This timer is often used on the ARM architecture, so as with so > many siblings, we can implement delay timers, removing the need > for the system to calibrate jiffys at boot, and potentially > handling CPU frequency scaling on targets. > > We cannot just protect the Kconfig with a "depends on ARM" because > it is already known that different architectures are using Faraday > IP blocks, so it is better to make things open-ended and use
Seems like we're missing the end of the sentence? > > Result on boot dmesg: > > Switching to timer-based delay loop, resolution 40n > Calibrating delay loop (skipped), value calculated using > timer frequency.. 50.00 BogoMIPS (lpj=250000) > > This is accurately the timer frequency, 250MHz on the APB > bus. > > > Cc: Andrew Jeffery <[email protected]> > > Cc: Joel Stanley <[email protected]> > > Cc: Jonas Jensen <[email protected]> > Signed-off-by: Linus Walleij <[email protected]> Tried both patches on an AST2500, everything worked as suggested. Tested-by: Andrew Jeffery <[email protected]> > --- > drivers/clocksource/timer-fttmr010.c | 35 ++++++++++++++++++++++++++++++++++- > 1 file changed, 34 insertions(+), 1 deletion(-) > > diff --git a/drivers/clocksource/timer-fttmr010.c > b/drivers/clocksource/timer-fttmr010.c > index 5e82469995cb..0074d89cd2ce 100644 > --- a/drivers/clocksource/timer-fttmr010.c > +++ b/drivers/clocksource/timer-fttmr010.c > @@ -17,6 +17,7 @@ > #include <linux/clk.h> > #include <linux/slab.h> > #include <linux/bitops.h> > +#include <linux/delay.h> > > /* > * Register definitions for the timers > @@ -81,9 +82,15 @@ struct fttmr010 { > > bool count_down; > > u32 t1_enable_val; > > struct clock_event_device clkevt; > +#ifdef CONFIG_ARM > > + struct delay_timer delay_timer; > +#endif > }; > > -/* A local singleton used by sched_clock, which is stateless */ > +/* > + * A local singleton used by sched_clock and delay timer reads, which are > + * fast and stateless > + */ > static struct fttmr010 *local_fttmr; > > static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt) > @@ -101,6 +108,20 @@ static u64 notrace fttmr010_read_sched_clock_down(void) > > return ~readl(local_fttmr->base + TIMER2_COUNT); > } > > +#ifdef CONFIG_ARM > + > +static unsigned long fttmr010_read_current_timer_up(void) > +{ > > + return readl(local_fttmr->base + TIMER2_COUNT); > +} > + > +static unsigned long fttmr010_read_current_timer_down(void) > +{ > > + return ~readl(local_fttmr->base + TIMER2_COUNT); > +} > + > +#endif > + > static int fttmr010_timer_set_next_event(unsigned long cycles, > > struct clock_event_device *evt) > { > @@ -349,6 +370,18 @@ static int __init fttmr010_timer_init(struct device_node > *np) > > fttmr010->tick_rate, > > 1, 0xffffffff); > > +#ifdef CONFIG_ARM > > + /* Also use this timer for delays */ > > + if (fttmr010->count_down) > > + fttmr010->delay_timer.read_current_timer = > > + fttmr010_read_current_timer_down; > > + else > > + fttmr010->delay_timer.read_current_timer = > > + fttmr010_read_current_timer_up; > > + fttmr010->delay_timer.freq = fttmr010->tick_rate; > > + register_current_timer_delay(&fttmr010->delay_timer); > +#endif > + > > return 0; > > out_unmap:
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