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SubjectRe: [PATCH v3 0/6] clocksource: rework Atmel TCB timer driver
On 29/03/2018 at 14:07:34 +0200, Daniel Lezcano wrote:
> On 29/03/2018 13:42, Alexandre Belloni wrote:
> > On 29/03/2018 at 13:31:18 +0200, Alexander Dahl wrote:
> >> Pretty sure. I rebuilt the whole BSP and added another line to the kernel
> >> source to see if the tree I applied the patches to, was actually built:
> >>
> >>
> >> diff --git a/drivers/clocksource/timer-atmel-tcb.c b/drivers/clocksource/timer-atmel-tcb.c
> >> index 7fde9cfbf203..f85affc74a86 100644
> >> --- a/drivers/clocksource/timer-atmel-tcb.c
> >> +++ b/drivers/clocksource/timer-atmel-tcb.c
> >> @@ -222,7 +222,8 @@ static int __init tc_clkevt_register(struct device_node *node,
> >> goto err_slow;
> >> clk_disable(tce.clk);
> >>
> >> - clockevents_config_and_register(&tce.clkevt, 32768, 1, bits - 1);
> >> + pr_info( "*** bits: 0x%x, BIT(bits): 0x%lx\n", bits, BIT(bits) );
> >> + clockevents_config_and_register(&tce.clkevt, 32768, 1, BIT(bits) - 1);
> >>
> >> ret = request_irq(tce.irq, tc_clkevt2_irq, IRQF_TIMER | IRQF_SHARED,
> >> tce.clkevt.name, &tce);
> >>
> >>
> >
> > I've just tested on a g20, old driver:
> > INT NAME RATE MAX
> > 16 [vel at91_tick,] 175 Ints/s (max: 231)
> > 19 [ vel tc_clkevt] 129 Ints/s (max: 129)
> >
> >
> > new driver:
> > INT NAME RATE MAX
> > 17 [vel timer@fffa] 129 Ints/s (max: 129)
> > 18 [ vel ttyS0] 175 Ints/s (max: 231)
>
> Can you give in both platforms how fast the clocksource wraps up ?
>

sam9g20, old:
clocksource: pit: mask: 0xfffffff max_cycles: 0xfffffff, max_idle_ns: 14370379250 ns
sched_clock: 32 bits at 100 Hz, resolution 10000000ns, wraps every 21474836475000000ns
clocksource: tcb_clksrc: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 114963034405 ns

sam9g20, new:
clocksource: timer@fffa0000:0,1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 114963034405 ns
sched_clock: 32 bits at 16MHz, resolution 60ns, wraps every 129171948513ns

sama5d4, old:
clocksource: pit: mask: 0x7ffffff max_cycles: 0x7ffffff, max_idle_ns: 10859434279 ns
sched_clock: 32 bits at 100 Hz, resolution 10000000ns, wraps every 21474836475000000ns
clocksource: tcb_clksrc: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 173750949719 ns

sama5d4, new:
clocksource: timer@fc024000:0: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 173750949719 ns
sched_clock: 32 bits at 11MHz, resolution 90ns, wraps every 195225786322ns

--
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

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