From: Anton Blanchard <anton@samba•org>
To: benh@kernel•crashing.org, paulus@samba•org, johnstul@us•ibm.com
Cc: linuxppc-dev@lists•ozlabs.org
Subject: [PATCH 1/4] powerpc/time: Use clockevents_calc_mult_shift
Date: Thu, 03 Nov 2011 11:59:23 +1100 [thread overview]
Message-ID: <20111103010111.868598561@samba.org> (raw)
In-Reply-To: 20111103005922.854058953@samba.org
We can use clockevents_calc_mult_shift instead of doing all
the work ourselves.
Signed-off-by: Anton Blanchard <anton@samba•org>
---
Index: linux-build/arch/powerpc/kernel/time.c
===================================================================
--- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-03 10:19:55.225606490 +1100
+++ linux-build/arch/powerpc/kernel/time.c 2011-11-03 10:19:59.493679032 +1100
@@ -112,8 +112,6 @@ static void decrementer_set_mode(enum cl
static struct clock_event_device decrementer_clockevent = {
.name = "decrementer",
.rating = 200,
- .shift = 0, /* To be filled in */
- .mult = 0, /* To be filled in */
.irq = 0,
.set_next_event = decrementer_set_next_event,
.set_mode = decrementer_set_mode,
@@ -904,31 +902,6 @@ static void decrementer_set_mode(enum cl
decrementer_set_next_event(DECREMENTER_MAX, dev);
}
-static inline uint64_t div_sc64(unsigned long ticks, unsigned long nsec,
- int shift)
-{
- uint64_t tmp = ((uint64_t)ticks) << shift;
-
- do_div(tmp, nsec);
- return tmp;
-}
-
-static void __init setup_clockevent_multiplier(unsigned long hz)
-{
- u64 mult, shift = 32;
-
- while (1) {
- mult = div_sc64(hz, NSEC_PER_SEC, shift);
- if (mult && (mult >> 32UL) == 0UL)
- break;
-
- shift--;
- }
-
- decrementer_clockevent.shift = shift;
- decrementer_clockevent.mult = mult;
-}
-
static void register_decrementer_clockevent(int cpu)
{
struct clock_event_device *dec = &per_cpu(decrementers, cpu).event;
@@ -946,7 +919,8 @@ static void __init init_decrementer_cloc
{
int cpu = smp_processor_id();
- setup_clockevent_multiplier(ppc_tb_freq);
+ clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4);
+
decrementer_clockevent.max_delta_ns =
clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
decrementer_clockevent.min_delta_ns =
next prev parent reply other threads:[~2011-11-03 0:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-03 0:59 [PATCH 0/4] PowerPC time fixes Anton Blanchard
2011-11-03 0:59 ` Anton Blanchard [this message]
2011-11-03 0:59 ` [PATCH 2/4] powerpc/time: Use clocksource_register_hz Anton Blanchard
2011-11-03 13:14 ` John Stultz
2011-11-05 0:55 ` Paul Mackerras
2011-11-07 18:26 ` john stultz
2011-11-03 0:59 ` [PATCH 3/4] powerpc/time: Remove unnecessary sanity check of decrementer expiration Anton Blanchard
2011-11-03 0:59 ` [PATCH 4/4] powerpc/time: Fix some style issues Anton Blanchard
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