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authorThomas Gleixner <tglx@linutronix.de>2011-05-14 12:06:36 +0200
committerThomas Gleixner <tglx@linutronix.de>2011-05-14 12:06:36 +0200
commita18f22a968de17b29f2310cdb7ba69163e65ec15 (patch)
treea7d56d88fad5e444d7661484109758a2f436129e /arch/mips/kernel/i8253.c
parenta1c57e0fec53defe745e64417eacdbd3618c3e66 (diff)
parent798778b8653f64b7b2162ac70eca10367cff6ce8 (diff)
downloadtalos-obmc-linux-a18f22a968de17b29f2310cdb7ba69163e65ec15.tar.gz
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Merge branch 'consolidate-clksrc-i8253' of master.kernel.org:~rmk/linux-2.6-arm into timers/clocksource
Conflicts: arch/ia64/kernel/cyclone.c arch/mips/kernel/i8253.c arch/x86/kernel/i8253.c Reason: Resolve conflicts so further cleanups do not conflict further Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/mips/kernel/i8253.c')
-rw-r--r--arch/mips/kernel/i8253.c75
1 files changed, 1 insertions, 74 deletions
diff --git a/arch/mips/kernel/i8253.c b/arch/mips/kernel/i8253.c
index 9fadd17888d9..391221b6a6aa 100644
--- a/arch/mips/kernel/i8253.c
+++ b/arch/mips/kernel/i8253.c
@@ -125,84 +125,11 @@ void __init setup_pit_timer(void)
setup_irq(0, &irq0);
}
-/*
- * Since the PIT overflows every tick, its not very useful
- * to just read by itself. So use jiffies to emulate a free
- * running counter:
- */
-static cycle_t pit_read(struct clocksource *cs)
-{
- unsigned long flags;
- int count;
- u32 jifs;
- static int old_count;
- static u32 old_jifs;
-
- raw_spin_lock_irqsave(&i8253_lock, flags);
- /*
- * Although our caller may have the read side of xtime_lock,
- * this is now a seqlock, and we are cheating in this routine
- * by having side effects on state that we cannot undo if
- * there is a collision on the seqlock and our caller has to
- * retry. (Namely, old_jifs and old_count.) So we must treat
- * jiffies as volatile despite the lock. We read jiffies
- * before latching the timer count to guarantee that although
- * the jiffies value might be older than the count (that is,
- * the counter may underflow between the last point where
- * jiffies was incremented and the point where we latch the
- * count), it cannot be newer.
- */
- jifs = jiffies;
- outb_p(0x00, PIT_MODE); /* latch the count ASAP */
- count = inb_p(PIT_CH0); /* read the latched count */
- count |= inb_p(PIT_CH0) << 8;
-
- /* VIA686a test code... reset the latch if count > max + 1 */
- if (count > LATCH) {
- outb_p(0x34, PIT_MODE);
- outb_p(LATCH & 0xff, PIT_CH0);
- outb(LATCH >> 8, PIT_CH0);
- count = LATCH - 1;
- }
-
- /*
- * It's possible for count to appear to go the wrong way for a
- * couple of reasons:
- *
- * 1. The timer counter underflows, but we haven't handled the
- * resulting interrupt and incremented jiffies yet.
- * 2. Hardware problem with the timer, not giving us continuous time,
- * the counter does small "jumps" upwards on some Pentium systems,
- * (see c't 95/10 page 335 for Neptun bug.)
- *
- * Previous attempts to handle these cases intelligently were
- * buggy, so we just do the simple thing now.
- */
- if (count > old_count && jifs == old_jifs) {
- count = old_count;
- }
- old_count = count;
- old_jifs = jifs;
-
- raw_spin_unlock_irqrestore(&i8253_lock, flags);
-
- count = (LATCH - 1) - count;
-
- return (cycle_t)(jifs * LATCH) + count;
-}
-
-static struct clocksource clocksource_pit = {
- .name = "pit",
- .rating = 110,
- .read = pit_read,
- .mask = CLOCKSOURCE_MASK(32),
-};
-
static int __init init_pit_clocksource(void)
{
if (num_possible_cpus() > 1) /* PIT does not scale! */
return 0;
- return clocksource_register_hz(&clocksource_pit, CLOCK_TICK_RATE);
+ return clocksource_i8253_init();
}
arch_initcall(init_pit_clocksource);
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