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MIPS: malta-time: Start GIC count before syncing to RTC

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The sampling of the GIC counter on Malta after observing a rising edge
of the RTC update flag differs slightly between the first and second
sample, with the first sample also calling gic_start_count(). The two
samples should really be taken as similarly as possible to get the most
accurate figure, so move the gic_start_count() call before detecting the
rising edge.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13173/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
James Hogan 2016-04-22 18:19:14 +01:00 committed by Ralf Baechle
parent 6b8322576e
commit aab4673b59
1 changed files with 5 additions and 5 deletions
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10
arch/mips/mti-malta/malta-time.c
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@ -81,16 +81,16 @@ static void __init estimate_frequencies(void)
local_irq_save(flags);
/* Start counter exactly on falling edge of update flag. */
if (gic_present)
gic_start_count();
/* Read counter exactly on falling edge of update flag. */
while (CMOS_READ(RTC_REG_A) & RTC_UIP);
while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
/* Initialize counters. */
start = read_c0_count();
if (gic_present) {
gic_start_count();
if (gic_present)
gicstart = gic_read_count();
}
/* Read counter exactly on falling edge of update flag. */
while (CMOS_READ(RTC_REG_A) & RTC_UIP);