Commit aab4673b authored by James Hogan's avatar James Hogan Committed by Ralf Baechle

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

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: default avatarJames 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: default avatarRalf Baechle <ralf@linux-mips.org>
parent 6b832257
...@@ -81,16 +81,16 @@ static void __init estimate_frequencies(void) ...@@ -81,16 +81,16 @@ static void __init estimate_frequencies(void)
local_irq_save(flags); 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);
while (!(CMOS_READ(RTC_REG_A) & RTC_UIP)); while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
/* Initialize counters. */
start = read_c0_count(); start = read_c0_count();
if (gic_present) { if (gic_present)
gic_start_count();
gicstart = gic_read_count(); gicstart = gic_read_count();
}
/* Read counter exactly on falling edge of update flag. */ /* 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);
......
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