提交 aab4673b 编写于 作者: J James Hogan 提交者: 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: NJames 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: NRalf Baechle <ralf@linux-mips.org>
上级 6b832257
......@@ -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);
......
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