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

arch/mips/mti-malta/malta-time.c

+5 −5
Original line number Diff line number Diff line
@@ -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);