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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
*/
#include <linux/clocksource.h>
#include <linux/init.h>
#include <asm/time.h>
#include <asm/gic.h>
static cycle_t gic_hpt_read(struct clocksource *cs)
{
unsigned int hi, hi2, lo;
do {
GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_63_32), hi);
GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_31_00), lo);
GICREAD(GIC_REG(SHARED, GIC_SH_COUNTER_63_32), hi2);
} while (hi2 != hi);
return (((cycle_t) hi) << 32) + lo;
}
static struct clocksource gic_clocksource = {
.name = "GIC",
.read = gic_hpt_read,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
void __init gic_clocksource_init(unsigned int frequency)
{
unsigned int config, bits;
/* Calculate the clocksource mask. */
GICREAD(GIC_REG(SHARED, GIC_SH_CONFIG), config);
bits = 32 + ((config & GIC_SH_CONFIG_COUNTBITS_MSK) >>
(GIC_SH_CONFIG_COUNTBITS_SHF - 2));
/* Set clocksource mask. */
gic_clocksource.mask = CLOCKSOURCE_MASK(bits);
/* Calculate a somewhat reasonable rating value. */
gic_clocksource.rating = 200 + frequency / 10000000;
clocksource_register_hz(&gic_clocksource, frequency);
}
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