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linux-next/arch/mips/kernel/csrc-r4k.c
Deng-Cheng Zhu e9cef549c3 MIPS: csrc-r4k: Implement read_sched_clock
Use c0 count register for sched_clock source. This implementation will give
high resolution cputime accounting.

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: macro@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9478/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-04-01 17:21:27 +02:00

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C

/*
* 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) 2007 by Ralf Baechle
*/
#include <linux/clocksource.h>
#include <linux/init.h>
#include <linux/sched_clock.h>
#include <asm/time.h>
static cycle_t c0_hpt_read(struct clocksource *cs)
{
return read_c0_count();
}
static struct clocksource clocksource_mips = {
.name = "MIPS",
.read = c0_hpt_read,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static u64 notrace r4k_read_sched_clock(void)
{
return read_c0_count();
}
int __init init_r4k_clocksource(void)
{
if (!cpu_has_counter || !mips_hpt_frequency)
return -ENXIO;
/* Calculate a somewhat reasonable rating value */
clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
clocksource_register_hz(&clocksource_mips, mips_hpt_frequency);
sched_clock_register(r4k_read_sched_clock, 32, mips_hpt_frequency);
return 0;
}