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/*
* linux/arch/arm/plat-versatile/sched-clock.c
*
* Copyright (C) 1999 - 2003 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/io.h>
#include <linux/sched.h>
#include <asm/sched_clock.h>
#include <plat/sched_clock.h>
static DEFINE_CLOCK_DATA(cd);
static void __iomem *ctr;
/*
* Constants generated by clocks_calc_mult_shift(m, s, 24MHz, NSEC_PER_SEC, 60).
* This gives a resolution of about 41ns and a wrap period of about 178s.
*/
#define SC_MULT 2796202667u
#define SC_SHIFT 26
unsigned long long notrace sched_clock(void)
{
if (ctr) {
u32 cyc = readl(ctr);
return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0,
SC_MULT, SC_SHIFT);
} else
return 0;
}
static void notrace versatile_update_sched_clock(void)
{
u32 cyc = readl(ctr);
update_sched_clock(&cd, cyc, (u32)~0);
}
void __init versatile_sched_clock_init(void __iomem *reg, unsigned long rate)
{
ctr = reg;
init_fixed_sched_clock(&cd, versatile_update_sched_clock,
32, rate, SC_MULT, SC_SHIFT);
}
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