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