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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) 1998, 1999, 2003 by Ralf Baechle
*/
#ifndef _ASM_TIMEX_H
#define _ASM_TIMEX_H
#include <asm/mipsregs.h>
/*
* This is the frequency of the timer used for Linux's timer interrupt.
* The value should be defined as accurate as possible or under certain
* circumstances Linux timekeeping might become inaccurate or fail.
*
* For many system the exact clockrate of the timer isn't known but due to
* the way this value is used we can get away with a wrong value as long
* as this value is:
*
* - a multiple of HZ
* - a divisor of the actual rate
*
* 500000 is a good such cheat value.
*
* The obscure number 1193182 is the same as used by the original i8254
* time in legacy PC hardware; the chip unfortunately also found in a
* bunch of MIPS systems. The last remaining user of the i8254 for the
* timer interrupt is the RM200; it's a very standard system so there is
* no reason to make this a separate architecture.
*/
#include <timex.h>
/*
* Standard way to access the cycle counter.
* Currently only used on SMP for scheduling.
*
* Only the low 32 bits are available as a continuously counting entity.
* But this only means we'll force a reschedule every 8 seconds or so,
* which isn't an evil thing.
*
* We know that all SMP capable CPUs have cycle counters.
*/
typedef unsigned int cycles_t;
static inline cycles_t get_cycles (void)
{
return read_c0_count();
}
#endif /* _ASM_TIMEX_H */
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