linux-sg2042/include/asm-ia64/timex.h

43 lines
1.3 KiB
C

#ifndef _ASM_IA64_TIMEX_H
#define _ASM_IA64_TIMEX_H
/*
* Copyright (C) 1998-2001, 2003 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
/*
* 2001/01/18 davidm Removed CLOCK_TICK_RATE. It makes no sense on IA-64.
* Also removed cacheflush_time as it's entirely unused.
*/
#include <asm/intrinsics.h>
#include <asm/processor.h>
typedef unsigned long cycles_t;
extern void (*ia64_udelay)(unsigned long usecs);
/*
* For performance reasons, we don't want to define CLOCK_TICK_TRATE as
* local_cpu_data->itc_rate. Fortunately, we don't have to, either: according to George
* Anzinger, 1/CLOCK_TICK_RATE is taken as the resolution of the timer clock. The time
* calculation assumes that you will use enough of these so that your tick size <= 1/HZ.
* If the calculation shows that your CLOCK_TICK_RATE can not supply exactly 1/HZ ticks,
* the actual value is calculated and used to update the wall clock each jiffie. Setting
* the CLOCK_TICK_RATE to x*HZ insures that the calculation will find no errors. Hence we
* pick a multiple of HZ which gives us a (totally virtual) CLOCK_TICK_RATE of about
* 100MHz.
*/
#define CLOCK_TICK_RATE (HZ * 100000UL)
static inline cycles_t
get_cycles (void)
{
cycles_t ret;
ret = ia64_getreg(_IA64_REG_AR_ITC);
return ret;
}
#endif /* _ASM_IA64_TIMEX_H */