0f051dbe15
clock interrupts. Keep a 1-in-16 smoothed average of the length of each tick. If the CPU speed is correctly diagnosed, this should give experienced users enough information to figure out a more suitable value for `tick'.
103 lines
2.6 KiB
C
103 lines
2.6 KiB
C
/*
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* Kernel interface to machine-dependent clock driver.
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* Garrett Wollman, September 1994.
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* This file is in the public domain.
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*
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* $Id: clock.h,v 1.8 1995/12/24 08:10:49 davidg Exp $
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*/
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#ifndef _MACHINE_CLOCK_H_
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#define _MACHINE_CLOCK_H_
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#if defined(I586_CPU) || defined(I686_CPU)
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#define I586_CYCLECTR(x) \
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__asm __volatile(".byte 0x0f, 0x31" : "=A" (x))
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/*
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* When we update the clock, we also update this bias value which is
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* automatically subtracted in microtime(). We assume that CPU_THISTICKLEN()
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* has been called at some point in the past, so that an appropriate value is
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* set up in i586_last_tick. (This works even if we are not being called
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* from hardclock because hardclock will have run before and will made the
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* call.)
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*/
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#define CPU_CLOCKUPDATE(otime, ntime) \
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do { \
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if(i586_ctr_rate) { \
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disable_intr(); \
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i586_ctr_bias = i586_last_tick; \
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*(otime) = *(ntime); \
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enable_intr(); \
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} else { \
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*(otime) = *(ntime); \
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} \
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} while(0)
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#define CPU_THISTICKLEN(dflt) cpu_thisticklen(dflt)
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#else
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#define CPU_CLOCKUPDATE(otime, ntime) \
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(*(otime) = *(ntime))
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#define CPU_THISTICKLEN(dflt) dflt
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#endif
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#define I586_CTR_RATE_SHIFT 8
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#if defined(KERNEL) && !defined(LOCORE)
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#include <sys/cdefs.h>
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#include <machine/frame.h>
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/*
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* i386 to clock driver interface.
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* XXX almost all of it is misplaced. i586 stuff is done in isa/clock.c
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* and isa stuff is done in i386/microtime.s and i386/support.s.
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*/
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extern int adjkerntz;
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extern int disable_rtc_set;
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#if defined(I586_CPU) || defined(I686_CPU)
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extern unsigned i586_ctr_rate; /* fixed point */
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extern long long i586_last_tick;
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extern long long i586_ctr_bias;
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extern unsigned long i586_avg_tick;
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#endif
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extern int timer0_max_count;
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extern u_int timer0_overflow_threshold;
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extern u_int timer0_prescaler_count;
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#if defined(I586_CPU) || defined(I686_CPU)
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void calibrate_cyclecounter __P((void));
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#endif
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#if defined(I586_CPU) || defined(I686_CPU)
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static __inline u_long
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cpu_thisticklen(u_long dflt)
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{
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long long old;
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long len;
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if (i586_ctr_rate) {
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old = i586_last_tick;
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I586_CYCLECTR(i586_last_tick);
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len = ((i586_last_tick - old) << I586_CTR_RATE_SHIFT)
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/ i586_ctr_rate;
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i586_avg_tick = i586_avg_tick * 15 / 16 + len / 16;
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}
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return dflt;
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}
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#endif
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/*
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* Driver to clock driver interface.
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*/
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void DELAY __P((int usec));
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int acquire_timer0 __P((int rate,
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void (*function)(struct clockframe *frame)));
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int acquire_timer2 __P((int mode));
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int release_timer0 __P((void));
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int release_timer2 __P((void));
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int sysbeep __P((int pitch, int period));
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#endif /* KERNEL && !LOCORE */
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#endif /* !_MACHINE_CLOCK_H_ */
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