9350db19e7
- Don't print out meaningless iCOMP numbers, those are for droids. - Use a shorter wait to determine clock rate to avoid deficiencies in DELAY(). - Use a fixed-point representation with 8 bits of fraction to store the rate and rationalize the variable name. It would be possible to use even more fraction if it turns out to be worthwhile (I rather doubt it). The question of source code arrangement remains unaddressed.
105 lines
2.4 KiB
C
105 lines
2.4 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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* $Id$
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*/
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#ifndef _MACHINE_CLOCK_H_
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#define _MACHINE_CLOCK_H_
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#ifdef I586_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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#ifdef I586_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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#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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#ifdef I586_CPU
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void calibrate_cyclecounter __P((void));
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#endif
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void clkintr __P((struct clockframe frame));
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void rtcintr __P((struct clockframe frame));
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#ifdef I586_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 rv;
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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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rv = ((i586_last_tick - old) << I586_CTR_RATE_SHIFT)
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/ i586_ctr_rate;
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} else {
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rv = dflt;
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}
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return rv;
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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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