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/* $OpenBSD: clock.c,v 1.30 2020/05/01 19:56:11 kettenis Exp $ */
/*
* Copyright (c) 1998-2003 Michael Shalayeff
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/timetc.h>
#include <dev/clock_subr.h>
#include <machine/pdc.h>
#include <machine/iomod.h>
#include <machine/psl.h>
#include <machine/intr.h>
#include <machine/reg.h>
#include <machine/cpufunc.h>
#include <machine/autoconf.h>
u_long cpu_hzticks;
int cpu_hardclock(void *);
u_int itmr_get_timecount(struct timecounter *);
struct timecounter itmr_timecounter = {
itmr_get_timecount, NULL, 0xffffffff, 0, "itmr", 0, NULL
};
extern todr_chip_handle_t todr_handle;
struct todr_chip_handle pdc_todr;
int
pdc_gettime(struct todr_chip_handle *handle, struct timeval *tv)
{
struct pdc_tod tod PDC_ALIGNMENT;
int error;
if ((error = pdc_call((iodcio_t)pdc, 1, PDC_TOD, PDC_TOD_READ,
&tod, 0, 0, 0, 0, 0))) {
printf("clock: failed to fetch (%d)\n", error);
return EIO;
}
tv->tv_sec = tod.sec;
tv->tv_usec = tod.usec;
return 0;
}
int
pdc_settime(struct todr_chip_handle *handle, struct timeval *tv)
{
int error;
if ((error = pdc_call((iodcio_t)pdc, 1, PDC_TOD, PDC_TOD_WRITE,
tv->tv_sec, tv->tv_usec))) {
printf("clock: failed to save (%d)\n", error);
return EIO;
}
return 0;
}
void
cpu_initclocks(void)
{
struct cpu_info *ci = curcpu();
u_long __itmr;
pdc_todr.todr_gettime = pdc_gettime;
pdc_todr.todr_settime = pdc_settime;
todr_handle = &pdc_todr;
cpu_hzticks = (PAGE0->mem_10msec * 100) / hz;
itmr_timecounter.tc_frequency = PAGE0->mem_10msec * 100;
tc_init(&itmr_timecounter);
mfctl(CR_ITMR, __itmr);
ci->ci_itmr = __itmr;
__itmr += cpu_hzticks;
mtctl(__itmr, CR_ITMR);
}
int
cpu_hardclock(void *v)
{
struct cpu_info *ci = curcpu();
u_long __itmr, delta, eta;
int wrap;
register_t eiem;
/*
* Invoke hardclock as many times as there has been cpu_hzticks
* ticks since the last interrupt.
*/
for (;;) {
mfctl(CR_ITMR, __itmr);
delta = __itmr - ci->ci_itmr;
if (delta >= cpu_hzticks) {
hardclock(v);
ci->ci_itmr += cpu_hzticks;
} else
break;
}
/*
* Program the next clock interrupt, making sure it will
* indeed happen in the future. This is done with interrupts
* disabled to avoid a possible race.
*/
eta = ci->ci_itmr + cpu_hzticks;
wrap = eta < ci->ci_itmr; /* watch out for a wraparound */
__asm volatile("mfctl %%cr15, %0": "=r" (eiem));
__asm volatile("mtctl %r0, %cr15");
mtctl(eta, CR_ITMR);
mfctl(CR_ITMR, __itmr);
/*
* If we were close enough to the next tick interrupt
* value, by the time we have programmed itmr, it might
* have passed the value, which would cause a complete
* cycle until the next interrupt occurs. On slow
* models, this would be a disaster (a complete cycle
* taking over two minutes on a 715/33).
*
* We expect that it will only be necessary to postpone
* the interrupt once. Thus, there are two cases:
* - We are expecting a wraparound: eta < cpu_itmr.
* itmr is in tracks if either >= cpu_itmr or < eta.
* - We are not wrapping: eta > cpu_itmr.
* itmr is in tracks if >= cpu_itmr and < eta (we need
* to keep the >= cpu_itmr test because itmr might wrap
* before eta does).
*/
if ((wrap && !(eta > __itmr || __itmr >= ci->ci_itmr)) ||
(!wrap && !(eta > __itmr && __itmr >= ci->ci_itmr))) {
eta += cpu_hzticks;
mtctl(eta, CR_ITMR);
}
__asm volatile("mtctl %0, %%cr15":: "r" (eiem));
return (1);
}
void
setstatclockrate(int newhz)
{
/* nothing we can do */
}
u_int
itmr_get_timecount(struct timecounter *tc)
{
u_long __itmr;
mfctl(CR_ITMR, __itmr);
return (__itmr);
}
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