freebsd-dev/sys/i386/isa/clock.c
2009-06-23 23:16:37 +00:00

705 lines
17 KiB
C

/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz and Don Ahn.
*
* 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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 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.
*
* from: @(#)clock.c 7.2 (Berkeley) 5/12/91
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Routines to handle clock hardware.
*/
#include "opt_apic.h"
#include "opt_clock.h"
#include "opt_kdtrace.h"
#include "opt_isa.h"
#include "opt_mca.h"
#include "opt_xbox.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/lock.h>
#include <sys/kdb.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/timetc.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <machine/clock.h>
#include <machine/cpu.h>
#include <machine/frame.h>
#include <machine/intr_machdep.h>
#include <machine/md_var.h>
#ifdef DEV_APIC
#include <machine/apicvar.h>
#endif
#include <machine/ppireg.h>
#include <machine/timerreg.h>
#include <machine/smp.h>
#include <isa/rtc.h>
#ifdef DEV_ISA
#include <isa/isareg.h>
#include <isa/isavar.h>
#endif
#ifdef DEV_MCA
#include <i386/bios/mca_machdep.h>
#endif
#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
#endif
#define TIMER_DIV(x) ((i8254_freq + (x) / 2) / (x))
int clkintr_pending;
static int pscnt = 1;
static int psdiv = 1;
#ifndef TIMER_FREQ
#define TIMER_FREQ 1193182
#endif
u_int i8254_freq = TIMER_FREQ;
TUNABLE_INT("hw.i8254.freq", &i8254_freq);
int i8254_max_count;
static int i8254_real_max_count;
struct mtx clock_lock;
static struct intsrc *i8254_intsrc;
static u_int32_t i8254_lastcount;
static u_int32_t i8254_offset;
static int (*i8254_pending)(struct intsrc *);
static int i8254_ticked;
static int using_atrtc_timer;
static int using_lapic_timer;
/* Values for timerX_state: */
#define RELEASED 0
#define RELEASE_PENDING 1
#define ACQUIRED 2
#define ACQUIRE_PENDING 3
static u_char timer2_state;
static unsigned i8254_get_timecount(struct timecounter *tc);
static unsigned i8254_simple_get_timecount(struct timecounter *tc);
static void set_i8254_freq(u_int freq, int intr_freq);
static struct timecounter i8254_timecounter = {
i8254_get_timecount, /* get_timecount */
0, /* no poll_pps */
~0u, /* counter_mask */
0, /* frequency */
"i8254", /* name */
0 /* quality */
};
int
hardclockintr(struct trapframe *frame)
{
if (PCPU_GET(cpuid) == 0)
hardclock(TRAPF_USERMODE(frame), TRAPF_PC(frame));
else
hardclock_cpu(TRAPF_USERMODE(frame));
return (FILTER_HANDLED);
}
int
statclockintr(struct trapframe *frame)
{
profclockintr(frame);
statclock(TRAPF_USERMODE(frame));
return (FILTER_HANDLED);
}
int
profclockintr(struct trapframe *frame)
{
if (!using_atrtc_timer)
hardclockintr(frame);
if (profprocs != 0)
profclock(TRAPF_USERMODE(frame), TRAPF_PC(frame));
return (FILTER_HANDLED);
}
static int
clkintr(struct trapframe *frame)
{
if (timecounter->tc_get_timecount == i8254_get_timecount) {
mtx_lock_spin(&clock_lock);
if (i8254_ticked)
i8254_ticked = 0;
else {
i8254_offset += i8254_max_count;
i8254_lastcount = 0;
}
clkintr_pending = 0;
mtx_unlock_spin(&clock_lock);
}
KASSERT(!using_lapic_timer, ("clk interrupt enabled with lapic timer"));
#ifdef KDTRACE_HOOKS
/*
* If the DTrace hooks are configured and a callback function
* has been registered, then call it to process the high speed
* timers.
*/
int cpu = PCPU_GET(cpuid);
if (lapic_cyclic_clock_func[cpu] != NULL)
(*lapic_cyclic_clock_func[cpu])(frame);
#endif
if (using_atrtc_timer) {
#ifdef SMP
if (smp_started)
ipi_all_but_self(IPI_HARDCLOCK);
#endif
hardclockintr(frame);
} else {
if (--pscnt <= 0) {
pscnt = psratio;
#ifdef SMP
if (smp_started)
ipi_all_but_self(IPI_STATCLOCK);
#endif
statclockintr(frame);
} else {
#ifdef SMP
if (smp_started)
ipi_all_but_self(IPI_PROFCLOCK);
#endif
profclockintr(frame);
}
}
#ifdef DEV_MCA
/* Reset clock interrupt by asserting bit 7 of port 0x61 */
if (MCA_system)
outb(0x61, inb(0x61) | 0x80);
#endif
return (FILTER_HANDLED);
}
int
timer_spkr_acquire(void)
{
int mode;
mode = TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT;
if (timer2_state != RELEASED)
return (-1);
timer2_state = ACQUIRED;
/*
* This access to the timer registers is as atomic as possible
* because it is a single instruction. We could do better if we
* knew the rate. Use of splclock() limits glitches to 10-100us,
* and this is probably good enough for timer2, so we aren't as
* careful with it as with timer0.
*/
outb(TIMER_MODE, TIMER_SEL2 | (mode & 0x3f));
ppi_spkr_on(); /* enable counter2 output to speaker */
return (0);
}
int
timer_spkr_release(void)
{
if (timer2_state != ACQUIRED)
return (-1);
timer2_state = RELEASED;
outb(TIMER_MODE, TIMER_SEL2 | TIMER_SQWAVE | TIMER_16BIT);
ppi_spkr_off(); /* disable counter2 output to speaker */
return (0);
}
void
timer_spkr_setfreq(int freq)
{
freq = i8254_freq / freq;
mtx_lock_spin(&clock_lock);
outb(TIMER_CNTR2, freq & 0xff);
outb(TIMER_CNTR2, freq >> 8);
mtx_unlock_spin(&clock_lock);
}
/*
* This routine receives statistical clock interrupts from the RTC.
* As explained above, these occur at 128 interrupts per second.
* When profiling, we receive interrupts at a rate of 1024 Hz.
*
* This does not actually add as much overhead as it sounds, because
* when the statistical clock is active, the hardclock driver no longer
* needs to keep (inaccurate) statistics on its own. This decouples
* statistics gathering from scheduling interrupts.
*
* The RTC chip requires that we read status register C (RTC_INTR)
* to acknowledge an interrupt, before it will generate the next one.
* Under high interrupt load, rtcintr() can be indefinitely delayed and
* the clock can tick immediately after the read from RTC_INTR. In this
* case, the mc146818A interrupt signal will not drop for long enough
* to register with the 8259 PIC. If an interrupt is missed, the stat
* clock will halt, considerably degrading system performance. This is
* why we use 'while' rather than a more straightforward 'if' below.
* Stat clock ticks can still be lost, causing minor loss of accuracy
* in the statistics, but the stat clock will no longer stop.
*/
static int
rtcintr(struct trapframe *frame)
{
int flag = 0;
while (rtcin(RTC_INTR) & RTCIR_PERIOD) {
flag = 1;
if (--pscnt <= 0) {
pscnt = psdiv;
#ifdef SMP
if (smp_started)
ipi_all_but_self(IPI_STATCLOCK);
#endif
statclockintr(frame);
} else {
#ifdef SMP
if (smp_started)
ipi_all_but_self(IPI_PROFCLOCK);
#endif
profclockintr(frame);
}
}
return(flag ? FILTER_HANDLED : FILTER_STRAY);
}
static int
getit(void)
{
int high, low;
mtx_lock_spin(&clock_lock);
/* Select timer0 and latch counter value. */
outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
low = inb(TIMER_CNTR0);
high = inb(TIMER_CNTR0);
mtx_unlock_spin(&clock_lock);
return ((high << 8) | low);
}
/*
* Wait "n" microseconds.
* Relies on timer 1 counting down from (i8254_freq / hz)
* Note: timer had better have been programmed before this is first used!
*/
void
DELAY(int n)
{
int delta, prev_tick, tick, ticks_left;
#ifdef DELAYDEBUG
int getit_calls = 1;
int n1;
static int state = 0;
#endif
if (tsc_freq != 0 && !tsc_is_broken) {
uint64_t start, end, now;
sched_pin();
start = rdtsc();
end = start + (tsc_freq * n) / 1000000;
do {
cpu_spinwait();
now = rdtsc();
} while (now < end || (now > start && end < start));
sched_unpin();
return;
}
#ifdef DELAYDEBUG
if (state == 0) {
state = 1;
for (n1 = 1; n1 <= 10000000; n1 *= 10)
DELAY(n1);
state = 2;
}
if (state == 1)
printf("DELAY(%d)...", n);
#endif
/*
* Read the counter first, so that the rest of the setup overhead is
* counted. Guess the initial overhead is 20 usec (on most systems it
* takes about 1.5 usec for each of the i/o's in getit(). The loop
* takes about 6 usec on a 486/33 and 13 usec on a 386/20. The
* multiplications and divisions to scale the count take a while).
*
* However, if ddb is active then use a fake counter since reading
* the i8254 counter involves acquiring a lock. ddb must not do
* locking for many reasons, but it calls here for at least atkbd
* input.
*/
#ifdef KDB
if (kdb_active)
prev_tick = 1;
else
#endif
prev_tick = getit();
n -= 0; /* XXX actually guess no initial overhead */
/*
* Calculate (n * (i8254_freq / 1e6)) without using floating point
* and without any avoidable overflows.
*/
if (n <= 0)
ticks_left = 0;
else if (n < 256)
/*
* Use fixed point to avoid a slow division by 1000000.
* 39099 = 1193182 * 2^15 / 10^6 rounded to nearest.
* 2^15 is the first power of 2 that gives exact results
* for n between 0 and 256.
*/
ticks_left = ((u_int)n * 39099 + (1 << 15) - 1) >> 15;
else
/*
* Don't bother using fixed point, although gcc-2.7.2
* generates particularly poor code for the long long
* division, since even the slow way will complete long
* before the delay is up (unless we're interrupted).
*/
ticks_left = ((u_int)n * (long long)i8254_freq + 999999)
/ 1000000;
while (ticks_left > 0) {
#ifdef KDB
if (kdb_active) {
inb(0x84);
tick = prev_tick - 1;
if (tick <= 0)
tick = i8254_max_count;
} else
#endif
tick = getit();
#ifdef DELAYDEBUG
++getit_calls;
#endif
delta = prev_tick - tick;
prev_tick = tick;
if (delta < 0) {
delta += i8254_max_count;
/*
* Guard against i8254_max_count being wrong.
* This shouldn't happen in normal operation,
* but it may happen if set_i8254_freq() is
* traced.
*/
if (delta < 0)
delta = 0;
}
ticks_left -= delta;
}
#ifdef DELAYDEBUG
if (state == 1)
printf(" %d calls to getit() at %d usec each\n",
getit_calls, (n + 5) / getit_calls);
#endif
}
static void
set_i8254_freq(u_int freq, int intr_freq)
{
int new_i8254_real_max_count;
i8254_timecounter.tc_frequency = freq;
mtx_lock_spin(&clock_lock);
i8254_freq = freq;
if (using_lapic_timer)
new_i8254_real_max_count = 0x10000;
else
new_i8254_real_max_count = TIMER_DIV(intr_freq);
if (new_i8254_real_max_count != i8254_real_max_count) {
i8254_real_max_count = new_i8254_real_max_count;
if (i8254_real_max_count == 0x10000)
i8254_max_count = 0xffff;
else
i8254_max_count = i8254_real_max_count;
outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
outb(TIMER_CNTR0, i8254_real_max_count & 0xff);
outb(TIMER_CNTR0, i8254_real_max_count >> 8);
}
mtx_unlock_spin(&clock_lock);
}
static void
i8254_restore(void)
{
mtx_lock_spin(&clock_lock);
outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
outb(TIMER_CNTR0, i8254_real_max_count & 0xff);
outb(TIMER_CNTR0, i8254_real_max_count >> 8);
mtx_unlock_spin(&clock_lock);
}
/*
* Restore all the timers non-atomically (XXX: should be atomically).
*
* This function is called from pmtimer_resume() to restore all the timers.
* This should not be necessary, but there are broken laptops that do not
* restore all the timers on resume.
*/
void
timer_restore(void)
{
i8254_restore(); /* restore i8254_freq and hz */
atrtc_restore(); /* reenable RTC interrupts */
}
/* This is separate from startrtclock() so that it can be called early. */
void
i8254_init(void)
{
mtx_init(&clock_lock, "clk", NULL, MTX_SPIN | MTX_NOPROFILE);
set_i8254_freq(i8254_freq, hz);
}
void
startrtclock()
{
atrtc_start();
set_i8254_freq(i8254_freq, hz);
tc_init(&i8254_timecounter);
init_TSC();
}
/*
* Start both clocks running.
*/
void
cpu_initclocks()
{
#ifdef DEV_APIC
using_lapic_timer = lapic_setup_clock();
#endif
/*
* If we aren't using the local APIC timer to drive the kernel
* clocks, setup the interrupt handler for the 8254 timer 0 so
* that it can drive hardclock(). Otherwise, change the 8254
* timecounter to user a simpler algorithm.
*/
if (!using_lapic_timer) {
intr_add_handler("clk", 0, (driver_filter_t *)clkintr, NULL,
NULL, INTR_TYPE_CLK, NULL);
i8254_intsrc = intr_lookup_source(0);
if (i8254_intsrc != NULL)
i8254_pending =
i8254_intsrc->is_pic->pic_source_pending;
} else {
i8254_timecounter.tc_get_timecount =
i8254_simple_get_timecount;
i8254_timecounter.tc_counter_mask = 0xffff;
set_i8254_freq(i8254_freq, hz);
}
/* Initialize RTC. */
atrtc_start();
/*
* If the separate statistics clock hasn't been explicility disabled
* and we aren't already using the local APIC timer to drive the
* kernel clocks, then setup the RTC to periodically interrupt to
* drive statclock() and profclock().
*/
if (!using_lapic_timer) {
using_atrtc_timer = atrtc_setup_clock();
if (using_atrtc_timer) {
/* Enable periodic interrupts from the RTC. */
intr_add_handler("rtc", 8,
(driver_filter_t *)rtcintr, NULL, NULL,
INTR_TYPE_CLK, NULL);
atrtc_enable_intr();
} else {
profhz = hz;
if (hz < 128)
stathz = hz;
else
stathz = hz / (hz / 128);
}
}
init_TSC_tc();
}
void
cpu_startprofclock(void)
{
if (using_lapic_timer || !using_atrtc_timer)
return;
atrtc_rate(RTCSA_PROF);
psdiv = pscnt = psratio;
}
void
cpu_stopprofclock(void)
{
if (using_lapic_timer || !using_atrtc_timer)
return;
atrtc_rate(RTCSA_NOPROF);
psdiv = pscnt = 1;
}
static int
sysctl_machdep_i8254_freq(SYSCTL_HANDLER_ARGS)
{
int error;
u_int freq;
/*
* Use `i8254' instead of `timer' in external names because `timer'
* is is too generic. Should use it everywhere.
*/
freq = i8254_freq;
error = sysctl_handle_int(oidp, &freq, 0, req);
if (error == 0 && req->newptr != NULL)
set_i8254_freq(freq, hz);
return (error);
}
SYSCTL_PROC(_machdep, OID_AUTO, i8254_freq, CTLTYPE_INT | CTLFLAG_RW,
0, sizeof(u_int), sysctl_machdep_i8254_freq, "IU", "");
static unsigned
i8254_simple_get_timecount(struct timecounter *tc)
{
return (i8254_max_count - getit());
}
static unsigned
i8254_get_timecount(struct timecounter *tc)
{
u_int count;
u_int high, low;
u_int eflags;
eflags = read_eflags();
mtx_lock_spin(&clock_lock);
/* Select timer0 and latch counter value. */
outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
low = inb(TIMER_CNTR0);
high = inb(TIMER_CNTR0);
count = i8254_max_count - ((high << 8) | low);
if (count < i8254_lastcount ||
(!i8254_ticked && (clkintr_pending ||
((count < 20 || (!(eflags & PSL_I) &&
count < i8254_max_count / 2u)) &&
i8254_pending != NULL && i8254_pending(i8254_intsrc))))) {
i8254_ticked = 1;
i8254_offset += i8254_max_count;
}
i8254_lastcount = count;
count += i8254_offset;
mtx_unlock_spin(&clock_lock);
return (count);
}
#ifdef DEV_ISA
/*
* Attach to the ISA PnP descriptors for the timer
*/
static struct isa_pnp_id attimer_ids[] = {
{ 0x0001d041 /* PNP0100 */, "AT timer" },
{ 0 }
};
static int
attimer_probe(device_t dev)
{
int result;
result = ISA_PNP_PROBE(device_get_parent(dev), dev, attimer_ids);
if (result <= 0)
device_quiet(dev);
return(result);
}
static int
attimer_attach(device_t dev)
{
return(0);
}
static device_method_t attimer_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, attimer_probe),
DEVMETHOD(device_attach, attimer_attach),
DEVMETHOD(device_detach, bus_generic_detach),
DEVMETHOD(device_shutdown, bus_generic_shutdown),
DEVMETHOD(device_suspend, bus_generic_suspend),
DEVMETHOD(device_resume, bus_generic_resume),
{ 0, 0 }
};
static driver_t attimer_driver = {
"attimer",
attimer_methods,
1, /* no softc */
};
static devclass_t attimer_devclass;
DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0);
#endif /* DEV_ISA */