/*- * 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 __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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DEV_ISA #include #include #endif #ifdef DEV_MCA #include #endif #ifdef KDTRACE_HOOKS #include #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; static int lapic_allclocks = 1; TUNABLE_INT("machdep.lapic_allclocks", &lapic_allclocks); 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 enum lapic_clock using_lapic_timer = LAPIC_CLOCK_NONE; /* 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 == LAPIC_CLOCK_NONE, ("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 != LAPIC_CLOCK_NONE) 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 enum lapic_clock tlsca; #endif int tasc; /* Initialize RTC. */ atrtc_start(); tasc = atrtc_setup_clock(); /* * If the atrtc successfully initialized and the users didn't force * otherwise use the LAPIC in order to cater hardclock only, otherwise * take in charge all the clock sources. */ #ifdef DEV_APIC tlsca = (lapic_allclocks == 0 && tasc != 0) ? LAPIC_CLOCK_HARDCLOCK : LAPIC_CLOCK_ALL; using_lapic_timer = lapic_setup_clock(tlsca); #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 == LAPIC_CLOCK_NONE) { 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); } /* * 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 != LAPIC_CLOCK_ALL) { using_atrtc_timer = tasc; 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 == LAPIC_CLOCK_ALL || !using_atrtc_timer) return; atrtc_rate(RTCSA_PROF); psdiv = pscnt = psratio; } void cpu_stopprofclock(void) { if (using_lapic_timer == LAPIC_CLOCK_ALL || !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 */