/* $OpenBSD: footbridge_clock.c,v 1.7 2004/09/16 21:52:46 miod Exp $ */ /* $NetBSD: footbridge_clock.c,v 1.17 2003/03/23 14:12:25 chris Exp $ */ /* * Copyright (c) 1997 Mark Brinicombe. * Copyright (c) 1997 Causality Limited. * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Mark Brinicombe * for the NetBSD Project. * 4. The name of the company nor the name of the author may be used to * endorse or promote products derived from this software without specific * prior written permission. * * 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 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. */ #include /* Include header files */ #include #include #include #include #include #include #include #include #include #include #include extern struct footbridge_softc *clock_sc; extern u_int dc21285_fclk; int clockhandler (void *); int statclockhandler (void *); static int load_timer (int, int); /* * Statistics clock variance, in usec. Variance must be a * power of two. Since this gives us an even number, not an odd number, * we discard one case and compensate. That is, a variance of 1024 would * give us offsets in [0..1023]. Instead, we take offsets in [1..1023]. * This is symmetric about the point 512, or statvar/2, and thus averages * to that value (assuming uniform random numbers). */ const int statvar = 1024; int statmin; /* minimum stat clock count in ticks */ int statcountperusec; /* number of ticks per usec at current stathz */ int statprev; /* last value of we set statclock to */ #if 0 static int clockmatch (struct device *parent, struct cfdata *cf, void *aux); static void clockattach (struct device *parent, struct device *self, void *aux); CFATTACH_DECL(footbridge_clock, sizeof(struct clock_softc), clockmatch, clockattach, NULL, NULL); /* * int clockmatch(struct device *parent, void *match, void *aux) * * Just return ok for this if it is device 0 */ static int clockmatch(parent, cf, aux) struct device *parent; struct cfdata *cf; void *aux; { union footbridge_attach_args *fba = aux; if (strcmp(fba->fba_ca.ca_name, "clk") == 0) return(1); return(0); } /* * void clockattach(struct device *parent, struct device *dev, void *aux) * */ static void clockattach(parent, self, aux) struct device *parent; struct device *self; void *aux; { struct clock_softc *sc = (struct clock_softc *)self; union footbridge_attach_args *fba = aux; sc->sc_iot = fba->fba_ca.ca_iot; sc->sc_ioh = fba->fba_ca.ca_ioh; clock_sc = sc; /* Cannot do anything until cpu_initclocks() has been called */ printf("\n"); } #endif /* * int clockhandler(struct clockframe *frame) * * Function called by timer 1 interrupts. * This just clears the interrupt condition and calls hardclock(). */ int clockhandler(aframe) void *aframe; { struct clockframe *frame = aframe; bus_space_write_4(clock_sc->sc_iot, clock_sc->sc_ioh, TIMER_1_CLEAR, 0); hardclock(frame); return(-1); /* Pass the interrupt on down the chain */ } /* * int statclockhandler(struct clockframe *frame) * * Function called by timer 2 interrupts. * This just clears the interrupt condition and calls statclock(). */ int statclockhandler(aframe) void *aframe; { struct clockframe *frame = aframe; int newint, r; int currentclock ; /* start the clock off again */ bus_space_write_4(clock_sc->sc_iot, clock_sc->sc_ioh, TIMER_2_CLEAR, 0); do { r = random() & (statvar-1); } while (r == 0); newint = statmin + (r * statcountperusec); /* fetch the current count */ currentclock = bus_space_read_4(clock_sc->sc_iot, clock_sc->sc_ioh, TIMER_2_VALUE); /* * work out how much time has run, add another usec for time spent * here */ r = ((statprev - currentclock) + statcountperusec); if (r < newint) { newint -= r; r = 0; } else printf("statclockhandler: Statclock overrun\n"); /* * update the clock to the new counter, this reloads the existing * timer */ bus_space_write_4(clock_sc->sc_iot, clock_sc->sc_ioh, TIMER_2_LOAD, newint); statprev = newint; statclock(frame); if (r) /* * We've completely overrun the previous interval, * make sure we report the correct number of ticks. */ statclock(frame); return(-1); /* Pass the interrupt on down the chain */ } static int load_timer(base, hz) int base; int hz; { unsigned int timer_count; int control; timer_count = dc21285_fclk / hz; if (timer_count > TIMER_MAX_VAL * 16) { control = TIMER_FCLK_256; timer_count >>= 8; } else if (timer_count > TIMER_MAX_VAL) { control = TIMER_FCLK_16; timer_count >>= 4; } else control = TIMER_FCLK; control |= (TIMER_ENABLE | TIMER_MODE_PERIODIC); bus_space_write_4(clock_sc->sc_iot, clock_sc->sc_ioh, base + TIMER_LOAD, timer_count); bus_space_write_4(clock_sc->sc_iot, clock_sc->sc_ioh, base + TIMER_CONTROL, control); bus_space_write_4(clock_sc->sc_iot, clock_sc->sc_ioh, base + TIMER_CLEAR, 0); return(timer_count); } /* * void setstatclockrate(int hz) * * Set the stat clock rate. The stat clock uses timer2 */ void setstatclockrate(hz) int hz; { int statint; int countpersecond; int statvarticks; /* statint == num in counter to drop by desired hz */ statint = statprev = clock_sc->sc_statclock_count = load_timer(TIMER_2_BASE, hz); /* Get the total ticks a second */ countpersecond = statint * hz; /* now work out how many ticks per usec */ statcountperusec = countpersecond / 1000000; /* calculate a variance range of statvar */ statvarticks = statcountperusec * statvar; /* minimum is statint - 50% of variant */ statmin = statint - (statvarticks / 2); } /* * void cpu_initclocks(void) * * Initialise the clocks. * * Timer 1 is used for the main system clock (hardclock) * Timer 2 is used for the statistics clock (statclock) */ void cpu_initclocks() { /* stathz and profhz should be set to something, we have the timer */ if (stathz == 0) stathz = 128; if (profhz == 0) profhz = stathz * 8; /* Report the clock frequencies */ printf("clock: hz %d stathz %d profhz %d\n", hz, stathz, profhz); /* Setup timer 1 and claim interrupt */ clock_sc->sc_clock_count = load_timer(TIMER_1_BASE, hz); /* * Use ticks per 256us for accuracy since ticks per us is often * fractional e.g. @ 66MHz */ clock_sc->sc_clock_ticks_per_256us = ((((clock_sc->sc_clock_count * hz) / 1000) * 256) / 1000); clock_sc->sc_clockintr = footbridge_intr_claim(IRQ_TIMER_1, IPL_CLOCK, "clock", clockhandler, 0); if (clock_sc->sc_clockintr == NULL) panic("%s: Cannot install timer 1 interrupt handler", clock_sc->sc_dev.dv_xname); /* If stathz is non-zero then setup the stat clock */ if (stathz) { /* Setup timer 2 and claim interrupt */ setstatclockrate(stathz); clock_sc->sc_statclockintr = footbridge_intr_claim(IRQ_TIMER_2, IPL_STATCLOCK, "stat", statclockhandler, 0); if (clock_sc->sc_statclockintr == NULL) panic("%s: Cannot install timer 2 interrupt handler", clock_sc->sc_dev.dv_xname); } } /* * void microtime(struct timeval *tvp) * * Fill in the specified timeval struct with the current time * accurate to the microsecond. */ void microtime(tvp) struct timeval *tvp; { int s; int tm; int deltatm; static struct timeval oldtv; if (clock_sc == NULL || clock_sc->sc_clock_count == 0) return; s = splhigh(); tm = bus_space_read_4(clock_sc->sc_iot, clock_sc->sc_ioh, TIMER_1_VALUE); deltatm = clock_sc->sc_clock_count - tm; #ifdef DIAGNOSTIC if (deltatm < 0) panic("opps deltatm < 0 tm=%d deltatm=%d", tm, deltatm); #endif /* Fill in the timeval struct */ *tvp = time; tvp->tv_usec += ((deltatm << 8) / clock_sc->sc_clock_ticks_per_256us); /* Make sure the micro seconds don't overflow. */ while (tvp->tv_usec >= 1000000) { tvp->tv_usec -= 1000000; ++tvp->tv_sec; } /* Make sure the time has advanced. */ if (tvp->tv_sec == oldtv.tv_sec && tvp->tv_usec <= oldtv.tv_usec) { tvp->tv_usec = oldtv.tv_usec + 1; if (tvp->tv_usec >= 1000000) { tvp->tv_usec -= 1000000; ++tvp->tv_sec; } } oldtv = *tvp; (void)splx(s); } /* * Use a timer to track microseconds, if the footbridge hasn't been setup we * rely on an estimated loop, however footbridge is attached very early on. */ static int delay_clock_count = 0; static int delay_count_per_usec = 0; void calibrate_delay(void) { delay_clock_count = load_timer(TIMER_3_BASE, 100); delay_count_per_usec = delay_clock_count/10000; #ifdef VERBOSE_DELAY_CALIBRATION printf("delay calibration: delay_cc = %d, delay_c/us=%d\n", delay_clock_count, delay_count_per_usec); printf("0.."); delay(1000000); printf("1.."); delay(1000000); printf("2.."); delay(1000000); printf("3.."); delay(1000000); printf("4.."); delay(1000000); printf("5.."); delay(1000000); printf("6.."); delay(1000000); printf("7.."); delay(1000000); printf("8.."); delay(1000000); printf("9.."); delay(1000000); printf("10\n"); #endif } int delaycount = 25000; void delay(n) u_int n; { volatile u_int i; uint32_t cur, last, delta, usecs; if (n == 0) return; /* * not calibrated the timer yet, so try to live with this horrible * loop! */ if (delay_clock_count == 0) { while (n-- > 0) { for (i = delaycount; --i;); } return; } /* * read the current value (do not reset it as delay is reentrant) */ last = bus_space_read_4(clock_sc->sc_iot, clock_sc->sc_ioh, TIMER_3_VALUE); delta = usecs = 0; while (n > usecs) { cur = bus_space_read_4(clock_sc->sc_iot, clock_sc->sc_ioh, TIMER_3_VALUE); if (last < cur) /* timer has wrapped */ delta += ((delay_clock_count - cur) + last); else delta += (last - cur); if (cur == 0) { /* * reset the timer, note that if something blocks us for more * than 1/100s we may delay for too long, but I believe that * is fairly unlikely. */ bus_space_write_4(clock_sc->sc_iot, clock_sc->sc_ioh, TIMER_3_CLEAR, 0); } last = cur; if (delta >= delay_count_per_usec) { usecs += delta / delay_count_per_usec; delta %= delay_count_per_usec; } } } /* End of footbridge_clock.c */