/* $NetBSD: bcm2835_tmr.c,v 1.7 2015/07/29 14:22:49 skrll Exp $ */ /*- * Copyright (c) 2012 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Nick Hudson * * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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 __KERNEL_RCSID(0, "$NetBSD: bcm2835_tmr.c,v 1.7 2015/07/29 14:22:49 skrll Exp $"); #include #include #include #include #include #include #include #include #include #define BCM2835_STIMER_CS 0x00 #define BCM2835_STIMER_M0 __BIT(0) #define BCM2835_STIMER_M1 __BIT(1) #define BCM2835_STIMER_M2 __BIT(2) #define BCM2835_STIMER_M3 __BIT(3) #define BCM2835_STIMER_CLO 0x04 #define BCM2835_STIMER_CHI 0x08 #define BCM2835_STIMER_C0 0x0c #define BCM2835_STIMER_C1 0x10 #define BCM2835_STIMER_C2 0x14 #define BCM2835_STIMER_C3 0x18 #define BCM2835_STIMER_HZ 1000000 static const uint32_t counts_per_usec = (BCM2835_STIMER_HZ / 1000000); static uint32_t counts_per_hz = ~0; struct bcm2835tmr_softc { device_t sc_dev; bus_space_tag_t sc_iot; bus_space_handle_t sc_ioh; }; static int bcmtmr_match(device_t, cfdata_t, void *); static void bcmtmr_attach(device_t, device_t, void *); static int clockhandler(void *); static u_int bcm2835tmr_get_timecount(struct timecounter *); static struct bcm2835tmr_softc *bcm2835tmr_sc; static struct timecounter bcm2835tmr_timecounter = { .tc_get_timecount = bcm2835tmr_get_timecount, .tc_poll_pps = 0, .tc_counter_mask = ~0u, .tc_frequency = BCM2835_STIMER_HZ, .tc_name = NULL, /* set by attach */ .tc_quality = 100, .tc_priv = NULL, .tc_next = NULL, }; CFATTACH_DECL_NEW(bcmtmr_amba, sizeof(struct bcm2835tmr_softc), bcmtmr_match, bcmtmr_attach, NULL, NULL); /* ARGSUSED */ static int bcmtmr_match(device_t parent, cfdata_t match, void *aux) { struct amba_attach_args *aaa = aux; if (strcmp(aaa->aaa_name, "bcmtmr") != 0) return 0; return 1; } static void bcmtmr_attach(device_t parent, device_t self, void *aux) { struct bcm2835tmr_softc *sc = device_private(self); struct amba_attach_args *aaa = aux; aprint_naive("\n"); aprint_normal(": VC System Timer\n"); if (bcm2835tmr_sc == NULL) bcm2835tmr_sc = sc; sc->sc_dev = self; sc->sc_iot = aaa->aaa_iot; if (bus_space_map(aaa->aaa_iot, aaa->aaa_addr, BCM2835_STIMER_SIZE, 0, &sc->sc_ioh)) { aprint_error_dev(sc->sc_dev, "unable to map device\n"); return; } bcm2835tmr_timecounter.tc_name = device_xname(self); } void cpu_initclocks(void) { struct bcm2835tmr_softc *sc = bcm2835tmr_sc; void *clock_ih; uint32_t stcl; KASSERT(sc != NULL); bcm2835tmr_timecounter.tc_priv = sc; counts_per_hz = BCM2835_STIMER_HZ / hz; stcl = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); stcl += counts_per_hz; bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_C3, stcl); clock_ih = intr_establish(BCM2835_INT_TIMER3, IPL_CLOCK, IST_LEVEL, clockhandler, NULL); if (clock_ih == NULL) panic("%s: unable to register timer interrupt", __func__); tc_init(&bcm2835tmr_timecounter); } void delay(unsigned int n) { struct bcm2835tmr_softc *sc = bcm2835tmr_sc; uint32_t last, curr; uint32_t delta, usecs; KASSERT(sc != NULL); last = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); delta = usecs = 0; while (n > usecs) { curr = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); /* Check to see if the timer has wrapped around. */ if (curr < last) delta += curr + (UINT32_MAX - last); else delta += curr - last; last = curr; if (delta >= counts_per_usec) { usecs += delta / counts_per_usec; delta %= counts_per_usec; } } } /* * clockhandler: * * Handle the hardclock interrupt. */ static int clockhandler(void *arg) { struct bcm2835tmr_softc *sc = bcm2835tmr_sc; struct clockframe *frame = arg; uint32_t curr, status; status = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CS); if (!(status & BCM2835_STIMER_M3)) return 0; bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CS, BCM2835_STIMER_M3); hardclock(frame); curr = bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); curr += counts_per_hz; bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_C3, curr); return 1; } void setstatclockrate(int newhz) { } static u_int bcm2835tmr_get_timecount(struct timecounter *tc) { struct bcm2835tmr_softc *sc = tc->tc_priv; return bus_space_read_4(sc->sc_iot, sc->sc_ioh, BCM2835_STIMER_CLO); }