/* * Copyright (c) 2012 Oleksandr Tymoshenko * Copyright (c) 2012 Damjan Marion * 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 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 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define BCM2835_NUM_TIMERS 4 #define DEFAULT_TIMER 3 #define DEFAULT_FREQUENCY 1000000 #define MIN_PERIOD 5LLU #define SYSTIMER_CS 0x00 #define SYSTIMER_CLO 0x04 #define SYSTIMER_CHI 0x08 #define SYSTIMER_C0 0x0C #define SYSTIMER_C1 0x10 #define SYSTIMER_C2 0x14 #define SYSTIMER_C3 0x18 struct systimer { int index; bool enabled; struct eventtimer et; }; struct bcm_systimer_softc { struct resource* mem_res; struct resource* irq_res[BCM2835_NUM_TIMERS]; void* intr_hl[BCM2835_NUM_TIMERS]; uint32_t sysclk_freq; bus_space_tag_t bst; bus_space_handle_t bsh; struct systimer st[BCM2835_NUM_TIMERS]; }; static struct resource_spec bcm_systimer_irq_spec[] = { { SYS_RES_IRQ, 0, RF_ACTIVE }, { SYS_RES_IRQ, 1, RF_ACTIVE }, { SYS_RES_IRQ, 2, RF_ACTIVE }, { SYS_RES_IRQ, 3, RF_ACTIVE }, { -1, 0, 0 } }; static struct bcm_systimer_softc *bcm_systimer_sc = NULL; /* Read/Write macros for Timer used as timecounter */ #define bcm_systimer_tc_read_4(reg) \ bus_space_read_4(bcm_systimer_sc->bst, \ bcm_systimer_sc->bsh, reg) #define bcm_systimer_tc_write_4(reg, val) \ bus_space_write_4(bcm_systimer_sc->bst, \ bcm_systimer_sc->bsh, reg, val) static unsigned bcm_systimer_tc_get_timecount(struct timecounter *); static struct timecounter bcm_systimer_tc = { .tc_name = "BCM2835 Timecounter", .tc_get_timecount = bcm_systimer_tc_get_timecount, .tc_poll_pps = NULL, .tc_counter_mask = ~0u, .tc_frequency = 0, .tc_quality = 1000, }; static unsigned bcm_systimer_tc_get_timecount(struct timecounter *tc) { return bcm_systimer_tc_read_4(SYSTIMER_CLO); } static int bcm_systimer_start(struct eventtimer *et, sbintime_t first, sbintime_t period) { struct systimer *st = et->et_priv; uint32_t clo, clo1; uint32_t count; register_t s; if (first != 0) { count = ((uint32_t)et->et_frequency * first) >> 32; s = intr_disable(); clo = bcm_systimer_tc_read_4(SYSTIMER_CLO); restart: clo += count; /* * Clear pending interrupts */ bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index)); bcm_systimer_tc_write_4(SYSTIMER_C0 + st->index*4, clo); clo1 = bcm_systimer_tc_read_4(SYSTIMER_CLO); if ((int32_t)(clo1 - clo) >= 0) { count *= 2; clo = clo1; goto restart; } st->enabled = 1; intr_restore(s); return (0); } return (EINVAL); } static int bcm_systimer_stop(struct eventtimer *et) { struct systimer *st = et->et_priv; st->enabled = 0; return (0); } static int bcm_systimer_intr(void *arg) { struct systimer *st = (struct systimer *)arg; uint32_t cs; cs = bcm_systimer_tc_read_4(SYSTIMER_CS); if ((cs & (1 << st->index)) == 0) return (FILTER_STRAY); /* ACK interrupt */ bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index)); if (st->enabled) { if (st->et.et_active) { st->et.et_event_cb(&st->et, st->et.et_arg); } } return (FILTER_HANDLED); } static int bcm_systimer_probe(device_t dev) { if (!ofw_bus_status_okay(dev)) return (ENXIO); if (ofw_bus_is_compatible(dev, "broadcom,bcm2835-system-timer")) { device_set_desc(dev, "BCM2835 System Timer"); return (BUS_PROBE_DEFAULT); } return (ENXIO); } static int bcm_systimer_attach(device_t dev) { struct bcm_systimer_softc *sc = device_get_softc(dev); int err; int rid = 0; if (bcm_systimer_sc != NULL) return (EINVAL); sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE); if (sc->mem_res == NULL) { device_printf(dev, "could not allocate memory resource\n"); return (ENXIO); } sc->bst = rman_get_bustag(sc->mem_res); sc->bsh = rman_get_bushandle(sc->mem_res); /* Request the IRQ resources */ err = bus_alloc_resources(dev, bcm_systimer_irq_spec, sc->irq_res); if (err) { device_printf(dev, "Error: could not allocate irq resources\n"); return (ENXIO); } /* TODO: get frequency from FDT */ sc->sysclk_freq = DEFAULT_FREQUENCY; /* Setup and enable the timer */ if (bus_setup_intr(dev, sc->irq_res[DEFAULT_TIMER], INTR_TYPE_CLK, bcm_systimer_intr, NULL, &sc->st[DEFAULT_TIMER], &sc->intr_hl[DEFAULT_TIMER]) != 0) { bus_release_resources(dev, bcm_systimer_irq_spec, sc->irq_res); device_printf(dev, "Unable to setup the clock irq handler.\n"); return (ENXIO); } sc->st[DEFAULT_TIMER].index = DEFAULT_TIMER; sc->st[DEFAULT_TIMER].enabled = 0; sc->st[DEFAULT_TIMER].et.et_name = malloc(64, M_DEVBUF, M_NOWAIT | M_ZERO); sprintf(sc->st[DEFAULT_TIMER].et.et_name, "BCM2835 Event Timer %d", DEFAULT_TIMER); sc->st[DEFAULT_TIMER].et.et_flags = ET_FLAGS_ONESHOT; sc->st[DEFAULT_TIMER].et.et_quality = 1000; sc->st[DEFAULT_TIMER].et.et_frequency = sc->sysclk_freq; sc->st[DEFAULT_TIMER].et.et_min_period = (MIN_PERIOD << 32) / sc->st[DEFAULT_TIMER].et.et_frequency + 1; sc->st[DEFAULT_TIMER].et.et_max_period = (0x7ffffffeLLU << 32) / sc->st[DEFAULT_TIMER].et.et_frequency; sc->st[DEFAULT_TIMER].et.et_start = bcm_systimer_start; sc->st[DEFAULT_TIMER].et.et_stop = bcm_systimer_stop; sc->st[DEFAULT_TIMER].et.et_priv = &sc->st[DEFAULT_TIMER]; et_register(&sc->st[DEFAULT_TIMER].et); bcm_systimer_sc = sc; bcm_systimer_tc.tc_frequency = DEFAULT_FREQUENCY; tc_init(&bcm_systimer_tc); return (0); } static device_method_t bcm_systimer_methods[] = { DEVMETHOD(device_probe, bcm_systimer_probe), DEVMETHOD(device_attach, bcm_systimer_attach), { 0, 0 } }; static driver_t bcm_systimer_driver = { "systimer", bcm_systimer_methods, sizeof(struct bcm_systimer_softc), }; static devclass_t bcm_systimer_devclass; DRIVER_MODULE(bcm_systimer, simplebus, bcm_systimer_driver, bcm_systimer_devclass, 0, 0); void DELAY(int usec) { int32_t counts; uint32_t first, last; if (bcm_systimer_sc == NULL) { for (; usec > 0; usec--) for (counts = 200; counts > 0; counts--) /* Prevent gcc from optimizing out the loop */ cpufunc_nullop(); return; } /* Get the number of times to count */ counts = usec * (bcm_systimer_tc.tc_frequency / 1000000) + 1; first = bcm_systimer_tc_read_4(SYSTIMER_CLO); while (counts > 0) { last = bcm_systimer_tc_read_4(SYSTIMER_CLO); if (last == first) continue; if (last>first) { counts -= (int32_t)(last - first); } else { counts -= (int32_t)((0xFFFFFFFF - first) + last); } first = last; } }