310 lines
8.0 KiB
C
310 lines
8.0 KiB
C
/*
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* Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
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* Copyright (c) 2012 Damjan Marion <dmarion@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/malloc.h>
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#include <sys/rman.h>
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#include <sys/timeet.h>
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#include <sys/timetc.h>
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#include <sys/watchdog.h>
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#include <machine/bus.h>
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#include <machine/cpu.h>
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#include <machine/intr.h>
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#include <dev/fdt/fdt_common.h>
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#include <dev/ofw/openfirm.h>
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#include <machine/bus.h>
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#define BCM2835_NUM_TIMERS 4
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#define DEFAULT_TIMER 3
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#define DEFAULT_TIMER_NAME "BCM2835-3"
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#define DEFAULT_FREQUENCY 1000000
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#define MIN_PERIOD 5LLU
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#define SYSTIMER_CS 0x00
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#define SYSTIMER_CLO 0x04
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#define SYSTIMER_CHI 0x08
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#define SYSTIMER_C0 0x0C
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#define SYSTIMER_C1 0x10
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#define SYSTIMER_C2 0x14
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#define SYSTIMER_C3 0x18
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struct systimer {
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int index;
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bool enabled;
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struct eventtimer et;
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};
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struct bcm_systimer_softc {
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struct resource* mem_res;
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struct resource* irq_res[BCM2835_NUM_TIMERS];
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void* intr_hl[BCM2835_NUM_TIMERS];
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uint32_t sysclk_freq;
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bus_space_tag_t bst;
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bus_space_handle_t bsh;
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struct systimer st[BCM2835_NUM_TIMERS];
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};
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static struct resource_spec bcm_systimer_irq_spec[] = {
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{ SYS_RES_IRQ, 0, RF_ACTIVE },
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{ SYS_RES_IRQ, 1, RF_ACTIVE },
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{ SYS_RES_IRQ, 2, RF_ACTIVE },
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{ SYS_RES_IRQ, 3, RF_ACTIVE },
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{ -1, 0, 0 }
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};
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static struct bcm_systimer_softc *bcm_systimer_sc = NULL;
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/* Read/Write macros for Timer used as timecounter */
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#define bcm_systimer_tc_read_4(reg) \
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bus_space_read_4(bcm_systimer_sc->bst, \
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bcm_systimer_sc->bsh, reg)
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#define bcm_systimer_tc_write_4(reg, val) \
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bus_space_write_4(bcm_systimer_sc->bst, \
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bcm_systimer_sc->bsh, reg, val)
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static unsigned bcm_systimer_tc_get_timecount(struct timecounter *);
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static struct timecounter bcm_systimer_tc = {
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.tc_name = DEFAULT_TIMER_NAME,
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.tc_get_timecount = bcm_systimer_tc_get_timecount,
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.tc_poll_pps = NULL,
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.tc_counter_mask = ~0u,
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.tc_frequency = 0,
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.tc_quality = 1000,
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};
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static unsigned
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bcm_systimer_tc_get_timecount(struct timecounter *tc)
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{
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return bcm_systimer_tc_read_4(SYSTIMER_CLO);
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}
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static int
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bcm_systimer_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
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{
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struct systimer *st = et->et_priv;
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uint32_t clo, clo1;
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uint32_t count;
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register_t s;
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if (first != 0) {
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count = ((uint32_t)et->et_frequency * first) >> 32;
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s = intr_disable();
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clo = bcm_systimer_tc_read_4(SYSTIMER_CLO);
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restart:
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clo += count;
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/*
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* Clear pending interrupts
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*/
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bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
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bcm_systimer_tc_write_4(SYSTIMER_C0 + st->index*4, clo);
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clo1 = bcm_systimer_tc_read_4(SYSTIMER_CLO);
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if ((int32_t)(clo1 - clo) >= 0) {
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count *= 2;
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clo = clo1;
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goto restart;
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}
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st->enabled = 1;
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intr_restore(s);
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return (0);
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}
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return (EINVAL);
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}
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static int
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bcm_systimer_stop(struct eventtimer *et)
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{
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struct systimer *st = et->et_priv;
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st->enabled = 0;
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return (0);
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}
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static int
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bcm_systimer_intr(void *arg)
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{
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struct systimer *st = (struct systimer *)arg;
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uint32_t cs;
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cs = bcm_systimer_tc_read_4(SYSTIMER_CS);
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if ((cs & (1 << st->index)) == 0)
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return (FILTER_STRAY);
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/* ACK interrupt */
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bcm_systimer_tc_write_4(SYSTIMER_CS, (1 << st->index));
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if (st->enabled) {
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if (st->et.et_active) {
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st->et.et_event_cb(&st->et, st->et.et_arg);
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}
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}
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return (FILTER_HANDLED);
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}
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static int
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bcm_systimer_probe(device_t dev)
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{
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if (!ofw_bus_status_okay(dev))
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return (ENXIO);
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if (ofw_bus_is_compatible(dev, "broadcom,bcm2835-system-timer")) {
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device_set_desc(dev, "BCM2835 System Timer");
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return (BUS_PROBE_DEFAULT);
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}
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return (ENXIO);
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}
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static int
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bcm_systimer_attach(device_t dev)
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{
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struct bcm_systimer_softc *sc = device_get_softc(dev);
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int err;
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int rid = 0;
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if (bcm_systimer_sc != NULL)
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return (EINVAL);
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sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
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if (sc->mem_res == NULL) {
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device_printf(dev, "could not allocate memory resource\n");
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return (ENXIO);
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}
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sc->bst = rman_get_bustag(sc->mem_res);
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sc->bsh = rman_get_bushandle(sc->mem_res);
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/* Request the IRQ resources */
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err = bus_alloc_resources(dev, bcm_systimer_irq_spec,
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sc->irq_res);
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if (err) {
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device_printf(dev, "Error: could not allocate irq resources\n");
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return (ENXIO);
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}
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/* TODO: get frequency from FDT */
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sc->sysclk_freq = DEFAULT_FREQUENCY;
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/* Setup and enable the timer */
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if (bus_setup_intr(dev, sc->irq_res[DEFAULT_TIMER], INTR_TYPE_CLK,
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bcm_systimer_intr, NULL, &sc->st[DEFAULT_TIMER],
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&sc->intr_hl[DEFAULT_TIMER]) != 0) {
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bus_release_resources(dev, bcm_systimer_irq_spec,
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sc->irq_res);
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device_printf(dev, "Unable to setup the clock irq handler.\n");
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return (ENXIO);
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}
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sc->st[DEFAULT_TIMER].index = DEFAULT_TIMER;
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sc->st[DEFAULT_TIMER].enabled = 0;
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sc->st[DEFAULT_TIMER].et.et_name = DEFAULT_TIMER_NAME;
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sc->st[DEFAULT_TIMER].et.et_flags = ET_FLAGS_ONESHOT;
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sc->st[DEFAULT_TIMER].et.et_quality = 1000;
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sc->st[DEFAULT_TIMER].et.et_frequency = sc->sysclk_freq;
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sc->st[DEFAULT_TIMER].et.et_min_period =
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(MIN_PERIOD << 32) / sc->st[DEFAULT_TIMER].et.et_frequency + 1;
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sc->st[DEFAULT_TIMER].et.et_max_period =
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(0x7ffffffeLLU << 32) / sc->st[DEFAULT_TIMER].et.et_frequency;
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sc->st[DEFAULT_TIMER].et.et_start = bcm_systimer_start;
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sc->st[DEFAULT_TIMER].et.et_stop = bcm_systimer_stop;
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sc->st[DEFAULT_TIMER].et.et_priv = &sc->st[DEFAULT_TIMER];
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et_register(&sc->st[DEFAULT_TIMER].et);
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bcm_systimer_sc = sc;
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bcm_systimer_tc.tc_frequency = DEFAULT_FREQUENCY;
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tc_init(&bcm_systimer_tc);
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return (0);
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}
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static device_method_t bcm_systimer_methods[] = {
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DEVMETHOD(device_probe, bcm_systimer_probe),
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DEVMETHOD(device_attach, bcm_systimer_attach),
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{ 0, 0 }
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};
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static driver_t bcm_systimer_driver = {
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"systimer",
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bcm_systimer_methods,
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sizeof(struct bcm_systimer_softc),
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};
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static devclass_t bcm_systimer_devclass;
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DRIVER_MODULE(bcm_systimer, simplebus, bcm_systimer_driver, bcm_systimer_devclass, 0, 0);
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void
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DELAY(int usec)
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{
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int32_t counts;
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uint32_t first, last;
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if (bcm_systimer_sc == NULL) {
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for (; usec > 0; usec--)
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for (counts = 200; counts > 0; counts--)
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/* Prevent gcc from optimizing out the loop */
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cpufunc_nullop();
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return;
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}
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/* Get the number of times to count */
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counts = usec * (bcm_systimer_tc.tc_frequency / 1000000) + 1;
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first = bcm_systimer_tc_read_4(SYSTIMER_CLO);
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while (counts > 0) {
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last = bcm_systimer_tc_read_4(SYSTIMER_CLO);
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if (last == first)
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continue;
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if (last>first) {
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counts -= (int32_t)(last - first);
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} else {
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counts -= (int32_t)((0xFFFFFFFF - first) + last);
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}
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first = last;
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}
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}
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