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freebsd-nq/sys/arm/broadcom/bcm2835/bcm2835_systimer.c
Emmanuel Vadot 0c051204d7 RPI-B: Add support for MULTIDELAY 
100 cycles per us seems accurate enough, at least it's better than the 200 value
that was used before.

Reviewed by:	andrew, imp
Differential Revision:	https://reviews.freebsd.org/D8062
2016-09-29 06:49:59 +00:00

314 lines
8.1 KiB
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/*
* Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
* Copyright (c) 2012 Damjan Marion <dmarion@freebsd.org>
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/rman.h>
#include <sys/timeet.h>
#include <sys/timetc.h>
#include <sys/watchdog.h>
#include <machine/bus.h>
#include <machine/cpu.h>
#include <machine/intr.h>
#include <machine/machdep.h>
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <machine/bus.h>
#define BCM2835_NUM_TIMERS 4
#define DEFAULT_TIMER 3
#define DEFAULT_TIMER_NAME "BCM2835-3"
#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 delay_func bcm_systimer_delay;
static struct timecounter bcm_systimer_tc = {
.tc_name = DEFAULT_TIMER_NAME,
.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)
{
if (bcm_systimer_sc == NULL)
return (0);
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 = DEFAULT_TIMER_NAME;
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;
if (device_get_unit(dev) == 0)
arm_set_delay(bcm_systimer_delay, 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);
static void
bcm_systimer_delay(int usec, void *arg)
{
struct bcm_systimer_softc *sc;
int32_t counts;
uint32_t first, last;
sc = (struct bcm_systimer_softc *) arg;
/* 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;
}
}
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