freebsd-skq/sys/arm/at91/at91_st.c
Pedro F. Giffuni af3dc4a7ca sys/arm: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-27 15:04:10 +00:00

315 lines
7.5 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2005 Olivier Houchard. 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 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 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/kernel.h>
#include <sys/module.h>
#include <sys/time.h>
#include <sys/bus.h>
#include <sys/resource.h>
#include <sys/rman.h>
#include <sys/timetc.h>
#include <sys/watchdog.h>
#include <machine/bus.h>
#include <machine/cpu.h>
#include <machine/resource.h>
#include <machine/frame.h>
#include <machine/intr.h>
#include <arm/at91/at91var.h>
#include <arm/at91/at91_streg.h>
#include <arm/at91/at91rm92reg.h>
static struct at91_st_softc {
struct resource * sc_irq_res;
struct resource * sc_mem_res;
void * sc_intrhand;
eventhandler_tag sc_wet; /* watchdog event handler tag */
} *timer_softc;
static inline uint32_t
RD4(bus_size_t off)
{
if (timer_softc == NULL) {
uint32_t *p = (uint32_t *)(AT91_BASE + AT91RM92_ST_BASE + off);
return *p;
}
return (bus_read_4(timer_softc->sc_mem_res, off));
}
static inline void
WR4(bus_size_t off, uint32_t val)
{
if (timer_softc == NULL) {
uint32_t *p = (uint32_t *)(AT91_BASE + AT91RM92_ST_BASE + off);
*p = val;
}
else
bus_write_4(timer_softc->sc_mem_res, off, val);
}
static void at91_st_watchdog(void *, u_int, int *);
static void at91_st_initclocks(device_t , struct at91_st_softc *);
static inline int
st_crtr(void)
{
int cur1, cur2;
do {
cur1 = RD4(ST_CRTR);
cur2 = RD4(ST_CRTR);
} while (cur1 != cur2);
return (cur1);
}
static unsigned at91_st_get_timecount(struct timecounter *tc);
static struct timecounter at91_st_timecounter = {
at91_st_get_timecount, /* get_timecount */
NULL, /* no poll_pps */
0xfffffu, /* counter_mask */
32768, /* frequency */
"AT91RM9200 timer", /* name */
1000 /* quality */
};
static int
clock_intr(void *arg)
{
struct trapframe *fp = arg;
/* The interrupt is shared, so we have to make sure it's for us. */
if (RD4(ST_SR) & ST_SR_PITS) {
hardclock(TRAPF_USERMODE(fp), TRAPF_PC(fp));
return (FILTER_HANDLED);
}
return (FILTER_STRAY);
}
void
at91_st_delay(int n)
{
uint32_t start, end, cur;
start = st_crtr();
n = (n * 1000) / 32768;
if (n <= 0)
n = 1;
end = (start + n) & ST_CRTR_MASK;
cur = start;
if (start > end) {
while (cur >= start || cur < end)
cur = st_crtr();
} else {
while (cur < end)
cur = st_crtr();
}
}
void
at91_st_cpu_reset(void)
{
/*
* Reset the CPU by programmig the watchdog timer to reset the
* CPU after 128 'slow' clocks, or about ~4ms. Loop until
* the reset happens for safety.
*/
WR4(ST_WDMR, ST_WDMR_RSTEN | 2);
WR4(ST_CR, ST_CR_WDRST);
while (1)
continue;
}
static int
at91_st_probe(device_t dev)
{
device_set_desc(dev, "ST");
return (0);
}
static void
at91_st_deactivate(device_t dev)
{
struct at91_st_softc *sc = timer_softc;
if (sc->sc_intrhand)
bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intrhand);
sc->sc_intrhand = NULL;
if (sc->sc_irq_res)
bus_release_resource(dev, SYS_RES_IRQ,
rman_get_rid(sc->sc_irq_res), sc->sc_irq_res);
sc->sc_irq_res = NULL;
if (sc->sc_mem_res)
bus_release_resource(dev, SYS_RES_MEMORY,
rman_get_rid(sc->sc_mem_res), sc->sc_mem_res);
sc->sc_mem_res = NULL;
}
static int
at91_st_activate(device_t dev)
{
int rid;
int err;
struct at91_st_softc *sc = timer_softc;
rid = 0;
sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
err = ENOMEM;
if (sc->sc_mem_res == NULL)
goto out;
/* Disable all interrupts */
WR4(ST_IDR, 0xffffffff);
/* The system timer shares the system irq (1) */
rid = 0;
sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
RF_ACTIVE | RF_SHAREABLE);
if (sc->sc_irq_res == NULL) {
printf("Unable to allocate irq for the system timer");
goto out;
}
err = bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_CLK, clock_intr,
NULL, NULL, &sc->sc_intrhand);
out:
if (err != 0)
at91_st_deactivate(dev);
return (err);
}
static int
at91_st_attach(device_t dev)
{
int err;
timer_softc = device_get_softc(dev);
err = at91_st_activate(dev);
if (err)
return err;
timer_softc->sc_wet = EVENTHANDLER_REGISTER(watchdog_list,
at91_st_watchdog, dev, 0);
device_printf(dev,
"watchdog registered, timeout intervall max. 64 sec\n");
at91_st_initclocks(dev, timer_softc);
return (0);
}
static device_method_t at91_st_methods[] = {
DEVMETHOD(device_probe, at91_st_probe),
DEVMETHOD(device_attach, at91_st_attach),
{0, 0},
};
static driver_t at91_st_driver = {
"at91_st",
at91_st_methods,
sizeof(struct at91_st_softc),
};
static devclass_t at91_st_devclass;
DRIVER_MODULE(at91_st, atmelarm, at91_st_driver, at91_st_devclass, 0, 0);
static unsigned
at91_st_get_timecount(struct timecounter *tc)
{
return (st_crtr());
}
/*
* t below is in a weird unit. The watchdog is set to 2^t
* nanoseconds. Since our watchdog timer can't really do that too
* well, we approximate it by assuming that the timeout interval for
* the lsb is 2^22 ns, which is 4.194ms. This is an overestimation of
* the actual time (3.906ms), but close enough for watchdogging.
* These approximations, though a violation of the spec, improve the
* performance of the application which typically specifies things as
* WD_TO_32SEC. In that last case, we'd wait 32s before the wdog
* reset. The spec says we should wait closer to 34s, but given how
* it is likely to be used, and the extremely coarse nature time
* interval, I think this is the best solution.
*/
static void
at91_st_watchdog(void *argp, u_int cmd, int *error)
{
uint32_t wdog;
int t;
t = cmd & WD_INTERVAL;
if (t >= 22 && t <= 37) {
wdog = (1 << (t - 22)) | ST_WDMR_RSTEN;
*error = 0;
} else {
wdog = 0;
}
WR4(ST_WDMR, wdog);
WR4(ST_CR, ST_CR_WDRST);
}
static void
at91_st_initclocks(device_t dev, struct at91_st_softc *sc)
{
int rel_value;
/*
* Real time counter increments every clock cycle, need to set before
* initializing clocks so that DELAY works.
*/
WR4(ST_RTMR, 1);
/* disable watchdog timer */
WR4(ST_WDMR, 0);
rel_value = 32768 / hz;
if (rel_value < 1)
rel_value = 1;
if (32768 % hz) {
device_printf(dev, "Cannot get %d Hz clock; using %dHz\n", hz,
32768 / rel_value);
hz = 32768 / rel_value;
tick = 1000000 / hz;
}
WR4(ST_PIMR, rel_value);
/* Enable PITS interrupts. */
WR4(ST_IER, ST_SR_PITS);
tc_init(&at91_st_timecounter);
}