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/*-
* Copyright (c) 2010 Greg Ansley. 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.
*/
/*
* The SAM9 watchdog hardware can be programed only once. So we set the
* hardware watchdog to 16 s in wdt_attach and only reset it in the wdt_tick
* handler. The watchdog is halted in processor debug mode.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/watchdog.h>
#include <machine/bus.h>
#include <arm/at91/at91var.h>
#include <arm/at91/at91_wdtreg.h>
struct wdt_softc {
struct mtx sc_mtx;
device_t sc_dev;
struct resource *mem_res;
struct callout tick_ch;
eventhandler_tag sc_wet;
void *intrhand;
u_int cmd;
u_int interval;
};
static inline uint32_t
RD4(struct wdt_softc *sc, bus_size_t off)
{
return (bus_read_4(sc->mem_res, off));
}
static inline void
WR4(struct wdt_softc *sc, bus_size_t off, uint32_t val)
{
bus_write_4(sc->mem_res, off, val);
}
static int
wdt_intr(void *argp)
{
struct wdt_softc *sc = argp;
if (RD4(sc, WDT_SR) & (WDT_WDUNF | WDT_WDERR)) {
#if defined(KDB) && !defined(KDB_UNATTENDED)
kdb_backtrace();
kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout");
#else
panic("watchdog timeout");
#endif
}
return (FILTER_STRAY);
}
/* User interface, see watchdog(9) */
static void
wdt_watchdog(void *argp, u_int cmd, int *error)
{
struct wdt_softc *sc = argp;
u_int interval;
mtx_lock(&sc->sc_mtx);
*error = 0;
sc->cmd = 0;
interval = cmd & WD_INTERVAL;
if (interval > WD_TO_16SEC)
*error = EOPNOTSUPP;
else if (interval > 0)
sc->cmd = interval | WD_ACTIVE;
/* We cannot turn off our watchdog so if user
* fails to turn us on go to passive mode. */
if ((sc->cmd & WD_ACTIVE) == 0)
sc->cmd = WD_PASSIVE;
mtx_unlock(&sc->sc_mtx);
}
/* This routine is called no matter what state the user sets the
* watchdog mode to. Called at a rate that is slightly less than
* half the hardware timeout. */
static void
wdt_tick(void *argp)
{
struct wdt_softc *sc = argp;
mtx_assert(&sc->sc_mtx, MA_OWNED);
if (sc->cmd & (WD_ACTIVE | WD_PASSIVE))
WR4(sc, WDT_CR, WDT_KEY|WDT_WDRSTT);
sc->cmd &= WD_PASSIVE;
callout_reset(&sc->tick_ch, sc->interval, wdt_tick, sc);
}
static int
wdt_probe(device_t dev)
{
if (at91_is_sam9() || at91_is_sam9xe()) {
device_set_desc(dev, "WDT");
return (0);
}
return (ENXIO);
}
static int
wdt_attach(device_t dev)
{
static struct wdt_softc *sc;
struct resource *irq;
uint32_t wdt_mr;
int rid, err;
sc = device_get_softc(dev);
sc->cmd = WD_PASSIVE;
sc->sc_dev = dev;
mtx_init(&sc->sc_mtx, device_get_nameunit(dev), "at91_wdt", MTX_DEF);
callout_init_mtx(&sc->tick_ch, &sc->sc_mtx, 0);
rid = 0;
sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
if (sc->mem_res == NULL)
panic("couldn't allocate wdt register resources");
wdt_mr = RD4(sc, WDT_MR);
if ((wdt_mr & WDT_WDRSTEN) == 0)
device_printf(dev, "Watchdog disabled! (Boot ROM?)\n");
else {
#ifdef WDT_RESET
/* Rude, full reset of whole system on watch dog timeout */
WR4(sc, WDT_MR, WDT_WDDBGHLT | WDT_WDD(0xC00)|
WDT_WDRSTEN| WDT_WDV(0xFFF));
#else
/* Generate stack trace and panic on watchdog timeout*/
WR4(sc, WDT_MR, WDT_WDDBGHLT | WDT_WDD(0xC00)|
WDT_WDFIEN| WDT_WDV(0xFFF));
#endif
/*
* This may have been set by Boot ROM so register value may
* not be what we just requested since this is a write once
* register.
*/
wdt_mr = RD4(sc, WDT_MR);
if (wdt_mr & WDT_WDFIEN) {
rid = 0;
irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
RF_ACTIVE | RF_SHAREABLE);
if (!irq)
panic("could not allocate interrupt.\n");
err = bus_setup_intr(dev, irq, INTR_TYPE_CLK, wdt_intr,
NULL, sc, &sc->intrhand);
}
/* interval * hz */
sc->interval = (((wdt_mr & WDT_WDV(~0)) + 1) * WDT_DIV) /
(WDT_CLOCK/hz);
device_printf(dev, "watchdog timeout: %d seconds\n",
sc->interval / hz);
/* Slightly less than 1/2 of watchdog hardware timeout */
sc->interval = (sc->interval/2) - (sc->interval/20);
callout_reset(&sc->tick_ch, sc->interval, wdt_tick, sc);
/* Register us as a watchdog */
sc->sc_wet = EVENTHANDLER_REGISTER(watchdog_list,
wdt_watchdog, sc, 0);
}
return (0);
}
static device_method_t wdt_methods[] = {
DEVMETHOD(device_probe, wdt_probe),
DEVMETHOD(device_attach, wdt_attach),
DEVMETHOD_END
};
static driver_t wdt_driver = {
"at91_wdt",
wdt_methods,
sizeof(struct wdt_softc),
};
static devclass_t wdt_devclass;
DRIVER_MODULE(at91_wdt, atmelarm, wdt_driver, wdt_devclass, NULL, NULL);
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