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/* $OpenBSD: dwdog.c,v 1.1 2017/07/25 20:20:09 kettenis Exp $ */
/*
* Copyright (c) 2017 Mark kettenis <kettenis@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <machine/bus.h>
#include <machine/fdt.h>
#include <armv7/armv7/armv7_machdep.h>
#include <dev/ofw/openfirm.h>
#include <dev/ofw/fdt.h>
/* Registers */
#define WDT_CR 0x0000
#define WDT_CR_WDT_EN (1 << 0)
#define WDT_CR_RESP_MODE (1 << 1)
#define WDT_TORR 0x0004
#define WDT_CCVR 0x0008
#define WDT_CRR 0x000c
#define WDT_CRR_KICK 0x76
#define WDT_STAT 0x0010
#define WDT_EOI 0x0014
#define HREAD4(sc, reg) \
(bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
#define HWRITE4(sc, reg, val) \
bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
#define HSET4(sc, reg, bits) \
HWRITE4((sc), (reg), HREAD4((sc), (reg)) | (bits))
#define HCLR4(sc, reg, bits) \
HWRITE4((sc), (reg), HREAD4((sc), (reg)) & ~(bits))
struct dwdog_softc {
struct device sc_dev;
bus_space_tag_t sc_iot;
bus_space_handle_t sc_ioh;
};
int dwdog_match(struct device *, void *, void *);
void dwdog_attach(struct device *, struct device *, void *);
struct cfattach dwdog_ca = {
sizeof(struct dwdog_softc), dwdog_match, dwdog_attach
};
struct cfdriver dwdog_cd = {
NULL, "dwdog", DV_DULL
};
void dwdog_reset(void);
int
dwdog_match(struct device *parent, void *match, void *aux)
{
struct fdt_attach_args *faa = aux;
return OF_is_compatible(faa->fa_node, "snps,dw-wdt");
}
void
dwdog_attach(struct device *parent, struct device *self, void *aux)
{
struct dwdog_softc *sc = (struct dwdog_softc *)self;
struct fdt_attach_args *faa = aux;
if (faa->fa_nreg < 1) {
printf(": no registers\n");
return;
}
sc->sc_iot = faa->fa_iot;
if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
printf(": can't map registers\n");
}
printf("\n");
if (cpuresetfn == NULL)
cpuresetfn = dwdog_reset;
}
void
dwdog_reset(void)
{
struct dwdog_softc *sc = dwdog_cd.cd_devs[0];
/*
* Generate system reset when timer expires and select
* smallest timeout.
*/
HCLR4(sc, WDT_CR, WDT_CR_RESP_MODE | WDT_CR_WDT_EN);
HWRITE4(sc, WDT_TORR, 0);
HSET4(sc, WDT_CR, WDT_CR_WDT_EN);
/* Kick the dog! */
HWRITE4(sc, WDT_CRR, WDT_CRR_KICK);
delay(1000000);
}
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