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/* $OpenBSD: imxdog.c,v 1.4 2022/04/06 18:59:28 naddy Exp $ */
/*
* Copyright (c) 2012-2013,2021 Patrick Wildt <patrick@blueri.se>
*
* 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 <sys/timeout.h>
#include <machine/bus.h>
#include <machine/fdt.h>
#include <dev/ofw/openfirm.h>
#include <dev/ofw/fdt.h>
extern void (*cpuresetfn)(void);
/* registers */
#define WCR 0x00
#define WCR_WDE (1 << 2)
#define WCR_WT_SEC(x) (((x) * 2 - 1) << 8)
#define WCR_WT_MASK (0xff << 8)
#define WSR 0x02
#define WRSR 0x04
#define WICR 0x06
#define WMCR 0x08
#define WDOG_TIMEOUT_CALLBACK 60
#define WDOG_MAX_TIMEOUT_SEC 128
struct imxdog_softc {
struct device sc_dev;
bus_space_tag_t sc_iot;
bus_space_handle_t sc_ioh;
struct timeout sc_tmo;
};
struct imxdog_softc *imxdog_sc;
int imxdog_match(struct device *, void *, void *);
void imxdog_attach(struct device *, struct device *, void *);
void imxdog_reset(void);
void imxdog_timeout(void *);
const struct cfattach imxdog_ca = {
sizeof (struct imxdog_softc), imxdog_match, imxdog_attach
};
struct cfdriver imxdog_cd = {
NULL, "imxdog", DV_DULL
};
int
imxdog_match(struct device *parent, void *match, void *aux)
{
struct fdt_attach_args *faa = aux;
return OF_is_compatible(faa->fa_node, "fsl,imx21-wdt");
}
void
imxdog_attach(struct device *parent, struct device *self, void *aux)
{
struct fdt_attach_args *faa = aux;
struct imxdog_softc *sc = (struct imxdog_softc *) self;
uint16_t reg;
if (faa->fa_nreg < 1)
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))
panic("imxdog_attach: bus_space_map failed!");
printf("\n");
timeout_set(&sc->sc_tmo, imxdog_timeout, sc);
/* Adjust timeout to maximum seconds */
reg = bus_space_read_2(sc->sc_iot, sc->sc_ioh, WCR);
reg &= ~WCR_WT_MASK;
reg |= WCR_WT_SEC(WDOG_MAX_TIMEOUT_SEC);
bus_space_write_2(sc->sc_iot, sc->sc_ioh, WCR, reg);
/* Watchdog cannot be disabled, ping the watchdog if enabled */
if (bus_space_read_2(sc->sc_iot, sc->sc_ioh, WCR) & WCR_WDE)
imxdog_timeout(sc);
imxdog_sc = sc;
if (cpuresetfn == NULL)
cpuresetfn = imxdog_reset;
}
void
imxdog_reset(void)
{
struct imxdog_softc *sc = imxdog_sc;
if (sc == NULL)
return;
/* disable watchdog and set timeout to 0 */
bus_space_write_2(sc->sc_iot, sc->sc_ioh, WCR, 0);
/* sequence to reset timeout counter */
bus_space_write_2(sc->sc_iot, sc->sc_ioh, WSR, 0x5555);
bus_space_write_2(sc->sc_iot, sc->sc_ioh, WSR, 0xaaaa);
/* enable watchdog */
bus_space_write_2(sc->sc_iot, sc->sc_ioh, WCR, 1);
/* errata TKT039676 */
bus_space_write_2(sc->sc_iot, sc->sc_ioh, WCR, 1);
delay(100000);
}
void
imxdog_timeout(void *args)
{
struct imxdog_softc *sc = args;
/* Reload timeout counter */
bus_space_write_2(sc->sc_iot, sc->sc_ioh, WSR, 0x5555);
bus_space_write_2(sc->sc_iot, sc->sc_ioh, WSR, 0xaaaa);
/* Schedule reload to trigger before counter runs out */
timeout_add_sec(&sc->sc_tmo, WDOG_TIMEOUT_CALLBACK);
}
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