/*	$OpenBSD: ichwdt.c,v 1.4 2012/10/17 22:32:01 deraadt Exp $	*/

/*
 * Copyright (c) 2004, 2005 Alexander Yurchenko <grange@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.
 */

/*
 * Intel 6300ESB ICH watchdog timer driver.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>

#include <machine/bus.h>

#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>
#include <dev/pci/pcidevs.h>

#include <dev/pci/ichreg.h>

#ifdef ICHWDT_DEBUG
#define DPRINTF(x) printf x
#else
#define DPRINTF(x)
#endif

struct ichwdt_softc {
	struct device sc_dev;

	pci_chipset_tag_t sc_pc;
	pcitag_t sc_tag;

	bus_space_tag_t sc_iot;
	bus_space_handle_t sc_ioh;

	int sc_divisor;
	int sc_period;
};

int	ichwdt_match(struct device *, void *, void *);
void	ichwdt_attach(struct device *, struct device *, void *);

int	ichwdt_cb(void *, int);

struct cfattach ichwdt_ca = {
	sizeof(struct ichwdt_softc),
	ichwdt_match,
	ichwdt_attach
};

struct cfdriver ichwdt_cd = {
	NULL, "ichwdt", DV_DULL
};

const struct pci_matchid ichwdt_devices[] = {
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_6300ESB_WDT }
};

static __inline void
ichwdt_unlock_write(struct ichwdt_softc *sc, int reg, u_int32_t val)
{
	/* Register unlocking sequence */
	bus_space_write_4(sc->sc_iot, sc->sc_ioh, ICH_WDT_RELOAD, 0x80);
	bus_space_write_4(sc->sc_iot, sc->sc_ioh, ICH_WDT_RELOAD, 0x86);

	/* Now it's possible to write to the register */
	bus_space_write_4(sc->sc_iot, sc->sc_ioh, reg, val);
}

int
ichwdt_match(struct device *parent, void *match, void *aux)
{
	return (pci_matchbyid((struct pci_attach_args *)aux, ichwdt_devices,
	    sizeof(ichwdt_devices) / sizeof(ichwdt_devices[0])));
}

void
ichwdt_attach(struct device *parent, struct device *self, void *aux)
{
	struct ichwdt_softc *sc = (struct ichwdt_softc *)self;
	struct pci_attach_args *pa = aux;
	u_int32_t reg;

	sc->sc_pc = pa->pa_pc;
	sc->sc_tag = pa->pa_tag;

	/* Map memory space */
	sc->sc_iot = pa->pa_iot;
	if (pci_mapreg_map(pa, ICH_WDT_BASE, PCI_MAPREG_TYPE_MEM, 0,
	    &sc->sc_iot, &sc->sc_ioh, NULL, NULL, 0)) {
		printf(": can't map mem space\n");
		return;
	}

	/* Read current configuration */
	reg = pci_conf_read(sc->sc_pc, sc->sc_tag, ICH_WDT_CONF);
	DPRINTF((": conf 0x%x", reg));

	/* Get clock divisor */
	sc->sc_divisor = (reg & ICH_WDT_CONF_PRE ? 32 : 32768);
	printf(": %s clock", (reg & ICH_WDT_CONF_PRE ? "1MHz" : "1kHz"));

	/* Disable interrupts since we don't use first stage timeout alarm */
	reg &= ~ICH_WDT_CONF_INT_MASK;
	reg |= ICH_WDT_CONF_INT_DIS;
	pci_conf_write(sc->sc_pc, sc->sc_tag, ICH_WDT_CONF, reg);

	/* Check for reboot on timeout */
	reg = bus_space_read_4(sc->sc_iot, sc->sc_ioh, ICH_WDT_RELOAD);
	if (reg & ICH_WDT_RELOAD_TIMEOUT) {
		printf(": reboot on timeout");

		/* Clear timeout bit */
		ichwdt_unlock_write(sc, ICH_WDT_RELOAD,
		    ICH_WDT_RELOAD_TIMEOUT);
	}

	/* Disable watchdog */
	pci_conf_write(sc->sc_pc, sc->sc_tag, ICH_WDT_LOCK, 0);
	sc->sc_period = 0;
	
	printf("\n");

	/* Register new watchdog */
	wdog_register(ichwdt_cb, sc);
}

int
ichwdt_cb(void *arg, int period)
{
	struct ichwdt_softc *sc = arg;
	int ticks;

	if (period == 0) {
		if (sc->sc_period != 0) {
			/* Disable watchdog */
			ichwdt_unlock_write(sc, ICH_WDT_RELOAD,
			    ICH_WDT_RELOAD_RLD);
			pci_conf_write(sc->sc_pc, sc->sc_tag, ICH_WDT_LOCK, 0);
			DPRINTF(("%s: disabled, conf 0x%x\n",
			    sc->sc_dev.dv_xname,
			    pci_conf_read(sc->sc_pc, sc->sc_tag,
			    ICH_WDT_LOCK)));
		}
	} else {
		/* 1000s should be enough for everyone */
		if (period > 1000)
			period = 1000;

		if (sc->sc_period != period) {
			/* Set new timeout */
			ticks = (period * 33000000) / sc->sc_divisor;
			ichwdt_unlock_write(sc, ICH_WDT_PRE1, ticks);
			ichwdt_unlock_write(sc, ICH_WDT_PRE2, 2);
			DPRINTF(("%s: timeout %ds (%d ticks)\n",
			    sc->sc_dev.dv_xname, period, ticks));
		}
		if (sc->sc_period == 0) {
			/* Enable watchdog */
			pci_conf_write(sc->sc_pc, sc->sc_tag, ICH_WDT_LOCK,
			    ICH_WDT_LOCK_ENABLED);
			DPRINTF(("%s: enabled, conf 0x%x\n",
			    sc->sc_dev.dv_xname,
			    pci_conf_read(sc->sc_pc, sc->sc_tag,
			    ICH_WDT_LOCK)));
		} else {
			/* Reset timer */
			ichwdt_unlock_write(sc, ICH_WDT_RELOAD,
			    ICH_WDT_RELOAD_RLD);
			DPRINTF(("%s: reloaded\n", sc->sc_dev.dv_xname));
		}
	}
	sc->sc_period = period;

	return (period);
}