xref: /freebsd-11-stable/sys/dev/acpica/acpi_thermal.c

/*-
 * Copyright (c) 2000, 2001 Michael Smith
 * Copyright (c) 2000 BSDi
 * 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 THE 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 THE 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: head/sys/dev/acpica/acpi_thermal.c 135548 2004-09-21 18:39:10Z njl $");

#include "opt_acpi.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/bus.h>
#include <sys/proc.h>
#include <sys/reboot.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <sys/power.h>

#include "acpi.h"
#include <dev/acpica/acpivar.h>

/* Hooks for the ACPI CA debugging infrastructure */
#define _COMPONENT	ACPI_THERMAL
ACPI_MODULE_NAME("THERMAL")

#define TZ_ZEROC	2732
#define TZ_KELVTOC(x)	(((x) - TZ_ZEROC) / 10), (((x) - TZ_ZEROC) % 10)

#define TZ_NOTIFY_TEMPERATURE	0x80 /* Temperature changed. */
#define TZ_NOTIFY_LEVELS	0x81 /* Cooling levels changed. */
#define TZ_NOTIFY_DEVICES	0x82 /* Device lists changed. */
#define TZ_NOTIFY_CRITICAL	0xcc /* Fake notify that _CRT/_HOT reached. */

/* Check for temperature changes every 10 seconds by default */
#define TZ_POLLRATE	10

/* Make sure the reported temperature is valid for this number of polls. */
#define TZ_VALIDCHECKS	3

/* Notify the user we will be shutting down in one more poll cycle. */
#define TZ_NOTIFYCOUNT	(TZ_VALIDCHECKS - 1)

/* ACPI spec defines this */
#define TZ_NUMLEVELS	10
struct acpi_tz_zone {
    int		ac[TZ_NUMLEVELS];
    ACPI_BUFFER	al[TZ_NUMLEVELS];
    int		crt;
    int		hot;
    ACPI_BUFFER	psl;
    int		psv;
    int		tc1;
    int		tc2;
    int		tsp;
    int		tzp;
};

struct acpi_tz_softc {
    device_t			tz_dev;
    ACPI_HANDLE			tz_handle;	/*Thermal zone handle*/
    int				tz_temperature;	/*Current temperature*/
    int				tz_active;	/*Current active cooling*/
#define TZ_ACTIVE_NONE		-1
    int				tz_requested;	/*Minimum active cooling*/
    int				tz_thflags;	/*Current temp-related flags*/
#define TZ_THFLAG_NONE		0
#define TZ_THFLAG_PSV		(1<<0)
#define TZ_THFLAG_HOT		(1<<2)
#define TZ_THFLAG_CRT		(1<<3)
    int				tz_flags;
#define TZ_FLAG_NO_SCP		(1<<0)		/*No _SCP method*/
#define TZ_FLAG_GETPROFILE	(1<<1)		/*Get power_profile in timeout*/
#define TZ_FLAG_GETSETTINGS	(1<<2)		/*Get devs/setpoints*/
    struct timespec		tz_cooling_started;
					/*Current cooling starting time*/

    struct sysctl_ctx_list	tz_sysctl_ctx;
    struct sysctl_oid		*tz_sysctl_tree;
    eventhandler_tag		tz_event;

    struct acpi_tz_zone 	tz_zone;	/*Thermal zone parameters*/
    int				tz_validchecks;
};

static int	acpi_tz_probe(device_t dev);
static int	acpi_tz_attach(device_t dev);
static int	acpi_tz_establish(struct acpi_tz_softc *sc);
static void	acpi_tz_monitor(void *Context);
static void	acpi_tz_switch_cooler_off(ACPI_OBJECT *obj, void *arg);
static void	acpi_tz_switch_cooler_on(ACPI_OBJECT *obj, void *arg);
static void	acpi_tz_getparam(struct acpi_tz_softc *sc, char *node,
				 int *data);
static void	acpi_tz_sanity(struct acpi_tz_softc *sc, int *val, char *what);
static int	acpi_tz_active_sysctl(SYSCTL_HANDLER_ARGS);
static void	acpi_tz_notify_handler(ACPI_HANDLE h, UINT32 notify,
				       void *context);
static void	acpi_tz_signal(struct acpi_tz_softc *sc, int flags);
static void	acpi_tz_timeout(struct acpi_tz_softc *sc, int flags);
static void	acpi_tz_power_profile(void *arg);
static void	acpi_tz_thread(void *arg);

static device_method_t acpi_tz_methods[] = {
    /* Device interface */
    DEVMETHOD(device_probe,	acpi_tz_probe),
    DEVMETHOD(device_attach,	acpi_tz_attach),

    {0, 0}
};

static driver_t acpi_tz_driver = {
    "acpi_tz",
    acpi_tz_methods,
    sizeof(struct acpi_tz_softc),
};

static devclass_t acpi_tz_devclass;
DRIVER_MODULE(acpi_tz, acpi, acpi_tz_driver, acpi_tz_devclass, 0, 0);
MODULE_DEPEND(acpi_tz, acpi, 1, 1, 1);

static struct sysctl_ctx_list	acpi_tz_sysctl_ctx;
static struct sysctl_oid	*acpi_tz_sysctl_tree;

/* Minimum cooling run time */
static int			acpi_tz_min_runtime = 0;
static int			acpi_tz_polling_rate = TZ_POLLRATE;

/* Timezone polling thread */
static struct proc		*acpi_tz_proc;
ACPI_LOCK_DECL(thermal, "ACPI thermal zone");

static int
acpi_tz_probe(device_t dev)
{
    int		result;

    if (acpi_get_type(dev) == ACPI_TYPE_THERMAL && !acpi_disabled("thermal")) {
	device_set_desc(dev, "Thermal Zone");
	result = -10;
    } else
	result = ENXIO;
    return (result);
}

static int
acpi_tz_attach(device_t dev)
{
    struct acpi_tz_softc	*sc;
    struct acpi_softc		*acpi_sc;
    int				error;
    char			oidname[8];

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    sc = device_get_softc(dev);
    sc->tz_dev = dev;
    sc->tz_handle = acpi_get_handle(dev);
    sc->tz_requested = TZ_ACTIVE_NONE;
    sc->tz_active = TZ_ACTIVE_NONE;
    sc->tz_thflags = TZ_THFLAG_NONE;

    /*
     * Parse the current state of the thermal zone and build control
     * structures.  We don't need to worry about interference with the
     * control thread since we haven't fully attached this device yet.
     */
    if ((error = acpi_tz_establish(sc)) != 0)
	return (error);

    /*
     * Register for any Notify events sent to this zone.
     */
    AcpiInstallNotifyHandler(sc->tz_handle, ACPI_DEVICE_NOTIFY,
			     acpi_tz_notify_handler, sc);

    /*
     * Create our sysctl nodes.
     *
     * XXX we need a mechanism for adding nodes under ACPI.
     */
    if (device_get_unit(dev) == 0) {
	acpi_sc = acpi_device_get_parent_softc(dev);
	sysctl_ctx_init(&acpi_tz_sysctl_ctx);
	acpi_tz_sysctl_tree = SYSCTL_ADD_NODE(&acpi_tz_sysctl_ctx,
			      SYSCTL_CHILDREN(acpi_sc->acpi_sysctl_tree),
			      OID_AUTO, "thermal", CTLFLAG_RD, 0, "");
	SYSCTL_ADD_INT(&acpi_tz_sysctl_ctx,
		       SYSCTL_CHILDREN(acpi_tz_sysctl_tree),
		       OID_AUTO, "min_runtime", CTLFLAG_RD | CTLFLAG_RW,
		       &acpi_tz_min_runtime, 0,
		       "minimum cooling run time in sec");
	SYSCTL_ADD_INT(&acpi_tz_sysctl_ctx,
		       SYSCTL_CHILDREN(acpi_tz_sysctl_tree),
		       OID_AUTO, "polling_rate", CTLFLAG_RD | CTLFLAG_RW,
		       &acpi_tz_polling_rate, 0, "monitor polling rate");
    }
    sysctl_ctx_init(&sc->tz_sysctl_ctx);
    sprintf(oidname, "tz%d", device_get_unit(dev));
    sc->tz_sysctl_tree = SYSCTL_ADD_NODE(&sc->tz_sysctl_ctx,
					 SYSCTL_CHILDREN(acpi_tz_sysctl_tree),
					 OID_AUTO, oidname, CTLFLAG_RD, 0, "");
    SYSCTL_ADD_OPAQUE(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
		      OID_AUTO, "temperature", CTLFLAG_RD, &sc->tz_temperature,
		      sizeof(sc->tz_temperature), "IK",
		      "current thermal zone temperature");
    SYSCTL_ADD_PROC(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
		    OID_AUTO, "active", CTLTYPE_INT | CTLFLAG_RW,
		    sc, 0, acpi_tz_active_sysctl, "I", "");

    SYSCTL_ADD_INT(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
		   OID_AUTO, "thermal_flags", CTLFLAG_RD,
		   &sc->tz_thflags, 0, "thermal zone flags");
    SYSCTL_ADD_OPAQUE(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
		      OID_AUTO, "_PSV", CTLFLAG_RD, &sc->tz_zone.psv,
		      sizeof(sc->tz_zone.psv), "IK", "");
    SYSCTL_ADD_OPAQUE(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
		      OID_AUTO, "_HOT", CTLFLAG_RD, &sc->tz_zone.hot,
		      sizeof(sc->tz_zone.hot), "IK", "");
    SYSCTL_ADD_OPAQUE(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
		      OID_AUTO, "_CRT", CTLFLAG_RD, &sc->tz_zone.crt,
		      sizeof(sc->tz_zone.crt), "IK", "");
    SYSCTL_ADD_OPAQUE(&sc->tz_sysctl_ctx, SYSCTL_CHILDREN(sc->tz_sysctl_tree),
		      OID_AUTO, "_ACx", CTLFLAG_RD, &sc->tz_zone.ac,
		      sizeof(sc->tz_zone.ac), "IK", "");

    /*
     * Create our thread; we only need one, it will service all of the
     * thermal zones.  Register our power profile event handler.
     */
    sc->tz_event = EVENTHANDLER_REGISTER(power_profile_change,
	acpi_tz_power_profile, sc, 0);
    if (acpi_tz_proc == NULL) {
	error = kthread_create(acpi_tz_thread, NULL, &acpi_tz_proc,
	    RFHIGHPID, 0, "acpi_thermal");
	if (error != 0) {
	    device_printf(sc->tz_dev, "could not create thread - %d", error);
	    goto out;
	}
    }

    /*
     * Flag the event handler for a manual invocation by our timeout.
     * We defer it like this so that the rest of the subsystem has time
     * to come up.  Don't bother evaluating/printing the temperature at
     * this point; on many systems it'll be bogus until the EC is running.
     */
    sc->tz_flags |= TZ_FLAG_GETPROFILE;

out:
    if (error != 0) {
	EVENTHANDLER_DEREGISTER(power_profile_change, sc->tz_event);
	AcpiRemoveNotifyHandler(sc->tz_handle, ACPI_DEVICE_NOTIFY,
	    acpi_tz_notify_handler);
	sysctl_ctx_free(&sc->tz_sysctl_ctx);
    }
    return_VALUE (error);
}

/*
 * Parse the current state of this thermal zone and set up to use it.
 *
 * Note that we may have previous state, which will have to be discarded.
 */
static int
acpi_tz_establish(struct acpi_tz_softc *sc)
{
    ACPI_OBJECT	*obj;
    int		i;
    char	nbuf[8];

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    /* Erase any existing state. */
    for (i = 0; i < TZ_NUMLEVELS; i++)
	if (sc->tz_zone.al[i].Pointer != NULL)
	    AcpiOsFree(sc->tz_zone.al[i].Pointer);
    if (sc->tz_zone.psl.Pointer != NULL)
	AcpiOsFree(sc->tz_zone.psl.Pointer);
    bzero(&sc->tz_zone, sizeof(sc->tz_zone));

    /* Evaluate thermal zone parameters. */
    for (i = 0; i < TZ_NUMLEVELS; i++) {
	sprintf(nbuf, "_AC%d", i);
	acpi_tz_getparam(sc, nbuf, &sc->tz_zone.ac[i]);
	sprintf(nbuf, "_AL%d", i);
	sc->tz_zone.al[i].Length = ACPI_ALLOCATE_BUFFER;
	sc->tz_zone.al[i].Pointer = NULL;
	AcpiEvaluateObject(sc->tz_handle, nbuf, NULL, &sc->tz_zone.al[i]);
	obj = (ACPI_OBJECT *)sc->tz_zone.al[i].Pointer;
	if (obj != NULL) {
	    /* Should be a package containing a list of power objects */
	    if (obj->Type != ACPI_TYPE_PACKAGE) {
		device_printf(sc->tz_dev, "%s has unknown type %d, rejecting\n",
			      nbuf, obj->Type);
		return_VALUE (ENXIO);
	    }
	}
    }
    acpi_tz_getparam(sc, "_CRT", &sc->tz_zone.crt);
    acpi_tz_getparam(sc, "_HOT", &sc->tz_zone.hot);
    sc->tz_zone.psl.Length = ACPI_ALLOCATE_BUFFER;
    sc->tz_zone.psl.Pointer = NULL;
    AcpiEvaluateObject(sc->tz_handle, "_PSL", NULL, &sc->tz_zone.psl);
    acpi_tz_getparam(sc, "_PSV", &sc->tz_zone.psv);
    acpi_tz_getparam(sc, "_TC1", &sc->tz_zone.tc1);
    acpi_tz_getparam(sc, "_TC2", &sc->tz_zone.tc2);
    acpi_tz_getparam(sc, "_TSP", &sc->tz_zone.tsp);
    acpi_tz_getparam(sc, "_TZP", &sc->tz_zone.tzp);

    /*
     * Sanity-check the values we've been given.
     *
     * XXX what do we do about systems that give us the same value for
     *     more than one of these setpoints?
     */
    acpi_tz_sanity(sc, &sc->tz_zone.crt, "_CRT");
    acpi_tz_sanity(sc, &sc->tz_zone.hot, "_HOT");
    acpi_tz_sanity(sc, &sc->tz_zone.psv, "_PSV");
    for (i = 0; i < TZ_NUMLEVELS; i++)
	acpi_tz_sanity(sc, &sc->tz_zone.ac[i], "_ACx");

    return_VALUE (0);
}

static char *aclevel_string[] = {
    "NONE", "_AC0", "_AC1", "_AC2", "_AC3", "_AC4",
    "_AC5", "_AC6", "_AC7", "_AC8", "_AC9"
};

static __inline const char *
acpi_tz_aclevel_string(int active)
{
    if (active < -1 || active >= TZ_NUMLEVELS)
	return (aclevel_string[0]);

    return (aclevel_string[active + 1]);
}

/*
 * Evaluate the condition of a thermal zone, take appropriate actions.
 */
static void
acpi_tz_monitor(void *Context)
{
    struct acpi_tz_softc *sc;
    struct	timespec curtime;
    int		temp;
    int		i;
    int		newactive, newflags;
    ACPI_STATUS	status;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    sc = (struct acpi_tz_softc *)Context;

    /* Get the current temperature. */
    status = acpi_GetInteger(sc->tz_handle, "_TMP", &temp);
    if (ACPI_FAILURE(status)) {
	ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
	    "error fetching current temperature -- %s\n",
	     AcpiFormatException(status));
	/* XXX disable zone? go to max cooling? */
	return_VOID;
    }

    ACPI_DEBUG_PRINT((ACPI_DB_VALUES, "got %d.%dC\n", TZ_KELVTOC(temp)));
    sc->tz_temperature = temp;

    /*
     * Work out what we ought to be doing right now.
     *
     * Note that the _ACx levels sort from hot to cold.
     */
    newactive = TZ_ACTIVE_NONE;
    for (i = TZ_NUMLEVELS - 1; i >= 0; i--) {
	if ((sc->tz_zone.ac[i] != -1) && (temp >= sc->tz_zone.ac[i])) {
	    newactive = i;
	    if (sc->tz_active != newactive) {
		ACPI_VPRINT(sc->tz_dev,
			    acpi_device_get_parent_softc(sc->tz_dev),
			    "_AC%d: temperature %d.%d >= setpoint %d.%d\n", i,
			    TZ_KELVTOC(temp), TZ_KELVTOC(sc->tz_zone.ac[i]));
		getnanotime(&sc->tz_cooling_started);
	    }
	}
    }

    /*
     * We are going to get _ACx level down (colder side), but give a guaranteed
     * minimum cooling run time if requested.
     */
    if (acpi_tz_min_runtime > 0 && sc->tz_active != TZ_ACTIVE_NONE &&
	(newactive == TZ_ACTIVE_NONE || newactive > sc->tz_active)) {

	getnanotime(&curtime);
	timespecsub(&curtime, &sc->tz_cooling_started);
	if (curtime.tv_sec < acpi_tz_min_runtime)
	    newactive = sc->tz_active;
    }

    /* Handle user override of active mode */
    if (sc->tz_requested != TZ_ACTIVE_NONE && sc->tz_requested < newactive)
	newactive = sc->tz_requested;

    /* update temperature-related flags */
    newflags = TZ_THFLAG_NONE;
    if (sc->tz_zone.psv != -1 && temp >= sc->tz_zone.psv)
	newflags |= TZ_THFLAG_PSV;
    if (sc->tz_zone.hot != -1 && temp >= sc->tz_zone.hot)
	newflags |= TZ_THFLAG_HOT;
    if (sc->tz_zone.crt != -1 && temp >= sc->tz_zone.crt)
	newflags |= TZ_THFLAG_CRT;

    /* If the active cooling state has changed, we have to switch things. */
    if (newactive != sc->tz_active) {
	/* Turn off the cooling devices that are on, if any are */
	if (sc->tz_active != TZ_ACTIVE_NONE)
	    acpi_ForeachPackageObject(
		(ACPI_OBJECT *)sc->tz_zone.al[sc->tz_active].Pointer,
		acpi_tz_switch_cooler_off, sc);

	/* Turn on cooling devices that are required, if any are */
	if (newactive != TZ_ACTIVE_NONE) {
	    acpi_ForeachPackageObject(
		(ACPI_OBJECT *)sc->tz_zone.al[newactive].Pointer,
		acpi_tz_switch_cooler_on, sc);
	}
	ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
		    "switched from %s to %s: %d.%dC\n",
		    acpi_tz_aclevel_string(sc->tz_active),
		    acpi_tz_aclevel_string(newactive), TZ_KELVTOC(temp));
	sc->tz_active = newactive;
    }

    /* XXX (de)activate any passive cooling that may be required. */

    /*
     * If the temperature is at _HOT or _CRT, increment our event count.
     * If it has occurred enough times, shutdown the system.  This is
     * needed because some systems will report an invalid high temperature
     * for one poll cycle.  It is suspected this is due to the embedded
     * controller timing out.  A typical value is 138C for one cycle on
     * a system that is otherwise 65C.
     *
     * If we're almost at that threshold, notify the user through devd(8).
     */
    if ((newflags & (TZ_THFLAG_HOT | TZ_THFLAG_CRT)) != 0) {
	sc->tz_validchecks++;
	if (sc->tz_validchecks == TZ_VALIDCHECKS) {
	    device_printf(sc->tz_dev,
		"WARNING - current temperature (%d.%dC) exceeds safe limits\n",
		TZ_KELVTOC(sc->tz_temperature));
	    shutdown_nice(RB_POWEROFF);
	} else if (sc->tz_validchecks == TZ_NOTIFYCOUNT)
	    acpi_UserNotify("Thermal", sc->tz_handle, TZ_NOTIFY_CRITICAL);
    } else {
	sc->tz_validchecks = 0;
    }
    sc->tz_thflags = newflags;

    return_VOID;
}

/*
 * Given an object, verify that it's a reference to a device of some sort,
 * and try to switch it off.
 */
static void
acpi_tz_switch_cooler_off(ACPI_OBJECT *obj, void *arg)
{
    ACPI_HANDLE			cooler;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    cooler = acpi_GetReference(NULL, obj);
    if (cooler == NULL) {
	ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get handle\n"));
	return_VOID;
    }

    ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "called to turn %s off\n",
		     acpi_name(cooler)));
    acpi_pwr_switch_consumer(cooler, ACPI_STATE_D3);

    return_VOID;
}

/*
 * Given an object, verify that it's a reference to a device of some sort,
 * and try to switch it on.
 *
 * XXX replication of off/on function code is bad.
 */
static void
acpi_tz_switch_cooler_on(ACPI_OBJECT *obj, void *arg)
{
    struct acpi_tz_softc	*sc = (struct acpi_tz_softc *)arg;
    ACPI_HANDLE			cooler;
    ACPI_STATUS			status;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    cooler = acpi_GetReference(NULL, obj);
    if (cooler == NULL) {
	ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "can't get handle\n"));
	return_VOID;
    }

    ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "called to turn %s on\n",
		     acpi_name(cooler)));
    status = acpi_pwr_switch_consumer(cooler, ACPI_STATE_D0);
    if (ACPI_FAILURE(status)) {
	ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
		    "failed to activate %s - %s\n", acpi_name(cooler),
		    AcpiFormatException(status));
    }

    return_VOID;
}

/*
 * Read/debug-print a parameter, default it to -1.
 */
static void
acpi_tz_getparam(struct acpi_tz_softc *sc, char *node, int *data)
{

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    if (ACPI_FAILURE(acpi_GetInteger(sc->tz_handle, node, data))) {
	*data = -1;
    } else {
	ACPI_DEBUG_PRINT((ACPI_DB_VALUES, "%s.%s = %d\n",
			 acpi_name(sc->tz_handle), node, *data));
    }

    return_VOID;
}

/*
 * Sanity-check a temperature value.  Assume that setpoints
 * should be between 0C and 150C.
 */
static void
acpi_tz_sanity(struct acpi_tz_softc *sc, int *val, char *what)
{
    if (*val != -1 && (*val < TZ_ZEROC || *val > TZ_ZEROC + 1500)) {
	device_printf(sc->tz_dev, "%s value is absurd, ignored (%d.%dC)\n",
		      what, TZ_KELVTOC(*val));
	*val = -1;
    }
}

/*
 * Respond to a sysctl on the active state node.
 */
static int
acpi_tz_active_sysctl(SYSCTL_HANDLER_ARGS)
{
    struct acpi_tz_softc	*sc;
    int				active;
    int		 		error;

    sc = (struct acpi_tz_softc *)oidp->oid_arg1;
    active = sc->tz_active;
    error = sysctl_handle_int(oidp, &active, 0, req);

    /* Error or no new value */
    if (error != 0 || req->newptr == NULL)
	return (error);
    if (active < -1 || active >= TZ_NUMLEVELS)
	return (EINVAL);

    /* Set new preferred level and re-switch */
    sc->tz_requested = active;
    acpi_tz_signal(sc, 0);
    return (0);
}

static void
acpi_tz_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
{
    struct acpi_tz_softc	*sc = (struct acpi_tz_softc *)context;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    switch (notify) {
    case TZ_NOTIFY_TEMPERATURE:
	/* Temperature change occurred */
	acpi_tz_signal(sc, 0);
	break;
    case TZ_NOTIFY_DEVICES:
    case TZ_NOTIFY_LEVELS:
	/* Zone devices/setpoints changed */
	acpi_tz_signal(sc, TZ_FLAG_GETSETTINGS);
	break;
    default:
	ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
		    "unknown Notify event 0x%x\n", notify);
	break;
    }

    acpi_UserNotify("Thermal", h, notify);

    return_VOID;
}

static void
acpi_tz_signal(struct acpi_tz_softc *sc, int flags)
{
    ACPI_LOCK(thermal);
    sc->tz_flags |= flags;
    ACPI_UNLOCK(thermal);
    wakeup(&acpi_tz_proc);
}

/*
 * Notifies can be generated asynchronously but have also been seen to be
 * triggered by other thermal methods.  One system generates a notify of
 * 0x81 when the fan is turned on or off.  Another generates it when _SCP
 * is called.  To handle these situations, we check the zone via
 * acpi_tz_monitor() before evaluating changes to setpoints or the cooling
 * policy.
 */
static void
acpi_tz_timeout(struct acpi_tz_softc *sc, int flags)
{

    /* Check the current temperature and take action based on it */
    acpi_tz_monitor(sc);

    /* If requested, get the power profile settings. */
    if (flags & TZ_FLAG_GETPROFILE)
	acpi_tz_power_profile(sc);

    /*
     * If requested, check for new devices/setpoints.  After finding them,
     * check if we need to switch fans based on the new values.
     */
    if (flags & TZ_FLAG_GETSETTINGS) {
	acpi_tz_establish(sc);
	acpi_tz_monitor(sc);
    }

    /* XXX passive cooling actions? */
}

/*
 * System power profile may have changed; fetch and notify the
 * thermal zone accordingly.
 *
 * Since this can be called from an arbitrary eventhandler, it needs
 * to get the ACPI lock itself.
 */
static void
acpi_tz_power_profile(void *arg)
{
    ACPI_STATUS			status;
    struct acpi_tz_softc	*sc = (struct acpi_tz_softc *)arg;
    int				state;

    state = power_profile_get_state();
    if (state != POWER_PROFILE_PERFORMANCE && state != POWER_PROFILE_ECONOMY)
	return;

    /* check that we haven't decided there's no _SCP method */
    if ((sc->tz_flags & TZ_FLAG_NO_SCP) == 0) {

	/* Call _SCP to set the new profile */
	status = acpi_SetInteger(sc->tz_handle, "_SCP",
	    (state == POWER_PROFILE_PERFORMANCE) ? 0 : 1);
	if (ACPI_FAILURE(status)) {
	    if (status != AE_NOT_FOUND)
		ACPI_VPRINT(sc->tz_dev,
			    acpi_device_get_parent_softc(sc->tz_dev),
			    "can't evaluate %s._SCP - %s\n",
			    acpi_name(sc->tz_handle),
			    AcpiFormatException(status));
	    sc->tz_flags |= TZ_FLAG_NO_SCP;
	} else {
	    /* We have to re-evaluate the entire zone now */
	    acpi_tz_signal(sc, TZ_FLAG_GETSETTINGS);
	}
    }
}

/*
 * Thermal zone monitor thread.
 */
static void
acpi_tz_thread(void *arg)
{
    device_t	*devs;
    int		devcount, i;
    int		flags;
    struct acpi_tz_softc **sc;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    devs = NULL;
    devcount = 0;
    sc = NULL;

    for (;;) {
	/* If the number of devices has changed, re-evaluate. */
	if (devclass_get_maxunit(acpi_tz_devclass) != devcount) {
	    if (devs != NULL) {
		free(devs, M_TEMP);
		free(sc, M_TEMP);
	    }
	    devclass_get_devices(acpi_tz_devclass, &devs, &devcount);
	    sc = malloc(sizeof(struct acpi_tz_softc *) * devcount, M_TEMP,
			M_WAITOK | M_ZERO);
	    for (i = 0; i < devcount; i++)
		sc[i] = device_get_softc(devs[i]);
	}

	/* Check for temperature events and act on them. */
	for (i = 0; i < devcount; i++) {
	    ACPI_LOCK(thermal);
	    flags = sc[i]->tz_flags;
	    sc[i]->tz_flags &= TZ_FLAG_NO_SCP;
	    ACPI_UNLOCK(thermal);
	    acpi_tz_timeout(sc[i], flags);
	}

	/* If more work to do, don't go to sleep yet. */
	ACPI_LOCK(thermal);
	for (i = 0; i < devcount; i++) {
	    if (sc[i]->tz_flags & ~TZ_FLAG_NO_SCP)
		break;
	}

	/*
	 * If we have no more work, sleep for a while, setting PDROP so that
	 * the mutex will not be reacquired.  Otherwise, drop the mutex and
	 * loop to handle more events.
	 */
	if (i == devcount)
	    msleep(&acpi_tz_proc, &thermal_mutex, PZERO | PDROP, "tzpoll",
		hz * acpi_tz_polling_rate);
	else
	    ACPI_UNLOCK(thermal);
    }
}