xref: /src/sys/dev/apm/apm.c

/*	$NetBSD: apm.c,v 1.32 2017/10/25 08:12:38 maya Exp $ */

/*-
 * Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by John Kohl and Christopher G. Demetriou.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */
/*
 * from: sys/arch/i386/i386/apm.c,v 1.49 2000/05/08
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: apm.c,v 1.32 2017/10/25 08:12:38 maya Exp $");

#include "opt_apm.h"

#if defined(DEBUG) && !defined(APMDEBUG)
#define	APMDEBUG
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/device.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/poll.h>
#include <sys/conf.h>

#include <dev/apm/apmvar.h>

#ifdef APMDEBUG
#define DPRINTF(f, x)		do { if (apmdebug & (f)) printf x; } while (0)


#ifdef APMDEBUG_VALUE
int	apmdebug = APMDEBUG_VALUE;
#else
int	apmdebug = 0;
#endif /* APMDEBUG_VALUE */

#else
#define	DPRINTF(f, x)		/**/
#endif /* APMDEBUG */

#define	SCFLAG_OREAD	0x0000001
#define	SCFLAG_OWRITE	0x0000002
#define	SCFLAG_OPEN	(SCFLAG_OREAD|SCFLAG_OWRITE)

#define	APMUNIT(dev)	(minor(dev)&0xf0)
#define	APM(dev)	(minor(dev)&0x0f)
#define APM_NORMAL	0
#define APM_CTL	8

/*
 * A brief note on the locking protocol: it's very simple; we
 * assert an exclusive lock any time thread context enters the
 * APM module.  This is both the APM thread itself, as well as
 * user context.
 */
#define	APM_LOCK(apmsc)						\
	(void) mutex_enter(&(apmsc)->sc_lock)
#define	APM_UNLOCK(apmsc)						\
	(void) mutex_exit(&(apmsc)->sc_lock)

static void	apm_event_handle(struct apm_softc *, u_int, u_int);
static void	apm_periodic_check(struct apm_softc *);
static void	apm_thread(void *);
static void	apm_perror(const char *, int, ...)
		    __attribute__((__format__(__printf__,1,3)));
#ifdef APM_POWER_PRINT
static void	apm_power_print(struct apm_softc *, struct apm_power_info *);
#endif
static int	apm_record_event(struct apm_softc *, u_int);
static void	apm_set_ver(struct apm_softc *);
static void	apm_standby(struct apm_softc *);
static void	apm_suspend(struct apm_softc *);
static void	apm_resume(struct apm_softc *, u_int, u_int);

extern struct cfdriver apm_cd;

dev_type_open(apmopen);
dev_type_close(apmclose);
dev_type_ioctl(apmioctl);
dev_type_poll(apmpoll);
dev_type_kqfilter(apmkqfilter);

const struct cdevsw apm_cdevsw = {
	.d_open = apmopen,
	.d_close = apmclose,
	.d_read = noread,
	.d_write = nowrite,
	.d_ioctl = apmioctl,
	.d_stop = nostop,
	.d_tty = notty,
	.d_poll = apmpoll,
	.d_mmap = nommap,
	.d_kqfilter = apmkqfilter,
	.d_discard = nodiscard,
	.d_flag = D_OTHER,
};

/* configurable variables */
#ifdef APM_NO_STANDBY
int	apm_do_standby = 0;
#else
int	apm_do_standby = 1;
#endif
#ifdef APM_V10_ONLY
int	apm_v11_enabled = 0;
#else
int	apm_v11_enabled = 1;
#endif
#ifdef APM_NO_V12
int	apm_v12_enabled = 0;
#else
int	apm_v12_enabled = 1;
#endif

/* variables used during operation (XXX cgd) */
u_char	apm_majver, apm_minver;
int	apm_inited;
int	apm_standbys, apm_userstandbys, apm_suspends, apm_battlow;
int	apm_damn_fool_bios, apm_op_inprog;
int	apm_evindex;

static int apm_spl;		/* saved spl while suspended */

const char *
apm_strerror(int code)
{
	switch (code) {
	case APM_ERR_PM_DISABLED:
		return ("power management disabled");
	case APM_ERR_REALALREADY:
		return ("real mode interface already connected");
	case APM_ERR_NOTCONN:
		return ("interface not connected");
	case APM_ERR_16ALREADY:
		return ("16-bit interface already connected");
	case APM_ERR_16NOTSUPP:
		return ("16-bit interface not supported");
	case APM_ERR_32ALREADY:
		return ("32-bit interface already connected");
	case APM_ERR_32NOTSUPP:
		return ("32-bit interface not supported");
	case APM_ERR_UNRECOG_DEV:
		return ("unrecognized device ID");
	case APM_ERR_ERANGE:
		return ("parameter out of range");
	case APM_ERR_NOTENGAGED:
		return ("interface not engaged");
	case APM_ERR_UNABLE:
		return ("unable to enter requested state");
	case APM_ERR_NOEVENTS:
		return ("no pending events");
	case APM_ERR_NOT_PRESENT:
		return ("no APM present");
	default:
		return ("unknown error code");
	}
}

static void
apm_perror(const char *str, int errinfo, ...) /* XXX cgd */
{
	va_list ap;

	printf("APM ");

	va_start(ap, errinfo);
	vprintf(str, ap);			/* XXX cgd */
	va_end(ap);

	printf(": %s\n", apm_strerror(errinfo));
}

#ifdef APM_POWER_PRINT
static void
apm_power_print(struct apm_softc *sc, struct apm_power_info *pi)
{

	if (pi->battery_life != APM_BATT_LIFE_UNKNOWN) {
		aprint_normal_dev(sc->sc_dev,
		    "battery life expectancy: %d%%\n",
		    pi->battery_life);
	}
	aprint_normal_dev(sc->sc_dev, "A/C state: ");
	switch (pi->ac_state) {
	case APM_AC_OFF:
		printf("off\n");
		break;
	case APM_AC_ON:
		printf("on\n");
		break;
	case APM_AC_BACKUP:
		printf("backup power\n");
		break;
	default:
	case APM_AC_UNKNOWN:
		printf("unknown\n");
		break;
	}
	aprint_normal_dev(sc->sc_dev, "battery charge state:");
	if (apm_minver == 0)
		switch (pi->battery_state) {
		case APM_BATT_HIGH:
			printf("high\n");
			break;
		case APM_BATT_LOW:
			printf("low\n");
			break;
		case APM_BATT_CRITICAL:
			printf("critical\n");
			break;
		case APM_BATT_CHARGING:
			printf("charging\n");
			break;
		case APM_BATT_UNKNOWN:
			printf("unknown\n");
			break;
		default:
			printf("undecoded state %x\n", pi->battery_state);
			break;
		}
	else if (apm_minver >= 1) {
		if (pi->battery_flags & APM_BATT_FLAG_NO_SYSTEM_BATTERY)
			printf(" no battery");
		else {
			if (pi->battery_flags & APM_BATT_FLAG_HIGH)
				printf(" high");
			if (pi->battery_flags & APM_BATT_FLAG_LOW)
				printf(" low");
			if (pi->battery_flags & APM_BATT_FLAG_CRITICAL)
				printf(" critical");
			if (pi->battery_flags & APM_BATT_FLAG_CHARGING)
				printf(" charging");
		}
		printf("\n");
		if (pi->minutes_valid) {
			aprint_normal_dev(sc->sc_dev, "estimated ");
			if (pi->minutes_left / 60)
				printf("%dh ", pi->minutes_left / 60);
			printf("%dm\n", pi->minutes_left % 60);
		}
	}
	return;
}
#endif

static void
apm_suspend(struct apm_softc *sc)
{
	int error;

	if (sc->sc_power_state == PWR_SUSPEND) {
#ifdef APMDEBUG
		aprint_debug_dev(sc->sc_dev,
		    "apm_suspend: already suspended?\n");
#endif
		return;
	}
	sc->sc_power_state = PWR_SUSPEND;

	if (!(sc->sc_hwflags & APM_F_DONT_RUN_HOOKS)) {
		pmf_system_suspend(PMF_Q_NONE);
		apm_spl = splhigh();
	}

	error = (*sc->sc_ops->aa_set_powstate)(sc->sc_cookie, APM_DEV_ALLDEVS,
	    APM_SYS_SUSPEND);

	if (error)
		apm_resume(sc, 0, 0);
	else
		apm_resume(sc, APM_SYS_STANDBY_RESUME, 0);
}

static void
apm_standby(struct apm_softc *sc)
{
	int error;

	if (sc->sc_power_state == PWR_STANDBY) {
#ifdef APMDEBUG
		aprint_debug_dev(sc->sc_dev,
		    "apm_standby: already standing by?\n");
#endif
		return;
	}
	sc->sc_power_state = PWR_STANDBY;

	if (!(sc->sc_hwflags & APM_F_DONT_RUN_HOOKS)) {
		pmf_system_suspend(PMF_Q_NONE);
		apm_spl = splhigh();
	}
	error = (*sc->sc_ops->aa_set_powstate)(sc->sc_cookie, APM_DEV_ALLDEVS,
	    APM_SYS_STANDBY);
	if (error)
		apm_resume(sc, 0, 0);
	else
		apm_resume(sc, APM_SYS_STANDBY_RESUME, 0);
}

static void
apm_resume(struct apm_softc *sc, u_int event_type, u_int event_info)
{
	if (sc->sc_power_state == PWR_RESUME) {
#ifdef APMDEBUG
		aprint_debug_dev(sc->sc_dev, "apm_resume: already running?\n");
#endif
		return;
	}
	sc->sc_power_state = PWR_RESUME;

#ifdef TIMER_FREQ
	/*
	 * Some system requires its clock to be initialized after hybernation.
	 */
	initrtclock(TIMER_FREQ);
#endif

	inittodr(time_second);
	if (!(sc->sc_hwflags & APM_F_DONT_RUN_HOOKS)) {
		splx(apm_spl);
		pmf_system_resume(PMF_Q_NONE);
	}

	apm_record_event(sc, event_type);
}

/*
 * return 0 if the user will notice and handle the event,
 * return 1 if the kernel driver should do so.
 */
static int
apm_record_event(struct apm_softc *sc, u_int event_type)
{
	struct apm_event_info *evp;

	if ((sc->sc_flags & SCFLAG_OPEN) == 0)
		return 1;		/* no user waiting */
	if (sc->sc_event_count == APM_NEVENTS)
		return 1;			/* overflow */
	evp = &sc->sc_event_list[sc->sc_event_ptr];
	sc->sc_event_count++;
	sc->sc_event_ptr++;
	sc->sc_event_ptr %= APM_NEVENTS;
	evp->type = event_type;
	evp->index = ++apm_evindex;
	selnotify(&sc->sc_rsel, 0, 0);
	return (sc->sc_flags & SCFLAG_OWRITE) ? 0 : 1; /* user may handle */
}

static void
apm_event_handle(struct apm_softc *sc, u_int event_code, u_int event_info)
{
	int error;
	const char *code;
	struct apm_power_info pi;

	switch (event_code) {
	case APM_USER_STANDBY_REQ:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: user standby request\n"));
		if (apm_do_standby) {
			if (apm_op_inprog == 0 && apm_record_event(sc, event_code))
				apm_userstandbys++;
			apm_op_inprog++;
			(void)(*sc->sc_ops->aa_set_powstate)(sc->sc_cookie,
			    APM_DEV_ALLDEVS, APM_LASTREQ_INPROG);
		} else {
			(void)(*sc->sc_ops->aa_set_powstate)(sc->sc_cookie,
			    APM_DEV_ALLDEVS, APM_LASTREQ_REJECTED);
			/* in case BIOS hates being spurned */
			(*sc->sc_ops->aa_enable)(sc->sc_cookie, 1);
		}
		break;

	case APM_STANDBY_REQ:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: system standby request\n"));
		if (apm_op_inprog) {
			DPRINTF(APMDEBUG_EVENTS | APMDEBUG_ANOM,
			    ("damn fool BIOS did not wait for answer\n"));
			/* just give up the fight */
			apm_damn_fool_bios = 1;
		}
		if (apm_do_standby) {
			if (apm_op_inprog == 0 &&
			    apm_record_event(sc, event_code))
				apm_standbys++;
			apm_op_inprog++;
			(void)(*sc->sc_ops->aa_set_powstate)(sc->sc_cookie,
			    APM_DEV_ALLDEVS, APM_LASTREQ_INPROG);
		} else {
			(void)(*sc->sc_ops->aa_set_powstate)(sc->sc_cookie,
			    APM_DEV_ALLDEVS, APM_LASTREQ_REJECTED);
			/* in case BIOS hates being spurned */
			(*sc->sc_ops->aa_enable)(sc->sc_cookie, 1);
		}
		break;

	case APM_USER_SUSPEND_REQ:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: user suspend request\n"));
		if (apm_op_inprog == 0 && apm_record_event(sc, event_code))
			apm_suspends++;
		apm_op_inprog++;
		(void)(*sc->sc_ops->aa_set_powstate)(sc->sc_cookie,
		    APM_DEV_ALLDEVS, APM_LASTREQ_INPROG);
		break;

	case APM_SUSPEND_REQ:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: system suspend request\n"));
		if (apm_op_inprog) {
			DPRINTF(APMDEBUG_EVENTS | APMDEBUG_ANOM,
			    ("damn fool BIOS did not wait for answer\n"));
			/* just give up the fight */
			apm_damn_fool_bios = 1;
		}
		if (apm_op_inprog == 0 && apm_record_event(sc, event_code))
			apm_suspends++;
		apm_op_inprog++;
		(void)(*sc->sc_ops->aa_set_powstate)(sc->sc_cookie,
		    APM_DEV_ALLDEVS, APM_LASTREQ_INPROG);
		break;

	case APM_POWER_CHANGE:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: power status change\n"));
		error = (*sc->sc_ops->aa_get_powstat)(sc->sc_cookie, 0, &pi);
#ifdef APM_POWER_PRINT
		/* only print if nobody is catching events. */
		if (error == 0 &&
		    (sc->sc_flags & (SCFLAG_OREAD|SCFLAG_OWRITE)) == 0)
			apm_power_print(sc, &pi);
#else
		__USE(error);
#endif
		apm_record_event(sc, event_code);
		break;

	case APM_NORMAL_RESUME:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: resume system\n"));
		apm_resume(sc, event_code, event_info);
		break;

	case APM_CRIT_RESUME:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: critical resume system"));
		apm_resume(sc, event_code, event_info);
		break;

	case APM_SYS_STANDBY_RESUME:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: system standby resume\n"));
		apm_resume(sc, event_code, event_info);
		break;

	case APM_UPDATE_TIME:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: update time\n"));
		apm_resume(sc, event_code, event_info);
		break;

	case APM_CRIT_SUSPEND_REQ:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: critical system suspend\n"));
		apm_record_event(sc, event_code);
		apm_suspend(sc);
		break;

	case APM_BATTERY_LOW:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: battery low\n"));
		apm_battlow++;
		apm_record_event(sc, event_code);
		break;

	case APM_CAP_CHANGE:
		DPRINTF(APMDEBUG_EVENTS, ("apmev: capability change\n"));
		if (apm_minver < 2) {
			DPRINTF(APMDEBUG_EVENTS, ("apm: unexpected event\n"));
		} else {
			u_int numbatts, capflags;
			(*sc->sc_ops->aa_get_capabilities)(sc->sc_cookie,
			    &numbatts, &capflags);
			(*sc->sc_ops->aa_get_powstat)(sc->sc_cookie, 0, &pi);
		}
		break;

	default:
		switch (event_code >> 8) {
			case 0:
				code = "reserved system";
				break;
			case 1:
				code = "reserved device";
				break;
			case 2:
				code = "OEM defined";
				break;
			default:
				code = "reserved";
				break;
		}
		printf("APM: %s event code %x\n", code, event_code);
	}
}

static void
apm_periodic_check(struct apm_softc *sc)
{
	int error;
	u_int event_code, event_info;


	/*
	 * tell the BIOS we're working on it, if asked to do a
	 * suspend/standby
	 */
	if (apm_op_inprog)
		(*sc->sc_ops->aa_set_powstate)(sc->sc_cookie, APM_DEV_ALLDEVS,
		    APM_LASTREQ_INPROG);

	while ((error = (*sc->sc_ops->aa_get_event)(sc->sc_cookie, &event_code,
	    &event_info)) == 0 && !apm_damn_fool_bios)
		apm_event_handle(sc, event_code, event_info);

	if (error != APM_ERR_NOEVENTS)
		apm_perror("get event", error);
	if (apm_suspends) {
		apm_op_inprog = 0;
		apm_suspend(sc);
	} else if (apm_standbys || apm_userstandbys) {
		apm_op_inprog = 0;
		apm_standby(sc);
	}
	apm_suspends = apm_standbys = apm_battlow = apm_userstandbys = 0;
	apm_damn_fool_bios = 0;
}

static void
apm_set_ver(struct apm_softc *sc)
{

	if (apm_v12_enabled &&
	    APM_MAJOR_VERS(sc->sc_vers) == 1 &&
	    APM_MINOR_VERS(sc->sc_vers) == 2) {
		apm_majver = 1;
		apm_minver = 2;
		goto ok;
	}

	if (apm_v11_enabled &&
	    APM_MAJOR_VERS(sc->sc_vers) == 1 &&
	    APM_MINOR_VERS(sc->sc_vers) == 1) {
		apm_majver = 1;
		apm_minver = 1;
	} else {
		apm_majver = 1;
		apm_minver = 0;
	}
ok:
	aprint_normal("Power Management spec V%d.%d", apm_majver, apm_minver);
	apm_inited = 1;
}

int
apm_match(void)
{
	static int got;
	return !got++;
}

void
apm_attach(struct apm_softc *sc)
{
	u_int numbatts, capflags;

	aprint_normal(": ");

	switch ((APM_MAJOR_VERS(sc->sc_vers) << 8) + APM_MINOR_VERS(sc->sc_vers)) {
	case 0x0100:
		apm_v11_enabled = 0;
		apm_v12_enabled = 0;
		break;
	case 0x0101:
		apm_v12_enabled = 0;
		/* fall through */
	case 0x0102:
	default:
		break;
	}

	apm_set_ver(sc);	/* prints version info */
	aprint_normal("\n");
	if (apm_minver >= 2)
		(*sc->sc_ops->aa_get_capabilities)(sc->sc_cookie, &numbatts,
		    &capflags);

	/*
	 * enable power management
	 */
	(*sc->sc_ops->aa_enable)(sc->sc_cookie, 1);

	if (sc->sc_ops->aa_cpu_busy)
		(*sc->sc_ops->aa_cpu_busy)(sc->sc_cookie);

	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);

	/* Initial state is `resumed'. */
	sc->sc_power_state = PWR_RESUME;
	selinit(&sc->sc_rsel);
	selinit(&sc->sc_xsel);

	/* Do an initial check. */
	apm_periodic_check(sc);

	/*
	 * Create a kernel thread to periodically check for APM events,
	 * and notify other subsystems when they occur.
	 */
	if (kthread_create(PRI_NONE, 0, NULL, apm_thread, sc,
	    &sc->sc_thread, "%s", device_xname(sc->sc_dev)) != 0) {
		/*
		 * We were unable to create the APM thread; bail out.
		 */
		if (sc->sc_ops->aa_disconnect)
			(*sc->sc_ops->aa_disconnect)(sc->sc_cookie);
		aprint_error_dev(sc->sc_dev, "unable to create thread, "
		    "kernel APM support disabled\n");
	}

	if (!pmf_device_register(sc->sc_dev, NULL, NULL))
		aprint_error_dev(sc->sc_dev, "couldn't establish power handler\n");
}

void
apm_thread(void *arg)
{
	struct apm_softc *apmsc = arg;

	/*
	 * Loop forever, doing a periodic check for APM events.
	 */
	for (;;) {
		APM_LOCK(apmsc);
		apm_periodic_check(apmsc);
		APM_UNLOCK(apmsc);
		(void) tsleep(apmsc, PWAIT, "apmev",  (8 * hz) / 7);
	}
}

int
apmopen(dev_t dev, int flag, int mode, struct lwp *l)
{
	int ctl = APM(dev);
	int error = 0;
	struct apm_softc *sc;

	sc = device_lookup_private(&apm_cd, APMUNIT(dev));
	if (!sc)
		return ENXIO;

	if (!apm_inited)
		return ENXIO;

	DPRINTF(APMDEBUG_DEVICE,
	    ("apmopen: pid %d flag %x mode %x\n", l->l_proc->p_pid, flag, mode));

	APM_LOCK(sc);
	switch (ctl) {
	case APM_CTL:
		if (!(flag & FWRITE)) {
			error = EINVAL;
			break;
		}
		if (sc->sc_flags & SCFLAG_OWRITE) {
			error = EBUSY;
			break;
		}
		sc->sc_flags |= SCFLAG_OWRITE;
		break;
	case APM_NORMAL:
		if (!(flag & FREAD) || (flag & FWRITE)) {
			error = EINVAL;
			break;
		}
		sc->sc_flags |= SCFLAG_OREAD;
		break;
	default:
		error = ENXIO;
		break;
	}
	APM_UNLOCK(sc);

	return (error);
}

int
apmclose(dev_t dev, int flag, int mode,
	struct lwp *l)
{
	struct apm_softc *sc = device_lookup_private(&apm_cd, APMUNIT(dev));
	int ctl = APM(dev);

	DPRINTF(APMDEBUG_DEVICE,
	    ("apmclose: pid %d flag %x mode %x\n", l->l_proc->p_pid, flag, mode));

	APM_LOCK(sc);
	switch (ctl) {
	case APM_CTL:
		sc->sc_flags &= ~SCFLAG_OWRITE;
		break;
	case APM_NORMAL:
		sc->sc_flags &= ~SCFLAG_OREAD;
		break;
	}
	if ((sc->sc_flags & SCFLAG_OPEN) == 0) {
		sc->sc_event_count = 0;
		sc->sc_event_ptr = 0;
	}
	APM_UNLOCK(sc);
	return 0;
}

int
apmioctl(dev_t dev, u_long cmd, void *data, int flag,
	struct lwp *l)
{
	struct apm_softc *sc = device_lookup_private(&apm_cd, APMUNIT(dev));
	struct apm_power_info *powerp;
	struct apm_event_info *evp;
#if 0
	struct apm_ctl *actl;
#endif
	int i, error = 0;
	int batt_flags;
	struct apm_ctl *actl;

	APM_LOCK(sc);
	switch (cmd) {
	case APM_IOC_STANDBY:
		if (!apm_do_standby) {
			error = EOPNOTSUPP;
			break;
		}

		if ((flag & FWRITE) == 0) {
			error = EBADF;
			break;
		}
		apm_userstandbys++;
		break;

	case APM_IOC_DEV_CTL:
		actl = (struct apm_ctl *)data;
		if ((flag & FWRITE) == 0) {
			error = EBADF;
			break;
		}
#if 0
		apm_get_powstate(actl->dev); /* XXX */
#endif
		error = (*sc->sc_ops->aa_set_powstate)(sc->sc_cookie, actl->dev,
		    actl->mode);
		apm_suspends++;
 		break;

	case APM_IOC_SUSPEND:
		if ((flag & FWRITE) == 0) {
			error = EBADF;
			break;
		}
		apm_suspends++;
		break;

	case APM_IOC_NEXTEVENT:
		if (!sc->sc_event_count)
			error = EAGAIN;
		else {
			evp = (struct apm_event_info *)data;
			i = sc->sc_event_ptr + APM_NEVENTS - sc->sc_event_count;
			i %= APM_NEVENTS;
			*evp = sc->sc_event_list[i];
			sc->sc_event_count--;
		}
		break;

	case OAPM_IOC_GETPOWER:
	case APM_IOC_GETPOWER:
		powerp = (struct apm_power_info *)data;
		if ((error = (*sc->sc_ops->aa_get_powstat)(sc->sc_cookie, 0,
		    powerp)) != 0) {
			apm_perror("ioctl get power status", error);
			error = EIO;
			break;
		}
		switch (apm_minver) {
		case 0:
			break;
		case 1:
		default:
			batt_flags = powerp->battery_flags;
			powerp->battery_state = APM_BATT_UNKNOWN;
			if (batt_flags & APM_BATT_FLAG_HIGH)
				powerp->battery_state = APM_BATT_HIGH;
			else if (batt_flags & APM_BATT_FLAG_LOW)
				powerp->battery_state = APM_BATT_LOW;
			else if (batt_flags & APM_BATT_FLAG_CRITICAL)
				powerp->battery_state = APM_BATT_CRITICAL;
			else if (batt_flags & APM_BATT_FLAG_CHARGING)
				powerp->battery_state = APM_BATT_CHARGING;
			else if (batt_flags & APM_BATT_FLAG_NO_SYSTEM_BATTERY)
				powerp->battery_state = APM_BATT_ABSENT;
			break;
		}
		break;

	default:
		error = ENOTTY;
	}
	APM_UNLOCK(sc);

	return (error);
}

int
apmpoll(dev_t dev, int events, struct lwp *l)
{
	struct apm_softc *sc = device_lookup_private(&apm_cd, APMUNIT(dev));
	int revents = 0;

	APM_LOCK(sc);
	if (events & (POLLIN | POLLRDNORM)) {
		if (sc->sc_event_count)
			revents |= events & (POLLIN | POLLRDNORM);
		else
			selrecord(l, &sc->sc_rsel);
	}
	APM_UNLOCK(sc);

	return (revents);
}

static void
filt_apmrdetach(struct knote *kn)
{
	struct apm_softc *sc = kn->kn_hook;

	APM_LOCK(sc);
	SLIST_REMOVE(&sc->sc_rsel.sel_klist, kn, knote, kn_selnext);
	APM_UNLOCK(sc);
}

static int
filt_apmread(struct knote *kn, long hint)
{
	struct apm_softc *sc = kn->kn_hook;

	kn->kn_data = sc->sc_event_count;
	return (kn->kn_data > 0);
}

static const struct filterops apmread_filtops = {
	.f_isfd = 1,
	.f_attach = NULL,
	.f_detach = filt_apmrdetach,
	.f_event = filt_apmread,
};

int
apmkqfilter(dev_t dev, struct knote *kn)
{
	struct apm_softc *sc = device_lookup_private(&apm_cd, APMUNIT(dev));
	struct klist *klist;

	switch (kn->kn_filter) {
	case EVFILT_READ:
		klist = &sc->sc_rsel.sel_klist;
		kn->kn_fop = &apmread_filtops;
		break;

	default:
		return (EINVAL);
	}

	kn->kn_hook = sc;

	APM_LOCK(sc);
	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
	APM_UNLOCK(sc);

	return (0);
}