apm.c

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	cli();
	/* set the clock to 100 Hz */
	outb_p(0x34,0x43);		/* binary, mode 2, LSB/MSB, ch 0 */
	udelay(10);
	outb_p(LATCH & 0xff , 0x40);	/* LSB */
	udelay(10);
	outb(LATCH >> 8 , 0x40);	/* MSB */
	udelay(10);
	restore_flags(flags);
#endif
}

static int send_event(apm_event_t event)
{
	switch (event) {
	case APM_SYS_SUSPEND:
	case APM_CRITICAL_SUSPEND:
	case APM_USER_SUSPEND:
		/* map all suspends to ACPI D3 */
		if (pm_send_all(PM_SUSPEND, (void *)3)) {
			if (event == APM_CRITICAL_SUSPEND) {
				printk(KERN_CRIT "apm: Critical suspend was vetoed, expect armageddon\n" );
				return 0;
			}
			if (apm_info.connection_version > 0x100)
				apm_set_power_state(APM_STATE_REJECT);
			return 0;
		}
		break;
	case APM_NORMAL_RESUME:
	case APM_CRITICAL_RESUME:
		/* map all resumes to ACPI D0 */
		(void) pm_send_all(PM_RESUME, (void *)0);
		break;
	}

	return 1;
}

static int suspend(void)
{
	int		err;
	struct apm_user	*as;

	get_time_diff();
	cli();
	err = apm_set_power_state(APM_STATE_SUSPEND);
	reinit_timer();
	set_time();
	if (err == APM_NO_ERROR)
		err = APM_SUCCESS;
	if (err != APM_SUCCESS)
		apm_error("suspend", err);
	send_event(APM_NORMAL_RESUME);
	sti();
	queue_event(APM_NORMAL_RESUME, NULL);
	for (as = user_list; as != NULL; as = as->next) {
		as->suspend_wait = 0;
		as->suspend_result = ((err == APM_SUCCESS) ? 0 : -EIO);
	}
	ignore_normal_resume = 1;
	wake_up_interruptible(&apm_suspend_waitqueue);
	return err;
}

static void standby(void)
{
	int	err;

	get_time_diff();
	err = apm_set_power_state(APM_STATE_STANDBY);
	if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
		apm_error("standby", err);
}

static apm_event_t get_event(void)
{
	int		error;
	apm_event_t	event;
	apm_eventinfo_t	info;

	static int notified;

	/* we don't use the eventinfo */
	error = apm_get_event(&event, &info);
	if (error == APM_SUCCESS)
		return event;

	if ((error != APM_NO_EVENTS) && (notified++ == 0))
		apm_error("get_event", error);

	return 0;
}

static void check_events(void)
{
	apm_event_t		event;
	static unsigned long	last_resume;
	static int		ignore_bounce;

	while ((event = get_event()) != 0) {
		if (debug) {
			if (event <= NR_APM_EVENT_NAME)
				printk(KERN_DEBUG "apm: received %s notify\n",
				       apm_event_name[event - 1]);
			else
				printk(KERN_DEBUG "apm: received unknown "
				       "event 0x%02x\n", event);
		}
		if (ignore_bounce
		    && ((jiffies - last_resume) > bounce_interval))
			ignore_bounce = 0;
		if (ignore_normal_resume && (event != APM_NORMAL_RESUME))
			ignore_normal_resume = 0;

		switch (event) {
		case APM_SYS_STANDBY:
		case APM_USER_STANDBY:
			if (send_event(event)) {
				queue_event(event, NULL);
				if (standbys_pending <= 0)
					standby();
			}
			break;

		case APM_USER_SUSPEND:
#ifdef CONFIG_APM_IGNORE_USER_SUSPEND
			if (apm_info.connection_version > 0x100)
				apm_set_power_state(APM_STATE_REJECT);
			break;
#endif
		case APM_SYS_SUSPEND:
			if (ignore_bounce) {
				if (apm_info.connection_version > 0x100)
					apm_set_power_state(APM_STATE_REJECT);
				break;
			}
			/*
			 * If we are already processing a SUSPEND,
			 * then further SUSPEND events from the BIOS
			 * will be ignored.  We also return here to
			 * cope with the fact that the Thinkpads keep
			 * sending a SUSPEND event until something else
			 * happens!
			 */
			if (waiting_for_resume)
				return;
			if (send_event(event)) {
				queue_event(event, NULL);
				waiting_for_resume = 1;
				if (suspends_pending <= 0)
					(void) suspend();
			}
			break;

		case APM_NORMAL_RESUME:
		case APM_CRITICAL_RESUME:
		case APM_STANDBY_RESUME:
			waiting_for_resume = 0;
			last_resume = jiffies;
			ignore_bounce = 1;
			if ((event != APM_NORMAL_RESUME)
			    || (ignore_normal_resume == 0)) {
				set_time();
				send_event(event);
				queue_event(event, NULL);
			}
			break;

		case APM_CAPABILITY_CHANGE:
		case APM_LOW_BATTERY:
		case APM_POWER_STATUS_CHANGE:
			send_event(event);
			queue_event(event, NULL);
			break;

		case APM_UPDATE_TIME:
			set_time();
			break;

		case APM_CRITICAL_SUSPEND:
			send_event(event);
			/*
			 * We can only hope it worked - we are not allowed
			 * to reject a critical suspend.
			 */
			(void) suspend();
			break;
		}
	}
}

static void apm_event_handler(void)
{
	static int	pending_count = 4;
	int		err;

	if ((standbys_pending > 0) || (suspends_pending > 0)) {
		if ((apm_info.connection_version > 0x100) && (pending_count-- <= 0)) {
			pending_count = 4;
			if (debug)
				printk(KERN_DEBUG "apm: setting state busy\n");
			err = apm_set_power_state(APM_STATE_BUSY);
			if (err)
				apm_error("busy", err);
		}
	} else
		pending_count = 4;
	check_events();
}

/*
 * This is the APM thread main loop.
 *
 * Check whether we're the only running process to
 * decide if we should just power down.
 *
 */
#define system_idle() (nr_running == 1)

static void apm_mainloop(void)
{
	int timeout = HZ;
	DECLARE_WAITQUEUE(wait, current);

	add_wait_queue(&apm_waitqueue, &wait);
	set_current_state(TASK_INTERRUPTIBLE);
	for (;;) {
		/* Nothing to do, just sleep for the timeout */
		timeout = 2*timeout;
		if (timeout > APM_CHECK_TIMEOUT)
			timeout = APM_CHECK_TIMEOUT;
		schedule_timeout(timeout);
		if (exit_kapmd)
			break;

		/*
		 * Ok, check all events, check for idle (and mark us sleeping
		 * so as not to count towards the load average)..
		 */
		set_current_state(TASK_INTERRUPTIBLE);
		apm_event_handler();
#ifdef CONFIG_APM_CPU_IDLE
		if (!system_idle())
			continue;
		if (apm_do_idle()) {
			unsigned long start = jiffies;
			while ((!exit_kapmd) && system_idle()) {
				apm_do_idle();
				if ((jiffies - start) > APM_CHECK_TIMEOUT) {
					apm_event_handler();
					start = jiffies;
				}
			}
			apm_do_busy();
			apm_event_handler();
			timeout = 1;
		}
#endif
	}
	remove_wait_queue(&apm_waitqueue, &wait);
}

static int check_apm_user(struct apm_user *as, const char *func)
{
	if ((as == NULL) || (as->magic != APM_BIOS_MAGIC)) {
		printk(KERN_ERR "apm: %s passed bad filp\n", func);
		return 1;
	}
	return 0;
}

static ssize_t do_read(struct file *fp, char *buf, size_t count, loff_t *ppos)
{
	struct apm_user *	as;
	int			i;
	apm_event_t		event;
	DECLARE_WAITQUEUE(wait, current);

	as = fp->private_data;
	if (check_apm_user(as, "read"))
		return -EIO;
	if (count < sizeof(apm_event_t))
		return -EINVAL;
	if (queue_empty(as)) {
		if (fp->f_flags & O_NONBLOCK)
			return -EAGAIN;
		add_wait_queue(&apm_waitqueue, &wait);
repeat:
		set_current_state(TASK_INTERRUPTIBLE);
		if (queue_empty(as) && !signal_pending(current)) {
			schedule();
			goto repeat;
		}
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&apm_waitqueue, &wait);
	}
	i = count;
	while ((i >= sizeof(event)) && !queue_empty(as)) {
		event = get_queued_event(as);
		if (copy_to_user(buf, &event, sizeof(event))) {
			if (i < count)
				break;
			return -EFAULT;
		}
		switch (event) {
		case APM_SYS_SUSPEND:
		case APM_USER_SUSPEND:
			as->suspends_read++;
			break;

		case APM_SYS_STANDBY:
		case APM_USER_STANDBY:
			as->standbys_read++;
			break;
		}
		buf += sizeof(event);
		i -= sizeof(event);
	}
	if (i < count)
		return count - i;
	if (signal_pending(current))
		return -ERESTARTSYS;
	return 0;
}

static unsigned int do_poll(struct file *fp, poll_table * wait)
{
	struct apm_user * as;

	as = fp->private_data;
	if (check_apm_user(as, "poll"))
		return 0;
	poll_wait(fp, &apm_waitqueue, wait);
	if (!queue_empty(as))
		return POLLIN | POLLRDNORM;
	return 0;
}

static int do_ioctl(struct inode * inode, struct file *filp,
		    u_int cmd, u_long arg)
{
	struct apm_user *	as;
	DECLARE_WAITQUEUE(wait, current);

	as = filp->private_data;
	if (check_apm_user(as, "ioctl"))
		return -EIO;
	if (!as->suser)
		return -EPERM;
	switch (cmd) {
	case APM_IOC_STANDBY:
		if (as->standbys_read > 0) {
			as->standbys_read--;
			as->standbys_pending--;
			standbys_pending--;
		} else if (!send_event(APM_USER_STANDBY))
			return -EAGAIN;
		else
			queue_event(APM_USER_STANDBY, as);
		if (standbys_pending <= 0)
			standby();
		break;
	case APM_IOC_SUSPEND:
		if (as->suspends_read > 0) {
			as->suspends_read--;
			as->suspends_pending--;
			suspends_pending--;
		} else if (!send_event(APM_USER_SUSPEND))
			return -EAGAIN;
		else
			queue_event(APM_USER_SUSPEND, as);
		if (suspends_pending <= 0) {
			if (suspend() != APM_SUCCESS)
				return -EIO;
		} else {
			as->suspend_wait = 1;
			add_wait_queue(&apm_suspend_waitqueue, &wait);
			while (1) {
				set_current_state(TASK_INTERRUPTIBLE);
				if ((as->suspend_wait == 0)
				    || signal_pending(current))
					break;
				schedule();
			}
			set_current_state(TASK_RUNNING);
			remove_wait_queue(&apm_suspend_waitqueue, &wait);
			return as->suspend_result;
		}
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

static int do_release(struct inode * inode, struct file * filp)
{
	struct apm_user *	as;

	as = filp->private_data;
	if (check_apm_user(as, "release"))
		return 0;
	filp->private_data = NULL;
	lock_kernel();
	if (as->standbys_pending > 0) {
		standbys_pending -= as->standbys_pending;
		if (standbys_pending <= 0)
			standby();
	}
	if (as->suspends_pending > 0) {
		suspends_pending -= as->suspends_pending;
		if (suspends_pending <= 0)
			(void) suspend();
	}
	if (user_list == as)
		user_list = as->next;
	else {
		struct apm_user *	as1;

		for (as1 = user_list;
		     (as1 != NULL) && (as1->next != as);
		     as1 = as1->next)
			;
		if (as1 == NULL)
			printk(KERN_ERR "apm: filp not in user list\n");
		else
			as1->next = as->next;
	}
	unlock_kernel();
	kfree(as);
	return 0;
}

static int do_open(struct inode * inode, struct file * filp)
{
	struct apm_user *	as;