static inline int
__tti_mod_timer(struct tti_timer_list *timer, unsigned long expires, bool pending_only)
{
	struct tti_tvec_base *base = _tti_tvec_base;
	int ret = 0;

	BUG_ON(!timer->function);

    if (tti_timer_pending(timer)) {
		detach_timer(timer, 0);
		if (timer->expires == base->next_timer)
			base->next_timer = base->timer_jiffies;
		ret = 1;
	} else {
		if (pending_only)
			goto out;
	}

    debug_activate(timer, expires);

    timer->expires = expires;
	if (time_before(timer->expires, base->next_timer))
		base->next_timer = timer->expires;
	tti_internal_add_timer(base, timer);

out:
    return ret;
}

/*
 * enqueue_hrtimer - internal function to (re)start a timer
 *
 * The timer is inserted in expiry order. Insertion into the
 * red black tree is O(log(n)). Must hold the base lock.
 *
 * Returns 1 when the new timer is the leftmost timer in the tree.
 */
static int enqueue_hrtimer(struct hrtimer *timer,
			   struct hrtimer_clock_base *base)
{
	debug_activate(timer);

	base->cpu_base->active_bases |= 1 << base->index;

	timer->state = HRTIMER_STATE_ENQUEUED;

	return timerqueue_add(&base->active, &timer->node);
}

/*
 * enqueue_hrtimer - internal function to (re)start a timer
 *
 * The timer is inserted in expiry order. Insertion into the
 * red black tree is O(log(n)). Must hold the base lock.
 *
 * Returns 1 when the new timer is the leftmost timer in the tree.
 */
static int enqueue_hrtimer(struct hrtimer *timer,
			   struct hrtimer_clock_base *base)
{
	struct rb_node **link = &base->active.rb_node;
	struct rb_node *parent = NULL;
	struct hrtimer *entry;
	int leftmost = 1;

	debug_activate(timer);

	/*
	 * Find the right place in the rbtree:
	 */
	while (*link) {
		parent = *link;
		entry = rb_entry(parent, struct hrtimer, node);
		/*
		 * We dont care about collisions. Nodes with
		 * the same expiry time stay together.
		 */
		if (hrtimer_get_expires_tv64(timer) <
				hrtimer_get_expires_tv64(entry)) {
			link = &(*link)->rb_left;
		} else {
			link = &(*link)->rb_right;
			leftmost = 0;
		}
	}

	/*
	 * Insert the timer to the rbtree and check whether it
	 * replaces the first pending timer
	 */
	if (leftmost)
		base->first = &timer->node;

	rb_link_node(&timer->node, parent, link);
	rb_insert_color(&timer->node, &base->active);
	/*
	 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
	 * state of a possibly running callback.
	 */
	timer->state |= HRTIMER_STATE_ENQUEUED;

	return leftmost;
}