drivers/clk/msm/clock.c

/*
 * Copyright (C) 2007 Google, Inc.
 * Copyright (c) 2007-2017, The Linux Foundation. All rights reserved.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
 * GNU General Public License for more details.
 *
 */

#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/list.h>
#include <linux/regulator/consumer.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/clk/msm-clk-provider.h>
#include <linux/of_platform.h>
#include <linux/pm_opp.h>

#include <trace/events/power.h>
#include "clock.h"

struct handoff_clk {
	struct list_head list;
	struct clk *clk;
};
static LIST_HEAD(handoff_list);

struct handoff_vdd {
	struct list_head list;
	struct clk_vdd_class *vdd_class;
};
static LIST_HEAD(handoff_vdd_list);

static DEFINE_MUTEX(msm_clock_init_lock);
LIST_HEAD(orphan_clk_list);
static LIST_HEAD(clk_notifier_list);

/* Find the voltage level required for a given rate. */
int find_vdd_level(struct clk *clk, unsigned long rate)
{
	int level;

	for (level = 0; level < clk->num_fmax; level++)
		if (rate <= clk->fmax[level])
			break;

	if (level == clk->num_fmax) {
		pr_err("Rate %lu for %s is greater than highest Fmax\n", rate,
			clk->dbg_name);
		return -EINVAL;
	}

	return level;
}

/* Update voltage level given the current votes. */
static int update_vdd(struct clk_vdd_class *vdd_class)
{
	int level, rc = 0, i, ignore;
	struct regulator **r = vdd_class->regulator;
	int *uv = vdd_class->vdd_uv;
	int *ua = vdd_class->vdd_ua;
	int n_reg = vdd_class->num_regulators;
	int cur_lvl = vdd_class->cur_level;
	int max_lvl = vdd_class->num_levels - 1;
	int cur_base = cur_lvl * n_reg;
	int new_base;

	/* aggregate votes */
	for (level = max_lvl; level > 0; level--)
		if (vdd_class->level_votes[level])
			break;

	if (level == cur_lvl)
		return 0;

	max_lvl = max_lvl * n_reg;
	new_base = level * n_reg;
	for (i = 0; i < vdd_class->num_regulators; i++) {
		rc = regulator_set_voltage(r[i], uv[new_base + i],
			vdd_class->use_max_uV ? INT_MAX : uv[max_lvl + i]);
		if (rc)
			goto set_voltage_fail;

		if (ua) {
			rc = regulator_set_load(r[i], ua[new_base + i]);
			rc = rc > 0 ? 0 : rc;
			if (rc)
				goto set_mode_fail;
		}
		if (cur_lvl == 0 || cur_lvl == vdd_class->num_levels)
			rc = regulator_enable(r[i]);
		else if (level == 0)
			rc = regulator_disable(r[i]);
		if (rc)
			goto enable_disable_fail;
	}
	if (vdd_class->set_vdd && !vdd_class->num_regulators)
		rc = vdd_class->set_vdd(vdd_class, level);

	if (!rc)
		vdd_class->cur_level = level;

	return rc;

enable_disable_fail:
	/*
	 * set_optimum_mode could use voltage to derive mode.  Restore
	 * previous voltage setting for r[i] first.
	 */
	if (ua) {
		regulator_set_voltage(r[i], uv[cur_base + i],
			vdd_class->use_max_uV ? INT_MAX : uv[max_lvl + i]);
		regulator_set_load(r[i], ua[cur_base + i]);
	}

set_mode_fail:
	regulator_set_voltage(r[i], uv[cur_base + i],
			vdd_class->use_max_uV ? INT_MAX : uv[max_lvl + i]);

set_voltage_fail:
	for (i--; i >= 0; i--) {
		regulator_set_voltage(r[i], uv[cur_base + i],
			vdd_class->use_max_uV ? INT_MAX : uv[max_lvl + i]);
		if (ua)
			regulator_set_load(r[i], ua[cur_base + i]);
		if (cur_lvl == 0 || cur_lvl == vdd_class->num_levels)
			regulator_disable(r[i]);
		else if (level == 0)
			ignore = regulator_enable(r[i]);
	}
	return rc;
}

/* Vote for a voltage level. */
int vote_vdd_level(struct clk_vdd_class *vdd_class, int level)
{
	int rc;

	if (level >= vdd_class->num_levels)
		return -EINVAL;

	mutex_lock(&vdd_class->lock);
	vdd_class->level_votes[level]++;
	rc = update_vdd(vdd_class);
	if (rc)
		vdd_class->level_votes[level]--;
	mutex_unlock(&vdd_class->lock);

	return rc;
}

/* Remove vote for a voltage level. */
int unvote_vdd_level(struct clk_vdd_class *vdd_class, int level)
{
	int rc = 0;

	if (level >= vdd_class->num_levels)
		return -EINVAL;

	mutex_lock(&vdd_class->lock);
	if (WARN(!vdd_class->level_votes[level],
			"Reference counts are incorrect for %s level %d\n",
			vdd_class->class_name, level))
		goto out;
	vdd_class->level_votes[level]--;
	rc = update_vdd(vdd_class);
	if (rc)
		vdd_class->level_votes[level]++;
out:
	mutex_unlock(&vdd_class->lock);
	return rc;
}

/* Vote for a voltage level corresponding to a clock's rate. */
static int vote_rate_vdd(struct clk *clk, unsigned long rate)
{
	int level;

	if (!clk->vdd_class)
		return 0;

	level = find_vdd_level(clk, rate);
	if (level < 0)
		return level;

	return vote_vdd_level(clk->vdd_class, level);
}

/* Remove vote for a voltage level corresponding to a clock's rate. */
static void unvote_rate_vdd(struct clk *clk, unsigned long rate)
{
	int level;

	if (!clk->vdd_class)
		return;

	level = find_vdd_level(clk, rate);
	if (level < 0)
		return;

	unvote_vdd_level(clk->vdd_class, level);
}

/* Check if the rate is within the voltage limits of the clock. */
bool is_rate_valid(struct clk *clk, unsigned long rate)
{
	int level;

	if (!clk->vdd_class)
		return true;

	level = find_vdd_level(clk, rate);
	return level >= 0;
}

/**
 * __clk_pre_reparent() - Set up the new parent before switching to it and
 * prevent the enable state of the child clock from changing.
 * @c: The child clock that's going to switch parents
 * @new: The new parent that the child clock is going to switch to
 * @flags: Pointer to scratch space to save spinlock flags
 *
 * Cannot be called from atomic context.
 *
 * Use this API to set up the @new parent clock to be able to support the
 * current prepare and enable state of the child clock @c. Once the parent is
 * set up, the child clock can safely switch to it.
 *
 * The caller shall grab the prepare_lock of clock @c before calling this API
 * and only release it after calling __clk_post_reparent() for clock @c (or
 * if this API fails). This is necessary to prevent the prepare state of the
 * child clock @c from changing while the reparenting is in progress. Since
 * this API takes care of grabbing the enable lock of @c, only atomic
 * operation are allowed between calls to __clk_pre_reparent and
 * __clk_post_reparent()
 *
 * The scratch space pointed to by @flags should not be altered before
 * calling __clk_post_reparent() for clock @c.
 *
 * See also: __clk_post_reparent()
 */
int __clk_pre_reparent(struct clk *c, struct clk *new, unsigned long *flags)
{
	int rc;

	if (c->prepare_count) {
		rc = clk_prepare(new);
		if (rc)
			return rc;
	}

	spin_lock_irqsave(&c->lock, *flags);
	if (c->count) {
		rc = clk_enable(new);
		if (rc) {
			spin_unlock_irqrestore(&c->lock, *flags);
			clk_unprepare(new);
			return rc;
		}
	}
	return 0;
}

/**
 * __clk_post_reparent() - Release requirements on old parent after switching
 * away from it and allow changes to the child clock's enable state.
 * @c:   The child clock that switched parents
 * @old: The old parent that the child clock switched away from or the new
 *	 parent of a failed reparent attempt.
 * @flags: Pointer to scratch space where spinlock flags were saved
 *
 * Cannot be called from atomic context.
 *
 * This API works in tandem with __clk_pre_reparent. Use this API to
 * - Remove prepare and enable requirements from the @old parent after
 *   switching away from it
 * - Or, undo the effects of __clk_pre_reparent() after a failed attempt to
 *   change parents
 *
 * The caller shall release the prepare_lock of @c that was grabbed before
 * calling __clk_pre_reparent() only after this API is called (or if
 * __clk_pre_reparent() fails). This is necessary to prevent the prepare
 * state of the child clock @c from changing while the reparenting is in
 * progress. Since this API releases the enable lock of @c, the limit to
 * atomic operations set by __clk_pre_reparent() is no longer present.
 *
 * The scratch space pointed to by @flags shall not be altered since the call
 * to  __clk_pre_reparent() for clock @c.
 *
 * See also: __clk_pre_reparent()
 */
void __clk_post_reparent(struct clk *c, struct clk *old, unsigned long *flags)
{
	if (c->count)
		clk_disable(old);
	spin_unlock_irqrestore(&c->lock, *flags);

	if (c->prepare_count)
		clk_unprepare(old);
}

int clk_prepare(struct clk *clk)
{
	int ret = 0;
	struct clk *parent;

	if (!clk)
		return 0;
	if (IS_ERR(clk))
		return -EINVAL;

	mutex_lock(&clk->prepare_lock);
	if (clk->prepare_count == 0) {
		parent = clk->parent;

		ret = clk_prepare(parent);
		if (ret)
			goto out;
		ret = clk_prepare(clk->depends);
		if (ret)
			goto err_prepare_depends;

		ret = vote_rate_vdd(clk, clk->rate);
		if (ret)
			goto err_vote_vdd;
		if (clk->ops->prepare)
			ret = clk->ops->prepare(clk);
		if (ret)
			goto err_prepare_clock;
	}
	clk->prepare_count++;
out:
	mutex_unlock(&clk->prepare_lock);
	return ret;
err_prepare_clock:
	unvote_rate_vdd(clk, clk->rate);
err_vote_vdd:
	clk_unprepare(clk->depends);
err_prepare_depends:
	clk_unprepare(parent);
	goto out;
}
EXPORT_SYMBOL(clk_prepare);

/*
 * Standard clock functions defined in include/linux/clk.h
 */
int clk_enable(struct clk *clk)
{
	int ret = 0;
	unsigned long flags;
	struct clk *parent;
	const char *name;

	if (!clk)
		return 0;
	if (IS_ERR(clk))
		return -EINVAL;
	name = clk->dbg_name;

	spin_lock_irqsave(&clk->lock, flags);
	WARN(!clk->prepare_count,
			"%s: Don't call enable on unprepared clocks\n", name);
	if (clk->count == 0) {
		parent = clk->parent;

		ret = clk_enable(parent);
		if (ret)
			goto err_enable_parent;
		ret = clk_enable(clk->depends);
		if (ret)
			goto err_enable_depends;

		trace_clock_enable(name, 1, smp_processor_id());
		if (clk->ops->enable)
			ret = clk->ops->enable(clk);
		if (ret)
			goto err_enable_clock;
	}
	clk->count++;
	spin_unlock_irqrestore(&clk->lock, flags);

	return 0;

err_enable_clock:
	clk_disable(clk->depends);
err_enable_depends:
	clk_disable(parent);
err_enable_parent:
	spin_unlock_irqrestore(&clk->lock, flags);
	return ret;
}
EXPORT_SYMBOL(clk_enable);

void clk_disable(struct clk *clk)
{
	const char *name;
	unsigned long flags;

	if (IS_ERR_OR_NULL(clk))
		return;
	name = clk->dbg_name;

	spin_lock_irqsave(&clk->lock, flags);
	WARN(!clk->prepare_count,
			"%s: Never called prepare or calling disable after unprepare\n",
			name);
	if (WARN(clk->count == 0, "%s is unbalanced", name))
		goto out;
	if (clk->count == 1) {
		struct clk *parent = clk->parent;

		trace_clock_disable(name, 0, smp_processor_id());
		if (clk->ops->disable)
			clk->ops->disable(clk);
		clk_disable(clk->depends);
		clk_disable(parent);
	}
	clk->count--;
out:
	spin_unlock_irqrestore(&clk->lock, flags);
}
EXPORT_SYMBOL(clk_disable);

void clk_unprepare(struct clk *clk)
{
	const char *name;

	if (IS_ERR_OR_NULL(clk))
		return;
	name = clk->dbg_name;

	mutex_lock(&clk->prepare_lock);
	if (WARN(!clk->prepare_count, "%s is unbalanced (prepare)", name))
		goto out;
	if (clk->prepare_count == 1) {
		struct clk *parent = clk->parent;

		WARN(clk->count,
			"%s: Don't call unprepare when the clock is enabled\n",
			name);

		if (clk->ops->unprepare)
			clk->ops->unprepare(clk);
		unvote_rate_vdd(clk, clk->rate);
		clk_unprepare(clk->depends);
		clk_unprepare(parent);
	}
	clk->prepare_count--;
out:
	mutex_unlock(&clk->prepare_lock);
}
EXPORT_SYMBOL(clk_unprepare);

int clk_reset(struct clk *clk, enum clk_reset_action action)
{
	if (IS_ERR_OR_NULL(clk))
		return -EINVAL;

	if (!clk->ops->reset)
		return -EINVAL;

	return clk->ops->reset(clk, action);
}
EXPORT_SYMBOL(clk_reset);

/**
 * __clk_notify - call clk notifier chain
 * @clk: struct clk * that is changing rate
 * @msg: clk notifier type (see include/linux/clk.h)
 * @old_rate: old clk rate
 * @new_rate: new clk rate
 *
 * Triggers a notifier call chain on the clk rate-change notification
 * for 'clk'.  Passes a pointer to the struct clk and the previous
 * and current rates to the notifier callback.  Intended to be called by
 * internal clock code only.  Returns NOTIFY_DONE from the last driver
 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
 * a driver returns that.
 */
static int __clk_notify(struct clk *clk, unsigned long msg,
		unsigned long old_rate, unsigned long new_rate)
{
	struct msm_clk_notifier *cn;
	struct msm_clk_notifier_data cnd;
	int ret = NOTIFY_DONE;

	cnd.clk = clk;
	cnd.old_rate = old_rate;
	cnd.new_rate = new_rate;

	list_for_each_entry(cn, &clk_notifier_list, node) {
		if (cn->clk == clk) {
			ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
					&cnd);
			break;
		}
	}

	return ret;
}

/*
 * clk rate change notifiers
 *
 * Note - The following notifier functionality is a verbatim copy
 * of the implementation in the common clock framework, copied here
 * until MSM switches to the common clock framework.
 */

/**
 * msm_clk_notif_register - add a clk rate change notifier
 * @clk: struct clk * to watch
 * @nb: struct notifier_block * with callback info
 *
 * Request notification when clk's rate changes.  This uses an SRCU
 * notifier because we want it to block and notifier unregistrations are
 * uncommon.  The callbacks associated with the notifier must not
 * re-enter into the clk framework by calling any top-level clk APIs;
 * this will cause a nested prepare_lock mutex.
 *
 * Pre-change notifier callbacks will be passed the current, pre-change
 * rate of the clk via struct msm_clk_notifier_data.old_rate.  The new,
 * post-change rate of the clk is passed via struct
 * msm_clk_notifier_data.new_rate.
 *
 * Post-change notifiers will pass the now-current, post-change rate of
 * the clk in both struct msm_clk_notifier_data.old_rate and struct
 * msm_clk_notifier_data.new_rate.
 *
 * Abort-change notifiers are effectively the opposite of pre-change
 * notifiers: the original pre-change clk rate is passed in via struct
 * msm_clk_notifier_data.new_rate and the failed post-change rate is passed
 * in via struct msm_clk_notifier_data.old_rate.
 *
 * msm_clk_notif_register() must be called from non-atomic context.
 * Returns -EINVAL if called with null arguments, -ENOMEM upon
 * allocation failure; otherwise, passes along the return value of
 * srcu_notifier_chain_register().
 */
int msm_clk_notif_register(struct clk *clk, struct notifier_block *nb)
{
	struct msm_clk_notifier *cn;
	int ret = -ENOMEM;

	if (!clk || !nb)
		return -EINVAL;

	mutex_lock(&clk->prepare_lock);

	/* search the list of notifiers for this clk */
	list_for_each_entry(cn, &clk_notifier_list, node)
		if (cn->clk == clk)
			break;

	/* if clk wasn't in the notifier list, allocate new clk_notifier */
	if (cn->clk != clk) {
		cn = kzalloc(sizeof(struct msm_clk_notifier), GFP_KERNEL);
		if (!cn)
			goto out;

		cn->clk = clk;
		srcu_init_notifier_head(&cn->notifier_head);

		list_add(&cn->node, &clk_notifier_list);
	}

	ret = srcu_notifier_chain_register(&cn->notifier_head, nb);

	clk->notifier_count++;

out:
	mutex_unlock(&clk->prepare_lock);

	return ret;
}

/**
 * msm_clk_notif_unregister - remove a clk rate change notifier
 * @clk: struct clk *
 * @nb: struct notifier_block * with callback info
 *
 * Request no further notification for changes to 'clk' and frees memory
 * allocated in msm_clk_notifier_register.
 *
 * Returns -EINVAL if called with null arguments; otherwise, passes
 * along the return value of srcu_notifier_chain_unregister().
 */
int msm_clk_notif_unregister(struct clk *clk, struct notifier_block *nb)
{
	struct msm_clk_notifier *cn = NULL;
	int ret = -EINVAL;

	if (!clk || !nb)
		return -EINVAL;

	mutex_lock(&clk->prepare_lock);

	list_for_each_entry(cn, &clk_notifier_list, node)
		if (cn->clk == clk)
			break;

	if (cn->clk == clk) {
		ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);

		clk->notifier_count--;

		/* XXX the notifier code should handle this better */
		if (!cn->notifier_head.head) {
			srcu_cleanup_notifier_head(&cn->notifier_head);
			list_del(&cn->node);
			kfree(cn);
		}

	} else {
		ret = -ENOENT;
	}

	mutex_unlock(&clk->prepare_lock);

	return ret;
}

unsigned long clk_get_rate(struct clk *clk)
{
	if (IS_ERR_OR_NULL(clk))
		return 0;

	if (!clk->ops->get_rate)
		return clk->rate;

	return clk->ops->get_rate(clk);
}
EXPORT_SYMBOL(clk_get_rate);

int clk_set_rate(struct clk *clk, unsigned long rate)
{
	unsigned long start_rate;
	int rc = 0;
	const char *name;

	if (IS_ERR_OR_NULL(clk))
		return -EINVAL;
	name = clk->dbg_name;

	if (!is_rate_valid(clk, rate))
		return -EINVAL;

	mutex_lock(&clk->prepare_lock);

	/* Return early if the rate isn't going to change */
	if (clk->rate == rate && !(clk->flags & CLKFLAG_NO_RATE_CACHE))
		goto out;

	if (!clk->ops->set_rate) {
		rc = -EINVAL;
		goto out;
	}

	trace_clock_set_rate(name, rate, raw_smp_processor_id());

	start_rate = clk->rate;

	if (clk->notifier_count)
		__clk_notify(clk, PRE_RATE_CHANGE, clk->rate, rate);

	if (clk->ops->pre_set_rate) {
		rc = clk->ops->pre_set_rate(clk, rate);
		if (rc)
			goto abort_set_rate;
	}

	/* Enforce vdd requirements for target frequency. */
	if (clk->prepare_count) {
		rc = vote_rate_vdd(clk, rate);
		if (rc)
			goto err_vote_vdd;
	}

	rc = clk->ops->set_rate(clk, rate);
	if (rc)
		goto err_set_rate;
	clk->rate = rate;

	/* Release vdd requirements for starting frequency. */
	if (clk->prepare_count)
		unvote_rate_vdd(clk, start_rate);

	if (clk->ops->post_set_rate)
		clk->ops->post_set_rate(clk, start_rate);

	if (clk->notifier_count)
		__clk_notify(clk, POST_RATE_CHANGE, start_rate, clk->rate);

	trace_clock_set_rate_complete(name, clk->rate, raw_smp_processor_id());
out:
	mutex_unlock(&clk->prepare_lock);
	return rc;

abort_set_rate:
	__clk_notify(clk, ABORT_RATE_CHANGE, clk->rate, rate);
err_set_rate:
	if (clk->prepare_count)
		unvote_rate_vdd(clk, rate);
err_vote_vdd:
	/* clk->rate is still the old rate. So, pass the new rate instead. */
	if (clk->ops->post_set_rate)
		clk->ops->post_set_rate(clk, rate);
	goto out;
}
EXPORT_SYMBOL(clk_set_rate);

long clk_round_rate(struct clk *clk, unsigned long rate)
{
	long rrate;
	unsigned long fmax = 0, i;

	if (IS_ERR_OR_NULL(clk))
		return -EINVAL;

	for (i = 0; i < clk->num_fmax; i++)
		fmax = max(fmax, clk->fmax[i]);
	if (!fmax)
		fmax = ULONG_MAX;
	rate = min(rate, fmax);

	if (clk->ops->round_rate)
		rrate = clk->ops->round_rate(clk, rate);
	else if (clk->rate)
		rrate = clk->rate;
	else
		return -EINVAL;

	if (rrate > fmax)
		return -EINVAL;
	return rrate;
}
EXPORT_SYMBOL(clk_round_rate);

int clk_set_max_rate(struct clk *clk, unsigned long rate)
{
	if (IS_ERR_OR_NULL(clk))
		return -EINVAL;

	if (!clk->ops->set_max_rate)
		return -EINVAL;

	return clk->ops->set_max_rate(clk, rate);
}
EXPORT_SYMBOL(clk_set_max_rate);

int parent_to_src_sel(struct clk_src *parents, int num_parents, struct clk *p)
{
	int i;

	for (i = 0; i < num_parents; i++) {
		if (parents[i].src == p)
			return parents[i].sel;
	}

	return -EINVAL;
}
EXPORT_SYMBOL(parent_to_src_sel);

int clk_get_parent_sel(struct clk *c, struct clk *parent)
{
	return parent_to_src_sel(c->parents, c->num_parents, parent);
}
EXPORT_SYMBOL(clk_get_parent_sel);

int clk_set_parent(struct clk *clk, struct clk *parent)
{
	int rc = 0;

	if (IS_ERR_OR_NULL(clk))
		return -EINVAL;

	if (!clk->ops->set_parent && clk->parent == parent)
		return 0;

	if (!clk->ops->set_parent)
		return -EINVAL;

	mutex_lock(&clk->prepare_lock);
	if (clk->parent == parent && !(clk->flags & CLKFLAG_NO_RATE_CACHE))
		goto out;
	rc = clk->ops->set_parent(clk, parent);
out:
	mutex_unlock(&clk->prepare_lock);

	return rc;
}
EXPORT_SYMBOL(clk_set_parent);

struct clk *clk_get_parent(struct clk *clk)
{
	if (IS_ERR_OR_NULL(clk))
		return NULL;

	return clk->parent;
}
EXPORT_SYMBOL(clk_get_parent);

int clk_set_flags(struct clk *clk, unsigned long flags)
{
	if (IS_ERR_OR_NULL(clk))
		return -EINVAL;
	if (!clk->ops->set_flags)
		return -EINVAL;

	return clk->ops->set_flags(clk, flags);
}
EXPORT_SYMBOL(clk_set_flags);

int clk_set_duty_cycle(struct clk *clk, u32 numerator, u32 denominator)
{
	if (IS_ERR_OR_NULL(clk))
		return -EINVAL;

	if (numerator > denominator) {
		pr_err("Numerator cannot be > denominator\n");
		return -EINVAL;
	}

	if (!denominator) {
		pr_err("Denominator can not be Zero\n");
		return -EINVAL;
	}

	if (!clk->ops->set_duty_cycle)
		return -EINVAL;

	return clk->ops->set_duty_cycle(clk, numerator, denominator);
}
EXPORT_SYMBOL(clk_set_duty_cycle);

static LIST_HEAD(initdata_list);

static void init_sibling_lists(struct clk_lookup *clock_tbl, size_t num_clocks)
{
	struct clk *clk, *parent;
	unsigned long n;

	for (n = 0; n < num_clocks; n++) {
		clk = clock_tbl[n].clk;
		parent = clk->parent;
		if (parent && list_empty(&clk->siblings))
			list_add(&clk->siblings, &parent->children);
	}
}

static void vdd_class_init(struct clk_vdd_class *vdd)
{
	struct handoff_vdd *v;

	if (!vdd)
		return;

	if (vdd->skip_handoff)
		return;

	list_for_each_entry(v, &handoff_vdd_list, list) {
		if (v->vdd_class == vdd)
			return;
	}

	pr_debug("voting for vdd_class %s\n", vdd->class_name);
	if (vote_vdd_level(vdd, vdd->num_levels - 1))
		pr_err("failed to vote for %s\n", vdd->class_name);

	v = kmalloc(sizeof(*v), GFP_KERNEL);
	if (!v)
		return;

	v->vdd_class = vdd;
	list_add_tail(&v->list, &handoff_vdd_list);
}

static int __handoff_clk(struct clk *clk)
{
	enum handoff state = HANDOFF_DISABLED_CLK;
	struct handoff_clk *h = NULL;
	int rc, i;

	if (clk == NULL || clk->flags & CLKFLAG_INIT_DONE ||
	    clk->flags & CLKFLAG_SKIP_HANDOFF)
		return 0;

	if (clk->flags & CLKFLAG_INIT_ERR)
		return -ENXIO;

	if (clk->flags & CLKFLAG_EPROBE_DEFER)
		return -EPROBE_DEFER;

	/* Handoff any 'depends' clock first. */
	rc = __handoff_clk(clk->depends);
	if (rc)
		goto err;

	/*
	 * Handoff functions for the parent must be called before the
	 * children can be handed off. Without handing off the parents and
	 * knowing their rate and state (on/off), it's impossible to figure
	 * out the rate and state of the children.
	 */
	if (clk->ops->get_parent)
		clk->parent = clk->ops->get_parent(clk);

	if (IS_ERR(clk->parent)) {
		rc = PTR_ERR(clk->parent);
		goto err;
	}

	rc = __handoff_clk(clk->parent);
	if (rc)
		goto err;

	for (i = 0; i < clk->num_parents; i++) {
		rc = __handoff_clk(clk->parents[i].src);
		if (rc)
			goto err;
	}

	if (clk->ops->handoff)
		state = clk->ops->handoff(clk);

	if (state == HANDOFF_ENABLED_CLK) {

		h = kmalloc(sizeof(*h), GFP_KERNEL);
		if (!h) {
			rc = -ENOMEM;
			goto err;
		}

		rc = clk_prepare_enable(clk->parent);
		if (rc)
			goto err;

		rc = clk_prepare_enable(clk->depends);
		if (rc)
			goto err_depends;

		rc = vote_rate_vdd(clk, clk->rate);
		WARN(rc, "%s unable to vote for voltage!\n", clk->dbg_name);

		clk->count = 1;
		clk->prepare_count = 1;
		h->clk = clk;
		list_add_tail(&h->list, &handoff_list);

		pr_debug("Handed off %s rate=%lu\n", clk->dbg_name, clk->rate);
	}

	if (clk->init_rate && clk_set_rate(clk, clk->init_rate))
		pr_err("failed to set an init rate of %lu on %s\n",
			clk->init_rate, clk->dbg_name);
	if (clk->always_on && clk_prepare_enable(clk))
		pr_err("failed to enable always-on clock %s\n",
			clk->dbg_name);

	clk->flags |= CLKFLAG_INIT_DONE;
	/* if the clk is on orphan list, remove it */
	list_del_init(&clk->list);
	clock_debug_register(clk);

	return 0;

err_depends:
	clk_disable_unprepare(clk->parent);
err:
	kfree(h);
	if (rc == -EPROBE_DEFER) {
		clk->flags |= CLKFLAG_EPROBE_DEFER;
		if (list_empty(&clk->list))
			list_add_tail(&clk->list, &orphan_clk_list);
	} else {
		pr_err("%s handoff failed (%d)\n", clk->dbg_name, rc);
		clk->flags |= CLKFLAG_INIT_ERR;
	}
	return rc;
}

/**
 * msm_clock_register() - Register additional clock tables
 * @table: Table of clocks
 * @size: Size of @table
 *
 * Upon return, clock APIs may be used to control clocks registered using this
 * function.
 */
int msm_clock_register(struct clk_lookup *table, size_t size)
{
	int n = 0, rc;
	struct clk *c, *safe;
	bool found_more_clks;

	mutex_lock(&msm_clock_init_lock);

	init_sibling_lists(table, size);

	/*
	 * Enable regulators and temporarily set them up at maximum voltage.
	 * Once all the clocks have made their respective vote, remove this
	 * temporary vote. The removing of the temporary vote is done at
	 * late_init, by which time we assume all the clocks would have been
	 * handed off.
	 */
	for (n = 0; n < size; n++)
		vdd_class_init(table[n].clk->vdd_class);

	/*
	 * Detect and preserve initial clock state until clock_late_init() or
	 * a driver explicitly changes it, whichever is first.
	 */

	for (n = 0; n < size; n++)
		__handoff_clk(table[n].clk);

	/* maintain backwards compatibility */
	if (table[0].con_id || table[0].dev_id)
		clkdev_add_table(table, size);

	do {
		found_more_clks = false;
		/* clear cached __handoff_clk return values */
		list_for_each_entry_safe(c, safe, &orphan_clk_list, list)
			c->flags &= ~CLKFLAG_EPROBE_DEFER;

		list_for_each_entry_safe(c, safe, &orphan_clk_list, list) {
			rc = __handoff_clk(c);
			if (!rc)
				found_more_clks = true;
		}
	} while (found_more_clks);

	mutex_unlock(&msm_clock_init_lock);

	return 0;
}
EXPORT_SYMBOL(msm_clock_register);

struct of_msm_provider_data {
	struct clk_lookup *table;
	size_t size;
};

static struct clk *of_clk_src_get(struct of_phandle_args *clkspec,
				  void *data)
{
	struct of_msm_provider_data *ofdata = data;
	int n;

	for (n = 0; n < ofdata->size; n++) {
		if (clkspec->args[0] == ofdata->table[n].of_idx)
			return ofdata->table[n].clk;
	}
	return ERR_PTR(-ENOENT);
}

#define MAX_LEN_OPP_HANDLE	50
#define LEN_OPP_HANDLE		16
#define LEN_OPP_VCORNER_HANDLE	22

static struct device **derive_device_list(struct clk *clk,
					struct device_node *np,
					char *clk_handle_name, int len)
{
	int j, count, cpu;
	struct platform_device *pdev;
	struct device_node *dev_node;
	struct device **device_list;

	count = len/sizeof(u32);
	device_list = kmalloc_array(count, sizeof(struct device *),
							GFP_KERNEL);
	if (!device_list)
		return ERR_PTR(-ENOMEM);

	for (j = 0; j < count; j++) {
		device_list[j] = NULL;
		dev_node = of_parse_phandle(np, clk_handle_name, j);
		if (!dev_node) {
			pr_err("Unable to get device_node pointer for %s opp-handle (%s)\n",
					clk->dbg_name, clk_handle_name);
			goto err_parse_phandle;
		}

		for_each_possible_cpu(cpu) {
			if (of_get_cpu_node(cpu, NULL) == dev_node)
				device_list[j] = get_cpu_device(cpu);
		}

		if (device_list[j])
			continue;

		pdev = of_find_device_by_node(dev_node);
		if (!pdev) {
			pr_err("Unable to find platform_device node for %s opp-handle\n",
						clk->dbg_name);
			goto err_parse_phandle;
		}
		device_list[j] = &pdev->dev;
	}
	return device_list;
err_parse_phandle:
	kfree(device_list);
	return ERR_PTR(-EINVAL);
}

static int get_voltage(struct clk *clk, unsigned long rate,
				int store_vcorner, int n)
{
	struct clk_vdd_class *vdd;
	int uv, level, corner;

	/*
	 * Use the first regulator in the vdd class
	 * for the OPP table.
	 */
	vdd = clk->vdd_class;
	if (vdd->num_regulators > 1) {
		corner = vdd->vdd_uv[vdd->num_regulators * n];
	} else {
		level = find_vdd_level(clk, rate);
		if (level < 0) {
			pr_err("Could not find vdd level\n");
			return -EINVAL;
		}
		corner = vdd->vdd_uv[level];
	}

	if (!corner) {
		pr_err("%s: Unable to find vdd level for rate %lu\n",
					clk->dbg_name, rate);
		return -EINVAL;
	}

	if (store_vcorner) {
		uv = corner;
		return uv;
	}

	uv = regulator_list_corner_voltage(vdd->regulator[0], corner);
	if (uv < 0) {
		pr_err("%s: no uv for corner %d - err: %d\n",
				clk->dbg_name, corner, uv);
		return uv;
	}
	return uv;
}

static int add_and_print_opp(struct clk *clk, struct device **device_list,
				int count, unsigned long rate, int uv, int n)
{
	int j, ret = 0;

	for (j = 0; j < count; j++) {
		ret = dev_pm_opp_add(device_list[j], rate, uv);
		if (ret) {
			pr_err("%s: couldn't add OPP for %lu - err: %d\n",
						clk->dbg_name, rate, ret);
			return ret;
		}
		if (n == 1 || n == clk->num_fmax - 1 ||
					rate == clk_round_rate(clk, INT_MAX))
			pr_info("%s: set OPP pair(%lu Hz: %u uV) on %s\n",
						clk->dbg_name, rate, uv,
						dev_name(device_list[j]));
	}
	return ret;
}

static void populate_clock_opp_table(struct device_node *np,
			struct clk_lookup *table, size_t size)
{
	struct device **device_list;
	struct clk *clk;
	char clk_handle_name[MAX_LEN_OPP_HANDLE];
	char clk_store_volt_corner[MAX_LEN_OPP_HANDLE];
	size_t i;
	int n, len, count, uv = 0;
	unsigned long rate, ret = 0;
	bool store_vcorner;

	/* Iterate across all clocks in the clock controller */
	for (i = 0; i < size; i++) {
		n = 1;
		rate = 0;

		store_vcorner = false;
		clk = table[i].clk;
		if (!clk || !clk->num_fmax || clk->opp_table_populated)
			continue;

		if (strlen(clk->dbg_name) + LEN_OPP_HANDLE
					< MAX_LEN_OPP_HANDLE) {
			ret = snprintf(clk_handle_name,
					ARRAY_SIZE(clk_handle_name),
					"qcom,%s-opp-handle", clk->dbg_name);
			if (ret < strlen(clk->dbg_name) + LEN_OPP_HANDLE) {
				pr_err("Failed to hold clk_handle_name\n");
				continue;
			}
		} else {
			pr_err("clk name (%s) too large to fit in clk_handle_name\n",
							clk->dbg_name);
			continue;
		}

		if (strlen(clk->dbg_name) + LEN_OPP_VCORNER_HANDLE
					< MAX_LEN_OPP_HANDLE) {
			ret = snprintf(clk_store_volt_corner,
				ARRAY_SIZE(clk_store_volt_corner),
				"qcom,%s-opp-store-vcorner", clk->dbg_name);
			if (ret < strlen(clk->dbg_name) +
						LEN_OPP_VCORNER_HANDLE) {
				pr_err("Failed to hold clk_store_volt_corner\n");
				continue;
			}
		} else {
			pr_err("clk name (%s) too large to fit in clk_store_volt_corner\n",
							clk->dbg_name);
			continue;
		}

		if (!of_find_property(np, clk_handle_name, &len)) {
			pr_debug("Unable to find %s\n", clk_handle_name);
			if (!of_find_property(np, clk_store_volt_corner,
								&len)) {
				pr_debug("Unable to find %s\n",
						clk_store_volt_corner);
				continue;
			} else {
				store_vcorner = true;
				device_list = derive_device_list(clk, np,
						clk_store_volt_corner, len);
			}
		} else
			device_list = derive_device_list(clk, np,
						clk_handle_name, len);
		if (IS_ERR_OR_NULL(device_list)) {
			pr_err("Failed to fill device_list\n");
			continue;
		}

		count = len/sizeof(u32);
		while (1) {
			/*
			 * Calling clk_round_rate will not work for all clocks
			 * (eg. mux_div). Use their fmax values instead to get
			 *  list of all available frequencies.
			 */
			if (clk->ops->list_rate) {
				ret = clk_round_rate(clk, rate + 1);
				if (ret < 0) {
					pr_err("clk_round_rate failed for %s\n",
							clk->dbg_name);
					goto err_round_rate;
				}
				/*
				 * If clk_round_rate give the same value on
				 * consecutive iterations, exit loop since
				 * we're at the maximum clock frequency.
				 */
				if (rate == ret)
					break;
				rate = ret;
			} else {
				if (n < clk->num_fmax)
					rate = clk->fmax[n];
				else
					break;
			}

			uv = get_voltage(clk, rate, store_vcorner, n);
			if (uv < 0)
				goto err_round_rate;

			ret = add_and_print_opp(clk, device_list, count,
							rate, uv, n);
			if (ret)
				goto err_round_rate;

			n++;
		}
err_round_rate:
		/* If OPP table population was successful, set the flag */
		if (uv >= 0 && ret >= 0)
			clk->opp_table_populated = true;
		kfree(device_list);
	}
}

/**
 * of_msm_clock_register() - Register clock tables with clkdev and with the
 *			     clock DT framework
 * @table: Table of clocks
 * @size: Size of @table
 * @np: Device pointer corresponding to the clock-provider device
 *
 * Upon return, clock APIs may be used to control clocks registered using this
 * function.
 */
int of_msm_clock_register(struct device_node *np, struct clk_lookup *table,
				size_t size)
{
	int ret = 0;
	struct of_msm_provider_data *data;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->table = table;
	data->size = size;

	ret = of_clk_add_provider(np, of_clk_src_get, data);
	if (ret) {
		kfree(data);
		return -ENOMEM;
	}

	populate_clock_opp_table(np, table, size);
	return msm_clock_register(table, size);
}
EXPORT_SYMBOL(of_msm_clock_register);

/**
 * msm_clock_init() - Register and initialize a clock driver
 * @data: Driver-specific clock initialization data
 *
 * Upon return from this call, clock APIs may be used to control
 * clocks registered with this API.
 */
int __init msm_clock_init(struct clock_init_data *data)
{
	if (!data)
		return -EINVAL;

	if (data->pre_init)
		data->pre_init();

	mutex_lock(&msm_clock_init_lock);
	if (data->late_init)
		list_add(&data->list, &initdata_list);
	mutex_unlock(&msm_clock_init_lock);

	msm_clock_register(data->table, data->size);

	if (data->post_init)
		data->post_init();

	return 0;
}

static int __init clock_late_init(void)
{
	struct handoff_clk *h, *h_temp;
	struct handoff_vdd *v, *v_temp;
	struct clock_init_data *initdata, *initdata_temp;
	int ret = 0;

	pr_info("%s: Removing enables held for handed-off clocks\n", __func__);

	mutex_lock(&msm_clock_init_lock);

	list_for_each_entry_safe(initdata, initdata_temp,
					&initdata_list, list) {
		ret = initdata->late_init();
		if (ret)
			pr_err("%s: %pS failed late_init.\n", __func__,
				initdata);
	}

	list_for_each_entry_safe(h, h_temp, &handoff_list, list) {
		clk_disable_unprepare(h->clk);
		list_del(&h->list);
		kfree(h);
	}

	list_for_each_entry_safe(v, v_temp, &handoff_vdd_list, list) {
		unvote_vdd_level(v->vdd_class, v->vdd_class->num_levels - 1);
		list_del(&v->list);
		kfree(v);
	}

	mutex_unlock(&msm_clock_init_lock);

	return ret;
}
/* clock_late_init should run only after all deferred probing
 * (excluding DLKM probes) has completed.
 */
late_initcall_sync(clock_late_init);