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linux/drivers/clk/clk.c

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/*
* Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
* Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Standard functionality for the common clock API. See Documentation/clk.txt
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/clk/clk-conf.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/clkdev.h>
#include "clk.h"
static DEFINE_SPINLOCK(enable_lock);
static DEFINE_MUTEX(prepare_lock);
static struct task_struct *prepare_owner;
static struct task_struct *enable_owner;
static int prepare_refcnt;
static int enable_refcnt;
static HLIST_HEAD(clk_root_list);
static HLIST_HEAD(clk_orphan_list);
static LIST_HEAD(clk_notifier_list);
/*** private data structures ***/
struct clk_core {
const char *name;
const struct clk_ops *ops;
struct clk_hw *hw;
struct module *owner;
struct clk_core *parent;
const char **parent_names;
struct clk_core **parents;
u8 num_parents;
u8 new_parent_index;
unsigned long rate;
unsigned long req_rate;
unsigned long new_rate;
struct clk_core *new_parent;
struct clk_core *new_child;
unsigned long flags;
bool orphan;
unsigned int enable_count;
unsigned int prepare_count;
unsigned long min_rate;
unsigned long max_rate;
unsigned long accuracy;
int phase;
struct hlist_head children;
struct hlist_node child_node;
struct hlist_head clks;
unsigned int notifier_count;
#ifdef CONFIG_DEBUG_FS
struct dentry *dentry;
struct hlist_node debug_node;
#endif
struct kref ref;
};
#define CREATE_TRACE_POINTS
#include <trace/events/clk.h>
struct clk {
struct clk_core *core;
const char *dev_id;
const char *con_id;
unsigned long min_rate;
unsigned long max_rate;
struct hlist_node clks_node;
};
/*** locking ***/
static void clk_prepare_lock(void)
{
if (!mutex_trylock(&prepare_lock)) {
if (prepare_owner == current) {
prepare_refcnt++;
return;
}
mutex_lock(&prepare_lock);
}
WARN_ON_ONCE(prepare_owner != NULL);
WARN_ON_ONCE(prepare_refcnt != 0);
prepare_owner = current;
prepare_refcnt = 1;
}
static void clk_prepare_unlock(void)
{
WARN_ON_ONCE(prepare_owner != current);
WARN_ON_ONCE(prepare_refcnt == 0);
if (--prepare_refcnt)
return;
prepare_owner = NULL;
mutex_unlock(&prepare_lock);
}
static unsigned long clk_enable_lock(void)
__acquires(enable_lock)
{
unsigned long flags;
if (!spin_trylock_irqsave(&enable_lock, flags)) {
if (enable_owner == current) {
enable_refcnt++;
__acquire(enable_lock);
return flags;
}
spin_lock_irqsave(&enable_lock, flags);
}
WARN_ON_ONCE(enable_owner != NULL);
WARN_ON_ONCE(enable_refcnt != 0);
enable_owner = current;
enable_refcnt = 1;
return flags;
}
static void clk_enable_unlock(unsigned long flags)
__releases(enable_lock)
{
WARN_ON_ONCE(enable_owner != current);
WARN_ON_ONCE(enable_refcnt == 0);
if (--enable_refcnt) {
__release(enable_lock);
return;
}
enable_owner = NULL;
spin_unlock_irqrestore(&enable_lock, flags);
}
static bool clk_core_is_prepared(struct clk_core *core)
{
/*
* .is_prepared is optional for clocks that can prepare
* fall back to software usage counter if it is missing
*/
if (!core->ops->is_prepared)
return core->prepare_count;
return core->ops->is_prepared(core->hw);
}
static bool clk_core_is_enabled(struct clk_core *core)
{
/*
* .is_enabled is only mandatory for clocks that gate
* fall back to software usage counter if .is_enabled is missing
*/
if (!core->ops->is_enabled)
return core->enable_count;
return core->ops->is_enabled(core->hw);
}
/*** helper functions ***/
const char *__clk_get_name(const struct clk *clk)
{
return !clk ? NULL : clk->core->name;
}
EXPORT_SYMBOL_GPL(__clk_get_name);
const char *clk_hw_get_name(const struct clk_hw *hw)
{
return hw->core->name;
}
EXPORT_SYMBOL_GPL(clk_hw_get_name);
struct clk_hw *__clk_get_hw(struct clk *clk)
{
return !clk ? NULL : clk->core->hw;
}
EXPORT_SYMBOL_GPL(__clk_get_hw);
unsigned int clk_hw_get_num_parents(const struct clk_hw *hw)
{
return hw->core->num_parents;
}
EXPORT_SYMBOL_GPL(clk_hw_get_num_parents);
struct clk_hw *clk_hw_get_parent(const struct clk_hw *hw)
{
return hw->core->parent ? hw->core->parent->hw : NULL;
}
EXPORT_SYMBOL_GPL(clk_hw_get_parent);
static struct clk_core *__clk_lookup_subtree(const char *name,
struct clk_core *core)
{
struct clk_core *child;
struct clk_core *ret;
if (!strcmp(core->name, name))
return core;
hlist_for_each_entry(child, &core->children, child_node) {
ret = __clk_lookup_subtree(name, child);
if (ret)
return ret;
}
return NULL;
}
static struct clk_core *clk_core_lookup(const char *name)
{
struct clk_core *root_clk;
struct clk_core *ret;
if (!name)
return NULL;
/* search the 'proper' clk tree first */
hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
ret = __clk_lookup_subtree(name, root_clk);
if (ret)
return ret;
}
/* if not found, then search the orphan tree */
hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
ret = __clk_lookup_subtree(name, root_clk);
if (ret)
return ret;
}
return NULL;
}
static struct clk_core *clk_core_get_parent_by_index(struct clk_core *core,
u8 index)
{
if (!core || index >= core->num_parents)
return NULL;
if (!core->parents[index])
core->parents[index] =
clk_core_lookup(core->parent_names[index]);
return core->parents[index];
}
struct clk_hw *
clk_hw_get_parent_by_index(const struct clk_hw *hw, unsigned int index)
{
struct clk_core *parent;
parent = clk_core_get_parent_by_index(hw->core, index);
return !parent ? NULL : parent->hw;
}
EXPORT_SYMBOL_GPL(clk_hw_get_parent_by_index);
unsigned int __clk_get_enable_count(struct clk *clk)
{
return !clk ? 0 : clk->core->enable_count;
}
static unsigned long clk_core_get_rate_nolock(struct clk_core *core)
{
unsigned long ret;
if (!core) {
ret = 0;
goto out;
}
ret = core->rate;
if (!core->num_parents)
goto out;
if (!core->parent)
ret = 0;
out:
return ret;
}
unsigned long clk_hw_get_rate(const struct clk_hw *hw)
{
return clk_core_get_rate_nolock(hw->core);
}
EXPORT_SYMBOL_GPL(clk_hw_get_rate);
static unsigned long __clk_get_accuracy(struct clk_core *core)
{
if (!core)
return 0;
return core->accuracy;
}
unsigned long __clk_get_flags(struct clk *clk)
{
return !clk ? 0 : clk->core->flags;
}
EXPORT_SYMBOL_GPL(__clk_get_flags);
unsigned long clk_hw_get_flags(const struct clk_hw *hw)
{
return hw->core->flags;
}
EXPORT_SYMBOL_GPL(clk_hw_get_flags);
bool clk_hw_is_prepared(const struct clk_hw *hw)
{
return clk_core_is_prepared(hw->core);
}
bool clk_hw_is_enabled(const struct clk_hw *hw)
{
return clk_core_is_enabled(hw->core);
}
bool __clk_is_enabled(struct clk *clk)
{
if (!clk)
return false;
return clk_core_is_enabled(clk->core);
}
EXPORT_SYMBOL_GPL(__clk_is_enabled);
static bool mux_is_better_rate(unsigned long rate, unsigned long now,
unsigned long best, unsigned long flags)
{
if (flags & CLK_MUX_ROUND_CLOSEST)
return abs(now - rate) < abs(best - rate);
return now <= rate && now > best;
}
static int
clk_mux_determine_rate_flags(struct clk_hw *hw, struct clk_rate_request *req,
unsigned long flags)
{
struct clk_core *core = hw->core, *parent, *best_parent = NULL;
int i, num_parents, ret;
unsigned long best = 0;
struct clk_rate_request parent_req = *req;
/* if NO_REPARENT flag set, pass through to current parent */
if (core->flags & CLK_SET_RATE_NO_REPARENT) {
parent = core->parent;
if (core->flags & CLK_SET_RATE_PARENT) {
ret = __clk_determine_rate(parent ? parent->hw : NULL,
&parent_req);
if (ret)
return ret;
best = parent_req.rate;
} else if (parent) {
best = clk_core_get_rate_nolock(parent);
} else {
best = clk_core_get_rate_nolock(core);
}
goto out;
}
/* find the parent that can provide the fastest rate <= rate */
num_parents = core->num_parents;
for (i = 0; i < num_parents; i++) {
parent = clk_core_get_parent_by_index(core, i);
if (!parent)
continue;
if (core->flags & CLK_SET_RATE_PARENT) {
parent_req = *req;
ret = __clk_determine_rate(parent->hw, &parent_req);
if (ret)
continue;
} else {
parent_req.rate = clk_core_get_rate_nolock(parent);
}
if (mux_is_better_rate(req->rate, parent_req.rate,
best, flags)) {
best_parent = parent;
best = parent_req.rate;
}
}
if (!best_parent)
return -EINVAL;
out:
if (best_parent)
req->best_parent_hw = best_parent->hw;
req->best_parent_rate = best;
req->rate = best;
return 0;
}
struct clk *__clk_lookup(const char *name)
{
struct clk_core *core = clk_core_lookup(name);
return !core ? NULL : core->hw->clk;
}
static void clk_core_get_boundaries(struct clk_core *core,
unsigned long *min_rate,
unsigned long *max_rate)
{
struct clk *clk_user;
*min_rate = core->min_rate;
*max_rate = core->max_rate;
hlist_for_each_entry(clk_user, &core->clks, clks_node)
*min_rate = max(*min_rate, clk_user->min_rate);
hlist_for_each_entry(clk_user, &core->clks, clks_node)
*max_rate = min(*max_rate, clk_user->max_rate);
}
void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate,
unsigned long max_rate)
{
hw->core->min_rate = min_rate;
hw->core->max_rate = max_rate;
}
EXPORT_SYMBOL_GPL(clk_hw_set_rate_range);
/*
* Helper for finding best parent to provide a given frequency. This can be used
* directly as a determine_rate callback (e.g. for a mux), or from a more
* complex clock that may combine a mux with other operations.
*/
int __clk_mux_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
return clk_mux_determine_rate_flags(hw, req, 0);
}
EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
int __clk_mux_determine_rate_closest(struct clk_hw *hw,
struct clk_rate_request *req)
{
return clk_mux_determine_rate_flags(hw, req, CLK_MUX_ROUND_CLOSEST);
}
EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
/*** clk api ***/
static void clk_core_unprepare(struct clk_core *core)
{
lockdep_assert_held(&prepare_lock);
if (!core)
return;
if (WARN_ON(core->prepare_count == 0))
return;
if (WARN_ON(core->prepare_count == 1 && core->flags & CLK_IS_CRITICAL))
return;
if (--core->prepare_count > 0)
return;
WARN_ON(core->enable_count > 0);
trace_clk_unprepare(core);
if (core->ops->unprepare)
core->ops->unprepare(core->hw);
trace_clk_unprepare_complete(core);
clk_core_unprepare(core->parent);
}
static void clk_core_unprepare_lock(struct clk_core *core)
{
clk_prepare_lock();
clk_core_unprepare(core);
clk_prepare_unlock();
}
/**
* clk_unprepare - undo preparation of a clock source
* @clk: the clk being unprepared
*
* clk_unprepare may sleep, which differentiates it from clk_disable. In a
* simple case, clk_unprepare can be used instead of clk_disable to gate a clk
* if the operation may sleep. One example is a clk which is accessed over
* I2c. In the complex case a clk gate operation may require a fast and a slow
* part. It is this reason that clk_unprepare and clk_disable are not mutually
* exclusive. In fact clk_disable must be called before clk_unprepare.
*/
void clk_unprepare(struct clk *clk)
{
if (IS_ERR_OR_NULL(clk))
return;
clk_core_unprepare_lock(clk->core);
}
EXPORT_SYMBOL_GPL(clk_unprepare);
static int clk_core_prepare(struct clk_core *core)
{
int ret = 0;
lockdep_assert_held(&prepare_lock);
if (!core)
return 0;
if (core->prepare_count == 0) {
ret = clk_core_prepare(core->parent);
if (ret)
return ret;
trace_clk_prepare(core);
if (core->ops->prepare)
ret = core->ops->prepare(core->hw);
trace_clk_prepare_complete(core);
if (ret) {
clk_core_unprepare(core->parent);
return ret;
}
}
core->prepare_count++;
return 0;
}
static int clk_core_prepare_lock(struct clk_core *core)
{
int ret;
clk_prepare_lock();
ret = clk_core_prepare(core);
clk_prepare_unlock();
return ret;
}
/**
* clk_prepare - prepare a clock source
* @clk: the clk being prepared
*
* clk_prepare may sleep, which differentiates it from clk_enable. In a simple
* case, clk_prepare can be used instead of clk_enable to ungate a clk if the
* operation may sleep. One example is a clk which is accessed over I2c. In
* the complex case a clk ungate operation may require a fast and a slow part.
* It is this reason that clk_prepare and clk_enable are not mutually
* exclusive. In fact clk_prepare must be called before clk_enable.
* Returns 0 on success, -EERROR otherwise.
*/
int clk_prepare(struct clk *clk)
{
if (!clk)
return 0;
return clk_core_prepare_lock(clk->core);
}
EXPORT_SYMBOL_GPL(clk_prepare);
static void clk_core_disable(struct clk_core *core)
{
lockdep_assert_held(&enable_lock);
if (!core)
return;
if (WARN_ON(core->enable_count == 0))
return;
if (WARN_ON(core->enable_count == 1 && core->flags & CLK_IS_CRITICAL))
return;
if (--core->enable_count > 0)
return;
trace_clk_disable_rcuidle(core);
if (core->ops->disable)
core->ops->disable(core->hw);
trace_clk_disable_complete_rcuidle(core);
clk_core_disable(core->parent);
}
static void clk_core_disable_lock(struct clk_core *core)
{
unsigned long flags;
flags = clk_enable_lock();
clk_core_disable(core);
clk_enable_unlock(flags);
}
/**
* clk_disable - gate a clock
* @clk: the clk being gated
*
* clk_disable must not sleep, which differentiates it from clk_unprepare. In
* a simple case, clk_disable can be used instead of clk_unprepare to gate a
* clk if the operation is fast and will never sleep. One example is a
* SoC-internal clk which is controlled via simple register writes. In the
* complex case a clk gate operation may require a fast and a slow part. It is
* this reason that clk_unprepare and clk_disable are not mutually exclusive.
* In fact clk_disable must be called before clk_unprepare.
*/
void clk_disable(struct clk *clk)
{
if (IS_ERR_OR_NULL(clk))
return;
clk_core_disable_lock(clk->core);
}
EXPORT_SYMBOL_GPL(clk_disable);
static int clk_core_enable(struct clk_core *core)
{
int ret = 0;
lockdep_assert_held(&enable_lock);
if (!core)
return 0;
if (WARN_ON(core->prepare_count == 0))
return -ESHUTDOWN;
if (core->enable_count == 0) {
ret = clk_core_enable(core->parent);
if (ret)
return ret;
trace_clk_enable_rcuidle(core);
if (core->ops->enable)
ret = core->ops->enable(core->hw);
trace_clk_enable_complete_rcuidle(core);
if (ret) {
clk_core_disable(core->parent);
return ret;
}
}
core->enable_count++;
return 0;
}
static int clk_core_enable_lock(struct clk_core *core)
{
unsigned long flags;
int ret;
flags = clk_enable_lock();
ret = clk_core_enable(core);
clk_enable_unlock(flags);
return ret;
}
/**
* clk_enable - ungate a clock
* @clk: the clk being ungated
*
* clk_enable must not sleep, which differentiates it from clk_prepare. In a
* simple case, clk_enable can be used instead of clk_prepare to ungate a clk
* if the operation will never sleep. One example is a SoC-internal clk which
* is controlled via simple register writes. In the complex case a clk ungate
* operation may require a fast and a slow part. It is this reason that
* clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare
* must be called before clk_enable. Returns 0 on success, -EERROR
* otherwise.
*/
int clk_enable(struct clk *clk)
{
if (!clk)
return 0;
return clk_core_enable_lock(clk->core);
}
EXPORT_SYMBOL_GPL(clk_enable);
static int clk_core_prepare_enable(struct clk_core *core)
{
int ret;
ret = clk_core_prepare_lock(core);
if (ret)
return ret;
ret = clk_core_enable_lock(core);
if (ret)
clk_core_unprepare_lock(core);
return ret;
}
static void clk_core_disable_unprepare(struct clk_core *core)
{
clk_core_disable_lock(core);
clk_core_unprepare_lock(core);
}
static void clk_unprepare_unused_subtree(struct clk_core *core)
{
struct clk_core *child;
lockdep_assert_held(&prepare_lock);
hlist_for_each_entry(child, &core->children, child_node)
clk_unprepare_unused_subtree(child);
if (core->prepare_count)
return;
if (core->flags & CLK_IGNORE_UNUSED)
return;
if (clk_core_is_prepared(core)) {
trace_clk_unprepare(core);
if (core->ops->unprepare_unused)
core->ops->unprepare_unused(core->hw);
else if (core->ops->unprepare)
core->ops->unprepare(core->hw);
trace_clk_unprepare_complete(core);
}
}
static void clk_disable_unused_subtree(struct clk_core *core)
{
struct clk_core *child;
unsigned long flags;
lockdep_assert_held(&prepare_lock);
hlist_for_each_entry(child, &core->children, child_node)
clk_disable_unused_subtree(child);
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_prepare_enable(core->parent);
flags = clk_enable_lock();
if (core->enable_count)
goto unlock_out;
if (core->flags & CLK_IGNORE_UNUSED)
goto unlock_out;
/*
* some gate clocks have special needs during the disable-unused
* sequence. call .disable_unused if available, otherwise fall
* back to .disable
*/
if (clk_core_is_enabled(core)) {
trace_clk_disable(core);
if (core->ops->disable_unused)
core->ops->disable_unused(core->hw);
else if (core->ops->disable)
core->ops->disable(core->hw);
trace_clk_disable_complete(core);
}
unlock_out:
clk_enable_unlock(flags);
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_disable_unprepare(core->parent);
}
static bool clk_ignore_unused;
static int __init clk_ignore_unused_setup(char *__unused)
{
clk_ignore_unused = true;
return 1;
}
__setup("clk_ignore_unused", clk_ignore_unused_setup);
static int clk_disable_unused(void)
{
struct clk_core *core;
if (clk_ignore_unused) {
pr_warn("clk: Not disabling unused clocks\n");
return 0;
}
clk_prepare_lock();
hlist_for_each_entry(core, &clk_root_list, child_node)
clk_disable_unused_subtree(core);
hlist_for_each_entry(core, &clk_orphan_list, child_node)
clk_disable_unused_subtree(core);
hlist_for_each_entry(core, &clk_root_list, child_node)
clk_unprepare_unused_subtree(core);
hlist_for_each_entry(core, &clk_orphan_list, child_node)
clk_unprepare_unused_subtree(core);
clk_prepare_unlock();
return 0;
}
late_initcall_sync(clk_disable_unused);
static int clk_core_round_rate_nolock(struct clk_core *core,
struct clk_rate_request *req)
{
struct clk_core *parent;
long rate;
lockdep_assert_held(&prepare_lock);
if (!core)
return 0;
parent = core->parent;
if (parent) {
req->best_parent_hw = parent->hw;
req->best_parent_rate = parent->rate;
} else {
req->best_parent_hw = NULL;
req->best_parent_rate = 0;
}
if (core->ops->determine_rate) {
return core->ops->determine_rate(core->hw, req);
} else if (core->ops->round_rate) {
rate = core->ops->round_rate(core->hw, req->rate,
&req->best_parent_rate);
if (rate < 0)
return rate;
req->rate = rate;
} else if (core->flags & CLK_SET_RATE_PARENT) {
return clk_core_round_rate_nolock(parent, req);
} else {
req->rate = core->rate;
}
return 0;
}
/**
* __clk_determine_rate - get the closest rate actually supported by a clock
* @hw: determine the rate of this clock
* @req: target rate request
*
* Useful for clk_ops such as .set_rate and .determine_rate.
*/
int __clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
{
if (!hw) {
req->rate = 0;
return 0;
}
return clk_core_round_rate_nolock(hw->core, req);
}
EXPORT_SYMBOL_GPL(__clk_determine_rate);
unsigned long clk_hw_round_rate(struct clk_hw *hw, unsigned long rate)
{
int ret;
struct clk_rate_request req;
clk_core_get_boundaries(hw->core, &req.min_rate, &req.max_rate);
req.rate = rate;
ret = clk_core_round_rate_nolock(hw->core, &req);
if (ret)
return 0;
return req.rate;
}
EXPORT_SYMBOL_GPL(clk_hw_round_rate);
/**
* clk_round_rate - round the given rate for a clk
* @clk: the clk for which we are rounding a rate
* @rate: the rate which is to be rounded
*
* Takes in a rate as input and rounds it to a rate that the clk can actually
* use which is then returned. If clk doesn't support round_rate operation
* then the parent rate is returned.
*/
long clk_round_rate(struct clk *clk, unsigned long rate)
{
struct clk_rate_request req;
int ret;
if (!clk)
return 0;
clk_prepare_lock();
clk_core_get_boundaries(clk->core, &req.min_rate, &req.max_rate);
req.rate = rate;
ret = clk_core_round_rate_nolock(clk->core, &req);
clk_prepare_unlock();
if (ret)
return ret;
return req.rate;
}
EXPORT_SYMBOL_GPL(clk_round_rate);
/**
* __clk_notify - call clk notifier chain
* @core: 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_core *core, unsigned long msg,
unsigned long old_rate, unsigned long new_rate)
{
struct clk_notifier *cn;
struct clk_notifier_data cnd;
int ret = NOTIFY_DONE;
cnd.old_rate = old_rate;
cnd.new_rate = new_rate;
list_for_each_entry(cn, &clk_notifier_list, node) {
if (cn->clk->core == core) {
cnd.clk = cn->clk;
ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
&cnd);
if (ret & NOTIFY_STOP_MASK)
return ret;
}
}
return ret;
}
/**
* __clk_recalc_accuracies
* @core: first clk in the subtree
*
* Walks the subtree of clks starting with clk and recalculates accuracies as
* it goes. Note that if a clk does not implement the .recalc_accuracy
* callback then it is assumed that the clock will take on the accuracy of its
* parent.
*/
static void __clk_recalc_accuracies(struct clk_core *core)
{
unsigned long parent_accuracy = 0;
struct clk_core *child;
lockdep_assert_held(&prepare_lock);
if (core->parent)
parent_accuracy = core->parent->accuracy;
if (core->ops->recalc_accuracy)
core->accuracy = core->ops->recalc_accuracy(core->hw,
parent_accuracy);
else
core->accuracy = parent_accuracy;
hlist_for_each_entry(child, &core->children, child_node)
__clk_recalc_accuracies(child);
}
static long clk_core_get_accuracy(struct clk_core *core)
{
unsigned long accuracy;
clk_prepare_lock();
if (core && (core->flags & CLK_GET_ACCURACY_NOCACHE))
__clk_recalc_accuracies(core);
accuracy = __clk_get_accuracy(core);
clk_prepare_unlock();
return accuracy;
}
/**
* clk_get_accuracy - return the accuracy of clk
* @clk: the clk whose accuracy is being returned
*
* Simply returns the cached accuracy of the clk, unless
* CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
* issued.
* If clk is NULL then returns 0.
*/
long clk_get_accuracy(struct clk *clk)
{
if (!clk)
return 0;
return clk_core_get_accuracy(clk->core);
}
EXPORT_SYMBOL_GPL(clk_get_accuracy);
static unsigned long clk_recalc(struct clk_core *core,
unsigned long parent_rate)
{
if (core->ops->recalc_rate)
return core->ops->recalc_rate(core->hw, parent_rate);
return parent_rate;
}
/**
* __clk_recalc_rates
* @core: first clk in the subtree
* @msg: notification type (see include/linux/clk.h)
*
* Walks the subtree of clks starting with clk and recalculates rates as it
* goes. Note that if a clk does not implement the .recalc_rate callback then
* it is assumed that the clock will take on the rate of its parent.
*
* clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
* if necessary.
*/
static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
{
unsigned long old_rate;
unsigned long parent_rate = 0;
struct clk_core *child;
lockdep_assert_held(&prepare_lock);
old_rate = core->rate;
if (core->parent)
parent_rate = core->parent->rate;
core->rate = clk_recalc(core, parent_rate);
/*
* ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
* & ABORT_RATE_CHANGE notifiers
*/
if (core->notifier_count && msg)
__clk_notify(core, msg, old_rate, core->rate);
hlist_for_each_entry(child, &core->children, child_node)
__clk_recalc_rates(child, msg);
}
static unsigned long clk_core_get_rate(struct clk_core *core)
{
unsigned long rate;
clk_prepare_lock();
if (core && (core->flags & CLK_GET_RATE_NOCACHE))
__clk_recalc_rates(core, 0);
rate = clk_core_get_rate_nolock(core);
clk_prepare_unlock();
return rate;
}
/**
* clk_get_rate - return the rate of clk
* @clk: the clk whose rate is being returned
*
* Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
* is set, which means a recalc_rate will be issued.
* If clk is NULL then returns 0.
*/
unsigned long clk_get_rate(struct clk *clk)
{
if (!clk)
return 0;
return clk_core_get_rate(clk->core);
}
EXPORT_SYMBOL_GPL(clk_get_rate);
static int clk_fetch_parent_index(struct clk_core *core,
struct clk_core *parent)
{
int i;
if (!parent)
return -EINVAL;
for (i = 0; i < core->num_parents; i++)
if (clk_core_get_parent_by_index(core, i) == parent)
return i;
return -EINVAL;
}
/*
* Update the orphan status of @core and all its children.
*/
static void clk_core_update_orphan_status(struct clk_core *core, bool is_orphan)
{
struct clk_core *child;
core->orphan = is_orphan;
hlist_for_each_entry(child, &core->children, child_node)
clk_core_update_orphan_status(child, is_orphan);
}
static void clk_reparent(struct clk_core *core, struct clk_core *new_parent)
{
bool was_orphan = core->orphan;
hlist_del(&core->child_node);
if (new_parent) {
bool becomes_orphan = new_parent->orphan;
/* avoid duplicate POST_RATE_CHANGE notifications */
if (new_parent->new_child == core)
new_parent->new_child = NULL;
hlist_add_head(&core->child_node, &new_parent->children);
if (was_orphan != becomes_orphan)
clk_core_update_orphan_status(core, becomes_orphan);
} else {
hlist_add_head(&core->child_node, &clk_orphan_list);
if (!was_orphan)
clk_core_update_orphan_status(core, true);
}
core->parent = new_parent;
}
static struct clk_core *__clk_set_parent_before(struct clk_core *core,
struct clk_core *parent)
{
unsigned long flags;
struct clk_core *old_parent = core->parent;
/*
* 1. enable parents for CLK_OPS_PARENT_ENABLE clock
*
* 2. Migrate prepare state between parents and prevent race with
* clk_enable().
*
* If the clock is not prepared, then a race with
* clk_enable/disable() is impossible since we already have the
* prepare lock (future calls to clk_enable() need to be preceded by
* a clk_prepare()).
*
* If the clock is prepared, migrate the prepared state to the new
* parent and also protect against a race with clk_enable() by
* forcing the clock and the new parent on. This ensures that all
* future calls to clk_enable() are practically NOPs with respect to
* hardware and software states.
*
* See also: Comment for clk_set_parent() below.
*/
/* enable old_parent & parent if CLK_OPS_PARENT_ENABLE is set */
if (core->flags & CLK_OPS_PARENT_ENABLE) {
clk_core_prepare_enable(old_parent);
clk_core_prepare_enable(parent);
}
/* migrate prepare count if > 0 */
if (core->prepare_count) {
clk_core_prepare_enable(parent);
clk_core_enable_lock(core);
}
/* update the clk tree topology */
flags = clk_enable_lock();
clk_reparent(core, parent);
clk_enable_unlock(flags);
return old_parent;
}
static void __clk_set_parent_after(struct clk_core *core,
struct clk_core *parent,
struct clk_core *old_parent)
{
/*
* Finish the migration of prepare state and undo the changes done
* for preventing a race with clk_enable().
*/
if (core->prepare_count) {
clk_core_disable_lock(core);
clk_core_disable_unprepare(old_parent);
}
/* re-balance ref counting if CLK_OPS_PARENT_ENABLE is set */
if (core->flags & CLK_OPS_PARENT_ENABLE) {
clk_core_disable_unprepare(parent);
clk_core_disable_unprepare(old_parent);
}
}
static int __clk_set_parent(struct clk_core *core, struct clk_core *parent,
u8 p_index)
{
unsigned long flags;
int ret = 0;
struct clk_core *old_parent;
old_parent = __clk_set_parent_before(core, parent);
trace_clk_set_parent(core, parent);
/* change clock input source */
if (parent && core->ops->set_parent)
ret = core->ops->set_parent(core->hw, p_index);
trace_clk_set_parent_complete(core, parent);
if (ret) {
flags = clk_enable_lock();
clk_reparent(core, old_parent);
clk_enable_unlock(flags);
__clk_set_parent_after(core, old_parent, parent);
return ret;
}
__clk_set_parent_after(core, parent, old_parent);
return 0;
}
/**
* __clk_speculate_rates
* @core: first clk in the subtree
* @parent_rate: the "future" rate of clk's parent
*
* Walks the subtree of clks starting with clk, speculating rates as it
* goes and firing off PRE_RATE_CHANGE notifications as necessary.
*
* Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
* pre-rate change notifications and returns early if no clks in the
* subtree have subscribed to the notifications. Note that if a clk does not
* implement the .recalc_rate callback then it is assumed that the clock will
* take on the rate of its parent.
*/
static int __clk_speculate_rates(struct clk_core *core,
unsigned long parent_rate)
{
struct clk_core *child;
unsigned long new_rate;
int ret = NOTIFY_DONE;
lockdep_assert_held(&prepare_lock);
new_rate = clk_recalc(core, parent_rate);
/* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
if (core->notifier_count)
ret = __clk_notify(core, PRE_RATE_CHANGE, core->rate, new_rate);
if (ret & NOTIFY_STOP_MASK) {
pr_debug("%s: clk notifier callback for clock %s aborted with error %d\n",
__func__, core->name, ret);
goto out;
}
hlist_for_each_entry(child, &core->children, child_node) {
ret = __clk_speculate_rates(child, new_rate);
if (ret & NOTIFY_STOP_MASK)
break;
}
out:
return ret;
}
static void clk_calc_subtree(struct clk_core *core, unsigned long new_rate,
struct clk_core *new_parent, u8 p_index)
{
struct clk_core *child;
core->new_rate = new_rate;
core->new_parent = new_parent;
core->new_parent_index = p_index;
/* include clk in new parent's PRE_RATE_CHANGE notifications */
core->new_child = NULL;
if (new_parent && new_parent != core->parent)
new_parent->new_child = core;
hlist_for_each_entry(child, &core->children, child_node) {
child->new_rate = clk_recalc(child, new_rate);
clk_calc_subtree(child, child->new_rate, NULL, 0);
}
}
/*
* calculate the new rates returning the topmost clock that has to be
* changed.
*/
static struct clk_core *clk_calc_new_rates(struct clk_core *core,
unsigned long rate)
{
struct clk_core *top = core;
struct clk_core *old_parent, *parent;
unsigned long best_parent_rate = 0;
unsigned long new_rate;
unsigned long min_rate;
unsigned long max_rate;
int p_index = 0;
long ret;
/* sanity */
if (IS_ERR_OR_NULL(core))
return NULL;
/* save parent rate, if it exists */
parent = old_parent = core->parent;
if (parent)
best_parent_rate = parent->rate;
clk_core_get_boundaries(core, &min_rate, &max_rate);
/* find the closest rate and parent clk/rate */
if (core->ops->determine_rate) {
struct clk_rate_request req;
req.rate = rate;
req.min_rate = min_rate;
req.max_rate = max_rate;
if (parent) {
req.best_parent_hw = parent->hw;
req.best_parent_rate = parent->rate;
} else {
req.best_parent_hw = NULL;
req.best_parent_rate = 0;
}
ret = core->ops->determine_rate(core->hw, &req);
if (ret < 0)
return NULL;
best_parent_rate = req.best_parent_rate;
new_rate = req.rate;
parent = req.best_parent_hw ? req.best_parent_hw->core : NULL;
} else if (core->ops->round_rate) {
ret = core->ops->round_rate(core->hw, rate,
&best_parent_rate);
if (ret < 0)
return NULL;
new_rate = ret;
if (new_rate < min_rate || new_rate > max_rate)
return NULL;
} else if (!parent || !(core->flags & CLK_SET_RATE_PARENT)) {
/* pass-through clock without adjustable parent */
core->new_rate = core->rate;
return NULL;
} else {
/* pass-through clock with adjustable parent */
top = clk_calc_new_rates(parent, rate);
new_rate = parent->new_rate;
goto out;
}
/* some clocks must be gated to change parent */
if (parent != old_parent &&
(core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) {
pr_debug("%s: %s not gated but wants to reparent\n",
__func__, core->name);
return NULL;
}
/* try finding the new parent index */
if (parent && core->num_parents > 1) {
p_index = clk_fetch_parent_index(core, parent);
if (p_index < 0) {
pr_debug("%s: clk %s can not be parent of clk %s\n",
__func__, parent->name, core->name);
return NULL;
}
}
if ((core->flags & CLK_SET_RATE_PARENT) && parent &&
best_parent_rate != parent->rate)
top = clk_calc_new_rates(parent, best_parent_rate);
out:
clk_calc_subtree(core, new_rate, parent, p_index);
return top;
}
/*
* Notify about rate changes in a subtree. Always walk down the whole tree
* so that in case of an error we can walk down the whole tree again and
* abort the change.
*/
static struct clk_core *clk_propagate_rate_change(struct clk_core *core,
unsigned long event)
{
struct clk_core *child, *tmp_clk, *fail_clk = NULL;
int ret = NOTIFY_DONE;
if (core->rate == core->new_rate)
return NULL;
if (core->notifier_count) {
ret = __clk_notify(core, event, core->rate, core->new_rate);
if (ret & NOTIFY_STOP_MASK)
fail_clk = core;
}
hlist_for_each_entry(child, &core->children, child_node) {
/* Skip children who will be reparented to another clock */
if (child->new_parent && child->new_parent != core)
continue;
tmp_clk = clk_propagate_rate_change(child, event);
if (tmp_clk)
fail_clk = tmp_clk;
}
/* handle the new child who might not be in core->children yet */
if (core->new_child) {
tmp_clk = clk_propagate_rate_change(core->new_child, event);
if (tmp_clk)
fail_clk = tmp_clk;
}
return fail_clk;
}
/*
* walk down a subtree and set the new rates notifying the rate
* change on the way
*/
static void clk_change_rate(struct clk_core *core)
{
struct clk_core *child;
struct hlist_node *tmp;
unsigned long old_rate;
unsigned long best_parent_rate = 0;
bool skip_set_rate = false;
struct clk_core *old_parent;
struct clk_core *parent = NULL;
old_rate = core->rate;
if (core->new_parent) {
parent = core->new_parent;
best_parent_rate = core->new_parent->rate;
} else if (core->parent) {
parent = core->parent;
best_parent_rate = core->parent->rate;
}
if (core->flags & CLK_SET_RATE_UNGATE) {
unsigned long flags;
clk_core_prepare(core);
flags = clk_enable_lock();
clk_core_enable(core);
clk_enable_unlock(flags);
}
if (core->new_parent && core->new_parent != core->parent) {
old_parent = __clk_set_parent_before(core, core->new_parent);
trace_clk_set_parent(core, core->new_parent);
if (core->ops->set_rate_and_parent) {
skip_set_rate = true;
core->ops->set_rate_and_parent(core->hw, core->new_rate,
best_parent_rate,
core->new_parent_index);
} else if (core->ops->set_parent) {
core->ops->set_parent(core->hw, core->new_parent_index);
}
trace_clk_set_parent_complete(core, core->new_parent);
__clk_set_parent_after(core, core->new_parent, old_parent);
}
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_prepare_enable(parent);
trace_clk_set_rate(core, core->new_rate);
if (!skip_set_rate && core->ops->set_rate)
core->ops->set_rate(core->hw, core->new_rate, best_parent_rate);
trace_clk_set_rate_complete(core, core->new_rate);
core->rate = clk_recalc(core, best_parent_rate);
if (core->flags & CLK_SET_RATE_UNGATE) {
unsigned long flags;
flags = clk_enable_lock();
clk_core_disable(core);
clk_enable_unlock(flags);
clk_core_unprepare(core);
}
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_disable_unprepare(parent);
if (core->notifier_count && old_rate != core->rate)
__clk_notify(core, POST_RATE_CHANGE, old_rate, core->rate);
if (core->flags & CLK_RECALC_NEW_RATES)
(void)clk_calc_new_rates(core, core->new_rate);
/*
* Use safe iteration, as change_rate can actually swap parents
* for certain clock types.
*/
hlist_for_each_entry_safe(child, tmp, &core->children, child_node) {
/* Skip children who will be reparented to another clock */
if (child->new_parent && child->new_parent != core)
continue;
clk_change_rate(child);
}
/* handle the new child who might not be in core->children yet */
if (core->new_child)
clk_change_rate(core->new_child);
}
static int clk_core_set_rate_nolock(struct clk_core *core,
unsigned long req_rate)
{
struct clk_core *top, *fail_clk;
unsigned long rate = req_rate;
if (!core)
return 0;
/* bail early if nothing to do */
if (rate == clk_core_get_rate_nolock(core))
return 0;
if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
return -EBUSY;
/* calculate new rates and get the topmost changed clock */
top = clk_calc_new_rates(core, rate);
if (!top)
return -EINVAL;
/* notify that we are about to change rates */
fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
if (fail_clk) {
pr_debug("%s: failed to set %s rate\n", __func__,
fail_clk->name);
clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
return -EBUSY;
}
/* change the rates */
clk_change_rate(top);
core->req_rate = req_rate;
return 0;
}
/**
* clk_set_rate - specify a new rate for clk
* @clk: the clk whose rate is being changed
* @rate: the new rate for clk
*
* In the simplest case clk_set_rate will only adjust the rate of clk.
*
* Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
* propagate up to clk's parent; whether or not this happens depends on the
* outcome of clk's .round_rate implementation. If *parent_rate is unchanged
* after calling .round_rate then upstream parent propagation is ignored. If
* *parent_rate comes back with a new rate for clk's parent then we propagate
* up to clk's parent and set its rate. Upward propagation will continue
* until either a clk does not support the CLK_SET_RATE_PARENT flag or
* .round_rate stops requesting changes to clk's parent_rate.
*
* Rate changes are accomplished via tree traversal that also recalculates the
* rates for the clocks and fires off POST_RATE_CHANGE notifiers.
*
* Returns 0 on success, -EERROR otherwise.
*/
int clk_set_rate(struct clk *clk, unsigned long rate)
{
int ret;
if (!clk)
return 0;
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
ret = clk_core_set_rate_nolock(clk->core, rate);
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_rate);
/**
* clk_set_rate_range - set a rate range for a clock source
* @clk: clock source
* @min: desired minimum clock rate in Hz, inclusive
* @max: desired maximum clock rate in Hz, inclusive
*
* Returns success (0) or negative errno.
*/
int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
{
int ret = 0;
if (!clk)
return 0;
if (min > max) {
pr_err("%s: clk %s dev %s con %s: invalid range [%lu, %lu]\n",
__func__, clk->core->name, clk->dev_id, clk->con_id,
min, max);
return -EINVAL;
}
clk_prepare_lock();
if (min != clk->min_rate || max != clk->max_rate) {
clk->min_rate = min;
clk->max_rate = max;
ret = clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
}
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_rate_range);
/**
* clk_set_min_rate - set a minimum clock rate for a clock source
* @clk: clock source
* @rate: desired minimum clock rate in Hz, inclusive
*
* Returns success (0) or negative errno.
*/
int clk_set_min_rate(struct clk *clk, unsigned long rate)
{
if (!clk)
return 0;
return clk_set_rate_range(clk, rate, clk->max_rate);
}
EXPORT_SYMBOL_GPL(clk_set_min_rate);
/**
* clk_set_max_rate - set a maximum clock rate for a clock source
* @clk: clock source
* @rate: desired maximum clock rate in Hz, inclusive
*
* Returns success (0) or negative errno.
*/
int clk_set_max_rate(struct clk *clk, unsigned long rate)
{
if (!clk)
return 0;
return clk_set_rate_range(clk, clk->min_rate, rate);
}
EXPORT_SYMBOL_GPL(clk_set_max_rate);
/**
* clk_get_parent - return the parent of a clk
* @clk: the clk whose parent gets returned
*
* Simply returns clk->parent. Returns NULL if clk is NULL.
*/
struct clk *clk_get_parent(struct clk *clk)
{
struct clk *parent;
if (!clk)
return NULL;
clk_prepare_lock();
/* TODO: Create a per-user clk and change callers to call clk_put */
parent = !clk->core->parent ? NULL : clk->core->parent->hw->clk;
clk_prepare_unlock();
return parent;
}
EXPORT_SYMBOL_GPL(clk_get_parent);
static struct clk_core *__clk_init_parent(struct clk_core *core)
{
u8 index = 0;
if (core->num_parents > 1 && core->ops->get_parent)
index = core->ops->get_parent(core->hw);
return clk_core_get_parent_by_index(core, index);
}
static void clk_core_reparent(struct clk_core *core,
struct clk_core *new_parent)
{
clk_reparent(core, new_parent);
__clk_recalc_accuracies(core);
__clk_recalc_rates(core, POST_RATE_CHANGE);
}
void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent)
{
if (!hw)
return;
clk_core_reparent(hw->core, !new_parent ? NULL : new_parent->core);
}
/**
* clk_has_parent - check if a clock is a possible parent for another
* @clk: clock source
* @parent: parent clock source
*
* This function can be used in drivers that need to check that a clock can be
* the parent of another without actually changing the parent.
*
* Returns true if @parent is a possible parent for @clk, false otherwise.
*/
bool clk_has_parent(struct clk *clk, struct clk *parent)
{
struct clk_core *core, *parent_core;
unsigned int i;
/* NULL clocks should be nops, so return success if either is NULL. */
if (!clk || !parent)
return true;
core = clk->core;
parent_core = parent->core;
/* Optimize for the case where the parent is already the parent. */
if (core->parent == parent_core)
return true;
for (i = 0; i < core->num_parents; i++)
if (strcmp(core->parent_names[i], parent_core->name) == 0)
return true;
return false;
}
EXPORT_SYMBOL_GPL(clk_has_parent);
static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent)
{
int ret = 0;
int p_index = 0;
unsigned long p_rate = 0;
if (!core)
return 0;
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
if (core->parent == parent)
goto out;
/* verify ops for for multi-parent clks */
if ((core->num_parents > 1) && (!core->ops->set_parent)) {
ret = -ENOSYS;
goto out;
}
/* check that we are allowed to re-parent if the clock is in use */
if ((core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) {
ret = -EBUSY;
goto out;
}
/* try finding the new parent index */
if (parent) {
p_index = clk_fetch_parent_index(core, parent);
if (p_index < 0) {
pr_debug("%s: clk %s can not be parent of clk %s\n",
__func__, parent->name, core->name);
ret = p_index;
goto out;
}
p_rate = parent->rate;
}
/* propagate PRE_RATE_CHANGE notifications */
ret = __clk_speculate_rates(core, p_rate);
/* abort if a driver objects */
if (ret & NOTIFY_STOP_MASK)
goto out;
/* do the re-parent */
ret = __clk_set_parent(core, parent, p_index);
/* propagate rate an accuracy recalculation accordingly */
if (ret) {
__clk_recalc_rates(core, ABORT_RATE_CHANGE);
} else {
__clk_recalc_rates(core, POST_RATE_CHANGE);
__clk_recalc_accuracies(core);
}
out:
clk_prepare_unlock();
return ret;
}
/**
* clk_set_parent - switch the parent of a mux clk
* @clk: the mux clk whose input we are switching
* @parent: the new input to clk
*
* Re-parent clk to use parent as its new input source. If clk is in
* prepared state, the clk will get enabled for the duration of this call. If
* that's not acceptable for a specific clk (Eg: the consumer can't handle
* that, the reparenting is glitchy in hardware, etc), use the
* CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
*
* After successfully changing clk's parent clk_set_parent will update the
* clk topology, sysfs topology and propagate rate recalculation via
* __clk_recalc_rates.
*
* Returns 0 on success, -EERROR otherwise.
*/
int clk_set_parent(struct clk *clk, struct clk *parent)
{
if (!clk)
return 0;
return clk_core_set_parent(clk->core, parent ? parent->core : NULL);
}
EXPORT_SYMBOL_GPL(clk_set_parent);
/**
* clk_set_phase - adjust the phase shift of a clock signal
* @clk: clock signal source
* @degrees: number of degrees the signal is shifted
*
* Shifts the phase of a clock signal by the specified
* degrees. Returns 0 on success, -EERROR otherwise.
*
* This function makes no distinction about the input or reference
* signal that we adjust the clock signal phase against. For example
* phase locked-loop clock signal generators we may shift phase with
* respect to feedback clock signal input, but for other cases the
* clock phase may be shifted with respect to some other, unspecified
* signal.
*
* Additionally the concept of phase shift does not propagate through
* the clock tree hierarchy, which sets it apart from clock rates and
* clock accuracy. A parent clock phase attribute does not have an
* impact on the phase attribute of a child clock.
*/
int clk_set_phase(struct clk *clk, int degrees)
{
int ret = -EINVAL;
if (!clk)
return 0;
/* sanity check degrees */
degrees %= 360;
if (degrees < 0)
degrees += 360;
clk_prepare_lock();
trace_clk_set_phase(clk->core, degrees);
if (clk->core->ops->set_phase)
ret = clk->core->ops->set_phase(clk->core->hw, degrees);
trace_clk_set_phase_complete(clk->core, degrees);
if (!ret)
clk->core->phase = degrees;
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_phase);
static int clk_core_get_phase(struct clk_core *core)
{
int ret;
clk_prepare_lock();
ret = core->phase;
clk_prepare_unlock();
return ret;
}
/**
* clk_get_phase - return the phase shift of a clock signal
* @clk: clock signal source
*
* Returns the phase shift of a clock node in degrees, otherwise returns
* -EERROR.
*/
int clk_get_phase(struct clk *clk)
{
if (!clk)
return 0;
return clk_core_get_phase(clk->core);
}
EXPORT_SYMBOL_GPL(clk_get_phase);
/**
* clk_is_match - check if two clk's point to the same hardware clock
* @p: clk compared against q
* @q: clk compared against p
*
* Returns true if the two struct clk pointers both point to the same hardware
* clock node. Put differently, returns true if struct clk *p and struct clk *q
* share the same struct clk_core object.
*
* Returns false otherwise. Note that two NULL clks are treated as matching.
*/
bool clk_is_match(const struct clk *p, const struct clk *q)
{
/* trivial case: identical struct clk's or both NULL */
if (p == q)
return true;
/* true if clk->core pointers match. Avoid dereferencing garbage */
if (!IS_ERR_OR_NULL(p) && !IS_ERR_OR_NULL(q))
if (p->core == q->core)
return true;
return false;
}
EXPORT_SYMBOL_GPL(clk_is_match);
/*** debugfs support ***/
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
static struct dentry *rootdir;
static int inited = 0;
static DEFINE_MUTEX(clk_debug_lock);
static HLIST_HEAD(clk_debug_list);
static struct hlist_head *all_lists[] = {
&clk_root_list,
&clk_orphan_list,
NULL,
};
static struct hlist_head *orphan_list[] = {
&clk_orphan_list,
NULL,
};
static void clk_summary_show_one(struct seq_file *s, struct clk_core *c,
int level)
{
if (!c)
return;
seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
level * 3 + 1, "",
30 - level * 3, c->name,
c->enable_count, c->prepare_count, clk_core_get_rate(c),
clk_core_get_accuracy(c), clk_core_get_phase(c));
}
static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c,
int level)
{
struct clk_core *child;
if (!c)
return;
clk_summary_show_one(s, c, level);
hlist_for_each_entry(child, &c->children, child_node)
clk_summary_show_subtree(s, child, level + 1);
}
static int clk_summary_show(struct seq_file *s, void *data)
{
struct clk_core *c;
struct hlist_head **lists = (struct hlist_head **)s->private;
seq_puts(s, " clock enable_cnt prepare_cnt rate accuracy phase\n");
seq_puts(s, "----------------------------------------------------------------------------------------\n");
clk_prepare_lock();
for (; *lists; lists++)
hlist_for_each_entry(c, *lists, child_node)
clk_summary_show_subtree(s, c, 0);
clk_prepare_unlock();
return 0;
}
static int clk_summary_open(struct inode *inode, struct file *file)
{
return single_open(file, clk_summary_show, inode->i_private);
}
static const struct file_operations clk_summary_fops = {
.open = clk_summary_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static void clk_dump_one(struct seq_file *s, struct clk_core *c, int level)
{
if (!c)
return;
/* This should be JSON format, i.e. elements separated with a comma */
seq_printf(s, "\"%s\": { ", c->name);
seq_printf(s, "\"enable_count\": %d,", c->enable_count);
seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
seq_printf(s, "\"rate\": %lu,", clk_core_get_rate(c));
seq_printf(s, "\"accuracy\": %lu,", clk_core_get_accuracy(c));
seq_printf(s, "\"phase\": %d", clk_core_get_phase(c));
}
static void clk_dump_subtree(struct seq_file *s, struct clk_core *c, int level)
{
struct clk_core *child;
if (!c)
return;
clk_dump_one(s, c, level);
hlist_for_each_entry(child, &c->children, child_node) {
seq_putc(s, ',');
clk_dump_subtree(s, child, level + 1);
}
seq_putc(s, '}');
}
static int clk_dump(struct seq_file *s, void *data)
{
struct clk_core *c;
bool first_node = true;
struct hlist_head **lists = (struct hlist_head **)s->private;
seq_putc(s, '{');
clk_prepare_lock();
for (; *lists; lists++) {
hlist_for_each_entry(c, *lists, child_node) {
if (!first_node)
seq_putc(s, ',');
first_node = false;
clk_dump_subtree(s, c, 0);
}
}
clk_prepare_unlock();
seq_puts(s, "}\n");
return 0;
}
static int clk_dump_open(struct inode *inode, struct file *file)
{
return single_open(file, clk_dump, inode->i_private);
}
static const struct file_operations clk_dump_fops = {
.open = clk_dump_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int possible_parents_dump(struct seq_file *s, void *data)
{
struct clk_core *core = s->private;
int i;
for (i = 0; i < core->num_parents - 1; i++)
seq_printf(s, "%s ", core->parent_names[i]);
seq_printf(s, "%s\n", core->parent_names[i]);
return 0;
}
static int possible_parents_open(struct inode *inode, struct file *file)
{
return single_open(file, possible_parents_dump, inode->i_private);
}
static const struct file_operations possible_parents_fops = {
.open = possible_parents_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
{
struct dentry *d;
int ret = -ENOMEM;
if (!core || !pdentry) {
ret = -EINVAL;
goto out;
}
d = debugfs_create_dir(core->name, pdentry);
if (!d)
goto out;
core->dentry = d;
d = debugfs_create_u32("clk_rate", S_IRUGO, core->dentry,
(u32 *)&core->rate);
if (!d)
goto err_out;
d = debugfs_create_u32("clk_accuracy", S_IRUGO, core->dentry,
(u32 *)&core->accuracy);
if (!d)
goto err_out;
d = debugfs_create_u32("clk_phase", S_IRUGO, core->dentry,
(u32 *)&core->phase);
if (!d)
goto err_out;
d = debugfs_create_x32("clk_flags", S_IRUGO, core->dentry,
(u32 *)&core->flags);
if (!d)
goto err_out;
d = debugfs_create_u32("clk_prepare_count", S_IRUGO, core->dentry,
(u32 *)&core->prepare_count);
if (!d)
goto err_out;
d = debugfs_create_u32("clk_enable_count", S_IRUGO, core->dentry,
(u32 *)&core->enable_count);
if (!d)
goto err_out;
d = debugfs_create_u32("clk_notifier_count", S_IRUGO, core->dentry,
(u32 *)&core->notifier_count);
if (!d)
goto err_out;
if (core->num_parents > 1) {
d = debugfs_create_file("clk_possible_parents", S_IRUGO,
core->dentry, core, &possible_parents_fops);
if (!d)
goto err_out;
}
if (core->ops->debug_init) {
ret = core->ops->debug_init(core->hw, core->dentry);
if (ret)
goto err_out;
}
ret = 0;
goto out;
err_out:
debugfs_remove_recursive(core->dentry);
core->dentry = NULL;
out:
return ret;
}
/**
* clk_debug_register - add a clk node to the debugfs clk directory
* @core: the clk being added to the debugfs clk directory
*
* Dynamically adds a clk to the debugfs clk directory if debugfs has been
* initialized. Otherwise it bails out early since the debugfs clk directory
* will be created lazily by clk_debug_init as part of a late_initcall.
*/
static int clk_debug_register(struct clk_core *core)
{
int ret = 0;
mutex_lock(&clk_debug_lock);
hlist_add_head(&core->debug_node, &clk_debug_list);
if (!inited)
goto unlock;
ret = clk_debug_create_one(core, rootdir);
unlock:
mutex_unlock(&clk_debug_lock);
return ret;
}
/**
* clk_debug_unregister - remove a clk node from the debugfs clk directory
* @core: the clk being removed from the debugfs clk directory
*
* Dynamically removes a clk and all its child nodes from the
* debugfs clk directory if clk->dentry points to debugfs created by
* clk_debug_register in __clk_core_init.
*/
static void clk_debug_unregister(struct clk_core *core)
{
mutex_lock(&clk_debug_lock);
hlist_del_init(&core->debug_node);
debugfs_remove_recursive(core->dentry);
core->dentry = NULL;
mutex_unlock(&clk_debug_lock);
}
struct dentry *clk_debugfs_add_file(struct clk_hw *hw, char *name, umode_t mode,
void *data, const struct file_operations *fops)
{
struct dentry *d = NULL;
if (hw->core->dentry)
d = debugfs_create_file(name, mode, hw->core->dentry, data,
fops);
return d;
}
EXPORT_SYMBOL_GPL(clk_debugfs_add_file);
/**
* clk_debug_init - lazily populate the debugfs clk directory
*
* clks are often initialized very early during boot before memory can be
* dynamically allocated and well before debugfs is setup. This function
* populates the debugfs clk directory once at boot-time when we know that
* debugfs is setup. It should only be called once at boot-time, all other clks
* added dynamically will be done so with clk_debug_register.
*/
static int __init clk_debug_init(void)
{
struct clk_core *core;
struct dentry *d;
rootdir = debugfs_create_dir("clk", NULL);
if (!rootdir)
return -ENOMEM;
d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, &all_lists,
&clk_summary_fops);
if (!d)
return -ENOMEM;
d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, &all_lists,
&clk_dump_fops);
if (!d)
return -ENOMEM;
d = debugfs_create_file("clk_orphan_summary", S_IRUGO, rootdir,
&orphan_list, &clk_summary_fops);
if (!d)
return -ENOMEM;
d = debugfs_create_file("clk_orphan_dump", S_IRUGO, rootdir,
&orphan_list, &clk_dump_fops);
if (!d)
return -ENOMEM;
mutex_lock(&clk_debug_lock);
hlist_for_each_entry(core, &clk_debug_list, debug_node)
clk_debug_create_one(core, rootdir);
inited = 1;
mutex_unlock(&clk_debug_lock);
return 0;
}
late_initcall(clk_debug_init);
#else
static inline int clk_debug_register(struct clk_core *core) { return 0; }
static inline void clk_debug_reparent(struct clk_core *core,
struct clk_core *new_parent)
{
}
static inline void clk_debug_unregister(struct clk_core *core)
{
}
#endif
/**
* __clk_core_init - initialize the data structures in a struct clk_core
* @core: clk_core being initialized
*
* Initializes the lists in struct clk_core, queries the hardware for the
* parent and rate and sets them both.
*/
static int __clk_core_init(struct clk_core *core)
{
int i, ret = 0;
struct clk_core *orphan;
struct hlist_node *tmp2;
unsigned long rate;
if (!core)
return -EINVAL;
clk_prepare_lock();
/* check to see if a clock with this name is already registered */
if (clk_core_lookup(core->name)) {
pr_debug("%s: clk %s already initialized\n",
__func__, core->name);
ret = -EEXIST;
goto out;
}
/* check that clk_ops are sane. See Documentation/clk.txt */
if (core->ops->set_rate &&
!((core->ops->round_rate || core->ops->determine_rate) &&
core->ops->recalc_rate)) {
pr_err("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
__func__, core->name);
ret = -EINVAL;
goto out;
}
if (core->ops->set_parent && !core->ops->get_parent) {
pr_err("%s: %s must implement .get_parent & .set_parent\n",
__func__, core->name);
ret = -EINVAL;
goto out;
}
if (core->num_parents > 1 && !core->ops->get_parent) {
pr_err("%s: %s must implement .get_parent as it has multi parents\n",
__func__, core->name);
ret = -EINVAL;
goto out;
}
if (core->ops->set_rate_and_parent &&
!(core->ops->set_parent && core->ops->set_rate)) {
pr_err("%s: %s must implement .set_parent & .set_rate\n",
__func__, core->name);
ret = -EINVAL;
goto out;
}
/* throw a WARN if any entries in parent_names are NULL */
for (i = 0; i < core->num_parents; i++)
WARN(!core->parent_names[i],
"%s: invalid NULL in %s's .parent_names\n",
__func__, core->name);
core->parent = __clk_init_parent(core);
/*
* Populate core->parent if parent has already been clk_core_init'd. If
* parent has not yet been clk_core_init'd then place clk in the orphan
* list. If clk doesn't have any parents then place it in the root
* clk list.
*
* Every time a new clk is clk_init'd then we walk the list of orphan
* clocks and re-parent any that are children of the clock currently
* being clk_init'd.
*/
if (core->parent) {
hlist_add_head(&core->child_node,
&core->parent->children);
core->orphan = core->parent->orphan;
} else if (!core->num_parents) {
hlist_add_head(&core->child_node, &clk_root_list);
core->orphan = false;
} else {
hlist_add_head(&core->child_node, &clk_orphan_list);
core->orphan = true;
}
/*
* Set clk's accuracy. The preferred method is to use
* .recalc_accuracy. For simple clocks and lazy developers the default
* fallback is to use the parent's accuracy. If a clock doesn't have a
* parent (or is orphaned) then accuracy is set to zero (perfect
* clock).
*/
if (core->ops->recalc_accuracy)
core->accuracy = core->ops->recalc_accuracy(core->hw,
__clk_get_accuracy(core->parent));
else if (core->parent)
core->accuracy = core->parent->accuracy;
else
core->accuracy = 0;
/*
* Set clk's phase.
* Since a phase is by definition relative to its parent, just
* query the current clock phase, or just assume it's in phase.
*/
if (core->ops->get_phase)
core->phase = core->ops->get_phase(core->hw);
else
core->phase = 0;
/*
* Set clk's rate. The preferred method is to use .recalc_rate. For
* simple clocks and lazy developers the default fallback is to use the
* parent's rate. If a clock doesn't have a parent (or is orphaned)
* then rate is set to zero.
*/
if (core->ops->recalc_rate)
rate = core->ops->recalc_rate(core->hw,
clk_core_get_rate_nolock(core->parent));
else if (core->parent)
rate = core->parent->rate;
else
rate = 0;
core->rate = core->req_rate = rate;
/*
* walk the list of orphan clocks and reparent any that newly finds a
* parent.
*/
hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
struct clk_core *parent = __clk_init_parent(orphan);
/*
* we could call __clk_set_parent, but that would result in a
* redundant call to the .set_rate op, if it exists
*/
if (parent) {
__clk_set_parent_before(orphan, parent);
__clk_set_parent_after(orphan, parent, NULL);
__clk_recalc_accuracies(orphan);
__clk_recalc_rates(orphan, 0);
}
}
/*
* optional platform-specific magic
*
* The .init callback is not used by any of the basic clock types, but
* exists for weird hardware that must perform initialization magic.
* Please consider other ways of solving initialization problems before
* using this callback, as its use is discouraged.
*/
if (core->ops->init)
core->ops->init(core->hw);
if (core->flags & CLK_IS_CRITICAL) {
unsigned long flags;
clk_core_prepare(core);
flags = clk_enable_lock();
clk_core_enable(core);
clk_enable_unlock(flags);
}
kref_init(&core->ref);
out:
clk_prepare_unlock();
if (!ret)
clk_debug_register(core);
return ret;
}
struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
const char *con_id)
{
struct clk *clk;
/* This is to allow this function to be chained to others */
if (IS_ERR_OR_NULL(hw))
return ERR_CAST(hw);
clk = kzalloc(sizeof(*clk), GFP_KERNEL);
if (!clk)
return ERR_PTR(-ENOMEM);
clk->core = hw->core;
clk->dev_id = dev_id;
clk->con_id = kstrdup_const(con_id, GFP_KERNEL);
clk->max_rate = ULONG_MAX;
clk_prepare_lock();
hlist_add_head(&clk->clks_node, &hw->core->clks);
clk_prepare_unlock();
return clk;
}
void __clk_free_clk(struct clk *clk)
{
clk_prepare_lock();
hlist_del(&clk->clks_node);
clk_prepare_unlock();
kfree_const(clk->con_id);
kfree(clk);
}
/**
* clk_register - allocate a new clock, register it and return an opaque cookie
* @dev: device that is registering this clock
* @hw: link to hardware-specific clock data
*
* clk_register is the primary interface for populating the clock tree with new
* clock nodes. It returns a pointer to the newly allocated struct clk which
* cannot be dereferenced by driver code but may be used in conjunction with the
* rest of the clock API. In the event of an error clk_register will return an
* error code; drivers must test for an error code after calling clk_register.
*/
struct clk *clk_register(struct device *dev, struct clk_hw *hw)
{
int i, ret;
struct clk_core *core;
core = kzalloc(sizeof(*core), GFP_KERNEL);
if (!core) {
ret = -ENOMEM;
goto fail_out;
}
core->name = kstrdup_const(hw->init->name, GFP_KERNEL);
if (!core->name) {
ret = -ENOMEM;
goto fail_name;
}
core->ops = hw->init->ops;
if (dev && dev->driver)
core->owner = dev->driver->owner;
core->hw = hw;
core->flags = hw->init->flags;
core->num_parents = hw->init->num_parents;
core->min_rate = 0;
core->max_rate = ULONG_MAX;
hw->core = core;
/* allocate local copy in case parent_names is __initdata */
core->parent_names = kcalloc(core->num_parents, sizeof(char *),
GFP_KERNEL);
if (!core->parent_names) {
ret = -ENOMEM;
goto fail_parent_names;
}
/* copy each string name in case parent_names is __initdata */
for (i = 0; i < core->num_parents; i++) {
core->parent_names[i] = kstrdup_const(hw->init->parent_names[i],
GFP_KERNEL);
if (!core->parent_names[i]) {
ret = -ENOMEM;
goto fail_parent_names_copy;
}
}
/* avoid unnecessary string look-ups of clk_core's possible parents. */
core->parents = kcalloc(core->num_parents, sizeof(*core->parents),
GFP_KERNEL);
if (!core->parents) {
ret = -ENOMEM;
goto fail_parents;
};
INIT_HLIST_HEAD(&core->clks);
hw->clk = __clk_create_clk(hw, NULL, NULL);
if (IS_ERR(hw->clk)) {
ret = PTR_ERR(hw->clk);
goto fail_parents;
}
ret = __clk_core_init(core);
if (!ret)
return hw->clk;
__clk_free_clk(hw->clk);
hw->clk = NULL;
fail_parents:
kfree(core->parents);
fail_parent_names_copy:
while (--i >= 0)
kfree_const(core->parent_names[i]);
kfree(core->parent_names);
fail_parent_names:
kfree_const(core->name);
fail_name:
kfree(core);
fail_out:
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(clk_register);
/**
* clk_hw_register - register a clk_hw and return an error code
* @dev: device that is registering this clock
* @hw: link to hardware-specific clock data
*
* clk_hw_register is the primary interface for populating the clock tree with
* new clock nodes. It returns an integer equal to zero indicating success or
* less than zero indicating failure. Drivers must test for an error code after
* calling clk_hw_register().
*/
int clk_hw_register(struct device *dev, struct clk_hw *hw)
{
return PTR_ERR_OR_ZERO(clk_register(dev, hw));
}
EXPORT_SYMBOL_GPL(clk_hw_register);
/* Free memory allocated for a clock. */
static void __clk_release(struct kref *ref)
{
struct clk_core *core = container_of(ref, struct clk_core, ref);
int i = core->num_parents;
lockdep_assert_held(&prepare_lock);
kfree(core->parents);
while (--i >= 0)
kfree_const(core->parent_names[i]);
kfree(core->parent_names);
kfree_const(core->name);
kfree(core);
}
/*
* Empty clk_ops for unregistered clocks. These are used temporarily
* after clk_unregister() was called on a clock and until last clock
* consumer calls clk_put() and the struct clk object is freed.
*/
static int clk_nodrv_prepare_enable(struct clk_hw *hw)
{
return -ENXIO;
}
static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
{
WARN_ON_ONCE(1);
}
static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
return -ENXIO;
}
static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
{
return -ENXIO;
}
static const struct clk_ops clk_nodrv_ops = {
.enable = clk_nodrv_prepare_enable,
.disable = clk_nodrv_disable_unprepare,
.prepare = clk_nodrv_prepare_enable,
.unprepare = clk_nodrv_disable_unprepare,
.set_rate = clk_nodrv_set_rate,
.set_parent = clk_nodrv_set_parent,
};
/**
* clk_unregister - unregister a currently registered clock
* @clk: clock to unregister
*/
void clk_unregister(struct clk *clk)
{
unsigned long flags;
if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
return;
clk_debug_unregister(clk->core);
clk_prepare_lock();
if (clk->core->ops == &clk_nodrv_ops) {
pr_err("%s: unregistered clock: %s\n", __func__,
clk->core->name);
goto unlock;
}
/*
* Assign empty clock ops for consumers that might still hold
* a reference to this clock.
*/
flags = clk_enable_lock();
clk->core->ops = &clk_nodrv_ops;
clk_enable_unlock(flags);
if (!hlist_empty(&clk->core->children)) {
struct clk_core *child;
struct hlist_node *t;
/* Reparent all children to the orphan list. */
hlist_for_each_entry_safe(child, t, &clk->core->children,
child_node)
clk_core_set_parent(child, NULL);
}
hlist_del_init(&clk->core->child_node);
if (clk->core->prepare_count)
pr_warn("%s: unregistering prepared clock: %s\n",
__func__, clk->core->name);
kref_put(&clk->core->ref, __clk_release);
unlock:
clk_prepare_unlock();
}
EXPORT_SYMBOL_GPL(clk_unregister);
/**
* clk_hw_unregister - unregister a currently registered clk_hw
* @hw: hardware-specific clock data to unregister
*/
void clk_hw_unregister(struct clk_hw *hw)
{
clk_unregister(hw->clk);
}
EXPORT_SYMBOL_GPL(clk_hw_unregister);
static void devm_clk_release(struct device *dev, void *res)
{
clk_unregister(*(struct clk **)res);
}
static void devm_clk_hw_release(struct device *dev, void *res)
{
clk_hw_unregister(*(struct clk_hw **)res);
}
/**
* devm_clk_register - resource managed clk_register()
* @dev: device that is registering this clock
* @hw: link to hardware-specific clock data
*
* Managed clk_register(). Clocks returned from this function are
* automatically clk_unregister()ed on driver detach. See clk_register() for
* more information.
*/
struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
{
struct clk *clk;
struct clk **clkp;
clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
if (!clkp)
return ERR_PTR(-ENOMEM);
clk = clk_register(dev, hw);
if (!IS_ERR(clk)) {
*clkp = clk;
devres_add(dev, clkp);
} else {
devres_free(clkp);
}
return clk;
}
EXPORT_SYMBOL_GPL(devm_clk_register);
/**
* devm_clk_hw_register - resource managed clk_hw_register()
* @dev: device that is registering this clock
* @hw: link to hardware-specific clock data
*
* Managed clk_hw_register(). Clocks registered by this function are
* automatically clk_hw_unregister()ed on driver detach. See clk_hw_register()
* for more information.
*/
int devm_clk_hw_register(struct device *dev, struct clk_hw *hw)
{
struct clk_hw **hwp;
int ret;
hwp = devres_alloc(devm_clk_hw_release, sizeof(*hwp), GFP_KERNEL);
if (!hwp)
return -ENOMEM;
ret = clk_hw_register(dev, hw);
if (!ret) {
*hwp = hw;
devres_add(dev, hwp);
} else {
devres_free(hwp);
}
return ret;
}
EXPORT_SYMBOL_GPL(devm_clk_hw_register);
static int devm_clk_match(struct device *dev, void *res, void *data)
{
struct clk *c = res;
if (WARN_ON(!c))
return 0;
return c == data;
}
static int devm_clk_hw_match(struct device *dev, void *res, void *data)
{
struct clk_hw *hw = res;
if (WARN_ON(!hw))
return 0;
return hw == data;
}
/**
* devm_clk_unregister - resource managed clk_unregister()
* @clk: clock to unregister
*
* Deallocate a clock allocated with devm_clk_register(). Normally
* this function will not need to be called and the resource management
* code will ensure that the resource is freed.
*/
void devm_clk_unregister(struct device *dev, struct clk *clk)
{
WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
}
EXPORT_SYMBOL_GPL(devm_clk_unregister);
/**
* devm_clk_hw_unregister - resource managed clk_hw_unregister()
* @dev: device that is unregistering the hardware-specific clock data
* @hw: link to hardware-specific clock data
*
* Unregister a clk_hw registered with devm_clk_hw_register(). Normally
* this function will not need to be called and the resource management
* code will ensure that the resource is freed.
*/
void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw)
{
WARN_ON(devres_release(dev, devm_clk_hw_release, devm_clk_hw_match,
hw));
}
EXPORT_SYMBOL_GPL(devm_clk_hw_unregister);
/*
* clkdev helpers
*/
int __clk_get(struct clk *clk)
{
struct clk_core *core = !clk ? NULL : clk->core;
if (core) {
if (!try_module_get(core->owner))
return 0;
kref_get(&core->ref);
}
return 1;
}
void __clk_put(struct clk *clk)
{
struct module *owner;
if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
return;
clk_prepare_lock();
hlist_del(&clk->clks_node);
if (clk->min_rate > clk->core->req_rate ||
clk->max_rate < clk->core->req_rate)
clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
owner = clk->core->owner;
kref_put(&clk->core->ref, __clk_release);
clk_prepare_unlock();
module_put(owner);
kfree(clk);
}
/*** clk rate change notifiers ***/
/**
* clk_notifier_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.
*
* In all notification cases (pre, post and abort rate change) the original
* clock rate is passed to the callback via struct clk_notifier_data.old_rate
* and the new frequency is passed via struct clk_notifier_data.new_rate.
*
* clk_notifier_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 clk_notifier_register(struct clk *clk, struct notifier_block *nb)
{
struct clk_notifier *cn;
int ret = -ENOMEM;
if (!clk || !nb)
return -EINVAL;
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(*cn), 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->core->notifier_count++;
out:
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_notifier_register);
/**
* clk_notifier_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 clk_notifier_register.
*
* Returns -EINVAL if called with null arguments; otherwise, passes
* along the return value of srcu_notifier_chain_unregister().
*/
int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
{
struct clk_notifier *cn = NULL;
int ret = -EINVAL;
if (!clk || !nb)
return -EINVAL;
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->core->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;
}
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_notifier_unregister);
#ifdef CONFIG_OF
/**
* struct of_clk_provider - Clock provider registration structure
* @link: Entry in global list of clock providers
* @node: Pointer to device tree node of clock provider
* @get: Get clock callback. Returns NULL or a struct clk for the
* given clock specifier
* @data: context pointer to be passed into @get callback
*/
struct of_clk_provider {
struct list_head link;
struct device_node *node;
struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
struct clk_hw *(*get_hw)(struct of_phandle_args *clkspec, void *data);
void *data;
};
static const struct of_device_id __clk_of_table_sentinel
__used __section(__clk_of_table_end);
static LIST_HEAD(of_clk_providers);
static DEFINE_MUTEX(of_clk_mutex);
struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
void *data)
{
return data;
}
EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
struct clk_hw *of_clk_hw_simple_get(struct of_phandle_args *clkspec, void *data)
{
return data;
}
EXPORT_SYMBOL_GPL(of_clk_hw_simple_get);
struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
{
struct clk_onecell_data *clk_data = data;
unsigned int idx = clkspec->args[0];
if (idx >= clk_data->clk_num) {
pr_err("%s: invalid clock index %u\n", __func__, idx);
return ERR_PTR(-EINVAL);
}
return clk_data->clks[idx];
}
EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
struct clk_hw *
of_clk_hw_onecell_get(struct of_phandle_args *clkspec, void *data)
{
struct clk_hw_onecell_data *hw_data = data;
unsigned int idx = clkspec->args[0];
if (idx >= hw_data->num) {
pr_err("%s: invalid index %u\n", __func__, idx);
return ERR_PTR(-EINVAL);
}
return hw_data->hws[idx];
}
EXPORT_SYMBOL_GPL(of_clk_hw_onecell_get);
/**
* of_clk_add_provider() - Register a clock provider for a node
* @np: Device node pointer associated with clock provider
* @clk_src_get: callback for decoding clock
* @data: context pointer for @clk_src_get callback.
*/
int of_clk_add_provider(struct device_node *np,
struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
void *data),
void *data)
{
struct of_clk_provider *cp;
int ret;
cp = kzalloc(sizeof(*cp), GFP_KERNEL);
if (!cp)
return -ENOMEM;
cp->node = of_node_get(np);
cp->data = data;
cp->get = clk_src_get;
mutex_lock(&of_clk_mutex);
list_add(&cp->link, &of_clk_providers);
mutex_unlock(&of_clk_mutex);
pr_debug("Added clock from %pOF\n", np);
ret = of_clk_set_defaults(np, true);
if (ret < 0)
of_clk_del_provider(np);
return ret;
}
EXPORT_SYMBOL_GPL(of_clk_add_provider);
/**
* of_clk_add_hw_provider() - Register a clock provider for a node
* @np: Device node pointer associated with clock provider
* @get: callback for decoding clk_hw
* @data: context pointer for @get callback.
*/
int of_clk_add_hw_provider(struct device_node *np,
struct clk_hw *(*get)(struct of_phandle_args *clkspec,
void *data),
void *data)
{
struct of_clk_provider *cp;
int ret;
cp = kzalloc(sizeof(*cp), GFP_KERNEL);
if (!cp)
return -ENOMEM;
cp->node = of_node_get(np);
cp->data = data;
cp->get_hw = get;
mutex_lock(&of_clk_mutex);
list_add(&cp->link, &of_clk_providers);
mutex_unlock(&of_clk_mutex);
pr_debug("Added clk_hw provider from %pOF\n", np);
ret = of_clk_set_defaults(np, true);
if (ret < 0)
of_clk_del_provider(np);
return ret;
}
EXPORT_SYMBOL_GPL(of_clk_add_hw_provider);
/**
* of_clk_del_provider() - Remove a previously registered clock provider
* @np: Device node pointer associated with clock provider
*/
void of_clk_del_provider(struct device_node *np)
{
struct of_clk_provider *cp;
mutex_lock(&of_clk_mutex);
list_for_each_entry(cp, &of_clk_providers, link) {
if (cp->node == np) {
list_del(&cp->link);
of_node_put(cp->node);
kfree(cp);
break;
}
}
mutex_unlock(&of_clk_mutex);
}
EXPORT_SYMBOL_GPL(of_clk_del_provider);
static struct clk_hw *
__of_clk_get_hw_from_provider(struct of_clk_provider *provider,
struct of_phandle_args *clkspec)
{
struct clk *clk;
if (provider->get_hw)
return provider->get_hw(clkspec, provider->data);
clk = provider->get(clkspec, provider->data);
if (IS_ERR(clk))
return ERR_CAST(clk);
return __clk_get_hw(clk);
}
struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
const char *dev_id, const char *con_id)
{
struct of_clk_provider *provider;
struct clk *clk = ERR_PTR(-EPROBE_DEFER);
struct clk_hw *hw;
if (!clkspec)
return ERR_PTR(-EINVAL);
/* Check if we have such a provider in our array */
mutex_lock(&of_clk_mutex);
list_for_each_entry(provider, &of_clk_providers, link) {
if (provider->node == clkspec->np) {
hw = __of_clk_get_hw_from_provider(provider, clkspec);
clk = __clk_create_clk(hw, dev_id, con_id);
}
if (!IS_ERR(clk)) {
if (!__clk_get(clk)) {
__clk_free_clk(clk);
clk = ERR_PTR(-ENOENT);
}
break;
}
}
mutex_unlock(&of_clk_mutex);
return clk;
}
/**
* of_clk_get_from_provider() - Lookup a clock from a clock provider
* @clkspec: pointer to a clock specifier data structure
*
* This function looks up a struct clk from the registered list of clock
* providers, an input is a clock specifier data structure as returned
* from the of_parse_phandle_with_args() function call.
*/
struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
{
return __of_clk_get_from_provider(clkspec, NULL, __func__);
}
EXPORT_SYMBOL_GPL(of_clk_get_from_provider);
/**
* of_clk_get_parent_count() - Count the number of clocks a device node has
* @np: device node to count
*
* Returns: The number of clocks that are possible parents of this node
*/
unsigned int of_clk_get_parent_count(struct device_node *np)
{
int count;
count = of_count_phandle_with_args(np, "clocks", "#clock-cells");
if (count < 0)
return 0;
return count;
}
EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
const char *of_clk_get_parent_name(struct device_node *np, int index)
{
struct of_phandle_args clkspec;
struct property *prop;
const char *clk_name;
const __be32 *vp;
u32 pv;
int rc;
int count;
struct clk *clk;
rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
&clkspec);
if (rc)
return NULL;
index = clkspec.args_count ? clkspec.args[0] : 0;
count = 0;
/* if there is an indices property, use it to transfer the index
* specified into an array offset for the clock-output-names property.
*/
of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
if (index == pv) {
index = count;
break;
}
count++;
}
/* We went off the end of 'clock-indices' without finding it */
if (prop && !vp)
return NULL;
if (of_property_read_string_index(clkspec.np, "clock-output-names",
index,
&clk_name) < 0) {
/*
* Best effort to get the name if the clock has been
* registered with the framework. If the clock isn't
* registered, we return the node name as the name of
* the clock as long as #clock-cells = 0.
*/
clk = of_clk_get_from_provider(&clkspec);
if (IS_ERR(clk)) {
if (clkspec.args_count == 0)
clk_name = clkspec.np->name;
else
clk_name = NULL;
} else {
clk_name = __clk_get_name(clk);
clk_put(clk);
}
}
of_node_put(clkspec.np);
return clk_name;
}
EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
/**
* of_clk_parent_fill() - Fill @parents with names of @np's parents and return
* number of parents
* @np: Device node pointer associated with clock provider
* @parents: pointer to char array that hold the parents' names
* @size: size of the @parents array
*
* Return: number of parents for the clock node.
*/
int of_clk_parent_fill(struct device_node *np, const char **parents,
unsigned int size)
{
unsigned int i = 0;
while (i < size && (parents[i] = of_clk_get_parent_name(np, i)) != NULL)
i++;
return i;
}
EXPORT_SYMBOL_GPL(of_clk_parent_fill);
struct clock_provider {
of_clk_init_cb_t clk_init_cb;
struct device_node *np;
struct list_head node;
};
/*
* This function looks for a parent clock. If there is one, then it
* checks that the provider for this parent clock was initialized, in
* this case the parent clock will be ready.
*/
static int parent_ready(struct device_node *np)
{
int i = 0;
while (true) {
struct clk *clk = of_clk_get(np, i);
/* this parent is ready we can check the next one */
if (!IS_ERR(clk)) {
clk_put(clk);
i++;
continue;
}
/* at least one parent is not ready, we exit now */
if (PTR_ERR(clk) == -EPROBE_DEFER)
return 0;
/*
* Here we make assumption that the device tree is
* written correctly. So an error means that there is
* no more parent. As we didn't exit yet, then the
* previous parent are ready. If there is no clock
* parent, no need to wait for them, then we can
* consider their absence as being ready
*/
return 1;
}
}
/**
* of_clk_detect_critical() - set CLK_IS_CRITICAL flag from Device Tree
* @np: Device node pointer associated with clock provider
* @index: clock index
* @flags: pointer to clk_core->flags
*
* Detects if the clock-critical property exists and, if so, sets the
* corresponding CLK_IS_CRITICAL flag.
*
* Do not use this function. It exists only for legacy Device Tree
* bindings, such as the one-clock-per-node style that are outdated.
* Those bindings typically put all clock data into .dts and the Linux
* driver has no clock data, thus making it impossible to set this flag
* correctly from the driver. Only those drivers may call
* of_clk_detect_critical from their setup functions.
*
* Return: error code or zero on success
*/
int of_clk_detect_critical(struct device_node *np,
int index, unsigned long *flags)
{
struct property *prop;
const __be32 *cur;
uint32_t idx;
if (!np || !flags)
return -EINVAL;
of_property_for_each_u32(np, "clock-critical", prop, cur, idx)
if (index == idx)
*flags |= CLK_IS_CRITICAL;
return 0;
}
/**
* of_clk_init() - Scan and init clock providers from the DT
* @matches: array of compatible values and init functions for providers.
*
* This function scans the device tree for matching clock providers
* and calls their initialization functions. It also does it by trying
* to follow the dependencies.
*/
void __init of_clk_init(const struct of_device_id *matches)
{
const struct of_device_id *match;
struct device_node *np;
struct clock_provider *clk_provider, *next;
bool is_init_done;
bool force = false;
LIST_HEAD(clk_provider_list);
if (!matches)
matches = &__clk_of_table;
/* First prepare the list of the clocks providers */
for_each_matching_node_and_match(np, matches, &match) {
struct clock_provider *parent;
if (!of_device_is_available(np))
continue;
parent = kzalloc(sizeof(*parent), GFP_KERNEL);
if (!parent) {
list_for_each_entry_safe(clk_provider, next,
&clk_provider_list, node) {
list_del(&clk_provider->node);
of_node_put(clk_provider->np);
kfree(clk_provider);
}
of_node_put(np);
return;
}
parent->clk_init_cb = match->data;
parent->np = of_node_get(np);
list_add_tail(&parent->node, &clk_provider_list);
}
while (!list_empty(&clk_provider_list)) {
is_init_done = false;
list_for_each_entry_safe(clk_provider, next,
&clk_provider_list, node) {
if (force || parent_ready(clk_provider->np)) {
/* Don't populate platform devices */
of_node_set_flag(clk_provider->np,
OF_POPULATED);
clk_provider->clk_init_cb(clk_provider->np);
of_clk_set_defaults(clk_provider->np, true);
list_del(&clk_provider->node);
of_node_put(clk_provider->np);
kfree(clk_provider);
is_init_done = true;
}
}
/*
* We didn't manage to initialize any of the
* remaining providers during the last loop, so now we
* initialize all the remaining ones unconditionally
* in case the clock parent was not mandatory
*/
if (!is_init_done)
force = true;
}
}
#endif
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