original development tree for Linux kernel GTP module; now long in mainline.
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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-private.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>
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);
/*** 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)
{
unsigned long flags;
if (!spin_trylock_irqsave(&enable_lock, flags)) {
if (enable_owner == current) {
enable_refcnt++;
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)
{
WARN_ON_ONCE(enable_owner != current);
WARN_ON_ONCE(enable_refcnt == 0);
if (--enable_refcnt)
return;
enable_owner = NULL;
spin_unlock_irqrestore(&enable_lock, flags);
}
/*** debugfs support ***/
#ifdef CONFIG_COMMON_CLK_DEBUG
#include <linux/debugfs.h>
static struct dentry *rootdir;
static struct dentry *orphandir;
static int inited = 0;
static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
{
if (!c)
return;
seq_printf(s, "%*s%-*s %-11d %-12d %-10lu",
level * 3 + 1, "",
30 - level * 3, c->name,
c->enable_count, c->prepare_count, clk_get_rate(c));
seq_printf(s, "\n");
}
static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
int level)
{
struct clk *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 *c;
seq_printf(s, " clock enable_cnt prepare_cnt rate\n");
seq_printf(s, "---------------------------------------------------------------------\n");
clk_prepare_lock();
hlist_for_each_entry(c, &clk_root_list, child_node)
clk_summary_show_subtree(s, c, 0);
hlist_for_each_entry(c, &clk_orphan_list, 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 *c, int level)
{
if (!c)
return;
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_get_rate(c));
}
static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
{
struct clk *child;
if (!c)
return;
clk_dump_one(s, c, level);
hlist_for_each_entry(child, &c->children, child_node) {
seq_printf(s, ",");
clk_dump_subtree(s, child, level + 1);
}
seq_printf(s, "}");
}
static int clk_dump(struct seq_file *s, void *data)
{
struct clk *c;
bool first_node = true;
seq_printf(s, "{");
clk_prepare_lock();
hlist_for_each_entry(c, &clk_root_list, child_node) {
if (!first_node)
seq_printf(s, ",");
first_node = false;
clk_dump_subtree(s, c, 0);
}
hlist_for_each_entry(c, &clk_orphan_list, child_node) {
seq_printf(s, ",");
clk_dump_subtree(s, c, 0);
}
clk_prepare_unlock();
seq_printf(s, "}");
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,
};
/* caller must hold prepare_lock */
static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
{
struct dentry *d;
int ret = -ENOMEM;
if (!clk || !pdentry) {
ret = -EINVAL;
goto out;
}
d = debugfs_create_dir(clk->name, pdentry);
if (!d)
goto out;
clk->dentry = d;
d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
(u32 *)&clk->rate);
if (!d)
goto err_out;
d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
(u32 *)&clk->flags);
if (!d)
goto err_out;
d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
(u32 *)&clk->prepare_count);
if (!d)
goto err_out;
d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
(u32 *)&clk->enable_count);
if (!d)
goto err_out;
d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
(u32 *)&clk->notifier_count);
if (!d)
goto err_out;
ret = 0;
goto out;
err_out:
debugfs_remove(clk->dentry);
out:
return ret;
}
/* caller must hold prepare_lock */
static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
{
struct clk *child;
int ret = -EINVAL;;
if (!clk || !pdentry)
goto out;
ret = clk_debug_create_one(clk, pdentry);
if (ret)
goto out;
hlist_for_each_entry(child, &clk->children, child_node)
clk_debug_create_subtree(child, clk->dentry);
ret = 0;
out:
return ret;
}
/**
* clk_debug_register - add a clk node to the debugfs clk tree
* @clk: the clk being added to the debugfs clk tree
*
* Dynamically adds a clk to the debugfs clk tree if debugfs has been
* initialized. Otherwise it bails out early since the debugfs clk tree
* will be created lazily by clk_debug_init as part of a late_initcall.
*
* Caller must hold prepare_lock. Only clk_init calls this function (so
* far) so this is taken care.
*/
static int clk_debug_register(struct clk *clk)
{
struct clk *parent;
struct dentry *pdentry;
int ret = 0;
if (!inited)
goto out;
parent = clk->parent;
/*
* Check to see if a clk is a root clk. Also check that it is
* safe to add this clk to debugfs
*/
if (!parent)
if (clk->flags & CLK_IS_ROOT)
pdentry = rootdir;
else
pdentry = orphandir;
else
if (parent->dentry)
pdentry = parent->dentry;
else
goto out;
ret = clk_debug_create_subtree(clk, pdentry);
out:
return ret;
}
/**
* clk_debug_reparent - reparent clk node in the debugfs clk tree
* @clk: the clk being reparented
* @new_parent: the new clk parent, may be NULL
*
* Rename clk entry in the debugfs clk tree if debugfs has been
* initialized. Otherwise it bails out early since the debugfs clk tree
* will be created lazily by clk_debug_init as part of a late_initcall.
*
* Caller must hold prepare_lock.
*/
static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
{
struct dentry *d;
struct dentry *new_parent_d;
if (!inited)
return;
if (new_parent)
new_parent_d = new_parent->dentry;
else
new_parent_d = orphandir;
d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
new_parent_d, clk->name);
if (d)
clk->dentry = d;
else
pr_debug("%s: failed to rename debugfs entry for %s\n",
__func__, clk->name);
}
/**
* clk_debug_init - lazily create the debugfs clk tree visualization
*
* clks are often initialized very early during boot before memory can
* be dynamically allocated and well before debugfs is setup.
* clk_debug_init walks the clk tree hierarchy while holding
* prepare_lock and creates the topology as part of a late_initcall,
* thus insuring that clks initialized very early will still be
* represented in the debugfs clk tree. This function should only be
* called once at boot-time, and all other clks added dynamically will
* be done so with clk_debug_register.
*/
static int __init clk_debug_init(void)
{
struct clk *clk;
struct dentry *d;
rootdir = debugfs_create_dir("clk", NULL);
if (!rootdir)
return -ENOMEM;
d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
&clk_summary_fops);
if (!d)
return -ENOMEM;
d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
&clk_dump_fops);
if (!d)
return -ENOMEM;
orphandir = debugfs_create_dir("orphans", rootdir);
if (!orphandir)
return -ENOMEM;
clk_prepare_lock();
hlist_for_each_entry(clk, &clk_root_list, child_node)
clk_debug_create_subtree(clk, rootdir);
hlist_for_each_entry(clk, &clk_orphan_list, child_node)
clk_debug_create_subtree(clk, orphandir);
inited = 1;
clk_prepare_unlock();
return 0;
}
late_initcall(clk_debug_init);
#else
static inline int clk_debug_register(struct clk *clk) { return 0; }
static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
{
}
#endif
/* caller must hold prepare_lock */
static void clk_unprepare_unused_subtree(struct clk *clk)
{
struct clk *child;
if (!clk)
return;
hlist_for_each_entry(child, &clk->children, child_node)
clk_unprepare_unused_subtree(child);
if (clk->prepare_count)
return;
if (clk->flags & CLK_IGNORE_UNUSED)
return;
if (__clk_is_prepared(clk)) {
if (clk->ops->unprepare_unused)
clk->ops->unprepare_unused(clk->hw);
else if (clk->ops->unprepare)
clk->ops->unprepare(clk->hw);
}
}
/* caller must hold prepare_lock */
static void clk_disable_unused_subtree(struct clk *clk)
{
struct clk *child;
unsigned long flags;
if (!clk)
goto out;
hlist_for_each_entry(child, &clk->children, child_node)
clk_disable_unused_subtree(child);
flags = clk_enable_lock();
if (clk->enable_count)
goto unlock_out;
if (clk->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_is_enabled(clk)) {
if (clk->ops->disable_unused)
clk->ops->disable_unused(clk->hw);
else if (clk->ops->disable)
clk->ops->disable(clk->hw);
}
unlock_out:
clk_enable_unlock(flags);
out:
return;
}
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 *clk;
if (clk_ignore_unused) {
pr_warn("clk: Not disabling unused clocks\n");
return 0;
}
clk_prepare_lock();
hlist_for_each_entry(clk, &clk_root_list, child_node)
clk_disable_unused_subtree(clk);
hlist_for_each_entry(clk, &clk_orphan_list, child_node)
clk_disable_unused_subtree(clk);
hlist_for_each_entry(clk, &clk_root_list, child_node)
clk_unprepare_unused_subtree(clk);
hlist_for_each_entry(clk, &clk_orphan_list, child_node)
clk_unprepare_unused_subtree(clk);
clk_prepare_unlock();
return 0;
}
late_initcall_sync(clk_disable_unused);
/*** helper functions ***/
const char *__clk_get_name(struct clk *clk)
{
return !clk ? NULL : clk->name;
}
EXPORT_SYMBOL_GPL(__clk_get_name);
struct clk_hw *__clk_get_hw(struct clk *clk)
{
return !clk ? NULL : clk->hw;
}
u8 __clk_get_num_parents(struct clk *clk)
{
return !clk ? 0 : clk->num_parents;
}
struct clk *__clk_get_parent(struct clk *clk)
{
return !clk ? NULL : clk->parent;
}
struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
{
if (!clk || index >= clk->num_parents)
return NULL;
else if (!clk->parents)
return __clk_lookup(clk->parent_names[index]);
else if (!clk->parents[index])
return clk->parents[index] =
__clk_lookup(clk->parent_names[index]);
else
return clk->parents[index];
}
unsigned int __clk_get_enable_count(struct clk *clk)
{
return !clk ? 0 : clk->enable_count;
}
unsigned int __clk_get_prepare_count(struct clk *clk)
{
return !clk ? 0 : clk->prepare_count;
}
unsigned long __clk_get_rate(struct clk *clk)
{
unsigned long ret;
if (!clk) {
ret = 0;
goto out;
}
ret = clk->rate;
if (clk->flags & CLK_IS_ROOT)
goto out;
if (!clk->parent)
ret = 0;
out:
return ret;
}
unsigned long __clk_get_flags(struct clk *clk)
{
return !clk ? 0 : clk->flags;
}
EXPORT_SYMBOL_GPL(__clk_get_flags);
bool __clk_is_prepared(struct clk *clk)
{
int ret;
if (!clk)
return false;
/*
* .is_prepared is optional for clocks that can prepare
* fall back to software usage counter if it is missing
*/
if (!clk->ops->is_prepared) {
ret = clk->prepare_count ? 1 : 0;
goto out;
}
ret = clk->ops->is_prepared(clk->hw);
out:
return !!ret;
}
bool __clk_is_enabled(struct clk *clk)
{
int ret;
if (!clk)
return false;
/*
* .is_enabled is only mandatory for clocks that gate
* fall back to software usage counter if .is_enabled is missing
*/
if (!clk->ops->is_enabled) {
ret = clk->enable_count ? 1 : 0;
goto out;
}
ret = clk->ops->is_enabled(clk->hw);
out:
return !!ret;
}
static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
{
struct clk *child;
struct clk *ret;
if (!strcmp(clk->name, name))
return clk;
hlist_for_each_entry(child, &clk->children, child_node) {
ret = __clk_lookup_subtree(name, child);
if (ret)
return ret;
}
return NULL;
}
struct clk *__clk_lookup(const char *name)
{
struct clk *root_clk;
struct clk *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;
}
/*
* 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.
*/
long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *best_parent_rate,
struct clk **best_parent_p)
{
struct clk *clk = hw->clk, *parent, *best_parent = NULL;
int i, num_parents;
unsigned long parent_rate, best = 0;
/* if NO_REPARENT flag set, pass through to current parent */
if (clk->flags & CLK_SET_RATE_NO_REPARENT) {
parent = clk->parent;
if (clk->flags & CLK_SET_RATE_PARENT)
best = __clk_round_rate(parent, rate);
else if (parent)
best = __clk_get_rate(parent);
else
best = __clk_get_rate(clk);
goto out;
}
/* find the parent that can provide the fastest rate <= rate */
num_parents = clk->num_parents;
for (i = 0; i < num_parents; i++) {
parent = clk_get_parent_by_index(clk, i);
if (!parent)
continue;
if (clk->flags & CLK_SET_RATE_PARENT)
parent_rate = __clk_round_rate(parent, rate);
else
parent_rate = __clk_get_rate(parent);
if (parent_rate <= rate && parent_rate > best) {
best_parent = parent;
best = parent_rate;
}
}
out:
if (best_parent)
*best_parent_p = best_parent;
*best_parent_rate = best;
return best;
}
/*** clk api ***/
void __clk_unprepare(struct clk *clk)
{
if (!clk)
return;
if (WARN_ON(clk->prepare_count == 0))
return;
if (--clk->prepare_count > 0)
return;
WARN_ON(clk->enable_count > 0);
if (clk->ops->unprepare)
clk->ops->unprepare(clk->hw);
__clk_unprepare(clk->parent);
}
/**
* 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)
{
clk_prepare_lock();
__clk_unprepare(clk);
clk_prepare_unlock();
}
EXPORT_SYMBOL_GPL(clk_unprepare);
int __clk_prepare(struct clk *clk)
{
int ret = 0;
if (!clk)
return 0;
if (clk->prepare_count == 0) {
ret = __clk_prepare(clk->parent);
if (ret)
return ret;
if (clk->ops->prepare) {
ret = clk->ops->prepare(clk->hw);
if (ret) {
__clk_unprepare(clk->parent);
return ret;
}
}
}
clk->prepare_count++;
return 0;
}
/**
* 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)
{
int ret;
clk_prepare_lock();
ret = __clk_prepare(clk);
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_prepare);
static void __clk_disable(struct clk *clk)
{
if (!clk)
return;
if (WARN_ON(IS_ERR(clk)))
return;
if (WARN_ON(clk->enable_count == 0))
return;
if (--clk->enable_count > 0)
return;
if (clk->ops->disable)
clk->ops->disable(clk->hw);
__clk_disable(clk->parent);
}
/**
* 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)
{
unsigned long flags;
flags = clk_enable_lock();
__clk_disable(clk);
clk_enable_unlock(flags);
}
EXPORT_SYMBOL_GPL(clk_disable);
static int __clk_enable(struct clk *clk)
{
int ret = 0;
if (!clk)
return 0;
if (WARN_ON(clk->prepare_count == 0))
return -ESHUTDOWN;
if (clk->enable_count == 0) {
ret = __clk_enable(clk->parent);
if (ret)
return ret;
if (clk->ops->enable) {
ret = clk->ops->enable(clk->hw);
if (ret) {
__clk_disable(clk->parent);
return ret;
}
}
}
clk->enable_count++;
return 0;
}
/**
* 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)
{
unsigned long flags;
int ret;
flags = clk_enable_lock();
ret = __clk_enable(clk);
clk_enable_unlock(flags);
return ret;
}
EXPORT_SYMBOL_GPL(clk_enable);
/**
* __clk_round_rate - round the given rate for a clk
* @clk: round the rate of this clock
* @rate: the rate which is to be rounded
*
* Caller must hold prepare_lock. Useful for clk_ops such as .set_rate
*/
unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
{
unsigned long parent_rate = 0;
struct clk *parent;
if (!clk)
return 0;
parent = clk->parent;
if (parent)
parent_rate = parent->rate;
if (clk->ops->determine_rate)
return clk->ops->determine_rate(clk->hw, rate, &parent_rate,
&parent);
else if (clk->ops->round_rate)
return clk->ops->round_rate(clk->hw, rate, &parent_rate);
else if (clk->flags & CLK_SET_RATE_PARENT)
return __clk_round_rate(clk->parent, rate);
else
return clk->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)
{
unsigned long ret;
clk_prepare_lock();
ret = __clk_round_rate(clk, rate);
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_round_rate);
/**
* __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 clk_notifier *cn;
struct 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_recalc_rates
* @clk: 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.
*
* Caller must hold prepare_lock.
*/
static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
{
unsigned long old_rate;
unsigned long parent_rate = 0;
struct clk *child;
old_rate = clk->rate;
if (clk->parent)
parent_rate = clk->parent->rate;
if (clk->ops->recalc_rate)
clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
else
clk->rate = parent_rate;
/*
* ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
* & ABORT_RATE_CHANGE notifiers
*/
if (clk->notifier_count && msg)
__clk_notify(clk, msg, old_rate, clk->rate);
hlist_for_each_entry(child, &clk->children, child_node)
__clk_recalc_rates(child, msg);
}
/**
* 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)
{
unsigned long rate;
clk_prepare_lock();
if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
__clk_recalc_rates(clk, 0);
rate = __clk_get_rate(clk);
clk_prepare_unlock();
return rate;
}
EXPORT_SYMBOL_GPL(clk_get_rate);
static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
{
u8 i;
if (!clk->parents)
clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
GFP_KERNEL);
/*
* find index of new parent clock using cached parent ptrs,
* or if not yet cached, use string name comparison and cache
* them now to avoid future calls to __clk_lookup.
*/
for (i = 0; i < clk->num_parents; i++) {
if (clk->parents && clk->parents[i] == parent)
break;
else if (!strcmp(clk->parent_names[i], parent->name)) {
if (clk->parents)
clk->parents[i] = __clk_lookup(parent->name);
break;
}
}
return i;
}
static void clk_reparent(struct clk *clk, struct clk *new_parent)
{
hlist_del(&clk->child_node);
if (new_parent) {
/* avoid duplicate POST_RATE_CHANGE notifications */
if (new_parent->new_child == clk)
new_parent->new_child = NULL;
hlist_add_head(&clk->child_node, &new_parent->children);
} else {
hlist_add_head(&clk->child_node, &clk_orphan_list);
}
clk->parent = new_parent;
}
static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
{
unsigned long flags;
int ret = 0;
struct clk *old_parent = clk->parent;
/*
* 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.
*/
if (clk->prepare_count) {
__clk_prepare(parent);
clk_enable(parent);
clk_enable(clk);
}
/* update the clk tree topology */
flags = clk_enable_lock();
clk_reparent(clk, parent);
clk_enable_unlock(flags);
/* change clock input source */
if (parent && clk->ops->set_parent)
ret = clk->ops->set_parent(clk->hw, p_index);
if (ret) {
flags = clk_enable_lock();
clk_reparent(clk, old_parent);
clk_enable_unlock(flags);
if (clk->prepare_count) {
clk_disable(clk);
clk_disable(parent);
__clk_unprepare(parent);
}
return ret;
}
/*
* Finish the migration of prepare state and undo the changes done
* for preventing a race with clk_enable().
*/
if (clk->prepare_count) {
clk_disable(clk);
clk_disable(old_parent);
__clk_unprepare(old_parent);
}
/* update debugfs with new clk tree topology */
clk_debug_reparent(clk, parent);
return 0;
}
/**
* __clk_speculate_rates
* @clk: 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.
*
* Caller must hold prepare_lock.
*/
static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
{
struct clk *child;
unsigned long new_rate;
int ret = NOTIFY_DONE;
if (clk->ops->recalc_rate)
new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
else
new_rate = parent_rate;
/* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
if (clk->notifier_count)
ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
if (ret & NOTIFY_STOP_MASK)
goto out;
hlist_for_each_entry(child, &clk->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 *clk, unsigned long new_rate,
struct clk *new_parent, u8 p_index)
{
struct clk *child;
clk->new_rate = new_rate;
clk->new_parent = new_parent;
clk->new_parent_index = p_index;
/* include clk in new parent's PRE_RATE_CHANGE notifications */
clk->new_child = NULL;
if (new_parent && new_parent != clk->parent)
new_parent->new_child = clk;
hlist_for_each_entry(child, &clk->children, child_node) {
if (child->ops->recalc_rate)
child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
else
child->new_rate = 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 *clk_calc_new_rates(struct clk *clk, unsigned long rate)
{
struct clk *top = clk;
struct clk *old_parent, *parent;
unsigned long best_parent_rate = 0;
unsigned long new_rate;
u8 p_index = 0;
/* sanity */
if (IS_ERR_OR_NULL(clk))
return NULL;
/* save parent rate, if it exists */
parent = old_parent = clk->parent;
if (parent)
best_parent_rate = parent->rate;
/* find the closest rate and parent clk/rate */
if (clk->ops->determine_rate) {
new_rate = clk->ops->determine_rate(clk->hw, rate,
&best_parent_rate,
&parent);
} else if (clk->ops->round_rate) {
new_rate = clk->ops->round_rate(clk->hw, rate,
&best_parent_rate);
} else if (!parent || !(clk->flags & CLK_SET_RATE_PARENT)) {
/* pass-through clock without adjustable parent */
clk->new_rate = clk->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 &&
(clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
pr_debug("%s: %s not gated but wants to reparent\n",
__func__, clk->name);
return NULL;
}
/* try finding the new parent index */
if (parent) {
p_index = clk_fetch_parent_index(clk, parent);
if (p_index == clk->num_parents) {
pr_debug("%s: clk %s can not be parent of clk %s\n",
__func__, parent->name, clk->name);
return NULL;
}
}
if ((clk->flags & CLK_SET_RATE_PARENT) && parent &&
best_parent_rate != parent->rate)
top = clk_calc_new_rates(parent, best_parent_rate);
out:
clk_calc_subtree(clk, 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 *clk_propagate_rate_change(struct clk *clk, unsigned long event)
{
struct clk *child, *tmp_clk, *fail_clk = NULL;
int ret = NOTIFY_DONE;
if (clk->rate == clk->new_rate)
return NULL;
if (clk->notifier_count) {
ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
if (ret & NOTIFY_STOP_MASK)
fail_clk = clk;
}
hlist_for_each_entry(child, &clk->children, child_node) {
/* Skip children who will be reparented to another clock */
if (child->new_parent && child->new_parent != clk)
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 clk->children yet */
if (clk->new_child) {
tmp_clk = clk_propagate_rate_change(clk->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 *clk)
{
struct clk *child;
unsigned long old_rate;
unsigned long best_parent_rate = 0;
old_rate = clk->rate;
/* set parent */
if (clk->new_parent && clk->new_parent != clk->parent)
__clk_set_parent(clk, clk->new_parent, clk->new_parent_index);
if (clk->parent)
best_parent_rate = clk->parent->rate;
if (clk->ops->set_rate)
clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
if (clk->ops->recalc_rate)
clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
else
clk->rate = best_parent_rate;
if (clk->notifier_count && old_rate != clk->rate)
__clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
hlist_for_each_entry(child, &clk->children, child_node) {
/* Skip children who will be reparented to another clock */
if (child->new_parent && child->new_parent != clk)
continue;
clk_change_rate(child);
}
/* handle the new child who might not be in clk->children yet */
if (clk->new_child)
clk_change_rate(clk->new_child);
}
/**
* 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)
{
struct clk *top, *fail_clk;
int ret = 0;
if (!clk)
return 0;
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
/* bail early if nothing to do */
if (rate == clk_get_rate(clk))
goto out;
if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
ret = -EBUSY;
goto out;
}
/* calculate new rates and get the topmost changed clock */
top = clk_calc_new_rates(clk, rate);
if (!top) {
ret = -EINVAL;
goto out;
}
/* notify that we are about to change rates */
fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
if (fail_clk) {
pr_warn("%s: failed to set %s rate\n", __func__,
fail_clk->name);
clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
ret = -EBUSY;
goto out;
}
/* change the rates */
clk_change_rate(top);
out:
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_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;
clk_prepare_lock();
parent = __clk_get_parent(clk);
clk_prepare_unlock();
return parent;
}
EXPORT_SYMBOL_GPL(clk_get_parent);
/*
* .get_parent is mandatory for clocks with multiple possible parents. It is
* optional for single-parent clocks. Always call .get_parent if it is
* available and WARN if it is missing for multi-parent clocks.
*
* For single-parent clocks without .get_parent, first check to see if the
* .parents array exists, and if so use it to avoid an expensive tree
* traversal. If .parents does not exist then walk the tree with __clk_lookup.
*/
static struct clk *__clk_init_parent(struct clk *clk)
{
struct clk *ret = NULL;
u8 index;
/* handle the trivial cases */
if (!clk->num_parents)
goto out;
if (clk->num_parents == 1) {
if (IS_ERR_OR_NULL(clk->parent))
ret = clk->parent = __clk_lookup(clk->parent_names[0]);
ret = clk->parent;
goto out;
}
if (!clk->ops->get_parent) {
WARN(!clk->ops->get_parent,
"%s: multi-parent clocks must implement .get_parent\n",
__func__);
goto out;
};
/*
* Do our best to cache parent clocks in clk->parents. This prevents
* unnecessary and expensive calls to __clk_lookup. We don't set
* clk->parent here; that is done by the calling function
*/
index = clk->ops->get_parent(clk->hw);
if (!clk->parents)
clk->parents =
kzalloc((sizeof(struct clk*) * clk->num_parents),
GFP_KERNEL);
ret = clk_get_parent_by_index(clk, index);
out:
return ret;
}
void __clk_reparent(struct clk *clk, struct clk *new_parent)
{
clk_reparent(clk, new_parent);
clk_debug_reparent(clk, new_parent);
__clk_recalc_rates(clk, POST_RATE_CHANGE);
}
/**
* 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)
{
int ret = 0;
u8 p_index = 0;
unsigned long p_rate = 0;
if (!clk)
return 0;
if (!clk->ops)
return -EINVAL;
/* verify ops for for multi-parent clks */
if ((clk->num_parents > 1) && (!clk->ops->set_parent))
return -ENOSYS;
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
if (clk->parent == parent)
goto out;
/* check that we are allowed to re-parent if the clock is in use */
if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
ret = -EBUSY;
goto out;
}
/* try finding the new parent index */
if (parent) {
p_index = clk_fetch_parent_index(clk, parent);
p_rate = parent->rate;
if (p_index == clk->num_parents) {
pr_debug("%s: clk %s can not be parent of clk %s\n",
__func__, parent->name, clk->name);
ret = -EINVAL;
goto out;
}
}
/* propagate PRE_RATE_CHANGE notifications */
ret = __clk_speculate_rates(clk, p_rate);
/* abort if a driver objects */
if (ret & NOTIFY_STOP_MASK)
goto out;
/* do the re-parent */
ret = __clk_set_parent(clk, parent, p_index);
/* propagate rate recalculation accordingly */
if (ret)
__clk_recalc_rates(clk, ABORT_RATE_CHANGE);
else
__clk_recalc_rates(clk, POST_RATE_CHANGE);
out:
clk_prepare_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_parent);
/**
* __clk_init - initialize the data structures in a struct clk
* @dev: device initializing this clk, placeholder for now
* @clk: clk being initialized
*
* Initializes the lists in struct clk, queries the hardware for the
* parent and rate and sets them both.
*/
int __clk_init(struct device *dev, struct clk *clk)
{
int i, ret = 0;
struct clk *orphan;
struct hlist_node *tmp2;
if (!clk)
return -EINVAL;
clk_prepare_lock();
/* check to see if a clock with this name is already registered */
if (__clk_lookup(clk->name)) {
pr_debug("%s: clk %s already initialized\n",
__func__, clk->name);
ret = -EEXIST;
goto out;
}
/* check that clk_ops are sane. See Documentation/clk.txt */
if (clk->ops->set_rate &&
!((clk->ops->round_rate || clk->ops->determine_rate) &&
clk->ops->recalc_rate)) {
pr_warning("%s: %s must implement .round_rate or .determine_rate in addition to .recalc_rate\n",
__func__, clk->name);
ret = -EINVAL;
goto out;
}
if (clk->ops->set_parent && !clk->ops->get_parent) {
pr_warning("%s: %s must implement .get_parent & .set_parent\n",
__func__, clk->name);
ret = -EINVAL;
goto out;
}
/* throw a WARN if any entries in parent_names are NULL */
for (i = 0; i < clk->num_parents; i++)
WARN(!clk->parent_names[i],
"%s: invalid NULL in %s's .parent_names\n",
__func__, clk->name);
/*
* Allocate an array of struct clk *'s to avoid unnecessary string
* look-ups of clk's possible parents. This can fail for clocks passed
* in to clk_init during early boot; thus any access to clk->parents[]
* must always check for a NULL pointer and try to populate it if
* necessary.
*
* If clk->parents is not NULL we skip this entire block. This allows
* for clock drivers to statically initialize clk->parents.
*/
if (clk->num_parents > 1 && !clk->parents) {
clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
GFP_KERNEL);
/*
* __clk_lookup returns NULL for parents that have not been
* clk_init'd; thus any access to clk->parents[] must check
* for a NULL pointer. We can always perform lazy lookups for
* missing parents later on.
*/
if (clk->parents)
for (i = 0; i < clk->num_parents; i++)
clk->parents[i] =
__clk_lookup(clk->parent_names[i]);
}
clk->parent = __clk_init_parent(clk);
/*
* Populate clk->parent if parent has already been __clk_init'd. If
* parent has not yet been __clk_init'd then place clk in the orphan
* list. If clk has set the CLK_IS_ROOT flag 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 (clk->parent)
hlist_add_head(&clk->child_node,
&clk->parent->children);
else if (clk->flags & CLK_IS_ROOT)
hlist_add_head(&clk->child_node, &clk_root_list);
else
hlist_add_head(&clk->child_node, &clk_orphan_list);
/*
* 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 (clk->ops->recalc_rate)
clk->rate = clk->ops->recalc_rate(clk->hw,
__clk_get_rate(clk->parent));
else if (clk->parent)
clk->rate = clk->parent->rate;
else
clk->rate = 0;
/*
* walk the list of orphan clocks and reparent any that are children of
* this clock
*/
hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
if (orphan->num_parents && orphan->ops->get_parent) {
i = orphan->ops->get_parent(orphan->hw);
if (!strcmp(clk->name, orphan->parent_names[i]))
__clk_reparent(orphan, clk);
continue;
}
for (i = 0; i < orphan->num_parents; i++)
if (!strcmp(clk->name, orphan->parent_names[i])) {
__clk_reparent(orphan, clk);
break;
}
}
/*
* 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 (clk->ops->init)
clk->ops->init(clk->hw);
clk_debug_register(clk);
out:
clk_prepare_unlock();
return ret;
}
/**
* __clk_register - register a clock and return a cookie.
*
* Same as clk_register, except that the .clk field inside hw shall point to a
* preallocated (generally statically allocated) struct clk. None of the fields
* of the struct clk need to be initialized.
*
* The data pointed to by .init and .clk field shall NOT be marked as init
* data.
*
* __clk_register is only exposed via clk-private.h and is intended for use with
* very large numbers of clocks that need to be statically initialized. It is
* a layering violation to include clk-private.h from any code which implements
* a clock's .ops; as such any statically initialized clock data MUST be in a
* separate C file from the logic that implements its operations. Returns 0
* on success, otherwise an error code.
*/
struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
{
int ret;
struct clk *clk;
clk = hw->clk;
clk->name = hw->init->name;
clk->ops = hw->init->ops;
clk->hw = hw;
clk->flags = hw->init->flags;
clk->parent_names = hw->init->parent_names;
clk->num_parents = hw->init->num_parents;
ret = __clk_init(dev, clk);
if (ret)
return ERR_PTR(ret);
return clk;
}
EXPORT_SYMBOL_GPL(__clk_register);
static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
{
int i, ret;
clk->name = kstrdup(hw->init->name, GFP_KERNEL);
if (!clk->name) {
pr_err("%s: could not allocate clk->name\n", __func__);
ret = -ENOMEM;
goto fail_name;
}
clk->ops = hw->init->ops;
clk->hw = hw;
clk->flags = hw->init->flags;
clk->num_parents = hw->init->num_parents;
hw->clk = clk;
/* allocate local copy in case parent_names is __initdata */
clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents),
GFP_KERNEL);
if (!clk->parent_names) {
pr_err("%s: could not allocate clk->parent_names\n", __func__);
ret = -ENOMEM;
goto fail_parent_names;
}
/* copy each string name in case parent_names is __initdata */
for (i = 0; i < clk->num_parents; i++) {
clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
GFP_KERNEL);
if (!clk->parent_names[i]) {
pr_err("%s: could not copy parent_names\n", __func__);
ret = -ENOMEM;
goto fail_parent_names_copy;
}
}
ret = __clk_init(dev, clk);
if (!ret)
return 0;
fail_parent_names_copy:
while (--i >= 0)
kfree(clk->parent_names[i]);
kfree(clk->parent_names);
fail_parent_names:
kfree(clk->name);
fail_name:
return ret;
}
/**
* 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 conjuction 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 ret;
struct clk *clk;
clk = kzalloc(sizeof(*clk), GFP_KERNEL);
if (!clk) {
pr_err("%s: could not allocate clk\n", __func__);
ret = -ENOMEM;
goto fail_out;
}
ret = _clk_register(dev, hw, clk);
if (!ret)
return clk;
kfree(clk);
fail_out:
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(clk_register);
/**
* clk_unregister - unregister a currently registered clock
* @clk: clock to unregister
*
* Currently unimplemented.
*/
void clk_unregister(struct clk *clk) {}
EXPORT_SYMBOL_GPL(clk_unregister);
static void devm_clk_release(struct device *dev, void *res)
{
clk_unregister(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;
int ret;
clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
if (!clk)
return ERR_PTR(-ENOMEM);
ret = _clk_register(dev, hw, clk);
if (!ret) {
devres_add(dev, clk);
} else {
devres_free(clk);
clk = ERR_PTR(ret);
}
return clk;
}
EXPORT_SYMBOL_GPL(devm_clk_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;
}
/**
* 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);
/*** 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.
*
* Pre-change notifier callbacks will be passed the current, pre-change
* rate of the clk via struct clk_notifier_data.old_rate. The new,
* post-change rate of the clk is passed via struct
* clk_notifier_data.new_rate.
*
* Post-change notifiers will pass the now-current, post-change rate of
* the clk in both struct clk_notifier_data.old_rate and struct
* 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
* clk_notifier_data.new_rate and the failed post-change rate is passed
* in via struct clk_notifier_data.old_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(struct 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:
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->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);
void *data;
};
extern struct of_device_id __clk_of_table[];
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_lock);
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 *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 %d\n", __func__, idx);
return ERR_PTR(-EINVAL);
}
return clk_data->clks[idx];
}
EXPORT_SYMBOL_GPL(of_clk_src_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;
cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
if (!cp)
return -ENOMEM;
cp->node = of_node_get(np);
cp->data = data;
cp->get = clk_src_get;
mutex_lock(&of_clk_lock);
list_add(&cp->link, &of_clk_providers);
mutex_unlock(&of_clk_lock);
pr_debug("Added clock from %s\n", np->full_name);
return 0;
}
EXPORT_SYMBOL_GPL(of_clk_add_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_lock);
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_lock);
}
EXPORT_SYMBOL_GPL(of_clk_del_provider);
struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
{
struct of_clk_provider *provider;
struct clk *clk = ERR_PTR(-ENOENT);
/* Check if we have such a provider in our array */
mutex_lock(&of_clk_lock);
list_for_each_entry(provider, &of_clk_providers, link) {
if (provider->node == clkspec->np)
clk = provider->get(clkspec, provider->data);
if (!IS_ERR(clk))
break;
}
mutex_unlock(&of_clk_lock);
return clk;
}
const char *of_clk_get_parent_name(struct device_node *np, int index)
{
struct of_phandle_args clkspec;
const char *clk_name;
int rc;
if (index < 0)
return NULL;
rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
&clkspec);
if (rc)
return NULL;
if (of_property_read_string_index(clkspec.np, "clock-output-names",
clkspec.args_count ? clkspec.args[0] : 0,
&clk_name) < 0)
clk_name = clkspec.np->name;
of_node_put(clkspec.np);
return clk_name;
}
EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
/**
* 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
*/
void __init of_clk_init(const struct of_device_id *matches)
{
const struct of_device_id *match;
struct device_node *np;
if (!matches)
matches = __clk_of_table;
for_each_matching_node_and_match(np, matches, &match) {
of_clk_init_cb_t clk_init_cb = match->data;
clk_init_cb(np);
}
}
#endif