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linux-next/drivers/clk/clk.c
Olof Johansson 1e435256d6 clk: add clk_ignore_unused option to keep boot clocks on
This is primarily useful when there's a driver that doesn't claim clocks
properly, but the bootloader leaves them on. It's not expected to be used
in normal cases, but for bringup and debug it's very useful to have the
option to not gate unclaimed clocks that are still on.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: fixed up trivial merge issue]
2013-04-27 23:03:43 -07:00

2131 lines
50 KiB
C

/*
* 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, c->rate);
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", c->rate);
}
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);
}
}
EXPORT_SYMBOL_GPL(__clk_get_flags);
/* 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(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;
}
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;
}
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;
}
/*** 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 unprepare
*
* 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
*
* 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;
if (!clk)
return 0;
if (!clk->ops->round_rate) {
if (clk->flags & CLK_SET_RATE_PARENT)
return __clk_round_rate(clk->parent, rate);
else
return clk->rate;
}
if (clk->parent)
parent_rate = clk->parent->rate;
return clk->ops->round_rate(clk->hw, rate, &parent_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 it's 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);
/**
* __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 it's 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 *child;
clk->new_rate = new_rate;
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);
}
}
/*
* 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;
unsigned long best_parent_rate = 0;
unsigned long new_rate;
/* sanity */
if (IS_ERR_OR_NULL(clk))
return NULL;
/* save parent rate, if it exists */
if (clk->parent)
best_parent_rate = clk->parent->rate;
/* never propagate up to the parent */
if (!(clk->flags & CLK_SET_RATE_PARENT)) {
if (!clk->ops->round_rate) {
clk->new_rate = clk->rate;
return NULL;
}
new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
goto out;
}
/* need clk->parent from here on out */
if (!clk->parent) {
pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
return NULL;
}
if (!clk->ops->round_rate) {
top = clk_calc_new_rates(clk->parent, rate);
new_rate = clk->parent->new_rate;
goto out;
}
new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
if (best_parent_rate != clk->parent->rate) {
top = clk_calc_new_rates(clk->parent, best_parent_rate);
goto out;
}
out:
clk_calc_subtree(clk, new_rate);
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, *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) {
clk = clk_propagate_rate_change(child, event);
if (clk)
fail_clk = 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;
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)
clk_change_rate(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 it's 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;
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
/* bail early if nothing to do */
if (rate == clk->rate)
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);
if (!clk->parents)
ret = __clk_lookup(clk->parent_names[index]);
else if (!clk->parents[index])
ret = clk->parents[index] =
__clk_lookup(clk->parent_names[index]);
else
ret = clk->parents[index];
out:
return ret;
}
static void clk_reparent(struct clk *clk, struct clk *new_parent)
{
hlist_del(&clk->child_node);
if (new_parent)
hlist_add_head(&clk->child_node, &new_parent->children);
else
hlist_add_head(&clk->child_node, &clk_orphan_list);
clk->parent = new_parent;
}
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);
}
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 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;
bool migrated_enable = false;
/* migrate prepare */
if (clk->prepare_count)
__clk_prepare(parent);
flags = clk_enable_lock();
/* migrate enable */
if (clk->enable_count) {
__clk_enable(parent);
migrated_enable = true;
}
/* update the clk tree topology */
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) {
/*
* The error handling is tricky due to that we need to release
* the spinlock while issuing the .set_parent callback. This
* means the new parent might have been enabled/disabled in
* between, which must be considered when doing rollback.
*/
flags = clk_enable_lock();
clk_reparent(clk, old_parent);
if (migrated_enable && clk->enable_count) {
__clk_disable(parent);
} else if (migrated_enable && (clk->enable_count == 0)) {
__clk_disable(old_parent);
} else if (!migrated_enable && clk->enable_count) {
__clk_disable(parent);
__clk_enable(old_parent);
}
clk_enable_unlock(flags);
if (clk->prepare_count)
__clk_unprepare(parent);
return ret;
}
/* clean up enable for old parent if migration was done */
if (migrated_enable) {
flags = clk_enable_lock();
__clk_disable(old_parent);
clk_enable_unlock(flags);
}
/* clean up prepare for old parent if migration was done */
if (clk->prepare_count)
__clk_unprepare(old_parent);
/* update debugfs with new clk tree topology */
clk_debug_reparent(clk, parent);
return 0;
}
/**
* 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 it's new input source. If clk has the
* CLK_SET_PARENT_GATE flag set then clk must be gated for this
* operation to succeed. 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 || !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 */
if (clk->notifier_count)
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->recalc_rate)) {
pr_warning("%s: %s must implement .round_rate & .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->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 it's 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 it's 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);
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)
{
struct device_node *np;
if (!matches)
matches = __clk_of_table;
for_each_matching_node(np, matches) {
const struct of_device_id *match = of_match_node(matches, np);
of_clk_init_cb_t clk_init_cb = match->data;
clk_init_cb(np);
}
}
#endif