linux/arch/arm/plat-omap/clock.c
Paul Walmsley e07f469d28 OMAP: clock: bail out early if arch_clock functions not implemented
Bail out before we take the clockfw_lock spinlock if the corresponding
OMAP1 or OMAP2+ clock function is not defined.  The intention is to
reduce and simplify the work that is done inside the spinlock.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
2011-03-07 20:19:39 -07:00

561 lines
11 KiB
C

/*
* linux/arch/arm/plat-omap/clock.c
*
* Copyright (C) 2004 - 2008 Nokia corporation
* Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
*
* Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
*
* 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.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/clk.h>
#include <linux/mutex.h>
#include <linux/cpufreq.h>
#include <linux/debugfs.h>
#include <linux/io.h>
#include <plat/clock.h>
static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);
static DEFINE_SPINLOCK(clockfw_lock);
static struct clk_functions *arch_clock;
/*
* Standard clock functions defined in include/linux/clk.h
*/
int clk_enable(struct clk *clk)
{
unsigned long flags;
int ret;
if (clk == NULL || IS_ERR(clk))
return -EINVAL;
if (!arch_clock || !arch_clock->clk_enable)
return -EINVAL;
spin_lock_irqsave(&clockfw_lock, flags);
ret = arch_clock->clk_enable(clk);
spin_unlock_irqrestore(&clockfw_lock, flags);
return ret;
}
EXPORT_SYMBOL(clk_enable);
void clk_disable(struct clk *clk)
{
unsigned long flags;
if (clk == NULL || IS_ERR(clk))
return;
if (!arch_clock || !arch_clock->clk_disable)
return;
spin_lock_irqsave(&clockfw_lock, flags);
if (clk->usecount == 0) {
pr_err("Trying disable clock %s with 0 usecount\n",
clk->name);
WARN_ON(1);
goto out;
}
arch_clock->clk_disable(clk);
out:
spin_unlock_irqrestore(&clockfw_lock, flags);
}
EXPORT_SYMBOL(clk_disable);
unsigned long clk_get_rate(struct clk *clk)
{
unsigned long flags;
unsigned long ret;
if (clk == NULL || IS_ERR(clk))
return 0;
spin_lock_irqsave(&clockfw_lock, flags);
ret = clk->rate;
spin_unlock_irqrestore(&clockfw_lock, flags);
return ret;
}
EXPORT_SYMBOL(clk_get_rate);
/*
* Optional clock functions defined in include/linux/clk.h
*/
long clk_round_rate(struct clk *clk, unsigned long rate)
{
unsigned long flags;
long ret;
if (clk == NULL || IS_ERR(clk))
return 0;
if (!arch_clock || !arch_clock->clk_round_rate)
return 0;
spin_lock_irqsave(&clockfw_lock, flags);
ret = arch_clock->clk_round_rate(clk, rate);
spin_unlock_irqrestore(&clockfw_lock, flags);
return ret;
}
EXPORT_SYMBOL(clk_round_rate);
int clk_set_rate(struct clk *clk, unsigned long rate)
{
unsigned long flags;
int ret = -EINVAL;
if (clk == NULL || IS_ERR(clk))
return ret;
if (!arch_clock || !arch_clock->clk_set_rate)
return ret;
spin_lock_irqsave(&clockfw_lock, flags);
ret = arch_clock->clk_set_rate(clk, rate);
if (ret == 0)
propagate_rate(clk);
spin_unlock_irqrestore(&clockfw_lock, flags);
return ret;
}
EXPORT_SYMBOL(clk_set_rate);
int clk_set_parent(struct clk *clk, struct clk *parent)
{
unsigned long flags;
int ret = -EINVAL;
if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
return ret;
if (!arch_clock || !arch_clock->clk_set_parent)
return ret;
spin_lock_irqsave(&clockfw_lock, flags);
if (clk->usecount == 0) {
ret = arch_clock->clk_set_parent(clk, parent);
if (ret == 0)
propagate_rate(clk);
} else
ret = -EBUSY;
spin_unlock_irqrestore(&clockfw_lock, flags);
return ret;
}
EXPORT_SYMBOL(clk_set_parent);
struct clk *clk_get_parent(struct clk *clk)
{
return clk->parent;
}
EXPORT_SYMBOL(clk_get_parent);
/*
* OMAP specific clock functions shared between omap1 and omap2
*/
int __initdata mpurate;
/*
* By default we use the rate set by the bootloader.
* You can override this with mpurate= cmdline option.
*/
static int __init omap_clk_setup(char *str)
{
get_option(&str, &mpurate);
if (!mpurate)
return 1;
if (mpurate < 1000)
mpurate *= 1000000;
return 1;
}
__setup("mpurate=", omap_clk_setup);
/* Used for clocks that always have same value as the parent clock */
unsigned long followparent_recalc(struct clk *clk)
{
return clk->parent->rate;
}
/*
* Used for clocks that have the same value as the parent clock,
* divided by some factor
*/
unsigned long omap_fixed_divisor_recalc(struct clk *clk)
{
WARN_ON(!clk->fixed_div);
return clk->parent->rate / clk->fixed_div;
}
void clk_reparent(struct clk *child, struct clk *parent)
{
list_del_init(&child->sibling);
if (parent)
list_add(&child->sibling, &parent->children);
child->parent = parent;
/* now do the debugfs renaming to reattach the child
to the proper parent */
}
/* Propagate rate to children */
void propagate_rate(struct clk *tclk)
{
struct clk *clkp;
list_for_each_entry(clkp, &tclk->children, sibling) {
if (clkp->recalc)
clkp->rate = clkp->recalc(clkp);
propagate_rate(clkp);
}
}
static LIST_HEAD(root_clks);
/**
* recalculate_root_clocks - recalculate and propagate all root clocks
*
* Recalculates all root clocks (clocks with no parent), which if the
* clock's .recalc is set correctly, should also propagate their rates.
* Called at init.
*/
void recalculate_root_clocks(void)
{
struct clk *clkp;
list_for_each_entry(clkp, &root_clks, sibling) {
if (clkp->recalc)
clkp->rate = clkp->recalc(clkp);
propagate_rate(clkp);
}
}
/**
* clk_preinit - initialize any fields in the struct clk before clk init
* @clk: struct clk * to initialize
*
* Initialize any struct clk fields needed before normal clk initialization
* can run. No return value.
*/
void clk_preinit(struct clk *clk)
{
INIT_LIST_HEAD(&clk->children);
}
int clk_register(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return -EINVAL;
/*
* trap out already registered clocks
*/
if (clk->node.next || clk->node.prev)
return 0;
mutex_lock(&clocks_mutex);
if (clk->parent)
list_add(&clk->sibling, &clk->parent->children);
else
list_add(&clk->sibling, &root_clks);
list_add(&clk->node, &clocks);
if (clk->init)
clk->init(clk);
mutex_unlock(&clocks_mutex);
return 0;
}
EXPORT_SYMBOL(clk_register);
void clk_unregister(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return;
mutex_lock(&clocks_mutex);
list_del(&clk->sibling);
list_del(&clk->node);
mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_unregister);
void clk_enable_init_clocks(void)
{
struct clk *clkp;
list_for_each_entry(clkp, &clocks, node) {
if (clkp->flags & ENABLE_ON_INIT)
clk_enable(clkp);
}
}
/**
* omap_clk_get_by_name - locate OMAP struct clk by its name
* @name: name of the struct clk to locate
*
* Locate an OMAP struct clk by its name. Assumes that struct clk
* names are unique. Returns NULL if not found or a pointer to the
* struct clk if found.
*/
struct clk *omap_clk_get_by_name(const char *name)
{
struct clk *c;
struct clk *ret = NULL;
mutex_lock(&clocks_mutex);
list_for_each_entry(c, &clocks, node) {
if (!strcmp(c->name, name)) {
ret = c;
break;
}
}
mutex_unlock(&clocks_mutex);
return ret;
}
int omap_clk_enable_autoidle_all(void)
{
struct clk *c;
unsigned long flags;
spin_lock_irqsave(&clockfw_lock, flags);
list_for_each_entry(c, &clocks, node)
if (c->ops->allow_idle)
c->ops->allow_idle(c);
spin_unlock_irqrestore(&clockfw_lock, flags);
return 0;
}
int omap_clk_disable_autoidle_all(void)
{
struct clk *c;
unsigned long flags;
spin_lock_irqsave(&clockfw_lock, flags);
list_for_each_entry(c, &clocks, node)
if (c->ops->deny_idle)
c->ops->deny_idle(c);
spin_unlock_irqrestore(&clockfw_lock, flags);
return 0;
}
/*
* Low level helpers
*/
static int clkll_enable_null(struct clk *clk)
{
return 0;
}
static void clkll_disable_null(struct clk *clk)
{
}
const struct clkops clkops_null = {
.enable = clkll_enable_null,
.disable = clkll_disable_null,
};
/*
* Dummy clock
*
* Used for clock aliases that are needed on some OMAPs, but not others
*/
struct clk dummy_ck = {
.name = "dummy",
.ops = &clkops_null,
};
#ifdef CONFIG_CPU_FREQ
void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
{
unsigned long flags;
if (!arch_clock || !arch_clock->clk_init_cpufreq_table)
return;
spin_lock_irqsave(&clockfw_lock, flags);
arch_clock->clk_init_cpufreq_table(table);
spin_unlock_irqrestore(&clockfw_lock, flags);
}
void clk_exit_cpufreq_table(struct cpufreq_frequency_table **table)
{
unsigned long flags;
if (!arch_clock || !arch_clock->clk_exit_cpufreq_table)
return;
spin_lock_irqsave(&clockfw_lock, flags);
arch_clock->clk_exit_cpufreq_table(table);
spin_unlock_irqrestore(&clockfw_lock, flags);
}
#endif
/*
*
*/
#ifdef CONFIG_OMAP_RESET_CLOCKS
/*
* Disable any unused clocks left on by the bootloader
*/
static int __init clk_disable_unused(void)
{
struct clk *ck;
unsigned long flags;
if (!arch_clock || !arch_clock->clk_disable_unused)
return 0;
pr_info("clock: disabling unused clocks to save power\n");
list_for_each_entry(ck, &clocks, node) {
if (ck->ops == &clkops_null)
continue;
if (ck->usecount > 0 || !ck->enable_reg)
continue;
spin_lock_irqsave(&clockfw_lock, flags);
arch_clock->clk_disable_unused(ck);
spin_unlock_irqrestore(&clockfw_lock, flags);
}
return 0;
}
late_initcall(clk_disable_unused);
late_initcall(omap_clk_enable_autoidle_all);
#endif
int __init clk_init(struct clk_functions * custom_clocks)
{
if (!custom_clocks) {
pr_err("No custom clock functions registered\n");
BUG();
}
arch_clock = custom_clocks;
return 0;
}
#if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
/*
* debugfs support to trace clock tree hierarchy and attributes
*/
static struct dentry *clk_debugfs_root;
static int clk_debugfs_register_one(struct clk *c)
{
int err;
struct dentry *d, *child, *child_tmp;
struct clk *pa = c->parent;
char s[255];
char *p = s;
p += sprintf(p, "%s", c->name);
d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
if (!d)
return -ENOMEM;
c->dent = d;
d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
if (!d) {
err = -ENOMEM;
goto err_out;
}
d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
if (!d) {
err = -ENOMEM;
goto err_out;
}
d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
if (!d) {
err = -ENOMEM;
goto err_out;
}
return 0;
err_out:
d = c->dent;
list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
debugfs_remove(child);
debugfs_remove(c->dent);
return err;
}
static int clk_debugfs_register(struct clk *c)
{
int err;
struct clk *pa = c->parent;
if (pa && !pa->dent) {
err = clk_debugfs_register(pa);
if (err)
return err;
}
if (!c->dent) {
err = clk_debugfs_register_one(c);
if (err)
return err;
}
return 0;
}
static int __init clk_debugfs_init(void)
{
struct clk *c;
struct dentry *d;
int err;
d = debugfs_create_dir("clock", NULL);
if (!d)
return -ENOMEM;
clk_debugfs_root = d;
list_for_each_entry(c, &clocks, node) {
err = clk_debugfs_register(c);
if (err)
goto err_out;
}
return 0;
err_out:
debugfs_remove_recursive(clk_debugfs_root);
return err;
}
late_initcall(clk_debugfs_init);
#endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */