original_kernel/arch/sh/kernel/cpu/clock.c

278 lines
5.9 KiB
C

/*
* arch/sh/kernel/cpu/clock.c - SuperH clock framework
*
* Copyright (C) 2005, 2006 Paul Mundt
*
* This clock framework is derived from the OMAP version by:
*
* Copyright (C) 2004 Nokia Corporation
* Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/kref.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <asm/clock.h>
#include <asm/timer.h>
static LIST_HEAD(clock_list);
static DEFINE_SPINLOCK(clock_lock);
static DEFINE_MUTEX(clock_list_sem);
/*
* Each subtype is expected to define the init routines for these clocks,
* as each subtype (or processor family) will have these clocks at the
* very least. These are all provided through the CPG, which even some of
* the more quirky parts (such as ST40, SH4-202, etc.) still have.
*
* The processor-specific code is expected to register any additional
* clock sources that are of interest.
*/
static struct clk master_clk = {
.name = "master_clk",
.flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
.rate = CONFIG_SH_PCLK_FREQ,
};
static struct clk module_clk = {
.name = "module_clk",
.parent = &master_clk,
.flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
};
static struct clk bus_clk = {
.name = "bus_clk",
.parent = &master_clk,
.flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
};
static struct clk cpu_clk = {
.name = "cpu_clk",
.parent = &master_clk,
.flags = CLK_ALWAYS_ENABLED,
};
/*
* The ordering of these clocks matters, do not change it.
*/
static struct clk *onchip_clocks[] = {
&master_clk,
&module_clk,
&bus_clk,
&cpu_clk,
};
static void propagate_rate(struct clk *clk)
{
struct clk *clkp;
list_for_each_entry(clkp, &clock_list, node) {
if (likely(clkp->parent != clk))
continue;
if (likely(clkp->ops && clkp->ops->recalc))
clkp->ops->recalc(clkp);
}
}
int __clk_enable(struct clk *clk)
{
/*
* See if this is the first time we're enabling the clock, some
* clocks that are always enabled still require "special"
* initialization. This is especially true if the clock mode
* changes and the clock needs to hunt for the proper set of
* divisors to use before it can effectively recalc.
*/
if (unlikely(atomic_read(&clk->kref.refcount) == 1))
if (clk->ops && clk->ops->init)
clk->ops->init(clk);
if (clk->flags & CLK_ALWAYS_ENABLED)
return 0;
if (likely(clk->ops && clk->ops->enable))
clk->ops->enable(clk);
kref_get(&clk->kref);
return 0;
}
int clk_enable(struct clk *clk)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&clock_lock, flags);
ret = __clk_enable(clk);
spin_unlock_irqrestore(&clock_lock, flags);
return ret;
}
static void clk_kref_release(struct kref *kref)
{
/* Nothing to do */
}
void __clk_disable(struct clk *clk)
{
if (clk->flags & CLK_ALWAYS_ENABLED)
return;
kref_put(&clk->kref, clk_kref_release);
}
void clk_disable(struct clk *clk)
{
unsigned long flags;
spin_lock_irqsave(&clock_lock, flags);
__clk_disable(clk);
spin_unlock_irqrestore(&clock_lock, flags);
}
int clk_register(struct clk *clk)
{
mutex_lock(&clock_list_sem);
list_add(&clk->node, &clock_list);
kref_init(&clk->kref);
mutex_unlock(&clock_list_sem);
return 0;
}
void clk_unregister(struct clk *clk)
{
mutex_lock(&clock_list_sem);
list_del(&clk->node);
mutex_unlock(&clock_list_sem);
}
inline unsigned long clk_get_rate(struct clk *clk)
{
return clk->rate;
}
int clk_set_rate(struct clk *clk, unsigned long rate)
{
int ret = -EOPNOTSUPP;
if (likely(clk->ops && clk->ops->set_rate)) {
unsigned long flags;
spin_lock_irqsave(&clock_lock, flags);
ret = clk->ops->set_rate(clk, rate);
spin_unlock_irqrestore(&clock_lock, flags);
}
if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
propagate_rate(clk);
return ret;
}
void clk_recalc_rate(struct clk *clk)
{
if (likely(clk->ops && clk->ops->recalc)) {
unsigned long flags;
spin_lock_irqsave(&clock_lock, flags);
clk->ops->recalc(clk);
spin_unlock_irqrestore(&clock_lock, flags);
}
if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
propagate_rate(clk);
}
struct clk *clk_get(const char *id)
{
struct clk *p, *clk = ERR_PTR(-ENOENT);
mutex_lock(&clock_list_sem);
list_for_each_entry(p, &clock_list, node) {
if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
clk = p;
break;
}
}
mutex_unlock(&clock_list_sem);
return clk;
}
void clk_put(struct clk *clk)
{
if (clk && !IS_ERR(clk))
module_put(clk->owner);
}
void __init __attribute__ ((weak))
arch_init_clk_ops(struct clk_ops **ops, int type)
{
}
int __init clk_init(void)
{
int i, ret = 0;
BUG_ON(!master_clk.rate);
for (i = 0; i < ARRAY_SIZE(onchip_clocks); i++) {
struct clk *clk = onchip_clocks[i];
arch_init_clk_ops(&clk->ops, i);
ret |= clk_register(clk);
clk_enable(clk);
}
/* Kick the child clocks.. */
propagate_rate(&master_clk);
propagate_rate(&bus_clk);
return ret;
}
int show_clocks(struct seq_file *m)
{
struct clk *clk;
list_for_each_entry_reverse(clk, &clock_list, node) {
unsigned long rate = clk_get_rate(clk);
/*
* Don't bother listing dummy clocks with no ancestry
* that only support enable and disable ops.
*/
if (unlikely(!rate && !clk->parent))
continue;
seq_printf(m, "%-12s\t: %ld.%02ldMHz\n", clk->name,
rate / 1000000, (rate % 1000000) / 10000);
}
return 0;
}
EXPORT_SYMBOL_GPL(clk_register);
EXPORT_SYMBOL_GPL(clk_unregister);
EXPORT_SYMBOL_GPL(clk_get);
EXPORT_SYMBOL_GPL(clk_put);
EXPORT_SYMBOL_GPL(clk_enable);
EXPORT_SYMBOL_GPL(clk_disable);
EXPORT_SYMBOL_GPL(__clk_enable);
EXPORT_SYMBOL_GPL(__clk_disable);
EXPORT_SYMBOL_GPL(clk_get_rate);
EXPORT_SYMBOL_GPL(clk_set_rate);
EXPORT_SYMBOL_GPL(clk_recalc_rate);