arch/sh/kernel/cpu/clock.c - linux - Git at Google

 /*
  * arch/sh/kernel/cpu/clock.c - SuperH clock framework
  *
  *  Copyright (C) 2005, 2006, 2007  Paul Mundt
  *
  * This clock framework is derived from the OMAP version by:
  *
  *	Copyright (C) 2004 - 2005 Nokia Corporation
  *	Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
  *
  *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.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 <linux/platform_device.h>
 #include <linux/proc_fs.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);
 		if (unlikely(clkp->flags & CLK_RATE_PROPAGATES))
 			propagate_rate(clkp);
 	}
 }

 static 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);

 	kref_get(&clk->kref);

 	if (clk->flags & CLK_ALWAYS_ENABLED)
 		return 0;

 	if (likely(clk->ops && clk->ops->enable))
 		clk->ops->enable(clk);

 	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;
 }
 EXPORT_SYMBOL_GPL(clk_enable);

 static void clk_kref_release(struct kref *kref)
 {
 	/* Nothing to do */
 }

 static void __clk_disable(struct clk *clk)
 {
 	int count = kref_put(&clk->kref, clk_kref_release);

 	if (clk->flags & CLK_ALWAYS_ENABLED)
 		return;

 	if (!count) {	/* count reaches zero, disable the clock */
 		if (likely(clk->ops && clk->ops->disable))
 			clk->ops->disable(clk);
 	}
 }

 void clk_disable(struct clk *clk)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&clock_lock, flags);
 	__clk_disable(clk);
 	spin_unlock_irqrestore(&clock_lock, flags);
 }
 EXPORT_SYMBOL_GPL(clk_disable);

 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);

 	if (clk->flags & CLK_ALWAYS_ENABLED) {
 		pr_debug( "Clock '%s' is ALWAYS_ENABLED\n", clk->name);
 		if (clk->ops && clk->ops->init)
 			clk->ops->init(clk);
 		if (clk->ops && clk->ops->enable)
 			clk->ops->enable(clk);
 		pr_debug( "Enabled.");
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(clk_register);

 void clk_unregister(struct clk *clk)
 {
 	mutex_lock(&clock_list_sem);
 	list_del(&clk->node);
 	mutex_unlock(&clock_list_sem);
 }
 EXPORT_SYMBOL_GPL(clk_unregister);

 unsigned long clk_get_rate(struct clk *clk)
 {
 	return clk->rate;
 }
 EXPORT_SYMBOL_GPL(clk_get_rate);

 int clk_set_rate(struct clk *clk, unsigned long rate)
 {
 	return clk_set_rate_ex(clk, rate, 0);
 }
 EXPORT_SYMBOL_GPL(clk_set_rate);

 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 {
 	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, algo_id);
 		spin_unlock_irqrestore(&clock_lock, flags);
 	}

 	if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
 		propagate_rate(clk);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(clk_set_rate_ex);

 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);
 }
 EXPORT_SYMBOL_GPL(clk_recalc_rate);

 long clk_round_rate(struct clk *clk, unsigned long rate)
 {
 	if (likely(clk->ops && clk->ops->round_rate)) {
 		unsigned long flags, rounded;

 		spin_lock_irqsave(&clock_lock, flags);
 		rounded = clk->ops->round_rate(clk, rate);
 		spin_unlock_irqrestore(&clock_lock, flags);

 		return rounded;
 	}

 	return clk_get_rate(clk);
 }
 EXPORT_SYMBOL_GPL(clk_round_rate);

 /*
  * Returns a clock. Note that we first try to use device id on the bus
  * and clock name. If this fails, we try to use clock name only.
  */
 struct clk *clk_get(struct device *dev, const char *id)
 {
 	struct clk *p, *clk = ERR_PTR(-ENOENT);
 	int idno;

 	if (dev == NULL || dev->bus != &platform_bus_type)
 		idno = -1;
 	else
 		idno = to_platform_device(dev)->id;

 	mutex_lock(&clock_list_sem);
 	list_for_each_entry(p, &clock_list, node) {
 		if (p->id == idno &&
 		    strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 			clk = p;
 			goto found;
 		}
 	}

 	list_for_each_entry(p, &clock_list, node) {
 		if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 			clk = p;
 			break;
 		}
 	}

 found:
 	mutex_unlock(&clock_list_sem);

 	return clk;
 }
 EXPORT_SYMBOL_GPL(clk_get);

 void clk_put(struct clk *clk)
 {
 	if (clk && !IS_ERR(clk))
 		module_put(clk->owner);
 }
 EXPORT_SYMBOL_GPL(clk_put);

 void __init __attribute__ ((weak))
 arch_init_clk_ops(struct clk_ops **ops, int type)
 {
 }

 void __init __attribute__ ((weak))
 arch_clk_init(void)
 {
 }

 static int show_clocks(char *buf, char **start, off_t off,
 		       int len, int *eof, void *data)
 {
 	struct clk *clk;
 	char *p = buf;

 	list_for_each_entry_reverse(clk, &clock_list, node) {
 		unsigned long rate = clk_get_rate(clk);

 		p += sprintf(p, "%-12s\t: %ld.%02ldMHz\t%s\n", clk->name,
 			     rate / 1000000, (rate % 1000000) / 10000,
 			     ((clk->flags & CLK_ALWAYS_ENABLED) ||
 			      (atomic_read(&clk->kref.refcount) != 1)) ?
 			     "enabled" : "disabled");
 	}

 	return p - buf;
 }

 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);
 	}

 	arch_clk_init();

 	/* Kick the child clocks.. */
 	propagate_rate(&master_clk);
 	propagate_rate(&bus_clk);

 	return ret;
 }

 static int __init clk_proc_init(void)
 {
 	struct proc_dir_entry *p;
 	p = create_proc_read_entry("clocks", S_IRUSR, NULL,
 				   show_clocks, NULL);
 	if (unlikely(!p))
 		return -EINVAL;

 	return 0;
 }
 subsys_initcall(clk_proc_init);
	/*
	* arch/sh/kernel/cpu/clock.c - SuperH clock framework
	*
	* Copyright (C) 2005, 2006, 2007 Paul Mundt
	*
	* This clock framework is derived from the OMAP version by:
	*
	* Copyright (C) 2004 - 2005 Nokia Corporation
	* Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
	*
	* Modified for omap shared clock framework by Tony Lindgren <tony@atomide.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 <linux/platform_device.h>
	#include <linux/proc_fs.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);
	if (unlikely(clkp->flags & CLK_RATE_PROPAGATES))
	propagate_rate(clkp);
	}
	}

	static 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);

	kref_get(&clk->kref);

	if (clk->flags & CLK_ALWAYS_ENABLED)
	return 0;

	if (likely(clk->ops && clk->ops->enable))
	clk->ops->enable(clk);

	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;
	}
	EXPORT_SYMBOL_GPL(clk_enable);

	static void clk_kref_release(struct kref *kref)
	{
	/* Nothing to do */
	}

	static void __clk_disable(struct clk *clk)
	{
	int count = kref_put(&clk->kref, clk_kref_release);

	if (clk->flags & CLK_ALWAYS_ENABLED)
	return;

	if (!count) { /* count reaches zero, disable the clock */
	if (likely(clk->ops && clk->ops->disable))
	clk->ops->disable(clk);
	}
	}

	void clk_disable(struct clk *clk)
	{
	unsigned long flags;

	spin_lock_irqsave(&clock_lock, flags);
	__clk_disable(clk);
	spin_unlock_irqrestore(&clock_lock, flags);
	}
	EXPORT_SYMBOL_GPL(clk_disable);

	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);

	if (clk->flags & CLK_ALWAYS_ENABLED) {
	pr_debug( "Clock '%s' is ALWAYS_ENABLED\n", clk->name);
	if (clk->ops && clk->ops->init)
	clk->ops->init(clk);
	if (clk->ops && clk->ops->enable)
	clk->ops->enable(clk);
	pr_debug( "Enabled.");
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(clk_register);

	void clk_unregister(struct clk *clk)
	{
	mutex_lock(&clock_list_sem);
	list_del(&clk->node);
	mutex_unlock(&clock_list_sem);
	}
	EXPORT_SYMBOL_GPL(clk_unregister);

	unsigned long clk_get_rate(struct clk *clk)
	{
	return clk->rate;
	}
	EXPORT_SYMBOL_GPL(clk_get_rate);

	int clk_set_rate(struct clk *clk, unsigned long rate)
	{
	return clk_set_rate_ex(clk, rate, 0);
	}
	EXPORT_SYMBOL_GPL(clk_set_rate);

	int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
	{
	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, algo_id);
	spin_unlock_irqrestore(&clock_lock, flags);
	}

	if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
	propagate_rate(clk);

	return ret;
	}
	EXPORT_SYMBOL_GPL(clk_set_rate_ex);

	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);
	}
	EXPORT_SYMBOL_GPL(clk_recalc_rate);

	long clk_round_rate(struct clk *clk, unsigned long rate)
	{
	if (likely(clk->ops && clk->ops->round_rate)) {
	unsigned long flags, rounded;

	spin_lock_irqsave(&clock_lock, flags);
	rounded = clk->ops->round_rate(clk, rate);
	spin_unlock_irqrestore(&clock_lock, flags);

	return rounded;
	}

	return clk_get_rate(clk);
	}
	EXPORT_SYMBOL_GPL(clk_round_rate);

	/*
	* Returns a clock. Note that we first try to use device id on the bus
	* and clock name. If this fails, we try to use clock name only.
	*/
	struct clk clk_get(struct device dev, const char *id)
	{
	struct clk p, clk = ERR_PTR(-ENOENT);
	int idno;

	if (dev == NULL \|\| dev->bus != &platform_bus_type)
	idno = -1;
	else
	idno = to_platform_device(dev)->id;

	mutex_lock(&clock_list_sem);
	list_for_each_entry(p, &clock_list, node) {
	if (p->id == idno &&
	strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
	clk = p;
	goto found;
	}
	}

	list_for_each_entry(p, &clock_list, node) {
	if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
	clk = p;
	break;
	}
	}

	found:
	mutex_unlock(&clock_list_sem);

	return clk;
	}
	EXPORT_SYMBOL_GPL(clk_get);

	void clk_put(struct clk *clk)
	{
	if (clk && !IS_ERR(clk))
	module_put(clk->owner);
	}
	EXPORT_SYMBOL_GPL(clk_put);

	void __init __attribute__ ((weak))
	arch_init_clk_ops(struct clk_ops **ops, int type)
	{
	}

	void __init __attribute__ ((weak))
	arch_clk_init(void)
	{
	}

	static int show_clocks(char buf, char *start, off_t off,
	int len, int eof, void data)
	{
	struct clk *clk;
	char *p = buf;

	list_for_each_entry_reverse(clk, &clock_list, node) {
	unsigned long rate = clk_get_rate(clk);

	p += sprintf(p, "%-12s\t: %ld.%02ldMHz\t%s\n", clk->name,
	rate / 1000000, (rate % 1000000) / 10000,
	((clk->flags & CLK_ALWAYS_ENABLED) \|\|
	(atomic_read(&clk->kref.refcount) != 1)) ?
	"enabled" : "disabled");
	}

	return p - buf;
	}

	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);
	}

	arch_clk_init();

	/* Kick the child clocks.. */
	propagate_rate(&master_clk);
	propagate_rate(&bus_clk);

	return ret;
	}

	static int __init clk_proc_init(void)
	{
	struct proc_dir_entry *p;
	p = create_proc_read_entry("clocks", S_IRUSR, NULL,
	show_clocks, NULL);
	if (unlikely(!p))
	return -EINVAL;

	return 0;
	}
	subsys_initcall(clk_proc_init);