/*
 *  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/module.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/platform_device.h>
#include <linux/cpufreq.h>
#include <linux/debugfs.h>
#include <linux/io.h>

#include <mach/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 = 0;

        if (clk == NULL || IS_ERR(clk))
                return -EINVAL;

        spin_lock_irqsave(&clockfw_lock, flags);
        if (arch_clock->clk_enable)
                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;

        spin_lock_irqsave(&clockfw_lock, flags);
        if (clk->usecount == 0) {
                printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
                       clk->name);
                WARN_ON(1);
                goto out;
        }

        if (arch_clock->clk_disable)
                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 = 0;

        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 = 0;

        if (clk == NULL || IS_ERR(clk))
                return ret;

        spin_lock_irqsave(&clockfw_lock, flags);
        if (arch_clock->clk_round_rate)
                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;

        spin_lock_irqsave(&clockfw_lock, flags);
        if (arch_clock->clk_set_rate)
                ret = arch_clock->clk_set_rate(clk, rate);
        if (ret == 0) {
                if (clk->recalc)
                        clk->rate = clk->recalc(clk);
                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;

        spin_lock_irqsave(&clockfw_lock, flags);
        if (clk->usecount == 0) {
                if (arch_clock->clk_set_parent)
                        ret = arch_clock->clk_set_parent(clk, parent);
                if (ret == 0) {
                        if (clk->recalc)
                                clk->rate = clk->recalc(clk);
                        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
 *-------------------------------------------------------------------------*/

unsigned 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;
}

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_init_one - 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_init_one(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);
        }
}
EXPORT_SYMBOL(clk_enable_init_clocks);

/*
 * 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,
};

#ifdef CONFIG_CPU_FREQ
void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
{
        unsigned long flags;

        spin_lock_irqsave(&clockfw_lock, flags);
        if (arch_clock->clk_init_cpufreq_table)
                arch_clock->clk_init_cpufreq_table(table);
        spin_unlock_irqrestore(&clockfw_lock, flags);
}
EXPORT_SYMBOL(clk_init_cpufreq_table);
#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;

        list_for_each_entry(ck, &clocks, node) {
                if (ck->ops == &clkops_null)
                        continue;

                if (ck->usecount > 0 || ck->enable_reg == 0)
                        continue;

                spin_lock_irqsave(&clockfw_lock, flags);
                if (arch_clock->clk_disable_unused)
                        arch_clock->clk_disable_unused(ck);
                spin_unlock_irqrestore(&clockfw_lock, flags);
        }

        return 0;
}
late_initcall(clk_disable_unused);
#endif

int __init clk_init(struct clk_functions * custom_clocks)
{
        if (!custom_clocks) {
                printk(KERN_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;
        struct clk *pa = c->parent;
        char s[255];
        char *p = s;

        p += sprintf(p, "%s", c->name);
        if (c->id != 0)
                sprintf(p, ":%d", c->id);
        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(child, &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(clk_debugfs_root); /* REVISIT: Cleanup correctly */
        return err;
}
late_initcall(clk_debugfs_init);

#endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */