/*
 *  linux/arch/arm/mach-omap2/clock.c
 *
 *  Copyright (C) 2005-2008 Texas Instruments, Inc.
 *  Copyright (C) 2004-2008 Nokia Corporation
 *
 *  Contacts:
 *  Richard Woodruff <r-woodruff2@ti.com>
 *  Paul Walmsley
 *
 * 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.
 */
#undef DEBUG

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/bitops.h>

#include <plat/clock.h>
#include <plat/clockdomain.h>
#include <plat/cpu.h>
#include <plat/prcm.h>

#include "clock.h"
#include "prm.h"
#include "prm-regbits-24xx.h"
#include "cm.h"
#include "cm-regbits-24xx.h"
#include "cm-regbits-34xx.h"

u8 cpu_mask;

/*-------------------------------------------------------------------------
 * OMAP2/3/4 specific clock functions
 *-------------------------------------------------------------------------*/

/* Private functions */

/**
 * _omap2_module_wait_ready - wait for an OMAP module to leave IDLE
 * @clk: struct clk * belonging to the module
 *
 * If the necessary clocks for the OMAP hardware IP block that
 * corresponds to clock @clk are enabled, then wait for the module to
 * indicate readiness (i.e., to leave IDLE).  This code does not
 * belong in the clock code and will be moved in the medium term to
 * module-dependent code.  No return value.
 */
static void _omap2_module_wait_ready(struct clk *clk)
{
	void __iomem *companion_reg, *idlest_reg;
	u8 other_bit, idlest_bit;

	/* Not all modules have multiple clocks that their IDLEST depends on */
	if (clk->ops->find_companion) {
		clk->ops->find_companion(clk, &companion_reg, &other_bit);
		if (!(__raw_readl(companion_reg) & (1 << other_bit)))
			return;
	}

	clk->ops->find_idlest(clk, &idlest_reg, &idlest_bit);

	omap2_cm_wait_idlest(idlest_reg, (1 << idlest_bit), clk->name);
}

/* Enables clock without considering parent dependencies or use count
 * REVISIT: Maybe change this to use clk->enable like on omap1?
 */
static int _omap2_clk_enable(struct clk *clk)
{
	return clk->ops->enable(clk);
}

/* Disables clock without considering parent dependencies or use count */
static void _omap2_clk_disable(struct clk *clk)
{
	clk->ops->disable(clk);
}

/* Public functions */

/**
 * omap2xxx_clk_commit - commit clock parent/rate changes in hardware
 * @clk: struct clk *
 *
 * If @clk has the DELAYED_APP flag set, meaning that parent/rate changes
 * don't take effect until the VALID_CONFIG bit is written, write the
 * VALID_CONFIG bit and wait for the write to complete.  No return value.
 */
void omap2xxx_clk_commit(struct clk *clk)
{
	if (!cpu_is_omap24xx())
		return;

	if (!(clk->flags & DELAYED_APP))
		return;

	prm_write_mod_reg(OMAP24XX_VALID_CONFIG, OMAP24XX_GR_MOD,
		OMAP2_PRCM_CLKCFG_CTRL_OFFSET);
	/* OCP barrier */
	prm_read_mod_reg(OMAP24XX_GR_MOD, OMAP2_PRCM_CLKCFG_CTRL_OFFSET);
}

/**
 * omap2_init_clk_clkdm - look up a clockdomain name, store pointer in clk
 * @clk: OMAP clock struct ptr to use
 *
 * Convert a clockdomain name stored in a struct clk 'clk' into a
 * clockdomain pointer, and save it into the struct clk.  Intended to be
 * called during clk_register().  No return value.
 */
void omap2_init_clk_clkdm(struct clk *clk)
{
	struct clockdomain *clkdm;

	if (!clk->clkdm_name)
		return;

	clkdm = clkdm_lookup(clk->clkdm_name);
	if (clkdm) {
		pr_debug("clock: associated clk %s to clkdm %s\n",
			 clk->name, clk->clkdm_name);
		clk->clkdm = clkdm;
	} else {
		pr_debug("clock: could not associate clk %s to "
			 "clkdm %s\n", clk->name, clk->clkdm_name);
	}
}

/**
 * omap2_clk_dflt_find_companion - find companion clock to @clk
 * @clk: struct clk * to find the companion clock of
 * @other_reg: void __iomem ** to return the companion clock CM_*CLKEN va in
 * @other_bit: u8 ** to return the companion clock bit shift in
 *
 * Note: We don't need special code here for INVERT_ENABLE for the
 * time being since INVERT_ENABLE only applies to clocks enabled by
 * CM_CLKEN_PLL
 *
 * Convert CM_ICLKEN* <-> CM_FCLKEN*.  This conversion assumes it's
 * just a matter of XORing the bits.
 *
 * Some clocks don't have companion clocks.  For example, modules with
 * only an interface clock (such as MAILBOXES) don't have a companion
 * clock.  Right now, this code relies on the hardware exporting a bit
 * in the correct companion register that indicates that the
 * nonexistent 'companion clock' is active.  Future patches will
 * associate this type of code with per-module data structures to
 * avoid this issue, and remove the casts.  No return value.
 */
void omap2_clk_dflt_find_companion(struct clk *clk, void __iomem **other_reg,
				   u8 *other_bit)
{
	u32 r;

	/*
	 * Convert CM_ICLKEN* <-> CM_FCLKEN*.  This conversion assumes
	 * it's just a matter of XORing the bits.
	 */
	r = ((__force u32)clk->enable_reg ^ (CM_FCLKEN ^ CM_ICLKEN));

	*other_reg = (__force void __iomem *)r;
	*other_bit = clk->enable_bit;
}

/**
 * omap2_clk_dflt_find_idlest - find CM_IDLEST reg va, bit shift for @clk
 * @clk: struct clk * to find IDLEST info for
 * @idlest_reg: void __iomem ** to return the CM_IDLEST va in
 * @idlest_bit: u8 ** to return the CM_IDLEST bit shift in
 *
 * Return the CM_IDLEST register address and bit shift corresponding
 * to the module that "owns" this clock.  This default code assumes
 * that the CM_IDLEST bit shift is the CM_*CLKEN bit shift, and that
 * the IDLEST register address ID corresponds to the CM_*CLKEN
 * register address ID (e.g., that CM_FCLKEN2 corresponds to
 * CM_IDLEST2).  This is not true for all modules.  No return value.
 */
void omap2_clk_dflt_find_idlest(struct clk *clk, void __iomem **idlest_reg,
				u8 *idlest_bit)
{
	u32 r;

	r = (((__force u32)clk->enable_reg & ~0xf0) | 0x20);
	*idlest_reg = (__force void __iomem *)r;
	*idlest_bit = clk->enable_bit;
}

int omap2_dflt_clk_enable(struct clk *clk)
{
	u32 v;

	if (unlikely(clk->enable_reg == NULL)) {
		pr_err("clock.c: Enable for %s without enable code\n",
		       clk->name);
		return 0; /* REVISIT: -EINVAL */
	}

	v = __raw_readl(clk->enable_reg);
	if (clk->flags & INVERT_ENABLE)
		v &= ~(1 << clk->enable_bit);
	else
		v |= (1 << clk->enable_bit);
	__raw_writel(v, clk->enable_reg);
	v = __raw_readl(clk->enable_reg); /* OCP barrier */

	if (clk->ops->find_idlest)
		_omap2_module_wait_ready(clk);

	return 0;
}

void omap2_dflt_clk_disable(struct clk *clk)
{
	u32 v;

	if (!clk->enable_reg) {
		/*
		 * 'Independent' here refers to a clock which is not
		 * controlled by its parent.
		 */
		printk(KERN_ERR "clock: clk_disable called on independent "
		       "clock %s which has no enable_reg\n", clk->name);
		return;
	}

	v = __raw_readl(clk->enable_reg);
	if (clk->flags & INVERT_ENABLE)
		v |= (1 << clk->enable_bit);
	else
		v &= ~(1 << clk->enable_bit);
	__raw_writel(v, clk->enable_reg);
	/* No OCP barrier needed here since it is a disable operation */
}

const struct clkops clkops_omap2_dflt_wait = {
	.enable		= omap2_dflt_clk_enable,
	.disable	= omap2_dflt_clk_disable,
	.find_companion	= omap2_clk_dflt_find_companion,
	.find_idlest	= omap2_clk_dflt_find_idlest,
};

const struct clkops clkops_omap2_dflt = {
	.enable		= omap2_dflt_clk_enable,
	.disable	= omap2_dflt_clk_disable,
};

void omap2_clk_disable(struct clk *clk)
{
	if (clk->usecount > 0 && !(--clk->usecount)) {
		_omap2_clk_disable(clk);
		if (clk->parent)
			omap2_clk_disable(clk->parent);
		if (clk->clkdm)
			omap2_clkdm_clk_disable(clk->clkdm, clk);

	}
}

int omap2_clk_enable(struct clk *clk)
{
	int ret = 0;

	if (clk->usecount++ == 0) {
		if (clk->clkdm)
			omap2_clkdm_clk_enable(clk->clkdm, clk);

		if (clk->parent) {
			ret = omap2_clk_enable(clk->parent);
			if (ret)
				goto err;
		}

		ret = _omap2_clk_enable(clk);
		if (ret) {
			if (clk->parent)
				omap2_clk_disable(clk->parent);

			goto err;
		}
	}
	return ret;

err:
	if (clk->clkdm)
		omap2_clkdm_clk_disable(clk->clkdm, clk);
	clk->usecount--;
	return ret;
}

/* Set the clock rate for a clock source */
int omap2_clk_set_rate(struct clk *clk, unsigned long rate)
{
	int ret = -EINVAL;

	pr_debug("clock: set_rate for clock %s to rate %ld\n", clk->name, rate);

	/* CONFIG_PARTICIPANT clocks are changed only in sets via the
	   rate table mechanism, driven by mpu_speed  */
	if (clk->flags & CONFIG_PARTICIPANT)
		return -EINVAL;

	/* dpll_ck, core_ck, virt_prcm_set; plus all clksel clocks */
	if (clk->set_rate)
		ret = clk->set_rate(clk, rate);

	return ret;
}

int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent)
{
	if (clk->flags & CONFIG_PARTICIPANT)
		return -EINVAL;

	if (!clk->clksel)
		return -EINVAL;

	return omap2_clksel_set_parent(clk, new_parent);
}

/*-------------------------------------------------------------------------
 * Omap2 clock reset and init functions
 *-------------------------------------------------------------------------*/

#ifdef CONFIG_OMAP_RESET_CLOCKS
void omap2_clk_disable_unused(struct clk *clk)
{
	u32 regval32, v;

	v = (clk->flags & INVERT_ENABLE) ? (1 << clk->enable_bit) : 0;

	regval32 = __raw_readl(clk->enable_reg);
	if ((regval32 & (1 << clk->enable_bit)) == v)
		return;

	printk(KERN_DEBUG "Disabling unused clock \"%s\"\n", clk->name);
	if (cpu_is_omap34xx()) {
		omap2_clk_enable(clk);
		omap2_clk_disable(clk);
	} else
		_omap2_clk_disable(clk);
	if (clk->clkdm != NULL)
		pwrdm_clkdm_state_switch(clk->clkdm);
}
#endif

/* Common data */

struct clk_functions omap2_clk_functions = {
	.clk_enable		= omap2_clk_enable,
	.clk_disable		= omap2_clk_disable,
	.clk_round_rate		= omap2_clk_round_rate,
	.clk_set_rate		= omap2_clk_set_rate,
	.clk_set_parent		= omap2_clk_set_parent,
	.clk_disable_unused	= omap2_clk_disable_unused,
#ifdef CONFIG_CPU_FREQ
	/* These will be removed when the OPP code is integrated */
	.clk_init_cpufreq_table	= omap2_clk_init_cpufreq_table,
	.clk_exit_cpufreq_table	= omap2_clk_exit_cpufreq_table,
#endif
};