/*
 *  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
 *-------------------------------------------------------------------------*/

/**
 * _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.
 */
static 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_init_clksel_parent - set a clksel clk's parent field from the hardware
 * @clk: OMAP clock struct ptr to use
 *
 * Given a pointer to a source-selectable struct clk, read the hardware
 * register and determine what its parent is currently set to.  Update the
 * clk->parent field with the appropriate clk ptr.
 */
void omap2_init_clksel_parent(struct clk *clk)
{
	const struct clksel *clks;
	const struct clksel_rate *clkr;
	u32 r, found = 0;

	if (!clk->clksel)
		return;

	r = __raw_readl(clk->clksel_reg) & clk->clksel_mask;
	r >>= __ffs(clk->clksel_mask);

	for (clks = clk->clksel; clks->parent && !found; clks++) {
		for (clkr = clks->rates; clkr->div && !found; clkr++) {
			if ((clkr->flags & cpu_mask) && (clkr->val == r)) {
				if (clk->parent != clks->parent) {
					pr_debug("clock: inited %s parent "
						 "to %s (was %s)\n",
						 clk->name, clks->parent->name,
						 ((clk->parent) ?
						  clk->parent->name : "NULL"));
					clk_reparent(clk, clks->parent);
				};
				found = 1;
			}
		}
	}

	if (!found)
		printk(KERN_ERR "clock: init parent: could not find "
		       "regval %0x for clock %s\n", r,  clk->name);

	return;
}

/**
 * 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;
}

/**
 * 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);
}

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,
};

/* 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);
}

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;
}

/*
 * Used for clocks that are part of CLKSEL_xyz governed clocks.
 * REVISIT: Maybe change to use clk->enable() functions like on omap1?
 */
unsigned long omap2_clksel_recalc(struct clk *clk)
{
	unsigned long rate;
	u32 div = 0;

	pr_debug("clock: recalc'ing clksel clk %s\n", clk->name);

	div = omap2_clksel_get_divisor(clk);
	if (div == 0)
		return clk->rate;

	rate = clk->parent->rate / div;

	pr_debug("clock: new clock rate is %ld (div %d)\n", rate, div);

	return rate;
}

/**
 * omap2_get_clksel_by_parent - return clksel struct for a given clk & parent
 * @clk: OMAP struct clk ptr to inspect
 * @src_clk: OMAP struct clk ptr of the parent clk to search for
 *
 * Scan the struct clksel array associated with the clock to find
 * the element associated with the supplied parent clock address.
 * Returns a pointer to the struct clksel on success or NULL on error.
 */
static const struct clksel *omap2_get_clksel_by_parent(struct clk *clk,
						       struct clk *src_clk)
{
	const struct clksel *clks;

	if (!clk->clksel)
		return NULL;

	for (clks = clk->clksel; clks->parent; clks++) {
		if (clks->parent == src_clk)
			break; /* Found the requested parent */
	}

	if (!clks->parent) {
		printk(KERN_ERR "clock: Could not find parent clock %s in "
		       "clksel array of clock %s\n", src_clk->name,
		       clk->name);
		return NULL;
	}

	return clks;
}

/**
 * omap2_clksel_round_rate_div - find divisor for the given clock and rate
 * @clk: OMAP struct clk to use
 * @target_rate: desired clock rate
 * @new_div: ptr to where we should store the divisor
 *
 * Finds 'best' divider value in an array based on the source and target
 * rates.  The divider array must be sorted with smallest divider first.
 * Note that this will not work for clocks which are part of CONFIG_PARTICIPANT,
 * they are only settable as part of virtual_prcm set.
 *
 * Returns the rounded clock rate or returns 0xffffffff on error.
 */
u32 omap2_clksel_round_rate_div(struct clk *clk, unsigned long target_rate,
				u32 *new_div)
{
	unsigned long test_rate;
	const struct clksel *clks;
	const struct clksel_rate *clkr;
	u32 last_div = 0;

	pr_debug("clock: clksel_round_rate_div: %s target_rate %ld\n",
		 clk->name, target_rate);

	*new_div = 1;

	clks = omap2_get_clksel_by_parent(clk, clk->parent);
	if (!clks)
		return ~0;

	for (clkr = clks->rates; clkr->div; clkr++) {
		if (!(clkr->flags & cpu_mask))
		    continue;

		/* Sanity check */
		if (clkr->div <= last_div)
			pr_err("clock: clksel_rate table not sorted "
			       "for clock %s", clk->name);

		last_div = clkr->div;

		test_rate = clk->parent->rate / clkr->div;

		if (test_rate <= target_rate)
			break; /* found it */
	}

	if (!clkr->div) {
		pr_err("clock: Could not find divisor for target "
		       "rate %ld for clock %s parent %s\n", target_rate,
		       clk->name, clk->parent->name);
		return ~0;
	}

	*new_div = clkr->div;

	pr_debug("clock: new_div = %d, new_rate = %ld\n", *new_div,
		 (clk->parent->rate / clkr->div));

	return (clk->parent->rate / clkr->div);
}

/**
 * omap2_clksel_round_rate - find rounded rate for the given clock and rate
 * @clk: OMAP struct clk to use
 * @target_rate: desired clock rate
 *
 * Compatibility wrapper for OMAP clock framework
 * Finds best target rate based on the source clock and possible dividers.
 * rates. The divider array must be sorted with smallest divider first.
 * Note that this will not work for clocks which are part of CONFIG_PARTICIPANT,
 * they are only settable as part of virtual_prcm set.
 *
 * Returns the rounded clock rate or returns 0xffffffff on error.
 */
long omap2_clksel_round_rate(struct clk *clk, unsigned long target_rate)
{
	u32 new_div;

	return omap2_clksel_round_rate_div(clk, target_rate, &new_div);
}


/* Given a clock and a rate apply a clock specific rounding function */
long omap2_clk_round_rate(struct clk *clk, unsigned long rate)
{
	if (clk->round_rate)
		return clk->round_rate(clk, rate);

	if (clk->flags & RATE_FIXED)
		printk(KERN_ERR "clock: generic omap2_clk_round_rate called "
		       "on fixed-rate clock %s\n", clk->name);

	return clk->rate;
}

/**
 * omap2_clksel_to_divisor() - turn clksel field value into integer divider
 * @clk: OMAP struct clk to use
 * @field_val: register field value to find
 *
 * Given a struct clk of a rate-selectable clksel clock, and a register field
 * value to search for, find the corresponding clock divisor.  The register
 * field value should be pre-masked and shifted down so the LSB is at bit 0
 * before calling.  Returns 0 on error
 */
u32 omap2_clksel_to_divisor(struct clk *clk, u32 field_val)
{
	const struct clksel *clks;
	const struct clksel_rate *clkr;

	clks = omap2_get_clksel_by_parent(clk, clk->parent);
	if (!clks)
		return 0;

	for (clkr = clks->rates; clkr->div; clkr++) {
		if ((clkr->flags & cpu_mask) && (clkr->val == field_val))
			break;
	}

	if (!clkr->div) {
		printk(KERN_ERR "clock: Could not find fieldval %d for "
		       "clock %s parent %s\n", field_val, clk->name,
		       clk->parent->name);
		return 0;
	}

	return clkr->div;
}

/**
 * omap2_divisor_to_clksel() - turn clksel integer divisor into a field value
 * @clk: OMAP struct clk to use
 * @div: integer divisor to search for
 *
 * Given a struct clk of a rate-selectable clksel clock, and a clock divisor,
 * find the corresponding register field value.  The return register value is
 * the value before left-shifting.  Returns ~0 on error
 */
u32 omap2_divisor_to_clksel(struct clk *clk, u32 div)
{
	const struct clksel *clks;
	const struct clksel_rate *clkr;

	/* should never happen */
	WARN_ON(div == 0);

	clks = omap2_get_clksel_by_parent(clk, clk->parent);
	if (!clks)
		return ~0;

	for (clkr = clks->rates; clkr->div; clkr++) {
		if ((clkr->flags & cpu_mask) && (clkr->div == div))
			break;
	}

	if (!clkr->div) {
		printk(KERN_ERR "clock: Could not find divisor %d for "
		       "clock %s parent %s\n", div, clk->name,
		       clk->parent->name);
		return ~0;
	}

	return clkr->val;
}

/**
 * omap2_clksel_get_divisor - get current divider applied to parent clock.
 * @clk: OMAP struct clk to use.
 *
 * Returns the integer divisor upon success or 0 on error.
 */
u32 omap2_clksel_get_divisor(struct clk *clk)
{
	u32 v;

	if (!clk->clksel_mask)
		return 0;

	v = __raw_readl(clk->clksel_reg) & clk->clksel_mask;
	v >>= __ffs(clk->clksel_mask);

	return omap2_clksel_to_divisor(clk, v);
}

int omap2_clksel_set_rate(struct clk *clk, unsigned long rate)
{
	u32 v, field_val, validrate, new_div = 0;

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

	validrate = omap2_clksel_round_rate_div(clk, rate, &new_div);
	if (validrate != rate)
		return -EINVAL;

	field_val = omap2_divisor_to_clksel(clk, new_div);
	if (field_val == ~0)
		return -EINVAL;

	v = __raw_readl(clk->clksel_reg);
	v &= ~clk->clksel_mask;
	v |= field_val << __ffs(clk->clksel_mask);
	__raw_writel(v, clk->clksel_reg);
	v = __raw_readl(clk->clksel_reg); /* OCP barrier */

	clk->rate = clk->parent->rate / new_div;

	_omap2xxx_clk_commit(clk);

	return 0;
}


/* 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;
}

/*
 * Converts encoded control register address into a full address
 * On error, the return value (parent_div) will be 0.
 */
static u32 _omap2_clksel_get_src_field(struct clk *src_clk, struct clk *clk,
				       u32 *field_val)
{
	const struct clksel *clks;
	const struct clksel_rate *clkr;

	clks = omap2_get_clksel_by_parent(clk, src_clk);
	if (!clks)
		return 0;

	for (clkr = clks->rates; clkr->div; clkr++) {
		if (clkr->flags & cpu_mask && clkr->flags & DEFAULT_RATE)
			break; /* Found the default rate for this platform */
	}

	if (!clkr->div) {
		printk(KERN_ERR "clock: Could not find default rate for "
		       "clock %s parent %s\n", clk->name,
		       src_clk->parent->name);
		return 0;
	}

	/* Should never happen.  Add a clksel mask to the struct clk. */
	WARN_ON(clk->clksel_mask == 0);

	*field_val = clkr->val;

	return clkr->div;
}

int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent)
{
	u32 field_val, v, parent_div;

	if (clk->flags & CONFIG_PARTICIPANT)
		return -EINVAL;

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

	parent_div = _omap2_clksel_get_src_field(new_parent, clk, &field_val);
	if (!parent_div)
		return -EINVAL;

	/* Set new source value (previous dividers if any in effect) */
	v = __raw_readl(clk->clksel_reg);
	v &= ~clk->clksel_mask;
	v |= field_val << __ffs(clk->clksel_mask);
	__raw_writel(v, clk->clksel_reg);
	v = __raw_readl(clk->clksel_reg);    /* OCP barrier */

	_omap2xxx_clk_commit(clk);

	clk_reparent(clk, new_parent);

	/* CLKSEL clocks follow their parents' rates, divided by a divisor */
	clk->rate = new_parent->rate;

	if (parent_div > 0)
		clk->rate /= parent_div;

	pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
		 clk->name, clk->parent->name, clk->rate);

	return 0;
}

/*-------------------------------------------------------------------------
 * 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