/*
 * OMAP3/4 - specific DPLL control functions
 *
 * Copyright (C) 2009-2010 Texas Instruments, Inc.
 * Copyright (C) 2009-2010 Nokia Corporation
 *
 * Written by Paul Walmsley
 * Testing and integration fixes by Jouni Högander
 *
 * 36xx support added by Vishwanath BS, Richard Woodruff, and Nishanth
 * Menon
 *
 * Parts of this code are based on code written by
 * Richard Woodruff, Tony Lindgren, Tuukka Tikkanen, Karthik Dasu
 *
 * 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/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 <linux/clkdev.h>

#include "soc.h"
#include "clockdomain.h"
#include "clock.h"
#include "cm2xxx_3xxx.h"
#include "cm-regbits-34xx.h"

/* CM_AUTOIDLE_PLL*.AUTO_* bit values */
#define DPLL_AUTOIDLE_DISABLE			0x0
#define DPLL_AUTOIDLE_LOW_POWER_STOP		0x1

#define MAX_DPLL_WAIT_TRIES		1000000

/* Private functions */

/* _omap3_dpll_write_clken - write clken_bits arg to a DPLL's enable bits */
static void _omap3_dpll_write_clken(struct clk_hw_omap *clk, u8 clken_bits)
{
	const struct dpll_data *dd;
	u32 v;

	dd = clk->dpll_data;

	v = __raw_readl(dd->control_reg);
	v &= ~dd->enable_mask;
	v |= clken_bits << __ffs(dd->enable_mask);
	__raw_writel(v, dd->control_reg);
}

/* _omap3_wait_dpll_status: wait for a DPLL to enter a specific state */
static int _omap3_wait_dpll_status(struct clk_hw_omap *clk, u8 state)
{
	const struct dpll_data *dd;
	int i = 0;
	int ret = -EINVAL;
	const char *clk_name;

	dd = clk->dpll_data;
	clk_name = __clk_get_name(clk->hw.clk);

	state <<= __ffs(dd->idlest_mask);

	while (((__raw_readl(dd->idlest_reg) & dd->idlest_mask) != state) &&
	       i < MAX_DPLL_WAIT_TRIES) {
		i++;
		udelay(1);
	}

	if (i == MAX_DPLL_WAIT_TRIES) {
		printk(KERN_ERR "clock: %s failed transition to '%s'\n",
		       clk_name, (state) ? "locked" : "bypassed");
	} else {
		pr_debug("clock: %s transition to '%s' in %d loops\n",
			 clk_name, (state) ? "locked" : "bypassed", i);

		ret = 0;
	}

	return ret;
}

/* From 3430 TRM ES2 4.7.6.2 */
static u16 _omap3_dpll_compute_freqsel(struct clk_hw_omap *clk, u8 n)
{
	unsigned long fint;
	u16 f = 0;

	fint = __clk_get_rate(clk->dpll_data->clk_ref) / n;

	pr_debug("clock: fint is %lu\n", fint);

	if (fint >= 750000 && fint <= 1000000)
		f = 0x3;
	else if (fint > 1000000 && fint <= 1250000)
		f = 0x4;
	else if (fint > 1250000 && fint <= 1500000)
		f = 0x5;
	else if (fint > 1500000 && fint <= 1750000)
		f = 0x6;
	else if (fint > 1750000 && fint <= 2100000)
		f = 0x7;
	else if (fint > 7500000 && fint <= 10000000)
		f = 0xB;
	else if (fint > 10000000 && fint <= 12500000)
		f = 0xC;
	else if (fint > 12500000 && fint <= 15000000)
		f = 0xD;
	else if (fint > 15000000 && fint <= 17500000)
		f = 0xE;
	else if (fint > 17500000 && fint <= 21000000)
		f = 0xF;
	else
		pr_debug("clock: unknown freqsel setting for %d\n", n);

	return f;
}

/*
 * _omap3_noncore_dpll_lock - instruct a DPLL to lock and wait for readiness
 * @clk: pointer to a DPLL struct clk
 *
 * Instructs a non-CORE DPLL to lock.  Waits for the DPLL to report
 * readiness before returning.  Will save and restore the DPLL's
 * autoidle state across the enable, per the CDP code.  If the DPLL
 * locked successfully, return 0; if the DPLL did not lock in the time
 * allotted, or DPLL3 was passed in, return -EINVAL.
 */
static int _omap3_noncore_dpll_lock(struct clk_hw_omap *clk)
{
	const struct dpll_data *dd;
	u8 ai;
	u8 state = 1;
	int r = 0;

	pr_debug("clock: locking DPLL %s\n", __clk_get_name(clk->hw.clk));

	dd = clk->dpll_data;
	state <<= __ffs(dd->idlest_mask);

	/* Check if already locked */
	if ((__raw_readl(dd->idlest_reg) & dd->idlest_mask) == state)
		goto done;

	ai = omap3_dpll_autoidle_read(clk);

	if (ai)
		omap3_dpll_deny_idle(clk);

	_omap3_dpll_write_clken(clk, DPLL_LOCKED);

	r = _omap3_wait_dpll_status(clk, 1);

	if (ai)
		omap3_dpll_allow_idle(clk);

done:
	return r;
}

/*
 * _omap3_noncore_dpll_bypass - instruct a DPLL to bypass and wait for readiness
 * @clk: pointer to a DPLL struct clk
 *
 * Instructs a non-CORE DPLL to enter low-power bypass mode.  In
 * bypass mode, the DPLL's rate is set equal to its parent clock's
 * rate.  Waits for the DPLL to report readiness before returning.
 * Will save and restore the DPLL's autoidle state across the enable,
 * per the CDP code.  If the DPLL entered bypass mode successfully,
 * return 0; if the DPLL did not enter bypass in the time allotted, or
 * DPLL3 was passed in, or the DPLL does not support low-power bypass,
 * return -EINVAL.
 */
static int _omap3_noncore_dpll_bypass(struct clk_hw_omap *clk)
{
	int r;
	u8 ai;

	if (!(clk->dpll_data->modes & (1 << DPLL_LOW_POWER_BYPASS)))
		return -EINVAL;

	pr_debug("clock: configuring DPLL %s for low-power bypass\n",
		 __clk_get_name(clk->hw.clk));

	ai = omap3_dpll_autoidle_read(clk);

	_omap3_dpll_write_clken(clk, DPLL_LOW_POWER_BYPASS);

	r = _omap3_wait_dpll_status(clk, 0);

	if (ai)
		omap3_dpll_allow_idle(clk);

	return r;
}

/*
 * _omap3_noncore_dpll_stop - instruct a DPLL to stop
 * @clk: pointer to a DPLL struct clk
 *
 * Instructs a non-CORE DPLL to enter low-power stop. Will save and
 * restore the DPLL's autoidle state across the stop, per the CDP
 * code.  If DPLL3 was passed in, or the DPLL does not support
 * low-power stop, return -EINVAL; otherwise, return 0.
 */
static int _omap3_noncore_dpll_stop(struct clk_hw_omap *clk)
{
	u8 ai;

	if (!(clk->dpll_data->modes & (1 << DPLL_LOW_POWER_STOP)))
		return -EINVAL;

	pr_debug("clock: stopping DPLL %s\n", __clk_get_name(clk->hw.clk));

	ai = omap3_dpll_autoidle_read(clk);

	_omap3_dpll_write_clken(clk, DPLL_LOW_POWER_STOP);

	if (ai)
		omap3_dpll_allow_idle(clk);

	return 0;
}

/**
 * _lookup_dco - Lookup DCO used by j-type DPLL
 * @clk: pointer to a DPLL struct clk
 * @dco: digital control oscillator selector
 * @m: DPLL multiplier to set
 * @n: DPLL divider to set
 *
 * See 36xx TRM section 3.5.3.3.3.2 "Type B DPLL (Low-Jitter)"
 *
 * XXX This code is not needed for 3430/AM35xx; can it be optimized
 * out in non-multi-OMAP builds for those chips?
 */
static void _lookup_dco(struct clk_hw_omap *clk, u8 *dco, u16 m, u8 n)
{
	unsigned long fint, clkinp; /* watch out for overflow */

	clkinp = __clk_get_rate(__clk_get_parent(clk->hw.clk));
	fint = (clkinp / n) * m;

	if (fint < 1000000000)
		*dco = 2;
	else
		*dco = 4;
}

/**
 * _lookup_sddiv - Calculate sigma delta divider for j-type DPLL
 * @clk: pointer to a DPLL struct clk
 * @sd_div: target sigma-delta divider
 * @m: DPLL multiplier to set
 * @n: DPLL divider to set
 *
 * See 36xx TRM section 3.5.3.3.3.2 "Type B DPLL (Low-Jitter)"
 *
 * XXX This code is not needed for 3430/AM35xx; can it be optimized
 * out in non-multi-OMAP builds for those chips?
 */
static void _lookup_sddiv(struct clk_hw_omap *clk, u8 *sd_div, u16 m, u8 n)
{
	unsigned long clkinp, sd; /* watch out for overflow */
	int mod1, mod2;

	clkinp = __clk_get_rate(__clk_get_parent(clk->hw.clk));

	/*
	 * target sigma-delta to near 250MHz
	 * sd = ceil[(m/(n+1)) * (clkinp_MHz / 250)]
	 */
	clkinp /= 100000; /* shift from MHz to 10*Hz for 38.4 and 19.2 */
	mod1 = (clkinp * m) % (250 * n);
	sd = (clkinp * m) / (250 * n);
	mod2 = sd % 10;
	sd /= 10;

	if (mod1 || mod2)
		sd++;
	*sd_div = sd;
}

/*
 * _omap3_noncore_dpll_program - set non-core DPLL M,N values directly
 * @clk:	struct clk * of DPLL to set
 * @freqsel:	FREQSEL value to set
 *
 * Program the DPLL with the last M, N values calculated, and wait for
 * the DPLL to lock. Returns -EINVAL upon error, or 0 upon success.
 */
static int omap3_noncore_dpll_program(struct clk_hw_omap *clk, u16 freqsel)
{
	struct dpll_data *dd = clk->dpll_data;
	u8 dco, sd_div;
	u32 v;

	/* 3430 ES2 TRM: 4.7.6.9 DPLL Programming Sequence */
	_omap3_noncore_dpll_bypass(clk);

	/*
	 * Set jitter correction. No jitter correction for OMAP4 and 3630
	 * since freqsel field is no longer present
	 */
	if (!soc_is_am33xx() && !cpu_is_omap44xx() && !cpu_is_omap3630()) {
		v = __raw_readl(dd->control_reg);
		v &= ~dd->freqsel_mask;
		v |= freqsel << __ffs(dd->freqsel_mask);
		__raw_writel(v, dd->control_reg);
	}

	/* Set DPLL multiplier, divider */
	v = __raw_readl(dd->mult_div1_reg);
	v &= ~(dd->mult_mask | dd->div1_mask);
	v |= dd->last_rounded_m << __ffs(dd->mult_mask);
	v |= (dd->last_rounded_n - 1) << __ffs(dd->div1_mask);

	/* Configure dco and sd_div for dplls that have these fields */
	if (dd->dco_mask) {
		_lookup_dco(clk, &dco, dd->last_rounded_m, dd->last_rounded_n);
		v &= ~(dd->dco_mask);
		v |= dco << __ffs(dd->dco_mask);
	}
	if (dd->sddiv_mask) {
		_lookup_sddiv(clk, &sd_div, dd->last_rounded_m,
			      dd->last_rounded_n);
		v &= ~(dd->sddiv_mask);
		v |= sd_div << __ffs(dd->sddiv_mask);
	}

	__raw_writel(v, dd->mult_div1_reg);

	/* Set 4X multiplier and low-power mode */
	if (dd->m4xen_mask || dd->lpmode_mask) {
		v = __raw_readl(dd->control_reg);

		if (dd->m4xen_mask) {
			if (dd->last_rounded_m4xen)
				v |= dd->m4xen_mask;
			else
				v &= ~dd->m4xen_mask;
		}

		if (dd->lpmode_mask) {