/*
 * Copyright (c) 2010-2012 Samsung Electronics Co., Ltd.
 *		http://www.samsung.com
 *
 * EXYNOS4X12 - CPU frequency scaling support
 *
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/cpufreq.h>

#include <mach/regs-clock.h>

#include "exynos-cpufreq.h"

static struct clk *cpu_clk;
static struct clk *mout_core;
static struct clk *sclk_mpll;
static struct clk *mout_apll;

static unsigned int exynos4x12_volt_table[] = {
	1350000, 1287500, 1250000, 1187500, 1137500, 1087500, 1037500,
	1000000,  987500,  975000,  950000,  925000,  900000,  900000
};

static struct cpufreq_frequency_table exynos4x12_freq_table[] = {
	{L0, CPUFREQ_ENTRY_INVALID},
	{L1, 1400 * 1000},
	{L2, 1300 * 1000},
	{L3, 1200 * 1000},
	{L4, 1100 * 1000},
	{L5, 1000 * 1000},
	{L6,  900 * 1000},
	{L7,  800 * 1000},
	{L8,  700 * 1000},
	{L9,  600 * 1000},
	{L10, 500 * 1000},
	{L11, 400 * 1000},
	{L12, 300 * 1000},
	{L13, 200 * 1000},
	{0, CPUFREQ_TABLE_END},
};

static struct apll_freq *apll_freq_4x12;

static struct apll_freq apll_freq_4212[] = {
	/*
	 * values:
	 * freq
	 * clock divider for CORE, COREM0, COREM1, PERIPH, ATB, PCLK_DBG, APLL, CORE2
	 * clock divider for COPY, HPM, RESERVED
	 * PLL M, P, S
	 */
	APLL_FREQ(1500, 0, 3, 7, 0, 6, 1, 2, 0, 6, 2, 0, 250, 4, 0),
	APLL_FREQ(1400, 0, 3, 7, 0, 6, 1, 2, 0, 6, 2, 0, 175, 3, 0),
	APLL_FREQ(1300, 0, 3, 7, 0, 5, 1, 2, 0, 5, 2, 0, 325, 6, 0),
	APLL_FREQ(1200, 0, 3, 7, 0, 5, 1, 2, 0, 5, 2, 0, 200, 4, 0),
	APLL_FREQ(1100, 0, 3, 6, 0, 4, 1, 2, 0, 4, 2, 0, 275, 6, 0),
	APLL_FREQ(1000, 0, 2, 5, 0, 4, 1, 1, 0, 4, 2, 0, 125, 3, 0),
	APLL_FREQ(900,  0, 2, 5, 0, 3, 1, 1, 0, 3, 2, 0, 150, 4, 0),
	APLL_FREQ(800,  0, 2, 5, 0, 3, 1, 1, 0, 3, 2, 0, 100, 3, 0),
	APLL_FREQ(700,  0, 2, 4, 0, 3, 1, 1, 0, 3, 2, 0, 175, 3, 1),
	APLL_FREQ(600,  0, 2, 4, 0, 3, 1, 1, 0, 3, 2, 0, 200, 4, 1),
	APLL_FREQ(500,  0, 2, 4, 0, 3, 1, 1, 0, 3, 2, 0, 125, 3, 1),
	APLL_FREQ(400,  0, 2, 4, 0, 3, 1, 1, 0, 3, 2, 0, 100, 3, 1),
	APLL_FREQ(300,  0, 2, 4, 0, 2, 1, 1, 0, 3, 2, 0, 200, 4, 2),
	APLL_FREQ(200,  0, 1, 3, 0, 1, 1, 1, 0, 3, 2, 0, 100, 3, 2),
};

static struct apll_freq apll_freq_4412[] = {
	/*
	 * values:
	 * freq
	 * clock divider for CORE, COREM0, COREM1, PERIPH, ATB, PCLK_DBG, APLL, CORE2
	 * clock divider for COPY, HPM, CORES
	 * PLL M, P, S
	 */
	APLL_FREQ(1500, 0, 3, 7, 0, 6, 1, 2, 0, 6, 0, 7, 250, 4, 0),
	APLL_FREQ(1400, 0, 3, 7, 0, 6, 1, 2, 0, 6, 0, 6, 175, 3, 0),
	APLL_FREQ(1300, 0, 3, 7, 0, 5, 1, 2, 0, 5, 0, 6, 325, 6, 0),
	APLL_FREQ(1200, 0, 3, 7, 0, 5, 1, 2, 0, 5, 0, 5, 200, 4, 0),
	APLL_FREQ(1100, 0, 3, 6, 0, 4, 1, 2, 0, 4, 0, 5, 275, 6, 0),
	APLL_FREQ(1000, 0, 2, 5, 0, 4, 1, 1, 0, 4, 0, 4, 125, 3, 0),
	APLL_FREQ(900,  0, 2, 5, 0, 3, 1, 1, 0, 3, 0, 4, 150, 4, 0),
	APLL_FREQ(800,  0, 2, 5, 0, 3, 1, 1, 0, 3, 0, 3, 100, 3, 0),
	APLL_FREQ(700,  0, 2, 4, 0, 3, 1, 1, 0, 3, 0, 3, 175, 3, 1),
	APLL_FREQ(600,  0, 2, 4, 0, 3, 1, 1, 0, 3, 0, 2, 200, 4, 1),
	APLL_FREQ(500,  0, 2, 4, 0, 3, 1, 1, 0, 3, 0, 2, 125, 3, 1),
	APLL_FREQ(400,  0, 2, 4, 0, 3, 1, 1, 0, 3, 0, 1, 100, 3, 1),
	APLL_FREQ(300,  0, 2, 4, 0, 2, 1, 1, 0, 3, 0, 1, 200, 4, 2),
	APLL_FREQ(200,  0, 1, 3, 0, 1, 1, 1, 0, 3, 0, 0, 100, 3, 2),
};

static void exynos4x12_set_clkdiv(unsigned int div_index)
{
	unsigned int tmp;
	unsigned int stat_cpu1;

	/* Change Divider - CPU0 */

	tmp = apll_freq_4x12[div_index].clk_div_cpu0;

	__raw_writel(tmp, EXYNOS4_CLKDIV_CPU);

	while (__raw_readl(EXYNOS4_CLKDIV_STATCPU) & 0x11111111)
		cpu_relax();

	/* Change Divider - CPU1 */
	tmp = apll_freq_4x12[div_index].clk_div_cpu1;

	__raw_writel(tmp, EXYNOS4_CLKDIV_CPU1);
	if (soc_is_exynos4212())
		stat_cpu1 = 0x11;
	else
		stat_cpu1 = 0x111;

	while (__raw_readl(EXYNOS4_CLKDIV_STATCPU1) & stat_cpu1)
		cpu_relax();
}

static void exynos4x12_set_apll(unsigned int index)
{
	unsigned int tmp, freq = apll_freq_4x12[index].freq * 1000;
	struct clk *clk;

	clk = clk_get_parent(mout_apll);

	/* MUX_CORE_SEL = MPLL, ARMCLK uses MPLL for lock time */
	clk_set_parent(mout_core, sclk_mpll);
	do {
		cpu_relax();
		tmp = (__raw_readl(EXYNOS4_CLKMUX_STATCPU)
			>> EXYNOS4_CLKSRC_CPU_MUXCORE_SHIFT);
		tmp &= 0x7;
	} while (tmp != 0x2);

	clk_set_rate(clk, freq);

	/* MUX_CORE_SEL = APLL */
	clk_set_parent(mout_core, mout_apll);
	do {
		cpu_relax();
		tmp = __raw_readl(EXYNOS4_CLKMUX_STATCPU);
		tmp &= EXYNOS4_CLKMUX_STATCPU_MUXCORE_MASK;
	} while (tmp != (0x1 << EXYNOS4_CLKSRC_CPU_MUXCORE_SHIFT));
}

static bool exynos4x12_pms_change(unsigned int old_index, unsigned int new_index)
{
	unsigned int old_pm = apll_freq_4x12[old_index].mps >> 8;
	unsigned int new_pm = apll_freq_4x12[new_index].mps >> 8;

	return (old_pm == new_pm) ? 0 : 1;
}

static void exynos4x12_set_frequency(unsigned int old_index,
				  unsigned int new_index)
{
	unsigned int tmp;

	if (old_index > new_index) {
		if (!exynos4x12_pms_change(old_index, new_index)) {
			/* 1. Change the system clock divider values */
			exynos4x12_set_clkdiv(new_index);
			/* 2. Change just s value in apll m,p,s value */
			tmp = __raw_readl(EXYNOS4_APLL_CON0);
			tmp &= ~(0x7 << 0);
			tmp |= apll_freq_4x12[new_index].mps & 0x7;
			__raw_writel(tmp, EXYNOS4_APLL_CON0);

		} else {
			/* Clock Configuration Procedure */
			/* 1. Change the system clock divider values */
			exynos4x12_set_clkdiv(new_index);
			/* 2. Change the apll m,p,s value */
			exynos4x12_set_apll(new_index);
		}
	} else if (old_index < new_index) {
		if (!exynos4x12_pms_change(old_index, new_index)) {
			/* 1. Change just s value in apll m,p,s value */
			tmp = __raw_readl(EXYNOS4_APLL_CON0);
			tmp &= ~(0x7 << 0);
			tmp |= apll_freq_4x12[new_index].mps & 0x7;
			__raw_writel(tmp, EXYNOS4_APLL_CON0);
			/* 2. Change the system clock divider values */
			exynos4x12_set_clkdiv(new_index);
		} else {
			/* Clock Configuration Procedure */
			/* 1. Change the apll m,p,s value */
			exynos4x12_set_apll(new_index);
			/* 2. Change the system clock divider values */
			exynos4x12_set_clkdiv(new_index);
		}
	}
}

int exynos4x12_cpufreq_init(struct exynos_dvfs_info *info)
{
	unsigned long rate;
	cpu_clk = clk_get(info->dev, "arm_clk");
	if (IS_ERR(cpu_clk))
		return PTR_ERR(cpu_clk);

	mout_core = clk_get(info->dev, "mout_core");
	if (IS_ERR(mout_core))
		goto err_moutcore;

	sclk_mpll = clk_get(info->dev, "mout_mpll_user_c");
	if (IS_ERR(sclk_mpll))
		goto err_sclk_mpll;

	rate = clk_get_rate(sclk_mpll) / 1000;

	mout_apll = clk_get(info->dev, "mout_apll");
	if (IS_ERR(mout_apll))
		goto err_mout_apll;

	if (soc_is_exynos4212())
		apll_freq_4x12 = apll_freq_4212;
	else
		apll_freq_4x12 = apll_freq_4412;

	info->mpll_freq_khz = rate;
	/* 800Mhz */
	info->pll_safe_idx = L7;
	info->cpu_clk = cpu_clk;
	info->volt_table = exynos4x12_volt_table;

	info->freq_table = exynos_of_parse_freq_table(info, "freq_table");
	if (!info->freq_table)
		info->freq_table = exynos4x12_freq_table;

	info->set_freq = exynos4x12_set_frequency;
	info->need_apll_change = exynos4x12_pms_change;

	return 0;

err_mout_apll:
	clk_put(sclk_mpll);
err_sclk_mpll:
	clk_put(mout_core);
err_moutcore:
	clk_put(cpu_clk);

	pr_debug("%s: failed initialization\n", __func__);
	return -EINVAL;
}
EXPORT_SYMBOL(exynos4x12_cpufreq_init);