drivers/cpufreq/exynos5440-cpufreq.c - third_party/linux - Git at Google

 /*
  * Copyright (c) 2013 Samsung Electronics Co., Ltd.
  *		http://www.samsung.com
  *
  * Amit Daniel Kachhap <amit.daniel@samsung.com>
  *
  * EXYNOS5440 - 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/clk.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/pm_opp.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>

 /* Register definitions */
 #define XMU_DVFS_CTRL		0x0060
 #define XMU_PMU_P0_7		0x0064
 #define XMU_C0_3_PSTATE		0x0090
 #define XMU_P_LIMIT		0x00a0
 #define XMU_P_STATUS		0x00a4
 #define XMU_PMUEVTEN		0x00d0
 #define XMU_PMUIRQEN		0x00d4
 #define XMU_PMUIRQ		0x00d8

 /* PMU mask and shift definations */
 #define P_VALUE_MASK		0x7

 #define XMU_DVFS_CTRL_EN_SHIFT	0

 #define P0_7_CPUCLKDEV_SHIFT	21
 #define P0_7_CPUCLKDEV_MASK	0x7
 #define P0_7_ATBCLKDEV_SHIFT	18
 #define P0_7_ATBCLKDEV_MASK	0x7
 #define P0_7_CSCLKDEV_SHIFT	15
 #define P0_7_CSCLKDEV_MASK	0x7
 #define P0_7_CPUEMA_SHIFT	28
 #define P0_7_CPUEMA_MASK	0xf
 #define P0_7_L2EMA_SHIFT	24
 #define P0_7_L2EMA_MASK		0xf
 #define P0_7_VDD_SHIFT		8
 #define P0_7_VDD_MASK		0x7f
 #define P0_7_FREQ_SHIFT		0
 #define P0_7_FREQ_MASK		0xff

 #define C0_3_PSTATE_VALID_SHIFT	8
 #define C0_3_PSTATE_CURR_SHIFT	4
 #define C0_3_PSTATE_NEW_SHIFT	0

 #define PSTATE_CHANGED_EVTEN_SHIFT	0

 #define PSTATE_CHANGED_IRQEN_SHIFT	0

 #define PSTATE_CHANGED_SHIFT		0

 /* some constant values for clock divider calculation */
 #define CPU_DIV_FREQ_MAX	500
 #define CPU_DBG_FREQ_MAX	375
 #define CPU_ATB_FREQ_MAX	500

 #define PMIC_LOW_VOLT		0x30
 #define PMIC_HIGH_VOLT		0x28

 #define CPUEMA_HIGH		0x2
 #define CPUEMA_MID		0x4
 #define CPUEMA_LOW		0x7

 #define L2EMA_HIGH		0x1
 #define L2EMA_MID		0x3
 #define L2EMA_LOW		0x4

 #define DIV_TAB_MAX	2
 /* frequency unit is 20MHZ */
 #define FREQ_UNIT	20
 #define MAX_VOLTAGE	1550000 /* In microvolt */
 #define VOLTAGE_STEP	12500	/* In microvolt */

 #define CPUFREQ_NAME		"exynos5440_dvfs"
 #define DEF_TRANS_LATENCY	100000

 enum cpufreq_level_index {
 	L0, L1, L2, L3, L4,
 	L5, L6, L7, L8, L9,
 };
 #define CPUFREQ_LEVEL_END	(L7 + 1)

 struct exynos_dvfs_data {
 	void __iomem *base;
 	struct resource *mem;
 	int irq;
 	struct clk *cpu_clk;
 	unsigned int latency;
 	struct cpufreq_frequency_table *freq_table;
 	unsigned int freq_count;
 	struct device *dev;
 	bool dvfs_enabled;
 	struct work_struct irq_work;
 };

 static struct exynos_dvfs_data *dvfs_info;
 static DEFINE_MUTEX(cpufreq_lock);
 static struct cpufreq_freqs freqs;

 static int init_div_table(void)
 {
 	struct cpufreq_frequency_table *pos, *freq_tbl = dvfs_info->freq_table;
 	unsigned int tmp, clk_div, ema_div, freq, volt_id, idx;
 	struct dev_pm_opp *opp;

 	cpufreq_for_each_entry_idx(pos, freq_tbl, idx) {
 		opp = dev_pm_opp_find_freq_exact(dvfs_info->dev,
 					pos->frequency * 1000, true);
 		if (IS_ERR(opp)) {
 			dev_err(dvfs_info->dev,
 				"failed to find valid OPP for %u KHZ\n",
 				pos->frequency);
 			return PTR_ERR(opp);
 		}

 		freq = pos->frequency / 1000; /* In MHZ */
 		clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
 					<< P0_7_CPUCLKDEV_SHIFT;
 		clk_div |= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
 					<< P0_7_ATBCLKDEV_SHIFT;
 		clk_div |= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
 					<< P0_7_CSCLKDEV_SHIFT;

 		/* Calculate EMA */
 		volt_id = dev_pm_opp_get_voltage(opp);

 		volt_id = (MAX_VOLTAGE - volt_id) / VOLTAGE_STEP;
 		if (volt_id < PMIC_HIGH_VOLT) {
 			ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
 				(L2EMA_HIGH << P0_7_L2EMA_SHIFT);
 		} else if (volt_id > PMIC_LOW_VOLT) {
 			ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) |
 				(L2EMA_LOW << P0_7_L2EMA_SHIFT);
 		} else {
 			ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) |
 				(L2EMA_MID << P0_7_L2EMA_SHIFT);
 		}

 		tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
 			| ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));

 		__raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * idx);
 		dev_pm_opp_put(opp);
 	}

 	return 0;
 }

 static void exynos_enable_dvfs(unsigned int cur_frequency)
 {
 	unsigned int tmp, cpu;
 	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
 	struct cpufreq_frequency_table *pos;
 	/* Disable DVFS */
 	__raw_writel(0,	dvfs_info->base + XMU_DVFS_CTRL);

 	/* Enable PSTATE Change Event */
 	tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
 	tmp |= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
 	__raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);

 	/* Enable PSTATE Change IRQ */
 	tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
 	tmp |= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
 	__raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);

 	/* Set initial performance index */
 	cpufreq_for_each_entry(pos, freq_table)
 		if (pos->frequency == cur_frequency)
 			break;

 	if (pos->frequency == CPUFREQ_TABLE_END) {
 		dev_crit(dvfs_info->dev, "Boot up frequency not supported\n");
 		/* Assign the highest frequency */
 		pos = freq_table;
 		cur_frequency = pos->frequency;
 	}

 	dev_info(dvfs_info->dev, "Setting dvfs initial frequency = %uKHZ",
 						cur_frequency);

 	for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
 		tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
 		tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
 		tmp |= ((pos - freq_table) << C0_3_PSTATE_NEW_SHIFT);
 		__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
 	}

 	/* Enable DVFS */
 	__raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
 				dvfs_info->base + XMU_DVFS_CTRL);
 }

 static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
 {
 	unsigned int tmp;
 	int i;
 	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;

 	mutex_lock(&cpufreq_lock);

 	freqs.old = policy->cur;
 	freqs.new = freq_table[index].frequency;

 	cpufreq_freq_transition_begin(policy, &freqs);

 	/* Set the target frequency in all C0_3_PSTATE register */
 	for_each_cpu(i, policy->cpus) {
 		tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
 		tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
 		tmp |= (index << C0_3_PSTATE_NEW_SHIFT);

 		__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
 	}
 	mutex_unlock(&cpufreq_lock);
 	return 0;
 }

 static void exynos_cpufreq_work(struct work_struct *work)
 {
 	unsigned int cur_pstate, index;
 	struct cpufreq_policy *policy = cpufreq_cpu_get(0); /* boot CPU */
 	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;

 	/* Ensure we can access cpufreq structures */
 	if (unlikely(dvfs_info->dvfs_enabled == false))
 		goto skip_work;

 	mutex_lock(&cpufreq_lock);
 	freqs.old = policy->cur;

 	cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
 	if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
 		index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
 	else
 		index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;

 	if (likely(index < dvfs_info->freq_count)) {
 		freqs.new = freq_table[index].frequency;
 	} else {
 		dev_crit(dvfs_info->dev, "New frequency out of range\n");
 		freqs.new = freqs.old;
 	}
 	cpufreq_freq_transition_end(policy, &freqs, 0);

 	cpufreq_cpu_put(policy);
 	mutex_unlock(&cpufreq_lock);
 skip_work:
 	enable_irq(dvfs_info->irq);
 }

 static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
 {
 	unsigned int tmp;

 	tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
 	if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
 		__raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
 		disable_irq_nosync(irq);
 		schedule_work(&dvfs_info->irq_work);
 	}
 	return IRQ_HANDLED;
 }

 static void exynos_sort_descend_freq_table(void)
 {
 	struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
 	int i = 0, index;
 	unsigned int tmp_freq;
 	/*
 	 * Exynos5440 clock controller state logic expects the cpufreq table to
 	 * be in descending order. But the OPP library constructs the table in
 	 * ascending order. So to make the table descending we just need to
 	 * swap the i element with the N - i element.
 	 */
 	for (i = 0; i < dvfs_info->freq_count / 2; i++) {
 		index = dvfs_info->freq_count - i - 1;
 		tmp_freq = freq_tbl[i].frequency;
 		freq_tbl[i].frequency = freq_tbl[index].frequency;
 		freq_tbl[index].frequency = tmp_freq;
 	}
 }

 static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
 	policy->clk = dvfs_info->cpu_clk;
 	return cpufreq_generic_init(policy, dvfs_info->freq_table,
 			dvfs_info->latency);
 }

 static struct cpufreq_driver exynos_driver = {
 	.flags		= CPUFREQ_STICKY | CPUFREQ_ASYNC_NOTIFICATION |
 				CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= exynos_target,
 	.get		= cpufreq_generic_get,
 	.init		= exynos_cpufreq_cpu_init,
 	.name		= CPUFREQ_NAME,
 	.attr		= cpufreq_generic_attr,
 };

 static const struct of_device_id exynos_cpufreq_match[] = {
 	{
 		.compatible = "samsung,exynos5440-cpufreq",
 	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, exynos_cpufreq_match);

 static int exynos_cpufreq_probe(struct platform_device *pdev)
 {
 	int ret = -EINVAL;
 	struct device_node *np;
 	struct resource res;
 	unsigned int cur_frequency;

 	np = pdev->dev.of_node;
 	if (!np)
 		return -ENODEV;

 	dvfs_info = devm_kzalloc(&pdev->dev, sizeof(*dvfs_info), GFP_KERNEL);
 	if (!dvfs_info) {
 		ret = -ENOMEM;
 		goto err_put_node;
 	}

 	dvfs_info->dev = &pdev->dev;

 	ret = of_address_to_resource(np, 0, &res);
 	if (ret)
 		goto err_put_node;

 	dvfs_info->base = devm_ioremap_resource(dvfs_info->dev, &res);
 	if (IS_ERR(dvfs_info->base)) {
 		ret = PTR_ERR(dvfs_info->base);
 		goto err_put_node;
 	}

 	dvfs_info->irq = irq_of_parse_and_map(np, 0);
 	if (!dvfs_info->irq) {
 		dev_err(dvfs_info->dev, "No cpufreq irq found\n");
 		ret = -ENODEV;
 		goto err_put_node;
 	}

 	ret = dev_pm_opp_of_add_table(dvfs_info->dev);
 	if (ret) {
 		dev_err(dvfs_info->dev, "failed to init OPP table: %d\n", ret);
 		goto err_put_node;
 	}

 	ret = dev_pm_opp_init_cpufreq_table(dvfs_info->dev,
 					    &dvfs_info->freq_table);
 	if (ret) {
 		dev_err(dvfs_info->dev,
 			"failed to init cpufreq table: %d\n", ret);
 		goto err_free_opp;
 	}
 	dvfs_info->freq_count = dev_pm_opp_get_opp_count(dvfs_info->dev);
 	exynos_sort_descend_freq_table();

 	if (of_property_read_u32(np, "clock-latency", &dvfs_info->latency))
 		dvfs_info->latency = DEF_TRANS_LATENCY;

 	dvfs_info->cpu_clk = devm_clk_get(dvfs_info->dev, "armclk");
 	if (IS_ERR(dvfs_info->cpu_clk)) {
 		dev_err(dvfs_info->dev, "Failed to get cpu clock\n");
 		ret = PTR_ERR(dvfs_info->cpu_clk);
 		goto err_free_table;
 	}

 	cur_frequency = clk_get_rate(dvfs_info->cpu_clk);
 	if (!cur_frequency) {
 		dev_err(dvfs_info->dev, "Failed to get clock rate\n");
 		ret = -EINVAL;
 		goto err_free_table;
 	}
 	cur_frequency /= 1000;

 	INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
 	ret = devm_request_irq(dvfs_info->dev, dvfs_info->irq,
 				exynos_cpufreq_irq, IRQF_TRIGGER_NONE,
 				CPUFREQ_NAME, dvfs_info);
 	if (ret) {
 		dev_err(dvfs_info->dev, "Failed to register IRQ\n");
 		goto err_free_table;
 	}

 	ret = init_div_table();
 	if (ret) {
 		dev_err(dvfs_info->dev, "Failed to initialise div table\n");
 		goto err_free_table;
 	}

 	exynos_enable_dvfs(cur_frequency);
 	ret = cpufreq_register_driver(&exynos_driver);
 	if (ret) {
 		dev_err(dvfs_info->dev,
 			"%s: failed to register cpufreq driver\n", __func__);
 		goto err_free_table;
 	}

 	of_node_put(np);
 	dvfs_info->dvfs_enabled = true;
 	return 0;

 err_free_table:
 	dev_pm_opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
 err_free_opp:
 	dev_pm_opp_of_remove_table(dvfs_info->dev);
 err_put_node:
 	of_node_put(np);
 	dev_err(&pdev->dev, "%s: failed initialization\n", __func__);
 	return ret;
 }

 static int exynos_cpufreq_remove(struct platform_device *pdev)
 {
 	cpufreq_unregister_driver(&exynos_driver);
 	dev_pm_opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
 	dev_pm_opp_of_remove_table(dvfs_info->dev);
 	return 0;
 }

 static struct platform_driver exynos_cpufreq_platdrv = {
 	.driver = {
 		.name	= "exynos5440-cpufreq",
 		.of_match_table = exynos_cpufreq_match,
 	},
 	.probe		= exynos_cpufreq_probe,
 	.remove		= exynos_cpufreq_remove,
 };
 module_platform_driver(exynos_cpufreq_platdrv);

 MODULE_AUTHOR("Amit Daniel Kachhap <amit.daniel@samsung.com>");
 MODULE_DESCRIPTION("Exynos5440 cpufreq driver");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (c) 2013 Samsung Electronics Co., Ltd.
	* http://www.samsung.com
	*
	* Amit Daniel Kachhap <amit.daniel@samsung.com>
	*
	* EXYNOS5440 - 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/clk.h>
	#include <linux/cpu.h>
	#include <linux/cpufreq.h>
	#include <linux/err.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/pm_opp.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>

	/* Register definitions */
	#define XMU_DVFS_CTRL 0x0060
	#define XMU_PMU_P0_7 0x0064
	#define XMU_C0_3_PSTATE 0x0090
	#define XMU_P_LIMIT 0x00a0
	#define XMU_P_STATUS 0x00a4
	#define XMU_PMUEVTEN 0x00d0
	#define XMU_PMUIRQEN 0x00d4
	#define XMU_PMUIRQ 0x00d8

	/* PMU mask and shift definations */
	#define P_VALUE_MASK 0x7

	#define XMU_DVFS_CTRL_EN_SHIFT 0

	#define P0_7_CPUCLKDEV_SHIFT 21
	#define P0_7_CPUCLKDEV_MASK 0x7
	#define P0_7_ATBCLKDEV_SHIFT 18
	#define P0_7_ATBCLKDEV_MASK 0x7
	#define P0_7_CSCLKDEV_SHIFT 15
	#define P0_7_CSCLKDEV_MASK 0x7
	#define P0_7_CPUEMA_SHIFT 28
	#define P0_7_CPUEMA_MASK 0xf
	#define P0_7_L2EMA_SHIFT 24
	#define P0_7_L2EMA_MASK 0xf
	#define P0_7_VDD_SHIFT 8
	#define P0_7_VDD_MASK 0x7f
	#define P0_7_FREQ_SHIFT 0
	#define P0_7_FREQ_MASK 0xff

	#define C0_3_PSTATE_VALID_SHIFT 8
	#define C0_3_PSTATE_CURR_SHIFT 4
	#define C0_3_PSTATE_NEW_SHIFT 0

	#define PSTATE_CHANGED_EVTEN_SHIFT 0

	#define PSTATE_CHANGED_IRQEN_SHIFT 0

	#define PSTATE_CHANGED_SHIFT 0

	/* some constant values for clock divider calculation */
	#define CPU_DIV_FREQ_MAX 500
	#define CPU_DBG_FREQ_MAX 375
	#define CPU_ATB_FREQ_MAX 500

	#define PMIC_LOW_VOLT 0x30
	#define PMIC_HIGH_VOLT 0x28

	#define CPUEMA_HIGH 0x2
	#define CPUEMA_MID 0x4
	#define CPUEMA_LOW 0x7

	#define L2EMA_HIGH 0x1
	#define L2EMA_MID 0x3
	#define L2EMA_LOW 0x4

	#define DIV_TAB_MAX 2
	/* frequency unit is 20MHZ */
	#define FREQ_UNIT 20
	#define MAX_VOLTAGE 1550000 /* In microvolt */
	#define VOLTAGE_STEP 12500 /* In microvolt */

	#define CPUFREQ_NAME "exynos5440_dvfs"
	#define DEF_TRANS_LATENCY 100000

	enum cpufreq_level_index {
	L0, L1, L2, L3, L4,
	L5, L6, L7, L8, L9,
	};
	#define CPUFREQ_LEVEL_END (L7 + 1)

	struct exynos_dvfs_data {
	void __iomem *base;
	struct resource *mem;
	int irq;
	struct clk *cpu_clk;
	unsigned int latency;
	struct cpufreq_frequency_table *freq_table;
	unsigned int freq_count;
	struct device *dev;
	bool dvfs_enabled;
	struct work_struct irq_work;
	};

	static struct exynos_dvfs_data *dvfs_info;
	static DEFINE_MUTEX(cpufreq_lock);
	static struct cpufreq_freqs freqs;

	static int init_div_table(void)
	{
	struct cpufreq_frequency_table pos, freq_tbl = dvfs_info->freq_table;
	unsigned int tmp, clk_div, ema_div, freq, volt_id, idx;
	struct dev_pm_opp *opp;

	cpufreq_for_each_entry_idx(pos, freq_tbl, idx) {
	opp = dev_pm_opp_find_freq_exact(dvfs_info->dev,
	pos->frequency * 1000, true);
	if (IS_ERR(opp)) {
	dev_err(dvfs_info->dev,
	"failed to find valid OPP for %u KHZ\n",
	pos->frequency);
	return PTR_ERR(opp);
	}

	freq = pos->frequency / 1000; /* In MHZ */
	clk_div = ((freq / CPU_DIV_FREQ_MAX) & P0_7_CPUCLKDEV_MASK)
	<< P0_7_CPUCLKDEV_SHIFT;
	clk_div \|= ((freq / CPU_ATB_FREQ_MAX) & P0_7_ATBCLKDEV_MASK)
	<< P0_7_ATBCLKDEV_SHIFT;
	clk_div \|= ((freq / CPU_DBG_FREQ_MAX) & P0_7_CSCLKDEV_MASK)
	<< P0_7_CSCLKDEV_SHIFT;

	/* Calculate EMA */
	volt_id = dev_pm_opp_get_voltage(opp);

	volt_id = (MAX_VOLTAGE - volt_id) / VOLTAGE_STEP;
	if (volt_id < PMIC_HIGH_VOLT) {
	ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) \|
	(L2EMA_HIGH << P0_7_L2EMA_SHIFT);
	} else if (volt_id > PMIC_LOW_VOLT) {
	ema_div = (CPUEMA_LOW << P0_7_CPUEMA_SHIFT) \|
	(L2EMA_LOW << P0_7_L2EMA_SHIFT);
	} else {
	ema_div = (CPUEMA_MID << P0_7_CPUEMA_SHIFT) \|
	(L2EMA_MID << P0_7_L2EMA_SHIFT);
	}

	tmp = (clk_div \| ema_div \| (volt_id << P0_7_VDD_SHIFT)
	\| ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));

	__raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * idx);
	dev_pm_opp_put(opp);
	}

	return 0;
	}

	static void exynos_enable_dvfs(unsigned int cur_frequency)
	{
	unsigned int tmp, cpu;
	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;
	struct cpufreq_frequency_table *pos;
	/* Disable DVFS */
	__raw_writel(0, dvfs_info->base + XMU_DVFS_CTRL);

	/* Enable PSTATE Change Event */
	tmp = __raw_readl(dvfs_info->base + XMU_PMUEVTEN);
	tmp \|= (1 << PSTATE_CHANGED_EVTEN_SHIFT);
	__raw_writel(tmp, dvfs_info->base + XMU_PMUEVTEN);

	/* Enable PSTATE Change IRQ */
	tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQEN);
	tmp \|= (1 << PSTATE_CHANGED_IRQEN_SHIFT);
	__raw_writel(tmp, dvfs_info->base + XMU_PMUIRQEN);

	/* Set initial performance index */
	cpufreq_for_each_entry(pos, freq_table)
	if (pos->frequency == cur_frequency)
	break;

	if (pos->frequency == CPUFREQ_TABLE_END) {
	dev_crit(dvfs_info->dev, "Boot up frequency not supported\n");
	/* Assign the highest frequency */
	pos = freq_table;
	cur_frequency = pos->frequency;
	}

	dev_info(dvfs_info->dev, "Setting dvfs initial frequency = %uKHZ",
	cur_frequency);

	for (cpu = 0; cpu < CONFIG_NR_CPUS; cpu++) {
	tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
	tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
	tmp \|= ((pos - freq_table) << C0_3_PSTATE_NEW_SHIFT);
	__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + cpu * 4);
	}

	/* Enable DVFS */
	__raw_writel(1 << XMU_DVFS_CTRL_EN_SHIFT,
	dvfs_info->base + XMU_DVFS_CTRL);
	}

	static int exynos_target(struct cpufreq_policy *policy, unsigned int index)
	{
	unsigned int tmp;
	int i;
	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;

	mutex_lock(&cpufreq_lock);

	freqs.old = policy->cur;
	freqs.new = freq_table[index].frequency;

	cpufreq_freq_transition_begin(policy, &freqs);

	/* Set the target frequency in all C0_3_PSTATE register */
	for_each_cpu(i, policy->cpus) {
	tmp = __raw_readl(dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
	tmp &= ~(P_VALUE_MASK << C0_3_PSTATE_NEW_SHIFT);
	tmp \|= (index << C0_3_PSTATE_NEW_SHIFT);

	__raw_writel(tmp, dvfs_info->base + XMU_C0_3_PSTATE + i * 4);
	}
	mutex_unlock(&cpufreq_lock);
	return 0;
	}

	static void exynos_cpufreq_work(struct work_struct *work)
	{
	unsigned int cur_pstate, index;
	struct cpufreq_policy policy = cpufreq_cpu_get(0); / boot CPU */
	struct cpufreq_frequency_table *freq_table = dvfs_info->freq_table;

	/* Ensure we can access cpufreq structures */
	if (unlikely(dvfs_info->dvfs_enabled == false))
	goto skip_work;

	mutex_lock(&cpufreq_lock);
	freqs.old = policy->cur;

	cur_pstate = __raw_readl(dvfs_info->base + XMU_P_STATUS);
	if (cur_pstate >> C0_3_PSTATE_VALID_SHIFT & 0x1)
	index = (cur_pstate >> C0_3_PSTATE_CURR_SHIFT) & P_VALUE_MASK;
	else
	index = (cur_pstate >> C0_3_PSTATE_NEW_SHIFT) & P_VALUE_MASK;

	if (likely(index < dvfs_info->freq_count)) {
	freqs.new = freq_table[index].frequency;
	} else {
	dev_crit(dvfs_info->dev, "New frequency out of range\n");
	freqs.new = freqs.old;
	}
	cpufreq_freq_transition_end(policy, &freqs, 0);

	cpufreq_cpu_put(policy);
	mutex_unlock(&cpufreq_lock);
	skip_work:
	enable_irq(dvfs_info->irq);
	}

	static irqreturn_t exynos_cpufreq_irq(int irq, void *id)
	{
	unsigned int tmp;

	tmp = __raw_readl(dvfs_info->base + XMU_PMUIRQ);
	if (tmp >> PSTATE_CHANGED_SHIFT & 0x1) {
	__raw_writel(tmp, dvfs_info->base + XMU_PMUIRQ);
	disable_irq_nosync(irq);
	schedule_work(&dvfs_info->irq_work);
	}
	return IRQ_HANDLED;
	}

	static void exynos_sort_descend_freq_table(void)
	{
	struct cpufreq_frequency_table *freq_tbl = dvfs_info->freq_table;
	int i = 0, index;
	unsigned int tmp_freq;
	/*
	* Exynos5440 clock controller state logic expects the cpufreq table to
	* be in descending order. But the OPP library constructs the table in
	* ascending order. So to make the table descending we just need to
	* swap the i element with the N - i element.
	*/
	for (i = 0; i < dvfs_info->freq_count / 2; i++) {
	index = dvfs_info->freq_count - i - 1;
	tmp_freq = freq_tbl[i].frequency;
	freq_tbl[i].frequency = freq_tbl[index].frequency;
	freq_tbl[index].frequency = tmp_freq;
	}
	}

	static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
	{
	policy->clk = dvfs_info->cpu_clk;
	return cpufreq_generic_init(policy, dvfs_info->freq_table,
	dvfs_info->latency);
	}

	static struct cpufreq_driver exynos_driver = {
	.flags = CPUFREQ_STICKY \| CPUFREQ_ASYNC_NOTIFICATION \|
	CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	.verify = cpufreq_generic_frequency_table_verify,
	.target_index = exynos_target,
	.get = cpufreq_generic_get,
	.init = exynos_cpufreq_cpu_init,
	.name = CPUFREQ_NAME,
	.attr = cpufreq_generic_attr,
	};

	static const struct of_device_id exynos_cpufreq_match[] = {
	{
	.compatible = "samsung,exynos5440-cpufreq",
	},
	{},
	};
	MODULE_DEVICE_TABLE(of, exynos_cpufreq_match);

	static int exynos_cpufreq_probe(struct platform_device *pdev)
	{
	int ret = -EINVAL;
	struct device_node *np;
	struct resource res;
	unsigned int cur_frequency;

	np = pdev->dev.of_node;
	if (!np)
	return -ENODEV;

	dvfs_info = devm_kzalloc(&pdev->dev, sizeof(*dvfs_info), GFP_KERNEL);
	if (!dvfs_info) {
	ret = -ENOMEM;
	goto err_put_node;
	}

	dvfs_info->dev = &pdev->dev;

	ret = of_address_to_resource(np, 0, &res);
	if (ret)
	goto err_put_node;

	dvfs_info->base = devm_ioremap_resource(dvfs_info->dev, &res);
	if (IS_ERR(dvfs_info->base)) {
	ret = PTR_ERR(dvfs_info->base);
	goto err_put_node;
	}

	dvfs_info->irq = irq_of_parse_and_map(np, 0);
	if (!dvfs_info->irq) {
	dev_err(dvfs_info->dev, "No cpufreq irq found\n");
	ret = -ENODEV;
	goto err_put_node;
	}

	ret = dev_pm_opp_of_add_table(dvfs_info->dev);
	if (ret) {
	dev_err(dvfs_info->dev, "failed to init OPP table: %d\n", ret);
	goto err_put_node;
	}

	ret = dev_pm_opp_init_cpufreq_table(dvfs_info->dev,
	&dvfs_info->freq_table);
	if (ret) {
	dev_err(dvfs_info->dev,
	"failed to init cpufreq table: %d\n", ret);
	goto err_free_opp;
	}
	dvfs_info->freq_count = dev_pm_opp_get_opp_count(dvfs_info->dev);
	exynos_sort_descend_freq_table();

	if (of_property_read_u32(np, "clock-latency", &dvfs_info->latency))
	dvfs_info->latency = DEF_TRANS_LATENCY;

	dvfs_info->cpu_clk = devm_clk_get(dvfs_info->dev, "armclk");
	if (IS_ERR(dvfs_info->cpu_clk)) {
	dev_err(dvfs_info->dev, "Failed to get cpu clock\n");
	ret = PTR_ERR(dvfs_info->cpu_clk);
	goto err_free_table;
	}

	cur_frequency = clk_get_rate(dvfs_info->cpu_clk);
	if (!cur_frequency) {
	dev_err(dvfs_info->dev, "Failed to get clock rate\n");
	ret = -EINVAL;
	goto err_free_table;
	}
	cur_frequency /= 1000;

	INIT_WORK(&dvfs_info->irq_work, exynos_cpufreq_work);
	ret = devm_request_irq(dvfs_info->dev, dvfs_info->irq,
	exynos_cpufreq_irq, IRQF_TRIGGER_NONE,
	CPUFREQ_NAME, dvfs_info);
	if (ret) {
	dev_err(dvfs_info->dev, "Failed to register IRQ\n");
	goto err_free_table;
	}

	ret = init_div_table();
	if (ret) {
	dev_err(dvfs_info->dev, "Failed to initialise div table\n");
	goto err_free_table;
	}

	exynos_enable_dvfs(cur_frequency);
	ret = cpufreq_register_driver(&exynos_driver);
	if (ret) {
	dev_err(dvfs_info->dev,
	"%s: failed to register cpufreq driver\n", __func__);
	goto err_free_table;
	}

	of_node_put(np);
	dvfs_info->dvfs_enabled = true;
	return 0;

	err_free_table:
	dev_pm_opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
	err_free_opp:
	dev_pm_opp_of_remove_table(dvfs_info->dev);
	err_put_node:
	of_node_put(np);
	dev_err(&pdev->dev, "%s: failed initialization\n", __func__);
	return ret;
	}

	static int exynos_cpufreq_remove(struct platform_device *pdev)
	{
	cpufreq_unregister_driver(&exynos_driver);
	dev_pm_opp_free_cpufreq_table(dvfs_info->dev, &dvfs_info->freq_table);
	dev_pm_opp_of_remove_table(dvfs_info->dev);
	return 0;
	}

	static struct platform_driver exynos_cpufreq_platdrv = {
	.driver = {
	.name = "exynos5440-cpufreq",
	.of_match_table = exynos_cpufreq_match,
	},
	.probe = exynos_cpufreq_probe,
	.remove = exynos_cpufreq_remove,
	};
	module_platform_driver(exynos_cpufreq_platdrv);

	MODULE_AUTHOR("Amit Daniel Kachhap <amit.daniel@samsung.com>");
	MODULE_DESCRIPTION("Exynos5440 cpufreq driver");
	MODULE_LICENSE("GPL");