diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 8f04910..464fa21 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -65,4 +65,17 @@
 
 comment "DEVFREQ Drivers"
 
+config ARM_EXYNOS4_BUS_DEVFREQ
+	bool "ARM Exynos4210/4212/4412 Memory Bus DEVFREQ Driver"
+	depends on CPU_EXYNOS4210 || CPU_EXYNOS4212 || CPU_EXYNOS4412
+	select ARCH_HAS_OPP
+	select DEVFREQ_GOV_SIMPLE_ONDEMAND
+	help
+	  This adds the DEVFREQ driver for Exynos4210 memory bus (vdd_int)
+	  and Exynos4212/4412 memory interface and bus (vdd_mif + vdd_int).
+	  It reads PPMU counters of memory controllers and adjusts
+	  the operating frequencies and voltages with OPP support.
+	  To operate with optimal voltages, ASV support is required
+	  (CONFIG_EXYNOS_ASV).
+
 endif # PM_DEVFREQ
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 4564a89..8c46423 100644
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -3,3 +3,6 @@
 obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE)	+= governor_performance.o
 obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
 obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
+
+# DEVFREQ Drivers
+obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos4_bus.o
diff --git a/drivers/devfreq/exynos4_bus.c b/drivers/devfreq/exynos4_bus.c
new file mode 100644
index 0000000..6460577
--- /dev/null
+++ b/drivers/devfreq/exynos4_bus.c
@@ -0,0 +1,1135 @@
+/* drivers/devfreq/exynos4210_memorybus.c
+ *
+ * Copyright (c) 2011 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com/
+ *	MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * EXYNOS4 - Memory/Bus clock frequency scaling support in DEVFREQ framework
+ *	This version supports EXYNOS4210 only. This changes bus frequencies
+ *	and vddint voltages. Exynos4412/4212 should be able to be supported
+ *	with minor modifications.
+ *
+ * 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/io.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/suspend.h>
+#include <linux/opp.h>
+#include <linux/devfreq.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/module.h>
+
+/* Exynos4 ASV has been in the mailing list, but not upstreamed, yet. */
+#ifdef CONFIG_EXYNOS_ASV
+extern unsigned int exynos_result_of_asv;
+#endif
+
+#include <mach/regs-clock.h>
+
+#include <plat/map-s5p.h>
+
+#define MAX_SAFEVOLT	1200000 /* 1.2V */
+
+enum exynos4_busf_type {
+	TYPE_BUSF_EXYNOS4210,
+	TYPE_BUSF_EXYNOS4x12,
+};
+
+/* Assume that the bus is saturated if the utilization is 40% */
+#define BUS_SATURATION_RATIO	40
+
+enum ppmu_counter {
+	PPMU_PMNCNT0 = 0,
+	PPMU_PMCCNT1,
+	PPMU_PMNCNT2,
+	PPMU_PMNCNT3,
+	PPMU_PMNCNT_MAX,
+};
+struct exynos4_ppmu {
+	void __iomem *hw_base;
+	unsigned int ccnt;
+	unsigned int event;
+	unsigned int count[PPMU_PMNCNT_MAX];
+	bool ccnt_overflow;
+	bool count_overflow[PPMU_PMNCNT_MAX];
+};
+
+enum busclk_level_idx {
+	LV_0 = 0,
+	LV_1,
+	LV_2,
+	LV_3,
+	LV_4,
+	_LV_END
+};
+#define EX4210_LV_MAX	LV_2
+#define EX4x12_LV_MAX	LV_4
+#define EX4210_LV_NUM	(LV_2 + 1)
+#define EX4x12_LV_NUM	(LV_4 + 1)
+
+struct busfreq_data {
+	enum exynos4_busf_type type;
+	struct device *dev;
+	struct devfreq *devfreq;
+	bool disabled;
+	struct regulator *vdd_int;
+	struct regulator *vdd_mif; /* Exynos4412/4212 only */
+	struct opp *curr_opp;
+	struct exynos4_ppmu dmc[2];
+
+	struct notifier_block pm_notifier;
+	struct mutex lock;
+
+	/* Dividers calculated at boot/probe-time */
+	unsigned int dmc_divtable[_LV_END]; /* DMC0 */
+	unsigned int top_divtable[_LV_END];
+};
+
+struct bus_opp_table {
+	unsigned int idx;
+	unsigned long clk;
+	unsigned long volt;
+};
+
+/* 4210 controls clock of mif and voltage of int */
+static struct bus_opp_table exynos4210_busclk_table[] = {
+	{LV_0, 400000, 1150000},
+	{LV_1, 267000, 1050000},
+	{LV_2, 133000, 1025000},
+	{0, 0, 0},
+};
+
+/*
+ * MIF is the main control knob clock for exynox4x12 MIF/INT
+ * clock and voltage of both mif/int are controlled.
+ */
+static struct bus_opp_table exynos4x12_mifclk_table[] = {
+	{LV_0, 400000, 1100000},
+	{LV_1, 267000, 1000000},
+	{LV_2, 160000, 950000},
+	{LV_3, 133000, 950000},
+	{LV_4, 100000, 950000},
+	{0, 0, 0},
+};
+
+/*
+ * INT is not the control knob of 4x12. LV_x is not meant to represent
+ * the current performance. (MIF does)
+ */
+static struct bus_opp_table exynos4x12_intclk_table[] = {
+	{LV_0, 200000, 1000000},
+	{LV_1, 160000, 950000},
+	{LV_2, 133000, 925000},
+	{LV_3, 100000, 900000},
+	{0, 0, 0},
+};
+
+/* TODO: asv volt definitions are "__initdata"? */
+/* Some chips have different operating voltages */
+static unsigned int exynos4210_asv_volt[][EX4210_LV_NUM] = {
+	{1150000, 1050000, 1050000},
+	{1125000, 1025000, 1025000},
+	{1100000, 1000000, 1000000},
+	{1075000, 975000, 975000},
+	{1050000, 950000, 950000},
+};
+
+static unsigned int exynos4x12_mif_step_50[][EX4x12_LV_NUM] = {
+	/* 400      267     160     133     100 */
+	{1050000, 950000, 900000, 900000, 900000}, /* ASV0 */
+	{1050000, 950000, 900000, 900000, 900000}, /* ASV1 */
+	{1050000, 950000, 900000, 900000, 900000}, /* ASV2 */
+	{1050000, 900000, 900000, 900000, 900000}, /* ASV3 */
+	{1050000, 900000, 900000, 900000, 850000}, /* ASV4 */
+	{1050000, 900000, 900000, 850000, 850000}, /* ASV5 */
+	{1050000, 900000, 850000, 850000, 850000}, /* ASV6 */
+	{1050000, 900000, 850000, 850000, 850000}, /* ASV7 */
+	{1050000, 900000, 850000, 850000, 850000}, /* ASV8 */
+};
+
+static unsigned int exynos4x12_int_volt[][EX4x12_LV_NUM] = {
+	/* 200    160      133     100 */
+	{1000000, 950000, 925000, 900000}, /* ASV0 */
+	{975000,  925000, 925000, 900000}, /* ASV1 */
+	{950000,  925000, 900000, 875000}, /* ASV2 */
+	{950000,  900000, 900000, 875000}, /* ASV3 */
+	{925000,  875000, 875000, 875000}, /* ASV4 */
+	{900000,  850000, 850000, 850000}, /* ASV5 */
+	{900000,  850000, 850000, 850000}, /* ASV6 */
+	{900000,  850000, 850000, 850000}, /* ASV7 */
+	{900000,  850000, 850000, 850000}, /* ASV8 */
+};
+
+/*** Clock Divider Data for Exynos4210 ***/
+static unsigned int exynos4210_clkdiv_dmc0[][8] = {
+	/*
+	 * Clock divider value for following
+	 * { DIVACP, DIVACP_PCLK, DIVDPHY, DIVDMC, DIVDMCD
+	 *		DIVDMCP, DIVCOPY2, DIVCORE_TIMERS }
+	 */
+
+	/* DMC L0: 400MHz */
+	{ 3, 1, 1, 1, 1, 1, 3, 1 },
+	/* DMC L1: 266.7MHz */
+	{ 4, 1, 1, 2, 1, 1, 3, 1 },
+	/* DMC L2: 133MHz */
+	{ 5, 1, 1, 5, 1, 1, 3, 1 },
+};
+static unsigned int exynos4210_clkdiv_top[][5] = {
+	/*
+	 * Clock divider value for following
+	 * { DIVACLK200, DIVACLK100, DIVACLK160, DIVACLK133, DIVONENAND }
+	 */
+	/* ACLK200 L0: 200MHz */
+	{ 3, 7, 4, 5, 1 },
+	/* ACLK200 L1: 160MHz */
+	{ 4, 7, 5, 6, 1 },
+	/* ACLK200 L2: 133MHz */
+	{ 5, 7, 7, 7, 1 },
+};
+static unsigned int exynos4210_clkdiv_lr_bus[][2] = {
+	/*
+	 * Clock divider value for following
+	 * { DIVGDL/R, DIVGPL/R }
+	 */
+	/* ACLK_GDL/R L1: 200MHz */
+	{ 3, 1 },
+	/* ACLK_GDL/R L2: 160MHz */
+	{ 4, 1 },
+	/* ACLK_GDL/R L3: 133MHz */
+	{ 5, 1 },
+};
+
+/*** Clock Divider Data for Exynos4212/4412 ***/
+static unsigned int exynos4x12_clkdiv_dmc0[][6] = {
+	/*
+	 * Clock divider value for following
+	 * { DIVACP, DIVACP_PCLK, DIVDPHY, DIVDMC, DIVDMCD
+	 *              DIVDMCP}
+	 */
+
+	/* DMC L0: 400MHz */
+	{3, 1, 1, 1, 1, 1},
+	/* DMC L1: 266.7MHz */
+	{4, 1, 1, 2, 1, 1},
+	/* DMC L2: 160MHz */
+	{5, 1, 1, 4, 1, 1},
+	/* DMC L3: 133MHz */
+	{5, 1, 1, 5, 1, 1},
+	/* DMC L4: 100MHz */
+	{7, 1, 1, 7, 1, 1},
+};
+static unsigned int exynos4x12_clkdiv_dmc1[][6] = {
+	/*
+	 * Clock divider value for following
+	 * { G2DACP, DIVC2C, DIVC2C_ACLK }
+	 */
+
+	/* DMC L0: 400MHz */
+	{3, 1, 1},
+	/* DMC L1: 266.7MHz */
+	{4, 2, 1},
+	/* DMC L2: 160MHz */
+	{5, 4, 1},
+	/* DMC L3: 133MHz */
+	{5, 5, 1},
+	/* DMC L4: 100MHz */
+	{7, 7, 1},
+};
+static unsigned int exynos4x12_clkdiv_top[][5] = {
+	/*
+	 * Clock divider value for following
+	 * { DIVACLK266_GPS, DIVACLK100, DIVACLK160,
+		DIVACLK133, DIVONENAND }
+	 */
+
+	/* ACLK_GDL/R L0: 200MHz */
+	{2, 7, 4, 5, 1},
+	/* ACLK_GDL/R L1: 200MHz */
+	{2, 7, 4, 5, 1},
+	/* ACLK_GDL/R L2: 160MHz */
+	{4, 7, 5, 7, 1},
+	/* ACLK_GDL/R L3: 133MHz */
+	{4, 7, 5, 7, 1},
+	/* ACLK_GDL/R L4: 100MHz */
+	{7, 7, 7, 7, 1},
+};
+static unsigned int exynos4x12_clkdiv_lr_bus[][2] = {
+	/*
+	 * Clock divider value for following
+	 * { DIVGDL/R, DIVGPL/R }
+	 */
+
+	/* ACLK_GDL/R L0: 200MHz */
+	{3, 1},
+	/* ACLK_GDL/R L1: 200MHz */
+	{3, 1},
+	/* ACLK_GDL/R L2: 160MHz */
+	{4, 1},
+	/* ACLK_GDL/R L3: 133MHz */
+	{5, 1},
+	/* ACLK_GDL/R L4: 100MHz */
+	{7, 1},
+};
+static unsigned int exynos4x12_clkdiv_sclkip[][3] = {
+	/*
+	 * Clock divider value for following
+	 * { DIVMFC, DIVJPEG, DIVFIMC0~3}
+	 */
+
+	/* SCLK_MFC: 200MHz */
+	{3, 3, 4},
+	/* SCLK_MFC: 200MHz */
+	{3, 3, 4},
+	/* SCLK_MFC: 160MHz */
+	{4, 4, 5},
+	/* SCLK_MFC: 133MHz */
+	{5, 5, 5},
+	/* SCLK_MFC: 100MHz */
+	{7, 7, 7},
+};
+
+
+static int exynos4210_set_busclk(struct busfreq_data *data, struct opp *opp)
+{
+	unsigned int index;
+	unsigned int tmp;
+
+	for (index = LV_0; index < EX4210_LV_NUM; index++)
+		if (opp_get_freq(opp) == exynos4210_busclk_table[index].clk)
+			break;
+
+	if (index == EX4210_LV_NUM)
+		return -EINVAL;
+
+	/* Change Divider - DMC0 */
+	tmp = data->dmc_divtable[index];
+
+	__raw_writel(tmp, S5P_CLKDIV_DMC0);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_DMC0);
+	} while (tmp & 0x11111111);
+
+	/* Change Divider - TOP */
+	tmp = data->top_divtable[index];
+
+	__raw_writel(tmp, S5P_CLKDIV_TOP);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_TOP);
+	} while (tmp & 0x11111);
+
+	/* Change Divider - LEFTBUS */
+	tmp = __raw_readl(S5P_CLKDIV_LEFTBUS);
+
+	tmp &= ~(S5P_CLKDIV_BUS_GDLR_MASK | S5P_CLKDIV_BUS_GPLR_MASK);
+
+	tmp |= ((exynos4210_clkdiv_lr_bus[index][0] <<
+				S5P_CLKDIV_BUS_GDLR_SHIFT) |
+		(exynos4210_clkdiv_lr_bus[index][1] <<
+				S5P_CLKDIV_BUS_GPLR_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_LEFTBUS);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_LEFTBUS);
+	} while (tmp & 0x11);
+
+	/* Change Divider - RIGHTBUS */
+	tmp = __raw_readl(S5P_CLKDIV_RIGHTBUS);
+
+	tmp &= ~(S5P_CLKDIV_BUS_GDLR_MASK | S5P_CLKDIV_BUS_GPLR_MASK);
+
+	tmp |= ((exynos4210_clkdiv_lr_bus[index][0] <<
+				S5P_CLKDIV_BUS_GDLR_SHIFT) |
+		(exynos4210_clkdiv_lr_bus[index][1] <<
+				S5P_CLKDIV_BUS_GPLR_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_RIGHTBUS);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_RIGHTBUS);
+	} while (tmp & 0x11);
+
+	return 0;
+}
+
+static int exynos4x12_set_busclk(struct busfreq_data *data, struct opp *opp)
+{
+	unsigned int index;
+	unsigned int tmp;
+
+	for (index = LV_0; index < EX4x12_LV_NUM; index++)
+		if (opp_get_freq(opp) == exynos4x12_mifclk_table[index].clk)
+			break;
+
+	if (index == EX4x12_LV_NUM)
+		return -EINVAL;
+
+	/* Change Divider - DMC0 */
+	tmp = data->dmc_divtable[index];
+
+	__raw_writel(tmp, S5P_CLKDIV_DMC0);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_DMC0);
+	} while (tmp & 0x11111111);
+
+	/* Change Divider - DMC1 */
+	tmp = __raw_readl(S5P_CLKDIV_DMC1);
+
+	tmp &= ~(S5P_CLKDIV_DMC1_G2D_ACP_MASK |
+		S5P_CLKDIV_DMC1_C2C_MASK |
+		S5P_CLKDIV_DMC1_C2CACLK_MASK);
+
+	tmp |= ((exynos4x12_clkdiv_dmc1[index][0] <<
+				S5P_CLKDIV_DMC1_G2D_ACP_SHIFT) |
+		(exynos4x12_clkdiv_dmc1[index][1] <<
+				S5P_CLKDIV_DMC1_C2C_SHIFT) |
+		(exynos4x12_clkdiv_dmc1[index][2] <<
+				S5P_CLKDIV_DMC1_C2CACLK_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_DMC1);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_DMC1);
+	} while (tmp & 0x111111);
+
+	/* Change Divider - TOP */
+	tmp = __raw_readl(S5P_CLKDIV_TOP);
+
+	tmp &= ~(S5P_CLKDIV_TOP_ACLK266_GPS_MASK |
+		S5P_CLKDIV_TOP_ACLK100_MASK |
+		S5P_CLKDIV_TOP_ACLK160_MASK |
+		S5P_CLKDIV_TOP_ACLK133_MASK |
+		S5P_CLKDIV_TOP_ONENAND_MASK);
+
+	tmp |= ((exynos4x12_clkdiv_top[index][0] <<
+				S5P_CLKDIV_TOP_ACLK266_GPS_SHIFT) |
+		(exynos4x12_clkdiv_top[index][1] <<
+				S5P_CLKDIV_TOP_ACLK100_SHIFT) |
+		(exynos4x12_clkdiv_top[index][2] <<
+				S5P_CLKDIV_TOP_ACLK160_SHIFT) |
+		(exynos4x12_clkdiv_top[index][3] <<
+				S5P_CLKDIV_TOP_ACLK133_SHIFT) |
+		(exynos4x12_clkdiv_top[index][4] <<
+				S5P_CLKDIV_TOP_ONENAND_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_TOP);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_TOP);
+	} while (tmp & 0x11111);
+
+	/* Change Divider - LEFTBUS */
+	tmp = __raw_readl(S5P_CLKDIV_LEFTBUS);
+
+	tmp &= ~(S5P_CLKDIV_BUS_GDLR_MASK | S5P_CLKDIV_BUS_GPLR_MASK);
+
+	tmp |= ((exynos4x12_clkdiv_lr_bus[index][0] <<
+				S5P_CLKDIV_BUS_GDLR_SHIFT) |
+		(exynos4x12_clkdiv_lr_bus[index][1] <<
+				S5P_CLKDIV_BUS_GPLR_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_LEFTBUS);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_LEFTBUS);
+	} while (tmp & 0x11);
+
+	/* Change Divider - RIGHTBUS */
+	tmp = __raw_readl(S5P_CLKDIV_RIGHTBUS);
+
+	tmp &= ~(S5P_CLKDIV_BUS_GDLR_MASK | S5P_CLKDIV_BUS_GPLR_MASK);
+
+	tmp |= ((exynos4x12_clkdiv_lr_bus[index][0] <<
+				S5P_CLKDIV_BUS_GDLR_SHIFT) |
+		(exynos4x12_clkdiv_lr_bus[index][1] <<
+				S5P_CLKDIV_BUS_GPLR_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_RIGHTBUS);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_RIGHTBUS);
+	} while (tmp & 0x11);
+
+	/* Change Divider - MFC */
+	tmp = __raw_readl(S5P_CLKDIV_MFC);
+
+	tmp &= ~(S5P_CLKDIV_MFC_MASK);
+
+	tmp |= ((exynos4x12_clkdiv_sclkip[index][0] <<
+				S5P_CLKDIV_MFC_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_MFC);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_MFC);
+	} while (tmp & 0x1);
+
+	/* Change Divider - JPEG */
+	tmp = __raw_readl(S5P_CLKDIV_CAM1);
+
+	tmp &= ~(S5P_CLKDIV_CAM1_JPEG_MASK);
+
+	tmp |= ((exynos4x12_clkdiv_sclkip[index][1] <<
+				S5P_CLKDIV_CAM1_JPEG_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_CAM1);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_CAM1);
+	} while (tmp & 0x1);
+
+	/* Change Divider - FIMC0~3 */
+	tmp = __raw_readl(S5P_CLKDIV_CAM);
+
+	tmp &= ~(S5P_CLKDIV_CAM_FIMC0_MASK | S5P_CLKDIV_CAM_FIMC1_MASK |
+		S5P_CLKDIV_CAM_FIMC2_MASK | S5P_CLKDIV_CAM_FIMC3_MASK);
+
+	tmp |= ((exynos4x12_clkdiv_sclkip[index][2] <<
+				S5P_CLKDIV_CAM_FIMC0_SHIFT) |
+		(exynos4x12_clkdiv_sclkip[index][2] <<
+				S5P_CLKDIV_CAM_FIMC1_SHIFT) |
+		(exynos4x12_clkdiv_sclkip[index][2] <<
+				S5P_CLKDIV_CAM_FIMC2_SHIFT) |
+		(exynos4x12_clkdiv_sclkip[index][2] <<
+				S5P_CLKDIV_CAM_FIMC3_SHIFT));
+
+	__raw_writel(tmp, S5P_CLKDIV_CAM);
+
+	do {
+		tmp = __raw_readl(S5P_CLKDIV_STAT_CAM1);
+	} while (tmp & 0x1111);
+
+	return 0;
+}
+
+
+static void busfreq_mon_reset(struct busfreq_data *data)
+{
+	unsigned int i;
+
+	for (i = 0; i < 2; i++) {
+		void __iomem *ppmu_base = data->dmc[i].hw_base;
+
+		/* Reset PPMU */
+		__raw_writel(0x8000000f, ppmu_base + 0xf010);
+		__raw_writel(0x8000000f, ppmu_base + 0xf050);
+		__raw_writel(0x6, ppmu_base + 0xf000);
+		__raw_writel(0x0, ppmu_base + 0xf100);
+
+		/* Set PPMU Event */
+		data->dmc[i].event = 0x6;
+		__raw_writel(((data->dmc[i].event << 12) | 0x1),
+			     ppmu_base + 0xfc);
+
+		/* Start PPMU */
+		__raw_writel(0x1, ppmu_base + 0xf000);
+	}
+}
+
+static void exynos4_read_ppmu(struct busfreq_data *data)
+{
+	int i, j;
+
+	for (i = 0; i < 2; i++) {
+		void __iomem *ppmu_base = data->dmc[i].hw_base;
+		u32 overflow;
+
+		/* Stop PPMU */
+		__raw_writel(0x0, ppmu_base + 0xf000);
+
+		/* Update local data from PPMU */
+		overflow = __raw_readl(ppmu_base + 0xf050);
+
+		data->dmc[i].ccnt = __raw_readl(ppmu_base + 0xf100);
+		data->dmc[i].ccnt_overflow = overflow & (1 << 31);
+
+		for (j = 0; j < PPMU_PMNCNT_MAX; j++) {
+			data->dmc[i].count[j] = __raw_readl(
+					ppmu_base + (0xf110 + (0x10 * j)));
+			data->dmc[i].count_overflow[j] = overflow & (1 << j);
+		}
+	}
+
+	busfreq_mon_reset(data);
+}
+
+static int exynos4x12_get_intspec(unsigned long mifclk)
+{
+	int i = 0;
+
+	while (exynos4x12_intclk_table[i].clk) {
+		if (exynos4x12_intclk_table[i].clk <= mifclk)
+			return i;
+		i++;
+	}
+
+	return -EINVAL;
+}
+
+static int exynos4_bus_setvolt(struct busfreq_data *data, struct opp *opp,
+			       struct opp *oldopp)
+{
+	int err = 0, tmp;
+	unsigned long volt = opp_get_voltage(opp);
+
+	switch (data->type) {
+	case TYPE_BUSF_EXYNOS4210:
+		/* OPP represents DMC clock + INT voltage */
+		err = regulator_set_voltage(data->vdd_int, volt,
+					    MAX_SAFEVOLT);
+		break;
+	case TYPE_BUSF_EXYNOS4x12:
+		/* OPP represents MIF clock + MIF voltage */
+		err = regulator_set_voltage(data->vdd_mif, volt,
+					    MAX_SAFEVOLT);
+		if (err)
+			break;
+
+		tmp = exynos4x12_get_intspec(opp_get_freq(opp));
+		if (tmp < 0) {
+			err = tmp;
+			regulator_set_voltage(data->vdd_mif,
+					      opp_get_voltage(oldopp),
+					      MAX_SAFEVOLT);
+			break;
+		}
+		err = regulator_set_voltage(data->vdd_int,
+					    exynos4x12_intclk_table[tmp].volt,
+					    MAX_SAFEVOLT);
+		/*  Try to recover */
+		if (err)
+			regulator_set_voltage(data->vdd_mif,
+					      opp_get_voltage(oldopp),
+					      MAX_SAFEVOLT);
+		break;
+	default:
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+static int exynos4_bus_target(struct device *dev, unsigned long *_freq)
+{
+	int err = 0;
+	struct platform_device *pdev = container_of(dev, struct platform_device,
+						    dev);
+	struct busfreq_data *data = platform_get_drvdata(pdev);
+	struct opp *opp = devfreq_recommended_opp(dev, _freq);
+	unsigned long old_freq = opp_get_freq(data->curr_opp);
+	unsigned long freq = opp_get_freq(opp);
+
+	if (old_freq == freq)
+		return 0;
+
+	dev_dbg(dev, "targetting %lukHz %luuV\n", freq, opp_get_voltage(opp));
+
+	mutex_lock(&data->lock);
+
+	if (data->disabled)
+		goto out;
+
+	if (old_freq < freq)
+		err = exynos4_bus_setvolt(data, opp, data->curr_opp);
+	if (err)
+		goto out;
+
+	if (old_freq != freq) {
+		switch (data->type) {
+		case TYPE_BUSF_EXYNOS4210:
+			err = exynos4210_set_busclk(data, opp);
+			break;
+		case TYPE_BUSF_EXYNOS4x12:
+			err = exynos4x12_set_busclk(data, opp);
+			break;
+		default:
+			err = -EINVAL;
+		}
+	}
+	if (err)
+		goto out;
+
+	if (old_freq > freq)
+		err = exynos4_bus_setvolt(data, opp, data->curr_opp);
+	if (err)
+		goto out;
+
+	data->curr_opp = opp;
+out:
+	mutex_unlock(&data->lock);
+	return err;
+}
+
+static int exynos4_get_busier_dmc(struct busfreq_data *data)
+{
+	u64 p0 = data->dmc[0].count[0];
+	u64 p1 = data->dmc[1].count[0];
+
+	p0 *= data->dmc[1].ccnt;
+	p1 *= data->dmc[0].ccnt;
+
+	if (data->dmc[1].ccnt == 0)
+		return 0;
+
+	if (p0 > p1)
+		return 0;
+	return 1;
+}
+
+static int exynos4_bus_get_dev_status(struct device *dev,
+				      struct devfreq_dev_status *stat)
+{
+	struct platform_device *pdev = container_of(dev, struct platform_device,
+						    dev);
+	struct busfreq_data *data = platform_get_drvdata(pdev);
+	int busier_dmc;
+	int cycles_x2 = 2; /* 2 x cycles */
+	void __iomem *addr;
+	u32 timing;
+	u32 memctrl;
+
+	exynos4_read_ppmu(data);
+	busier_dmc = exynos4_get_busier_dmc(data);
+	stat->current_frequency = opp_get_freq(data->curr_opp);
+
+	if (busier_dmc)
+		addr = S5P_VA_DMC1;
+	else
+		addr = S5P_VA_DMC0;
+
+	memctrl = __raw_readl(addr + 0x04); /* one of DDR2/3/LPDDR2 */
+	timing = __raw_readl(addr + 0x38); /* CL or WL/RL values */
+
+	switch ((memctrl >> 8) & 0xf) {
+	case 0x4: /* DDR2 */
+		cycles_x2 = ((timing >> 16) & 0xf) * 2;
+		break;
+	case 0x5: /* LPDDR2 */
+	case 0x6: /* DDR3 */
+		cycles_x2 = ((timing >> 8) & 0xf) + ((timing >> 0) & 0xf);
+		break;
+	default:
+		pr_err("%s: Unknown Memory Type(%d).\n", __func__,
+		       (memctrl >> 8) & 0xf);
+		return -EINVAL;
+	}
+
+	/* Number of cycles spent on memory access */
+	stat->busy_time = data->dmc[busier_dmc].count[0] / 2 * (cycles_x2 + 2);
+	stat->busy_time *= 100 / BUS_SATURATION_RATIO;
+	stat->total_time = data->dmc[busier_dmc].ccnt;
+
+	/* If the counters have overflown, retry */
+	if (data->dmc[busier_dmc].ccnt_overflow ||
+	    data->dmc[busier_dmc].count_overflow[0])
+		return -EAGAIN;
+
+	return 0;
+}
+
+static void exynos4_bus_exit(struct device *dev)
+{
+	struct platform_device *pdev = container_of(dev, struct platform_device,
+						    dev);
+	struct busfreq_data *data = platform_get_drvdata(pdev);
+
+	devfreq_unregister_opp_notifier(dev, data->devfreq);
+}
+
+static struct devfreq_dev_profile exynos4_devfreq_profile = {
+	.initial_freq	= 400000,
+	.polling_ms	= 50,
+	.target		= exynos4_bus_target,
+	.get_dev_status	= exynos4_bus_get_dev_status,
+	.exit		= exynos4_bus_exit,
+};
+
+static int exynos4210_init_tables(struct busfreq_data *data)
+{
+	u32 tmp;
+	int mgrp;
+	int i, err = 0;
+
+	tmp = __raw_readl(S5P_CLKDIV_DMC0);
+	for (i = LV_0; i < EX4210_LV_NUM; i++) {
+		tmp &= ~(S5P_CLKDIV_DMC0_ACP_MASK |
+			S5P_CLKDIV_DMC0_ACPPCLK_MASK |
+			S5P_CLKDIV_DMC0_DPHY_MASK |
+			S5P_CLKDIV_DMC0_DMC_MASK |
+			S5P_CLKDIV_DMC0_DMCD_MASK |
+			S5P_CLKDIV_DMC0_DMCP_MASK |
+			S5P_CLKDIV_DMC0_COPY2_MASK |
+			S5P_CLKDIV_DMC0_CORETI_MASK);
+
+		tmp |= ((exynos4210_clkdiv_dmc0[i][0] <<
+					S5P_CLKDIV_DMC0_ACP_SHIFT) |
+			(exynos4210_clkdiv_dmc0[i][1] <<
+					S5P_CLKDIV_DMC0_ACPPCLK_SHIFT) |
+			(exynos4210_clkdiv_dmc0[i][2] <<
+					S5P_CLKDIV_DMC0_DPHY_SHIFT) |
+			(exynos4210_clkdiv_dmc0[i][3] <<
+					S5P_CLKDIV_DMC0_DMC_SHIFT) |
+			(exynos4210_clkdiv_dmc0[i][4] <<
+					S5P_CLKDIV_DMC0_DMCD_SHIFT) |
+			(exynos4210_clkdiv_dmc0[i][5] <<
+					S5P_CLKDIV_DMC0_DMCP_SHIFT) |
+			(exynos4210_clkdiv_dmc0[i][6] <<
+					S5P_CLKDIV_DMC0_COPY2_SHIFT) |
+			(exynos4210_clkdiv_dmc0[i][7] <<
+					S5P_CLKDIV_DMC0_CORETI_SHIFT));
+
+		data->dmc_divtable[i] = tmp;
+	}
+
+	tmp = __raw_readl(S5P_CLKDIV_TOP);
+	for (i = LV_0; i <  EX4210_LV_NUM; i++) {
+		tmp &= ~(S5P_CLKDIV_TOP_ACLK200_MASK |
+			S5P_CLKDIV_TOP_ACLK100_MASK |
+			S5P_CLKDIV_TOP_ACLK160_MASK |
+			S5P_CLKDIV_TOP_ACLK133_MASK |
+			S5P_CLKDIV_TOP_ONENAND_MASK);
+
+		tmp |= ((exynos4210_clkdiv_top[i][0] <<
+					S5P_CLKDIV_TOP_ACLK200_SHIFT) |
+			(exynos4210_clkdiv_top[i][1] <<
+					S5P_CLKDIV_TOP_ACLK100_SHIFT) |
+			(exynos4210_clkdiv_top[i][2] <<
+					S5P_CLKDIV_TOP_ACLK160_SHIFT) |
+			(exynos4210_clkdiv_top[i][3] <<
+					S5P_CLKDIV_TOP_ACLK133_SHIFT) |
+			(exynos4210_clkdiv_top[i][4] <<
+					S5P_CLKDIV_TOP_ONENAND_SHIFT));
+
+		data->top_divtable[i] = tmp;
+	}
+
+#ifdef CONFIG_EXYNOS_ASV
+	tmp = exynos4_result_of_asv;
+#else
+	tmp = 0; /* Max voltages for the reliability of the unknown */
+#endif
+
+	pr_debug("ASV Group of Exynos4 is %d\n", tmp);
+	/* Use merged grouping for voltage */
+	switch (tmp) {
+	case 0:
+		mgrp = 0;
+		break;
+	case 1:
+	case 2:
+		mgrp = 1;
+		break;
+	case 3:
+	case 4:
+		mgrp = 2;
+		break;
+	case 5:
+	case 6:
+		mgrp = 3;
+		break;
+	case 7:
+		mgrp = 4;
+		break;
+	default:
+		pr_warn("Unknown ASV Group. Use max voltage.\n");
+		mgrp = 0;
+	}
+
+	for (i = LV_0; i < EX4210_LV_NUM; i++)
+		exynos4210_busclk_table[i].volt = exynos4210_asv_volt[mgrp][i];
+
+	for (i = LV_0; i < EX4210_LV_NUM; i++) {
+		err = opp_add(data->dev, exynos4210_busclk_table[i].clk,
+			      exynos4210_busclk_table[i].volt);
+		if (err) {
+			dev_err(data->dev, "Cannot add opp entries.\n");
+			return err;
+		}
+	}
+
+
+	return 0;
+}
+
+static int exynos4x12_init_tables(struct busfreq_data *data)
+{
+	unsigned int i;
+	unsigned int tmp;
+	int ret;
+
+	/* Enable pause function for DREX2 DVFS */
+	tmp = __raw_readl(S5P_DMC_PAUSE_CTRL);
+	tmp |= DMC_PAUSE_ENABLE;
+	__raw_writel(tmp, S5P_DMC_PAUSE_CTRL);
+
+	tmp = __raw_readl(S5P_CLKDIV_DMC0);
+
+	for (i = 0; i <  EX4x12_LV_NUM; i++) {
+		tmp &= ~(S5P_CLKDIV_DMC0_ACP_MASK |
+			S5P_CLKDIV_DMC0_ACPPCLK_MASK |
+			S5P_CLKDIV_DMC0_DPHY_MASK |
+			S5P_CLKDIV_DMC0_DMC_MASK |
+			S5P_CLKDIV_DMC0_DMCD_MASK |
+			S5P_CLKDIV_DMC0_DMCP_MASK);
+
+		tmp |= ((exynos4x12_clkdiv_dmc0[i][0] <<
+					S5P_CLKDIV_DMC0_ACP_SHIFT) |
+			(exynos4x12_clkdiv_dmc0[i][1] <<
+					S5P_CLKDIV_DMC0_ACPPCLK_SHIFT) |
+			(exynos4x12_clkdiv_dmc0[i][2] <<
+					S5P_CLKDIV_DMC0_DPHY_SHIFT) |
+			(exynos4x12_clkdiv_dmc0[i][3] <<
+					S5P_CLKDIV_DMC0_DMC_SHIFT) |
+			(exynos4x12_clkdiv_dmc0[i][4] <<
+					S5P_CLKDIV_DMC0_DMCD_SHIFT) |
+			(exynos4x12_clkdiv_dmc0[i][5] <<
+					S5P_CLKDIV_DMC0_DMCP_SHIFT));
+
+		data->dmc_divtable[i] = tmp;
+	}
+
+#ifdef CONFIG_EXYNOS_ASV
+	tmp = exynos4_result_of_asv;
+#else
+	tmp = 0; /* Max voltages for the reliability of the unknown */
+#endif
+
+	if (tmp > 8)
+		tmp = 0;
+	pr_debug("ASV Group of Exynos4x12 is %d\n", tmp);
+
+	for (i = 0; i < EX4x12_LV_NUM; i++) {
+		exynos4x12_mifclk_table[i].volt =
+			exynos4x12_mif_step_50[tmp][i];
+		exynos4x12_intclk_table[i].volt =
+			exynos4x12_int_volt[tmp][i];
+	}
+
+	for (i = 0; i < EX4x12_LV_NUM; i++) {
+		ret = opp_add(data->dev, exynos4x12_mifclk_table[i].clk,
+			      exynos4x12_mifclk_table[i].volt);
+		if (ret) {
+			dev_err(data->dev, "Fail to add opp entries.\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int exynos4_busfreq_pm_notifier_event(struct notifier_block *this,
+		unsigned long event, void *ptr)
+{
+	struct busfreq_data *data = container_of(this, struct busfreq_data,
+						 pm_notifier);
+	struct opp *opp;
+	unsigned long maxfreq = ULONG_MAX;
+	int err = 0;
+
+	switch (event) {
+	case PM_SUSPEND_PREPARE:
+		/* Set Fastest and Deactivate DVFS */
+		mutex_lock(&data->lock);
+
+		data->disabled = true;
+
+		opp = opp_find_freq_floor(data->dev, &maxfreq);
+
+		err = exynos4_bus_setvolt(data, opp, data->curr_opp);
+		if (err)
+			goto unlock;
+
+		switch (data->type) {
+		case TYPE_BUSF_EXYNOS4210:
+			err = exynos4210_set_busclk(data, opp);
+			break;
+		case TYPE_BUSF_EXYNOS4x12:
+			err = exynos4x12_set_busclk(data, opp);
+			break;
+		default:
+			err = -EINVAL;
+		}
+		if (err)
+			goto unlock;
+
+		data->curr_opp = opp;
+unlock:
+		mutex_unlock(&data->lock);
+		if (err)
+			return err;
+		return NOTIFY_OK;
+	case PM_POST_RESTORE:
+	case PM_POST_SUSPEND:
+		/* Reactivate */
+		mutex_lock(&data->lock);
+		data->disabled = false;
+		mutex_unlock(&data->lock);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static __devinit int exynos4_busfreq_probe(struct platform_device *pdev)
+{
+	struct busfreq_data *data;
+	struct opp *opp;
+	struct device *dev = &pdev->dev;
+	int err = 0;
+
+	data = kzalloc(sizeof(struct busfreq_data), GFP_KERNEL);
+	if (data == NULL) {
+		dev_err(dev, "Cannot allocate memory.\n");
+		return -ENOMEM;
+	}
+
+	data->type = pdev->id_entry->driver_data;
+	data->dmc[0].hw_base = S5P_VA_DMC0;
+	data->dmc[1].hw_base = S5P_VA_DMC1;
+	data->pm_notifier.notifier_call = exynos4_busfreq_pm_notifier_event;
+	data->dev = dev;
+	mutex_init(&data->lock);
+
+	switch (data->type) {
+	case TYPE_BUSF_EXYNOS4210:
+		err = exynos4210_init_tables(data);
+		break;
+	case TYPE_BUSF_EXYNOS4x12:
+		err = exynos4x12_init_tables(data);
+		break;
+	default:
+		dev_err(dev, "Cannot determine the device id %d\n", data->type);
+		err = -EINVAL;
+	}
+	if (err)
+		goto err_regulator;
+
+	data->vdd_int = regulator_get(dev, "vdd_int");
+	if (IS_ERR(data->vdd_int)) {
+		dev_err(dev, "Cannot get the regulator \"vdd_int\"\n");
+		err = PTR_ERR(data->vdd_int);
+		goto err_regulator;
+	}
+	if (data->type == TYPE_BUSF_EXYNOS4x12) {
+		data->vdd_mif = regulator_get(dev, "vdd_mif");
+		if (IS_ERR(data->vdd_mif)) {
+			dev_err(dev, "Cannot get the regulator \"vdd_mif\"\n");
+			err = PTR_ERR(data->vdd_mif);
+			regulator_put(data->vdd_int);
+			goto err_regulator;
+
+		}
+	}
+
+	opp = opp_find_freq_floor(dev, &exynos4_devfreq_profile.initial_freq);
+	if (IS_ERR(opp)) {
+		dev_err(dev, "Invalid initial frequency %lu kHz.\n",
+		       exynos4_devfreq_profile.initial_freq);
+		err = PTR_ERR(opp);
+		goto err_opp_add;
+	}
+	data->curr_opp = opp;
+
+	platform_set_drvdata(pdev, data);
+
+	busfreq_mon_reset(data);
+
+	data->devfreq = devfreq_add_device(dev, &exynos4_devfreq_profile,
+					   &devfreq_simple_ondemand, NULL);
+	if (IS_ERR(data->devfreq)) {
+		err = PTR_ERR(data->devfreq);
+		goto err_opp_add;
+	}
+
+	devfreq_register_opp_notifier(dev, data->devfreq);
+
+	err = register_pm_notifier(&data->pm_notifier);
+	if (err) {
+		dev_err(dev, "Failed to setup pm notifier\n");
+		goto err_devfreq_add;
+	}
+
+	return 0;
+err_devfreq_add:
+	devfreq_remove_device(data->devfreq);
+err_opp_add:
+	if (data->vdd_mif)
+		regulator_put(data->vdd_mif);
+	regulator_put(data->vdd_int);
+err_regulator:
+	kfree(data);
+	return err;
+}
+
+static __devexit int exynos4_busfreq_remove(struct platform_device *pdev)
+{
+	struct busfreq_data *data = platform_get_drvdata(pdev);
+
+	unregister_pm_notifier(&data->pm_notifier);
+	devfreq_remove_device(data->devfreq);
+	regulator_put(data->vdd_int);
+	if (data->vdd_mif)
+		regulator_put(data->vdd_mif);
+	kfree(data);
+
+	return 0;
+}
+
+static int exynos4_busfreq_resume(struct device *dev)
+{
+	struct platform_device *pdev = container_of(dev, struct platform_device,
+						    dev);
+	struct busfreq_data *data = platform_get_drvdata(pdev);
+
+	busfreq_mon_reset(data);
+	return 0;
+}
+
+static const struct dev_pm_ops exynos4_busfreq_pm = {
+	.resume	= exynos4_busfreq_resume,
+};
+
+static const struct platform_device_id exynos4_busfreq_id[] = {
+	{ "exynos4210-busfreq", TYPE_BUSF_EXYNOS4210 },
+	{ "exynos4412-busfreq", TYPE_BUSF_EXYNOS4x12 },
+	{ "exynos4212-busfreq", TYPE_BUSF_EXYNOS4x12 },
+	{ },
+};
+
+static struct platform_driver exynos4_busfreq_driver = {
+	.probe	= exynos4_busfreq_probe,
+	.remove	= __devexit_p(exynos4_busfreq_remove),
+	.id_table = exynos4_busfreq_id,
+	.driver = {
+		.name	= "exynos4-busfreq",
+		.owner	= THIS_MODULE,
+		.pm	= &exynos4_busfreq_pm,
+	},
+};
+
+static int __init exynos4_busfreq_init(void)
+{
+	return platform_driver_register(&exynos4_busfreq_driver);
+}
+late_initcall(exynos4_busfreq_init);
+
+static void __exit exynos4_busfreq_exit(void)
+{
+	platform_driver_unregister(&exynos4_busfreq_driver);
+}
+module_exit(exynos4_busfreq_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("EXYNOS4 busfreq driver with devfreq framework");
+MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
+MODULE_ALIAS("exynos4-busfreq");