PM/Devfreq: Add Exynos4-bus device DVFS driver for Exynos4210/4212/4412.

Exynos4-bus device devfreq driver add DVFS capability for
Exynos4210/4212/4412-Bus (memory). The driver monitors PPMU counters of memory
controllers and adjusts operating frequencies and voltages with OPP.
For Exynos4210, vdd_int is controlled. For exynos4412/4212, vdd_mif and
vdd_int are controlled.

Dependency (CONFIG_EXYNOS_ASV):
Exynos4 ASV driver has been posted in the mailing list; however, it
si not yet upstreamed. Although the current revision of Exynos4 ASV
patch does not contain "CONFIG_EXYNOS_ASV", we have added the symbol
to hide the dependent from compilers for now. As soon as Exynos4 ASV
drivers are merged, the #ifdef statement will be removed or the
name will be changed.

However, enabling ASV is essential in most Exynos4 chips to reduce
the power consumption of Exynos4210 because without ASV, this Devfreq
driver assumes the worst case scenario, which consumes more power.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

---
Changes from v1
- Support 4212 and 4412 as well as 4210.

1 files changed, 1135 insertions, 0 deletions

diff --git a/drivers/devfreq/exynos4_bus.c b/drivers/devfreq/exynos4_bus.c
new file mode 100644
index 00000000000..6460577d670
--- /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");