Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

5 files changed, 1879 insertions, 0 deletions

diff --git a/drivers/memory/samsung/Kconfig b/drivers/memory/samsung/Kconfig
new file mode 100644
index 000000000..7fb70f573
--- /dev/null
+++ b/drivers/memory/samsung/Kconfig
@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: GPL-2.0
+config SAMSUNG_MC
+	bool "Samsung Exynos Memory Controller support" if COMPILE_TEST
+	help
+	  Support for the Memory Controller (MC) devices found on
+	  Samsung Exynos SoCs.
+
+if SAMSUNG_MC
+
+config EXYNOS5422_DMC
+	tristate "Exynos5422 Dynamic Memory Controller driver"
+	depends on ARCH_EXYNOS || (COMPILE_TEST && HAS_IOMEM)
+	select DDR
+	depends on DEVFREQ_GOV_SIMPLE_ONDEMAND
+	depends on (PM_DEVFREQ && PM_DEVFREQ_EVENT)
+	help
+	  This adds driver for Samsung Exynos5422 SoC DMC (Dynamic Memory
+	  Controller).  The driver provides support for Dynamic Voltage and
+	  Frequency Scaling in DMC and DRAM. It also supports changing timings
+	  of DRAM running with different frequency. The timings are calculated
+	  based on DT memory information.
+	  If unsure, say Y on devices with Samsung Exynos SoCs.
+
+config EXYNOS_SROM
+	bool "Exynos SROM controller driver" if COMPILE_TEST
+	depends on (ARM && ARCH_EXYNOS) || (COMPILE_TEST && HAS_IOMEM)
+	help
+	  This adds driver for Samsung Exynos SoC SROM controller.  The driver
+	  in basic operation mode only saves and restores SROM registers
+	  during suspend.  If however appropriate device tree configuration
+	  is provided, the driver enables support for external memory
+	  or external devices.
+	  If unsure, say Y on devices with Samsung Exynos SoCs.
+
+endif
diff --git a/drivers/memory/samsung/Makefile b/drivers/memory/samsung/Makefile
new file mode 100644
index 000000000..ea071be21
--- /dev/null
+++ b/drivers/memory/samsung/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_EXYNOS5422_DMC)	+= exynos5422-dmc.o
+obj-$(CONFIG_EXYNOS_SROM)	+= exynos-srom.o
diff --git a/drivers/memory/samsung/exynos-srom.c b/drivers/memory/samsung/exynos-srom.c
new file mode 100644
index 000000000..fcef4aed0
--- /dev/null
+++ b/drivers/memory/samsung/exynos-srom.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2015 Samsung Electronics Co., Ltd.
+//	      http://www.samsung.com/
+//
+// Exynos - SROM Controller support
+// Author: Pankaj Dubey <pankaj.dubey@samsung.com>
+
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "exynos-srom.h"
+
+static const unsigned long exynos_srom_offsets[] = {
+	/* SROM side */
+	EXYNOS_SROM_BW,
+	EXYNOS_SROM_BC0,
+	EXYNOS_SROM_BC1,
+	EXYNOS_SROM_BC2,
+	EXYNOS_SROM_BC3,
+};
+
+/**
+ * struct exynos_srom_reg_dump: register dump of SROM Controller registers.
+ * @offset: srom register offset from the controller base address.
+ * @value: the value of register under the offset.
+ */
+struct exynos_srom_reg_dump {
+	u32     offset;
+	u32     value;
+};
+
+/**
+ * struct exynos_srom: platform data for exynos srom controller driver.
+ * @dev: platform device pointer
+ * @reg_base: srom base address
+ * @reg_offset: exynos_srom_reg_dump pointer to hold offset and its value.
+ */
+struct exynos_srom {
+	struct device *dev;
+	void __iomem *reg_base;
+	struct exynos_srom_reg_dump *reg_offset;
+};
+
+static struct exynos_srom_reg_dump *
+exynos_srom_alloc_reg_dump(const unsigned long *rdump,
+			   unsigned long nr_rdump)
+{
+	struct exynos_srom_reg_dump *rd;
+	unsigned int i;
+
+	rd = kzalloc_objs(*rd, nr_rdump);
+	if (!rd)
+		return NULL;
+
+	for (i = 0; i < nr_rdump; ++i)
+		rd[i].offset = rdump[i];
+
+	return rd;
+}
+
+static int exynos_srom_configure_bank(struct exynos_srom *srom,
+				      struct device_node *np)
+{
+	u32 bank, width, pmc = 0;
+	u32 timing[6];
+	u32 cs, bw;
+
+	if (of_property_read_u32(np, "reg", &bank))
+		return -EINVAL;
+	if (of_property_read_u32(np, "reg-io-width", &width))
+		width = 1;
+	if (of_property_read_bool(np, "samsung,srom-page-mode"))
+		pmc = 1 << EXYNOS_SROM_BCX__PMC__SHIFT;
+	if (of_property_read_u32_array(np, "samsung,srom-timing", timing,
+				       ARRAY_SIZE(timing)))
+		return -EINVAL;
+
+	bank *= 4; /* Convert bank into shift/offset */
+
+	cs = 1 << EXYNOS_SROM_BW__BYTEENABLE__SHIFT;
+	if (width == 2)
+		cs |= 1 << EXYNOS_SROM_BW__DATAWIDTH__SHIFT;
+
+	bw = readl_relaxed(srom->reg_base + EXYNOS_SROM_BW);
+	bw = (bw & ~(EXYNOS_SROM_BW__CS_MASK << bank)) | (cs << bank);
+	writel_relaxed(bw, srom->reg_base + EXYNOS_SROM_BW);
+
+	writel_relaxed(pmc | (timing[0] << EXYNOS_SROM_BCX__TACP__SHIFT) |
+		       (timing[1] << EXYNOS_SROM_BCX__TCAH__SHIFT) |
+		       (timing[2] << EXYNOS_SROM_BCX__TCOH__SHIFT) |
+		       (timing[3] << EXYNOS_SROM_BCX__TACC__SHIFT) |
+		       (timing[4] << EXYNOS_SROM_BCX__TCOS__SHIFT) |
+		       (timing[5] << EXYNOS_SROM_BCX__TACS__SHIFT),
+		       srom->reg_base + EXYNOS_SROM_BC0 + bank);
+
+	return 0;
+}
+
+static int exynos_srom_probe(struct platform_device *pdev)
+{
+	struct device_node *np, *child;
+	struct exynos_srom *srom;
+	struct device *dev = &pdev->dev;
+	bool bad_bank_config = false;
+
+	np = dev->of_node;
+	if (!np) {
+		dev_err(&pdev->dev, "could not find device info\n");
+		return -EINVAL;
+	}
+
+	srom = devm_kzalloc(&pdev->dev,
+			    sizeof(struct exynos_srom), GFP_KERNEL);
+	if (!srom)
+		return -ENOMEM;
+
+	srom->dev = dev;
+	srom->reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(srom->reg_base)) {
+		dev_err(&pdev->dev, "iomap of exynos srom controller failed\n");
+		return PTR_ERR(srom->reg_base);
+	}
+
+	platform_set_drvdata(pdev, srom);
+
+	srom->reg_offset = exynos_srom_alloc_reg_dump(exynos_srom_offsets,
+						      ARRAY_SIZE(exynos_srom_offsets));
+	if (!srom->reg_offset)
+		return -ENOMEM;
+
+	for_each_child_of_node(np, child) {
+		if (exynos_srom_configure_bank(srom, child)) {
+			dev_err(dev,
+				"Could not decode bank configuration for %pOFn\n",
+				child);
+			bad_bank_config = true;
+		}
+	}
+
+	/*
+	 * If any bank failed to configure, we still provide suspend/resume,
+	 * but do not probe child devices
+	 */
+	if (bad_bank_config)
+		return 0;
+
+	return of_platform_populate(np, NULL, NULL, dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static void exynos_srom_save(void __iomem *base,
+			     struct exynos_srom_reg_dump *rd,
+			     unsigned int num_regs)
+{
+	for (; num_regs > 0; --num_regs, ++rd)
+		rd->value = readl(base + rd->offset);
+}
+
+static void exynos_srom_restore(void __iomem *base,
+				const struct exynos_srom_reg_dump *rd,
+				unsigned int num_regs)
+{
+	for (; num_regs > 0; --num_regs, ++rd)
+		writel(rd->value, base + rd->offset);
+}
+
+static int exynos_srom_suspend(struct device *dev)
+{
+	struct exynos_srom *srom = dev_get_drvdata(dev);
+
+	exynos_srom_save(srom->reg_base, srom->reg_offset,
+			 ARRAY_SIZE(exynos_srom_offsets));
+	return 0;
+}
+
+static int exynos_srom_resume(struct device *dev)
+{
+	struct exynos_srom *srom = dev_get_drvdata(dev);
+
+	exynos_srom_restore(srom->reg_base, srom->reg_offset,
+			    ARRAY_SIZE(exynos_srom_offsets));
+	return 0;
+}
+#endif
+
+static const struct of_device_id of_exynos_srom_ids[] = {
+	{
+		.compatible	= "samsung,exynos4210-srom",
+	},
+	{},
+};
+
+static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume);
+
+static struct platform_driver exynos_srom_driver = {
+	.probe = exynos_srom_probe,
+	.driver = {
+		.name = "exynos-srom",
+		.of_match_table = of_exynos_srom_ids,
+		.pm = &exynos_srom_pm_ops,
+		.suppress_bind_attrs = true,
+	},
+};
+builtin_platform_driver(exynos_srom_driver);
diff --git a/drivers/memory/samsung/exynos-srom.h b/drivers/memory/samsung/exynos-srom.h
new file mode 100644
index 000000000..da612797f
--- /dev/null
+++ b/drivers/memory/samsung/exynos-srom.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * Exynos SROMC register definitions
+ */
+
+#ifndef __EXYNOS_SROM_H
+#define __EXYNOS_SROM_H __FILE__
+
+#define EXYNOS_SROMREG(x)		(x)
+
+#define EXYNOS_SROM_BW		EXYNOS_SROMREG(0x0)
+#define EXYNOS_SROM_BC0		EXYNOS_SROMREG(0x4)
+#define EXYNOS_SROM_BC1		EXYNOS_SROMREG(0x8)
+#define EXYNOS_SROM_BC2		EXYNOS_SROMREG(0xc)
+#define EXYNOS_SROM_BC3		EXYNOS_SROMREG(0x10)
+#define EXYNOS_SROM_BC4		EXYNOS_SROMREG(0x14)
+#define EXYNOS_SROM_BC5		EXYNOS_SROMREG(0x18)
+
+/* one register BW holds 4 x 4-bit packed settings for NCS0 - NCS3 */
+
+#define EXYNOS_SROM_BW__DATAWIDTH__SHIFT	0
+#define EXYNOS_SROM_BW__ADDRMODE__SHIFT		1
+#define EXYNOS_SROM_BW__WAITENABLE__SHIFT	2
+#define EXYNOS_SROM_BW__BYTEENABLE__SHIFT	3
+
+#define EXYNOS_SROM_BW__CS_MASK			0xf
+
+#define EXYNOS_SROM_BW__NCS0__SHIFT		0
+#define EXYNOS_SROM_BW__NCS1__SHIFT		4
+#define EXYNOS_SROM_BW__NCS2__SHIFT		8
+#define EXYNOS_SROM_BW__NCS3__SHIFT		12
+#define EXYNOS_SROM_BW__NCS4__SHIFT		16
+#define EXYNOS_SROM_BW__NCS5__SHIFT		20
+
+/* applies to same to BCS0 - BCS3 */
+
+#define EXYNOS_SROM_BCX__PMC__SHIFT		0
+#define EXYNOS_SROM_BCX__TACP__SHIFT		4
+#define EXYNOS_SROM_BCX__TCAH__SHIFT		8
+#define EXYNOS_SROM_BCX__TCOH__SHIFT		12
+#define EXYNOS_SROM_BCX__TACC__SHIFT		16
+#define EXYNOS_SROM_BCX__TCOS__SHIFT		24
+#define EXYNOS_SROM_BCX__TACS__SHIFT		28
+
+#endif /* __EXYNOS_SROM_H */
diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c
new file mode 100644
index 000000000..788d49c68
--- /dev/null
+++ b/drivers/memory/samsung/exynos5422-dmc.c
@@ -0,0 +1,1583 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019 Samsung Electronics Co., Ltd.
+ * Author: Lukasz Luba <l.luba@partner.samsung.com>
+ */
+
+#include <linux/cleanup.h>
+#include <linux/clk.h>
+#include <linux/devfreq.h>
+#include <linux/devfreq-event.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/pm_opp.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include "../jedec_ddr.h"
+#include "../of_memory.h"
+
+static int irqmode;
+module_param(irqmode, int, 0644);
+MODULE_PARM_DESC(irqmode, "Enable IRQ mode (0=off [default], 1=on)");
+
+#define EXYNOS5_DREXI_TIMINGAREF		(0x0030)
+#define EXYNOS5_DREXI_TIMINGROW0		(0x0034)
+#define EXYNOS5_DREXI_TIMINGDATA0		(0x0038)
+#define EXYNOS5_DREXI_TIMINGPOWER0		(0x003C)
+#define EXYNOS5_DREXI_TIMINGROW1		(0x00E4)
+#define EXYNOS5_DREXI_TIMINGDATA1		(0x00E8)
+#define EXYNOS5_DREXI_TIMINGPOWER1		(0x00EC)
+#define CDREX_PAUSE				(0x2091c)
+#define CDREX_LPDDR3PHY_CON3			(0x20a20)
+#define CDREX_LPDDR3PHY_CLKM_SRC		(0x20700)
+#define EXYNOS5_TIMING_SET_SWI			BIT(28)
+#define USE_MX_MSPLL_TIMINGS			(1)
+#define USE_BPLL_TIMINGS			(0)
+#define EXYNOS5_AREF_NORMAL			(0x2e)
+
+#define DREX_PPCCLKCON		(0x0130)
+#define DREX_PEREV2CONFIG	(0x013c)
+#define DREX_PMNC_PPC		(0xE000)
+#define DREX_CNTENS_PPC		(0xE010)
+#define DREX_CNTENC_PPC		(0xE020)
+#define DREX_INTENS_PPC		(0xE030)
+#define DREX_INTENC_PPC		(0xE040)
+#define DREX_FLAG_PPC		(0xE050)
+#define DREX_PMCNT2_PPC		(0xE130)
+
+/*
+ * A value for register DREX_PMNC_PPC which should be written to reset
+ * the cycle counter CCNT (a reference wall clock). It sets zero to the
+ * CCNT counter.
+ */
+#define CC_RESET		BIT(2)
+
+/*
+ * A value for register DREX_PMNC_PPC which does the reset of all performance
+ * counters to zero.
+ */
+#define PPC_COUNTER_RESET	BIT(1)
+
+/*
+ * Enables all configured counters (including cycle counter). The value should
+ * be written to the register DREX_PMNC_PPC.
+ */
+#define PPC_ENABLE		BIT(0)
+
+/* A value for register DREX_PPCCLKCON which enables performance events clock.
+ * Must be written before first access to the performance counters register
+ * set, otherwise it could crash.
+ */
+#define PEREV_CLK_EN		BIT(0)
+
+/*
+ * Values which are used to enable counters, interrupts or configure flags of
+ * the performance counters. They configure counter 2 and cycle counter.
+ */
+#define PERF_CNT2		BIT(2)
+#define PERF_CCNT		BIT(31)
+
+/*
+ * Performance event types which are used for setting the preferred event
+ * to track in the counters.
+ * There is a set of different types, the values are from range 0 to 0x6f.
+ * These settings should be written to the configuration register which manages
+ * the type of the event (register DREX_PEREV2CONFIG).
+ */
+#define READ_TRANSFER_CH0	(0x6d)
+#define READ_TRANSFER_CH1	(0x6f)
+
+#define PERF_COUNTER_START_VALUE 0xff000000
+#define PERF_EVENT_UP_DOWN_THRESHOLD 900000000ULL
+
+/**
+ * struct dmc_opp_table - Operating level desciption
+ * @freq_hz:		target frequency in Hz
+ * @volt_uv:		target voltage in uV
+ *
+ * Covers frequency and voltage settings of the DMC operating mode.
+ */
+struct dmc_opp_table {
+	u32 freq_hz;
+	u32 volt_uv;
+};
+
+/**
+ * struct exynos5_dmc - main structure describing DMC device
+ * @dev:		DMC device
+ * @df:			devfreq device structure returned by devfreq framework
+ * @gov_data:		configuration of devfreq governor
+ * @base_drexi0:	DREX0 registers mapping
+ * @base_drexi1:	DREX1 registers mapping
+ * @clk_regmap:		regmap for clock controller registers
+ * @lock:		protects curr_rate and frequency/voltage setting section
+ * @curr_rate:		current frequency
+ * @curr_volt:		current voltage
+ * @opp:		OPP table
+ * @opp_count:		number of 'opp' elements
+ * @timings_arr_size:	number of 'timings' elements
+ * @timing_row:		values for timing row register, for each OPP
+ * @timing_data:	values for timing data register, for each OPP
+ * @timing_power:	balues for timing power register, for each OPP
+ * @timings:		DDR memory timings, from device tree
+ * @min_tck:		DDR memory minimum timing values, from device tree
+ * @bypass_timing_row:	value for timing row register for bypass timings
+ * @bypass_timing_data:	value for timing data register for bypass timings
+ * @bypass_timing_power:	value for timing power register for bypass
+ *				timings
+ * @vdd_mif:		Memory interface regulator
+ * @fout_spll:		clock: SPLL
+ * @fout_bpll:		clock: BPLL
+ * @mout_spll:		clock: mux SPLL
+ * @mout_bpll:		clock: mux BPLL
+ * @mout_mclk_cdrex:	clock: mux mclk_cdrex
+ * @mout_mx_mspll_ccore:	clock: mux mx_mspll_ccore
+ * @counter:		devfreq events
+ * @num_counters:	number of 'counter' elements
+ * @last_overflow_ts:	time (in ns) of last overflow of each DREX
+ * @load:		utilization in percents
+ * @total:		total time between devfreq events
+ * @in_irq_mode:	whether running in interrupt mode (true)
+ *			or polling (false)
+ *
+ * The main structure for the Dynamic Memory Controller which covers clocks,
+ * memory regions, HW information, parameters and current operating mode.
+ */
+struct exynos5_dmc {
+	struct device *dev;
+	struct devfreq *df;
+	struct devfreq_simple_ondemand_data gov_data;
+	void __iomem *base_drexi0;
+	void __iomem *base_drexi1;
+	struct regmap *clk_regmap;
+	/* Protects curr_rate and frequency/voltage setting section */
+	struct mutex lock;
+	unsigned long curr_rate;
+	unsigned long curr_volt;
+	struct dmc_opp_table *opp;
+	int opp_count;
+	u32 timings_arr_size;
+	u32 *timing_row;
+	u32 *timing_data;
+	u32 *timing_power;
+	const struct lpddr3_timings *timings;
+	const struct lpddr3_min_tck *min_tck;
+	u32 bypass_timing_row;
+	u32 bypass_timing_data;
+	u32 bypass_timing_power;
+	struct regulator *vdd_mif;
+	struct clk *fout_spll;
+	struct clk *fout_bpll;
+	struct clk *mout_spll;
+	struct clk *mout_bpll;
+	struct clk *mout_mclk_cdrex;
+	struct clk *mout_mx_mspll_ccore;
+	struct devfreq_event_dev **counter;
+	int num_counters;
+	u64 last_overflow_ts[2];
+	unsigned long load;
+	unsigned long total;
+	bool in_irq_mode;
+};
+
+#define TIMING_FIELD(t_name, t_bit_beg, t_bit_end) \
+	{ .name = t_name, .bit_beg = t_bit_beg, .bit_end = t_bit_end }
+
+#define TIMING_VAL2REG(timing, t_val)			\
+({							\
+		u32 __val;				\
+		__val = (t_val) << (timing)->bit_beg;	\
+		__val;					\
+})
+
+struct timing_reg {
+	char *name;
+	int bit_beg;
+	int bit_end;
+	unsigned int val;
+};
+
+static const struct timing_reg timing_row_reg_fields[] = {
+	TIMING_FIELD("tRFC", 24, 31),
+	TIMING_FIELD("tRRD", 20, 23),
+	TIMING_FIELD("tRP", 16, 19),
+	TIMING_FIELD("tRCD", 12, 15),
+	TIMING_FIELD("tRC", 6, 11),
+	TIMING_FIELD("tRAS", 0, 5),
+};
+
+static const struct timing_reg timing_data_reg_fields[] = {
+	TIMING_FIELD("tWTR", 28, 31),
+	TIMING_FIELD("tWR", 24, 27),
+	TIMING_FIELD("tRTP", 20, 23),
+	TIMING_FIELD("tW2W-C2C", 14, 14),
+	TIMING_FIELD("tR2R-C2C", 12, 12),
+	TIMING_FIELD("WL", 8, 11),
+	TIMING_FIELD("tDQSCK", 4, 7),
+	TIMING_FIELD("RL", 0, 3),
+};
+
+static const struct timing_reg timing_power_reg_fields[] = {
+	TIMING_FIELD("tFAW", 26, 31),
+	TIMING_FIELD("tXSR", 16, 25),
+	TIMING_FIELD("tXP", 8, 15),
+	TIMING_FIELD("tCKE", 4, 7),
+	TIMING_FIELD("tMRD", 0, 3),
+};
+
+#define TIMING_COUNT (ARRAY_SIZE(timing_row_reg_fields) + \
+		      ARRAY_SIZE(timing_data_reg_fields) + \
+		      ARRAY_SIZE(timing_power_reg_fields))
+
+static int exynos5_counters_set_event(struct exynos5_dmc *dmc)
+{
+	int i, ret;
+
+	for (i = 0; i < dmc->num_counters; i++) {
+		if (!dmc->counter[i])
+			continue;
+		ret = devfreq_event_set_event(dmc->counter[i]);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+static int exynos5_counters_enable_edev(struct exynos5_dmc *dmc)
+{
+	int i, ret;
+
+	for (i = 0; i < dmc->num_counters; i++) {
+		if (!dmc->counter[i])
+			continue;
+		ret = devfreq_event_enable_edev(dmc->counter[i]);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+static int exynos5_counters_disable_edev(struct exynos5_dmc *dmc)
+{
+	int i, ret;
+
+	for (i = 0; i < dmc->num_counters; i++) {
+		if (!dmc->counter[i])
+			continue;
+		ret = devfreq_event_disable_edev(dmc->counter[i]);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+/**
+ * find_target_freq_idx() - Finds requested frequency in local DMC configuration
+ * @dmc:	device for which the information is checked
+ * @target_rate:	requested frequency in KHz
+ *
+ * Seeks in the local DMC driver structure for the requested frequency value
+ * and returns index or error value.
+ */
+static int find_target_freq_idx(struct exynos5_dmc *dmc,
+				unsigned long target_rate)
+{
+	int i;
+
+	for (i = dmc->opp_count - 1; i >= 0; i--)
+		if (dmc->opp[i].freq_hz <= target_rate)
+			return i;
+
+	return -EINVAL;
+}
+
+/**
+ * exynos5_switch_timing_regs() - Changes bank register set for DRAM timings
+ * @dmc:	device for which the new settings is going to be applied
+ * @set:	boolean variable passing set value
+ *
+ * Changes the register set, which holds timing parameters.
+ * There is two register sets: 0 and 1. The register set 0
+ * is used in normal operation when the clock is provided from main PLL.
+ * The bank register set 1 is used when the main PLL frequency is going to be
+ * changed and the clock is taken from alternative, stable source.
+ * This function switches between these banks according to the
+ * currently used clock source.
+ */
+static int exynos5_switch_timing_regs(struct exynos5_dmc *dmc, bool set)
+{
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(dmc->clk_regmap, CDREX_LPDDR3PHY_CON3, &reg);
+	if (ret)
+		return ret;
+
+	if (set)
+		reg |= EXYNOS5_TIMING_SET_SWI;
+	else
+		reg &= ~EXYNOS5_TIMING_SET_SWI;
+
+	regmap_write(dmc->clk_regmap, CDREX_LPDDR3PHY_CON3, reg);
+
+	return 0;
+}
+
+/**
+ * exynos5_init_freq_table() - Initialized PM OPP framework
+ * @dmc:	DMC device for which the frequencies are used for OPP init
+ * @profile:	devfreq device's profile
+ *
+ * Populate the devfreq device's OPP table based on current frequency, voltage.
+ */
+static int exynos5_init_freq_table(struct exynos5_dmc *dmc,
+				   struct devfreq_dev_profile *profile)
+{
+	struct device *dev = dmc->dev;
+	int i, ret;
+	int idx;
+	unsigned long freq;
+
+	ret = devm_pm_opp_of_add_table(dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to get OPP table\n");
+		return ret;
+	}
+
+	dmc->opp_count = dev_pm_opp_get_opp_count(dev);
+
+	dmc->opp = devm_kmalloc_array(dev, dmc->opp_count,
+				      sizeof(struct dmc_opp_table), GFP_KERNEL);
+	if (!dmc->opp)
+		return -ENOMEM;
+
+	idx = dmc->opp_count - 1;
+	for (i = 0, freq = ULONG_MAX; i < dmc->opp_count; i++, freq--) {
+		struct dev_pm_opp *opp;
+
+		opp = dev_pm_opp_find_freq_floor(dev, &freq);
+		if (IS_ERR(opp))
+			return PTR_ERR(opp);
+
+		dmc->opp[idx - i].freq_hz = freq;
+		dmc->opp[idx - i].volt_uv = dev_pm_opp_get_voltage(opp);
+
+		dev_pm_opp_put(opp);
+	}
+
+	return 0;
+}
+
+/**
+ * exynos5_set_bypass_dram_timings() - Low-level changes of the DRAM timings
+ * @dmc:	device for which the new settings is going to be applied
+ *
+ * Low-level function for changing timings for DRAM memory clocking from
+ * 'bypass' clock source (fixed frequency @400MHz).
+ * It uses timing bank registers set 1.
+ */
+static void exynos5_set_bypass_dram_timings(struct exynos5_dmc *dmc)
+{
+	writel(EXYNOS5_AREF_NORMAL,
+	       dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGAREF);
+
+	writel(dmc->bypass_timing_row,
+	       dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGROW1);
+	writel(dmc->bypass_timing_row,
+	       dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGROW1);
+	writel(dmc->bypass_timing_data,
+	       dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGDATA1);
+	writel(dmc->bypass_timing_data,
+	       dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGDATA1);
+	writel(dmc->bypass_timing_power,
+	       dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGPOWER1);
+	writel(dmc->bypass_timing_power,
+	       dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGPOWER1);
+}
+
+/**
+ * exynos5_dram_change_timings() - Low-level changes of the DRAM final timings
+ * @dmc:	device for which the new settings is going to be applied
+ * @target_rate:	target frequency of the DMC
+ *
+ * Low-level function for changing timings for DRAM memory operating from main
+ * clock source (BPLL), which can have different frequencies. Thus, each
+ * frequency must have corresponding timings register values in order to keep
+ * the needed delays.
+ * It uses timing bank registers set 0.
+ */
+static int exynos5_dram_change_timings(struct exynos5_dmc *dmc,
+				       unsigned long target_rate)
+{
+	int idx;
+
+	for (idx = dmc->opp_count - 1; idx >= 0; idx--)
+		if (dmc->opp[idx].freq_hz <= target_rate)
+			break;
+
+	if (idx < 0)
+		return -EINVAL;
+
+	writel(EXYNOS5_AREF_NORMAL,
+	       dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGAREF);
+
+	writel(dmc->timing_row[idx],
+	       dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGROW0);
+	writel(dmc->timing_row[idx],
+	       dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGROW0);
+	writel(dmc->timing_data[idx],
+	       dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGDATA0);
+	writel(dmc->timing_data[idx],
+	       dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGDATA0);
+	writel(dmc->timing_power[idx],
+	       dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGPOWER0);
+	writel(dmc->timing_power[idx],
+	       dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGPOWER0);
+
+	return 0;
+}
+
+/**
+ * exynos5_dmc_align_target_voltage() - Sets the final voltage for the DMC
+ * @dmc:	device for which it is going to be set
+ * @target_volt:	new voltage which is chosen to be final
+ *
+ * Function tries to align voltage to the safe level for 'normal' mode.
+ * It checks the need of higher voltage and changes the value. The target
+ * voltage might be lower that currently set and still the system will be
+ * stable.
+ */
+static int exynos5_dmc_align_target_voltage(struct exynos5_dmc *dmc,
+					    unsigned long target_volt)
+{
+	int ret = 0;
+
+	if (dmc->curr_volt <= target_volt)
+		return 0;
+
+	ret = regulator_set_voltage(dmc->vdd_mif, target_volt,
+				    target_volt);
+	if (!ret)
+		dmc->curr_volt = target_volt;
+
+	return ret;
+}
+
+/**
+ * exynos5_dmc_align_bypass_voltage() - Sets the voltage for the DMC
+ * @dmc:	device for which it is going to be set
+ * @target_volt:	new voltage which is chosen to be final
+ *
+ * Function tries to align voltage to the safe level for the 'bypass' mode.
+ * It checks the need of higher voltage and changes the value.
+ * The target voltage must not be less than currently needed, because
+ * for current frequency the device might become unstable.
+ */
+static int exynos5_dmc_align_bypass_voltage(struct exynos5_dmc *dmc,
+					    unsigned long target_volt)
+{
+	int ret = 0;
+
+	if (dmc->curr_volt >= target_volt)
+		return 0;
+
+	ret = regulator_set_voltage(dmc->vdd_mif, target_volt,
+				    target_volt);
+	if (!ret)
+		dmc->curr_volt = target_volt;
+
+	return ret;
+}
+
+/**
+ * exynos5_dmc_align_bypass_dram_timings() - Chooses and sets DRAM timings
+ * @dmc:	device for which it is going to be set
+ * @target_rate:	new frequency which is chosen to be final
+ *
+ * Function changes the DRAM timings for the temporary 'bypass' mode.
+ */
+static int exynos5_dmc_align_bypass_dram_timings(struct exynos5_dmc *dmc,
+						 unsigned long target_rate)
+{
+	int idx = find_target_freq_idx(dmc, target_rate);
+
+	if (idx < 0)
+		return -EINVAL;
+
+	exynos5_set_bypass_dram_timings(dmc);
+
+	return 0;
+}
+
+/**
+ * exynos5_dmc_switch_to_bypass_configuration() - Switching to temporary clock
+ * @dmc:	DMC device for which the switching is going to happen
+ * @target_rate:	new frequency which is going to be set as a final
+ * @target_volt:	new voltage which is going to be set as a final
+ *
+ * Function configures DMC and clocks for operating in temporary 'bypass' mode.
+ * This mode is used only temporary but if required, changes voltage and timings
+ * for DRAM chips. It switches the main clock to stable clock source for the
+ * period of the main PLL reconfiguration.
+ */
+static int
+exynos5_dmc_switch_to_bypass_configuration(struct exynos5_dmc *dmc,
+					   unsigned long target_rate,
+					   unsigned long target_volt)
+{
+	int ret;
+
+	/*
+	 * Having higher voltage for a particular frequency does not harm
+	 * the chip. Use it for the temporary frequency change when one
+	 * voltage manipulation might be avoided.
+	 */
+	ret = exynos5_dmc_align_bypass_voltage(dmc, target_volt);
+	if (ret)
+		return ret;
+
+	/*
+	 * Longer delays for DRAM does not cause crash, the opposite does.
+	 */
+	ret = exynos5_dmc_align_bypass_dram_timings(dmc, target_rate);
+	if (ret)
+		return ret;
+
+	/*
+	 * Delays are long enough, so use them for the new coming clock.
+	 */
+	ret = exynos5_switch_timing_regs(dmc, USE_MX_MSPLL_TIMINGS);
+
+	return ret;
+}
+
+/**
+ * exynos5_dmc_change_freq_and_volt() - Changes voltage and frequency of the DMC
+ * using safe procedure
+ * @dmc:	device for which the frequency is going to be changed
+ * @target_rate:	requested new frequency
+ * @target_volt:	requested voltage which corresponds to the new frequency
+ *
+ * The DMC frequency change procedure requires a few steps.
+ * The main requirement is to change the clock source in the clk mux
+ * for the time of main clock PLL locking. The assumption is that the
+ * alternative clock source set as parent is stable.
+ * The second parent's clock frequency is fixed to 400MHz, it is named 'bypass'
+ * clock. This requires alignment in DRAM timing parameters for the new
+ * T-period. There is two bank sets for keeping DRAM
+ * timings: set 0 and set 1. The set 0 is used when main clock source is
+ * chosen. The 2nd set of regs is used for 'bypass' clock. Switching between
+ * the two bank sets is part of the process.
+ * The voltage must also be aligned to the minimum required level. There is
+ * this intermediate step with switching to 'bypass' parent clock source.
+ * if the old voltage is lower, it requires an increase of the voltage level.
+ * The complexity of the voltage manipulation is hidden in low level function.
+ * In this function there is last alignment of the voltage level at the end.
+ */
+static int
+exynos5_dmc_change_freq_and_volt(struct exynos5_dmc *dmc,
+				 unsigned long target_rate,
+				 unsigned long target_volt)
+{
+	int ret;
+
+	ret = exynos5_dmc_switch_to_bypass_configuration(dmc, target_rate,
+							 target_volt);
+	if (ret)
+		return ret;
+
+	/*
+	 * Voltage is set at least to a level needed for this frequency,
+	 * so switching clock source is safe now.
+	 */
+	clk_prepare_enable(dmc->fout_spll);
+	clk_prepare_enable(dmc->mout_spll);
+	clk_prepare_enable(dmc->mout_mx_mspll_ccore);
+
+	ret = clk_set_parent(dmc->mout_mclk_cdrex, dmc->mout_mx_mspll_ccore);
+	if (ret)
+		goto disable_clocks;
+
+	/*
+	 * We are safe to increase the timings for current bypass frequency.
+	 * Thanks to this the settings will be ready for the upcoming clock
+	 * source change.
+	 */
+	exynos5_dram_change_timings(dmc, target_rate);
+
+	clk_set_rate(dmc->fout_bpll, target_rate);
+
+	ret = exynos5_switch_timing_regs(dmc, USE_BPLL_TIMINGS);
+	if (ret)
+		goto disable_clocks;
+
+	ret = clk_set_parent(dmc->mout_mclk_cdrex, dmc->mout_bpll);
+	if (ret)
+		goto disable_clocks;
+
+	/*
+	 * Make sure if the voltage is not from 'bypass' settings and align to
+	 * the right level for power efficiency.
+	 */
+	ret = exynos5_dmc_align_target_voltage(dmc, target_volt);
+
+disable_clocks:
+	clk_disable_unprepare(dmc->mout_mx_mspll_ccore);
+	clk_disable_unprepare(dmc->mout_spll);
+	clk_disable_unprepare(dmc->fout_spll);
+
+	return ret;
+}
+
+/**
+ * exynos5_dmc_get_volt_freq() - Gets the frequency and voltage from the OPP
+ * table.
+ * @dmc:	device for which the frequency is going to be changed
+ * @freq:       requested frequency in KHz
+ * @target_rate:	returned frequency which is the same or lower than
+ *			requested
+ * @target_volt:	returned voltage which corresponds to the returned
+ *			frequency
+ * @flags:	devfreq flags provided for this frequency change request
+ *
+ * Function gets requested frequency and checks OPP framework for needed
+ * frequency and voltage. It populates the values 'target_rate' and
+ * 'target_volt' or returns error value when OPP framework fails.
+ */
+static int exynos5_dmc_get_volt_freq(struct exynos5_dmc *dmc,
+				     unsigned long *freq,
+				     unsigned long *target_rate,
+				     unsigned long *target_volt, u32 flags)
+{
+	struct dev_pm_opp *opp;
+
+	opp = devfreq_recommended_opp(dmc->dev, freq, flags);
+	if (IS_ERR(opp))
+		return PTR_ERR(opp);
+
+	*target_rate = dev_pm_opp_get_freq(opp);
+	*target_volt = dev_pm_opp_get_voltage(opp);
+	dev_pm_opp_put(opp);
+
+	return 0;
+}
+
+/**
+ * exynos5_dmc_target() - Function responsible for changing frequency of DMC
+ * @dev:	device for which the frequency is going to be changed
+ * @freq:	requested frequency in KHz
+ * @flags:	flags provided for this frequency change request
+ *
+ * An entry function provided to the devfreq framework which provides frequency
+ * change of the DMC. The function gets the possible rate from OPP table based
+ * on requested frequency. It calls the next function responsible for the
+ * frequency and voltage change. In case of failure, does not set 'curr_rate'
+ * and returns error value to the framework.
+ */
+static int exynos5_dmc_target(struct device *dev, unsigned long *freq,
+			      u32 flags)
+{
+	struct exynos5_dmc *dmc = dev_get_drvdata(dev);
+	unsigned long target_rate = 0;
+	unsigned long target_volt = 0;
+	int ret;
+
+	ret = exynos5_dmc_get_volt_freq(dmc, freq, &target_rate, &target_volt,
+					flags);
+
+	if (ret)
+		return ret;
+
+	if (target_rate == dmc->curr_rate)
+		return 0;
+
+	mutex_lock(&dmc->lock);
+
+	ret = exynos5_dmc_change_freq_and_volt(dmc, target_rate, target_volt);
+
+	if (ret) {
+		mutex_unlock(&dmc->lock);
+		return ret;
+	}
+
+	dmc->curr_rate = target_rate;
+
+	mutex_unlock(&dmc->lock);
+	return 0;
+}
+
+/**
+ * exynos5_counters_get() - Gets the performance counters values.
+ * @dmc:	device for which the counters are going to be checked
+ * @load_count:	variable which is populated with counter value
+ * @total_count:	variable which is used as 'wall clock' reference
+ *
+ * Function which provides performance counters values. It sums up counters for
+ * two DMC channels. The 'total_count' is used as a reference and max value.
+ * The ratio 'load_count/total_count' shows the busy percentage [0%, 100%].
+ */
+static int exynos5_counters_get(struct exynos5_dmc *dmc,
+				unsigned long *load_count,
+				unsigned long *total_count)
+{
+	unsigned long total = 0;
+	struct devfreq_event_data event;
+	int ret, i;
+
+	*load_count = 0;
+
+	/* Take into account only read+write counters, but stop all */
+	for (i = 0; i < dmc->num_counters; i++) {
+		if (!dmc->counter[i])
+			continue;
+
+		ret = devfreq_event_get_event(dmc->counter[i], &event);
+		if (ret < 0)
+			return ret;
+
+		*load_count += event.load_count;
+
+		if (total < event.total_count)
+			total = event.total_count;
+	}
+
+	*total_count = total;
+
+	return 0;
+}
+
+/**
+ * exynos5_dmc_start_perf_events() - Setup and start performance event counters
+ * @dmc:	device for which the counters are going to be checked
+ * @beg_value:	initial value for the counter
+ *
+ * Function which enables needed counters, interrupts and sets initial values
+ * then starts the counters.
+ */
+static void exynos5_dmc_start_perf_events(struct exynos5_dmc *dmc,
+					  u32 beg_value)
+{
+	/* Enable interrupts for counter 2 */
+	writel(PERF_CNT2, dmc->base_drexi0 + DREX_INTENS_PPC);
+	writel(PERF_CNT2, dmc->base_drexi1 + DREX_INTENS_PPC);
+
+	/* Enable counter 2 and CCNT  */
+	writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi0 + DREX_CNTENS_PPC);
+	writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi1 + DREX_CNTENS_PPC);
+
+	/* Clear overflow flag for all counters */
+	writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi0 + DREX_FLAG_PPC);
+	writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi1 + DREX_FLAG_PPC);
+
+	/* Reset all counters */
+	writel(CC_RESET | PPC_COUNTER_RESET, dmc->base_drexi0 + DREX_PMNC_PPC);
+	writel(CC_RESET | PPC_COUNTER_RESET, dmc->base_drexi1 + DREX_PMNC_PPC);
+
+	/*
+	 * Set start value for the counters, the number of samples that
+	 * will be gathered is calculated as: 0xffffffff - beg_value
+	 */
+	writel(beg_value, dmc->base_drexi0 + DREX_PMCNT2_PPC);
+	writel(beg_value, dmc->base_drexi1 + DREX_PMCNT2_PPC);
+
+	/* Start all counters */
+	writel(PPC_ENABLE, dmc->base_drexi0 + DREX_PMNC_PPC);
+	writel(PPC_ENABLE, dmc->base_drexi1 + DREX_PMNC_PPC);
+}
+
+/**
+ * exynos5_dmc_perf_events_calc() - Calculate utilization
+ * @dmc:	device for which the counters are going to be checked
+ * @diff_ts:	time between last interrupt and current one
+ *
+ * Function which calculates needed utilization for the devfreq governor.
+ * It prepares values for 'busy_time' and 'total_time' based on elapsed time
+ * between interrupts, which approximates utilization.
+ */
+static void exynos5_dmc_perf_events_calc(struct exynos5_dmc *dmc, u64 diff_ts)
+{
+	/*
+	 * This is a simple algorithm for managing traffic on DMC.
+	 * When there is almost no load the counters overflow every 4s,
+	 * no mater the DMC frequency.
+	 * The high load might be approximated using linear function.
+	 * Knowing that, simple calculation can provide 'busy_time' and
+	 * 'total_time' to the devfreq governor which picks up target
+	 * frequency.
+	 * We want a fast ramp up and slow decay in frequency change function.
+	 */
+	if (diff_ts < PERF_EVENT_UP_DOWN_THRESHOLD) {
+		/*
+		 * Set higher utilization for the simple_ondemand governor.
+		 * The governor should increase the frequency of the DMC.
+		 */
+		dmc->load = 70;
+		dmc->total = 100;
+	} else {
+		/*
+		 * Set low utilization for the simple_ondemand governor.
+		 * The governor should decrease the frequency of the DMC.
+		 */
+		dmc->load = 35;
+		dmc->total = 100;
+	}
+
+	dev_dbg(dmc->dev, "diff_ts=%llu\n", diff_ts);
+}
+
+/**
+ * exynos5_dmc_perf_events_check() - Checks the status of the counters
+ * @dmc:	device for which the counters are going to be checked
+ *
+ * Function which is called from threaded IRQ to check the counters state
+ * and to call approximation for the needed utilization.
+ */
+static void exynos5_dmc_perf_events_check(struct exynos5_dmc *dmc)
+{
+	u32 val;
+	u64 diff_ts, ts;
+
+	ts = ktime_get_ns();
+
+	/* Stop all counters */
+	writel(0, dmc->base_drexi0 + DREX_PMNC_PPC);
+	writel(0, dmc->base_drexi1 + DREX_PMNC_PPC);
+
+	/* Check the source in interrupt flag registers (which channel) */
+	val = readl(dmc->base_drexi0 + DREX_FLAG_PPC);
+	if (val) {
+		diff_ts = ts - dmc->last_overflow_ts[0];
+		dmc->last_overflow_ts[0] = ts;
+		dev_dbg(dmc->dev, "drex0 0xE050 val= 0x%08x\n",  val);
+	} else {
+		val = readl(dmc->base_drexi1 + DREX_FLAG_PPC);
+		diff_ts = ts - dmc->last_overflow_ts[1];
+		dmc->last_overflow_ts[1] = ts;
+		dev_dbg(dmc->dev, "drex1 0xE050 val= 0x%08x\n",  val);
+	}
+
+	exynos5_dmc_perf_events_calc(dmc, diff_ts);
+
+	exynos5_dmc_start_perf_events(dmc, PERF_COUNTER_START_VALUE);
+}
+
+/**
+ * exynos5_dmc_enable_perf_events() - Enable performance events
+ * @dmc:	device for which the counters are going to be checked
+ *
+ * Function which is setup needed environment and enables counters.
+ */
+static void exynos5_dmc_enable_perf_events(struct exynos5_dmc *dmc)
+{
+	u64 ts;
+
+	/* Enable Performance Event Clock */
+	writel(PEREV_CLK_EN, dmc->base_drexi0 + DREX_PPCCLKCON);
+	writel(PEREV_CLK_EN, dmc->base_drexi1 + DREX_PPCCLKCON);
+
+	/* Select read transfers as performance event2 */
+	writel(READ_TRANSFER_CH0, dmc->base_drexi0 + DREX_PEREV2CONFIG);
+	writel(READ_TRANSFER_CH1, dmc->base_drexi1 + DREX_PEREV2CONFIG);
+
+	ts = ktime_get_ns();
+	dmc->last_overflow_ts[0] = ts;
+	dmc->last_overflow_ts[1] = ts;
+
+	/* Devfreq shouldn't be faster than initialization, play safe though. */
+	dmc->load = 99;
+	dmc->total = 100;
+}
+
+/**
+ * exynos5_dmc_disable_perf_events() - Disable performance events
+ * @dmc:	device for which the counters are going to be checked
+ *
+ * Function which stops, disables performance event counters and interrupts.
+ */
+static void exynos5_dmc_disable_perf_events(struct exynos5_dmc *dmc)
+{
+	/* Stop all counters */
+	writel(0, dmc->base_drexi0 + DREX_PMNC_PPC);
+	writel(0, dmc->base_drexi1 + DREX_PMNC_PPC);
+
+	/* Disable interrupts for counter 2 */
+	writel(PERF_CNT2, dmc->base_drexi0 + DREX_INTENC_PPC);
+	writel(PERF_CNT2, dmc->base_drexi1 + DREX_INTENC_PPC);
+
+	/* Disable counter 2 and CCNT  */
+	writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi0 + DREX_CNTENC_PPC);
+	writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi1 + DREX_CNTENC_PPC);
+
+	/* Clear overflow flag for all counters */
+	writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi0 + DREX_FLAG_PPC);
+	writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi1 + DREX_FLAG_PPC);
+}
+
+/**
+ * exynos5_dmc_get_status() - Read current DMC performance statistics.
+ * @dev:	device for which the statistics are requested
+ * @stat:	structure which has statistic fields
+ *
+ * Function reads the DMC performance counters and calculates 'busy_time'
+ * and 'total_time'. To protect from overflow, the values are shifted right
+ * by 10. After read out the counters are setup to count again.
+ */
+static int exynos5_dmc_get_status(struct device *dev,
+				  struct devfreq_dev_status *stat)
+{
+	struct exynos5_dmc *dmc = dev_get_drvdata(dev);
+	unsigned long load, total;
+	int ret;
+
+	if (dmc->in_irq_mode) {
+		mutex_lock(&dmc->lock);
+		stat->current_frequency = dmc->curr_rate;
+		mutex_unlock(&dmc->lock);
+
+		stat->busy_time = dmc->load;
+		stat->total_time = dmc->total;
+	} else {
+		ret = exynos5_counters_get(dmc, &load, &total);
+		if (ret < 0)
+			return -EINVAL;
+
+		/* To protect from overflow, divide by 1024 */
+		stat->busy_time = load >> 10;
+		stat->total_time = total >> 10;
+
+		ret = exynos5_counters_set_event(dmc);
+		if (ret < 0) {
+			dev_err(dev, "could not set event counter\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * exynos5_dmc_get_cur_freq() - Function returns current DMC frequency
+ * @dev:	device for which the framework checks operating frequency
+ * @freq:	returned frequency value
+ *
+ * It returns the currently used frequency of the DMC. The real operating
+ * frequency might be lower when the clock source value could not be divided
+ * to the requested value.
+ */
+static int exynos5_dmc_get_cur_freq(struct device *dev, unsigned long *freq)
+{
+	struct exynos5_dmc *dmc = dev_get_drvdata(dev);
+
+	mutex_lock(&dmc->lock);
+	*freq = dmc->curr_rate;
+	mutex_unlock(&dmc->lock);
+
+	return 0;
+}
+
+/*
+ * exynos5_dmc_df_profile - Devfreq governor's profile structure
+ *
+ * It provides to the devfreq framework needed functions and polling period.
+ */
+static struct devfreq_dev_profile exynos5_dmc_df_profile = {
+	.timer = DEVFREQ_TIMER_DELAYED,
+	.target = exynos5_dmc_target,
+	.get_dev_status = exynos5_dmc_get_status,
+	.get_cur_freq = exynos5_dmc_get_cur_freq,
+};
+
+/**
+ * exynos5_dmc_align_init_freq() - Align initial frequency value
+ * @dmc:	device for which the frequency is going to be set
+ * @bootloader_init_freq:	initial frequency set by the bootloader in KHz
+ *
+ * The initial bootloader frequency, which is present during boot, might be
+ * different that supported frequency values in the driver. It is possible
+ * due to different PLL settings or used PLL as a source.
+ * This function provides the 'initial_freq' for the devfreq framework
+ * statistics engine which supports only registered values. Thus, some alignment
+ * must be made.
+ */
+static unsigned long
+exynos5_dmc_align_init_freq(struct exynos5_dmc *dmc,
+			    unsigned long bootloader_init_freq)
+{
+	unsigned long aligned_freq;
+	int idx;
+
+	idx = find_target_freq_idx(dmc, bootloader_init_freq);
+	if (idx >= 0)
+		aligned_freq = dmc->opp[idx].freq_hz;
+	else
+		aligned_freq = dmc->opp[dmc->opp_count - 1].freq_hz;
+
+	return aligned_freq;
+}
+
+/**
+ * create_timings_aligned() - Create register values and align with standard
+ * @dmc:	device for which the frequency is going to be set
+ * @reg_timing_row:	array to fill with values for timing row register
+ * @reg_timing_data:	array to fill with values for timing data register
+ * @reg_timing_power:	array to fill with values for timing power register
+ * @clk_period_ps:	the period of the clock, known as tCK
+ *
+ * The function calculates timings and creates a register value ready for
+ * a frequency transition. The register contains a few timings. They are
+ * shifted by a known offset. The timing value is calculated based on memory
+ * specyfication: minimal time required and minimal cycles required.
+ */
+static int create_timings_aligned(struct exynos5_dmc *dmc, u32 *reg_timing_row,
+				  u32 *reg_timing_data, u32 *reg_timing_power,
+				  u32 clk_period_ps)
+{
+	u32 val;
+	const struct timing_reg *reg;
+
+	if (clk_period_ps == 0)
+		return -EINVAL;
+
+	*reg_timing_row = 0;
+	*reg_timing_data = 0;
+	*reg_timing_power = 0;
+
+	val = dmc->timings->tRFC / clk_period_ps;
+	val += dmc->timings->tRFC % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tRFC);
+	reg = &timing_row_reg_fields[0];
+	*reg_timing_row |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tRRD / clk_period_ps;
+	val += dmc->timings->tRRD % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tRRD);
+	reg = &timing_row_reg_fields[1];
+	*reg_timing_row |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tRPab / clk_period_ps;
+	val += dmc->timings->tRPab % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tRPab);
+	reg = &timing_row_reg_fields[2];
+	*reg_timing_row |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tRCD / clk_period_ps;
+	val += dmc->timings->tRCD % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tRCD);
+	reg = &timing_row_reg_fields[3];
+	*reg_timing_row |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tRC / clk_period_ps;
+	val += dmc->timings->tRC % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tRC);
+	reg = &timing_row_reg_fields[4];
+	*reg_timing_row |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tRAS / clk_period_ps;
+	val += dmc->timings->tRAS % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tRAS);
+	reg = &timing_row_reg_fields[5];
+	*reg_timing_row |= TIMING_VAL2REG(reg, val);
+
+	/* data related timings */
+	val = dmc->timings->tWTR / clk_period_ps;
+	val += dmc->timings->tWTR % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tWTR);
+	reg = &timing_data_reg_fields[0];
+	*reg_timing_data |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tWR / clk_period_ps;
+	val += dmc->timings->tWR % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tWR);
+	reg = &timing_data_reg_fields[1];
+	*reg_timing_data |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tRTP / clk_period_ps;
+	val += dmc->timings->tRTP % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tRTP);
+	reg = &timing_data_reg_fields[2];
+	*reg_timing_data |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tW2W_C2C / clk_period_ps;
+	val += dmc->timings->tW2W_C2C % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tW2W_C2C);
+	reg = &timing_data_reg_fields[3];
+	*reg_timing_data |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tR2R_C2C / clk_period_ps;
+	val += dmc->timings->tR2R_C2C % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tR2R_C2C);
+	reg = &timing_data_reg_fields[4];
+	*reg_timing_data |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tWL / clk_period_ps;
+	val += dmc->timings->tWL % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tWL);
+	reg = &timing_data_reg_fields[5];
+	*reg_timing_data |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tDQSCK / clk_period_ps;
+	val += dmc->timings->tDQSCK % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tDQSCK);
+	reg = &timing_data_reg_fields[6];
+	*reg_timing_data |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tRL / clk_period_ps;
+	val += dmc->timings->tRL % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tRL);
+	reg = &timing_data_reg_fields[7];
+	*reg_timing_data |= TIMING_VAL2REG(reg, val);
+
+	/* power related timings */
+	val = dmc->timings->tFAW / clk_period_ps;
+	val += dmc->timings->tFAW % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tFAW);
+	reg = &timing_power_reg_fields[0];
+	*reg_timing_power |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tXSR / clk_period_ps;
+	val += dmc->timings->tXSR % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tXSR);
+	reg = &timing_power_reg_fields[1];
+	*reg_timing_power |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tXP / clk_period_ps;
+	val += dmc->timings->tXP % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tXP);
+	reg = &timing_power_reg_fields[2];
+	*reg_timing_power |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tCKE / clk_period_ps;
+	val += dmc->timings->tCKE % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tCKE);
+	reg = &timing_power_reg_fields[3];
+	*reg_timing_power |= TIMING_VAL2REG(reg, val);
+
+	val = dmc->timings->tMRD / clk_period_ps;
+	val += dmc->timings->tMRD % clk_period_ps ? 1 : 0;
+	val = max(val, dmc->min_tck->tMRD);
+	reg = &timing_power_reg_fields[4];
+	*reg_timing_power |= TIMING_VAL2REG(reg, val);
+
+	return 0;
+}
+
+/**
+ * of_get_dram_timings() - helper function for parsing DT settings for DRAM
+ * @dmc:        device for which the frequency is going to be set
+ *
+ * The function parses DT entries with DRAM information.
+ */
+static int of_get_dram_timings(struct exynos5_dmc *dmc)
+{
+	int ret = 0;
+	struct device *dev = dmc->dev;
+	int idx;
+	u32 freq_mhz, clk_period_ps;
+
+	struct device_node *np_ddr __free(device_node) =
+		of_parse_phandle(dev->of_node, "device-handle", 0);
+	if (!np_ddr) {
+		dev_warn(dev, "could not find 'device-handle' in DT\n");
+		return -EINVAL;
+	}
+
+	dmc->timing_row = devm_kmalloc_array(dev, TIMING_COUNT,
+					     sizeof(u32), GFP_KERNEL);
+	if (!dmc->timing_row)
+		return -ENOMEM;
+
+	dmc->timing_data = devm_kmalloc_array(dev, TIMING_COUNT,
+					      sizeof(u32), GFP_KERNEL);
+	if (!dmc->timing_data)
+		return -ENOMEM;
+
+	dmc->timing_power = devm_kmalloc_array(dev, TIMING_COUNT,
+					       sizeof(u32), GFP_KERNEL);
+	if (!dmc->timing_power)
+		return -ENOMEM;
+
+	dmc->timings = of_lpddr3_get_ddr_timings(np_ddr, dev,
+						 DDR_TYPE_LPDDR3,
+						 &dmc->timings_arr_size);
+	if (!dmc->timings) {
+		dev_warn(dev, "could not get timings from DT\n");
+		return -EINVAL;
+	}
+
+	dmc->min_tck = of_lpddr3_get_min_tck(np_ddr, dev);
+	if (!dmc->min_tck) {
+		dev_warn(dev, "could not get tck from DT\n");
+		return -EINVAL;
+	}
+
+	/* Sorted array of OPPs with frequency ascending */
+	for (idx = 0; idx < dmc->opp_count; idx++) {
+		freq_mhz = dmc->opp[idx].freq_hz / 1000000;
+		clk_period_ps = 1000000 / freq_mhz;
+
+		ret = create_timings_aligned(dmc, &dmc->timing_row[idx],
+					     &dmc->timing_data[idx],
+					     &dmc->timing_power[idx],
+					     clk_period_ps);
+	}
+
+
+	/* Take the highest frequency's timings as 'bypass' */
+	dmc->bypass_timing_row = dmc->timing_row[idx - 1];
+	dmc->bypass_timing_data = dmc->timing_data[idx - 1];
+	dmc->bypass_timing_power = dmc->timing_power[idx - 1];
+
+	return ret;
+}
+
+/**
+ * exynos5_dmc_init_clks() - Initialize clocks needed for DMC operation.
+ * @dmc:	DMC structure containing needed fields
+ *
+ * Get the needed clocks defined in DT device, enable and set the right parents.
+ * Read current frequency and initialize the initial rate for governor.
+ */
+static int exynos5_dmc_init_clks(struct exynos5_dmc *dmc)
+{
+	int ret;
+	struct device *dev = dmc->dev;
+	unsigned long target_volt = 0;
+	unsigned long target_rate = 0;
+	unsigned int tmp;
+
+	dmc->fout_spll = devm_clk_get(dev, "fout_spll");
+	if (IS_ERR(dmc->fout_spll))
+		return PTR_ERR(dmc->fout_spll);
+
+	dmc->fout_bpll = devm_clk_get(dev, "fout_bpll");
+	if (IS_ERR(dmc->fout_bpll))
+		return PTR_ERR(dmc->fout_bpll);
+
+	dmc->mout_mclk_cdrex = devm_clk_get(dev, "mout_mclk_cdrex");
+	if (IS_ERR(dmc->mout_mclk_cdrex))
+		return PTR_ERR(dmc->mout_mclk_cdrex);
+
+	dmc->mout_bpll = devm_clk_get(dev, "mout_bpll");
+	if (IS_ERR(dmc->mout_bpll))
+		return PTR_ERR(dmc->mout_bpll);
+
+	dmc->mout_mx_mspll_ccore = devm_clk_get(dev, "mout_mx_mspll_ccore");
+	if (IS_ERR(dmc->mout_mx_mspll_ccore))
+		return PTR_ERR(dmc->mout_mx_mspll_ccore);
+
+	dmc->mout_spll = devm_clk_get(dev, "ff_dout_spll2");
+	if (IS_ERR(dmc->mout_spll)) {
+		dmc->mout_spll = devm_clk_get(dev, "mout_sclk_spll");
+		if (IS_ERR(dmc->mout_spll))
+			return PTR_ERR(dmc->mout_spll);
+	}
+
+	/*
+	 * Convert frequency to KHz values and set it for the governor.
+	 */
+	dmc->curr_rate = clk_get_rate(dmc->mout_mclk_cdrex);
+	dmc->curr_rate = exynos5_dmc_align_init_freq(dmc, dmc->curr_rate);
+	exynos5_dmc_df_profile.initial_freq = dmc->curr_rate;
+
+	ret = exynos5_dmc_get_volt_freq(dmc, &dmc->curr_rate, &target_rate,
+					&target_volt, 0);
+	if (ret)
+		return ret;
+
+	dmc->curr_volt = target_volt;
+
+	ret = clk_set_parent(dmc->mout_mx_mspll_ccore, dmc->mout_spll);
+	if (ret)
+		return ret;
+
+	clk_prepare_enable(dmc->fout_bpll);
+	clk_prepare_enable(dmc->mout_bpll);
+
+	/*
+	 * Some bootloaders do not set clock routes correctly.
+	 * Stop one path in clocks to PHY.
+	 */
+	regmap_read(dmc->clk_regmap, CDREX_LPDDR3PHY_CLKM_SRC, &tmp);
+	tmp &= ~(BIT(1) | BIT(0));
+	regmap_write(dmc->clk_regmap, CDREX_LPDDR3PHY_CLKM_SRC, tmp);
+
+	return 0;
+}
+
+/**
+ * exynos5_performance_counters_init() - Initializes performance DMC's counters
+ * @dmc:	DMC for which it does the setup
+ *
+ * Initialization of performance counters in DMC for estimating usage.
+ * The counter's values are used for calculation of a memory bandwidth and based
+ * on that the governor changes the frequency.
+ * The counters are not used when the governor is GOVERNOR_USERSPACE.
+ */
+static int exynos5_performance_counters_init(struct exynos5_dmc *dmc)
+{
+	struct device *dev = dmc->dev;
+	int ret, i;
+
+	dmc->num_counters = devfreq_event_get_edev_count(dev, "devfreq-events");
+	if (dmc->num_counters < 0) {
+		dev_err(dev, "could not get devfreq-event counters\n");
+		return dmc->num_counters;
+	}
+
+	dmc->counter = devm_kcalloc(dev, dmc->num_counters,
+				    sizeof(*dmc->counter), GFP_KERNEL);
+	if (!dmc->counter)
+		return -ENOMEM;
+
+	for (i = 0; i < dmc->num_counters; i++) {
+		dmc->counter[i] =
+			devfreq_event_get_edev_by_phandle(dev, "devfreq-events", i);
+		if (IS_ERR_OR_NULL(dmc->counter[i]))
+			return -EPROBE_DEFER;
+	}
+
+	ret = exynos5_counters_enable_edev(dmc);
+	if (ret < 0) {
+		dev_err(dev, "could not enable event counter\n");
+		return ret;
+	}
+
+	ret = exynos5_counters_set_event(dmc);
+	if (ret < 0) {
+		exynos5_counters_disable_edev(dmc);
+		dev_err(dev, "could not set event counter\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * exynos5_dmc_set_pause_on_switching() - Controls a pause feature in DMC
+ * @dmc:	device which is used for changing this feature
+ *
+ * There is a need of pausing DREX DMC when divider or MUX in clock tree
+ * changes its configuration. In such situation access to the memory is blocked
+ * in DMC automatically. This feature is used when clock frequency change
+ * request appears and touches clock tree.
+ */
+static inline int exynos5_dmc_set_pause_on_switching(struct exynos5_dmc *dmc)
+{
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(dmc->clk_regmap, CDREX_PAUSE, &val);
+	if (ret)
+		return ret;
+
+	val |= 1UL;
+	regmap_write(dmc->clk_regmap, CDREX_PAUSE, val);
+
+	return 0;
+}
+
+static irqreturn_t dmc_irq_thread(int irq, void *priv)
+{
+	int res;
+	struct exynos5_dmc *dmc = priv;
+
+	mutex_lock(&dmc->df->lock);
+	exynos5_dmc_perf_events_check(dmc);
+	res = update_devfreq(dmc->df);
+	mutex_unlock(&dmc->df->lock);
+
+	if (res)
+		dev_warn(dmc->dev, "devfreq failed with %d\n", res);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * exynos5_dmc_probe() - Probe function for the DMC driver
+ * @pdev:	platform device for which the driver is going to be initialized
+ *
+ * Initialize basic components: clocks, regulators, performance counters, etc.
+ * Read out product version and based on the information setup
+ * internal structures for the controller (frequency and voltage) and for DRAM
+ * memory parameters: timings for each operating frequency.
+ * Register new devfreq device for controlling DVFS of the DMC.
+ */
+static int exynos5_dmc_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct exynos5_dmc *dmc;
+	int irq[2];
+
+	dmc = devm_kzalloc(dev, sizeof(*dmc), GFP_KERNEL);
+	if (!dmc)
+		return -ENOMEM;
+
+	mutex_init(&dmc->lock);
+
+	dmc->dev = dev;
+	platform_set_drvdata(pdev, dmc);
+
+	dmc->base_drexi0 = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(dmc->base_drexi0))
+		return PTR_ERR(dmc->base_drexi0);
+
+	dmc->base_drexi1 = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(dmc->base_drexi1))
+		return PTR_ERR(dmc->base_drexi1);
+
+	dmc->clk_regmap = syscon_regmap_lookup_by_phandle(np,
+							  "samsung,syscon-clk");
+	if (IS_ERR(dmc->clk_regmap))
+		return PTR_ERR(dmc->clk_regmap);
+
+	ret = exynos5_init_freq_table(dmc, &exynos5_dmc_df_profile);
+	if (ret) {
+		dev_warn(dev, "couldn't initialize frequency settings\n");
+		return ret;
+	}
+
+	dmc->vdd_mif = devm_regulator_get(dev, "vdd");
+	if (IS_ERR(dmc->vdd_mif)) {
+		ret = PTR_ERR(dmc->vdd_mif);
+		return ret;
+	}
+
+	ret = exynos5_dmc_init_clks(dmc);
+	if (ret)
+		return ret;
+
+	ret = of_get_dram_timings(dmc);
+	if (ret) {
+		dev_warn(dev, "couldn't initialize timings settings\n");
+		goto remove_clocks;
+	}
+
+	ret = exynos5_dmc_set_pause_on_switching(dmc);
+	if (ret) {
+		dev_warn(dev, "couldn't get access to PAUSE register\n");
+		goto remove_clocks;
+	}
+
+	/* There is two modes in which the driver works: polling or IRQ */
+	irq[0] = platform_get_irq_byname(pdev, "drex_0");
+	irq[1] = platform_get_irq_byname(pdev, "drex_1");
+	if (irq[0] > 0 && irq[1] > 0 && irqmode) {
+		ret = devm_request_threaded_irq(dev, irq[0], NULL,
+						dmc_irq_thread, IRQF_ONESHOT,
+						dev_name(dev), dmc);
+		if (ret) {
+			dev_err(dev, "couldn't grab IRQ\n");
+			goto remove_clocks;
+		}
+
+		ret = devm_request_threaded_irq(dev, irq[1], NULL,
+						dmc_irq_thread, IRQF_ONESHOT,
+						dev_name(dev), dmc);
+		if (ret) {
+			dev_err(dev, "couldn't grab IRQ\n");
+			goto remove_clocks;
+		}
+
+		/*
+		 * Setup default thresholds for the devfreq governor.
+		 * The values are chosen based on experiments.
+		 */
+		dmc->gov_data.upthreshold = 55;
+		dmc->gov_data.downdifferential = 5;
+
+		exynos5_dmc_enable_perf_events(dmc);
+
+		dmc->in_irq_mode = 1;
+	} else {
+		ret = exynos5_performance_counters_init(dmc);
+		if (ret) {
+			dev_warn(dev, "couldn't probe performance counters\n");
+			goto remove_clocks;
+		}
+
+		/*
+		 * Setup default thresholds for the devfreq governor.
+		 * The values are chosen based on experiments.
+		 */
+		dmc->gov_data.upthreshold = 10;
+		dmc->gov_data.downdifferential = 5;
+
+		exynos5_dmc_df_profile.polling_ms = 100;
+	}
+
+	dmc->df = devm_devfreq_add_device(dev, &exynos5_dmc_df_profile,
+					  DEVFREQ_GOV_SIMPLE_ONDEMAND,
+					  &dmc->gov_data);
+
+	if (IS_ERR(dmc->df)) {
+		ret = PTR_ERR(dmc->df);
+		goto err_devfreq_add;
+	}
+
+	if (dmc->in_irq_mode)
+		exynos5_dmc_start_perf_events(dmc, PERF_COUNTER_START_VALUE);
+
+	dev_info(dev, "DMC initialized, in irq mode: %d\n", dmc->in_irq_mode);
+
+	return 0;
+
+err_devfreq_add:
+	if (dmc->in_irq_mode)
+		exynos5_dmc_disable_perf_events(dmc);
+	else
+		exynos5_counters_disable_edev(dmc);
+remove_clocks:
+	clk_disable_unprepare(dmc->mout_bpll);
+	clk_disable_unprepare(dmc->fout_bpll);
+
+	return ret;
+}
+
+/**
+ * exynos5_dmc_remove() - Remove function for the platform device
+ * @pdev:	platform device which is going to be removed
+ *
+ * The function relies on 'devm' framework function which automatically
+ * clean the device's resources. It just calls explicitly disable function for
+ * the performance counters.
+ */
+static void exynos5_dmc_remove(struct platform_device *pdev)
+{
+	struct exynos5_dmc *dmc = dev_get_drvdata(&pdev->dev);
+
+	if (dmc->in_irq_mode)
+		exynos5_dmc_disable_perf_events(dmc);
+	else
+		exynos5_counters_disable_edev(dmc);
+
+	clk_disable_unprepare(dmc->mout_bpll);
+	clk_disable_unprepare(dmc->fout_bpll);
+}
+
+static const struct of_device_id exynos5_dmc_of_match[] = {
+	{ .compatible = "samsung,exynos5422-dmc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, exynos5_dmc_of_match);
+
+static struct platform_driver exynos5_dmc_platdrv = {
+	.probe	= exynos5_dmc_probe,
+	.remove = exynos5_dmc_remove,
+	.driver = {
+		.name	= "exynos5-dmc",
+		.of_match_table = exynos5_dmc_of_match,
+	},
+};
+module_platform_driver(exynos5_dmc_platdrv);
+MODULE_DESCRIPTION("Driver for Exynos5422 Dynamic Memory Controller dynamic frequency and voltage change");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Lukasz Luba");