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
  ...

1 files changed, 985 insertions, 0 deletions

diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
new file mode 100644
index 000000000..401aac6a9
--- /dev/null
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -0,0 +1,985 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * A devfreq driver for NVIDIA Tegra SoCs
+ *
+ * Copyright (c) 2014 NVIDIA CORPORATION. All rights reserved.
+ * Copyright (C) 2014 Google, Inc
+ */
+
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/devfreq.h>
+#include <linux/devfreq-governor.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/reset.h>
+#include <linux/workqueue.h>
+
+#include <soc/tegra/fuse.h>
+
+#define ACTMON_GLB_STATUS					0x0
+#define ACTMON_GLB_PERIOD_CTRL					0x4
+
+#define ACTMON_DEV_CTRL						0x0
+#define ACTMON_DEV_CTRL_K_VAL_SHIFT				10
+#define ACTMON_DEV_CTRL_ENB_PERIODIC				BIT(18)
+#define ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN			BIT(20)
+#define ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN			BIT(21)
+#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT	23
+#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT	26
+#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN		BIT(29)
+#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN		BIT(30)
+#define ACTMON_DEV_CTRL_ENB					BIT(31)
+
+#define ACTMON_DEV_CTRL_STOP					0x00000000
+
+#define ACTMON_DEV_UPPER_WMARK					0x4
+#define ACTMON_DEV_LOWER_WMARK					0x8
+#define ACTMON_DEV_INIT_AVG					0xc
+#define ACTMON_DEV_AVG_UPPER_WMARK				0x10
+#define ACTMON_DEV_AVG_LOWER_WMARK				0x14
+#define ACTMON_DEV_COUNT_WEIGHT					0x18
+#define ACTMON_DEV_AVG_COUNT					0x20
+#define ACTMON_DEV_INTR_STATUS					0x24
+
+#define ACTMON_INTR_STATUS_CLEAR				0xffffffff
+
+#define ACTMON_DEV_INTR_CONSECUTIVE_UPPER			BIT(31)
+#define ACTMON_DEV_INTR_CONSECUTIVE_LOWER			BIT(30)
+
+#define ACTMON_ABOVE_WMARK_WINDOW				1
+#define ACTMON_BELOW_WMARK_WINDOW				3
+#define ACTMON_BOOST_FREQ_STEP					16000
+
+/*
+ * ACTMON_AVERAGE_WINDOW_LOG2: default value for @DEV_CTRL_K_VAL, which
+ * translates to 2 ^ (K_VAL + 1). ex: 2 ^ (6 + 1) = 128
+ */
+#define ACTMON_AVERAGE_WINDOW_LOG2			6
+#define ACTMON_SAMPLING_PERIOD				12 /* ms */
+#define ACTMON_DEFAULT_AVG_BAND				6  /* 1/10 of % */
+
+#define KHZ							1000
+
+#define KHZ_MAX						(ULONG_MAX / KHZ)
+
+/* Assume that the bus is saturated if the utilization is 25% */
+#define BUS_SATURATION_RATIO					25
+
+/**
+ * struct tegra_devfreq_device_config - configuration specific to an ACTMON
+ * device
+ *
+ * Coefficients and thresholds are percentages unless otherwise noted
+ */
+struct tegra_devfreq_device_config {
+	u32		offset;
+	u32		irq_mask;
+
+	/* Factors applied to boost_freq every consecutive watermark breach */
+	unsigned int	boost_up_coeff;
+	unsigned int	boost_down_coeff;
+
+	/* Define the watermark bounds when applied to the current avg */
+	unsigned int	boost_up_threshold;
+	unsigned int	boost_down_threshold;
+
+	/*
+	 * Threshold of activity (cycles translated to kHz) below which the
+	 * CPU frequency isn't to be taken into account. This is to avoid
+	 * increasing the EMC frequency when the CPU is very busy but not
+	 * accessing the bus often.
+	 */
+	u32		avg_dependency_threshold;
+};
+
+enum tegra_actmon_device {
+	MCALL = 0,
+	MCCPU,
+};
+
+static const struct tegra_devfreq_device_config tegra124_device_configs[] = {
+	{
+		/* MCALL: All memory accesses (including from the CPUs) */
+		.offset = 0x1c0,
+		.irq_mask = 1 << 26,
+		.boost_up_coeff = 200,
+		.boost_down_coeff = 50,
+		.boost_up_threshold = 60,
+		.boost_down_threshold = 40,
+	},
+	{
+		/* MCCPU: memory accesses from the CPUs */
+		.offset = 0x200,
+		.irq_mask = 1 << 25,
+		.boost_up_coeff = 800,
+		.boost_down_coeff = 40,
+		.boost_up_threshold = 27,
+		.boost_down_threshold = 10,
+		.avg_dependency_threshold = 16000, /* 16MHz in kHz units */
+	},
+};
+
+static const struct tegra_devfreq_device_config tegra30_device_configs[] = {
+	{
+		/* MCALL: All memory accesses (including from the CPUs) */
+		.offset = 0x1c0,
+		.irq_mask = 1 << 26,
+		.boost_up_coeff = 200,
+		.boost_down_coeff = 50,
+		.boost_up_threshold = 20,
+		.boost_down_threshold = 10,
+	},
+	{
+		/* MCCPU: memory accesses from the CPUs */
+		.offset = 0x200,
+		.irq_mask = 1 << 25,
+		.boost_up_coeff = 800,
+		.boost_down_coeff = 40,
+		.boost_up_threshold = 27,
+		.boost_down_threshold = 10,
+		.avg_dependency_threshold = 16000, /* 16MHz in kHz units */
+	},
+};
+
+/**
+ * struct tegra_devfreq_device - state specific to an ACTMON device
+ *
+ * Frequencies are in kHz.
+ */
+struct tegra_devfreq_device {
+	const struct tegra_devfreq_device_config *config;
+	void __iomem *regs;
+
+	/* Average event count sampled in the last interrupt */
+	u32 avg_count;
+
+	/*
+	 * Extra frequency to increase the target by due to consecutive
+	 * watermark breaches.
+	 */
+	unsigned long boost_freq;
+
+	/* Optimal frequency calculated from the stats for this device */
+	unsigned long target_freq;
+};
+
+struct tegra_devfreq_soc_data {
+	const struct tegra_devfreq_device_config *configs;
+	/* Weight value for count measurements */
+	unsigned int count_weight;
+};
+
+struct tegra_devfreq {
+	struct devfreq		*devfreq;
+
+	struct reset_control	*reset;
+	struct clk		*clock;
+	void __iomem		*regs;
+
+	struct clk		*emc_clock;
+	unsigned long		max_freq;
+	unsigned long		cur_freq;
+	struct notifier_block	clk_rate_change_nb;
+
+	struct delayed_work	cpufreq_update_work;
+	struct notifier_block	cpu_rate_change_nb;
+
+	struct tegra_devfreq_device devices[2];
+
+	unsigned int		irq;
+
+	bool			started;
+
+	const struct tegra_devfreq_soc_data *soc;
+};
+
+struct tegra_actmon_emc_ratio {
+	unsigned long cpu_freq;
+	unsigned long emc_freq;
+};
+
+static const struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
+	{ 1400000,    KHZ_MAX },
+	{ 1200000,    750000 },
+	{ 1100000,    600000 },
+	{ 1000000,    500000 },
+	{  800000,    375000 },
+	{  500000,    200000 },
+	{  250000,    100000 },
+};
+
+static u32 actmon_readl(struct tegra_devfreq *tegra, u32 offset)
+{
+	return readl_relaxed(tegra->regs + offset);
+}
+
+static void actmon_writel(struct tegra_devfreq *tegra, u32 val, u32 offset)
+{
+	writel_relaxed(val, tegra->regs + offset);
+}
+
+static u32 device_readl(struct tegra_devfreq_device *dev, u32 offset)
+{
+	return readl_relaxed(dev->regs + offset);
+}
+
+static void device_writel(struct tegra_devfreq_device *dev, u32 val,
+			  u32 offset)
+{
+	writel_relaxed(val, dev->regs + offset);
+}
+
+static unsigned long do_percent(unsigned long long val, unsigned int pct)
+{
+	val = val * pct;
+	do_div(val, 100);
+
+	/*
+	 * High freq + high boosting percent + large polling interval are
+	 * resulting in integer overflow when watermarks are calculated.
+	 */
+	return min_t(u64, val, U32_MAX);
+}
+
+static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
+					   struct tegra_devfreq_device *dev)
+{
+	u32 avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
+	u32 band = avg_band_freq * tegra->devfreq->profile->polling_ms;
+	u32 avg;
+
+	avg = min(dev->avg_count, U32_MAX - band);
+	device_writel(dev, avg + band, ACTMON_DEV_AVG_UPPER_WMARK);
+
+	avg = max(dev->avg_count, band);
+	device_writel(dev, avg - band, ACTMON_DEV_AVG_LOWER_WMARK);
+}
+
+static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
+				       struct tegra_devfreq_device *dev)
+{
+	u32 val = tegra->cur_freq * tegra->devfreq->profile->polling_ms;
+
+	device_writel(dev, do_percent(val, dev->config->boost_up_threshold),
+		      ACTMON_DEV_UPPER_WMARK);
+
+	device_writel(dev, do_percent(val, dev->config->boost_down_threshold),
+		      ACTMON_DEV_LOWER_WMARK);
+}
+
+static void actmon_isr_device(struct tegra_devfreq *tegra,
+			      struct tegra_devfreq_device *dev)
+{
+	u32 intr_status, dev_ctrl;
+
+	dev->avg_count = device_readl(dev, ACTMON_DEV_AVG_COUNT);
+	tegra_devfreq_update_avg_wmark(tegra, dev);
+
+	intr_status = device_readl(dev, ACTMON_DEV_INTR_STATUS);
+	dev_ctrl = device_readl(dev, ACTMON_DEV_CTRL);
+
+	if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_UPPER) {
+		/*
+		 * new_boost = min(old_boost * up_coef + step, max_freq)
+		 */
+		dev->boost_freq = do_percent(dev->boost_freq,
+					     dev->config->boost_up_coeff);
+		dev->boost_freq += ACTMON_BOOST_FREQ_STEP;
+
+		dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+
+		if (dev->boost_freq >= tegra->max_freq) {
+			dev_ctrl &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+			dev->boost_freq = tegra->max_freq;
+		}
+	} else if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) {
+		/*
+		 * new_boost = old_boost * down_coef
+		 * or 0 if (old_boost * down_coef < step / 2)
+		 */
+		dev->boost_freq = do_percent(dev->boost_freq,
+					     dev->config->boost_down_coeff);
+
+		dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+
+		if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> 1)) {
+			dev_ctrl &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
+			dev->boost_freq = 0;
+		}
+	}
+
+	device_writel(dev, dev_ctrl, ACTMON_DEV_CTRL);
+
+	device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
+}
+
+static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
+					    unsigned long cpu_freq)
+{
+	unsigned int i;
+	const struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios;
+
+	for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, ratio++)
+		if (cpu_freq >= ratio->cpu_freq)
+			return min(ratio->emc_freq, tegra->max_freq);
+
+	return 0;
+}
+
+static unsigned long actmon_device_target_freq(struct tegra_devfreq *tegra,
+					       struct tegra_devfreq_device *dev)
+{
+	unsigned int avg_sustain_coef;
+	unsigned long target_freq;
+
+	target_freq = dev->avg_count / tegra->devfreq->profile->polling_ms;
+	avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
+	target_freq = do_percent(target_freq, avg_sustain_coef);
+
+	return target_freq;
+}
+
+static void actmon_update_target(struct tegra_devfreq *tegra,
+				 struct tegra_devfreq_device *dev)
+{
+	unsigned long cpu_freq = 0;
+	unsigned long static_cpu_emc_freq = 0;
+
+	dev->target_freq = actmon_device_target_freq(tegra, dev);
+
+	if (dev->config->avg_dependency_threshold &&
+	    dev->config->avg_dependency_threshold <= dev->target_freq) {
+		cpu_freq = cpufreq_quick_get(0);
+		static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
+
+		dev->target_freq += dev->boost_freq;
+		dev->target_freq = max(dev->target_freq, static_cpu_emc_freq);
+	} else {
+		dev->target_freq += dev->boost_freq;
+	}
+}
+
+static irqreturn_t actmon_thread_isr(int irq, void *data)
+{
+	struct tegra_devfreq *tegra = data;
+	bool handled = false;
+	unsigned int i;
+	u32 val;
+
+	mutex_lock(&tegra->devfreq->lock);
+
+	val = actmon_readl(tegra, ACTMON_GLB_STATUS);
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		if (val & tegra->devices[i].config->irq_mask) {
+			actmon_isr_device(tegra, tegra->devices + i);
+			handled = true;
+		}
+	}
+
+	if (handled)
+		update_devfreq(tegra->devfreq);
+
+	mutex_unlock(&tegra->devfreq->lock);
+
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int tegra_actmon_clk_notify_cb(struct notifier_block *nb,
+				      unsigned long action, void *ptr)
+{
+	struct clk_notifier_data *data = ptr;
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *dev;
+	unsigned int i;
+
+	if (action != POST_RATE_CHANGE)
+		return NOTIFY_OK;
+
+	tegra = container_of(nb, struct tegra_devfreq, clk_rate_change_nb);
+
+	tegra->cur_freq = data->new_rate / KHZ;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		dev = &tegra->devices[i];
+
+		tegra_devfreq_update_wmark(tegra, dev);
+	}
+
+	return NOTIFY_OK;
+}
+
+static void tegra_actmon_delayed_update(struct work_struct *work)
+{
+	struct tegra_devfreq *tegra = container_of(work, struct tegra_devfreq,
+						   cpufreq_update_work.work);
+
+	mutex_lock(&tegra->devfreq->lock);
+	update_devfreq(tegra->devfreq);
+	mutex_unlock(&tegra->devfreq->lock);
+}
+
+static unsigned long
+tegra_actmon_cpufreq_contribution(struct tegra_devfreq *tegra,
+				  unsigned int cpu_freq)
+{
+	struct tegra_devfreq_device *actmon_dev = &tegra->devices[MCCPU];
+	unsigned long static_cpu_emc_freq, dev_freq;
+
+	dev_freq = actmon_device_target_freq(tegra, actmon_dev);
+
+	/* check whether CPU's freq is taken into account at all */
+	if (dev_freq < actmon_dev->config->avg_dependency_threshold)
+		return 0;
+
+	static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
+
+	if (dev_freq + actmon_dev->boost_freq >= static_cpu_emc_freq)
+		return 0;
+
+	return static_cpu_emc_freq;
+}
+
+static int tegra_actmon_cpu_notify_cb(struct notifier_block *nb,
+				      unsigned long action, void *ptr)
+{
+	struct cpufreq_freqs *freqs = ptr;
+	struct tegra_devfreq *tegra;
+	unsigned long old, new, delay;
+
+	if (action != CPUFREQ_POSTCHANGE)
+		return NOTIFY_OK;
+
+	tegra = container_of(nb, struct tegra_devfreq, cpu_rate_change_nb);
+
+	/*
+	 * Quickly check whether CPU frequency should be taken into account
+	 * at all, without blocking CPUFreq's core.
+	 */
+	if (mutex_trylock(&tegra->devfreq->lock)) {
+		old = tegra_actmon_cpufreq_contribution(tegra, freqs->old);
+		new = tegra_actmon_cpufreq_contribution(tegra, freqs->new);
+		mutex_unlock(&tegra->devfreq->lock);
+
+		/*
+		 * If CPU's frequency shouldn't be taken into account at
+		 * the moment, then there is no need to update the devfreq's
+		 * state because ISR will re-check CPU's frequency on the
+		 * next interrupt.
+		 */
+		if (old == new)
+			return NOTIFY_OK;
+	}
+
+	/*
+	 * CPUFreq driver should support CPUFREQ_ASYNC_NOTIFICATION in order
+	 * to allow asynchronous notifications. This means we can't block
+	 * here for too long, otherwise CPUFreq's core will complain with a
+	 * warning splat.
+	 */
+	delay = msecs_to_jiffies(ACTMON_SAMPLING_PERIOD);
+	schedule_delayed_work(&tegra->cpufreq_update_work, delay);
+
+	return NOTIFY_OK;
+}
+
+static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
+					  struct tegra_devfreq_device *dev)
+{
+	u32 val = 0;
+
+	/* reset boosting on governor's restart */
+	dev->boost_freq = 0;
+
+	dev->target_freq = tegra->cur_freq;
+
+	dev->avg_count = tegra->cur_freq * tegra->devfreq->profile->polling_ms;
+	device_writel(dev, dev->avg_count, ACTMON_DEV_INIT_AVG);
+
+	tegra_devfreq_update_avg_wmark(tegra, dev);
+	tegra_devfreq_update_wmark(tegra, dev);
+
+	device_writel(dev, tegra->soc->count_weight, ACTMON_DEV_COUNT_WEIGHT);
+	device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
+
+	val |= ACTMON_DEV_CTRL_ENB_PERIODIC;
+	val |= (ACTMON_AVERAGE_WINDOW_LOG2 - 1)
+		<< ACTMON_DEV_CTRL_K_VAL_SHIFT;
+	val |= (ACTMON_BELOW_WMARK_WINDOW - 1)
+		<< ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT;
+	val |= (ACTMON_ABOVE_WMARK_WINDOW - 1)
+		<< ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT;
+	val |= ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN;
+	val |= ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN;
+	val |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+	val |= ACTMON_DEV_CTRL_ENB;
+
+	device_writel(dev, val, ACTMON_DEV_CTRL);
+}
+
+static void tegra_actmon_stop_devices(struct tegra_devfreq *tegra)
+{
+	struct tegra_devfreq_device *dev = tegra->devices;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++, dev++) {
+		device_writel(dev, ACTMON_DEV_CTRL_STOP, ACTMON_DEV_CTRL);
+		device_writel(dev, ACTMON_INTR_STATUS_CLEAR,
+			      ACTMON_DEV_INTR_STATUS);
+	}
+}
+
+static int tegra_actmon_resume(struct tegra_devfreq *tegra)
+{
+	unsigned int i;
+	int err;
+
+	if (!tegra->devfreq->profile->polling_ms || !tegra->started)
+		return 0;
+
+	actmon_writel(tegra, tegra->devfreq->profile->polling_ms - 1,
+		      ACTMON_GLB_PERIOD_CTRL);
+
+	/*
+	 * CLK notifications are needed in order to reconfigure the upper
+	 * consecutive watermark in accordance to the actual clock rate
+	 * to avoid unnecessary upper interrupts.
+	 */
+	err = clk_notifier_register(tegra->emc_clock,
+				    &tegra->clk_rate_change_nb);
+	if (err) {
+		dev_err(tegra->devfreq->dev.parent,
+			"Failed to register rate change notifier\n");
+		return err;
+	}
+
+	tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
+		tegra_actmon_configure_device(tegra, &tegra->devices[i]);
+
+	/*
+	 * We are estimating CPU's memory bandwidth requirement based on
+	 * amount of memory accesses and system's load, judging by CPU's
+	 * frequency. We also don't want to receive events about CPU's
+	 * frequency transaction when governor is stopped, hence notifier
+	 * is registered dynamically.
+	 */
+	err = cpufreq_register_notifier(&tegra->cpu_rate_change_nb,
+					CPUFREQ_TRANSITION_NOTIFIER);
+	if (err) {
+		dev_err(tegra->devfreq->dev.parent,
+			"Failed to register rate change notifier: %d\n", err);
+		goto err_stop;
+	}
+
+	enable_irq(tegra->irq);
+
+	return 0;
+
+err_stop:
+	tegra_actmon_stop_devices(tegra);
+
+	clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
+
+	return err;
+}
+
+static int tegra_actmon_start(struct tegra_devfreq *tegra)
+{
+	int ret = 0;
+
+	if (!tegra->started) {
+		tegra->started = true;
+
+		ret = tegra_actmon_resume(tegra);
+		if (ret)
+			tegra->started = false;
+	}
+
+	return ret;
+}
+
+static void tegra_actmon_pause(struct tegra_devfreq *tegra)
+{
+	if (!tegra->devfreq->profile->polling_ms || !tegra->started)
+		return;
+
+	disable_irq(tegra->irq);
+
+	cpufreq_unregister_notifier(&tegra->cpu_rate_change_nb,
+				    CPUFREQ_TRANSITION_NOTIFIER);
+
+	cancel_delayed_work_sync(&tegra->cpufreq_update_work);
+
+	tegra_actmon_stop_devices(tegra);
+
+	clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
+}
+
+static void tegra_actmon_stop(struct tegra_devfreq *tegra)
+{
+	tegra_actmon_pause(tegra);
+	tegra->started = false;
+}
+
+static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
+				u32 flags)
+{
+	struct dev_pm_opp *opp;
+	int ret;
+
+	opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(opp)) {
+		dev_err(dev, "Failed to find opp for %lu Hz\n", *freq);
+		return PTR_ERR(opp);
+	}
+
+	ret = dev_pm_opp_set_opp(dev, opp);
+	dev_pm_opp_put(opp);
+
+	return ret;
+}
+
+static int tegra_devfreq_get_dev_status(struct device *dev,
+					struct devfreq_dev_status *stat)
+{
+	struct tegra_devfreq *tegra = dev_get_drvdata(dev);
+	struct tegra_devfreq_device *actmon_dev;
+	unsigned long cur_freq;
+
+	cur_freq = READ_ONCE(tegra->cur_freq);
+
+	/* To be used by the tegra governor */
+	stat->private_data = tegra;
+
+	/* The below are to be used by the other governors */
+	stat->current_frequency = cur_freq * KHZ;
+
+	actmon_dev = &tegra->devices[MCALL];
+
+	/* Number of cycles spent on memory access */
+	stat->busy_time = device_readl(actmon_dev, ACTMON_DEV_AVG_COUNT);
+
+	/* The bus can be considered to be saturated way before 100% */
+	stat->busy_time *= 100 / BUS_SATURATION_RATIO;
+
+	/* Number of cycles in a sampling period */
+	stat->total_time = tegra->devfreq->profile->polling_ms * cur_freq;
+
+	stat->busy_time = min(stat->busy_time, stat->total_time);
+
+	return 0;
+}
+
+static struct devfreq_dev_profile tegra_devfreq_profile = {
+	.polling_ms	= ACTMON_SAMPLING_PERIOD,
+	.target		= tegra_devfreq_target,
+	.get_dev_status	= tegra_devfreq_get_dev_status,
+	.is_cooling_device = true,
+};
+
+static int tegra_governor_get_target(struct devfreq *devfreq,
+				     unsigned long *freq)
+{
+	struct devfreq_dev_status *stat;
+	struct tegra_devfreq *tegra;
+	struct tegra_devfreq_device *dev;
+	unsigned long target_freq = 0;
+	unsigned int i;
+	int err;
+
+	err = devfreq_update_stats(devfreq);
+	if (err)
+		return err;
+
+	stat = &devfreq->last_status;
+
+	tegra = stat->private_data;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		dev = &tegra->devices[i];
+
+		actmon_update_target(tegra, dev);
+
+		target_freq = max(target_freq, dev->target_freq);
+	}
+
+	/*
+	 * tegra-devfreq driver operates with KHz units, while OPP table
+	 * entries use Hz units. Hence we need to convert the units for the
+	 * devfreq core.
+	 */
+	*freq = target_freq * KHZ;
+
+	return 0;
+}
+
+static int tegra_governor_event_handler(struct devfreq *devfreq,
+					unsigned int event, void *data)
+{
+	struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
+	unsigned int *new_delay = data;
+	int ret = 0;
+
+	/*
+	 * Couple devfreq-device with the governor early because it is
+	 * needed at the moment of governor's start (used by ISR).
+	 */
+	tegra->devfreq = devfreq;
+
+	switch (event) {
+	case DEVFREQ_GOV_START:
+		devfreq_monitor_start(devfreq);
+		ret = tegra_actmon_start(tegra);
+		break;
+
+	case DEVFREQ_GOV_STOP:
+		tegra_actmon_stop(tegra);
+		devfreq_monitor_stop(devfreq);
+		break;
+
+	case DEVFREQ_GOV_UPDATE_INTERVAL:
+		/*
+		 * ACTMON hardware supports up to 256 milliseconds for the
+		 * sampling period.
+		 */
+		if (*new_delay > 256) {
+			ret = -EINVAL;
+			break;
+		}
+
+		tegra_actmon_pause(tegra);
+		devfreq_update_interval(devfreq, new_delay);
+		ret = tegra_actmon_resume(tegra);
+		break;
+
+	case DEVFREQ_GOV_SUSPEND:
+		tegra_actmon_stop(tegra);
+		devfreq_monitor_suspend(devfreq);
+		break;
+
+	case DEVFREQ_GOV_RESUME:
+		devfreq_monitor_resume(devfreq);
+		ret = tegra_actmon_start(tegra);
+		break;
+	}
+
+	return ret;
+}
+
+static struct devfreq_governor tegra_devfreq_governor = {
+	.name = "tegra_actmon",
+	.attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL,
+	.flags = DEVFREQ_GOV_FLAG_IMMUTABLE
+		| DEVFREQ_GOV_FLAG_IRQ_DRIVEN,
+	.get_target_freq = tegra_governor_get_target,
+	.event_handler = tegra_governor_event_handler,
+};
+
+static void devm_tegra_devfreq_deinit_hw(void *data)
+{
+	struct tegra_devfreq *tegra = data;
+
+	reset_control_reset(tegra->reset);
+	clk_disable_unprepare(tegra->clock);
+}
+
+static int devm_tegra_devfreq_init_hw(struct device *dev,
+				      struct tegra_devfreq *tegra)
+{
+	int err;
+
+	err = clk_prepare_enable(tegra->clock);
+	if (err) {
+		dev_err(dev, "Failed to prepare and enable ACTMON clock\n");
+		return err;
+	}
+
+	err = devm_add_action_or_reset(dev, devm_tegra_devfreq_deinit_hw,
+				       tegra);
+	if (err)
+		return err;
+
+	err = reset_control_reset(tegra->reset);
+	if (err) {
+		dev_err(dev, "Failed to reset hardware: %d\n", err);
+		return err;
+	}
+
+	return err;
+}
+
+static int tegra_devfreq_config_clks_nop(struct device *dev,
+					 struct opp_table *opp_table,
+					 struct dev_pm_opp *opp, void *data,
+					 bool scaling_down)
+{
+	/* We want to skip clk configuration via dev_pm_opp_set_opp() */
+	return 0;
+}
+
+static int tegra_devfreq_probe(struct platform_device *pdev)
+{
+	u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
+	struct tegra_devfreq_device *dev;
+	struct tegra_devfreq *tegra;
+	struct devfreq *devfreq;
+	unsigned int i;
+	long rate;
+	int err;
+	const char *clk_names[] = { "actmon", NULL };
+	struct dev_pm_opp_config config = {
+		.supported_hw = &hw_version,
+		.supported_hw_count = 1,
+		.clk_names = clk_names,
+		.config_clks = tegra_devfreq_config_clks_nop,
+	};
+
+	tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
+	if (!tegra)
+		return -ENOMEM;
+
+	tegra->soc = of_device_get_match_data(&pdev->dev);
+
+	tegra->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(tegra->regs))
+		return PTR_ERR(tegra->regs);
+
+	tegra->reset = devm_reset_control_get(&pdev->dev, "actmon");
+	if (IS_ERR(tegra->reset)) {
+		dev_err(&pdev->dev, "Failed to get reset\n");
+		return PTR_ERR(tegra->reset);
+	}
+
+	tegra->clock = devm_clk_get(&pdev->dev, "actmon");
+	if (IS_ERR(tegra->clock)) {
+		dev_err(&pdev->dev, "Failed to get actmon clock\n");
+		return PTR_ERR(tegra->clock);
+	}
+
+	tegra->emc_clock = devm_clk_get(&pdev->dev, "emc");
+	if (IS_ERR(tegra->emc_clock))
+		return dev_err_probe(&pdev->dev, PTR_ERR(tegra->emc_clock),
+				     "Failed to get emc clock\n");
+
+	err = platform_get_irq(pdev, 0);
+	if (err < 0)
+		return err;
+
+	tegra->irq = err;
+
+	irq_set_status_flags(tegra->irq, IRQ_NOAUTOEN);
+
+	err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
+					actmon_thread_isr, IRQF_ONESHOT,
+					"tegra-devfreq", tegra);
+	if (err) {
+		dev_err(&pdev->dev, "Interrupt request failed: %d\n", err);
+		return err;
+	}
+
+	err = devm_pm_opp_set_config(&pdev->dev, &config);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to set OPP config: %d\n", err);
+		return err;
+	}
+
+	err = devm_pm_opp_of_add_table_indexed(&pdev->dev, 0);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to add OPP table: %d\n", err);
+		return err;
+	}
+
+	err = devm_tegra_devfreq_init_hw(&pdev->dev, tegra);
+	if (err)
+		return err;
+
+	rate = clk_round_rate(tegra->emc_clock, ULONG_MAX);
+	if (rate <= 0) {
+		dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", rate);
+		return rate ?: -EINVAL;
+	}
+
+	tegra->max_freq = rate / KHZ;
+
+	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
+		dev = tegra->devices + i;
+		dev->config = tegra->soc->configs + i;
+		dev->regs = tegra->regs + dev->config->offset;
+	}
+
+	platform_set_drvdata(pdev, tegra);
+
+	tegra->clk_rate_change_nb.notifier_call = tegra_actmon_clk_notify_cb;
+	tegra->cpu_rate_change_nb.notifier_call = tegra_actmon_cpu_notify_cb;
+
+	INIT_DELAYED_WORK(&tegra->cpufreq_update_work,
+			  tegra_actmon_delayed_update);
+
+	err = devm_devfreq_add_governor(&pdev->dev, &tegra_devfreq_governor);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to add governor: %d\n", err);
+		return err;
+	}
+
+	tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
+
+	devfreq = devm_devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
+					  "tegra_actmon", NULL);
+	if (IS_ERR(devfreq)) {
+		dev_err(&pdev->dev, "Failed to add device: %pe\n", devfreq);
+		return PTR_ERR(devfreq);
+	}
+
+	return 0;
+}
+
+/*
+ * The activity counter is incremented every 256 memory transactions. However,
+ * the number of clock cycles required for each transaction varies across
+ * different SoC generations. For instance, a single transaction takes 2 EMC
+ * clocks on Tegra30, 1 EMC clock on Tegra114, and 4 EMC clocks on Tegra124.
+ */
+static const struct tegra_devfreq_soc_data tegra124_soc = {
+	.configs = tegra124_device_configs,
+	.count_weight = 4 * 256,
+};
+
+static const struct tegra_devfreq_soc_data tegra114_soc = {
+	.configs = tegra124_device_configs,
+	.count_weight = 256,
+};
+
+static const struct tegra_devfreq_soc_data tegra30_soc = {
+	.configs = tegra30_device_configs,
+	.count_weight = 2 * 256,
+};
+
+static const struct of_device_id tegra_devfreq_of_match[] = {
+	{ .compatible = "nvidia,tegra30-actmon",  .data = &tegra30_soc, },
+	{ .compatible = "nvidia,tegra114-actmon", .data = &tegra114_soc, },
+	{ .compatible = "nvidia,tegra124-actmon", .data = &tegra124_soc, },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, tegra_devfreq_of_match);
+
+static struct platform_driver tegra_devfreq_driver = {
+	.probe	= tegra_devfreq_probe,
+	.driver = {
+		.name = "tegra-devfreq",
+		.of_match_table = tegra_devfreq_of_match,
+	},
+};
+module_platform_driver(tegra_devfreq_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Tegra devfreq driver");
+MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>");