Initial import

1 files changed, 835 insertions, 0 deletions

diff --git a/drivers/thermal/intel_powerclamp.c b/drivers/thermal/intel_powerclamp.c
new file mode 100644
index 000000000..725718e97
--- /dev/null
+++ b/drivers/thermal/intel_powerclamp.c
@@ -0,0 +1,835 @@
+/*
+ * intel_powerclamp.c - package c-state idle injection
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ *
+ * Authors:
+ *     Arjan van de Ven <arjan@linux.intel.com>
+ *     Jacob Pan <jacob.jun.pan@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *
+ *	TODO:
+ *           1. better handle wakeup from external interrupts, currently a fixed
+ *              compensation is added to clamping duration when excessive amount
+ *              of wakeups are observed during idle time. the reason is that in
+ *              case of external interrupts without need for ack, clamping down
+ *              cpu in non-irq context does not reduce irq. for majority of the
+ *              cases, clamping down cpu does help reduce irq as well, we should
+ *              be able to differenciate the two cases and give a quantitative
+ *              solution for the irqs that we can control. perhaps based on
+ *              get_cpu_iowait_time_us()
+ *
+ *	     2. synchronization with other hw blocks
+ *
+ *
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/thermal.h>
+#include <linux/slab.h>
+#include <linux/tick.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/sched/rt.h>
+
+#include <asm/nmi.h>
+#include <asm/msr.h>
+#include <asm/mwait.h>
+#include <asm/cpu_device_id.h>
+#include <asm/idle.h>
+#include <asm/hardirq.h>
+
+#define MAX_TARGET_RATIO (50U)
+/* For each undisturbed clamping period (no extra wake ups during idle time),
+ * we increment the confidence counter for the given target ratio.
+ * CONFIDENCE_OK defines the level where runtime calibration results are
+ * valid.
+ */
+#define CONFIDENCE_OK (3)
+/* Default idle injection duration, driver adjust sleep time to meet target
+ * idle ratio. Similar to frequency modulation.
+ */
+#define DEFAULT_DURATION_JIFFIES (6)
+
+static unsigned int target_mwait;
+static struct dentry *debug_dir;
+
+/* user selected target */
+static unsigned int set_target_ratio;
+static unsigned int current_ratio;
+static bool should_skip;
+static bool reduce_irq;
+static atomic_t idle_wakeup_counter;
+static unsigned int control_cpu; /* The cpu assigned to collect stat and update
+				  * control parameters. default to BSP but BSP
+				  * can be offlined.
+				  */
+static bool clamping;
+
+
+static struct task_struct * __percpu *powerclamp_thread;
+static struct thermal_cooling_device *cooling_dev;
+static unsigned long *cpu_clamping_mask;  /* bit map for tracking per cpu
+					   * clamping thread
+					   */
+
+static unsigned int duration;
+static unsigned int pkg_cstate_ratio_cur;
+static unsigned int window_size;
+
+static int duration_set(const char *arg, const struct kernel_param *kp)
+{
+	int ret = 0;
+	unsigned long new_duration;
+
+	ret = kstrtoul(arg, 10, &new_duration);
+	if (ret)
+		goto exit;
+	if (new_duration > 25 || new_duration < 6) {
+		pr_err("Out of recommended range %lu, between 6-25ms\n",
+			new_duration);
+		ret = -EINVAL;
+	}
+
+	duration = clamp(new_duration, 6ul, 25ul);
+	smp_mb();
+
+exit:
+
+	return ret;
+}
+
+static struct kernel_param_ops duration_ops = {
+	.set = duration_set,
+	.get = param_get_int,
+};
+
+
+module_param_cb(duration, &duration_ops, &duration, 0644);
+MODULE_PARM_DESC(duration, "forced idle time for each attempt in msec.");
+
+struct powerclamp_calibration_data {
+	unsigned long confidence;  /* used for calibration, basically a counter
+				    * gets incremented each time a clamping
+				    * period is completed without extra wakeups
+				    * once that counter is reached given level,
+				    * compensation is deemed usable.
+				    */
+	unsigned long steady_comp; /* steady state compensation used when
+				    * no extra wakeups occurred.
+				    */
+	unsigned long dynamic_comp; /* compensate excessive wakeup from idle
+				     * mostly from external interrupts.
+				     */
+};
+
+static struct powerclamp_calibration_data cal_data[MAX_TARGET_RATIO];
+
+static int window_size_set(const char *arg, const struct kernel_param *kp)
+{
+	int ret = 0;
+	unsigned long new_window_size;
+
+	ret = kstrtoul(arg, 10, &new_window_size);
+	if (ret)
+		goto exit_win;
+	if (new_window_size > 10 || new_window_size < 2) {
+		pr_err("Out of recommended window size %lu, between 2-10\n",
+			new_window_size);
+		ret = -EINVAL;
+	}
+
+	window_size = clamp(new_window_size, 2ul, 10ul);
+	smp_mb();
+
+exit_win:
+
+	return ret;
+}
+
+static struct kernel_param_ops window_size_ops = {
+	.set = window_size_set,
+	.get = param_get_int,
+};
+
+module_param_cb(window_size, &window_size_ops, &window_size, 0644);
+MODULE_PARM_DESC(window_size, "sliding window in number of clamping cycles\n"
+	"\tpowerclamp controls idle ratio within this window. larger\n"
+	"\twindow size results in slower response time but more smooth\n"
+	"\tclamping results. default to 2.");
+
+static void find_target_mwait(void)
+{
+	unsigned int eax, ebx, ecx, edx;
+	unsigned int highest_cstate = 0;
+	unsigned int highest_subcstate = 0;
+	int i;
+
+	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
+		return;
+
+	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
+
+	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
+	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
+		return;
+
+	edx >>= MWAIT_SUBSTATE_SIZE;
+	for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
+		if (edx & MWAIT_SUBSTATE_MASK) {
+			highest_cstate = i;
+			highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
+		}
+	}
+	target_mwait = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
+		(highest_subcstate - 1);
+
+}
+
+struct pkg_cstate_info {
+	bool skip;
+	int msr_index;
+	int cstate_id;
+};
+
+#define PKG_CSTATE_INIT(id) {				\
+		.msr_index = MSR_PKG_C##id##_RESIDENCY, \
+		.cstate_id = id				\
+			}
+
+static struct pkg_cstate_info pkg_cstates[] = {
+	PKG_CSTATE_INIT(2),
+	PKG_CSTATE_INIT(3),
+	PKG_CSTATE_INIT(6),
+	PKG_CSTATE_INIT(7),
+	PKG_CSTATE_INIT(8),
+	PKG_CSTATE_INIT(9),
+	PKG_CSTATE_INIT(10),
+	{NULL},
+};
+
+static bool has_pkg_state_counter(void)
+{
+	u64 val;
+	struct pkg_cstate_info *info = pkg_cstates;
+
+	/* check if any one of the counter msrs exists */
+	while (info->msr_index) {
+		if (!rdmsrl_safe(info->msr_index, &val))
+			return true;
+		info++;
+	}
+
+	return false;
+}
+
+static u64 pkg_state_counter(void)
+{
+	u64 val;
+	u64 count = 0;
+	struct pkg_cstate_info *info = pkg_cstates;
+
+	while (info->msr_index) {
+		if (!info->skip) {
+			if (!rdmsrl_safe(info->msr_index, &val))
+				count += val;
+			else
+				info->skip = true;
+		}
+		info++;
+	}
+
+	return count;
+}
+
+static void noop_timer(unsigned long foo)
+{
+	/* empty... just the fact that we get the interrupt wakes us up */
+}
+
+static unsigned int get_compensation(int ratio)
+{
+	unsigned int comp = 0;
+
+	/* we only use compensation if all adjacent ones are good */
+	if (ratio == 1 &&
+		cal_data[ratio].confidence >= CONFIDENCE_OK &&
+		cal_data[ratio + 1].confidence >= CONFIDENCE_OK &&
+		cal_data[ratio + 2].confidence >= CONFIDENCE_OK) {
+		comp = (cal_data[ratio].steady_comp +
+			cal_data[ratio + 1].steady_comp +
+			cal_data[ratio + 2].steady_comp) / 3;
+	} else if (ratio == MAX_TARGET_RATIO - 1 &&
+		cal_data[ratio].confidence >= CONFIDENCE_OK &&
+		cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
+		cal_data[ratio - 2].confidence >= CONFIDENCE_OK) {
+		comp = (cal_data[ratio].steady_comp +
+			cal_data[ratio - 1].steady_comp +
+			cal_data[ratio - 2].steady_comp) / 3;
+	} else if (cal_data[ratio].confidence >= CONFIDENCE_OK &&
+		cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
+		cal_data[ratio + 1].confidence >= CONFIDENCE_OK) {
+		comp = (cal_data[ratio].steady_comp +
+			cal_data[ratio - 1].steady_comp +
+			cal_data[ratio + 1].steady_comp) / 3;
+	}
+
+	/* REVISIT: simple penalty of double idle injection */
+	if (reduce_irq)
+		comp = ratio;
+	/* do not exceed limit */
+	if (comp + ratio >= MAX_TARGET_RATIO)
+		comp = MAX_TARGET_RATIO - ratio - 1;
+
+	return comp;
+}
+
+static void adjust_compensation(int target_ratio, unsigned int win)
+{
+	int delta;
+	struct powerclamp_calibration_data *d = &cal_data[target_ratio];
+
+	/*
+	 * adjust compensations if confidence level has not been reached or
+	 * there are too many wakeups during the last idle injection period, we
+	 * cannot trust the data for compensation.
+	 */
+	if (d->confidence >= CONFIDENCE_OK ||
+		atomic_read(&idle_wakeup_counter) >
+		win * num_online_cpus())
+		return;
+
+	delta = set_target_ratio - current_ratio;
+	/* filter out bad data */
+	if (delta >= 0 && delta <= (1+target_ratio/10)) {
+		if (d->steady_comp)
+			d->steady_comp =
+				roundup(delta+d->steady_comp, 2)/2;
+		else
+			d->steady_comp = delta;
+		d->confidence++;
+	}
+}
+
+static bool powerclamp_adjust_controls(unsigned int target_ratio,
+				unsigned int guard, unsigned int win)
+{
+	static u64 msr_last, tsc_last;
+	u64 msr_now, tsc_now;
+	u64 val64;
+
+	/* check result for the last window */
+	msr_now = pkg_state_counter();
+	rdtscll(tsc_now);
+
+	/* calculate pkg cstate vs tsc ratio */
+	if (!msr_last || !tsc_last)
+		current_ratio = 1;
+	else if (tsc_now-tsc_last) {
+		val64 = 100*(msr_now-msr_last);
+		do_div(val64, (tsc_now-tsc_last));
+		current_ratio = val64;
+	}
+
+	/* update record */
+	msr_last = msr_now;
+	tsc_last = tsc_now;
+
+	adjust_compensation(target_ratio, win);
+	/*
+	 * too many external interrupts, set flag such
+	 * that we can take measure later.
+	 */
+	reduce_irq = atomic_read(&idle_wakeup_counter) >=
+		2 * win * num_online_cpus();
+
+	atomic_set(&idle_wakeup_counter, 0);
+	/* if we are above target+guard, skip */
+	return set_target_ratio + guard <= current_ratio;
+}
+
+static int clamp_thread(void *arg)
+{
+	int cpunr = (unsigned long)arg;
+	DEFINE_TIMER(wakeup_timer, noop_timer, 0, 0);
+	static const struct sched_param param = {
+		.sched_priority = MAX_USER_RT_PRIO/2,
+	};
+	unsigned int count = 0;
+	unsigned int target_ratio;
+
+	set_bit(cpunr, cpu_clamping_mask);
+	set_freezable();
+	init_timer_on_stack(&wakeup_timer);
+	sched_setscheduler(current, SCHED_FIFO, &param);
+
+	while (true == clamping && !kthread_should_stop() &&
+		cpu_online(cpunr)) {
+		int sleeptime;
+		unsigned long target_jiffies;
+		unsigned int guard;
+		unsigned int compensation = 0;
+		int interval; /* jiffies to sleep for each attempt */
+		unsigned int duration_jiffies = msecs_to_jiffies(duration);
+		unsigned int window_size_now;
+
+		try_to_freeze();
+		/*
+		 * make sure user selected ratio does not take effect until
+		 * the next round. adjust target_ratio if user has changed
+		 * target such that we can converge quickly.
+		 */
+		target_ratio = set_target_ratio;
+		guard = 1 + target_ratio/20;
+		window_size_now = window_size;
+		count++;
+
+		/*
+		 * systems may have different ability to enter package level
+		 * c-states, thus we need to compensate the injected idle ratio
+		 * to achieve the actual target reported by the HW.
+		 */
+		compensation = get_compensation(target_ratio);
+		interval = duration_jiffies*100/(target_ratio+compensation);
+
+		/* align idle time */
+		target_jiffies = roundup(jiffies, interval);
+		sleeptime = target_jiffies - jiffies;
+		if (sleeptime <= 0)
+			sleeptime = 1;
+		schedule_timeout_interruptible(sleeptime);
+		/*
+		 * only elected controlling cpu can collect stats and update
+		 * control parameters.
+		 */
+		if (cpunr == control_cpu && !(count%window_size_now)) {
+			should_skip =
+				powerclamp_adjust_controls(target_ratio,
+							guard, window_size_now);
+			smp_mb();
+		}
+
+		if (should_skip)
+			continue;
+
+		target_jiffies = jiffies + duration_jiffies;
+		mod_timer(&wakeup_timer, target_jiffies);
+		if (unlikely(local_softirq_pending()))
+			continue;
+		/*
+		 * stop tick sched during idle time, interrupts are still
+		 * allowed. thus jiffies are updated properly.
+		 */
+		preempt_disable();
+		/* mwait until target jiffies is reached */
+		while (time_before(jiffies, target_jiffies)) {
+			unsigned long ecx = 1;
+			unsigned long eax = target_mwait;
+
+			/*
+			 * REVISIT: may call enter_idle() to notify drivers who
+			 * can save power during cpu idle. same for exit_idle()
+			 */
+			local_touch_nmi();
+			stop_critical_timings();
+			mwait_idle_with_hints(eax, ecx);
+			start_critical_timings();
+			atomic_inc(&idle_wakeup_counter);
+		}
+		preempt_enable();
+	}
+	del_timer_sync(&wakeup_timer);
+	clear_bit(cpunr, cpu_clamping_mask);
+
+	return 0;
+}
+
+/*
+ * 1 HZ polling while clamping is active, useful for userspace
+ * to monitor actual idle ratio.
+ */
+static void poll_pkg_cstate(struct work_struct *dummy);
+static DECLARE_DELAYED_WORK(poll_pkg_cstate_work, poll_pkg_cstate);
+static void poll_pkg_cstate(struct work_struct *dummy)
+{
+	static u64 msr_last;
+	static u64 tsc_last;
+	static unsigned long jiffies_last;
+
+	u64 msr_now;
+	unsigned long jiffies_now;
+	u64 tsc_now;
+	u64 val64;
+
+	msr_now = pkg_state_counter();
+	rdtscll(tsc_now);
+	jiffies_now = jiffies;
+
+	/* calculate pkg cstate vs tsc ratio */
+	if (!msr_last || !tsc_last)
+		pkg_cstate_ratio_cur = 1;
+	else {
+		if (tsc_now - tsc_last) {
+			val64 = 100 * (msr_now - msr_last);
+			do_div(val64, (tsc_now - tsc_last));
+			pkg_cstate_ratio_cur = val64;
+		}
+	}
+
+	/* update record */
+	msr_last = msr_now;
+	jiffies_last = jiffies_now;
+	tsc_last = tsc_now;
+
+	if (true == clamping)
+		schedule_delayed_work(&poll_pkg_cstate_work, HZ);
+}
+
+static int start_power_clamp(void)
+{
+	unsigned long cpu;
+	struct task_struct *thread;
+
+	/* check if pkg cstate counter is completely 0, abort in this case */
+	if (!has_pkg_state_counter()) {
+		pr_err("pkg cstate counter not functional, abort\n");
+		return -EINVAL;
+	}
+
+	set_target_ratio = clamp(set_target_ratio, 0U, MAX_TARGET_RATIO - 1);
+	/* prevent cpu hotplug */
+	get_online_cpus();
+
+	/* prefer BSP */
+	control_cpu = 0;
+	if (!cpu_online(control_cpu))
+		control_cpu = smp_processor_id();
+
+	clamping = true;
+	schedule_delayed_work(&poll_pkg_cstate_work, 0);
+
+	/* start one thread per online cpu */
+	for_each_online_cpu(cpu) {
+		struct task_struct **p =
+			per_cpu_ptr(powerclamp_thread, cpu);
+
+		thread = kthread_create_on_node(clamp_thread,
+						(void *) cpu,
+						cpu_to_node(cpu),
+						"kidle_inject/%ld", cpu);
+		/* bind to cpu here */
+		if (likely(!IS_ERR(thread))) {
+			kthread_bind(thread, cpu);
+			wake_up_process(thread);
+			*p = thread;
+		}
+
+	}
+	put_online_cpus();
+
+	return 0;
+}
+
+static void end_power_clamp(void)
+{
+	int i;
+	struct task_struct *thread;
+
+	clamping = false;
+	/*
+	 * make clamping visible to other cpus and give per cpu clamping threads
+	 * sometime to exit, or gets killed later.
+	 */
+	smp_mb();
+	msleep(20);
+	if (bitmap_weight(cpu_clamping_mask, num_possible_cpus())) {
+		for_each_set_bit(i, cpu_clamping_mask, num_possible_cpus()) {
+			pr_debug("clamping thread for cpu %d alive, kill\n", i);
+			thread = *per_cpu_ptr(powerclamp_thread, i);
+			kthread_stop(thread);
+		}
+	}
+}
+
+static int powerclamp_cpu_callback(struct notifier_block *nfb,
+				unsigned long action, void *hcpu)
+{
+	unsigned long cpu = (unsigned long)hcpu;
+	struct task_struct *thread;
+	struct task_struct **percpu_thread =
+		per_cpu_ptr(powerclamp_thread, cpu);
+
+	if (false == clamping)
+		goto exit_ok;
+
+	switch (action) {
+	case CPU_ONLINE:
+		thread = kthread_create_on_node(clamp_thread,
+						(void *) cpu,
+						cpu_to_node(cpu),
+						"kidle_inject/%lu", cpu);
+		if (likely(!IS_ERR(thread))) {
+			kthread_bind(thread, cpu);
+			wake_up_process(thread);
+			*percpu_thread = thread;
+		}
+		/* prefer BSP as controlling CPU */
+		if (cpu == 0) {
+			control_cpu = 0;
+			smp_mb();
+		}
+		break;
+	case CPU_DEAD:
+		if (test_bit(cpu, cpu_clamping_mask)) {
+			pr_err("cpu %lu dead but powerclamping thread is not\n",
+				cpu);
+			kthread_stop(*percpu_thread);
+		}
+		if (cpu == control_cpu) {
+			control_cpu = smp_processor_id();
+			smp_mb();
+		}
+	}
+
+exit_ok:
+	return NOTIFY_OK;
+}
+
+static struct notifier_block powerclamp_cpu_notifier = {
+	.notifier_call = powerclamp_cpu_callback,
+};
+
+static int powerclamp_get_max_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	*state = MAX_TARGET_RATIO;
+
+	return 0;
+}
+
+static int powerclamp_get_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long *state)
+{
+	if (true == clamping)
+		*state = pkg_cstate_ratio_cur;
+	else
+		/* to save power, do not poll idle ratio while not clamping */
+		*state = -1; /* indicates invalid state */
+
+	return 0;
+}
+
+static int powerclamp_set_cur_state(struct thermal_cooling_device *cdev,
+				 unsigned long new_target_ratio)
+{
+	int ret = 0;
+
+	new_target_ratio = clamp(new_target_ratio, 0UL,
+				(unsigned long) (MAX_TARGET_RATIO-1));
+	if (set_target_ratio == 0 && new_target_ratio > 0) {
+		pr_info("Start idle injection to reduce power\n");
+		set_target_ratio = new_target_ratio;
+		ret = start_power_clamp();
+		goto exit_set;
+	} else	if (set_target_ratio > 0 && new_target_ratio == 0) {
+		pr_info("Stop forced idle injection\n");
+		set_target_ratio = 0;
+		end_power_clamp();
+	} else	/* adjust currently running */ {
+		set_target_ratio = new_target_ratio;
+		/* make new set_target_ratio visible to other cpus */
+		smp_mb();
+	}
+
+exit_set:
+	return ret;
+}
+
+/* bind to generic thermal layer as cooling device*/
+static struct thermal_cooling_device_ops powerclamp_cooling_ops = {
+	.get_max_state = powerclamp_get_max_state,
+	.get_cur_state = powerclamp_get_cur_state,
+	.set_cur_state = powerclamp_set_cur_state,
+};
+
+/* runs on Nehalem and later */
+static const struct x86_cpu_id intel_powerclamp_ids[] __initconst = {
+	{ X86_VENDOR_INTEL, 6, 0x1a},
+	{ X86_VENDOR_INTEL, 6, 0x1c},
+	{ X86_VENDOR_INTEL, 6, 0x1e},
+	{ X86_VENDOR_INTEL, 6, 0x1f},
+	{ X86_VENDOR_INTEL, 6, 0x25},
+	{ X86_VENDOR_INTEL, 6, 0x26},
+	{ X86_VENDOR_INTEL, 6, 0x2a},
+	{ X86_VENDOR_INTEL, 6, 0x2c},
+	{ X86_VENDOR_INTEL, 6, 0x2d},
+	{ X86_VENDOR_INTEL, 6, 0x2e},
+	{ X86_VENDOR_INTEL, 6, 0x2f},
+	{ X86_VENDOR_INTEL, 6, 0x37},
+	{ X86_VENDOR_INTEL, 6, 0x3a},
+	{ X86_VENDOR_INTEL, 6, 0x3c},
+	{ X86_VENDOR_INTEL, 6, 0x3d},
+	{ X86_VENDOR_INTEL, 6, 0x3e},
+	{ X86_VENDOR_INTEL, 6, 0x3f},
+	{ X86_VENDOR_INTEL, 6, 0x45},
+	{ X86_VENDOR_INTEL, 6, 0x46},
+	{ X86_VENDOR_INTEL, 6, 0x4c},
+	{ X86_VENDOR_INTEL, 6, 0x4d},
+	{ X86_VENDOR_INTEL, 6, 0x4f},
+	{ X86_VENDOR_INTEL, 6, 0x56},
+	{}
+};
+MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids);
+
+static int __init powerclamp_probe(void)
+{
+	if (!x86_match_cpu(intel_powerclamp_ids)) {
+		pr_err("Intel powerclamp does not run on family %d model %d\n",
+				boot_cpu_data.x86, boot_cpu_data.x86_model);
+		return -ENODEV;
+	}
+	if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC) ||
+		!boot_cpu_has(X86_FEATURE_CONSTANT_TSC) ||
+		!boot_cpu_has(X86_FEATURE_MWAIT) ||
+		!boot_cpu_has(X86_FEATURE_ARAT))
+		return -ENODEV;
+
+	/* find the deepest mwait value */
+	find_target_mwait();
+
+	return 0;
+}
+
+static int powerclamp_debug_show(struct seq_file *m, void *unused)
+{
+	int i = 0;
+
+	seq_printf(m, "controlling cpu: %d\n", control_cpu);
+	seq_printf(m, "pct confidence steady dynamic (compensation)\n");
+	for (i = 0; i < MAX_TARGET_RATIO; i++) {
+		seq_printf(m, "%d\t%lu\t%lu\t%lu\n",
+			i,
+			cal_data[i].confidence,
+			cal_data[i].steady_comp,
+			cal_data[i].dynamic_comp);
+	}
+
+	return 0;
+}
+
+static int powerclamp_debug_open(struct inode *inode,
+			struct file *file)
+{
+	return single_open(file, powerclamp_debug_show, inode->i_private);
+}
+
+static const struct file_operations powerclamp_debug_fops = {
+	.open		= powerclamp_debug_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.owner		= THIS_MODULE,
+};
+
+static inline void powerclamp_create_debug_files(void)
+{
+	debug_dir = debugfs_create_dir("intel_powerclamp", NULL);
+	if (!debug_dir)
+		return;
+
+	if (!debugfs_create_file("powerclamp_calib", S_IRUGO, debug_dir,
+					cal_data, &powerclamp_debug_fops))
+		goto file_error;
+
+	return;
+
+file_error:
+	debugfs_remove_recursive(debug_dir);
+}
+
+static int __init powerclamp_init(void)
+{
+	int retval;
+	int bitmap_size;
+
+	bitmap_size = BITS_TO_LONGS(num_possible_cpus()) * sizeof(long);
+	cpu_clamping_mask = kzalloc(bitmap_size, GFP_KERNEL);
+	if (!cpu_clamping_mask)
+		return -ENOMEM;
+
+	/* probe cpu features and ids here */
+	retval = powerclamp_probe();
+	if (retval)
+		goto exit_free;
+
+	/* set default limit, maybe adjusted during runtime based on feedback */
+	window_size = 2;
+	register_hotcpu_notifier(&powerclamp_cpu_notifier);
+
+	powerclamp_thread = alloc_percpu(struct task_struct *);
+	if (!powerclamp_thread) {
+		retval = -ENOMEM;
+		goto exit_unregister;
+	}
+
+	cooling_dev = thermal_cooling_device_register("intel_powerclamp", NULL,
+						&powerclamp_cooling_ops);
+	if (IS_ERR(cooling_dev)) {
+		retval = -ENODEV;
+		goto exit_free_thread;
+	}
+
+	if (!duration)
+		duration = jiffies_to_msecs(DEFAULT_DURATION_JIFFIES);
+
+	powerclamp_create_debug_files();
+
+	return 0;
+
+exit_free_thread:
+	free_percpu(powerclamp_thread);
+exit_unregister:
+	unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
+exit_free:
+	kfree(cpu_clamping_mask);
+	return retval;
+}
+module_init(powerclamp_init);
+
+static void __exit powerclamp_exit(void)
+{
+	unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
+	end_power_clamp();
+	free_percpu(powerclamp_thread);
+	thermal_cooling_device_unregister(cooling_dev);
+	kfree(cpu_clamping_mask);
+
+	cancel_delayed_work_sync(&poll_pkg_cstate_work);
+	debugfs_remove_recursive(debug_dir);
+}
+module_exit(powerclamp_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
+MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
+MODULE_DESCRIPTION("Package Level C-state Idle Injection for Intel CPUs");