Merge tag 'pci-v5.5-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
[linux-2.6-microblaze.git] / drivers / devfreq / tegra30-devfreq.c
index a6ba75f..0b65f89 100644 (file)
 #include <linux/devfreq.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/irq.h>
 #include <linux/module.h>
-#include <linux/mod_devicetable.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_opp.h>
 #include <linux/reset.h>
+#include <linux/workqueue.h>
 
 #include "governor.h"
 
@@ -33,6 +35,8 @@
 #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
@@ -68,6 +72,8 @@
 
 #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
 
@@ -90,9 +96,10 @@ struct tegra_devfreq_device_config {
        unsigned int    boost_down_threshold;
 
        /*
-        * Threshold of activity (cycles) 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.
+        * 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;
 };
@@ -102,7 +109,7 @@ enum tegra_actmon_device {
        MCCPU,
 };
 
-static struct tegra_devfreq_device_config actmon_device_configs[] = {
+static const struct tegra_devfreq_device_config actmon_device_configs[] = {
        {
                /* MCALL: All memory accesses (including from the CPUs) */
                .offset = 0x1c0,
@@ -117,10 +124,10 @@ static struct tegra_devfreq_device_config actmon_device_configs[] = {
                .offset = 0x200,
                .irq_mask = 1 << 25,
                .boost_up_coeff = 800,
-               .boost_down_coeff = 90,
+               .boost_down_coeff = 40,
                .boost_up_threshold = 27,
                .boost_down_threshold = 10,
-               .avg_dependency_threshold = 50000,
+               .avg_dependency_threshold = 16000, /* 16MHz in kHz units */
        },
 };
 
@@ -156,11 +163,16 @@ struct tegra_devfreq {
        struct clk              *emc_clock;
        unsigned long           max_freq;
        unsigned long           cur_freq;
-       struct notifier_block   rate_change_nb;
+       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[ARRAY_SIZE(actmon_device_configs)];
 
-       int irq;
+       unsigned int            irq;
+
+       bool                    started;
 };
 
 struct tegra_actmon_emc_ratio {
@@ -168,8 +180,8 @@ struct tegra_actmon_emc_ratio {
        unsigned long emc_freq;
 };
 
-static struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
-       { 1400000, ULONG_MAX },
+static const struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
+       { 1400000,    KHZ_MAX },
        { 1200000,    750000 },
        { 1100000,    600000 },
        { 1000000,    500000 },
@@ -199,18 +211,26 @@ static void device_writel(struct tegra_devfreq_device *dev, u32 val,
        writel_relaxed(val, dev->regs + offset);
 }
 
-static unsigned long do_percent(unsigned long val, unsigned int pct)
+static unsigned long do_percent(unsigned long long val, unsigned int pct)
 {
-       return val * pct / 100;
+       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 = dev->avg_count;
        u32 avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
-       u32 band = avg_band_freq * ACTMON_SAMPLING_PERIOD;
+       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);
@@ -220,7 +240,7 @@ static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
 static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
                                       struct tegra_devfreq_device *dev)
 {
-       u32 val = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
+       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);
@@ -229,12 +249,6 @@ static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
                      ACTMON_DEV_LOWER_WMARK);
 }
 
-static void actmon_write_barrier(struct tegra_devfreq *tegra)
-{
-       /* ensure the update has reached the ACTMON */
-       readl(tegra->regs + ACTMON_GLB_STATUS);
-}
-
 static void actmon_isr_device(struct tegra_devfreq *tegra,
                              struct tegra_devfreq_device *dev)
 {
@@ -256,10 +270,10 @@ static void actmon_isr_device(struct tegra_devfreq *tegra,
 
                dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 
-               if (dev->boost_freq >= tegra->max_freq)
+               if (dev->boost_freq >= tegra->max_freq) {
+                       dev_ctrl &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
                        dev->boost_freq = tegra->max_freq;
-               else
-                       dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
+               }
        } else if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) {
                /*
                 * new_boost = old_boost * down_coef
@@ -270,31 +284,22 @@ static void actmon_isr_device(struct tegra_devfreq *tegra,
 
                dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
 
-               if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> 1))
-                       dev->boost_freq = 0;
-               else
-                       dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
-       }
-
-       if (dev->config->avg_dependency_threshold) {
-               if (dev->avg_count >= dev->config->avg_dependency_threshold)
-                       dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
-               else if (dev->boost_freq == 0)
+               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);
-
-       actmon_write_barrier(tegra);
 }
 
 static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
                                            unsigned long cpu_freq)
 {
        unsigned int i;
-       struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios;
+       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) {
@@ -308,25 +313,37 @@ static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
        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;
-       unsigned int avg_sustain_coef;
 
-       if (dev->config->avg_dependency_threshold) {
-               cpu_freq = cpufreq_get(0);
-               static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
-       }
+       dev->target_freq = actmon_device_target_freq(tegra, dev);
 
-       dev->target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD;
-       avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
-       dev->target_freq = do_percent(dev->target_freq, avg_sustain_coef);
-       dev->target_freq += dev->boost_freq;
+       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);
 
-       if (dev->avg_count >= dev->config->avg_dependency_threshold)
+               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)
@@ -354,8 +371,8 @@ static irqreturn_t actmon_thread_isr(int irq, void *data)
        return handled ? IRQ_HANDLED : IRQ_NONE;
 }
 
-static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
-                                      unsigned long action, void *ptr)
+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;
@@ -365,7 +382,7 @@ static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
        if (action != POST_RATE_CHANGE)
                return NOTIFY_OK;
 
-       tegra = container_of(nb, struct tegra_devfreq, rate_change_nb);
+       tegra = container_of(nb, struct tegra_devfreq, clk_rate_change_nb);
 
        tegra->cur_freq = data->new_rate / KHZ;
 
@@ -375,7 +392,79 @@ static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
                tegra_devfreq_update_wmark(tegra, dev);
        }
 
-       actmon_write_barrier(tegra);
+       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 >= 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;
 }
@@ -385,9 +474,12 @@ static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
 {
        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 * ACTMON_SAMPLING_PERIOD;
+       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);
@@ -405,45 +497,116 @@ static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
                << 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_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_start(struct tegra_devfreq *tegra)
+static void tegra_actmon_stop_devices(struct tegra_devfreq *tegra)
 {
+       struct tegra_devfreq_device *dev = tegra->devices;
        unsigned int i;
 
-       disable_irq(tegra->irq);
+       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);
+       }
+}
 
-       actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1,
+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]);
 
-       actmon_write_barrier(tegra);
+       /*
+        * 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 void tegra_actmon_stop(struct tegra_devfreq *tegra)
+static int tegra_actmon_start(struct tegra_devfreq *tegra)
 {
-       unsigned int i;
+       int ret = 0;
 
-       disable_irq(tegra->irq);
+       if (!tegra->started) {
+               tegra->started = true;
 
-       for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
-               device_writel(&tegra->devices[i], 0x00000000, ACTMON_DEV_CTRL);
-               device_writel(&tegra->devices[i], ACTMON_INTR_STATUS_CLEAR,
-                             ACTMON_DEV_INTR_STATUS);
+               ret = tegra_actmon_resume(tegra);
+               if (ret)
+                       tegra->started = false;
        }
 
-       actmon_write_barrier(tegra);
+       return ret;
+}
 
-       enable_irq(tegra->irq);
+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,
@@ -463,7 +626,7 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
        rate = dev_pm_opp_get_freq(opp);
        dev_pm_opp_put(opp);
 
-       err = clk_set_min_rate(tegra->emc_clock, rate);
+       err = clk_set_min_rate(tegra->emc_clock, rate * KHZ);
        if (err)
                return err;
 
@@ -492,7 +655,7 @@ static int tegra_devfreq_get_dev_status(struct device *dev,
        stat->private_data = tegra;
 
        /* The below are to be used by the other governors */
-       stat->current_frequency = cur_freq * KHZ;
+       stat->current_frequency = cur_freq;
 
        actmon_dev = &tegra->devices[MCALL];
 
@@ -503,7 +666,7 @@ static int tegra_devfreq_get_dev_status(struct device *dev,
        stat->busy_time *= 100 / BUS_SATURATION_RATIO;
 
        /* Number of cycles in a sampling period */
-       stat->total_time = ACTMON_SAMPLING_PERIOD * cur_freq;
+       stat->total_time = tegra->devfreq->profile->polling_ms * cur_freq;
 
        stat->busy_time = min(stat->busy_time, stat->total_time);
 
@@ -511,7 +674,7 @@ static int tegra_devfreq_get_dev_status(struct device *dev,
 }
 
 static struct devfreq_dev_profile tegra_devfreq_profile = {
-       .polling_ms     = 0,
+       .polling_ms     = ACTMON_SAMPLING_PERIOD,
        .target         = tegra_devfreq_target,
        .get_dev_status = tegra_devfreq_get_dev_status,
 };
@@ -542,7 +705,7 @@ static int tegra_governor_get_target(struct devfreq *devfreq,
                target_freq = max(target_freq, dev->target_freq);
        }
 
-       *freq = target_freq * KHZ;
+       *freq = target_freq;
 
        return 0;
 }
@@ -551,11 +714,19 @@ 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);
-               tegra_actmon_start(tegra);
+               ret = tegra_actmon_start(tegra);
                break;
 
        case DEVFREQ_GOV_STOP:
@@ -563,6 +734,21 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
                devfreq_monitor_stop(devfreq);
                break;
 
+       case DEVFREQ_GOV_INTERVAL:
+               /*
+                * ACTMON hardware supports up to 256 milliseconds for the
+                * sampling period.
+                */
+               if (*new_delay > 256) {
+                       ret = -EINVAL;
+                       break;
+               }
+
+               tegra_actmon_pause(tegra);
+               devfreq_interval_update(devfreq, new_delay);
+               ret = tegra_actmon_resume(tegra);
+               break;
+
        case DEVFREQ_GOV_SUSPEND:
                tegra_actmon_stop(tegra);
                devfreq_monitor_suspend(devfreq);
@@ -570,11 +756,11 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
 
        case DEVFREQ_GOV_RESUME:
                devfreq_monitor_resume(devfreq);
-               tegra_actmon_start(tegra);
+               ret = tegra_actmon_start(tegra);
                break;
        }
 
-       return 0;
+       return ret;
 }
 
 static struct devfreq_governor tegra_devfreq_governor = {
@@ -582,14 +768,16 @@ static struct devfreq_governor tegra_devfreq_governor = {
        .get_target_freq = tegra_governor_get_target,
        .event_handler = tegra_governor_event_handler,
        .immutable = true,
+       .interrupt_driven = true,
 };
 
 static int tegra_devfreq_probe(struct platform_device *pdev)
 {
-       struct tegra_devfreq *tegra;
        struct tegra_devfreq_device *dev;
+       struct tegra_devfreq *tegra;
+       struct devfreq *devfreq;
        unsigned int i;
-       unsigned long rate;
+       long rate;
        int err;
 
        tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
@@ -618,12 +806,22 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
                return PTR_ERR(tegra->emc_clock);
        }
 
-       tegra->irq = platform_get_irq(pdev, 0);
-       if (tegra->irq < 0) {
-               err = tegra->irq;
+       err = platform_get_irq(pdev, 0);
+       if (err < 0) {
                dev_err(&pdev->dev, "Failed to get IRQ: %d\n", err);
                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;
+       }
 
        reset_control_assert(tegra->reset);
 
@@ -636,8 +834,13 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
 
        reset_control_deassert(tegra->reset);
 
-       tegra->max_freq = clk_round_rate(tegra->emc_clock, ULONG_MAX) / KHZ;
-       tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ;
+       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;
+       }
+
+       tegra->max_freq = rate / KHZ;
 
        for (i = 0; i < ARRAY_SIZE(actmon_device_configs); i++) {
                dev = tegra->devices + i;
@@ -648,7 +851,14 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
        for (rate = 0; rate <= tegra->max_freq * KHZ; rate++) {
                rate = clk_round_rate(tegra->emc_clock, rate);
 
-               err = dev_pm_opp_add(&pdev->dev, rate, 0);
+               if (rate < 0) {
+                       dev_err(&pdev->dev,
+                               "Failed to round clock rate: %ld\n", rate);
+                       err = rate;
+                       goto remove_opps;
+               }
+
+               err = dev_pm_opp_add(&pdev->dev, rate / KHZ, 0);
                if (err) {
                        dev_err(&pdev->dev, "Failed to add OPP: %d\n", err);
                        goto remove_opps;
@@ -657,49 +867,33 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
 
        platform_set_drvdata(pdev, tegra);
 
-       tegra->rate_change_nb.notifier_call = tegra_actmon_rate_notify_cb;
-       err = clk_notifier_register(tegra->emc_clock, &tegra->rate_change_nb);
-       if (err) {
-               dev_err(&pdev->dev,
-                       "Failed to register rate change notifier\n");
-               goto remove_opps;
-       }
+       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 = devfreq_add_governor(&tegra_devfreq_governor);
        if (err) {
                dev_err(&pdev->dev, "Failed to add governor: %d\n", err);
-               goto unreg_notifier;
+               goto remove_opps;
        }
 
        tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
-       tegra->devfreq = devfreq_add_device(&pdev->dev,
-                                           &tegra_devfreq_profile,
-                                           "tegra_actmon",
-                                           NULL);
-       if (IS_ERR(tegra->devfreq)) {
-               err = PTR_ERR(tegra->devfreq);
-               goto remove_governor;
-       }
+       tegra_devfreq_profile.initial_freq /= KHZ;
 
-       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);
-               goto remove_devfreq;
+       devfreq = devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
+                                    "tegra_actmon", NULL);
+       if (IS_ERR(devfreq)) {
+               err = PTR_ERR(devfreq);
+               goto remove_governor;
        }
 
        return 0;
 
-remove_devfreq:
-       devfreq_remove_device(tegra->devfreq);
-
 remove_governor:
        devfreq_remove_governor(&tegra_devfreq_governor);
 
-unreg_notifier:
-       clk_notifier_unregister(tegra->emc_clock, &tegra->rate_change_nb);
-
 remove_opps:
        dev_pm_opp_remove_all_dynamic(&pdev->dev);
 
@@ -716,7 +910,6 @@ static int tegra_devfreq_remove(struct platform_device *pdev)
        devfreq_remove_device(tegra->devfreq);
        devfreq_remove_governor(&tegra_devfreq_governor);
 
-       clk_notifier_unregister(tegra->emc_clock, &tegra->rate_change_nb);
        dev_pm_opp_remove_all_dynamic(&pdev->dev);
 
        reset_control_reset(tegra->reset);