linux/drivers/devfreq/tegra-devfreq.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * A devfreq driver for NVIDIA Tegra SoCs
   4 *
   5 * Copyright (c) 2014 NVIDIA CORPORATION. All rights reserved.
   6 * Copyright (C) 2014 Google, Inc
   7 */
   8
   9#include <linux/clk.h>
  10#include <linux/cpufreq.h>
  11#include <linux/devfreq.h>
  12#include <linux/interrupt.h>
  13#include <linux/io.h>
  14#include <linux/module.h>
  15#include <linux/mod_devicetable.h>
  16#include <linux/platform_device.h>
  17#include <linux/pm_opp.h>
  18#include <linux/reset.h>
  19
  20#include "governor.h"
  21
  22#define ACTMON_GLB_STATUS                                       0x0
  23#define ACTMON_GLB_PERIOD_CTRL                                  0x4
  24
  25#define ACTMON_DEV_CTRL                                         0x0
  26#define ACTMON_DEV_CTRL_K_VAL_SHIFT                             10
  27#define ACTMON_DEV_CTRL_ENB_PERIODIC                            BIT(18)
  28#define ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN                      BIT(20)
  29#define ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN                      BIT(21)
  30#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT       23
  31#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT       26
  32#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN              BIT(29)
  33#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN              BIT(30)
  34#define ACTMON_DEV_CTRL_ENB                                     BIT(31)
  35
  36#define ACTMON_DEV_UPPER_WMARK                                  0x4
  37#define ACTMON_DEV_LOWER_WMARK                                  0x8
  38#define ACTMON_DEV_INIT_AVG                                     0xc
  39#define ACTMON_DEV_AVG_UPPER_WMARK                              0x10
  40#define ACTMON_DEV_AVG_LOWER_WMARK                              0x14
  41#define ACTMON_DEV_COUNT_WEIGHT                                 0x18
  42#define ACTMON_DEV_AVG_COUNT                                    0x20
  43#define ACTMON_DEV_INTR_STATUS                                  0x24
  44
  45#define ACTMON_INTR_STATUS_CLEAR                                0xffffffff
  46
  47#define ACTMON_DEV_INTR_CONSECUTIVE_UPPER                       BIT(31)
  48#define ACTMON_DEV_INTR_CONSECUTIVE_LOWER                       BIT(30)
  49
  50#define ACTMON_ABOVE_WMARK_WINDOW                               1
  51#define ACTMON_BELOW_WMARK_WINDOW                               3
  52#define ACTMON_BOOST_FREQ_STEP                                  16000
  53
  54/*
  55 * Activity counter is incremented every 256 memory transactions, and each
  56 * transaction takes 4 EMC clocks for Tegra124; So the COUNT_WEIGHT is
  57 * 4 * 256 = 1024.
  58 */
  59#define ACTMON_COUNT_WEIGHT                                     0x400
  60
  61/*
  62 * ACTMON_AVERAGE_WINDOW_LOG2: default value for @DEV_CTRL_K_VAL, which
  63 * translates to 2 ^ (K_VAL + 1). ex: 2 ^ (6 + 1) = 128
  64 */
  65#define ACTMON_AVERAGE_WINDOW_LOG2                      6
  66#define ACTMON_SAMPLING_PERIOD                          12 /* ms */
  67#define ACTMON_DEFAULT_AVG_BAND                         6  /* 1/10 of % */
  68
  69#define KHZ                                                     1000
  70
  71/* Assume that the bus is saturated if the utilization is 25% */
  72#define BUS_SATURATION_RATIO                                    25
  73
  74/**
  75 * struct tegra_devfreq_device_config - configuration specific to an ACTMON
  76 * device
  77 *
  78 * Coefficients and thresholds are percentages unless otherwise noted
  79 */
  80struct tegra_devfreq_device_config {
  81        u32             offset;
  82        u32             irq_mask;
  83
  84        /* Factors applied to boost_freq every consecutive watermark breach */
  85        unsigned int    boost_up_coeff;
  86        unsigned int    boost_down_coeff;
  87
  88        /* Define the watermark bounds when applied to the current avg */
  89        unsigned int    boost_up_threshold;
  90        unsigned int    boost_down_threshold;
  91
  92        /*
  93         * Threshold of activity (cycles) below which the CPU frequency isn't
  94         * to be taken into account. This is to avoid increasing the EMC
  95         * frequency when the CPU is very busy but not accessing the bus often.
  96         */
  97        u32             avg_dependency_threshold;
  98};
  99
 100enum tegra_actmon_device {
 101        MCALL = 0,
 102        MCCPU,
 103};
 104
 105static struct tegra_devfreq_device_config actmon_device_configs[] = {
 106        {
 107                /* MCALL: All memory accesses (including from the CPUs) */
 108                .offset = 0x1c0,
 109                .irq_mask = 1 << 26,
 110                .boost_up_coeff = 200,
 111                .boost_down_coeff = 50,
 112                .boost_up_threshold = 60,
 113                .boost_down_threshold = 40,
 114        },
 115        {
 116                /* MCCPU: memory accesses from the CPUs */
 117                .offset = 0x200,
 118                .irq_mask = 1 << 25,
 119                .boost_up_coeff = 800,
 120                .boost_down_coeff = 90,
 121                .boost_up_threshold = 27,
 122                .boost_down_threshold = 10,
 123                .avg_dependency_threshold = 50000,
 124        },
 125};
 126
 127/**
 128 * struct tegra_devfreq_device - state specific to an ACTMON device
 129 *
 130 * Frequencies are in kHz.
 131 */
 132struct tegra_devfreq_device {
 133        const struct tegra_devfreq_device_config *config;
 134        void __iomem *regs;
 135        spinlock_t lock;
 136
 137        /* Average event count sampled in the last interrupt */
 138        u32 avg_count;
 139
 140        /*
 141         * Extra frequency to increase the target by due to consecutive
 142         * watermark breaches.
 143         */
 144        unsigned long boost_freq;
 145
 146        /* Optimal frequency calculated from the stats for this device */
 147        unsigned long target_freq;
 148};
 149
 150struct tegra_devfreq {
 151        struct devfreq          *devfreq;
 152
 153        struct reset_control    *reset;
 154        struct clk              *clock;
 155        void __iomem            *regs;
 156
 157        struct clk              *emc_clock;
 158        unsigned long           max_freq;
 159        unsigned long           cur_freq;
 160        struct notifier_block   rate_change_nb;
 161
 162        struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
 163};
 164
 165struct tegra_actmon_emc_ratio {
 166        unsigned long cpu_freq;
 167        unsigned long emc_freq;
 168};
 169
 170static struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
 171        { 1400000, ULONG_MAX },
 172        { 1200000,    750000 },
 173        { 1100000,    600000 },
 174        { 1000000,    500000 },
 175        {  800000,    375000 },
 176        {  500000,    200000 },
 177        {  250000,    100000 },
 178};
 179
 180static u32 actmon_readl(struct tegra_devfreq *tegra, u32 offset)
 181{
 182        return readl(tegra->regs + offset);
 183}
 184
 185static void actmon_writel(struct tegra_devfreq *tegra, u32 val, u32 offset)
 186{
 187        writel(val, tegra->regs + offset);
 188}
 189
 190static u32 device_readl(struct tegra_devfreq_device *dev, u32 offset)
 191{
 192        return readl(dev->regs + offset);
 193}
 194
 195static void device_writel(struct tegra_devfreq_device *dev, u32 val,
 196                          u32 offset)
 197{
 198        writel(val, dev->regs + offset);
 199}
 200
 201static unsigned long do_percent(unsigned long val, unsigned int pct)
 202{
 203        return val * pct / 100;
 204}
 205
 206static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
 207                                           struct tegra_devfreq_device *dev)
 208{
 209        u32 avg = dev->avg_count;
 210        u32 avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
 211        u32 band = avg_band_freq * ACTMON_SAMPLING_PERIOD;
 212
 213        device_writel(dev, avg + band, ACTMON_DEV_AVG_UPPER_WMARK);
 214
 215        avg = max(dev->avg_count, band);
 216        device_writel(dev, avg - band, ACTMON_DEV_AVG_LOWER_WMARK);
 217}
 218
 219static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
 220                                       struct tegra_devfreq_device *dev)
 221{
 222        u32 val = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
 223
 224        device_writel(dev, do_percent(val, dev->config->boost_up_threshold),
 225                      ACTMON_DEV_UPPER_WMARK);
 226
 227        device_writel(dev, do_percent(val, dev->config->boost_down_threshold),
 228                      ACTMON_DEV_LOWER_WMARK);
 229}
 230
 231static void actmon_write_barrier(struct tegra_devfreq *tegra)
 232{
 233        /* ensure the update has reached the ACTMON */
 234        wmb();
 235        actmon_readl(tegra, ACTMON_GLB_STATUS);
 236}
 237
 238static void actmon_isr_device(struct tegra_devfreq *tegra,
 239                              struct tegra_devfreq_device *dev)
 240{
 241        unsigned long flags;
 242        u32 intr_status, dev_ctrl;
 243
 244        spin_lock_irqsave(&dev->lock, flags);
 245
 246        dev->avg_count = device_readl(dev, ACTMON_DEV_AVG_COUNT);
 247        tegra_devfreq_update_avg_wmark(tegra, dev);
 248
 249        intr_status = device_readl(dev, ACTMON_DEV_INTR_STATUS);
 250        dev_ctrl = device_readl(dev, ACTMON_DEV_CTRL);
 251
 252        if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_UPPER) {
 253                /*
 254                 * new_boost = min(old_boost * up_coef + step, max_freq)
 255                 */
 256                dev->boost_freq = do_percent(dev->boost_freq,
 257                                             dev->config->boost_up_coeff);
 258                dev->boost_freq += ACTMON_BOOST_FREQ_STEP;
 259
 260                dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 261
 262                if (dev->boost_freq >= tegra->max_freq)
 263                        dev->boost_freq = tegra->max_freq;
 264                else
 265                        dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
 266        } else if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) {
 267                /*
 268                 * new_boost = old_boost * down_coef
 269                 * or 0 if (old_boost * down_coef < step / 2)
 270                 */
 271                dev->boost_freq = do_percent(dev->boost_freq,
 272                                             dev->config->boost_down_coeff);
 273
 274                dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
 275
 276                if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> 1))
 277                        dev->boost_freq = 0;
 278                else
 279                        dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 280        }
 281
 282        if (dev->config->avg_dependency_threshold) {
 283                if (dev->avg_count >= dev->config->avg_dependency_threshold)
 284                        dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 285                else if (dev->boost_freq == 0)
 286                        dev_ctrl &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 287        }
 288
 289        device_writel(dev, dev_ctrl, ACTMON_DEV_CTRL);
 290
 291        device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
 292
 293        actmon_write_barrier(tegra);
 294
 295        spin_unlock_irqrestore(&dev->lock, flags);
 296}
 297
 298static irqreturn_t actmon_isr(int irq, void *data)
 299{
 300        struct tegra_devfreq *tegra = data;
 301        bool handled = false;
 302        unsigned int i;
 303        u32 val;
 304
 305        val = actmon_readl(tegra, ACTMON_GLB_STATUS);
 306        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 307                if (val & tegra->devices[i].config->irq_mask) {
 308                        actmon_isr_device(tegra, tegra->devices + i);
 309                        handled = true;
 310                }
 311        }
 312
 313        return handled ? IRQ_WAKE_THREAD : IRQ_NONE;
 314}
 315
 316static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
 317                                            unsigned long cpu_freq)
 318{
 319        unsigned int i;
 320        struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios;
 321
 322        for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, ratio++) {
 323                if (cpu_freq >= ratio->cpu_freq) {
 324                        if (ratio->emc_freq >= tegra->max_freq)
 325                                return tegra->max_freq;
 326                        else
 327                                return ratio->emc_freq;
 328                }
 329        }
 330
 331        return 0;
 332}
 333
 334static void actmon_update_target(struct tegra_devfreq *tegra,
 335                                 struct tegra_devfreq_device *dev)
 336{
 337        unsigned long cpu_freq = 0;
 338        unsigned long static_cpu_emc_freq = 0;
 339        unsigned int avg_sustain_coef;
 340        unsigned long flags;
 341
 342        if (dev->config->avg_dependency_threshold) {
 343                cpu_freq = cpufreq_get(0);
 344                static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
 345        }
 346
 347        spin_lock_irqsave(&dev->lock, flags);
 348
 349        dev->target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD;
 350        avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
 351        dev->target_freq = do_percent(dev->target_freq, avg_sustain_coef);
 352        dev->target_freq += dev->boost_freq;
 353
 354        if (dev->avg_count >= dev->config->avg_dependency_threshold)
 355                dev->target_freq = max(dev->target_freq, static_cpu_emc_freq);
 356
 357        spin_unlock_irqrestore(&dev->lock, flags);
 358}
 359
 360static irqreturn_t actmon_thread_isr(int irq, void *data)
 361{
 362        struct tegra_devfreq *tegra = data;
 363
 364        mutex_lock(&tegra->devfreq->lock);
 365        update_devfreq(tegra->devfreq);
 366        mutex_unlock(&tegra->devfreq->lock);
 367
 368        return IRQ_HANDLED;
 369}
 370
 371static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
 372                                       unsigned long action, void *ptr)
 373{
 374        struct clk_notifier_data *data = ptr;
 375        struct tegra_devfreq *tegra;
 376        struct tegra_devfreq_device *dev;
 377        unsigned int i;
 378        unsigned long flags;
 379
 380        if (action != POST_RATE_CHANGE)
 381                return NOTIFY_OK;
 382
 383        tegra = container_of(nb, struct tegra_devfreq, rate_change_nb);
 384
 385        tegra->cur_freq = data->new_rate / KHZ;
 386
 387        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 388                dev = &tegra->devices[i];
 389
 390                spin_lock_irqsave(&dev->lock, flags);
 391                tegra_devfreq_update_wmark(tegra, dev);
 392                spin_unlock_irqrestore(&dev->lock, flags);
 393        }
 394
 395        actmon_write_barrier(tegra);
 396
 397        return NOTIFY_OK;
 398}
 399
 400static void tegra_actmon_enable_interrupts(struct tegra_devfreq *tegra)
 401{
 402        struct tegra_devfreq_device *dev;
 403        u32 val;
 404        unsigned int i;
 405
 406        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 407                dev = &tegra->devices[i];
 408
 409                val = device_readl(dev, ACTMON_DEV_CTRL);
 410                val |= ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN;
 411                val |= ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN;
 412                val |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 413                val |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
 414
 415                device_writel(dev, val, ACTMON_DEV_CTRL);
 416        }
 417
 418        actmon_write_barrier(tegra);
 419}
 420
 421static void tegra_actmon_disable_interrupts(struct tegra_devfreq *tegra)
 422{
 423        struct tegra_devfreq_device *dev;
 424        u32 val;
 425        unsigned int i;
 426
 427        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 428                dev = &tegra->devices[i];
 429
 430                val = device_readl(dev, ACTMON_DEV_CTRL);
 431                val &= ~ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN;
 432                val &= ~ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN;
 433                val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 434                val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
 435
 436                device_writel(dev, val, ACTMON_DEV_CTRL);
 437        }
 438
 439        actmon_write_barrier(tegra);
 440}
 441
 442static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
 443                                          struct tegra_devfreq_device *dev)
 444{
 445        u32 val = 0;
 446
 447        dev->target_freq = tegra->cur_freq;
 448
 449        dev->avg_count = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
 450        device_writel(dev, dev->avg_count, ACTMON_DEV_INIT_AVG);
 451
 452        tegra_devfreq_update_avg_wmark(tegra, dev);
 453        tegra_devfreq_update_wmark(tegra, dev);
 454
 455        device_writel(dev, ACTMON_COUNT_WEIGHT, ACTMON_DEV_COUNT_WEIGHT);
 456        device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
 457
 458        val |= ACTMON_DEV_CTRL_ENB_PERIODIC;
 459        val |= (ACTMON_AVERAGE_WINDOW_LOG2 - 1)
 460                << ACTMON_DEV_CTRL_K_VAL_SHIFT;
 461        val |= (ACTMON_BELOW_WMARK_WINDOW - 1)
 462                << ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT;
 463        val |= (ACTMON_ABOVE_WMARK_WINDOW - 1)
 464                << ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT;
 465        val |= ACTMON_DEV_CTRL_ENB;
 466
 467        device_writel(dev, val, ACTMON_DEV_CTRL);
 468
 469        actmon_write_barrier(tegra);
 470}
 471
 472static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
 473                                u32 flags)
 474{
 475        struct tegra_devfreq *tegra = dev_get_drvdata(dev);
 476        struct dev_pm_opp *opp;
 477        unsigned long rate = *freq * KHZ;
 478
 479        opp = devfreq_recommended_opp(dev, &rate, flags);
 480        if (IS_ERR(opp)) {
 481                dev_err(dev, "Failed to find opp for %lu KHz\n", *freq);
 482                return PTR_ERR(opp);
 483        }
 484        rate = dev_pm_opp_get_freq(opp);
 485        dev_pm_opp_put(opp);
 486
 487        clk_set_min_rate(tegra->emc_clock, rate);
 488        clk_set_rate(tegra->emc_clock, 0);
 489
 490        *freq = rate;
 491
 492        return 0;
 493}
 494
 495static int tegra_devfreq_get_dev_status(struct device *dev,
 496                                        struct devfreq_dev_status *stat)
 497{
 498        struct tegra_devfreq *tegra = dev_get_drvdata(dev);
 499        struct tegra_devfreq_device *actmon_dev;
 500
 501        stat->current_frequency = tegra->cur_freq;
 502
 503        /* To be used by the tegra governor */
 504        stat->private_data = tegra;
 505
 506        /* The below are to be used by the other governors */
 507
 508        actmon_dev = &tegra->devices[MCALL];
 509
 510        /* Number of cycles spent on memory access */
 511        stat->busy_time = device_readl(actmon_dev, ACTMON_DEV_AVG_COUNT);
 512
 513        /* The bus can be considered to be saturated way before 100% */
 514        stat->busy_time *= 100 / BUS_SATURATION_RATIO;
 515
 516        /* Number of cycles in a sampling period */
 517        stat->total_time = ACTMON_SAMPLING_PERIOD * tegra->cur_freq;
 518
 519        stat->busy_time = min(stat->busy_time, stat->total_time);
 520
 521        return 0;
 522}
 523
 524static struct devfreq_dev_profile tegra_devfreq_profile = {
 525        .polling_ms     = 0,
 526        .target         = tegra_devfreq_target,
 527        .get_dev_status = tegra_devfreq_get_dev_status,
 528};
 529
 530static int tegra_governor_get_target(struct devfreq *devfreq,
 531                                     unsigned long *freq)
 532{
 533        struct devfreq_dev_status *stat;
 534        struct tegra_devfreq *tegra;
 535        struct tegra_devfreq_device *dev;
 536        unsigned long target_freq = 0;
 537        unsigned int i;
 538        int err;
 539
 540        err = devfreq_update_stats(devfreq);
 541        if (err)
 542                return err;
 543
 544        stat = &devfreq->last_status;
 545
 546        tegra = stat->private_data;
 547
 548        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 549                dev = &tegra->devices[i];
 550
 551                actmon_update_target(tegra, dev);
 552
 553                target_freq = max(target_freq, dev->target_freq);
 554        }
 555
 556        *freq = target_freq;
 557
 558        return 0;
 559}
 560
 561static int tegra_governor_event_handler(struct devfreq *devfreq,
 562                                        unsigned int event, void *data)
 563{
 564        struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
 565
 566        switch (event) {
 567        case DEVFREQ_GOV_START:
 568                devfreq_monitor_start(devfreq);
 569                tegra_actmon_enable_interrupts(tegra);
 570                break;
 571
 572        case DEVFREQ_GOV_STOP:
 573                tegra_actmon_disable_interrupts(tegra);
 574                devfreq_monitor_stop(devfreq);
 575                break;
 576
 577        case DEVFREQ_GOV_SUSPEND:
 578                tegra_actmon_disable_interrupts(tegra);
 579                devfreq_monitor_suspend(devfreq);
 580                break;
 581
 582        case DEVFREQ_GOV_RESUME:
 583                devfreq_monitor_resume(devfreq);
 584                tegra_actmon_enable_interrupts(tegra);
 585                break;
 586        }
 587
 588        return 0;
 589}
 590
 591static struct devfreq_governor tegra_devfreq_governor = {
 592        .name = "tegra_actmon",
 593        .get_target_freq = tegra_governor_get_target,
 594        .event_handler = tegra_governor_event_handler,
 595};
 596
 597static int tegra_devfreq_probe(struct platform_device *pdev)
 598{
 599        struct tegra_devfreq *tegra;
 600        struct tegra_devfreq_device *dev;
 601        struct resource *res;
 602        unsigned int i;
 603        unsigned long rate;
 604        int irq;
 605        int err;
 606
 607        tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
 608        if (!tegra)
 609                return -ENOMEM;
 610
 611        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 612
 613        tegra->regs = devm_ioremap_resource(&pdev->dev, res);
 614        if (IS_ERR(tegra->regs))
 615                return PTR_ERR(tegra->regs);
 616
 617        tegra->reset = devm_reset_control_get(&pdev->dev, "actmon");
 618        if (IS_ERR(tegra->reset)) {
 619                dev_err(&pdev->dev, "Failed to get reset\n");
 620                return PTR_ERR(tegra->reset);
 621        }
 622
 623        tegra->clock = devm_clk_get(&pdev->dev, "actmon");
 624        if (IS_ERR(tegra->clock)) {
 625                dev_err(&pdev->dev, "Failed to get actmon clock\n");
 626                return PTR_ERR(tegra->clock);
 627        }
 628
 629        tegra->emc_clock = devm_clk_get(&pdev->dev, "emc");
 630        if (IS_ERR(tegra->emc_clock)) {
 631                dev_err(&pdev->dev, "Failed to get emc clock\n");
 632                return PTR_ERR(tegra->emc_clock);
 633        }
 634
 635        clk_set_rate(tegra->emc_clock, ULONG_MAX);
 636
 637        tegra->rate_change_nb.notifier_call = tegra_actmon_rate_notify_cb;
 638        err = clk_notifier_register(tegra->emc_clock, &tegra->rate_change_nb);
 639        if (err) {
 640                dev_err(&pdev->dev,
 641                        "Failed to register rate change notifier\n");
 642                return err;
 643        }
 644
 645        reset_control_assert(tegra->reset);
 646
 647        err = clk_prepare_enable(tegra->clock);
 648        if (err) {
 649                dev_err(&pdev->dev,
 650                        "Failed to prepare and enable ACTMON clock\n");
 651                return err;
 652        }
 653
 654        reset_control_deassert(tegra->reset);
 655
 656        tegra->max_freq = clk_round_rate(tegra->emc_clock, ULONG_MAX) / KHZ;
 657        tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ;
 658
 659        actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1,
 660                      ACTMON_GLB_PERIOD_CTRL);
 661
 662        for (i = 0; i < ARRAY_SIZE(actmon_device_configs); i++) {
 663                dev = tegra->devices + i;
 664                dev->config = actmon_device_configs + i;
 665                dev->regs = tegra->regs + dev->config->offset;
 666                spin_lock_init(&dev->lock);
 667
 668                tegra_actmon_configure_device(tegra, dev);
 669        }
 670
 671        for (rate = 0; rate <= tegra->max_freq * KHZ; rate++) {
 672                rate = clk_round_rate(tegra->emc_clock, rate);
 673                dev_pm_opp_add(&pdev->dev, rate, 0);
 674        }
 675
 676        irq = platform_get_irq(pdev, 0);
 677        if (irq < 0) {
 678                dev_err(&pdev->dev, "Failed to get IRQ: %d\n", irq);
 679                return irq;
 680        }
 681
 682        platform_set_drvdata(pdev, tegra);
 683
 684        err = devm_request_threaded_irq(&pdev->dev, irq, actmon_isr,
 685                                        actmon_thread_isr, IRQF_SHARED,
 686                                        "tegra-devfreq", tegra);
 687        if (err) {
 688                dev_err(&pdev->dev, "Interrupt request failed\n");
 689                return err;
 690        }
 691
 692        tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
 693        tegra->devfreq = devm_devfreq_add_device(&pdev->dev,
 694                                                 &tegra_devfreq_profile,
 695                                                 "tegra_actmon",
 696                                                 NULL);
 697
 698        return 0;
 699}
 700
 701static int tegra_devfreq_remove(struct platform_device *pdev)
 702{
 703        struct tegra_devfreq *tegra = platform_get_drvdata(pdev);
 704        int irq = platform_get_irq(pdev, 0);
 705        u32 val;
 706        unsigned int i;
 707
 708        for (i = 0; i < ARRAY_SIZE(actmon_device_configs); i++) {
 709                val = device_readl(&tegra->devices[i], ACTMON_DEV_CTRL);
 710                val &= ~ACTMON_DEV_CTRL_ENB;
 711                device_writel(&tegra->devices[i], val, ACTMON_DEV_CTRL);
 712        }
 713
 714        actmon_write_barrier(tegra);
 715
 716        devm_free_irq(&pdev->dev, irq, tegra);
 717
 718        clk_notifier_unregister(tegra->emc_clock, &tegra->rate_change_nb);
 719
 720        clk_disable_unprepare(tegra->clock);
 721
 722        return 0;
 723}
 724
 725static const struct of_device_id tegra_devfreq_of_match[] = {
 726        { .compatible = "nvidia,tegra124-actmon" },
 727        { },
 728};
 729
 730MODULE_DEVICE_TABLE(of, tegra_devfreq_of_match);
 731
 732static struct platform_driver tegra_devfreq_driver = {
 733        .probe  = tegra_devfreq_probe,
 734        .remove = tegra_devfreq_remove,
 735        .driver = {
 736                .name = "tegra-devfreq",
 737                .of_match_table = tegra_devfreq_of_match,
 738        },
 739};
 740
 741static int __init tegra_devfreq_init(void)
 742{
 743        int ret = 0;
 744
 745        ret = devfreq_add_governor(&tegra_devfreq_governor);
 746        if (ret) {
 747                pr_err("%s: failed to add governor: %d\n", __func__, ret);
 748                return ret;
 749        }
 750
 751        ret = platform_driver_register(&tegra_devfreq_driver);
 752        if (ret)
 753                devfreq_remove_governor(&tegra_devfreq_governor);
 754
 755        return ret;
 756}
 757module_init(tegra_devfreq_init)
 758
 759static void __exit tegra_devfreq_exit(void)
 760{
 761        int ret = 0;
 762
 763        platform_driver_unregister(&tegra_devfreq_driver);
 764
 765        ret = devfreq_remove_governor(&tegra_devfreq_governor);
 766        if (ret)
 767                pr_err("%s: failed to remove governor: %d\n", __func__, ret);
 768}
 769module_exit(tegra_devfreq_exit)
 770
 771MODULE_LICENSE("GPL v2");
 772MODULE_DESCRIPTION("Tegra devfreq driver");
 773MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>");
 774