linux/drivers/devfreq/tegra-devfreq.c
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   1/*
   2 * A devfreq driver for NVIDIA Tegra SoCs
   3 *
   4 * Copyright (c) 2014 NVIDIA CORPORATION. All rights reserved.
   5 * Copyright (C) 2014 Google, Inc
   6 *
   7 * This program is free software; you can redistribute it and/or modify it
   8 * under the terms and conditions of the GNU General Public License,
   9 * version 2, as published by the Free Software Foundation.
  10 *
  11 * This program is distributed in the hope it will be useful, but WITHOUT
  12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  14 * more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
  18 *
  19 */
  20
  21#include <linux/clk.h>
  22#include <linux/cpufreq.h>
  23#include <linux/devfreq.h>
  24#include <linux/interrupt.h>
  25#include <linux/io.h>
  26#include <linux/module.h>
  27#include <linux/platform_device.h>
  28#include <linux/pm_opp.h>
  29#include <linux/reset.h>
  30
  31#include "governor.h"
  32
  33#define ACTMON_GLB_STATUS                                       0x0
  34#define ACTMON_GLB_PERIOD_CTRL                                  0x4
  35
  36#define ACTMON_DEV_CTRL                                         0x0
  37#define ACTMON_DEV_CTRL_K_VAL_SHIFT                             10
  38#define ACTMON_DEV_CTRL_ENB_PERIODIC                            BIT(18)
  39#define ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN                      BIT(20)
  40#define ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN                      BIT(21)
  41#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT       23
  42#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT       26
  43#define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN              BIT(29)
  44#define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN              BIT(30)
  45#define ACTMON_DEV_CTRL_ENB                                     BIT(31)
  46
  47#define ACTMON_DEV_UPPER_WMARK                                  0x4
  48#define ACTMON_DEV_LOWER_WMARK                                  0x8
  49#define ACTMON_DEV_INIT_AVG                                     0xc
  50#define ACTMON_DEV_AVG_UPPER_WMARK                              0x10
  51#define ACTMON_DEV_AVG_LOWER_WMARK                              0x14
  52#define ACTMON_DEV_COUNT_WEIGHT                                 0x18
  53#define ACTMON_DEV_AVG_COUNT                                    0x20
  54#define ACTMON_DEV_INTR_STATUS                                  0x24
  55
  56#define ACTMON_INTR_STATUS_CLEAR                                0xffffffff
  57
  58#define ACTMON_DEV_INTR_CONSECUTIVE_UPPER                       BIT(31)
  59#define ACTMON_DEV_INTR_CONSECUTIVE_LOWER                       BIT(30)
  60
  61#define ACTMON_ABOVE_WMARK_WINDOW                               1
  62#define ACTMON_BELOW_WMARK_WINDOW                               3
  63#define ACTMON_BOOST_FREQ_STEP                                  16000
  64
  65/* activity counter is incremented every 256 memory transactions, and each
  66 * transaction takes 4 EMC clocks for Tegra124; So the COUNT_WEIGHT is
  67 * 4 * 256 = 1024.
  68 */
  69#define ACTMON_COUNT_WEIGHT                                     0x400
  70
  71/*
  72 * ACTMON_AVERAGE_WINDOW_LOG2: default value for @DEV_CTRL_K_VAL, which
  73 * translates to 2 ^ (K_VAL + 1). ex: 2 ^ (6 + 1) = 128
  74 */
  75#define ACTMON_AVERAGE_WINDOW_LOG2                      6
  76#define ACTMON_SAMPLING_PERIOD                          12 /* ms */
  77#define ACTMON_DEFAULT_AVG_BAND                         6  /* 1/10 of % */
  78
  79#define KHZ                                                     1000
  80
  81/* Assume that the bus is saturated if the utilization is 25% */
  82#define BUS_SATURATION_RATIO                                    25
  83
  84/**
  85 * struct tegra_devfreq_device_config - configuration specific to an ACTMON
  86 * device
  87 *
  88 * Coefficients and thresholds are in %
  89 */
  90struct tegra_devfreq_device_config {
  91        u32             offset;
  92        u32             irq_mask;
  93
  94        unsigned int    boost_up_coeff;
  95        unsigned int    boost_down_coeff;
  96        unsigned int    boost_up_threshold;
  97        unsigned int    boost_down_threshold;
  98        u32             avg_dependency_threshold;
  99};
 100
 101enum tegra_actmon_device {
 102        MCALL = 0,
 103        MCCPU,
 104};
 105
 106static struct tegra_devfreq_device_config actmon_device_configs[] = {
 107        {
 108                /* MCALL */
 109                .offset = 0x1c0,
 110                .irq_mask = 1 << 26,
 111                .boost_up_coeff = 200,
 112                .boost_down_coeff = 50,
 113                .boost_up_threshold = 60,
 114                .boost_down_threshold = 40,
 115        },
 116        {
 117                /* MCCPU */
 118                .offset = 0x200,
 119                .irq_mask = 1 << 25,
 120                .boost_up_coeff = 800,
 121                .boost_down_coeff = 90,
 122                .boost_up_threshold = 27,
 123                .boost_down_threshold = 10,
 124                .avg_dependency_threshold = 50000,
 125        },
 126};
 127
 128/**
 129 * struct tegra_devfreq_device - state specific to an ACTMON device
 130 *
 131 * Frequencies are in kHz.
 132 */
 133struct tegra_devfreq_device {
 134        const struct tegra_devfreq_device_config *config;
 135
 136        void __iomem    *regs;
 137        u32             avg_band_freq;
 138        u32             avg_count;
 139
 140        unsigned long   target_freq;
 141        unsigned long   boost_freq;
 142};
 143
 144struct tegra_devfreq {
 145        struct devfreq          *devfreq;
 146
 147        struct platform_device  *pdev;
 148        struct reset_control    *reset;
 149        struct clk              *clock;
 150        void __iomem            *regs;
 151
 152        spinlock_t              lock;
 153
 154        struct clk              *emc_clock;
 155        unsigned long           max_freq;
 156        unsigned long           cur_freq;
 157        struct notifier_block   rate_change_nb;
 158
 159        struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
 160};
 161
 162struct tegra_actmon_emc_ratio {
 163        unsigned long cpu_freq;
 164        unsigned long emc_freq;
 165};
 166
 167static struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
 168        { 1400000, ULONG_MAX },
 169        { 1200000,    750000 },
 170        { 1100000,    600000 },
 171        { 1000000,    500000 },
 172        {  800000,    375000 },
 173        {  500000,    200000 },
 174        {  250000,    100000 },
 175};
 176
 177static unsigned long do_percent(unsigned long val, unsigned int pct)
 178{
 179        return val * pct / 100;
 180}
 181
 182static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq_device *dev)
 183{
 184        u32 avg = dev->avg_count;
 185        u32 band = dev->avg_band_freq * ACTMON_SAMPLING_PERIOD;
 186
 187        writel(avg + band, dev->regs + ACTMON_DEV_AVG_UPPER_WMARK);
 188        avg = max(avg, band);
 189        writel(avg - band, dev->regs + ACTMON_DEV_AVG_LOWER_WMARK);
 190}
 191
 192static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
 193                                       struct tegra_devfreq_device *dev)
 194{
 195        u32 val = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
 196
 197        writel(do_percent(val, dev->config->boost_up_threshold),
 198               dev->regs + ACTMON_DEV_UPPER_WMARK);
 199
 200        writel(do_percent(val, dev->config->boost_down_threshold),
 201               dev->regs + ACTMON_DEV_LOWER_WMARK);
 202}
 203
 204static void actmon_write_barrier(struct tegra_devfreq *tegra)
 205{
 206        /* ensure the update has reached the ACTMON */
 207        wmb();
 208        readl(tegra->regs + ACTMON_GLB_STATUS);
 209}
 210
 211static irqreturn_t actmon_isr(int irq, void *data)
 212{
 213        struct tegra_devfreq *tegra = data;
 214        struct tegra_devfreq_device *dev = NULL;
 215        unsigned long flags;
 216        u32 val;
 217        unsigned int i;
 218
 219        val = readl(tegra->regs + ACTMON_GLB_STATUS);
 220
 221        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 222                if (val & tegra->devices[i].config->irq_mask) {
 223                        dev = tegra->devices + i;
 224                        break;
 225                }
 226        }
 227
 228        if (!dev)
 229                return IRQ_NONE;
 230
 231        spin_lock_irqsave(&tegra->lock, flags);
 232
 233        dev->avg_count = readl(dev->regs + ACTMON_DEV_AVG_COUNT);
 234        tegra_devfreq_update_avg_wmark(dev);
 235
 236        val = readl(dev->regs + ACTMON_DEV_INTR_STATUS);
 237        if (val & ACTMON_DEV_INTR_CONSECUTIVE_UPPER) {
 238                val = readl(dev->regs + ACTMON_DEV_CTRL) |
 239                        ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN |
 240                        ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 241
 242                /*
 243                 * new_boost = min(old_boost * up_coef + step, max_freq)
 244                 */
 245                dev->boost_freq = do_percent(dev->boost_freq,
 246                                             dev->config->boost_up_coeff);
 247                dev->boost_freq += ACTMON_BOOST_FREQ_STEP;
 248                if (dev->boost_freq >= tegra->max_freq) {
 249                        dev->boost_freq = tegra->max_freq;
 250                        val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
 251                }
 252                writel(val, dev->regs + ACTMON_DEV_CTRL);
 253        } else if (val & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) {
 254                val = readl(dev->regs + ACTMON_DEV_CTRL) |
 255                        ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN |
 256                        ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 257
 258                /*
 259                 * new_boost = old_boost * down_coef
 260                 * or 0 if (old_boost * down_coef < step / 2)
 261                 */
 262                dev->boost_freq = do_percent(dev->boost_freq,
 263                                             dev->config->boost_down_coeff);
 264                if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> 1)) {
 265                        dev->boost_freq = 0;
 266                        val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 267                }
 268                writel(val, dev->regs + ACTMON_DEV_CTRL);
 269        }
 270
 271        if (dev->config->avg_dependency_threshold) {
 272                val = readl(dev->regs + ACTMON_DEV_CTRL);
 273                if (dev->avg_count >= dev->config->avg_dependency_threshold)
 274                        val |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 275                else if (dev->boost_freq == 0)
 276                        val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
 277                writel(val, dev->regs + ACTMON_DEV_CTRL);
 278        }
 279
 280        writel(ACTMON_INTR_STATUS_CLEAR, dev->regs + ACTMON_DEV_INTR_STATUS);
 281
 282        actmon_write_barrier(tegra);
 283
 284        spin_unlock_irqrestore(&tegra->lock, flags);
 285
 286        return IRQ_WAKE_THREAD;
 287}
 288
 289static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
 290                                            unsigned long cpu_freq)
 291{
 292        unsigned int i;
 293        struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios;
 294
 295        for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, ratio++) {
 296                if (cpu_freq >= ratio->cpu_freq) {
 297                        if (ratio->emc_freq >= tegra->max_freq)
 298                                return tegra->max_freq;
 299                        else
 300                                return ratio->emc_freq;
 301                }
 302        }
 303
 304        return 0;
 305}
 306
 307static void actmon_update_target(struct tegra_devfreq *tegra,
 308                                 struct tegra_devfreq_device *dev)
 309{
 310        unsigned long cpu_freq = 0;
 311        unsigned long static_cpu_emc_freq = 0;
 312        unsigned int avg_sustain_coef;
 313        unsigned long flags;
 314
 315        if (dev->config->avg_dependency_threshold) {
 316                cpu_freq = cpufreq_get(0);
 317                static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
 318        }
 319
 320        spin_lock_irqsave(&tegra->lock, flags);
 321
 322        dev->target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD;
 323        avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
 324        dev->target_freq = do_percent(dev->target_freq, avg_sustain_coef);
 325        dev->target_freq += dev->boost_freq;
 326
 327        if (dev->avg_count >= dev->config->avg_dependency_threshold)
 328                dev->target_freq = max(dev->target_freq, static_cpu_emc_freq);
 329
 330        spin_unlock_irqrestore(&tegra->lock, flags);
 331}
 332
 333static irqreturn_t actmon_thread_isr(int irq, void *data)
 334{
 335        struct tegra_devfreq *tegra = data;
 336
 337        mutex_lock(&tegra->devfreq->lock);
 338        update_devfreq(tegra->devfreq);
 339        mutex_unlock(&tegra->devfreq->lock);
 340
 341        return IRQ_HANDLED;
 342}
 343
 344static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
 345                                       unsigned long action, void *ptr)
 346{
 347        struct clk_notifier_data *data = ptr;
 348        struct tegra_devfreq *tegra = container_of(nb, struct tegra_devfreq,
 349                                                   rate_change_nb);
 350        unsigned int i;
 351        unsigned long flags;
 352
 353        spin_lock_irqsave(&tegra->lock, flags);
 354
 355        switch (action) {
 356        case POST_RATE_CHANGE:
 357                tegra->cur_freq = data->new_rate / KHZ;
 358
 359                for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
 360                        tegra_devfreq_update_wmark(tegra, tegra->devices + i);
 361
 362                actmon_write_barrier(tegra);
 363                break;
 364        case PRE_RATE_CHANGE:
 365                /* fall through */
 366        case ABORT_RATE_CHANGE:
 367                break;
 368        };
 369
 370        spin_unlock_irqrestore(&tegra->lock, flags);
 371
 372        return NOTIFY_OK;
 373}
 374
 375static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
 376                                          struct tegra_devfreq_device *dev)
 377{
 378        u32 val;
 379
 380        dev->avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
 381        dev->target_freq = tegra->cur_freq;
 382
 383        dev->avg_count = tegra->cur_freq * ACTMON_SAMPLING_PERIOD;
 384        writel(dev->avg_count, dev->regs + ACTMON_DEV_INIT_AVG);
 385
 386        tegra_devfreq_update_avg_wmark(dev);
 387        tegra_devfreq_update_wmark(tegra, dev);
 388
 389        writel(ACTMON_COUNT_WEIGHT, dev->regs + ACTMON_DEV_COUNT_WEIGHT);
 390        writel(ACTMON_INTR_STATUS_CLEAR, dev->regs + ACTMON_DEV_INTR_STATUS);
 391
 392        val = 0;
 393        val |= ACTMON_DEV_CTRL_ENB_PERIODIC |
 394               ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN |
 395               ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN;
 396        val |= (ACTMON_AVERAGE_WINDOW_LOG2 - 1)
 397                << ACTMON_DEV_CTRL_K_VAL_SHIFT;
 398        val |= (ACTMON_BELOW_WMARK_WINDOW - 1)
 399                << ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT;
 400        val |= (ACTMON_ABOVE_WMARK_WINDOW - 1)
 401                << ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT;
 402        val |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN |
 403               ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
 404
 405        writel(val, dev->regs + ACTMON_DEV_CTRL);
 406
 407        actmon_write_barrier(tegra);
 408
 409        val = readl(dev->regs + ACTMON_DEV_CTRL);
 410        val |= ACTMON_DEV_CTRL_ENB;
 411        writel(val, dev->regs + ACTMON_DEV_CTRL);
 412
 413        actmon_write_barrier(tegra);
 414}
 415
 416static int tegra_devfreq_suspend(struct device *dev)
 417{
 418        struct platform_device *pdev;
 419        struct tegra_devfreq *tegra;
 420        struct tegra_devfreq_device *actmon_dev;
 421        unsigned int i;
 422        u32 val;
 423
 424        pdev = container_of(dev, struct platform_device, dev);
 425        tegra = platform_get_drvdata(pdev);
 426
 427        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 428                actmon_dev = &tegra->devices[i];
 429
 430                val = readl(actmon_dev->regs + ACTMON_DEV_CTRL);
 431                val &= ~ACTMON_DEV_CTRL_ENB;
 432                writel(val, actmon_dev->regs + ACTMON_DEV_CTRL);
 433
 434                writel(ACTMON_INTR_STATUS_CLEAR,
 435                       actmon_dev->regs + ACTMON_DEV_INTR_STATUS);
 436
 437                actmon_write_barrier(tegra);
 438        }
 439
 440        return 0;
 441}
 442
 443static int tegra_devfreq_resume(struct device *dev)
 444{
 445        struct platform_device *pdev;
 446        struct tegra_devfreq *tegra;
 447        struct tegra_devfreq_device *actmon_dev;
 448        unsigned int i;
 449
 450        pdev = container_of(dev, struct platform_device, dev);
 451        tegra = platform_get_drvdata(pdev);
 452
 453        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 454                actmon_dev = &tegra->devices[i];
 455
 456                tegra_actmon_configure_device(tegra, actmon_dev);
 457        }
 458
 459        return 0;
 460}
 461
 462static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
 463                                u32 flags)
 464{
 465        struct platform_device *pdev;
 466        struct tegra_devfreq *tegra;
 467        struct dev_pm_opp *opp;
 468        unsigned long rate = *freq * KHZ;
 469
 470        pdev = container_of(dev, struct platform_device, dev);
 471        tegra = platform_get_drvdata(pdev);
 472
 473        rcu_read_lock();
 474        opp = devfreq_recommended_opp(dev, &rate, flags);
 475        if (IS_ERR(opp)) {
 476                rcu_read_unlock();
 477                dev_err(dev, "Failed to find opp for %lu KHz\n", *freq);
 478                return PTR_ERR(opp);
 479        }
 480        rate = dev_pm_opp_get_freq(opp);
 481        rcu_read_unlock();
 482
 483        /* TODO: Once we have per-user clk constraints, set a floor */
 484        clk_set_rate(tegra->emc_clock, rate);
 485
 486        /* TODO: Set voltage as well */
 487
 488        return 0;
 489}
 490
 491static int tegra_devfreq_get_dev_status(struct device *dev,
 492                                        struct devfreq_dev_status *stat)
 493{
 494        struct platform_device *pdev;
 495        struct tegra_devfreq *tegra;
 496        struct tegra_devfreq_device *actmon_dev;
 497
 498        pdev = container_of(dev, struct platform_device, dev);
 499        tegra = platform_get_drvdata(pdev);
 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 = 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        return 0;
 520}
 521
 522static int tegra_devfreq_get_target(struct devfreq *devfreq,
 523                                    unsigned long *freq)
 524{
 525        struct devfreq_dev_status stat;
 526        struct tegra_devfreq *tegra;
 527        struct tegra_devfreq_device *dev;
 528        unsigned long target_freq = 0;
 529        unsigned int i;
 530        int err;
 531
 532        err = devfreq->profile->get_dev_status(devfreq->dev.parent, &stat);
 533        if (err)
 534                return err;
 535
 536        tegra = stat.private_data;
 537
 538        for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 539                dev = &tegra->devices[i];
 540
 541                actmon_update_target(tegra, dev);
 542
 543                target_freq = max(target_freq, dev->target_freq);
 544        }
 545
 546        *freq = target_freq;
 547
 548        return 0;
 549}
 550
 551static int tegra_devfreq_event_handler(struct devfreq *devfreq,
 552                                       unsigned int event, void *data)
 553{
 554        return 0;
 555}
 556
 557static struct devfreq_governor tegra_devfreq_governor = {
 558        .name = "tegra",
 559        .get_target_freq = tegra_devfreq_get_target,
 560        .event_handler = tegra_devfreq_event_handler,
 561};
 562
 563static struct devfreq_dev_profile tegra_devfreq_profile = {
 564        .polling_ms     = 0,
 565        .target         = tegra_devfreq_target,
 566        .get_dev_status = tegra_devfreq_get_dev_status,
 567};
 568
 569static int tegra_devfreq_probe(struct platform_device *pdev)
 570{
 571        struct tegra_devfreq *tegra;
 572        struct tegra_devfreq_device *dev;
 573        struct resource *res;
 574        unsigned long max_freq;
 575        unsigned int i;
 576        int irq;
 577        int err;
 578
 579        tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
 580        if (!tegra)
 581                return -ENOMEM;
 582
 583        spin_lock_init(&tegra->lock);
 584
 585        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 586        if (!res) {
 587                dev_err(&pdev->dev, "Failed to get regs resource\n");
 588                return -ENODEV;
 589        }
 590
 591        tegra->regs = devm_ioremap_resource(&pdev->dev, res);
 592        if (IS_ERR(tegra->regs)) {
 593                dev_err(&pdev->dev, "Failed to get IO memory\n");
 594                return PTR_ERR(tegra->regs);
 595        }
 596
 597        tegra->reset = devm_reset_control_get(&pdev->dev, "actmon");
 598        if (IS_ERR(tegra->reset)) {
 599                dev_err(&pdev->dev, "Failed to get reset\n");
 600                return PTR_ERR(tegra->reset);
 601        }
 602
 603        tegra->clock = devm_clk_get(&pdev->dev, "actmon");
 604        if (IS_ERR(tegra->clock)) {
 605                dev_err(&pdev->dev, "Failed to get actmon clock\n");
 606                return PTR_ERR(tegra->clock);
 607        }
 608
 609        tegra->emc_clock = devm_clk_get(&pdev->dev, "emc");
 610        if (IS_ERR(tegra->emc_clock)) {
 611                dev_err(&pdev->dev, "Failed to get emc clock\n");
 612                return PTR_ERR(tegra->emc_clock);
 613        }
 614
 615        err = of_init_opp_table(&pdev->dev);
 616        if (err) {
 617                dev_err(&pdev->dev, "Failed to init operating point table\n");
 618                return err;
 619        }
 620
 621        tegra->rate_change_nb.notifier_call = tegra_actmon_rate_notify_cb;
 622        err = clk_notifier_register(tegra->emc_clock, &tegra->rate_change_nb);
 623        if (err) {
 624                dev_err(&pdev->dev,
 625                        "Failed to register rate change notifier\n");
 626                return err;
 627        }
 628
 629        reset_control_assert(tegra->reset);
 630
 631        err = clk_prepare_enable(tegra->clock);
 632        if (err) {
 633                reset_control_deassert(tegra->reset);
 634                return err;
 635        }
 636
 637        reset_control_deassert(tegra->reset);
 638
 639        max_freq = clk_round_rate(tegra->emc_clock, ULONG_MAX);
 640        tegra->max_freq = max_freq / KHZ;
 641
 642        clk_set_rate(tegra->emc_clock, max_freq);
 643
 644        tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ;
 645
 646        writel(ACTMON_SAMPLING_PERIOD - 1,
 647               tegra->regs + ACTMON_GLB_PERIOD_CTRL);
 648
 649        for (i = 0; i < ARRAY_SIZE(actmon_device_configs); i++) {
 650                dev = tegra->devices + i;
 651                dev->config = actmon_device_configs + i;
 652                dev->regs = tegra->regs + dev->config->offset;
 653
 654                tegra_actmon_configure_device(tegra, tegra->devices + i);
 655        }
 656
 657        err = devfreq_add_governor(&tegra_devfreq_governor);
 658        if (err) {
 659                dev_err(&pdev->dev, "Failed to add governor\n");
 660                return err;
 661        }
 662
 663        tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
 664        tegra->devfreq = devm_devfreq_add_device(&pdev->dev,
 665                                                 &tegra_devfreq_profile,
 666                                                 "tegra",
 667                                                 NULL);
 668
 669        irq = platform_get_irq(pdev, 0);
 670        err = devm_request_threaded_irq(&pdev->dev, irq, actmon_isr,
 671                                        actmon_thread_isr, IRQF_SHARED,
 672                                        "tegra-devfreq", tegra);
 673        if (err) {
 674                dev_err(&pdev->dev, "Interrupt request failed\n");
 675                return err;
 676        }
 677
 678        platform_set_drvdata(pdev, tegra);
 679
 680        return 0;
 681}
 682
 683static int tegra_devfreq_remove(struct platform_device *pdev)
 684{
 685        struct tegra_devfreq *tegra = platform_get_drvdata(pdev);
 686
 687        clk_notifier_unregister(tegra->emc_clock, &tegra->rate_change_nb);
 688
 689        clk_disable_unprepare(tegra->clock);
 690
 691        return 0;
 692}
 693
 694static SIMPLE_DEV_PM_OPS(tegra_devfreq_pm_ops,
 695                         tegra_devfreq_suspend,
 696                         tegra_devfreq_resume);
 697
 698static struct of_device_id tegra_devfreq_of_match[] = {
 699        { .compatible = "nvidia,tegra124-actmon" },
 700        { },
 701};
 702
 703static struct platform_driver tegra_devfreq_driver = {
 704        .probe  = tegra_devfreq_probe,
 705        .remove = tegra_devfreq_remove,
 706        .driver = {
 707                .name           = "tegra-devfreq",
 708                .owner          = THIS_MODULE,
 709                .of_match_table = tegra_devfreq_of_match,
 710                .pm             = &tegra_devfreq_pm_ops,
 711        },
 712};
 713module_platform_driver(tegra_devfreq_driver);
 714
 715MODULE_LICENSE("GPL");
 716MODULE_DESCRIPTION("Tegra devfreq driver");
 717MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>");
 718MODULE_DEVICE_TABLE(of, tegra_devfreq_of_match);
 719