drivers/devfreq/tegra-devfreq.c

   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  */
  80 struct 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
 100 enum tegra_actmon_device {
 101         MCALL = 0,
 102         MCCPU,
 103 };
 104
 105 static 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  */
 132 struct 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
 150 struct 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
 165 struct tegra_actmon_emc_ratio {
 166         unsigned long cpu_freq;
 167         unsigned long emc_freq;
 168 };
 169
 170 static 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
 180 static u32 actmon_readl(struct tegra_devfreq *tegra, u32 offset)
 181 {
 182         return readl(tegra->regs + offset);
 183 }
 184
 185 static void actmon_writel(struct tegra_devfreq *tegra, u32 val, u32 offset)
 186 {
 187         writel(val, tegra->regs + offset);
 188 }
 189
 190 static u32 device_readl(struct tegra_devfreq_device *dev, u32 offset)
 191 {
 192         return readl(dev->regs + offset);
 193 }
 194
 195 static void device_writel(struct tegra_devfreq_device *dev, u32 val,
 196                           u32 offset)
 197 {
 198         writel(val, dev->regs + offset);
 199 }
 200
 201 static unsigned long do_percent(unsigned long val, unsigned int pct)
 202 {
 203         return val * pct / 100;
 204 }
 205
 206 static 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
 219 static 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
 231 static 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
 238 static 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
 298 static 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
 316 static 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
 334 static 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
 360 static 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
 371 static 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
 400 static 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
 421 static 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
 442 static 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
 472 static 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
 495 static 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
 524 static 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
 530 static 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
 561 static 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
 591 static 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
 597 static 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
 701 static 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
 725 static const struct of_device_id tegra_devfreq_of_match[] = {
 726         { .compatible = "nvidia,tegra124-actmon" },
 727         { },
 728 };
 729
 730 MODULE_DEVICE_TABLE(of, tegra_devfreq_of_match);
 731
 732 static 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
 741 static 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 }
 757 module_init(tegra_devfreq_init)
 758
 759 static 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 }
 769 module_exit(tegra_devfreq_exit)
 770
 771 MODULE_LICENSE("GPL v2");
 772 MODULE_DESCRIPTION("Tegra devfreq driver");
 773 MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>");