drivers/devfreq/exynos-bus.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Generic Exynos Bus frequency driver with DEVFREQ Framework
   4  *
   5  * Copyright (c) 2016 Samsung Electronics Co., Ltd.
   6  * Author : Chanwoo Choi <cw00.choi@samsung.com>
   7  *
   8  * This driver support Exynos Bus frequency feature by using
   9  * DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c.
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/devfreq.h>
  14 #include <linux/devfreq-event.h>
  15 #include <linux/device.h>
  16 #include <linux/export.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/pm_opp.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/regulator/consumer.h>
  22
  23 #define DEFAULT_SATURATION_RATIO        40
  24
  25 struct exynos_bus {
  26         struct device *dev;
  27         struct platform_device *icc_pdev;
  28
  29         struct devfreq *devfreq;
  30         struct devfreq_event_dev **edev;
  31         unsigned int edev_count;
  32         struct mutex lock;
  33
  34         unsigned long curr_freq;
  35
  36         struct opp_table *opp_table;
  37         struct clk *clk;
  38         unsigned int ratio;
  39 };
  40
  41 /*
  42  * Control the devfreq-event device to get the current state of bus
  43  */
  44 #define exynos_bus_ops_edev(ops)                                \
  45 static int exynos_bus_##ops(struct exynos_bus *bus)             \
  46 {                                                               \
  47         int i, ret;                                             \
  48                                                                 \
  49         for (i = 0; i < bus->edev_count; i++) {                 \
  50                 if (!bus->edev[i])                              \
  51                         continue;                               \
  52                 ret = devfreq_event_##ops(bus->edev[i]);        \
  53                 if (ret < 0)                                    \
  54                         return ret;                             \
  55         }                                                       \
  56                                                                 \
  57         return 0;                                               \
  58 }
  59 exynos_bus_ops_edev(enable_edev);
  60 exynos_bus_ops_edev(disable_edev);
  61 exynos_bus_ops_edev(set_event);
  62
  63 static int exynos_bus_get_event(struct exynos_bus *bus,
  64                                 struct devfreq_event_data *edata)
  65 {
  66         struct devfreq_event_data event_data;
  67         unsigned long load_count = 0, total_count = 0;
  68         int i, ret = 0;
  69
  70         for (i = 0; i < bus->edev_count; i++) {
  71                 if (!bus->edev[i])
  72                         continue;
  73
  74                 ret = devfreq_event_get_event(bus->edev[i], &event_data);
  75                 if (ret < 0)
  76                         return ret;
  77
  78                 if (i == 0 || event_data.load_count > load_count) {
  79                         load_count = event_data.load_count;
  80                         total_count = event_data.total_count;
  81                 }
  82         }
  83
  84         edata->load_count = load_count;
  85         edata->total_count = total_count;
  86
  87         return ret;
  88 }
  89
  90 /*
  91  * devfreq function for both simple-ondemand and passive governor
  92  */
  93 static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
  94 {
  95         struct exynos_bus *bus = dev_get_drvdata(dev);
  96         struct dev_pm_opp *new_opp;
  97         int ret = 0;
  98
  99         /* Get correct frequency for bus. */
 100         new_opp = devfreq_recommended_opp(dev, freq, flags);
 101         if (IS_ERR(new_opp)) {
 102                 dev_err(dev, "failed to get recommended opp instance\n");
 103                 return PTR_ERR(new_opp);
 104         }
 105
 106         dev_pm_opp_put(new_opp);
 107
 108         /* Change voltage and frequency according to new OPP level */
 109         mutex_lock(&bus->lock);
 110         ret = dev_pm_opp_set_rate(dev, *freq);
 111         if (!ret)
 112                 bus->curr_freq = *freq;
 113
 114         mutex_unlock(&bus->lock);
 115
 116         return ret;
 117 }
 118
 119 static int exynos_bus_get_dev_status(struct device *dev,
 120                                      struct devfreq_dev_status *stat)
 121 {
 122         struct exynos_bus *bus = dev_get_drvdata(dev);
 123         struct devfreq_event_data edata;
 124         int ret;
 125
 126         stat->current_frequency = bus->curr_freq;
 127
 128         ret = exynos_bus_get_event(bus, &edata);
 129         if (ret < 0) {
 130                 dev_err(dev, "failed to get event from devfreq-event devices\n");
 131                 stat->total_time = stat->busy_time = 0;
 132                 goto err;
 133         }
 134
 135         stat->busy_time = (edata.load_count * 100) / bus->ratio;
 136         stat->total_time = edata.total_count;
 137
 138         dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
 139                                                         stat->total_time);
 140
 141 err:
 142         ret = exynos_bus_set_event(bus);
 143         if (ret < 0) {
 144                 dev_err(dev, "failed to set event to devfreq-event devices\n");
 145                 return ret;
 146         }
 147
 148         return ret;
 149 }
 150
 151 static void exynos_bus_exit(struct device *dev)
 152 {
 153         struct exynos_bus *bus = dev_get_drvdata(dev);
 154         int ret;
 155
 156         ret = exynos_bus_disable_edev(bus);
 157         if (ret < 0)
 158                 dev_warn(dev, "failed to disable the devfreq-event devices\n");
 159
 160         platform_device_unregister(bus->icc_pdev);
 161
 162         dev_pm_opp_of_remove_table(dev);
 163         clk_disable_unprepare(bus->clk);
 164         dev_pm_opp_put_regulators(bus->opp_table);
 165         bus->opp_table = NULL;
 166 }
 167
 168 static void exynos_bus_passive_exit(struct device *dev)
 169 {
 170         struct exynos_bus *bus = dev_get_drvdata(dev);
 171
 172         platform_device_unregister(bus->icc_pdev);
 173
 174         dev_pm_opp_of_remove_table(dev);
 175         clk_disable_unprepare(bus->clk);
 176 }
 177
 178 static int exynos_bus_parent_parse_of(struct device_node *np,
 179                                         struct exynos_bus *bus)
 180 {
 181         struct device *dev = bus->dev;
 182         struct opp_table *opp_table;
 183         const char *vdd = "vdd";
 184         int i, ret, count, size;
 185
 186         opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1);
 187         if (IS_ERR(opp_table)) {
 188                 ret = PTR_ERR(opp_table);
 189                 dev_err(dev, "failed to set regulators %d\n", ret);
 190                 return ret;
 191         }
 192
 193         bus->opp_table = opp_table;
 194
 195         /*
 196          * Get the devfreq-event devices to get the current utilization of
 197          * buses. This raw data will be used in devfreq ondemand governor.
 198          */
 199         count = devfreq_event_get_edev_count(dev, "devfreq-events");
 200         if (count < 0) {
 201                 dev_err(dev, "failed to get the count of devfreq-event dev\n");
 202                 ret = count;
 203                 goto err_regulator;
 204         }
 205         bus->edev_count = count;
 206
 207         size = sizeof(*bus->edev) * count;
 208         bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
 209         if (!bus->edev) {
 210                 ret = -ENOMEM;
 211                 goto err_regulator;
 212         }
 213
 214         for (i = 0; i < count; i++) {
 215                 bus->edev[i] = devfreq_event_get_edev_by_phandle(dev,
 216                                                         "devfreq-events", i);
 217                 if (IS_ERR(bus->edev[i])) {
 218                         ret = -EPROBE_DEFER;
 219                         goto err_regulator;
 220                 }
 221         }
 222
 223         /*
 224          * Optionally, Get the saturation ratio according to Exynos SoC
 225          * When measuring the utilization of each AXI bus with devfreq-event
 226          * devices, the measured real cycle might be much lower than the
 227          * total cycle of bus during sampling rate. In result, the devfreq
 228          * simple-ondemand governor might not decide to change the current
 229          * frequency due to too utilization (= real cycle/total cycle).
 230          * So, this property is used to adjust the utilization when calculating
 231          * the busy_time in exynos_bus_get_dev_status().
 232          */
 233         if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
 234                 bus->ratio = DEFAULT_SATURATION_RATIO;
 235
 236         return 0;
 237
 238 err_regulator:
 239         dev_pm_opp_put_regulators(bus->opp_table);
 240         bus->opp_table = NULL;
 241
 242         return ret;
 243 }
 244
 245 static int exynos_bus_parse_of(struct device_node *np,
 246                               struct exynos_bus *bus)
 247 {
 248         struct device *dev = bus->dev;
 249         struct dev_pm_opp *opp;
 250         unsigned long rate;
 251         int ret;
 252
 253         /* Get the clock to provide each bus with source clock */
 254         bus->clk = devm_clk_get(dev, "bus");
 255         if (IS_ERR(bus->clk)) {
 256                 dev_err(dev, "failed to get bus clock\n");
 257                 return PTR_ERR(bus->clk);
 258         }
 259
 260         ret = clk_prepare_enable(bus->clk);
 261         if (ret < 0) {
 262                 dev_err(dev, "failed to get enable clock\n");
 263                 return ret;
 264         }
 265
 266         /* Get the freq and voltage from OPP table to scale the bus freq */
 267         ret = dev_pm_opp_of_add_table(dev);
 268         if (ret < 0) {
 269                 dev_err(dev, "failed to get OPP table\n");
 270                 goto err_clk;
 271         }
 272
 273         rate = clk_get_rate(bus->clk);
 274
 275         opp = devfreq_recommended_opp(dev, &rate, 0);
 276         if (IS_ERR(opp)) {
 277                 dev_err(dev, "failed to find dev_pm_opp\n");
 278                 ret = PTR_ERR(opp);
 279                 goto err_opp;
 280         }
 281         bus->curr_freq = dev_pm_opp_get_freq(opp);
 282         dev_pm_opp_put(opp);
 283
 284         return 0;
 285
 286 err_opp:
 287         dev_pm_opp_of_remove_table(dev);
 288 err_clk:
 289         clk_disable_unprepare(bus->clk);
 290
 291         return ret;
 292 }
 293
 294 static int exynos_bus_profile_init(struct exynos_bus *bus,
 295                                    struct devfreq_dev_profile *profile)
 296 {
 297         struct device *dev = bus->dev;
 298         struct devfreq_simple_ondemand_data *ondemand_data;
 299         int ret;
 300
 301         /* Initialize the struct profile and governor data for parent device */
 302         profile->polling_ms = 50;
 303         profile->target = exynos_bus_target;
 304         profile->get_dev_status = exynos_bus_get_dev_status;
 305         profile->exit = exynos_bus_exit;
 306
 307         ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
 308         if (!ondemand_data)
 309                 return -ENOMEM;
 310
 311         ondemand_data->upthreshold = 40;
 312         ondemand_data->downdifferential = 5;
 313
 314         /* Add devfreq device to monitor and handle the exynos bus */
 315         bus->devfreq = devm_devfreq_add_device(dev, profile,
 316                                                 DEVFREQ_GOV_SIMPLE_ONDEMAND,
 317                                                 ondemand_data);
 318         if (IS_ERR(bus->devfreq)) {
 319                 dev_err(dev, "failed to add devfreq device\n");
 320                 return PTR_ERR(bus->devfreq);
 321         }
 322
 323         /* Register opp_notifier to catch the change of OPP  */
 324         ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
 325         if (ret < 0) {
 326                 dev_err(dev, "failed to register opp notifier\n");
 327                 return ret;
 328         }
 329
 330         /*
 331          * Enable devfreq-event to get raw data which is used to determine
 332          * current bus load.
 333          */
 334         ret = exynos_bus_enable_edev(bus);
 335         if (ret < 0) {
 336                 dev_err(dev, "failed to enable devfreq-event devices\n");
 337                 return ret;
 338         }
 339
 340         ret = exynos_bus_set_event(bus);
 341         if (ret < 0) {
 342                 dev_err(dev, "failed to set event to devfreq-event devices\n");
 343                 goto err_edev;
 344         }
 345
 346         return 0;
 347
 348 err_edev:
 349         if (exynos_bus_disable_edev(bus))
 350                 dev_warn(dev, "failed to disable the devfreq-event devices\n");
 351
 352         return ret;
 353 }
 354
 355 static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
 356                                            struct devfreq_dev_profile *profile)
 357 {
 358         struct device *dev = bus->dev;
 359         struct devfreq_passive_data *passive_data;
 360         struct devfreq *parent_devfreq;
 361
 362         /* Initialize the struct profile and governor data for passive device */
 363         profile->target = exynos_bus_target;
 364         profile->exit = exynos_bus_passive_exit;
 365
 366         /* Get the instance of parent devfreq device */
 367         parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0);
 368         if (IS_ERR(parent_devfreq))
 369                 return -EPROBE_DEFER;
 370
 371         passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
 372         if (!passive_data)
 373                 return -ENOMEM;
 374
 375         passive_data->parent = parent_devfreq;
 376
 377         /* Add devfreq device for exynos bus with passive governor */
 378         bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
 379                                                 passive_data);
 380         if (IS_ERR(bus->devfreq)) {
 381                 dev_err(dev,
 382                         "failed to add devfreq dev with passive governor\n");
 383                 return PTR_ERR(bus->devfreq);
 384         }
 385
 386         return 0;
 387 }
 388
 389 static int exynos_bus_probe(struct platform_device *pdev)
 390 {
 391         struct device *dev = &pdev->dev;
 392         struct device_node *np = dev->of_node, *node;
 393         struct devfreq_dev_profile *profile;
 394         struct exynos_bus *bus;
 395         int ret, max_state;
 396         unsigned long min_freq, max_freq;
 397         bool passive = false;
 398
 399         if (!np) {
 400                 dev_err(dev, "failed to find devicetree node\n");
 401                 return -EINVAL;
 402         }
 403
 404         bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
 405         if (!bus)
 406                 return -ENOMEM;
 407         mutex_init(&bus->lock);
 408         bus->dev = &pdev->dev;
 409         platform_set_drvdata(pdev, bus);
 410
 411         profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
 412         if (!profile)
 413                 return -ENOMEM;
 414
 415         node = of_parse_phandle(dev->of_node, "devfreq", 0);
 416         if (node) {
 417                 of_node_put(node);
 418                 passive = true;
 419         } else {
 420                 ret = exynos_bus_parent_parse_of(np, bus);
 421                 if (ret < 0)
 422                         return ret;
 423         }
 424
 425         /* Parse the device-tree to get the resource information */
 426         ret = exynos_bus_parse_of(np, bus);
 427         if (ret < 0)
 428                 goto err_reg;
 429
 430         if (passive)
 431                 ret = exynos_bus_profile_init_passive(bus, profile);
 432         else
 433                 ret = exynos_bus_profile_init(bus, profile);
 434
 435         if (ret < 0)
 436                 goto err;
 437
 438         /* Create child platform device for the interconnect provider */
 439         if (of_get_property(dev->of_node, "#interconnect-cells", NULL)) {
 440                 bus->icc_pdev = platform_device_register_data(
 441                                                 dev, "exynos-generic-icc",
 442                                                 PLATFORM_DEVID_AUTO, NULL, 0);
 443
 444                 if (IS_ERR(bus->icc_pdev)) {
 445                         ret = PTR_ERR(bus->icc_pdev);
 446                         goto err;
 447                 }
 448         }
 449
 450         max_state = bus->devfreq->profile->max_state;
 451         min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
 452         max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
 453         pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
 454                         dev_name(dev), min_freq, max_freq);
 455
 456         return 0;
 457
 458 err:
 459         dev_pm_opp_of_remove_table(dev);
 460         clk_disable_unprepare(bus->clk);
 461 err_reg:
 462         dev_pm_opp_put_regulators(bus->opp_table);
 463         bus->opp_table = NULL;
 464
 465         return ret;
 466 }
 467
 468 static void exynos_bus_shutdown(struct platform_device *pdev)
 469 {
 470         struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);
 471
 472         devfreq_suspend_device(bus->devfreq);
 473 }
 474
 475 #ifdef CONFIG_PM_SLEEP
 476 static int exynos_bus_resume(struct device *dev)
 477 {
 478         struct exynos_bus *bus = dev_get_drvdata(dev);
 479         int ret;
 480
 481         ret = exynos_bus_enable_edev(bus);
 482         if (ret < 0) {
 483                 dev_err(dev, "failed to enable the devfreq-event devices\n");
 484                 return ret;
 485         }
 486
 487         return 0;
 488 }
 489
 490 static int exynos_bus_suspend(struct device *dev)
 491 {
 492         struct exynos_bus *bus = dev_get_drvdata(dev);
 493         int ret;
 494
 495         ret = exynos_bus_disable_edev(bus);
 496         if (ret < 0) {
 497                 dev_err(dev, "failed to disable the devfreq-event devices\n");
 498                 return ret;
 499         }
 500
 501         return 0;
 502 }
 503 #endif
 504
 505 static const struct dev_pm_ops exynos_bus_pm = {
 506         SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
 507 };
 508
 509 static const struct of_device_id exynos_bus_of_match[] = {
 510         { .compatible = "samsung,exynos-bus", },
 511         { /* sentinel */ },
 512 };
 513 MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
 514
 515 static struct platform_driver exynos_bus_platdrv = {
 516         .probe          = exynos_bus_probe,
 517         .shutdown       = exynos_bus_shutdown,
 518         .driver = {
 519                 .name   = "exynos-bus",
 520                 .pm     = &exynos_bus_pm,
 521                 .of_match_table = of_match_ptr(exynos_bus_of_match),
 522         },
 523 };
 524 module_platform_driver(exynos_bus_platdrv);
 525
 526 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
 527 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
 528 MODULE_LICENSE("GPL v2");