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         int opp_token;
  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         dev_pm_opp_put_regulators(bus->opp_token);
 164 }
 165
 166 static void exynos_bus_passive_exit(struct device *dev)
 167 {
 168         struct exynos_bus *bus = dev_get_drvdata(dev);
 169
 170         platform_device_unregister(bus->icc_pdev);
 171
 172         dev_pm_opp_of_remove_table(dev);
 173 }
 174
 175 static int exynos_bus_parent_parse_of(struct device_node *np,
 176                                         struct exynos_bus *bus)
 177 {
 178         struct device *dev = bus->dev;
 179         const char *supplies[] = { "vdd", NULL };
 180         int i, ret, count, size;
 181
 182         ret = dev_pm_opp_set_regulators(dev, supplies);
 183         if (ret < 0) {
 184                 dev_err(dev, "failed to set regulators %d\n", ret);
 185                 return ret;
 186         }
 187
 188         bus->opp_token = ret;
 189
 190         /*
 191          * Get the devfreq-event devices to get the current utilization of
 192          * buses. This raw data will be used in devfreq ondemand governor.
 193          */
 194         count = devfreq_event_get_edev_count(dev, "devfreq-events");
 195         if (count < 0) {
 196                 dev_err(dev, "failed to get the count of devfreq-event dev\n");
 197                 ret = count;
 198                 goto err_regulator;
 199         }
 200         bus->edev_count = count;
 201
 202         size = sizeof(*bus->edev) * count;
 203         bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
 204         if (!bus->edev) {
 205                 ret = -ENOMEM;
 206                 goto err_regulator;
 207         }
 208
 209         for (i = 0; i < count; i++) {
 210                 bus->edev[i] = devfreq_event_get_edev_by_phandle(dev,
 211                                                         "devfreq-events", i);
 212                 if (IS_ERR(bus->edev[i])) {
 213                         ret = -EPROBE_DEFER;
 214                         goto err_regulator;
 215                 }
 216         }
 217
 218         /*
 219          * Optionally, Get the saturation ratio according to Exynos SoC
 220          * When measuring the utilization of each AXI bus with devfreq-event
 221          * devices, the measured real cycle might be much lower than the
 222          * total cycle of bus during sampling rate. In result, the devfreq
 223          * simple-ondemand governor might not decide to change the current
 224          * frequency due to too utilization (= real cycle/total cycle).
 225          * So, this property is used to adjust the utilization when calculating
 226          * the busy_time in exynos_bus_get_dev_status().
 227          */
 228         if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
 229                 bus->ratio = DEFAULT_SATURATION_RATIO;
 230
 231         return 0;
 232
 233 err_regulator:
 234         dev_pm_opp_put_regulators(bus->opp_token);
 235
 236         return ret;
 237 }
 238
 239 static int exynos_bus_parse_of(struct device_node *np,
 240                               struct exynos_bus *bus)
 241 {
 242         struct device *dev = bus->dev;
 243         struct dev_pm_opp *opp;
 244         unsigned long rate;
 245         int ret;
 246
 247         /* Get the clock to provide each bus with source clock */
 248         bus->clk = devm_clk_get_enabled(dev, "bus");
 249         if (IS_ERR(bus->clk))
 250                 return dev_err_probe(dev, PTR_ERR(bus->clk),
 251                                 "failed to get bus clock\n");
 252
 253         /* Get the freq and voltage from OPP table to scale the bus freq */
 254         ret = dev_pm_opp_of_add_table(dev);
 255         if (ret < 0) {
 256                 dev_err(dev, "failed to get OPP table\n");
 257                 return ret;
 258         }
 259
 260         rate = clk_get_rate(bus->clk);
 261
 262         opp = devfreq_recommended_opp(dev, &rate, 0);
 263         if (IS_ERR(opp)) {
 264                 dev_err(dev, "failed to find dev_pm_opp\n");
 265                 ret = PTR_ERR(opp);
 266                 goto err_opp;
 267         }
 268         bus->curr_freq = dev_pm_opp_get_freq(opp);
 269         dev_pm_opp_put(opp);
 270
 271         return 0;
 272
 273 err_opp:
 274         dev_pm_opp_of_remove_table(dev);
 275
 276         return ret;
 277 }
 278
 279 static int exynos_bus_profile_init(struct exynos_bus *bus,
 280                                    struct devfreq_dev_profile *profile)
 281 {
 282         struct device *dev = bus->dev;
 283         struct devfreq_simple_ondemand_data *ondemand_data;
 284         int ret;
 285
 286         /* Initialize the struct profile and governor data for parent device */
 287         profile->polling_ms = 50;
 288         profile->target = exynos_bus_target;
 289         profile->get_dev_status = exynos_bus_get_dev_status;
 290         profile->exit = exynos_bus_exit;
 291
 292         ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
 293         if (!ondemand_data)
 294                 return -ENOMEM;
 295
 296         ondemand_data->upthreshold = 40;
 297         ondemand_data->downdifferential = 5;
 298
 299         /* Add devfreq device to monitor and handle the exynos bus */
 300         bus->devfreq = devm_devfreq_add_device(dev, profile,
 301                                                 DEVFREQ_GOV_SIMPLE_ONDEMAND,
 302                                                 ondemand_data);
 303         if (IS_ERR(bus->devfreq)) {
 304                 dev_err(dev, "failed to add devfreq device\n");
 305                 return PTR_ERR(bus->devfreq);
 306         }
 307
 308         /* Register opp_notifier to catch the change of OPP  */
 309         ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
 310         if (ret < 0) {
 311                 dev_err(dev, "failed to register opp notifier\n");
 312                 return ret;
 313         }
 314
 315         /*
 316          * Enable devfreq-event to get raw data which is used to determine
 317          * current bus load.
 318          */
 319         ret = exynos_bus_enable_edev(bus);
 320         if (ret < 0) {
 321                 dev_err(dev, "failed to enable devfreq-event devices\n");
 322                 return ret;
 323         }
 324
 325         ret = exynos_bus_set_event(bus);
 326         if (ret < 0) {
 327                 dev_err(dev, "failed to set event to devfreq-event devices\n");
 328                 goto err_edev;
 329         }
 330
 331         return 0;
 332
 333 err_edev:
 334         if (exynos_bus_disable_edev(bus))
 335                 dev_warn(dev, "failed to disable the devfreq-event devices\n");
 336
 337         return ret;
 338 }
 339
 340 static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
 341                                            struct devfreq_dev_profile *profile)
 342 {
 343         struct device *dev = bus->dev;
 344         struct devfreq_passive_data *passive_data;
 345         struct devfreq *parent_devfreq;
 346
 347         /* Initialize the struct profile and governor data for passive device */
 348         profile->target = exynos_bus_target;
 349         profile->exit = exynos_bus_passive_exit;
 350
 351         /* Get the instance of parent devfreq device */
 352         parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0);
 353         if (IS_ERR(parent_devfreq))
 354                 return -EPROBE_DEFER;
 355
 356         passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
 357         if (!passive_data)
 358                 return -ENOMEM;
 359
 360         passive_data->parent = parent_devfreq;
 361
 362         /* Add devfreq device for exynos bus with passive governor */
 363         bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
 364                                                 passive_data);
 365         if (IS_ERR(bus->devfreq)) {
 366                 dev_err(dev,
 367                         "failed to add devfreq dev with passive governor\n");
 368                 return PTR_ERR(bus->devfreq);
 369         }
 370
 371         return 0;
 372 }
 373
 374 static int exynos_bus_probe(struct platform_device *pdev)
 375 {
 376         struct device *dev = &pdev->dev;
 377         struct device_node *np = dev->of_node, *node;
 378         struct devfreq_dev_profile *profile;
 379         struct exynos_bus *bus;
 380         int ret, max_state;
 381         unsigned long min_freq, max_freq;
 382         bool passive = false;
 383
 384         if (!np) {
 385                 dev_err(dev, "failed to find devicetree node\n");
 386                 return -EINVAL;
 387         }
 388
 389         bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
 390         if (!bus)
 391                 return -ENOMEM;
 392         mutex_init(&bus->lock);
 393         bus->dev = &pdev->dev;
 394         platform_set_drvdata(pdev, bus);
 395
 396         profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
 397         if (!profile)
 398                 return -ENOMEM;
 399
 400         node = of_parse_phandle(dev->of_node, "devfreq", 0);
 401         if (node) {
 402                 of_node_put(node);
 403                 passive = true;
 404         } else {
 405                 ret = exynos_bus_parent_parse_of(np, bus);
 406                 if (ret < 0)
 407                         return ret;
 408         }
 409
 410         /* Parse the device-tree to get the resource information */
 411         ret = exynos_bus_parse_of(np, bus);
 412         if (ret < 0)
 413                 goto err_reg;
 414
 415         if (passive)
 416                 ret = exynos_bus_profile_init_passive(bus, profile);
 417         else
 418                 ret = exynos_bus_profile_init(bus, profile);
 419
 420         if (ret < 0)
 421                 goto err;
 422
 423         /* Create child platform device for the interconnect provider */
 424         if (of_property_present(dev->of_node, "#interconnect-cells")) {
 425                 bus->icc_pdev = platform_device_register_data(
 426                                                 dev, "exynos-generic-icc",
 427                                                 PLATFORM_DEVID_AUTO, NULL, 0);
 428
 429                 if (IS_ERR(bus->icc_pdev)) {
 430                         ret = PTR_ERR(bus->icc_pdev);
 431                         goto err;
 432                 }
 433         }
 434
 435         max_state = bus->devfreq->max_state;
 436         min_freq = (bus->devfreq->freq_table[0] / 1000);
 437         max_freq = (bus->devfreq->freq_table[max_state - 1] / 1000);
 438         pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
 439                         dev_name(dev), min_freq, max_freq);
 440
 441         return 0;
 442
 443 err:
 444         dev_pm_opp_of_remove_table(dev);
 445 err_reg:
 446         dev_pm_opp_put_regulators(bus->opp_token);
 447
 448         return ret;
 449 }
 450
 451 static void exynos_bus_shutdown(struct platform_device *pdev)
 452 {
 453         struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);
 454
 455         devfreq_suspend_device(bus->devfreq);
 456 }
 457
 458 static int exynos_bus_resume(struct device *dev)
 459 {
 460         struct exynos_bus *bus = dev_get_drvdata(dev);
 461         int ret;
 462
 463         ret = exynos_bus_enable_edev(bus);
 464         if (ret < 0) {
 465                 dev_err(dev, "failed to enable the devfreq-event devices\n");
 466                 return ret;
 467         }
 468
 469         return 0;
 470 }
 471
 472 static int exynos_bus_suspend(struct device *dev)
 473 {
 474         struct exynos_bus *bus = dev_get_drvdata(dev);
 475         int ret;
 476
 477         ret = exynos_bus_disable_edev(bus);
 478         if (ret < 0) {
 479                 dev_err(dev, "failed to disable the devfreq-event devices\n");
 480                 return ret;
 481         }
 482
 483         return 0;
 484 }
 485
 486 static DEFINE_SIMPLE_DEV_PM_OPS(exynos_bus_pm,
 487                                 exynos_bus_suspend, exynos_bus_resume);
 488
 489 static const struct of_device_id exynos_bus_of_match[] = {
 490         { .compatible = "samsung,exynos-bus", },
 491         { /* sentinel */ },
 492 };
 493 MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
 494
 495 static struct platform_driver exynos_bus_platdrv = {
 496         .probe          = exynos_bus_probe,
 497         .shutdown       = exynos_bus_shutdown,
 498         .driver = {
 499                 .name   = "exynos-bus",
 500                 .pm     = pm_sleep_ptr(&exynos_bus_pm),
 501                 .of_match_table = exynos_bus_of_match,
 502         },
 503 };
 504 module_platform_driver(exynos_bus_platdrv);
 505
 506 MODULE_SOFTDEP("pre: exynos_ppmu");
 507 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
 508 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
 509 MODULE_LICENSE("GPL v2");