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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Generic Exynos Bus frequency driver with DEVFREQ Framework4 *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 using9 * 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 4024 25struct 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 bus43 */44#define exynos_bus_ops_edev(ops) \45static 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}59exynos_bus_ops_edev(enable_edev);60exynos_bus_ops_edev(disable_edev);61exynos_bus_ops_edev(set_event);62 63static 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 governor92 */93static 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 119static 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 141err: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 151static 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 166static 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 175static 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 of192 * 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 SoC220 * When measuring the utilization of each AXI bus with devfreq-event221 * devices, the measured real cycle might be much lower than the222 * total cycle of bus during sampling rate. In result, the devfreq223 * simple-ondemand governor might not decide to change the current224 * frequency due to too utilization (= real cycle/total cycle).225 * So, this property is used to adjust the utilization when calculating226 * 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 233err_regulator:234 dev_pm_opp_put_regulators(bus->opp_token);235 236 return ret;237}238 239static 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 273err_opp:274 dev_pm_opp_of_remove_table(dev);275 276 return ret;277}278 279static 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 determine317 * 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 333err_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 340static 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 374static 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 else418 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 443err:444 dev_pm_opp_of_remove_table(dev);445err_reg:446 dev_pm_opp_put_regulators(bus->opp_token);447 448 return ret;449}450 451static 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 458static 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 472static 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 486static DEFINE_SIMPLE_DEV_PM_OPS(exynos_bus_pm,487 exynos_bus_suspend, exynos_bus_resume);488 489static const struct of_device_id exynos_bus_of_match[] = {490 { .compatible = "samsung,exynos-bus", },491 { /* sentinel */ },492};493MODULE_DEVICE_TABLE(of, exynos_bus_of_match);494 495static 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};504module_platform_driver(exynos_bus_platdrv);505 506MODULE_SOFTDEP("pre: exynos_ppmu");507MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");508MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");509MODULE_LICENSE("GPL v2");510