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