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); 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, i); 213 if (IS_ERR(bus->edev[i])) { 214 ret = -EPROBE_DEFER; 215 goto err_regulator; 216 } 217 } 218 219 /* 220 * Optionally, Get the saturation ratio according to Exynos SoC 221 * When measuring the utilization of each AXI bus with devfreq-event 222 * devices, the measured real cycle might be much lower than the 223 * total cycle of bus during sampling rate. In result, the devfreq 224 * simple-ondemand governor might not decide to change the current 225 * frequency due to too utilization (= real cycle/total cycle). 226 * So, this property is used to adjust the utilization when calculating 227 * the busy_time in exynos_bus_get_dev_status(). 228 */ 229 if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio)) 230 bus->ratio = DEFAULT_SATURATION_RATIO; 231 232 return 0; 233 234 err_regulator: 235 dev_pm_opp_put_regulators(bus->opp_table); 236 bus->opp_table = NULL; 237 238 return ret; 239 } 240 241 static int exynos_bus_parse_of(struct device_node *np, 242 struct exynos_bus *bus) 243 { 244 struct device *dev = bus->dev; 245 struct dev_pm_opp *opp; 246 unsigned long rate; 247 int ret; 248 249 /* Get the clock to provide each bus with source clock */ 250 bus->clk = devm_clk_get(dev, "bus"); 251 if (IS_ERR(bus->clk)) { 252 dev_err(dev, "failed to get bus clock\n"); 253 return PTR_ERR(bus->clk); 254 } 255 256 ret = clk_prepare_enable(bus->clk); 257 if (ret < 0) { 258 dev_err(dev, "failed to get enable clock\n"); 259 return ret; 260 } 261 262 /* Get the freq and voltage from OPP table to scale the bus freq */ 263 ret = dev_pm_opp_of_add_table(dev); 264 if (ret < 0) { 265 dev_err(dev, "failed to get OPP table\n"); 266 goto err_clk; 267 } 268 269 rate = clk_get_rate(bus->clk); 270 271 opp = devfreq_recommended_opp(dev, &rate, 0); 272 if (IS_ERR(opp)) { 273 dev_err(dev, "failed to find dev_pm_opp\n"); 274 ret = PTR_ERR(opp); 275 goto err_opp; 276 } 277 bus->curr_freq = dev_pm_opp_get_freq(opp); 278 dev_pm_opp_put(opp); 279 280 return 0; 281 282 err_opp: 283 dev_pm_opp_of_remove_table(dev); 284 err_clk: 285 clk_disable_unprepare(bus->clk); 286 287 return ret; 288 } 289 290 static int exynos_bus_profile_init(struct exynos_bus *bus, 291 struct devfreq_dev_profile *profile) 292 { 293 struct device *dev = bus->dev; 294 struct devfreq_simple_ondemand_data *ondemand_data; 295 int ret; 296 297 /* Initialize the struct profile and governor data for parent device */ 298 profile->polling_ms = 50; 299 profile->target = exynos_bus_target; 300 profile->get_dev_status = exynos_bus_get_dev_status; 301 profile->exit = exynos_bus_exit; 302 303 ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL); 304 if (!ondemand_data) 305 return -ENOMEM; 306 307 ondemand_data->upthreshold = 40; 308 ondemand_data->downdifferential = 5; 309 310 /* Add devfreq device to monitor and handle the exynos bus */ 311 bus->devfreq = devm_devfreq_add_device(dev, profile, 312 DEVFREQ_GOV_SIMPLE_ONDEMAND, 313 ondemand_data); 314 if (IS_ERR(bus->devfreq)) { 315 dev_err(dev, "failed to add devfreq device\n"); 316 return PTR_ERR(bus->devfreq); 317 } 318 319 /* Register opp_notifier to catch the change of OPP */ 320 ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq); 321 if (ret < 0) { 322 dev_err(dev, "failed to register opp notifier\n"); 323 return ret; 324 } 325 326 /* 327 * Enable devfreq-event to get raw data which is used to determine 328 * current bus load. 329 */ 330 ret = exynos_bus_enable_edev(bus); 331 if (ret < 0) { 332 dev_err(dev, "failed to enable devfreq-event devices\n"); 333 return ret; 334 } 335 336 ret = exynos_bus_set_event(bus); 337 if (ret < 0) { 338 dev_err(dev, "failed to set event to devfreq-event devices\n"); 339 goto err_edev; 340 } 341 342 return 0; 343 344 err_edev: 345 if (exynos_bus_disable_edev(bus)) 346 dev_warn(dev, "failed to disable the devfreq-event devices\n"); 347 348 return ret; 349 } 350 351 static int exynos_bus_profile_init_passive(struct exynos_bus *bus, 352 struct devfreq_dev_profile *profile) 353 { 354 struct device *dev = bus->dev; 355 struct devfreq_passive_data *passive_data; 356 struct devfreq *parent_devfreq; 357 358 /* Initialize the struct profile and governor data for passive device */ 359 profile->target = exynos_bus_target; 360 profile->exit = exynos_bus_passive_exit; 361 362 /* Get the instance of parent devfreq device */ 363 parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0); 364 if (IS_ERR(parent_devfreq)) 365 return -EPROBE_DEFER; 366 367 passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL); 368 if (!passive_data) 369 return -ENOMEM; 370 371 passive_data->parent = parent_devfreq; 372 373 /* Add devfreq device for exynos bus with passive governor */ 374 bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE, 375 passive_data); 376 if (IS_ERR(bus->devfreq)) { 377 dev_err(dev, 378 "failed to add devfreq dev with passive governor\n"); 379 return PTR_ERR(bus->devfreq); 380 } 381 382 return 0; 383 } 384 385 static int exynos_bus_probe(struct platform_device *pdev) 386 { 387 struct device *dev = &pdev->dev; 388 struct device_node *np = dev->of_node, *node; 389 struct devfreq_dev_profile *profile; 390 struct exynos_bus *bus; 391 int ret, max_state; 392 unsigned long min_freq, max_freq; 393 bool passive = false; 394 395 if (!np) { 396 dev_err(dev, "failed to find devicetree node\n"); 397 return -EINVAL; 398 } 399 400 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL); 401 if (!bus) 402 return -ENOMEM; 403 mutex_init(&bus->lock); 404 bus->dev = &pdev->dev; 405 platform_set_drvdata(pdev, bus); 406 407 profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL); 408 if (!profile) 409 return -ENOMEM; 410 411 node = of_parse_phandle(dev->of_node, "devfreq", 0); 412 if (node) { 413 of_node_put(node); 414 passive = true; 415 } else { 416 ret = exynos_bus_parent_parse_of(np, bus); 417 if (ret < 0) 418 return ret; 419 } 420 421 /* Parse the device-tree to get the resource information */ 422 ret = exynos_bus_parse_of(np, bus); 423 if (ret < 0) 424 goto err_reg; 425 426 if (passive) 427 ret = exynos_bus_profile_init_passive(bus, profile); 428 else 429 ret = exynos_bus_profile_init(bus, profile); 430 431 if (ret < 0) 432 goto err; 433 434 max_state = bus->devfreq->profile->max_state; 435 min_freq = (bus->devfreq->profile->freq_table[0] / 1000); 436 max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000); 437 pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n", 438 dev_name(dev), min_freq, max_freq); 439 440 return 0; 441 442 err: 443 dev_pm_opp_of_remove_table(dev); 444 clk_disable_unprepare(bus->clk); 445 err_reg: 446 if (!passive) { 447 dev_pm_opp_put_regulators(bus->opp_table); 448 bus->opp_table = NULL; 449 } 450 451 return ret; 452 } 453 454 static void exynos_bus_shutdown(struct platform_device *pdev) 455 { 456 struct exynos_bus *bus = dev_get_drvdata(&pdev->dev); 457 458 devfreq_suspend_device(bus->devfreq); 459 } 460 461 #ifdef CONFIG_PM_SLEEP 462 static int exynos_bus_resume(struct device *dev) 463 { 464 struct exynos_bus *bus = dev_get_drvdata(dev); 465 int ret; 466 467 ret = exynos_bus_enable_edev(bus); 468 if (ret < 0) { 469 dev_err(dev, "failed to enable the devfreq-event devices\n"); 470 return ret; 471 } 472 473 return 0; 474 } 475 476 static int exynos_bus_suspend(struct device *dev) 477 { 478 struct exynos_bus *bus = dev_get_drvdata(dev); 479 int ret; 480 481 ret = exynos_bus_disable_edev(bus); 482 if (ret < 0) { 483 dev_err(dev, "failed to disable the devfreq-event devices\n"); 484 return ret; 485 } 486 487 return 0; 488 } 489 #endif 490 491 static const struct dev_pm_ops exynos_bus_pm = { 492 SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume) 493 }; 494 495 static const struct of_device_id exynos_bus_of_match[] = { 496 { .compatible = "samsung,exynos-bus", }, 497 { /* sentinel */ }, 498 }; 499 MODULE_DEVICE_TABLE(of, exynos_bus_of_match); 500 501 static struct platform_driver exynos_bus_platdrv = { 502 .probe = exynos_bus_probe, 503 .shutdown = exynos_bus_shutdown, 504 .driver = { 505 .name = "exynos-bus", 506 .pm = &exynos_bus_pm, 507 .of_match_table = of_match_ptr(exynos_bus_of_match), 508 }, 509 }; 510 module_platform_driver(exynos_bus_platdrv); 511 512 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver"); 513 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>"); 514 MODULE_LICENSE("GPL v2"); 515