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 clk_disable_unprepare(bus->clk); 164 dev_pm_opp_put_regulators(bus->opp_token); 165 } 166 167 static void exynos_bus_passive_exit(struct device *dev) 168 { 169 struct exynos_bus *bus = dev_get_drvdata(dev); 170 171 platform_device_unregister(bus->icc_pdev); 172 173 dev_pm_opp_of_remove_table(dev); 174 clk_disable_unprepare(bus->clk); 175 } 176 177 static int exynos_bus_parent_parse_of(struct device_node *np, 178 struct exynos_bus *bus) 179 { 180 struct device *dev = bus->dev; 181 const char *supplies[] = { "vdd", NULL }; 182 int i, ret, count, size; 183 184 ret = dev_pm_opp_set_regulators(dev, supplies); 185 if (ret < 0) { 186 dev_err(dev, "failed to set regulators %d\n", ret); 187 return ret; 188 } 189 190 bus->opp_token = ret; 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_token); 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, "devfreq", 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 /* Create child platform device for the interconnect provider */ 435 if (of_property_present(dev->of_node, "#interconnect-cells")) { 436 bus->icc_pdev = platform_device_register_data( 437 dev, "exynos-generic-icc", 438 PLATFORM_DEVID_AUTO, NULL, 0); 439 440 if (IS_ERR(bus->icc_pdev)) { 441 ret = PTR_ERR(bus->icc_pdev); 442 goto err; 443 } 444 } 445 446 max_state = bus->devfreq->max_state; 447 min_freq = (bus->devfreq->freq_table[0] / 1000); 448 max_freq = (bus->devfreq->freq_table[max_state - 1] / 1000); 449 pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n", 450 dev_name(dev), min_freq, max_freq); 451 452 return 0; 453 454 err: 455 dev_pm_opp_of_remove_table(dev); 456 clk_disable_unprepare(bus->clk); 457 err_reg: 458 dev_pm_opp_put_regulators(bus->opp_token); 459 460 return ret; 461 } 462 463 static void exynos_bus_shutdown(struct platform_device *pdev) 464 { 465 struct exynos_bus *bus = dev_get_drvdata(&pdev->dev); 466 467 devfreq_suspend_device(bus->devfreq); 468 } 469 470 #ifdef CONFIG_PM_SLEEP 471 static int exynos_bus_resume(struct device *dev) 472 { 473 struct exynos_bus *bus = dev_get_drvdata(dev); 474 int ret; 475 476 ret = exynos_bus_enable_edev(bus); 477 if (ret < 0) { 478 dev_err(dev, "failed to enable the devfreq-event devices\n"); 479 return ret; 480 } 481 482 return 0; 483 } 484 485 static int exynos_bus_suspend(struct device *dev) 486 { 487 struct exynos_bus *bus = dev_get_drvdata(dev); 488 int ret; 489 490 ret = exynos_bus_disable_edev(bus); 491 if (ret < 0) { 492 dev_err(dev, "failed to disable the devfreq-event devices\n"); 493 return ret; 494 } 495 496 return 0; 497 } 498 #endif 499 500 static const struct dev_pm_ops exynos_bus_pm = { 501 SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume) 502 }; 503 504 static const struct of_device_id exynos_bus_of_match[] = { 505 { .compatible = "samsung,exynos-bus", }, 506 { /* sentinel */ }, 507 }; 508 MODULE_DEVICE_TABLE(of, exynos_bus_of_match); 509 510 static struct platform_driver exynos_bus_platdrv = { 511 .probe = exynos_bus_probe, 512 .shutdown = exynos_bus_shutdown, 513 .driver = { 514 .name = "exynos-bus", 515 .pm = &exynos_bus_pm, 516 .of_match_table = exynos_bus_of_match, 517 }, 518 }; 519 module_platform_driver(exynos_bus_platdrv); 520 521 MODULE_SOFTDEP("pre: exynos_ppmu"); 522 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver"); 523 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>"); 524 MODULE_LICENSE("GPL v2"); 525