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"); 510