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 exynos_bus *bus) 240 { 241 struct device *dev = bus->dev; 242 struct dev_pm_opp *opp; 243 unsigned long rate; 244 int ret; 245 246 /* Get the clock to provide each bus with source clock */ 247 bus->clk = devm_clk_get_enabled(dev, "bus"); 248 if (IS_ERR(bus->clk)) 249 return dev_err_probe(dev, PTR_ERR(bus->clk), 250 "failed to get bus clock\n"); 251 252 /* Get the freq and voltage from OPP table to scale the bus freq */ 253 ret = dev_pm_opp_of_add_table(dev); 254 if (ret < 0) { 255 dev_err(dev, "failed to get OPP table\n"); 256 return ret; 257 } 258 259 rate = clk_get_rate(bus->clk); 260 261 opp = devfreq_recommended_opp(dev, &rate, 0); 262 if (IS_ERR(opp)) { 263 dev_err(dev, "failed to find dev_pm_opp\n"); 264 ret = PTR_ERR(opp); 265 goto err_opp; 266 } 267 bus->curr_freq = dev_pm_opp_get_freq(opp); 268 dev_pm_opp_put(opp); 269 270 return 0; 271 272 err_opp: 273 dev_pm_opp_of_remove_table(dev); 274 275 return ret; 276 } 277 278 static int exynos_bus_profile_init(struct exynos_bus *bus, 279 struct devfreq_dev_profile *profile) 280 { 281 struct device *dev = bus->dev; 282 struct devfreq_simple_ondemand_data *ondemand_data; 283 int ret; 284 285 /* Initialize the struct profile and governor data for parent device */ 286 profile->polling_ms = 50; 287 profile->target = exynos_bus_target; 288 profile->get_dev_status = exynos_bus_get_dev_status; 289 profile->exit = exynos_bus_exit; 290 291 ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL); 292 if (!ondemand_data) 293 return -ENOMEM; 294 295 ondemand_data->upthreshold = 40; 296 ondemand_data->downdifferential = 5; 297 298 /* Add devfreq device to monitor and handle the exynos bus */ 299 bus->devfreq = devm_devfreq_add_device(dev, profile, 300 DEVFREQ_GOV_SIMPLE_ONDEMAND, 301 ondemand_data); 302 if (IS_ERR(bus->devfreq)) { 303 dev_err(dev, "failed to add devfreq device\n"); 304 return PTR_ERR(bus->devfreq); 305 } 306 307 /* Register opp_notifier to catch the change of OPP */ 308 ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq); 309 if (ret < 0) { 310 dev_err(dev, "failed to register opp notifier\n"); 311 return ret; 312 } 313 314 /* 315 * Enable devfreq-event to get raw data which is used to determine 316 * current bus load. 317 */ 318 ret = exynos_bus_enable_edev(bus); 319 if (ret < 0) { 320 dev_err(dev, "failed to enable devfreq-event devices\n"); 321 return ret; 322 } 323 324 ret = exynos_bus_set_event(bus); 325 if (ret < 0) { 326 dev_err(dev, "failed to set event to devfreq-event devices\n"); 327 goto err_edev; 328 } 329 330 return 0; 331 332 err_edev: 333 if (exynos_bus_disable_edev(bus)) 334 dev_warn(dev, "failed to disable the devfreq-event devices\n"); 335 336 return ret; 337 } 338 339 static int exynos_bus_profile_init_passive(struct exynos_bus *bus, 340 struct devfreq_dev_profile *profile) 341 { 342 struct device *dev = bus->dev; 343 struct devfreq_passive_data *passive_data; 344 struct devfreq *parent_devfreq; 345 346 /* Initialize the struct profile and governor data for passive device */ 347 profile->target = exynos_bus_target; 348 profile->exit = exynos_bus_passive_exit; 349 350 /* Get the instance of parent devfreq device */ 351 parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0); 352 if (IS_ERR(parent_devfreq)) 353 return -EPROBE_DEFER; 354 355 passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL); 356 if (!passive_data) 357 return -ENOMEM; 358 359 passive_data->parent = parent_devfreq; 360 361 /* Add devfreq device for exynos bus with passive governor */ 362 bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE, 363 passive_data); 364 if (IS_ERR(bus->devfreq)) { 365 dev_err(dev, 366 "failed to add devfreq dev with passive governor\n"); 367 return PTR_ERR(bus->devfreq); 368 } 369 370 return 0; 371 } 372 373 static int exynos_bus_probe(struct platform_device *pdev) 374 { 375 struct device *dev = &pdev->dev; 376 struct device_node *np = dev->of_node, *node; 377 struct devfreq_dev_profile *profile; 378 struct exynos_bus *bus; 379 int ret, max_state; 380 unsigned long min_freq, max_freq; 381 bool passive = false; 382 383 if (!np) { 384 dev_err(dev, "failed to find devicetree node\n"); 385 return -EINVAL; 386 } 387 388 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL); 389 if (!bus) 390 return -ENOMEM; 391 mutex_init(&bus->lock); 392 bus->dev = &pdev->dev; 393 platform_set_drvdata(pdev, bus); 394 395 profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL); 396 if (!profile) 397 return -ENOMEM; 398 399 node = of_parse_phandle(dev->of_node, "devfreq", 0); 400 if (node) { 401 of_node_put(node); 402 passive = true; 403 } else { 404 ret = exynos_bus_parent_parse_of(np, bus); 405 if (ret < 0) 406 return ret; 407 } 408 409 /* Parse the device-tree to get the resource information */ 410 ret = exynos_bus_parse_of(bus); 411 if (ret < 0) 412 goto err_reg; 413 414 if (passive) 415 ret = exynos_bus_profile_init_passive(bus, profile); 416 else 417 ret = exynos_bus_profile_init(bus, profile); 418 419 if (ret < 0) 420 goto err; 421 422 /* Create child platform device for the interconnect provider */ 423 if (of_property_present(dev->of_node, "#interconnect-cells")) { 424 bus->icc_pdev = platform_device_register_data( 425 dev, "exynos-generic-icc", 426 PLATFORM_DEVID_AUTO, NULL, 0); 427 428 if (IS_ERR(bus->icc_pdev)) { 429 ret = PTR_ERR(bus->icc_pdev); 430 goto err; 431 } 432 } 433 434 max_state = bus->devfreq->max_state; 435 min_freq = (bus->devfreq->freq_table[0] / 1000); 436 max_freq = (bus->devfreq->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 err_reg: 445 dev_pm_opp_put_regulators(bus->opp_token); 446 447 return ret; 448 } 449 450 static void exynos_bus_shutdown(struct platform_device *pdev) 451 { 452 struct exynos_bus *bus = dev_get_drvdata(&pdev->dev); 453 454 devfreq_suspend_device(bus->devfreq); 455 } 456 457 static int exynos_bus_resume(struct device *dev) 458 { 459 struct exynos_bus *bus = dev_get_drvdata(dev); 460 int ret; 461 462 ret = exynos_bus_enable_edev(bus); 463 if (ret < 0) { 464 dev_err(dev, "failed to enable the devfreq-event devices\n"); 465 return ret; 466 } 467 468 return 0; 469 } 470 471 static int exynos_bus_suspend(struct device *dev) 472 { 473 struct exynos_bus *bus = dev_get_drvdata(dev); 474 int ret; 475 476 ret = exynos_bus_disable_edev(bus); 477 if (ret < 0) { 478 dev_err(dev, "failed to disable the devfreq-event devices\n"); 479 return ret; 480 } 481 482 return 0; 483 } 484 485 static DEFINE_SIMPLE_DEV_PM_OPS(exynos_bus_pm, 486 exynos_bus_suspend, exynos_bus_resume); 487 488 static const struct of_device_id exynos_bus_of_match[] = { 489 { .compatible = "samsung,exynos-bus", }, 490 { /* sentinel */ }, 491 }; 492 MODULE_DEVICE_TABLE(of, exynos_bus_of_match); 493 494 static struct platform_driver exynos_bus_platdrv = { 495 .probe = exynos_bus_probe, 496 .shutdown = exynos_bus_shutdown, 497 .driver = { 498 .name = "exynos-bus", 499 .pm = pm_sleep_ptr(&exynos_bus_pm), 500 .of_match_table = exynos_bus_of_match, 501 }, 502 }; 503 module_platform_driver(exynos_bus_platdrv); 504 505 MODULE_SOFTDEP("pre: exynos_ppmu"); 506 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver"); 507 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>"); 508 MODULE_LICENSE("GPL v2"); 509