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_device.h> 19 #include <linux/pm_opp.h> 20 #include <linux/platform_device.h> 21 #include <linux/regulator/consumer.h> 22 #include <linux/slab.h> 23 24 #define DEFAULT_SATURATION_RATIO 40 25 26 struct exynos_bus { 27 struct device *dev; 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 struct opp_table *opp_table; 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 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_probe(struct platform_device *pdev) 291 { 292 struct device *dev = &pdev->dev; 293 struct device_node *np = dev->of_node, *node; 294 struct devfreq_dev_profile *profile; 295 struct devfreq_simple_ondemand_data *ondemand_data; 296 struct devfreq_passive_data *passive_data; 297 struct devfreq *parent_devfreq; 298 struct exynos_bus *bus; 299 int ret, max_state; 300 unsigned long min_freq, max_freq; 301 bool passive = false; 302 303 if (!np) { 304 dev_err(dev, "failed to find devicetree node\n"); 305 return -EINVAL; 306 } 307 308 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL); 309 if (!bus) 310 return -ENOMEM; 311 mutex_init(&bus->lock); 312 bus->dev = &pdev->dev; 313 platform_set_drvdata(pdev, bus); 314 315 profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL); 316 if (!profile) 317 return -ENOMEM; 318 319 node = of_parse_phandle(dev->of_node, "devfreq", 0); 320 if (node) { 321 of_node_put(node); 322 passive = true; 323 } else { 324 ret = exynos_bus_parent_parse_of(np, bus); 325 if (ret < 0) 326 return ret; 327 } 328 329 /* Parse the device-tree to get the resource information */ 330 ret = exynos_bus_parse_of(np, bus); 331 if (ret < 0) 332 goto err_reg; 333 334 if (passive) 335 goto passive; 336 337 /* Initialize the struct profile and governor data for parent device */ 338 profile->polling_ms = 50; 339 profile->target = exynos_bus_target; 340 profile->get_dev_status = exynos_bus_get_dev_status; 341 profile->exit = exynos_bus_exit; 342 343 ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL); 344 if (!ondemand_data) { 345 ret = -ENOMEM; 346 goto err; 347 } 348 ondemand_data->upthreshold = 40; 349 ondemand_data->downdifferential = 5; 350 351 /* Add devfreq device to monitor and handle the exynos bus */ 352 bus->devfreq = devm_devfreq_add_device(dev, profile, 353 DEVFREQ_GOV_SIMPLE_ONDEMAND, 354 ondemand_data); 355 if (IS_ERR(bus->devfreq)) { 356 dev_err(dev, "failed to add devfreq device\n"); 357 ret = PTR_ERR(bus->devfreq); 358 goto err; 359 } 360 361 /* Register opp_notifier to catch the change of OPP */ 362 ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq); 363 if (ret < 0) { 364 dev_err(dev, "failed to register opp notifier\n"); 365 goto err; 366 } 367 368 /* 369 * Enable devfreq-event to get raw data which is used to determine 370 * current bus load. 371 */ 372 ret = exynos_bus_enable_edev(bus); 373 if (ret < 0) { 374 dev_err(dev, "failed to enable devfreq-event devices\n"); 375 goto err; 376 } 377 378 ret = exynos_bus_set_event(bus); 379 if (ret < 0) { 380 dev_err(dev, "failed to set event to devfreq-event devices\n"); 381 goto err; 382 } 383 384 goto out; 385 passive: 386 /* Initialize the struct profile and governor data for passive device */ 387 profile->target = exynos_bus_target; 388 profile->exit = exynos_bus_passive_exit; 389 390 /* Get the instance of parent devfreq device */ 391 parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0); 392 if (IS_ERR(parent_devfreq)) { 393 ret = -EPROBE_DEFER; 394 goto err; 395 } 396 397 passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL); 398 if (!passive_data) { 399 ret = -ENOMEM; 400 goto err; 401 } 402 passive_data->parent = parent_devfreq; 403 404 /* Add devfreq device for exynos bus with passive governor */ 405 bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE, 406 passive_data); 407 if (IS_ERR(bus->devfreq)) { 408 dev_err(dev, 409 "failed to add devfreq dev with passive governor\n"); 410 ret = PTR_ERR(bus->devfreq); 411 goto err; 412 } 413 414 out: 415 max_state = bus->devfreq->profile->max_state; 416 min_freq = (bus->devfreq->profile->freq_table[0] / 1000); 417 max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000); 418 pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n", 419 dev_name(dev), min_freq, max_freq); 420 421 return 0; 422 423 err: 424 dev_pm_opp_of_remove_table(dev); 425 clk_disable_unprepare(bus->clk); 426 err_reg: 427 if (!passive) { 428 dev_pm_opp_put_regulators(bus->opp_table); 429 bus->opp_table = NULL; 430 } 431 432 return ret; 433 } 434 435 static void exynos_bus_shutdown(struct platform_device *pdev) 436 { 437 struct exynos_bus *bus = dev_get_drvdata(&pdev->dev); 438 439 devfreq_suspend_device(bus->devfreq); 440 } 441 442 #ifdef CONFIG_PM_SLEEP 443 static int exynos_bus_resume(struct device *dev) 444 { 445 struct exynos_bus *bus = dev_get_drvdata(dev); 446 int ret; 447 448 ret = exynos_bus_enable_edev(bus); 449 if (ret < 0) { 450 dev_err(dev, "failed to enable the devfreq-event devices\n"); 451 return ret; 452 } 453 454 return 0; 455 } 456 457 static int exynos_bus_suspend(struct device *dev) 458 { 459 struct exynos_bus *bus = dev_get_drvdata(dev); 460 int ret; 461 462 ret = exynos_bus_disable_edev(bus); 463 if (ret < 0) { 464 dev_err(dev, "failed to disable the devfreq-event devices\n"); 465 return ret; 466 } 467 468 return 0; 469 } 470 #endif 471 472 static const struct dev_pm_ops exynos_bus_pm = { 473 SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume) 474 }; 475 476 static const struct of_device_id exynos_bus_of_match[] = { 477 { .compatible = "samsung,exynos-bus", }, 478 { /* sentinel */ }, 479 }; 480 MODULE_DEVICE_TABLE(of, exynos_bus_of_match); 481 482 static struct platform_driver exynos_bus_platdrv = { 483 .probe = exynos_bus_probe, 484 .shutdown = exynos_bus_shutdown, 485 .driver = { 486 .name = "exynos-bus", 487 .pm = &exynos_bus_pm, 488 .of_match_table = of_match_ptr(exynos_bus_of_match), 489 }, 490 }; 491 module_platform_driver(exynos_bus_platdrv); 492 493 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver"); 494 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>"); 495 MODULE_LICENSE("GPL v2"); 496