1 /* 2 * sysfs.c - sysfs support 3 * 4 * (C) 2006-2007 Shaohua Li <shaohua.li@intel.com> 5 * 6 * This code is licenced under the GPL. 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/cpuidle.h> 11 #include <linux/sysfs.h> 12 #include <linux/slab.h> 13 #include <linux/cpu.h> 14 #include <linux/completion.h> 15 #include <linux/capability.h> 16 #include <linux/device.h> 17 #include <linux/kobject.h> 18 19 #include "cpuidle.h" 20 21 static ssize_t show_available_governors(struct device *dev, 22 struct device_attribute *attr, 23 char *buf) 24 { 25 ssize_t i = 0; 26 struct cpuidle_governor *tmp; 27 28 mutex_lock(&cpuidle_lock); 29 list_for_each_entry(tmp, &cpuidle_governors, governor_list) { 30 if (i >= (ssize_t) (PAGE_SIZE - (CPUIDLE_NAME_LEN + 2))) 31 goto out; 32 33 i += scnprintf(&buf[i], CPUIDLE_NAME_LEN + 1, "%s ", tmp->name); 34 } 35 36 out: 37 i+= sprintf(&buf[i], "\n"); 38 mutex_unlock(&cpuidle_lock); 39 return i; 40 } 41 42 static ssize_t show_current_driver(struct device *dev, 43 struct device_attribute *attr, 44 char *buf) 45 { 46 ssize_t ret; 47 struct cpuidle_driver *drv; 48 49 spin_lock(&cpuidle_driver_lock); 50 drv = cpuidle_get_driver(); 51 if (drv) 52 ret = sprintf(buf, "%s\n", drv->name); 53 else 54 ret = sprintf(buf, "none\n"); 55 spin_unlock(&cpuidle_driver_lock); 56 57 return ret; 58 } 59 60 static ssize_t show_current_governor(struct device *dev, 61 struct device_attribute *attr, 62 char *buf) 63 { 64 ssize_t ret; 65 66 mutex_lock(&cpuidle_lock); 67 if (cpuidle_curr_governor) 68 ret = sprintf(buf, "%s\n", cpuidle_curr_governor->name); 69 else 70 ret = sprintf(buf, "none\n"); 71 mutex_unlock(&cpuidle_lock); 72 73 return ret; 74 } 75 76 static ssize_t store_current_governor(struct device *dev, 77 struct device_attribute *attr, 78 const char *buf, size_t count) 79 { 80 char gov_name[CPUIDLE_NAME_LEN + 1]; 81 int ret; 82 struct cpuidle_governor *gov; 83 84 ret = sscanf(buf, "%" __stringify(CPUIDLE_NAME_LEN) "s", gov_name); 85 if (ret != 1) 86 return -EINVAL; 87 88 mutex_lock(&cpuidle_lock); 89 ret = -EINVAL; 90 list_for_each_entry(gov, &cpuidle_governors, governor_list) { 91 if (!strncmp(gov->name, gov_name, CPUIDLE_NAME_LEN)) { 92 ret = cpuidle_switch_governor(gov); 93 break; 94 } 95 } 96 mutex_unlock(&cpuidle_lock); 97 98 return ret ? ret : count; 99 } 100 101 static DEVICE_ATTR(available_governors, 0444, show_available_governors, NULL); 102 static DEVICE_ATTR(current_driver, 0444, show_current_driver, NULL); 103 static DEVICE_ATTR(current_governor, 0644, show_current_governor, 104 store_current_governor); 105 static DEVICE_ATTR(current_governor_ro, 0444, show_current_governor, NULL); 106 107 static struct attribute *cpuidle_attrs[] = { 108 &dev_attr_available_governors.attr, 109 &dev_attr_current_driver.attr, 110 &dev_attr_current_governor.attr, 111 &dev_attr_current_governor_ro.attr, 112 NULL 113 }; 114 115 static struct attribute_group cpuidle_attr_group = { 116 .attrs = cpuidle_attrs, 117 .name = "cpuidle", 118 }; 119 120 /** 121 * cpuidle_add_interface - add CPU global sysfs attributes 122 * @dev: the target device 123 */ 124 int cpuidle_add_interface(struct device *dev) 125 { 126 return sysfs_create_group(&dev->kobj, &cpuidle_attr_group); 127 } 128 129 /** 130 * cpuidle_remove_interface - remove CPU global sysfs attributes 131 * @dev: the target device 132 */ 133 void cpuidle_remove_interface(struct device *dev) 134 { 135 sysfs_remove_group(&dev->kobj, &cpuidle_attr_group); 136 } 137 138 struct cpuidle_attr { 139 struct attribute attr; 140 ssize_t (*show)(struct cpuidle_device *, char *); 141 ssize_t (*store)(struct cpuidle_device *, const char *, size_t count); 142 }; 143 144 #define attr_to_cpuidleattr(a) container_of(a, struct cpuidle_attr, attr) 145 146 struct cpuidle_device_kobj { 147 struct cpuidle_device *dev; 148 struct completion kobj_unregister; 149 struct kobject kobj; 150 }; 151 152 static inline struct cpuidle_device *to_cpuidle_device(struct kobject *kobj) 153 { 154 struct cpuidle_device_kobj *kdev = 155 container_of(kobj, struct cpuidle_device_kobj, kobj); 156 157 return kdev->dev; 158 } 159 160 static ssize_t cpuidle_show(struct kobject *kobj, struct attribute *attr, 161 char *buf) 162 { 163 int ret = -EIO; 164 struct cpuidle_device *dev = to_cpuidle_device(kobj); 165 struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr); 166 167 if (cattr->show) { 168 mutex_lock(&cpuidle_lock); 169 ret = cattr->show(dev, buf); 170 mutex_unlock(&cpuidle_lock); 171 } 172 return ret; 173 } 174 175 static ssize_t cpuidle_store(struct kobject *kobj, struct attribute *attr, 176 const char *buf, size_t count) 177 { 178 int ret = -EIO; 179 struct cpuidle_device *dev = to_cpuidle_device(kobj); 180 struct cpuidle_attr *cattr = attr_to_cpuidleattr(attr); 181 182 if (cattr->store) { 183 mutex_lock(&cpuidle_lock); 184 ret = cattr->store(dev, buf, count); 185 mutex_unlock(&cpuidle_lock); 186 } 187 return ret; 188 } 189 190 static const struct sysfs_ops cpuidle_sysfs_ops = { 191 .show = cpuidle_show, 192 .store = cpuidle_store, 193 }; 194 195 static void cpuidle_sysfs_release(struct kobject *kobj) 196 { 197 struct cpuidle_device_kobj *kdev = 198 container_of(kobj, struct cpuidle_device_kobj, kobj); 199 200 complete(&kdev->kobj_unregister); 201 } 202 203 static struct kobj_type ktype_cpuidle = { 204 .sysfs_ops = &cpuidle_sysfs_ops, 205 .release = cpuidle_sysfs_release, 206 }; 207 208 struct cpuidle_state_attr { 209 struct attribute attr; 210 ssize_t (*show)(struct cpuidle_state *, \ 211 struct cpuidle_state_usage *, char *); 212 ssize_t (*store)(struct cpuidle_state *, \ 213 struct cpuidle_state_usage *, const char *, size_t); 214 }; 215 216 #define define_one_state_ro(_name, show) \ 217 static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0444, show, NULL) 218 219 #define define_one_state_rw(_name, show, store) \ 220 static struct cpuidle_state_attr attr_##_name = __ATTR(_name, 0644, show, store) 221 222 #define define_show_state_function(_name) \ 223 static ssize_t show_state_##_name(struct cpuidle_state *state, \ 224 struct cpuidle_state_usage *state_usage, char *buf) \ 225 { \ 226 return sprintf(buf, "%u\n", state->_name);\ 227 } 228 229 #define define_show_state_ull_function(_name) \ 230 static ssize_t show_state_##_name(struct cpuidle_state *state, \ 231 struct cpuidle_state_usage *state_usage, \ 232 char *buf) \ 233 { \ 234 return sprintf(buf, "%llu\n", state_usage->_name);\ 235 } 236 237 #define define_show_state_str_function(_name) \ 238 static ssize_t show_state_##_name(struct cpuidle_state *state, \ 239 struct cpuidle_state_usage *state_usage, \ 240 char *buf) \ 241 { \ 242 if (state->_name[0] == '\0')\ 243 return sprintf(buf, "<null>\n");\ 244 return sprintf(buf, "%s\n", state->_name);\ 245 } 246 247 #define define_show_state_time_function(_name) \ 248 static ssize_t show_state_##_name(struct cpuidle_state *state, \ 249 struct cpuidle_state_usage *state_usage, \ 250 char *buf) \ 251 { \ 252 return sprintf(buf, "%llu\n", ktime_to_us(state->_name##_ns)); \ 253 } 254 255 define_show_state_time_function(exit_latency) 256 define_show_state_time_function(target_residency) 257 define_show_state_function(power_usage) 258 define_show_state_ull_function(usage) 259 define_show_state_ull_function(rejected) 260 define_show_state_str_function(name) 261 define_show_state_str_function(desc) 262 define_show_state_ull_function(above) 263 define_show_state_ull_function(below) 264 265 static ssize_t show_state_time(struct cpuidle_state *state, 266 struct cpuidle_state_usage *state_usage, 267 char *buf) 268 { 269 return sprintf(buf, "%llu\n", ktime_to_us(state_usage->time_ns)); 270 } 271 272 static ssize_t show_state_disable(struct cpuidle_state *state, 273 struct cpuidle_state_usage *state_usage, 274 char *buf) 275 { 276 return sprintf(buf, "%llu\n", 277 state_usage->disable & CPUIDLE_STATE_DISABLED_BY_USER); 278 } 279 280 static ssize_t store_state_disable(struct cpuidle_state *state, 281 struct cpuidle_state_usage *state_usage, 282 const char *buf, size_t size) 283 { 284 unsigned int value; 285 int err; 286 287 if (!capable(CAP_SYS_ADMIN)) 288 return -EPERM; 289 290 err = kstrtouint(buf, 0, &value); 291 if (err) 292 return err; 293 294 if (value) 295 state_usage->disable |= CPUIDLE_STATE_DISABLED_BY_USER; 296 else 297 state_usage->disable &= ~CPUIDLE_STATE_DISABLED_BY_USER; 298 299 return size; 300 } 301 302 static ssize_t show_state_default_status(struct cpuidle_state *state, 303 struct cpuidle_state_usage *state_usage, 304 char *buf) 305 { 306 return sprintf(buf, "%s\n", 307 state->flags & CPUIDLE_FLAG_OFF ? "disabled" : "enabled"); 308 } 309 310 define_one_state_ro(name, show_state_name); 311 define_one_state_ro(desc, show_state_desc); 312 define_one_state_ro(latency, show_state_exit_latency); 313 define_one_state_ro(residency, show_state_target_residency); 314 define_one_state_ro(power, show_state_power_usage); 315 define_one_state_ro(usage, show_state_usage); 316 define_one_state_ro(rejected, show_state_rejected); 317 define_one_state_ro(time, show_state_time); 318 define_one_state_rw(disable, show_state_disable, store_state_disable); 319 define_one_state_ro(above, show_state_above); 320 define_one_state_ro(below, show_state_below); 321 define_one_state_ro(default_status, show_state_default_status); 322 323 static struct attribute *cpuidle_state_default_attrs[] = { 324 &attr_name.attr, 325 &attr_desc.attr, 326 &attr_latency.attr, 327 &attr_residency.attr, 328 &attr_power.attr, 329 &attr_usage.attr, 330 &attr_rejected.attr, 331 &attr_time.attr, 332 &attr_disable.attr, 333 &attr_above.attr, 334 &attr_below.attr, 335 &attr_default_status.attr, 336 NULL 337 }; 338 ATTRIBUTE_GROUPS(cpuidle_state_default); 339 340 struct cpuidle_state_kobj { 341 struct cpuidle_state *state; 342 struct cpuidle_state_usage *state_usage; 343 struct completion kobj_unregister; 344 struct kobject kobj; 345 struct cpuidle_device *device; 346 }; 347 348 #ifdef CONFIG_SUSPEND 349 #define define_show_state_s2idle_ull_function(_name) \ 350 static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \ 351 struct cpuidle_state_usage *state_usage, \ 352 char *buf) \ 353 { \ 354 return sprintf(buf, "%llu\n", state_usage->s2idle_##_name);\ 355 } 356 357 define_show_state_s2idle_ull_function(usage); 358 define_show_state_s2idle_ull_function(time); 359 360 #define define_one_state_s2idle_ro(_name, show) \ 361 static struct cpuidle_state_attr attr_s2idle_##_name = \ 362 __ATTR(_name, 0444, show, NULL) 363 364 define_one_state_s2idle_ro(usage, show_state_s2idle_usage); 365 define_one_state_s2idle_ro(time, show_state_s2idle_time); 366 367 static struct attribute *cpuidle_state_s2idle_attrs[] = { 368 &attr_s2idle_usage.attr, 369 &attr_s2idle_time.attr, 370 NULL 371 }; 372 373 static const struct attribute_group cpuidle_state_s2idle_group = { 374 .name = "s2idle", 375 .attrs = cpuidle_state_s2idle_attrs, 376 }; 377 378 static void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj) 379 { 380 int ret; 381 382 if (!kobj->state->enter_s2idle) 383 return; 384 385 ret = sysfs_create_group(&kobj->kobj, &cpuidle_state_s2idle_group); 386 if (ret) 387 pr_debug("%s: sysfs attribute group not created\n", __func__); 388 } 389 390 static void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj) 391 { 392 if (kobj->state->enter_s2idle) 393 sysfs_remove_group(&kobj->kobj, &cpuidle_state_s2idle_group); 394 } 395 #else 396 static inline void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { } 397 static inline void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { } 398 #endif /* CONFIG_SUSPEND */ 399 400 #define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj) 401 #define kobj_to_state(k) (kobj_to_state_obj(k)->state) 402 #define kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage) 403 #define kobj_to_device(k) (kobj_to_state_obj(k)->device) 404 #define attr_to_stateattr(a) container_of(a, struct cpuidle_state_attr, attr) 405 406 static ssize_t cpuidle_state_show(struct kobject *kobj, struct attribute *attr, 407 char *buf) 408 { 409 int ret = -EIO; 410 struct cpuidle_state *state = kobj_to_state(kobj); 411 struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj); 412 struct cpuidle_state_attr *cattr = attr_to_stateattr(attr); 413 414 if (cattr->show) 415 ret = cattr->show(state, state_usage, buf); 416 417 return ret; 418 } 419 420 static ssize_t cpuidle_state_store(struct kobject *kobj, struct attribute *attr, 421 const char *buf, size_t size) 422 { 423 int ret = -EIO; 424 struct cpuidle_state *state = kobj_to_state(kobj); 425 struct cpuidle_state_usage *state_usage = kobj_to_state_usage(kobj); 426 struct cpuidle_state_attr *cattr = attr_to_stateattr(attr); 427 struct cpuidle_device *dev = kobj_to_device(kobj); 428 429 if (cattr->store) 430 ret = cattr->store(state, state_usage, buf, size); 431 432 /* reset poll time cache */ 433 dev->poll_limit_ns = 0; 434 435 return ret; 436 } 437 438 static const struct sysfs_ops cpuidle_state_sysfs_ops = { 439 .show = cpuidle_state_show, 440 .store = cpuidle_state_store, 441 }; 442 443 static void cpuidle_state_sysfs_release(struct kobject *kobj) 444 { 445 struct cpuidle_state_kobj *state_obj = kobj_to_state_obj(kobj); 446 447 complete(&state_obj->kobj_unregister); 448 } 449 450 static struct kobj_type ktype_state_cpuidle = { 451 .sysfs_ops = &cpuidle_state_sysfs_ops, 452 .default_groups = cpuidle_state_default_groups, 453 .release = cpuidle_state_sysfs_release, 454 }; 455 456 static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i) 457 { 458 cpuidle_remove_s2idle_attr_group(device->kobjs[i]); 459 kobject_put(&device->kobjs[i]->kobj); 460 wait_for_completion(&device->kobjs[i]->kobj_unregister); 461 kfree(device->kobjs[i]); 462 device->kobjs[i] = NULL; 463 } 464 465 /** 466 * cpuidle_add_state_sysfs - adds cpuidle states sysfs attributes 467 * @device: the target device 468 */ 469 static int cpuidle_add_state_sysfs(struct cpuidle_device *device) 470 { 471 int i, ret = -ENOMEM; 472 struct cpuidle_state_kobj *kobj; 473 struct cpuidle_device_kobj *kdev = device->kobj_dev; 474 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device); 475 476 /* state statistics */ 477 for (i = 0; i < drv->state_count; i++) { 478 kobj = kzalloc(sizeof(struct cpuidle_state_kobj), GFP_KERNEL); 479 if (!kobj) { 480 ret = -ENOMEM; 481 goto error_state; 482 } 483 kobj->state = &drv->states[i]; 484 kobj->state_usage = &device->states_usage[i]; 485 kobj->device = device; 486 init_completion(&kobj->kobj_unregister); 487 488 ret = kobject_init_and_add(&kobj->kobj, &ktype_state_cpuidle, 489 &kdev->kobj, "state%d", i); 490 if (ret) { 491 kobject_put(&kobj->kobj); 492 kfree(kobj); 493 goto error_state; 494 } 495 cpuidle_add_s2idle_attr_group(kobj); 496 kobject_uevent(&kobj->kobj, KOBJ_ADD); 497 device->kobjs[i] = kobj; 498 } 499 500 return 0; 501 502 error_state: 503 for (i = i - 1; i >= 0; i--) 504 cpuidle_free_state_kobj(device, i); 505 return ret; 506 } 507 508 /** 509 * cpuidle_remove_state_sysfs - removes the cpuidle states sysfs attributes 510 * @device: the target device 511 */ 512 static void cpuidle_remove_state_sysfs(struct cpuidle_device *device) 513 { 514 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(device); 515 int i; 516 517 for (i = 0; i < drv->state_count; i++) 518 cpuidle_free_state_kobj(device, i); 519 } 520 521 #ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS 522 #define kobj_to_driver_kobj(k) container_of(k, struct cpuidle_driver_kobj, kobj) 523 #define attr_to_driver_attr(a) container_of(a, struct cpuidle_driver_attr, attr) 524 525 #define define_one_driver_ro(_name, show) \ 526 static struct cpuidle_driver_attr attr_driver_##_name = \ 527 __ATTR(_name, 0444, show, NULL) 528 529 struct cpuidle_driver_kobj { 530 struct cpuidle_driver *drv; 531 struct completion kobj_unregister; 532 struct kobject kobj; 533 }; 534 535 struct cpuidle_driver_attr { 536 struct attribute attr; 537 ssize_t (*show)(struct cpuidle_driver *, char *); 538 ssize_t (*store)(struct cpuidle_driver *, const char *, size_t); 539 }; 540 541 static ssize_t show_driver_name(struct cpuidle_driver *drv, char *buf) 542 { 543 ssize_t ret; 544 545 spin_lock(&cpuidle_driver_lock); 546 ret = sprintf(buf, "%s\n", drv ? drv->name : "none"); 547 spin_unlock(&cpuidle_driver_lock); 548 549 return ret; 550 } 551 552 static void cpuidle_driver_sysfs_release(struct kobject *kobj) 553 { 554 struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj); 555 complete(&driver_kobj->kobj_unregister); 556 } 557 558 static ssize_t cpuidle_driver_show(struct kobject *kobj, struct attribute *attr, 559 char *buf) 560 { 561 int ret = -EIO; 562 struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj); 563 struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr); 564 565 if (dattr->show) 566 ret = dattr->show(driver_kobj->drv, buf); 567 568 return ret; 569 } 570 571 static ssize_t cpuidle_driver_store(struct kobject *kobj, struct attribute *attr, 572 const char *buf, size_t size) 573 { 574 int ret = -EIO; 575 struct cpuidle_driver_kobj *driver_kobj = kobj_to_driver_kobj(kobj); 576 struct cpuidle_driver_attr *dattr = attr_to_driver_attr(attr); 577 578 if (dattr->store) 579 ret = dattr->store(driver_kobj->drv, buf, size); 580 581 return ret; 582 } 583 584 define_one_driver_ro(name, show_driver_name); 585 586 static const struct sysfs_ops cpuidle_driver_sysfs_ops = { 587 .show = cpuidle_driver_show, 588 .store = cpuidle_driver_store, 589 }; 590 591 static struct attribute *cpuidle_driver_default_attrs[] = { 592 &attr_driver_name.attr, 593 NULL 594 }; 595 ATTRIBUTE_GROUPS(cpuidle_driver_default); 596 597 static struct kobj_type ktype_driver_cpuidle = { 598 .sysfs_ops = &cpuidle_driver_sysfs_ops, 599 .default_groups = cpuidle_driver_default_groups, 600 .release = cpuidle_driver_sysfs_release, 601 }; 602 603 /** 604 * cpuidle_add_driver_sysfs - adds the driver name sysfs attribute 605 * @dev: the target device 606 */ 607 static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev) 608 { 609 struct cpuidle_driver_kobj *kdrv; 610 struct cpuidle_device_kobj *kdev = dev->kobj_dev; 611 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); 612 int ret; 613 614 kdrv = kzalloc(sizeof(*kdrv), GFP_KERNEL); 615 if (!kdrv) 616 return -ENOMEM; 617 618 kdrv->drv = drv; 619 init_completion(&kdrv->kobj_unregister); 620 621 ret = kobject_init_and_add(&kdrv->kobj, &ktype_driver_cpuidle, 622 &kdev->kobj, "driver"); 623 if (ret) { 624 kobject_put(&kdrv->kobj); 625 kfree(kdrv); 626 return ret; 627 } 628 629 kobject_uevent(&kdrv->kobj, KOBJ_ADD); 630 dev->kobj_driver = kdrv; 631 632 return ret; 633 } 634 635 /** 636 * cpuidle_remove_driver_sysfs - removes the driver name sysfs attribute 637 * @dev: the target device 638 */ 639 static void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev) 640 { 641 struct cpuidle_driver_kobj *kdrv = dev->kobj_driver; 642 kobject_put(&kdrv->kobj); 643 wait_for_completion(&kdrv->kobj_unregister); 644 kfree(kdrv); 645 } 646 #else 647 static inline int cpuidle_add_driver_sysfs(struct cpuidle_device *dev) 648 { 649 return 0; 650 } 651 652 static inline void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev) 653 { 654 ; 655 } 656 #endif 657 658 /** 659 * cpuidle_add_device_sysfs - adds device specific sysfs attributes 660 * @device: the target device 661 */ 662 int cpuidle_add_device_sysfs(struct cpuidle_device *device) 663 { 664 int ret; 665 666 ret = cpuidle_add_state_sysfs(device); 667 if (ret) 668 return ret; 669 670 ret = cpuidle_add_driver_sysfs(device); 671 if (ret) 672 cpuidle_remove_state_sysfs(device); 673 return ret; 674 } 675 676 /** 677 * cpuidle_remove_device_sysfs : removes device specific sysfs attributes 678 * @device : the target device 679 */ 680 void cpuidle_remove_device_sysfs(struct cpuidle_device *device) 681 { 682 cpuidle_remove_driver_sysfs(device); 683 cpuidle_remove_state_sysfs(device); 684 } 685 686 /** 687 * cpuidle_add_sysfs - creates a sysfs instance for the target device 688 * @dev: the target device 689 */ 690 int cpuidle_add_sysfs(struct cpuidle_device *dev) 691 { 692 struct cpuidle_device_kobj *kdev; 693 struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); 694 int error; 695 696 /* 697 * Return if cpu_device is not setup for this CPU. 698 * 699 * This could happen if the arch did not set up cpu_device 700 * since this CPU is not in cpu_present mask and the 701 * driver did not send a correct CPU mask during registration. 702 * Without this check we would end up passing bogus 703 * value for &cpu_dev->kobj in kobject_init_and_add() 704 */ 705 if (!cpu_dev) 706 return -ENODEV; 707 708 kdev = kzalloc(sizeof(*kdev), GFP_KERNEL); 709 if (!kdev) 710 return -ENOMEM; 711 kdev->dev = dev; 712 713 init_completion(&kdev->kobj_unregister); 714 715 error = kobject_init_and_add(&kdev->kobj, &ktype_cpuidle, &cpu_dev->kobj, 716 "cpuidle"); 717 if (error) { 718 kobject_put(&kdev->kobj); 719 kfree(kdev); 720 return error; 721 } 722 723 dev->kobj_dev = kdev; 724 kobject_uevent(&kdev->kobj, KOBJ_ADD); 725 726 return 0; 727 } 728 729 /** 730 * cpuidle_remove_sysfs - deletes a sysfs instance on the target device 731 * @dev: the target device 732 */ 733 void cpuidle_remove_sysfs(struct cpuidle_device *dev) 734 { 735 struct cpuidle_device_kobj *kdev = dev->kobj_dev; 736 737 kobject_put(&kdev->kobj); 738 wait_for_completion(&kdev->kobj_unregister); 739 kfree(kdev); 740 } 741