drivers/base/sys.c

   1 /*
   2  * sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
   3  *
   4  * Copyright (c) 2002-3 Patrick Mochel
   5  *               2002-3 Open Source Development Lab
   6  *
   7  * This file is released under the GPLv2
   8  *
   9  * This exports a 'system' bus type.
  10  * By default, a 'sys' bus gets added to the root of the system. There will
  11  * always be core system devices. Devices can use sysdev_register() to
  12  * add themselves as children of the system bus.
  13  */
  14
  15 #include <linux/sysdev.h>
  16 #include <linux/err.h>
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/slab.h>
  21 #include <linux/string.h>
  22 #include <linux/pm.h>
  23 #include <linux/device.h>
  24 #include <linux/mutex.h>
  25
  26 #include "base.h"
  27
  28 extern struct kset devices_subsys;
  29
  30 #define to_sysdev(k) container_of(k, struct sys_device, kobj)
  31 #define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)
  32
  33
  34 static ssize_t
  35 sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
  36 {
  37         struct sys_device * sysdev = to_sysdev(kobj);
  38         struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
  39
  40         if (sysdev_attr->show)
  41                 return sysdev_attr->show(sysdev, buffer);
  42         return -EIO;
  43 }
  44
  45
  46 static ssize_t
  47 sysdev_store(struct kobject * kobj, struct attribute * attr,
  48              const char * buffer, size_t count)
  49 {
  50         struct sys_device * sysdev = to_sysdev(kobj);
  51         struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
  52
  53         if (sysdev_attr->store)
  54                 return sysdev_attr->store(sysdev, buffer, count);
  55         return -EIO;
  56 }
  57
  58 static struct sysfs_ops sysfs_ops = {
  59         .show   = sysdev_show,
  60         .store  = sysdev_store,
  61 };
  62
  63 static struct kobj_type ktype_sysdev = {
  64         .sysfs_ops      = &sysfs_ops,
  65 };
  66
  67
  68 int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)
  69 {
  70         return sysfs_create_file(&s->kobj, &a->attr);
  71 }
  72
  73
  74 void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)
  75 {
  76         sysfs_remove_file(&s->kobj, &a->attr);
  77 }
  78
  79 EXPORT_SYMBOL_GPL(sysdev_create_file);
  80 EXPORT_SYMBOL_GPL(sysdev_remove_file);
  81
  82 #define to_sysdev_class(k) container_of(k, struct sysdev_class, kset.kobj)
  83 #define to_sysdev_class_attr(a) container_of(a, \
  84         struct sysdev_class_attribute, attr)
  85
  86 static ssize_t sysdev_class_show(struct kobject *kobj, struct attribute *attr,
  87                                  char *buffer)
  88 {
  89         struct sysdev_class * class = to_sysdev_class(kobj);
  90         struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);
  91
  92         if (class_attr->show)
  93                 return class_attr->show(class, buffer);
  94         return -EIO;
  95 }
  96
  97 static ssize_t sysdev_class_store(struct kobject *kobj, struct attribute *attr,
  98                                   const char *buffer, size_t count)
  99 {
 100         struct sysdev_class * class = to_sysdev_class(kobj);
 101         struct sysdev_class_attribute * class_attr = to_sysdev_class_attr(attr);
 102
 103         if (class_attr->store)
 104                 return class_attr->store(class, buffer, count);
 105         return -EIO;
 106 }
 107
 108 static struct sysfs_ops sysfs_class_ops = {
 109         .show   = sysdev_class_show,
 110         .store  = sysdev_class_store,
 111 };
 112
 113 static struct kobj_type ktype_sysdev_class = {
 114         .sysfs_ops      = &sysfs_class_ops,
 115 };
 116
 117 int sysdev_class_create_file(struct sysdev_class *c,
 118                              struct sysdev_class_attribute *a)
 119 {
 120         return sysfs_create_file(&c->kset.kobj, &a->attr);
 121 }
 122 EXPORT_SYMBOL_GPL(sysdev_class_create_file);
 123
 124 void sysdev_class_remove_file(struct sysdev_class *c,
 125                               struct sysdev_class_attribute *a)
 126 {
 127         sysfs_remove_file(&c->kset.kobj, &a->attr);
 128 }
 129 EXPORT_SYMBOL_GPL(sysdev_class_remove_file);
 130
 131 /*
 132  * declare system_subsys
 133  */
 134 static decl_subsys(system, &ktype_sysdev_class, NULL);
 135
 136 int sysdev_class_register(struct sysdev_class * cls)
 137 {
 138         pr_debug("Registering sysdev class '%s'\n",
 139                  kobject_name(&cls->kset.kobj));
 140         INIT_LIST_HEAD(&cls->drivers);
 141         cls->kset.kobj.parent = &system_subsys.kobj;
 142         kset_set_kset_s(cls, system_subsys);
 143         return kset_register(&cls->kset);
 144 }
 145
 146 void sysdev_class_unregister(struct sysdev_class * cls)
 147 {
 148         pr_debug("Unregistering sysdev class '%s'\n",
 149                  kobject_name(&cls->kset.kobj));
 150         kset_unregister(&cls->kset);
 151 }
 152
 153 EXPORT_SYMBOL_GPL(sysdev_class_register);
 154 EXPORT_SYMBOL_GPL(sysdev_class_unregister);
 155
 156
 157 static LIST_HEAD(sysdev_drivers);
 158 static DEFINE_MUTEX(sysdev_drivers_lock);
 159
 160 /**
 161  *      sysdev_driver_register - Register auxillary driver
 162  *      @cls:   Device class driver belongs to.
 163  *      @drv:   Driver.
 164  *
 165  *      If @cls is valid, then @drv is inserted into @cls->drivers to be
 166  *      called on each operation on devices of that class. The refcount
 167  *      of @cls is incremented.
 168  *      Otherwise, @drv is inserted into sysdev_drivers, and called for
 169  *      each device.
 170  */
 171
 172 int sysdev_driver_register(struct sysdev_class * cls,
 173                            struct sysdev_driver * drv)
 174 {
 175         mutex_lock(&sysdev_drivers_lock);
 176         if (cls && kset_get(&cls->kset)) {
 177                 list_add_tail(&drv->entry, &cls->drivers);
 178
 179                 /* If devices of this class already exist, tell the driver */
 180                 if (drv->add) {
 181                         struct sys_device *dev;
 182                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 183                                 drv->add(dev);
 184                 }
 185         } else
 186                 list_add_tail(&drv->entry, &sysdev_drivers);
 187         mutex_unlock(&sysdev_drivers_lock);
 188         return 0;
 189 }
 190
 191
 192 /**
 193  *      sysdev_driver_unregister - Remove an auxillary driver.
 194  *      @cls:   Class driver belongs to.
 195  *      @drv:   Driver.
 196  */
 197 void sysdev_driver_unregister(struct sysdev_class * cls,
 198                               struct sysdev_driver * drv)
 199 {
 200         mutex_lock(&sysdev_drivers_lock);
 201         list_del_init(&drv->entry);
 202         if (cls) {
 203                 if (drv->remove) {
 204                         struct sys_device *dev;
 205                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 206                                 drv->remove(dev);
 207                 }
 208                 kset_put(&cls->kset);
 209         }
 210         mutex_unlock(&sysdev_drivers_lock);
 211 }
 212
 213 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 214 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
 215
 216
 217
 218 /**
 219  *      sysdev_register - add a system device to the tree
 220  *      @sysdev:        device in question
 221  *
 222  */
 223 int sysdev_register(struct sys_device * sysdev)
 224 {
 225         int error;
 226         struct sysdev_class * cls = sysdev->cls;
 227
 228         if (!cls)
 229                 return -EINVAL;
 230
 231         /* Make sure the kset is set */
 232         sysdev->kobj.kset = &cls->kset;
 233
 234         /* But make sure we point to the right type for sysfs translation */
 235         sysdev->kobj.ktype = &ktype_sysdev;
 236         error = kobject_set_name(&sysdev->kobj, "%s%d",
 237                          kobject_name(&cls->kset.kobj), sysdev->id);
 238         if (error)
 239                 return error;
 240
 241         pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));
 242
 243         /* Register the object */
 244         error = kobject_register(&sysdev->kobj);
 245
 246         if (!error) {
 247                 struct sysdev_driver * drv;
 248
 249                 mutex_lock(&sysdev_drivers_lock);
 250                 /* Generic notification is implicit, because it's that
 251                  * code that should have called us.
 252                  */
 253
 254                 /* Notify global drivers */
 255                 list_for_each_entry(drv, &sysdev_drivers, entry) {
 256                         if (drv->add)
 257                                 drv->add(sysdev);
 258                 }
 259
 260                 /* Notify class auxillary drivers */
 261                 list_for_each_entry(drv, &cls->drivers, entry) {
 262                         if (drv->add)
 263                                 drv->add(sysdev);
 264                 }
 265                 mutex_unlock(&sysdev_drivers_lock);
 266         }
 267         return error;
 268 }
 269
 270 void sysdev_unregister(struct sys_device * sysdev)
 271 {
 272         struct sysdev_driver * drv;
 273
 274         mutex_lock(&sysdev_drivers_lock);
 275         list_for_each_entry(drv, &sysdev_drivers, entry) {
 276                 if (drv->remove)
 277                         drv->remove(sysdev);
 278         }
 279
 280         list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 281                 if (drv->remove)
 282                         drv->remove(sysdev);
 283         }
 284         mutex_unlock(&sysdev_drivers_lock);
 285
 286         kobject_unregister(&sysdev->kobj);
 287 }
 288
 289
 290
 291 /**
 292  *      sysdev_shutdown - Shut down all system devices.
 293  *
 294  *      Loop over each class of system devices, and the devices in each
 295  *      of those classes. For each device, we call the shutdown method for
 296  *      each driver registered for the device - the globals, the auxillaries,
 297  *      and the class driver.
 298  *
 299  *      Note: The list is iterated in reverse order, so that we shut down
 300  *      child devices before we shut down thier parents. The list ordering
 301  *      is guaranteed by virtue of the fact that child devices are registered
 302  *      after their parents.
 303  */
 304
 305 void sysdev_shutdown(void)
 306 {
 307         struct sysdev_class * cls;
 308
 309         pr_debug("Shutting Down System Devices\n");
 310
 311         mutex_lock(&sysdev_drivers_lock);
 312         list_for_each_entry_reverse(cls, &system_subsys.list,
 313                                     kset.kobj.entry) {
 314                 struct sys_device * sysdev;
 315
 316                 pr_debug("Shutting down type '%s':\n",
 317                          kobject_name(&cls->kset.kobj));
 318
 319                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 320                         struct sysdev_driver * drv;
 321                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 322
 323                         /* Call global drivers first. */
 324                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 325                                 if (drv->shutdown)
 326                                         drv->shutdown(sysdev);
 327                         }
 328
 329                         /* Call auxillary drivers next. */
 330                         list_for_each_entry(drv, &cls->drivers, entry) {
 331                                 if (drv->shutdown)
 332                                         drv->shutdown(sysdev);
 333                         }
 334
 335                         /* Now call the generic one */
 336                         if (cls->shutdown)
 337                                 cls->shutdown(sysdev);
 338                 }
 339         }
 340         mutex_unlock(&sysdev_drivers_lock);
 341 }
 342
 343 static void __sysdev_resume(struct sys_device *dev)
 344 {
 345         struct sysdev_class *cls = dev->cls;
 346         struct sysdev_driver *drv;
 347
 348         /* First, call the class-specific one */
 349         if (cls->resume)
 350                 cls->resume(dev);
 351
 352         /* Call auxillary drivers next. */
 353         list_for_each_entry(drv, &cls->drivers, entry) {
 354                 if (drv->resume)
 355                         drv->resume(dev);
 356         }
 357
 358         /* Call global drivers. */
 359         list_for_each_entry(drv, &sysdev_drivers, entry) {
 360                 if (drv->resume)
 361                         drv->resume(dev);
 362         }
 363 }
 364
 365 /**
 366  *      sysdev_suspend - Suspend all system devices.
 367  *      @state:         Power state to enter.
 368  *
 369  *      We perform an almost identical operation as sys_device_shutdown()
 370  *      above, though calling ->suspend() instead. Interrupts are disabled
 371  *      when this called. Devices are responsible for both saving state and
 372  *      quiescing or powering down the device.
 373  *
 374  *      This is only called by the device PM core, so we let them handle
 375  *      all synchronization.
 376  */
 377
 378 int sysdev_suspend(pm_message_t state)
 379 {
 380         struct sysdev_class * cls;
 381         struct sys_device *sysdev, *err_dev;
 382         struct sysdev_driver *drv, *err_drv;
 383         int ret;
 384
 385         pr_debug("Suspending System Devices\n");
 386
 387         list_for_each_entry_reverse(cls, &system_subsys.list,
 388                                     kset.kobj.entry) {
 389
 390                 pr_debug("Suspending type '%s':\n",
 391                          kobject_name(&cls->kset.kobj));
 392
 393                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 394                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 395
 396                         /* Call global drivers first. */
 397                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 398                                 if (drv->suspend) {
 399                                         ret = drv->suspend(sysdev, state);
 400                                         if (ret)
 401                                                 goto gbl_driver;
 402                                 }
 403                         }
 404
 405                         /* Call auxillary drivers next. */
 406                         list_for_each_entry(drv, &cls->drivers, entry) {
 407                                 if (drv->suspend) {
 408                                         ret = drv->suspend(sysdev, state);
 409                                         if (ret)
 410                                                 goto aux_driver;
 411                                 }
 412                         }
 413
 414                         /* Now call the generic one */
 415                         if (cls->suspend) {
 416                                 ret = cls->suspend(sysdev, state);
 417                                 if (ret)
 418                                         goto cls_driver;
 419                         }
 420                 }
 421         }
 422         return 0;
 423         /* resume current sysdev */
 424 cls_driver:
 425         drv = NULL;
 426         printk(KERN_ERR "Class suspend failed for %s\n",
 427                 kobject_name(&sysdev->kobj));
 428
 429 aux_driver:
 430         if (drv)
 431                 printk(KERN_ERR "Class driver suspend failed for %s\n",
 432                                 kobject_name(&sysdev->kobj));
 433         list_for_each_entry(err_drv, &cls->drivers, entry) {
 434                 if (err_drv == drv)
 435                         break;
 436                 if (err_drv->resume)
 437                         err_drv->resume(sysdev);
 438         }
 439         drv = NULL;
 440
 441 gbl_driver:
 442         if (drv)
 443                 printk(KERN_ERR "sysdev driver suspend failed for %s\n",
 444                                 kobject_name(&sysdev->kobj));
 445         list_for_each_entry(err_drv, &sysdev_drivers, entry) {
 446                 if (err_drv == drv)
 447                         break;
 448                 if (err_drv->resume)
 449                         err_drv->resume(sysdev);
 450         }
 451         /* resume other sysdevs in current class */
 452         list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 453                 if (err_dev == sysdev)
 454                         break;
 455                 pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 456                 __sysdev_resume(err_dev);
 457         }
 458
 459         /* resume other classes */
 460         list_for_each_entry_continue(cls, &system_subsys.list,
 461                                         kset.kobj.entry) {
 462                 list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 463                         pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 464                         __sysdev_resume(err_dev);
 465                 }
 466         }
 467         return ret;
 468 }
 469
 470
 471 /**
 472  *      sysdev_resume - Bring system devices back to life.
 473  *
 474  *      Similar to sys_device_suspend(), but we iterate the list forwards
 475  *      to guarantee that parent devices are resumed before their children.
 476  *
 477  *      Note: Interrupts are disabled when called.
 478  */
 479
 480 int sysdev_resume(void)
 481 {
 482         struct sysdev_class * cls;
 483
 484         pr_debug("Resuming System Devices\n");
 485
 486         list_for_each_entry(cls, &system_subsys.list, kset.kobj.entry) {
 487                 struct sys_device * sysdev;
 488
 489                 pr_debug("Resuming type '%s':\n",
 490                          kobject_name(&cls->kset.kobj));
 491
 492                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 493                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 494
 495                         __sysdev_resume(sysdev);
 496                 }
 497         }
 498         return 0;
 499 }
 500
 501
 502 int __init system_bus_init(void)
 503 {
 504         system_subsys.kobj.parent = &devices_subsys.kobj;
 505         return subsystem_register(&system_subsys);
 506 }
 507
 508 EXPORT_SYMBOL_GPL(sysdev_register);
 509 EXPORT_SYMBOL_GPL(sysdev_unregister);