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/config.h>
  16 #include <linux/sysdev.h>
  17 #include <linux/err.h>
  18 #include <linux/module.h>
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/slab.h>
  22 #include <linux/string.h>
  23 #include <linux/pm.h>
  24
  25
  26 extern struct subsystem devices_subsys;
  27
  28 #define to_sysdev(k) container_of(k, struct sys_device, kobj)
  29 #define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)
  30
  31
  32 static ssize_t
  33 sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
  34 {
  35         struct sys_device * sysdev = to_sysdev(kobj);
  36         struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
  37
  38         if (sysdev_attr->show)
  39                 return sysdev_attr->show(sysdev, buffer);
  40         return -EIO;
  41 }
  42
  43
  44 static ssize_t
  45 sysdev_store(struct kobject * kobj, struct attribute * attr,
  46              const char * buffer, size_t count)
  47 {
  48         struct sys_device * sysdev = to_sysdev(kobj);
  49         struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
  50
  51         if (sysdev_attr->store)
  52                 return sysdev_attr->store(sysdev, buffer, count);
  53         return -EIO;
  54 }
  55
  56 static struct sysfs_ops sysfs_ops = {
  57         .show   = sysdev_show,
  58         .store  = sysdev_store,
  59 };
  60
  61 static struct kobj_type ktype_sysdev = {
  62         .sysfs_ops      = &sysfs_ops,
  63 };
  64
  65
  66 int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)
  67 {
  68         return sysfs_create_file(&s->kobj, &a->attr);
  69 }
  70
  71
  72 void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)
  73 {
  74         sysfs_remove_file(&s->kobj, &a->attr);
  75 }
  76
  77 EXPORT_SYMBOL_GPL(sysdev_create_file);
  78 EXPORT_SYMBOL_GPL(sysdev_remove_file);
  79
  80 /*
  81  * declare system_subsys
  82  */
  83 static decl_subsys(system, &ktype_sysdev, NULL);
  84
  85 int sysdev_class_register(struct sysdev_class * cls)
  86 {
  87         pr_debug("Registering sysdev class '%s'\n",
  88                  kobject_name(&cls->kset.kobj));
  89         INIT_LIST_HEAD(&cls->drivers);
  90         cls->kset.subsys = &system_subsys;
  91         kset_set_kset_s(cls, system_subsys);
  92         return kset_register(&cls->kset);
  93 }
  94
  95 void sysdev_class_unregister(struct sysdev_class * cls)
  96 {
  97         pr_debug("Unregistering sysdev class '%s'\n",
  98                  kobject_name(&cls->kset.kobj));
  99         kset_unregister(&cls->kset);
 100 }
 101
 102 EXPORT_SYMBOL_GPL(sysdev_class_register);
 103 EXPORT_SYMBOL_GPL(sysdev_class_unregister);
 104
 105
 106 static LIST_HEAD(sysdev_drivers);
 107 static DECLARE_MUTEX(sysdev_drivers_lock);
 108
 109 /**
 110  *      sysdev_driver_register - Register auxillary driver
 111  *      @cls:   Device class driver belongs to.
 112  *      @drv:   Driver.
 113  *
 114  *      If @cls is valid, then @drv is inserted into @cls->drivers to be
 115  *      called on each operation on devices of that class. The refcount
 116  *      of @cls is incremented.
 117  *      Otherwise, @drv is inserted into sysdev_drivers, and called for
 118  *      each device.
 119  */
 120
 121 int sysdev_driver_register(struct sysdev_class * cls,
 122                            struct sysdev_driver * drv)
 123 {
 124         down(&sysdev_drivers_lock);
 125         if (cls && kset_get(&cls->kset)) {
 126                 list_add_tail(&drv->entry, &cls->drivers);
 127
 128                 /* If devices of this class already exist, tell the driver */
 129                 if (drv->add) {
 130                         struct sys_device *dev;
 131                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 132                                 drv->add(dev);
 133                 }
 134         } else
 135                 list_add_tail(&drv->entry, &sysdev_drivers);
 136         up(&sysdev_drivers_lock);
 137         return 0;
 138 }
 139
 140
 141 /**
 142  *      sysdev_driver_unregister - Remove an auxillary driver.
 143  *      @cls:   Class driver belongs to.
 144  *      @drv:   Driver.
 145  */
 146 void sysdev_driver_unregister(struct sysdev_class * cls,
 147                               struct sysdev_driver * drv)
 148 {
 149         down(&sysdev_drivers_lock);
 150         list_del_init(&drv->entry);
 151         if (cls) {
 152                 if (drv->remove) {
 153                         struct sys_device *dev;
 154                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 155                                 drv->remove(dev);
 156                 }
 157                 kset_put(&cls->kset);
 158         }
 159         up(&sysdev_drivers_lock);
 160 }
 161
 162 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 163 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
 164
 165
 166
 167 /**
 168  *      sysdev_register - add a system device to the tree
 169  *      @sysdev:        device in question
 170  *
 171  */
 172 int sysdev_register(struct sys_device * sysdev)
 173 {
 174         int error;
 175         struct sysdev_class * cls = sysdev->cls;
 176
 177         if (!cls)
 178                 return -EINVAL;
 179
 180         /* Make sure the kset is set */
 181         sysdev->kobj.kset = &cls->kset;
 182
 183         /* But make sure we point to the right type for sysfs translation */
 184         sysdev->kobj.ktype = &ktype_sysdev;
 185         error = kobject_set_name(&sysdev->kobj, "%s%d",
 186                          kobject_name(&cls->kset.kobj), sysdev->id);
 187         if (error)
 188                 return error;
 189
 190         pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));
 191
 192         /* Register the object */
 193         error = kobject_register(&sysdev->kobj);
 194
 195         if (!error) {
 196                 struct sysdev_driver * drv;
 197
 198                 down(&sysdev_drivers_lock);
 199                 /* Generic notification is implicit, because it's that
 200                  * code that should have called us.
 201                  */
 202
 203                 /* Notify global drivers */
 204                 list_for_each_entry(drv, &sysdev_drivers, entry) {
 205                         if (drv->add)
 206                                 drv->add(sysdev);
 207                 }
 208
 209                 /* Notify class auxillary drivers */
 210                 list_for_each_entry(drv, &cls->drivers, entry) {
 211                         if (drv->add)
 212                                 drv->add(sysdev);
 213                 }
 214                 up(&sysdev_drivers_lock);
 215         }
 216         return error;
 217 }
 218
 219 void sysdev_unregister(struct sys_device * sysdev)
 220 {
 221         struct sysdev_driver * drv;
 222
 223         down(&sysdev_drivers_lock);
 224         list_for_each_entry(drv, &sysdev_drivers, entry) {
 225                 if (drv->remove)
 226                         drv->remove(sysdev);
 227         }
 228
 229         list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 230                 if (drv->remove)
 231                         drv->remove(sysdev);
 232         }
 233         up(&sysdev_drivers_lock);
 234
 235         kobject_unregister(&sysdev->kobj);
 236 }
 237
 238
 239
 240 /**
 241  *      sysdev_shutdown - Shut down all system devices.
 242  *
 243  *      Loop over each class of system devices, and the devices in each
 244  *      of those classes. For each device, we call the shutdown method for
 245  *      each driver registered for the device - the globals, the auxillaries,
 246  *      and the class driver.
 247  *
 248  *      Note: The list is iterated in reverse order, so that we shut down
 249  *      child devices before we shut down thier parents. The list ordering
 250  *      is guaranteed by virtue of the fact that child devices are registered
 251  *      after their parents.
 252  */
 253
 254 void sysdev_shutdown(void)
 255 {
 256         struct sysdev_class * cls;
 257
 258         pr_debug("Shutting Down System Devices\n");
 259
 260         down(&sysdev_drivers_lock);
 261         list_for_each_entry_reverse(cls, &system_subsys.kset.list,
 262                                     kset.kobj.entry) {
 263                 struct sys_device * sysdev;
 264
 265                 pr_debug("Shutting down type '%s':\n",
 266                          kobject_name(&cls->kset.kobj));
 267
 268                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 269                         struct sysdev_driver * drv;
 270                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 271
 272                         /* Call global drivers first. */
 273                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 274                                 if (drv->shutdown)
 275                                         drv->shutdown(sysdev);
 276                         }
 277
 278                         /* Call auxillary drivers next. */
 279                         list_for_each_entry(drv, &cls->drivers, entry) {
 280                                 if (drv->shutdown)
 281                                         drv->shutdown(sysdev);
 282                         }
 283
 284                         /* Now call the generic one */
 285                         if (cls->shutdown)
 286                                 cls->shutdown(sysdev);
 287                 }
 288         }
 289         up(&sysdev_drivers_lock);
 290 }
 291
 292
 293 /**
 294  *      sysdev_suspend - Suspend all system devices.
 295  *      @state:         Power state to enter.
 296  *
 297  *      We perform an almost identical operation as sys_device_shutdown()
 298  *      above, though calling ->suspend() instead. Interrupts are disabled
 299  *      when this called. Devices are responsible for both saving state and
 300  *      quiescing or powering down the device.
 301  *
 302  *      This is only called by the device PM core, so we let them handle
 303  *      all synchronization.
 304  */
 305
 306 int sysdev_suspend(pm_message_t state)
 307 {
 308         struct sysdev_class * cls;
 309
 310         pr_debug("Suspending System Devices\n");
 311
 312         list_for_each_entry_reverse(cls, &system_subsys.kset.list,
 313                                     kset.kobj.entry) {
 314                 struct sys_device * sysdev;
 315
 316                 pr_debug("Suspending 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->suspend)
 326                                         drv->suspend(sysdev, state);
 327                         }
 328
 329                         /* Call auxillary drivers next. */
 330                         list_for_each_entry(drv, &cls->drivers, entry) {
 331                                 if (drv->suspend)
 332                                         drv->suspend(sysdev, state);
 333                         }
 334
 335                         /* Now call the generic one */
 336                         if (cls->suspend)
 337                                 cls->suspend(sysdev, state);
 338                 }
 339         }
 340         return 0;
 341 }
 342
 343
 344 /**
 345  *      sysdev_resume - Bring system devices back to life.
 346  *
 347  *      Similar to sys_device_suspend(), but we iterate the list forwards
 348  *      to guarantee that parent devices are resumed before their children.
 349  *
 350  *      Note: Interrupts are disabled when called.
 351  */
 352
 353 int sysdev_resume(void)
 354 {
 355         struct sysdev_class * cls;
 356
 357         pr_debug("Resuming System Devices\n");
 358
 359         list_for_each_entry(cls, &system_subsys.kset.list, kset.kobj.entry) {
 360                 struct sys_device * sysdev;
 361
 362                 pr_debug("Resuming type '%s':\n",
 363                          kobject_name(&cls->kset.kobj));
 364
 365                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 366                         struct sysdev_driver * drv;
 367                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 368
 369                         /* First, call the class-specific one */
 370                         if (cls->resume)
 371                                 cls->resume(sysdev);
 372
 373                         /* Call auxillary drivers next. */
 374                         list_for_each_entry(drv, &cls->drivers, entry) {
 375                                 if (drv->resume)
 376                                         drv->resume(sysdev);
 377                         }
 378
 379                         /* Call global drivers. */
 380                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 381                                 if (drv->resume)
 382                                         drv->resume(sysdev);
 383                         }
 384
 385                 }
 386         }
 387         return 0;
 388 }
 389
 390
 391 int __init system_bus_init(void)
 392 {
 393         system_subsys.kset.kobj.parent = &devices_subsys.kset.kobj;
 394         return subsystem_register(&system_subsys);
 395 }
 396
 397 EXPORT_SYMBOL_GPL(sysdev_register);
 398 EXPORT_SYMBOL_GPL(sysdev_unregister);