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
  24
  25 extern struct subsystem devices_subsys;
  26
  27 #define to_sysdev(k) container_of(k, struct sys_device, kobj)
  28 #define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)
  29
  30
  31 static ssize_t
  32 sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
  33 {
  34         struct sys_device * sysdev = to_sysdev(kobj);
  35         struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
  36
  37         if (sysdev_attr->show)
  38                 return sysdev_attr->show(sysdev, buffer);
  39         return 0;
  40 }
  41
  42
  43 static ssize_t
  44 sysdev_store(struct kobject * kobj, struct attribute * attr,
  45              const char * buffer, size_t count)
  46 {
  47         struct sys_device * sysdev = to_sysdev(kobj);
  48         struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
  49
  50         if (sysdev_attr->store)
  51                 return sysdev_attr->store(sysdev, buffer, count);
  52         return 0;
  53 }
  54
  55 static struct sysfs_ops sysfs_ops = {
  56         .show   = sysdev_show,
  57         .store  = sysdev_store,
  58 };
  59
  60 static struct kobj_type ktype_sysdev = {
  61         .sysfs_ops      = &sysfs_ops,
  62 };
  63
  64
  65 int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)
  66 {
  67         return sysfs_create_file(&s->kobj, &a->attr);
  68 }
  69
  70
  71 void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)
  72 {
  73         sysfs_remove_file(&s->kobj, &a->attr);
  74 }
  75
  76 EXPORT_SYMBOL_GPL(sysdev_create_file);
  77 EXPORT_SYMBOL_GPL(sysdev_remove_file);
  78
  79 /*
  80  * declare system_subsys
  81  */
  82 static decl_subsys(system, &ktype_sysdev, NULL);
  83
  84 int sysdev_class_register(struct sysdev_class * cls)
  85 {
  86         pr_debug("Registering sysdev class '%s'\n",
  87                  kobject_name(&cls->kset.kobj));
  88         INIT_LIST_HEAD(&cls->drivers);
  89         cls->kset.subsys = &system_subsys;
  90         kset_set_kset_s(cls, system_subsys);
  91         return kset_register(&cls->kset);
  92 }
  93
  94 void sysdev_class_unregister(struct sysdev_class * cls)
  95 {
  96         pr_debug("Unregistering sysdev class '%s'\n",
  97                  kobject_name(&cls->kset.kobj));
  98         kset_unregister(&cls->kset);
  99 }
 100
 101 EXPORT_SYMBOL_GPL(sysdev_class_register);
 102 EXPORT_SYMBOL_GPL(sysdev_class_unregister);
 103
 104
 105 static LIST_HEAD(sysdev_drivers);
 106 static DECLARE_MUTEX(sysdev_drivers_lock);
 107
 108 /**
 109  *      sysdev_driver_register - Register auxillary driver
 110  *      @cls:   Device class driver belongs to.
 111  *      @drv:   Driver.
 112  *
 113  *      If @cls is valid, then @drv is inserted into @cls->drivers to be
 114  *      called on each operation on devices of that class. The refcount
 115  *      of @cls is incremented.
 116  *      Otherwise, @drv is inserted into sysdev_drivers, and called for
 117  *      each device.
 118  */
 119
 120 int sysdev_driver_register(struct sysdev_class * cls,
 121                            struct sysdev_driver * drv)
 122 {
 123         down(&sysdev_drivers_lock);
 124         if (cls && kset_get(&cls->kset)) {
 125                 list_add_tail(&drv->entry, &cls->drivers);
 126
 127                 /* If devices of this class already exist, tell the driver */
 128                 if (drv->add) {
 129                         struct sys_device *dev;
 130                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 131                                 drv->add(dev);
 132                 }
 133         } else
 134                 list_add_tail(&drv->entry, &sysdev_drivers);
 135         up(&sysdev_drivers_lock);
 136         return 0;
 137 }
 138
 139
 140 /**
 141  *      sysdev_driver_unregister - Remove an auxillary driver.
 142  *      @cls:   Class driver belongs to.
 143  *      @drv:   Driver.
 144  */
 145 void sysdev_driver_unregister(struct sysdev_class * cls,
 146                               struct sysdev_driver * drv)
 147 {
 148         down(&sysdev_drivers_lock);
 149         list_del_init(&drv->entry);
 150         if (cls) {
 151                 if (drv->remove) {
 152                         struct sys_device *dev;
 153                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 154                                 drv->remove(dev);
 155                 }
 156                 kset_put(&cls->kset);
 157         }
 158         up(&sysdev_drivers_lock);
 159 }
 160
 161 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 162 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
 163
 164
 165
 166 /**
 167  *      sysdev_register - add a system device to the tree
 168  *      @sysdev:        device in question
 169  *
 170  */
 171 int sysdev_register(struct sys_device * sysdev)
 172 {
 173         int error;
 174         struct sysdev_class * cls = sysdev->cls;
 175
 176         if (!cls)
 177                 return -EINVAL;
 178
 179         /* Make sure the kset is set */
 180         sysdev->kobj.kset = &cls->kset;
 181
 182         /* But make sure we point to the right type for sysfs translation */
 183         sysdev->kobj.ktype = &ktype_sysdev;
 184         error = kobject_set_name(&sysdev->kobj, "%s%d",
 185                          kobject_name(&cls->kset.kobj), sysdev->id);
 186         if (error)
 187                 return error;
 188
 189         pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));
 190
 191         /* Register the object */
 192         error = kobject_register(&sysdev->kobj);
 193
 194         if (!error) {
 195                 struct sysdev_driver * drv;
 196
 197                 down(&sysdev_drivers_lock);
 198                 /* Generic notification is implicit, because it's that
 199                  * code that should have called us.
 200                  */
 201
 202                 /* Notify global drivers */
 203                 list_for_each_entry(drv, &sysdev_drivers, entry) {
 204                         if (drv->add)
 205                                 drv->add(sysdev);
 206                 }
 207
 208                 /* Notify class auxillary drivers */
 209                 list_for_each_entry(drv, &cls->drivers, entry) {
 210                         if (drv->add)
 211                                 drv->add(sysdev);
 212                 }
 213                 up(&sysdev_drivers_lock);
 214         }
 215         return error;
 216 }
 217
 218 void sysdev_unregister(struct sys_device * sysdev)
 219 {
 220         struct sysdev_driver * drv;
 221
 222         down(&sysdev_drivers_lock);
 223         list_for_each_entry(drv, &sysdev_drivers, entry) {
 224                 if (drv->remove)
 225                         drv->remove(sysdev);
 226         }
 227
 228         list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 229                 if (drv->remove)
 230                         drv->remove(sysdev);
 231         }
 232         up(&sysdev_drivers_lock);
 233
 234         kobject_unregister(&sysdev->kobj);
 235 }
 236
 237
 238
 239 /**
 240  *      sysdev_shutdown - Shut down all system devices.
 241  *
 242  *      Loop over each class of system devices, and the devices in each
 243  *      of those classes. For each device, we call the shutdown method for
 244  *      each driver registered for the device - the globals, the auxillaries,
 245  *      and the class driver.
 246  *
 247  *      Note: The list is iterated in reverse order, so that we shut down
 248  *      child devices before we shut down thier parents. The list ordering
 249  *      is guaranteed by virtue of the fact that child devices are registered
 250  *      after their parents.
 251  */
 252
 253 void sysdev_shutdown(void)
 254 {
 255         struct sysdev_class * cls;
 256
 257         pr_debug("Shutting Down System Devices\n");
 258
 259         down(&sysdev_drivers_lock);
 260         list_for_each_entry_reverse(cls, &system_subsys.kset.list,
 261                                     kset.kobj.entry) {
 262                 struct sys_device * sysdev;
 263
 264                 pr_debug("Shutting down type '%s':\n",
 265                          kobject_name(&cls->kset.kobj));
 266
 267                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 268                         struct sysdev_driver * drv;
 269                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 270
 271                         /* Call global drivers first. */
 272                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 273                                 if (drv->shutdown)
 274                                         drv->shutdown(sysdev);
 275                         }
 276
 277                         /* Call auxillary drivers next. */
 278                         list_for_each_entry(drv, &cls->drivers, entry) {
 279                                 if (drv->shutdown)
 280                                         drv->shutdown(sysdev);
 281                         }
 282
 283                         /* Now call the generic one */
 284                         if (cls->shutdown)
 285                                 cls->shutdown(sysdev);
 286                 }
 287         }
 288         up(&sysdev_drivers_lock);
 289 }
 290
 291
 292 /**
 293  *      sysdev_suspend - Suspend all system devices.
 294  *      @state:         Power state to enter.
 295  *
 296  *      We perform an almost identical operation as sys_device_shutdown()
 297  *      above, though calling ->suspend() instead. Interrupts are disabled
 298  *      when this called. Devices are responsible for both saving state and
 299  *      quiescing or powering down the device.
 300  *
 301  *      This is only called by the device PM core, so we let them handle
 302  *      all synchronization.
 303  */
 304
 305 int sysdev_suspend(u32 state)
 306 {
 307         struct sysdev_class * cls;
 308
 309         pr_debug("Suspending System Devices\n");
 310
 311         list_for_each_entry_reverse(cls, &system_subsys.kset.list,
 312                                     kset.kobj.entry) {
 313                 struct sys_device * sysdev;
 314
 315                 pr_debug("Suspending type '%s':\n",
 316                          kobject_name(&cls->kset.kobj));
 317
 318                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 319                         struct sysdev_driver * drv;
 320                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 321
 322                         /* Call global drivers first. */
 323                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 324                                 if (drv->suspend)
 325                                         drv->suspend(sysdev, state);
 326                         }
 327
 328                         /* Call auxillary drivers next. */
 329                         list_for_each_entry(drv, &cls->drivers, entry) {
 330                                 if (drv->suspend)
 331                                         drv->suspend(sysdev, state);
 332                         }
 333
 334                         /* Now call the generic one */
 335                         if (cls->suspend)
 336                                 cls->suspend(sysdev, state);
 337                 }
 338         }
 339         return 0;
 340 }
 341
 342
 343 /**
 344  *      sysdev_resume - Bring system devices back to life.
 345  *
 346  *      Similar to sys_device_suspend(), but we iterate the list forwards
 347  *      to guarantee that parent devices are resumed before their children.
 348  *
 349  *      Note: Interrupts are disabled when called.
 350  */
 351
 352 int sysdev_resume(void)
 353 {
 354         struct sysdev_class * cls;
 355
 356         pr_debug("Resuming System Devices\n");
 357
 358         list_for_each_entry(cls, &system_subsys.kset.list, kset.kobj.entry) {
 359                 struct sys_device * sysdev;
 360
 361                 pr_debug("Resuming type '%s':\n",
 362                          kobject_name(&cls->kset.kobj));
 363
 364                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 365                         struct sysdev_driver * drv;
 366                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 367
 368                         /* First, call the class-specific one */
 369                         if (cls->resume)
 370                                 cls->resume(sysdev);
 371
 372                         /* Call auxillary drivers next. */
 373                         list_for_each_entry(drv, &cls->drivers, entry) {
 374                                 if (drv->resume)
 375                                         drv->resume(sysdev);
 376                         }
 377
 378                         /* Call global drivers. */
 379                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 380                                 if (drv->resume)
 381                                         drv->resume(sysdev);
 382                         }
 383
 384                 }
 385         }
 386         return 0;
 387 }
 388
 389
 390 int __init system_bus_init(void)
 391 {
 392         system_subsys.kset.kobj.parent = &devices_subsys.kset.kobj;
 393         return subsystem_register(&system_subsys);
 394 }
 395
 396 EXPORT_SYMBOL_GPL(sysdev_register);
 397 EXPORT_SYMBOL_GPL(sysdev_unregister);