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