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         kobject_set_name(&sysdev->kobj,"%s%d",
 184                          kobject_name(&cls->kset.kobj),sysdev->id);
 185         pr_debug("Registering sys device '%s'\n",kobject_name(&sysdev->kobj));
 186
 187         /* Register the object */
 188         error = kobject_register(&sysdev->kobj);
 189
 190         if (!error) {
 191                 struct sysdev_driver * drv;
 192
 193                 down_write(&system_subsys.rwsem);
 194                 /* Generic notification is implicit, because it's that
 195                  * code that should have called us.
 196                  */
 197
 198                 /* Notify global drivers */
 199                 list_for_each_entry(drv,&global_drivers,entry) {
 200                         if (drv->add)
 201                                 drv->add(sysdev);
 202                 }
 203
 204                 /* Notify class auxillary drivers */
 205                 list_for_each_entry(drv,&cls->drivers,entry) {
 206                         if (drv->add)
 207                                 drv->add(sysdev);
 208                 }
 209                 up_write(&system_subsys.rwsem);
 210         }
 211         return error;
 212 }
 213
 214 void sysdev_unregister(struct sys_device * sysdev)
 215 {
 216         struct sysdev_driver * drv;
 217
 218         down_write(&system_subsys.rwsem);
 219         list_for_each_entry(drv,&global_drivers,entry) {
 220                 if (drv->remove)
 221                         drv->remove(sysdev);
 222         }
 223
 224         list_for_each_entry(drv,&sysdev->cls->drivers,entry) {
 225                 if (drv->remove)
 226                         drv->remove(sysdev);
 227         }
 228         up_write(&system_subsys.rwsem);
 229
 230         kobject_unregister(&sysdev->kobj);
 231 }
 232
 233
 234
 235 /**
 236  *      sysdev_shutdown - Shut down all system devices.
 237  *
 238  *      Loop over each class of system devices, and the devices in each
 239  *      of those classes. For each device, we call the shutdown method for
 240  *      each driver registered for the device - the globals, the auxillaries,
 241  *      and the class driver.
 242  *
 243  *      Note: The list is iterated in reverse order, so that we shut down
 244  *      child devices before we shut down thier parents. The list ordering
 245  *      is guaranteed by virtue of the fact that child devices are registered
 246  *      after their parents.
 247  */
 248
 249 void sysdev_shutdown(void)
 250 {
 251         struct sysdev_class * cls;
 252
 253         pr_debug("Shutting Down System Devices\n");
 254
 255         down_write(&system_subsys.rwsem);
 256         list_for_each_entry_reverse(cls,&system_subsys.kset.list,
 257                                     kset.kobj.entry) {
 258                 struct sys_device * sysdev;
 259
 260                 pr_debug("Shutting down type '%s':\n",
 261                          kobject_name(&cls->kset.kobj));
 262
 263                 list_for_each_entry(sysdev,&cls->kset.list,kobj.entry) {
 264                         struct sysdev_driver * drv;
 265                         pr_debug(" %s\n",kobject_name(&sysdev->kobj));
 266
 267                         /* Call global drivers first. */
 268                         list_for_each_entry(drv,&global_drivers,entry) {
 269                                 if (drv->shutdown)
 270                                         drv->shutdown(sysdev);
 271                         }
 272
 273                         /* Call auxillary drivers next. */
 274                         list_for_each_entry(drv,&cls->drivers,entry) {
 275                                 if (drv->shutdown)
 276                                         drv->shutdown(sysdev);
 277                         }
 278
 279                         /* Now call the generic one */
 280                         if (cls->shutdown)
 281                                 cls->shutdown(sysdev);
 282                 }
 283         }
 284         up_write(&system_subsys.rwsem);
 285 }
 286
 287
 288 /**
 289  *      sysdev_suspend - Suspend all system devices.
 290  *      @state:         Power state to enter.
 291  *
 292  *      We perform an almost identical operation as sys_device_shutdown()
 293  *      above, though calling ->suspend() instead. Interrupts are disabled
 294  *      when this called. Devices are responsible for both saving state and
 295  *      quiescing or powering down the device.
 296  *
 297  *      This is only called by the device PM core, so we let them handle
 298  *      all synchronization.
 299  */
 300
 301 int sysdev_suspend(u32 state)
 302 {
 303         struct sysdev_class * cls;
 304
 305         pr_debug("Suspending System Devices\n");
 306
 307         list_for_each_entry_reverse(cls,&system_subsys.kset.list,
 308                                     kset.kobj.entry) {
 309                 struct sys_device * sysdev;
 310
 311                 pr_debug("Suspending type '%s':\n",
 312                          kobject_name(&cls->kset.kobj));
 313
 314                 list_for_each_entry(sysdev,&cls->kset.list,kobj.entry) {
 315                         struct sysdev_driver * drv;
 316                         pr_debug(" %s\n",kobject_name(&sysdev->kobj));
 317
 318                         /* Call global drivers first. */
 319                         list_for_each_entry(drv,&global_drivers,entry) {
 320                                 if (drv->suspend)
 321                                         drv->suspend(sysdev,state);
 322                         }
 323
 324                         /* Call auxillary drivers next. */
 325                         list_for_each_entry(drv,&cls->drivers,entry) {
 326                                 if (drv->suspend)
 327                                         drv->suspend(sysdev,state);
 328                         }
 329
 330                         /* Now call the generic one */
 331                         if (cls->suspend)
 332                                 cls->suspend(sysdev,state);
 333                 }
 334         }
 335         return 0;
 336 }
 337
 338
 339 /**
 340  *      sysdev_resume - Bring system devices back to life.
 341  *
 342  *      Similar to sys_device_suspend(), but we iterate the list forwards
 343  *      to guarantee that parent devices are resumed before their children.
 344  *
 345  *      Note: Interrupts are disabled when called.
 346  */
 347
 348 int sysdev_resume(void)
 349 {
 350         struct sysdev_class * cls;
 351
 352         pr_debug("Resuming System Devices\n");
 353
 354         list_for_each_entry(cls,&system_subsys.kset.list,kset.kobj.entry) {
 355                 struct sys_device * sysdev;
 356
 357                 pr_debug("Resuming type '%s':\n",
 358                          kobject_name(&cls->kset.kobj));
 359
 360                 list_for_each_entry(sysdev,&cls->kset.list,kobj.entry) {
 361                         struct sysdev_driver * drv;
 362                         pr_debug(" %s\n",kobject_name(&sysdev->kobj));
 363
 364                         /* First, call the class-specific one */
 365                         if (cls->resume)
 366                                 cls->resume(sysdev);
 367
 368                         /* Call auxillary drivers next. */
 369                         list_for_each_entry(drv,&cls->drivers,entry) {
 370                                 if (drv->resume)
 371                                         drv->resume(sysdev);
 372                         }
 373
 374                         /* Call global drivers. */
 375                         list_for_each_entry(drv,&global_drivers,entry) {
 376                                 if (drv->resume)
 377                                         drv->resume(sysdev);
 378                         }
 379
 380                 }
 381         }
 382         return 0;
 383 }
 384
 385
 386 int __init system_bus_init(void)
 387 {
 388         system_subsys.kset.kobj.parent = &devices_subsys.kset.kobj;
 389         return subsystem_register(&system_subsys);
 390 }
 391
 392 EXPORT_SYMBOL(sysdev_register);
 393 EXPORT_SYMBOL(sysdev_unregister);