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 #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 #define to_sysdev_class(k) container_of(k, struct sysdev_class, kset.kobj)
  81 #define to_sysdev_class_attr(a) container_of(a, \
  82         struct sysdev_class_attribute, attr)
  83
  84 static ssize_t sysdev_class_show(struct kobject *kobj, struct attribute *attr,
  85                                  char *buffer)
  86 {
  87         struct sysdev_class * class = to_sysdev_class(kobj);
  88         struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);
  89
  90         if (class_attr->show)
  91                 return class_attr->show(class, buffer);
  92         return -EIO;
  93 }
  94
  95 static ssize_t sysdev_class_store(struct kobject *kobj, struct attribute *attr,
  96                                   const char *buffer, size_t count)
  97 {
  98         struct sysdev_class * class = to_sysdev_class(kobj);
  99         struct sysdev_class_attribute * class_attr = to_sysdev_class_attr(attr);
 100
 101         if (class_attr->store)
 102                 return class_attr->store(class, buffer, count);
 103         return -EIO;
 104 }
 105
 106 static struct sysfs_ops sysfs_class_ops = {
 107         .show   = sysdev_class_show,
 108         .store  = sysdev_class_store,
 109 };
 110
 111 static struct kobj_type ktype_sysdev_class = {
 112         .sysfs_ops      = &sysfs_class_ops,
 113 };
 114
 115 int sysdev_class_create_file(struct sysdev_class *c,
 116                              struct sysdev_class_attribute *a)
 117 {
 118         return sysfs_create_file(&c->kset.kobj, &a->attr);
 119 }
 120 EXPORT_SYMBOL_GPL(sysdev_class_create_file);
 121
 122 void sysdev_class_remove_file(struct sysdev_class *c,
 123                               struct sysdev_class_attribute *a)
 124 {
 125         sysfs_remove_file(&c->kset.kobj, &a->attr);
 126 }
 127 EXPORT_SYMBOL_GPL(sysdev_class_remove_file);
 128
 129 static struct kset *system_kset;
 130
 131 int sysdev_class_register(struct sysdev_class * cls)
 132 {
 133         pr_debug("Registering sysdev class '%s'\n",
 134                  kobject_name(&cls->kset.kobj));
 135         INIT_LIST_HEAD(&cls->drivers);
 136         cls->kset.kobj.parent = &system_kset->kobj;
 137         cls->kset.kobj.ktype = &ktype_sysdev_class;
 138         cls->kset.kobj.kset = system_kset;
 139         kobject_set_name(&cls->kset.kobj, cls->name);
 140         return kset_register(&cls->kset);
 141 }
 142
 143 void sysdev_class_unregister(struct sysdev_class * cls)
 144 {
 145         pr_debug("Unregistering sysdev class '%s'\n",
 146                  kobject_name(&cls->kset.kobj));
 147         kset_unregister(&cls->kset);
 148 }
 149
 150 EXPORT_SYMBOL_GPL(sysdev_class_register);
 151 EXPORT_SYMBOL_GPL(sysdev_class_unregister);
 152
 153 static DEFINE_MUTEX(sysdev_drivers_lock);
 154
 155 /**
 156  *      sysdev_driver_register - Register auxillary driver
 157  *      @cls:   Device class driver belongs to.
 158  *      @drv:   Driver.
 159  *
 160  *      @drv is inserted into @cls->drivers to be
 161  *      called on each operation on devices of that class. The refcount
 162  *      of @cls is incremented.
 163  */
 164
 165 int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)
 166 {
 167         int err = 0;
 168
 169         mutex_lock(&sysdev_drivers_lock);
 170         if (cls && kset_get(&cls->kset)) {
 171                 list_add_tail(&drv->entry, &cls->drivers);
 172
 173                 /* If devices of this class already exist, tell the driver */
 174                 if (drv->add) {
 175                         struct sys_device *dev;
 176                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 177                                 drv->add(dev);
 178                 }
 179         } else {
 180                 err = -EINVAL;
 181                 printk(KERN_ERR "%s: invalid device class\n", __FUNCTION__);
 182                 WARN_ON(1);
 183         }
 184         mutex_unlock(&sysdev_drivers_lock);
 185         return err;
 186 }
 187
 188
 189 /**
 190  *      sysdev_driver_unregister - Remove an auxillary driver.
 191  *      @cls:   Class driver belongs to.
 192  *      @drv:   Driver.
 193  */
 194 void sysdev_driver_unregister(struct sysdev_class * cls,
 195                               struct sysdev_driver * drv)
 196 {
 197         mutex_lock(&sysdev_drivers_lock);
 198         list_del_init(&drv->entry);
 199         if (cls) {
 200                 if (drv->remove) {
 201                         struct sys_device *dev;
 202                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 203                                 drv->remove(dev);
 204                 }
 205                 kset_put(&cls->kset);
 206         }
 207         mutex_unlock(&sysdev_drivers_lock);
 208 }
 209
 210 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 211 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
 212
 213
 214
 215 /**
 216  *      sysdev_register - add a system device to the tree
 217  *      @sysdev:        device in question
 218  *
 219  */
 220 int sysdev_register(struct sys_device * sysdev)
 221 {
 222         int error;
 223         struct sysdev_class * cls = sysdev->cls;
 224
 225         if (!cls)
 226                 return -EINVAL;
 227
 228         pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));
 229
 230         /* Make sure the kset is set */
 231         sysdev->kobj.kset = &cls->kset;
 232
 233         /* Register the object */
 234         error = kobject_init_and_add(&sysdev->kobj, &ktype_sysdev, NULL,
 235                                      "%s%d", kobject_name(&cls->kset.kobj),
 236                                      sysdev->id);
 237
 238         if (!error) {
 239                 struct sysdev_driver * drv;
 240
 241                 mutex_lock(&sysdev_drivers_lock);
 242                 /* Generic notification is implicit, because it's that
 243                  * code that should have called us.
 244                  */
 245
 246                 /* Notify class auxillary drivers */
 247                 list_for_each_entry(drv, &cls->drivers, entry) {
 248                         if (drv->add)
 249                                 drv->add(sysdev);
 250                 }
 251                 mutex_unlock(&sysdev_drivers_lock);
 252         }
 253         kobject_uevent(&sysdev->kobj, KOBJ_ADD);
 254         return error;
 255 }
 256
 257 void sysdev_unregister(struct sys_device * sysdev)
 258 {
 259         struct sysdev_driver * drv;
 260
 261         mutex_lock(&sysdev_drivers_lock);
 262         list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 263                 if (drv->remove)
 264                         drv->remove(sysdev);
 265         }
 266         mutex_unlock(&sysdev_drivers_lock);
 267
 268         kobject_put(&sysdev->kobj);
 269 }
 270
 271
 272
 273 /**
 274  *      sysdev_shutdown - Shut down all system devices.
 275  *
 276  *      Loop over each class of system devices, and the devices in each
 277  *      of those classes. For each device, we call the shutdown method for
 278  *      each driver registered for the device - the auxillaries,
 279  *      and the class driver.
 280  *
 281  *      Note: The list is iterated in reverse order, so that we shut down
 282  *      child devices before we shut down thier parents. The list ordering
 283  *      is guaranteed by virtue of the fact that child devices are registered
 284  *      after their parents.
 285  */
 286
 287 void sysdev_shutdown(void)
 288 {
 289         struct sysdev_class * cls;
 290
 291         pr_debug("Shutting Down System Devices\n");
 292
 293         mutex_lock(&sysdev_drivers_lock);
 294         list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
 295                 struct sys_device * sysdev;
 296
 297                 pr_debug("Shutting down type '%s':\n",
 298                          kobject_name(&cls->kset.kobj));
 299
 300                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 301                         struct sysdev_driver * drv;
 302                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 303
 304                         /* Call auxillary drivers first */
 305                         list_for_each_entry(drv, &cls->drivers, entry) {
 306                                 if (drv->shutdown)
 307                                         drv->shutdown(sysdev);
 308                         }
 309
 310                         /* Now call the generic one */
 311                         if (cls->shutdown)
 312                                 cls->shutdown(sysdev);
 313                 }
 314         }
 315         mutex_unlock(&sysdev_drivers_lock);
 316 }
 317
 318 static void __sysdev_resume(struct sys_device *dev)
 319 {
 320         struct sysdev_class *cls = dev->cls;
 321         struct sysdev_driver *drv;
 322
 323         /* First, call the class-specific one */
 324         if (cls->resume)
 325                 cls->resume(dev);
 326
 327         /* Call auxillary drivers next. */
 328         list_for_each_entry(drv, &cls->drivers, entry) {
 329                 if (drv->resume)
 330                         drv->resume(dev);
 331         }
 332 }
 333
 334 /**
 335  *      sysdev_suspend - Suspend all system devices.
 336  *      @state:         Power state to enter.
 337  *
 338  *      We perform an almost identical operation as sys_device_shutdown()
 339  *      above, though calling ->suspend() instead. Interrupts are disabled
 340  *      when this called. Devices are responsible for both saving state and
 341  *      quiescing or powering down the device.
 342  *
 343  *      This is only called by the device PM core, so we let them handle
 344  *      all synchronization.
 345  */
 346
 347 int sysdev_suspend(pm_message_t state)
 348 {
 349         struct sysdev_class * cls;
 350         struct sys_device *sysdev, *err_dev;
 351         struct sysdev_driver *drv, *err_drv;
 352         int ret;
 353
 354         pr_debug("Suspending System Devices\n");
 355
 356         list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
 357                 pr_debug("Suspending type '%s':\n",
 358                          kobject_name(&cls->kset.kobj));
 359
 360                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 361                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 362
 363                         /* Call auxillary drivers first */
 364                         list_for_each_entry(drv, &cls->drivers, entry) {
 365                                 if (drv->suspend) {
 366                                         ret = drv->suspend(sysdev, state);
 367                                         if (ret)
 368                                                 goto aux_driver;
 369                                 }
 370                         }
 371
 372                         /* Now call the generic one */
 373                         if (cls->suspend) {
 374                                 ret = cls->suspend(sysdev, state);
 375                                 if (ret)
 376                                         goto cls_driver;
 377                         }
 378                 }
 379         }
 380         return 0;
 381         /* resume current sysdev */
 382 cls_driver:
 383         drv = NULL;
 384         printk(KERN_ERR "Class suspend failed for %s\n",
 385                 kobject_name(&sysdev->kobj));
 386
 387 aux_driver:
 388         if (drv)
 389                 printk(KERN_ERR "Class driver suspend failed for %s\n",
 390                                 kobject_name(&sysdev->kobj));
 391         list_for_each_entry(err_drv, &cls->drivers, entry) {
 392                 if (err_drv == drv)
 393                         break;
 394                 if (err_drv->resume)
 395                         err_drv->resume(sysdev);
 396         }
 397
 398         /* resume other sysdevs in current class */
 399         list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 400                 if (err_dev == sysdev)
 401                         break;
 402                 pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 403                 __sysdev_resume(err_dev);
 404         }
 405
 406         /* resume other classes */
 407         list_for_each_entry_continue(cls, &system_kset->list, kset.kobj.entry) {
 408                 list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 409                         pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 410                         __sysdev_resume(err_dev);
 411                 }
 412         }
 413         return ret;
 414 }
 415
 416
 417 /**
 418  *      sysdev_resume - Bring system devices back to life.
 419  *
 420  *      Similar to sys_device_suspend(), but we iterate the list forwards
 421  *      to guarantee that parent devices are resumed before their children.
 422  *
 423  *      Note: Interrupts are disabled when called.
 424  */
 425
 426 int sysdev_resume(void)
 427 {
 428         struct sysdev_class * cls;
 429
 430         pr_debug("Resuming System Devices\n");
 431
 432         list_for_each_entry(cls, &system_kset->list, kset.kobj.entry) {
 433                 struct sys_device * sysdev;
 434
 435                 pr_debug("Resuming type '%s':\n",
 436                          kobject_name(&cls->kset.kobj));
 437
 438                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 439                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 440
 441                         __sysdev_resume(sysdev);
 442                 }
 443         }
 444         return 0;
 445 }
 446
 447
 448 int __init system_bus_init(void)
 449 {
 450         system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
 451         if (!system_kset)
 452                 return -ENOMEM;
 453         return 0;
 454 }
 455
 456 EXPORT_SYMBOL_GPL(sysdev_register);
 457 EXPORT_SYMBOL_GPL(sysdev_unregister);