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         memset(&cls->kset.kobj, 0x00, sizeof(struct kobject));
 137         cls->kset.kobj.parent = &system_kset->kobj;
 138         cls->kset.kobj.ktype = &ktype_sysdev_class;
 139         cls->kset.kobj.kset = system_kset;
 140         kobject_set_name(&cls->kset.kobj, cls->name);
 141         return kset_register(&cls->kset);
 142 }
 143
 144 void sysdev_class_unregister(struct sysdev_class * cls)
 145 {
 146         pr_debug("Unregistering sysdev class '%s'\n",
 147                  kobject_name(&cls->kset.kobj));
 148         kset_unregister(&cls->kset);
 149 }
 150
 151 EXPORT_SYMBOL_GPL(sysdev_class_register);
 152 EXPORT_SYMBOL_GPL(sysdev_class_unregister);
 153
 154 static DEFINE_MUTEX(sysdev_drivers_lock);
 155
 156 /**
 157  *      sysdev_driver_register - Register auxillary driver
 158  *      @cls:   Device class driver belongs to.
 159  *      @drv:   Driver.
 160  *
 161  *      @drv is inserted into @cls->drivers to be
 162  *      called on each operation on devices of that class. The refcount
 163  *      of @cls is incremented.
 164  */
 165
 166 int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)
 167 {
 168         int err = 0;
 169
 170         if (!cls) {
 171                 printk(KERN_WARNING "sysdev: invalid class passed to "
 172                         "sysdev_driver_register!\n");
 173                 WARN_ON(1);
 174                 return -EINVAL;
 175         }
 176
 177         /* Check whether this driver has already been added to a class. */
 178         if ((drv->entry.next != drv->entry.prev) ||
 179             (drv->entry.next != NULL)) {
 180                 printk(KERN_WARNING "sysdev: class %s: driver (%p) has already"
 181                         " been registered to a class, something is wrong, but "
 182                         "will forge on!\n", cls->name, drv);
 183                 WARN_ON(1);
 184         }
 185
 186         mutex_lock(&sysdev_drivers_lock);
 187         if (cls && kset_get(&cls->kset)) {
 188                 list_add_tail(&drv->entry, &cls->drivers);
 189
 190                 /* If devices of this class already exist, tell the driver */
 191                 if (drv->add) {
 192                         struct sys_device *dev;
 193                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 194                                 drv->add(dev);
 195                 }
 196         } else {
 197                 err = -EINVAL;
 198                 printk(KERN_ERR "%s: invalid device class\n", __func__);
 199                 WARN_ON(1);
 200         }
 201         mutex_unlock(&sysdev_drivers_lock);
 202         return err;
 203 }
 204
 205
 206 /**
 207  *      sysdev_driver_unregister - Remove an auxillary driver.
 208  *      @cls:   Class driver belongs to.
 209  *      @drv:   Driver.
 210  */
 211 void sysdev_driver_unregister(struct sysdev_class * cls,
 212                               struct sysdev_driver * drv)
 213 {
 214         mutex_lock(&sysdev_drivers_lock);
 215         list_del_init(&drv->entry);
 216         if (cls) {
 217                 if (drv->remove) {
 218                         struct sys_device *dev;
 219                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 220                                 drv->remove(dev);
 221                 }
 222                 kset_put(&cls->kset);
 223         }
 224         mutex_unlock(&sysdev_drivers_lock);
 225 }
 226
 227 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 228 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
 229
 230
 231
 232 /**
 233  *      sysdev_register - add a system device to the tree
 234  *      @sysdev:        device in question
 235  *
 236  */
 237 int sysdev_register(struct sys_device * sysdev)
 238 {
 239         int error;
 240         struct sysdev_class * cls = sysdev->cls;
 241
 242         if (!cls)
 243                 return -EINVAL;
 244
 245         pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));
 246
 247         /* initialize the kobject to 0, in case it had previously been used */
 248         memset(&sysdev->kobj, 0x00, sizeof(struct kobject));
 249
 250         /* Make sure the kset is set */
 251         sysdev->kobj.kset = &cls->kset;
 252
 253         /* Register the object */
 254         error = kobject_init_and_add(&sysdev->kobj, &ktype_sysdev, NULL,
 255                                      "%s%d", kobject_name(&cls->kset.kobj),
 256                                      sysdev->id);
 257
 258         if (!error) {
 259                 struct sysdev_driver * drv;
 260
 261                 mutex_lock(&sysdev_drivers_lock);
 262                 /* Generic notification is implicit, because it's that
 263                  * code that should have called us.
 264                  */
 265
 266                 /* Notify class auxillary drivers */
 267                 list_for_each_entry(drv, &cls->drivers, entry) {
 268                         if (drv->add)
 269                                 drv->add(sysdev);
 270                 }
 271                 mutex_unlock(&sysdev_drivers_lock);
 272         }
 273         kobject_uevent(&sysdev->kobj, KOBJ_ADD);
 274         return error;
 275 }
 276
 277 void sysdev_unregister(struct sys_device * sysdev)
 278 {
 279         struct sysdev_driver * drv;
 280
 281         mutex_lock(&sysdev_drivers_lock);
 282         list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 283                 if (drv->remove)
 284                         drv->remove(sysdev);
 285         }
 286         mutex_unlock(&sysdev_drivers_lock);
 287
 288         kobject_put(&sysdev->kobj);
 289 }
 290
 291
 292
 293 /**
 294  *      sysdev_shutdown - Shut down all system devices.
 295  *
 296  *      Loop over each class of system devices, and the devices in each
 297  *      of those classes. For each device, we call the shutdown method for
 298  *      each driver registered for the device - the auxillaries,
 299  *      and the class driver.
 300  *
 301  *      Note: The list is iterated in reverse order, so that we shut down
 302  *      child devices before we shut down thier parents. The list ordering
 303  *      is guaranteed by virtue of the fact that child devices are registered
 304  *      after their parents.
 305  */
 306
 307 void sysdev_shutdown(void)
 308 {
 309         struct sysdev_class * cls;
 310
 311         pr_debug("Shutting Down System Devices\n");
 312
 313         mutex_lock(&sysdev_drivers_lock);
 314         list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
 315                 struct sys_device * sysdev;
 316
 317                 pr_debug("Shutting down type '%s':\n",
 318                          kobject_name(&cls->kset.kobj));
 319
 320                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 321                         struct sysdev_driver * drv;
 322                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 323
 324                         /* Call auxillary drivers first */
 325                         list_for_each_entry(drv, &cls->drivers, entry) {
 326                                 if (drv->shutdown)
 327                                         drv->shutdown(sysdev);
 328                         }
 329
 330                         /* Now call the generic one */
 331                         if (cls->shutdown)
 332                                 cls->shutdown(sysdev);
 333                 }
 334         }
 335         mutex_unlock(&sysdev_drivers_lock);
 336 }
 337
 338 static void __sysdev_resume(struct sys_device *dev)
 339 {
 340         struct sysdev_class *cls = dev->cls;
 341         struct sysdev_driver *drv;
 342
 343         /* First, call the class-specific one */
 344         if (cls->resume)
 345                 cls->resume(dev);
 346
 347         /* Call auxillary drivers next. */
 348         list_for_each_entry(drv, &cls->drivers, entry) {
 349                 if (drv->resume)
 350                         drv->resume(dev);
 351         }
 352 }
 353
 354 /**
 355  *      sysdev_suspend - Suspend all system devices.
 356  *      @state:         Power state to enter.
 357  *
 358  *      We perform an almost identical operation as sys_device_shutdown()
 359  *      above, though calling ->suspend() instead. Interrupts are disabled
 360  *      when this called. Devices are responsible for both saving state and
 361  *      quiescing or powering down the device.
 362  *
 363  *      This is only called by the device PM core, so we let them handle
 364  *      all synchronization.
 365  */
 366
 367 int sysdev_suspend(pm_message_t state)
 368 {
 369         struct sysdev_class * cls;
 370         struct sys_device *sysdev, *err_dev;
 371         struct sysdev_driver *drv, *err_drv;
 372         int ret;
 373
 374         pr_debug("Suspending System Devices\n");
 375
 376         list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
 377                 pr_debug("Suspending type '%s':\n",
 378                          kobject_name(&cls->kset.kobj));
 379
 380                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 381                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 382
 383                         /* Call auxillary drivers first */
 384                         list_for_each_entry(drv, &cls->drivers, entry) {
 385                                 if (drv->suspend) {
 386                                         ret = drv->suspend(sysdev, state);
 387                                         if (ret)
 388                                                 goto aux_driver;
 389                                 }
 390                         }
 391
 392                         /* Now call the generic one */
 393                         if (cls->suspend) {
 394                                 ret = cls->suspend(sysdev, state);
 395                                 if (ret)
 396                                         goto cls_driver;
 397                         }
 398                 }
 399         }
 400         return 0;
 401         /* resume current sysdev */
 402 cls_driver:
 403         drv = NULL;
 404         printk(KERN_ERR "Class suspend failed for %s\n",
 405                 kobject_name(&sysdev->kobj));
 406
 407 aux_driver:
 408         if (drv)
 409                 printk(KERN_ERR "Class driver suspend failed for %s\n",
 410                                 kobject_name(&sysdev->kobj));
 411         list_for_each_entry(err_drv, &cls->drivers, entry) {
 412                 if (err_drv == drv)
 413                         break;
 414                 if (err_drv->resume)
 415                         err_drv->resume(sysdev);
 416         }
 417
 418         /* resume other sysdevs in current class */
 419         list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 420                 if (err_dev == sysdev)
 421                         break;
 422                 pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 423                 __sysdev_resume(err_dev);
 424         }
 425
 426         /* resume other classes */
 427         list_for_each_entry_continue(cls, &system_kset->list, kset.kobj.entry) {
 428                 list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 429                         pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 430                         __sysdev_resume(err_dev);
 431                 }
 432         }
 433         return ret;
 434 }
 435
 436
 437 /**
 438  *      sysdev_resume - Bring system devices back to life.
 439  *
 440  *      Similar to sys_device_suspend(), but we iterate the list forwards
 441  *      to guarantee that parent devices are resumed before their children.
 442  *
 443  *      Note: Interrupts are disabled when called.
 444  */
 445
 446 int sysdev_resume(void)
 447 {
 448         struct sysdev_class * cls;
 449
 450         pr_debug("Resuming System Devices\n");
 451
 452         list_for_each_entry(cls, &system_kset->list, kset.kobj.entry) {
 453                 struct sys_device * sysdev;
 454
 455                 pr_debug("Resuming type '%s':\n",
 456                          kobject_name(&cls->kset.kobj));
 457
 458                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 459                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 460
 461                         __sysdev_resume(sysdev);
 462                 }
 463         }
 464         return 0;
 465 }
 466
 467
 468 int __init system_bus_init(void)
 469 {
 470         system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
 471         if (!system_kset)
 472                 return -ENOMEM;
 473         return 0;
 474 }
 475
 476 EXPORT_SYMBOL_GPL(sysdev_register);
 477 EXPORT_SYMBOL_GPL(sysdev_unregister);