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