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 #include <linux/pm.h>
  24 #include <linux/device.h>
  25 #include <asm/semaphore.h>
  26
  27 #include "base.h"
  28
  29 extern struct subsystem devices_subsys;
  30
  31 #define to_sysdev(k) container_of(k, struct sys_device, kobj)
  32 #define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)
  33
  34
  35 static ssize_t
  36 sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
  37 {
  38         struct sys_device * sysdev = to_sysdev(kobj);
  39         struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
  40
  41         if (sysdev_attr->show)
  42                 return sysdev_attr->show(sysdev, buffer);
  43         return -EIO;
  44 }
  45
  46
  47 static ssize_t
  48 sysdev_store(struct kobject * kobj, struct attribute * attr,
  49              const char * buffer, size_t count)
  50 {
  51         struct sys_device * sysdev = to_sysdev(kobj);
  52         struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
  53
  54         if (sysdev_attr->store)
  55                 return sysdev_attr->store(sysdev, buffer, count);
  56         return -EIO;
  57 }
  58
  59 static struct sysfs_ops sysfs_ops = {
  60         .show   = sysdev_show,
  61         .store  = sysdev_store,
  62 };
  63
  64 static struct kobj_type ktype_sysdev = {
  65         .sysfs_ops      = &sysfs_ops,
  66 };
  67
  68
  69 int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)
  70 {
  71         return sysfs_create_file(&s->kobj, &a->attr);
  72 }
  73
  74
  75 void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)
  76 {
  77         sysfs_remove_file(&s->kobj, &a->attr);
  78 }
  79
  80 EXPORT_SYMBOL_GPL(sysdev_create_file);
  81 EXPORT_SYMBOL_GPL(sysdev_remove_file);
  82
  83 /*
  84  * declare system_subsys
  85  */
  86 static decl_subsys(system, &ktype_sysdev, NULL);
  87
  88 int sysdev_class_register(struct sysdev_class * cls)
  89 {
  90         pr_debug("Registering sysdev class '%s'\n",
  91                  kobject_name(&cls->kset.kobj));
  92         INIT_LIST_HEAD(&cls->drivers);
  93         cls->kset.subsys = &system_subsys;
  94         kset_set_kset_s(cls, system_subsys);
  95         return kset_register(&cls->kset);
  96 }
  97
  98 void sysdev_class_unregister(struct sysdev_class * cls)
  99 {
 100         pr_debug("Unregistering sysdev class '%s'\n",
 101                  kobject_name(&cls->kset.kobj));
 102         kset_unregister(&cls->kset);
 103 }
 104
 105 EXPORT_SYMBOL_GPL(sysdev_class_register);
 106 EXPORT_SYMBOL_GPL(sysdev_class_unregister);
 107
 108
 109 static LIST_HEAD(sysdev_drivers);
 110 static DECLARE_MUTEX(sysdev_drivers_lock);
 111
 112 /**
 113  *      sysdev_driver_register - Register auxillary driver
 114  *      @cls:   Device class driver belongs to.
 115  *      @drv:   Driver.
 116  *
 117  *      If @cls is valid, then @drv is inserted into @cls->drivers to be
 118  *      called on each operation on devices of that class. The refcount
 119  *      of @cls is incremented.
 120  *      Otherwise, @drv is inserted into sysdev_drivers, and called for
 121  *      each device.
 122  */
 123
 124 int sysdev_driver_register(struct sysdev_class * cls,
 125                            struct sysdev_driver * drv)
 126 {
 127         down(&sysdev_drivers_lock);
 128         if (cls && kset_get(&cls->kset)) {
 129                 list_add_tail(&drv->entry, &cls->drivers);
 130
 131                 /* If devices of this class already exist, tell the driver */
 132                 if (drv->add) {
 133                         struct sys_device *dev;
 134                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 135                                 drv->add(dev);
 136                 }
 137         } else
 138                 list_add_tail(&drv->entry, &sysdev_drivers);
 139         up(&sysdev_drivers_lock);
 140         return 0;
 141 }
 142
 143
 144 /**
 145  *      sysdev_driver_unregister - Remove an auxillary driver.
 146  *      @cls:   Class driver belongs to.
 147  *      @drv:   Driver.
 148  */
 149 void sysdev_driver_unregister(struct sysdev_class * cls,
 150                               struct sysdev_driver * drv)
 151 {
 152         down(&sysdev_drivers_lock);
 153         list_del_init(&drv->entry);
 154         if (cls) {
 155                 if (drv->remove) {
 156                         struct sys_device *dev;
 157                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 158                                 drv->remove(dev);
 159                 }
 160                 kset_put(&cls->kset);
 161         }
 162         up(&sysdev_drivers_lock);
 163 }
 164
 165 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 166 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
 167
 168
 169
 170 /**
 171  *      sysdev_register - add a system device to the tree
 172  *      @sysdev:        device in question
 173  *
 174  */
 175 int sysdev_register(struct sys_device * sysdev)
 176 {
 177         int error;
 178         struct sysdev_class * cls = sysdev->cls;
 179
 180         if (!cls)
 181                 return -EINVAL;
 182
 183         /* Make sure the kset is set */
 184         sysdev->kobj.kset = &cls->kset;
 185
 186         /* But make sure we point to the right type for sysfs translation */
 187         sysdev->kobj.ktype = &ktype_sysdev;
 188         error = kobject_set_name(&sysdev->kobj, "%s%d",
 189                          kobject_name(&cls->kset.kobj), sysdev->id);
 190         if (error)
 191                 return error;
 192
 193         pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));
 194
 195         /* Register the object */
 196         error = kobject_register(&sysdev->kobj);
 197
 198         if (!error) {
 199                 struct sysdev_driver * drv;
 200
 201                 down(&sysdev_drivers_lock);
 202                 /* Generic notification is implicit, because it's that
 203                  * code that should have called us.
 204                  */
 205
 206                 /* Notify global drivers */
 207                 list_for_each_entry(drv, &sysdev_drivers, entry) {
 208                         if (drv->add)
 209                                 drv->add(sysdev);
 210                 }
 211
 212                 /* Notify class auxillary drivers */
 213                 list_for_each_entry(drv, &cls->drivers, entry) {
 214                         if (drv->add)
 215                                 drv->add(sysdev);
 216                 }
 217                 up(&sysdev_drivers_lock);
 218         }
 219         return error;
 220 }
 221
 222 void sysdev_unregister(struct sys_device * sysdev)
 223 {
 224         struct sysdev_driver * drv;
 225
 226         down(&sysdev_drivers_lock);
 227         list_for_each_entry(drv, &sysdev_drivers, entry) {
 228                 if (drv->remove)
 229                         drv->remove(sysdev);
 230         }
 231
 232         list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 233                 if (drv->remove)
 234                         drv->remove(sysdev);
 235         }
 236         up(&sysdev_drivers_lock);
 237
 238         kobject_unregister(&sysdev->kobj);
 239 }
 240
 241
 242
 243 /**
 244  *      sysdev_shutdown - Shut down all system devices.
 245  *
 246  *      Loop over each class of system devices, and the devices in each
 247  *      of those classes. For each device, we call the shutdown method for
 248  *      each driver registered for the device - the globals, the auxillaries,
 249  *      and the class driver.
 250  *
 251  *      Note: The list is iterated in reverse order, so that we shut down
 252  *      child devices before we shut down thier parents. The list ordering
 253  *      is guaranteed by virtue of the fact that child devices are registered
 254  *      after their parents.
 255  */
 256
 257 void sysdev_shutdown(void)
 258 {
 259         struct sysdev_class * cls;
 260
 261         pr_debug("Shutting Down System Devices\n");
 262
 263         down(&sysdev_drivers_lock);
 264         list_for_each_entry_reverse(cls, &system_subsys.kset.list,
 265                                     kset.kobj.entry) {
 266                 struct sys_device * sysdev;
 267
 268                 pr_debug("Shutting down type '%s':\n",
 269                          kobject_name(&cls->kset.kobj));
 270
 271                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 272                         struct sysdev_driver * drv;
 273                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 274
 275                         /* Call global drivers first. */
 276                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 277                                 if (drv->shutdown)
 278                                         drv->shutdown(sysdev);
 279                         }
 280
 281                         /* Call auxillary drivers next. */
 282                         list_for_each_entry(drv, &cls->drivers, entry) {
 283                                 if (drv->shutdown)
 284                                         drv->shutdown(sysdev);
 285                         }
 286
 287                         /* Now call the generic one */
 288                         if (cls->shutdown)
 289                                 cls->shutdown(sysdev);
 290                 }
 291         }
 292         up(&sysdev_drivers_lock);
 293 }
 294
 295 static void __sysdev_resume(struct sys_device *dev)
 296 {
 297         struct sysdev_class *cls = dev->cls;
 298         struct sysdev_driver *drv;
 299
 300         /* First, call the class-specific one */
 301         if (cls->resume)
 302                 cls->resume(dev);
 303
 304         /* Call auxillary drivers next. */
 305         list_for_each_entry(drv, &cls->drivers, entry) {
 306                 if (drv->resume)
 307                         drv->resume(dev);
 308         }
 309
 310         /* Call global drivers. */
 311         list_for_each_entry(drv, &sysdev_drivers, entry) {
 312                 if (drv->resume)
 313                         drv->resume(dev);
 314         }
 315 }
 316
 317 /**
 318  *      sysdev_suspend - Suspend all system devices.
 319  *      @state:         Power state to enter.
 320  *
 321  *      We perform an almost identical operation as sys_device_shutdown()
 322  *      above, though calling ->suspend() instead. Interrupts are disabled
 323  *      when this called. Devices are responsible for both saving state and
 324  *      quiescing or powering down the device.
 325  *
 326  *      This is only called by the device PM core, so we let them handle
 327  *      all synchronization.
 328  */
 329
 330 int sysdev_suspend(pm_message_t state)
 331 {
 332         struct sysdev_class * cls;
 333         struct sys_device *sysdev, *err_dev;
 334         struct sysdev_driver *drv, *err_drv;
 335         int ret;
 336
 337         pr_debug("Suspending System Devices\n");
 338
 339         list_for_each_entry_reverse(cls, &system_subsys.kset.list,
 340                                     kset.kobj.entry) {
 341
 342                 pr_debug("Suspending type '%s':\n",
 343                          kobject_name(&cls->kset.kobj));
 344
 345                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 346                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 347
 348                         /* Call global drivers first. */
 349                         list_for_each_entry(drv, &sysdev_drivers, entry) {
 350                                 if (drv->suspend) {
 351                                         ret = drv->suspend(sysdev, state);
 352                                         if (ret)
 353                                                 goto gbl_driver;
 354                                 }
 355                         }
 356
 357                         /* Call auxillary drivers next. */
 358                         list_for_each_entry(drv, &cls->drivers, entry) {
 359                                 if (drv->suspend) {
 360                                         ret = drv->suspend(sysdev, state);
 361                                         if (ret)
 362                                                 goto aux_driver;
 363                                 }
 364                         }
 365
 366                         /* Now call the generic one */
 367                         if (cls->suspend) {
 368                                 ret = cls->suspend(sysdev, state);
 369                                 if (ret)
 370                                         goto cls_driver;
 371                         }
 372                 }
 373         }
 374         return 0;
 375         /* resume current sysdev */
 376 cls_driver:
 377         drv = NULL;
 378         printk(KERN_ERR "Class suspend failed for %s\n",
 379                 kobject_name(&sysdev->kobj));
 380
 381 aux_driver:
 382         if (drv)
 383                 printk(KERN_ERR "Class driver suspend failed for %s\n",
 384                                 kobject_name(&sysdev->kobj));
 385         list_for_each_entry(err_drv, &cls->drivers, entry) {
 386                 if (err_drv == drv)
 387                         break;
 388                 if (err_drv->resume)
 389                         err_drv->resume(sysdev);
 390         }
 391         drv = NULL;
 392
 393 gbl_driver:
 394         if (drv)
 395                 printk(KERN_ERR "sysdev driver suspend failed for %s\n",
 396                                 kobject_name(&sysdev->kobj));
 397         list_for_each_entry(err_drv, &sysdev_drivers, entry) {
 398                 if (err_drv == drv)
 399                         break;
 400                 if (err_drv->resume)
 401                         err_drv->resume(sysdev);
 402         }
 403         /* resume other sysdevs in current class */
 404         list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 405                 if (err_dev == sysdev)
 406                         break;
 407                 pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 408                 __sysdev_resume(err_dev);
 409         }
 410
 411         /* resume other classes */
 412         list_for_each_entry_continue(cls, &system_subsys.kset.list,
 413                                         kset.kobj.entry) {
 414                 list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 415                         pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 416                         __sysdev_resume(err_dev);
 417                 }
 418         }
 419         return ret;
 420 }
 421
 422
 423 /**
 424  *      sysdev_resume - Bring system devices back to life.
 425  *
 426  *      Similar to sys_device_suspend(), but we iterate the list forwards
 427  *      to guarantee that parent devices are resumed before their children.
 428  *
 429  *      Note: Interrupts are disabled when called.
 430  */
 431
 432 int sysdev_resume(void)
 433 {
 434         struct sysdev_class * cls;
 435
 436         pr_debug("Resuming System Devices\n");
 437
 438         list_for_each_entry(cls, &system_subsys.kset.list, kset.kobj.entry) {
 439                 struct sys_device * sysdev;
 440
 441                 pr_debug("Resuming type '%s':\n",
 442                          kobject_name(&cls->kset.kobj));
 443
 444                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 445                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 446
 447                         __sysdev_resume(sysdev);
 448                 }
 449         }
 450         return 0;
 451 }
 452
 453
 454 int __init system_bus_init(void)
 455 {
 456         system_subsys.kset.kobj.parent = &devices_subsys.kset.kobj;
 457         return subsystem_register(&system_subsys);
 458 }
 459
 460 EXPORT_SYMBOL_GPL(sysdev_register);
 461 EXPORT_SYMBOL_GPL(sysdev_unregister);