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, sysdev_attr, 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, sysdev_attr, 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", cls->name);
 134
 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 && !list_empty(&drv->entry)) {
 179                 printk(KERN_WARNING "sysdev: class %s: driver (%p) has already"
 180                         " been registered to a class, something is wrong, but "
 181                         "will forge on!\n", cls->name, drv);
 182                 WARN_ON(1);
 183         }
 184
 185         mutex_lock(&sysdev_drivers_lock);
 186         if (cls && kset_get(&cls->kset)) {
 187                 list_add_tail(&drv->entry, &cls->drivers);
 188
 189                 /* If devices of this class already exist, tell the driver */
 190                 if (drv->add) {
 191                         struct sys_device *dev;
 192                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 193                                 drv->add(dev);
 194                 }
 195         } else {
 196                 err = -EINVAL;
 197                 printk(KERN_ERR "%s: invalid device class\n", __func__);
 198                 WARN_ON(1);
 199         }
 200         mutex_unlock(&sysdev_drivers_lock);
 201         return err;
 202 }
 203
 204
 205 /**
 206  *      sysdev_driver_unregister - Remove an auxillary driver.
 207  *      @cls:   Class driver belongs to.
 208  *      @drv:   Driver.
 209  */
 210 void sysdev_driver_unregister(struct sysdev_class * cls,
 211                               struct sysdev_driver * drv)
 212 {
 213         mutex_lock(&sysdev_drivers_lock);
 214         list_del_init(&drv->entry);
 215         if (cls) {
 216                 if (drv->remove) {
 217                         struct sys_device *dev;
 218                         list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 219                                 drv->remove(dev);
 220                 }
 221                 kset_put(&cls->kset);
 222         }
 223         mutex_unlock(&sysdev_drivers_lock);
 224 }
 225
 226 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 227 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
 228
 229
 230
 231 /**
 232  *      sysdev_register - add a system device to the tree
 233  *      @sysdev:        device in question
 234  *
 235  */
 236 int sysdev_register(struct sys_device * sysdev)
 237 {
 238         int error;
 239         struct sysdev_class * cls = sysdev->cls;
 240
 241         if (!cls)
 242                 return -EINVAL;
 243
 244         pr_debug("Registering sys device of class '%s'\n",
 245                  kobject_name(&cls->kset.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                 pr_debug("Registering sys device '%s'\n",
 262                          kobject_name(&sysdev->kobj));
 263
 264                 mutex_lock(&sysdev_drivers_lock);
 265                 /* Generic notification is implicit, because it's that
 266                  * code that should have called us.
 267                  */
 268
 269                 /* Notify class auxillary drivers */
 270                 list_for_each_entry(drv, &cls->drivers, entry) {
 271                         if (drv->add)
 272                                 drv->add(sysdev);
 273                 }
 274                 mutex_unlock(&sysdev_drivers_lock);
 275         }
 276
 277         kobject_uevent(&sysdev->kobj, KOBJ_ADD);
 278         return error;
 279 }
 280
 281 void sysdev_unregister(struct sys_device * sysdev)
 282 {
 283         struct sysdev_driver * drv;
 284
 285         mutex_lock(&sysdev_drivers_lock);
 286         list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 287                 if (drv->remove)
 288                         drv->remove(sysdev);
 289         }
 290         mutex_unlock(&sysdev_drivers_lock);
 291
 292         kobject_put(&sysdev->kobj);
 293 }
 294
 295
 296
 297 /**
 298  *      sysdev_shutdown - Shut down all system devices.
 299  *
 300  *      Loop over each class of system devices, and the devices in each
 301  *      of those classes. For each device, we call the shutdown method for
 302  *      each driver registered for the device - the auxillaries,
 303  *      and the class driver.
 304  *
 305  *      Note: The list is iterated in reverse order, so that we shut down
 306  *      child devices before we shut down thier parents. The list ordering
 307  *      is guaranteed by virtue of the fact that child devices are registered
 308  *      after their parents.
 309  */
 310
 311 void sysdev_shutdown(void)
 312 {
 313         struct sysdev_class * cls;
 314
 315         pr_debug("Shutting Down System Devices\n");
 316
 317         mutex_lock(&sysdev_drivers_lock);
 318         list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
 319                 struct sys_device * sysdev;
 320
 321                 pr_debug("Shutting down type '%s':\n",
 322                          kobject_name(&cls->kset.kobj));
 323
 324                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 325                         struct sysdev_driver * drv;
 326                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 327
 328                         /* Call auxillary drivers first */
 329                         list_for_each_entry(drv, &cls->drivers, entry) {
 330                                 if (drv->shutdown)
 331                                         drv->shutdown(sysdev);
 332                         }
 333
 334                         /* Now call the generic one */
 335                         if (cls->shutdown)
 336                                 cls->shutdown(sysdev);
 337                 }
 338         }
 339         mutex_unlock(&sysdev_drivers_lock);
 340 }
 341
 342 static void __sysdev_resume(struct sys_device *dev)
 343 {
 344         struct sysdev_class *cls = dev->cls;
 345         struct sysdev_driver *drv;
 346
 347         /* First, call the class-specific one */
 348         if (cls->resume)
 349                 cls->resume(dev);
 350
 351         /* Call auxillary drivers next. */
 352         list_for_each_entry(drv, &cls->drivers, entry) {
 353                 if (drv->resume)
 354                         drv->resume(dev);
 355         }
 356 }
 357
 358 /**
 359  *      sysdev_suspend - Suspend all system devices.
 360  *      @state:         Power state to enter.
 361  *
 362  *      We perform an almost identical operation as sys_device_shutdown()
 363  *      above, though calling ->suspend() instead. Interrupts are disabled
 364  *      when this called. Devices are responsible for both saving state and
 365  *      quiescing or powering down the device.
 366  *
 367  *      This is only called by the device PM core, so we let them handle
 368  *      all synchronization.
 369  */
 370
 371 int sysdev_suspend(pm_message_t state)
 372 {
 373         struct sysdev_class * cls;
 374         struct sys_device *sysdev, *err_dev;
 375         struct sysdev_driver *drv, *err_drv;
 376         int ret;
 377
 378         pr_debug("Suspending System Devices\n");
 379
 380         list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
 381                 pr_debug("Suspending type '%s':\n",
 382                          kobject_name(&cls->kset.kobj));
 383
 384                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 385                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 386
 387                         /* Call auxillary drivers first */
 388                         list_for_each_entry(drv, &cls->drivers, entry) {
 389                                 if (drv->suspend) {
 390                                         ret = drv->suspend(sysdev, state);
 391                                         if (ret)
 392                                                 goto aux_driver;
 393                                 }
 394                         }
 395
 396                         /* Now call the generic one */
 397                         if (cls->suspend) {
 398                                 ret = cls->suspend(sysdev, state);
 399                                 if (ret)
 400                                         goto cls_driver;
 401                         }
 402                 }
 403         }
 404         return 0;
 405         /* resume current sysdev */
 406 cls_driver:
 407         drv = NULL;
 408         printk(KERN_ERR "Class suspend failed for %s\n",
 409                 kobject_name(&sysdev->kobj));
 410
 411 aux_driver:
 412         if (drv)
 413                 printk(KERN_ERR "Class driver suspend failed for %s\n",
 414                                 kobject_name(&sysdev->kobj));
 415         list_for_each_entry(err_drv, &cls->drivers, entry) {
 416                 if (err_drv == drv)
 417                         break;
 418                 if (err_drv->resume)
 419                         err_drv->resume(sysdev);
 420         }
 421
 422         /* resume other sysdevs in current class */
 423         list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 424                 if (err_dev == sysdev)
 425                         break;
 426                 pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 427                 __sysdev_resume(err_dev);
 428         }
 429
 430         /* resume other classes */
 431         list_for_each_entry_continue(cls, &system_kset->list, kset.kobj.entry) {
 432                 list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 433                         pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 434                         __sysdev_resume(err_dev);
 435                 }
 436         }
 437         return ret;
 438 }
 439
 440
 441 /**
 442  *      sysdev_resume - Bring system devices back to life.
 443  *
 444  *      Similar to sys_device_suspend(), but we iterate the list forwards
 445  *      to guarantee that parent devices are resumed before their children.
 446  *
 447  *      Note: Interrupts are disabled when called.
 448  */
 449
 450 int sysdev_resume(void)
 451 {
 452         struct sysdev_class * cls;
 453
 454         pr_debug("Resuming System Devices\n");
 455
 456         list_for_each_entry(cls, &system_kset->list, kset.kobj.entry) {
 457                 struct sys_device * sysdev;
 458
 459                 pr_debug("Resuming type '%s':\n",
 460                          kobject_name(&cls->kset.kobj));
 461
 462                 list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 463                         pr_debug(" %s\n", kobject_name(&sysdev->kobj));
 464
 465                         __sysdev_resume(sysdev);
 466                 }
 467         }
 468         return 0;
 469 }
 470
 471
 472 int __init system_bus_init(void)
 473 {
 474         system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
 475         if (!system_kset)
 476                 return -ENOMEM;
 477         return 0;
 478 }
 479
 480 EXPORT_SYMBOL_GPL(sysdev_register);
 481 EXPORT_SYMBOL_GPL(sysdev_unregister);
 482
 483 #define to_ext_attr(x) container_of(x, struct sysdev_ext_attribute, attr)
 484
 485 ssize_t sysdev_store_ulong(struct sys_device *sysdev,
 486                            struct sysdev_attribute *attr,
 487                            const char *buf, size_t size)
 488 {
 489         struct sysdev_ext_attribute *ea = to_ext_attr(attr);
 490         char *end;
 491         unsigned long new = simple_strtoul(buf, &end, 0);
 492         if (end == buf)
 493                 return -EINVAL;
 494         *(unsigned long *)(ea->var) = new;
 495         return end - buf;
 496 }
 497 EXPORT_SYMBOL_GPL(sysdev_store_ulong);
 498
 499 ssize_t sysdev_show_ulong(struct sys_device *sysdev,
 500                           struct sysdev_attribute *attr,
 501                           char *buf)
 502 {
 503         struct sysdev_ext_attribute *ea = to_ext_attr(attr);
 504         return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
 505 }
 506 EXPORT_SYMBOL_GPL(sysdev_show_ulong);
 507
 508 ssize_t sysdev_store_int(struct sys_device *sysdev,
 509                            struct sysdev_attribute *attr,
 510                            const char *buf, size_t size)
 511 {
 512         struct sysdev_ext_attribute *ea = to_ext_attr(attr);
 513         char *end;
 514         long new = simple_strtol(buf, &end, 0);
 515         if (end == buf || new > INT_MAX || new < INT_MIN)
 516                 return -EINVAL;
 517         *(int *)(ea->var) = new;
 518         return end - buf;
 519 }
 520 EXPORT_SYMBOL_GPL(sysdev_store_int);
 521
 522 ssize_t sysdev_show_int(struct sys_device *sysdev,
 523                           struct sysdev_attribute *attr,
 524                           char *buf)
 525 {
 526         struct sysdev_ext_attribute *ea = to_ext_attr(attr);
 527         return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
 528 }
 529 EXPORT_SYMBOL_GPL(sysdev_show_int);
 530