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/string.h>
  21 #include <linux/pm.h>
  22 #include <linux/device.h>
  23 #include <linux/mutex.h>
  24 #include <linux/interrupt.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 const 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, class_attr, 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, class_attr, buffer, count);
 103         return -EIO;
 104 }
 105
 106 static const 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         int retval;
 134
 135         pr_debug("Registering sysdev class '%s'\n", cls->name);
 136
 137         INIT_LIST_HEAD(&cls->drivers);
 138         memset(&cls->kset.kobj, 0x00, sizeof(struct kobject));
 139         cls->kset.kobj.parent = &system_kset->kobj;
 140         cls->kset.kobj.ktype = &ktype_sysdev_class;
 141         cls->kset.kobj.kset = system_kset;
 142
 143         retval = kobject_set_name(&cls->kset.kobj, "%s", cls->name);
 144         if (retval)
 145                 return retval;
 146
 147         retval = kset_register(&cls->kset);
 148         if (!retval && cls->attrs)
 149                 retval = sysfs_create_files(&cls->kset.kobj,
 150                                             (const struct attribute **)cls->attrs);
 151         return retval;
 152 }
 153
 154 void sysdev_class_unregister(struct sysdev_class *cls)
 155 {
 156         pr_debug("Unregistering sysdev class '%s'\n",
 157                  kobject_name(&cls->kset.kobj));
 158         if (cls->attrs)
 159                 sysfs_remove_files(&cls->kset.kobj,
 160                                    (const struct attribute **)cls->attrs);
 161         kset_unregister(&cls->kset);
 162 }
 163
 164 EXPORT_SYMBOL_GPL(sysdev_class_register);
 165 EXPORT_SYMBOL_GPL(sysdev_class_unregister);
 166
 167 static DEFINE_MUTEX(sysdev_drivers_lock);
 168
 169 /*
 170  * @dev != NULL means that we're unwinding because some drv->add()
 171  * failed for some reason. You need to grab sysdev_drivers_lock before
 172  * calling this.
 173  */
 174 static void __sysdev_driver_remove(struct sysdev_class *cls,
 175                                    struct sysdev_driver *drv,
 176                                    struct sys_device *from_dev)
 177 {
 178         struct sys_device *dev = from_dev;
 179
 180         list_del_init(&drv->entry);
 181         if (!cls)
 182                 return;
 183
 184         if (!drv->remove)
 185                 goto kset_put;
 186
 187         if (dev)
 188                 list_for_each_entry_continue_reverse(dev, &cls->kset.list,
 189                                                      kobj.entry)
 190                         drv->remove(dev);
 191         else
 192                 list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 193                         drv->remove(dev);
 194
 195 kset_put:
 196         kset_put(&cls->kset);
 197 }
 198
 199 /**
 200  *      sysdev_driver_register - Register auxiliary driver
 201  *      @cls:   Device class driver belongs to.
 202  *      @drv:   Driver.
 203  *
 204  *      @drv is inserted into @cls->drivers to be
 205  *      called on each operation on devices of that class. The refcount
 206  *      of @cls is incremented.
 207  */
 208 int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)
 209 {
 210         struct sys_device *dev = NULL;
 211         int err = 0;
 212
 213         if (!cls) {
 214                 WARN(1, KERN_WARNING "sysdev: invalid class passed to %s!\n",
 215                         __func__);
 216                 return -EINVAL;
 217         }
 218
 219         /* Check whether this driver has already been added to a class. */
 220         if (drv->entry.next && !list_empty(&drv->entry))
 221                 WARN(1, KERN_WARNING "sysdev: class %s: driver (%p) has already"
 222                         " been registered to a class, something is wrong, but "
 223                         "will forge on!\n", cls->name, drv);
 224
 225         mutex_lock(&sysdev_drivers_lock);
 226         if (cls && kset_get(&cls->kset)) {
 227                 list_add_tail(&drv->entry, &cls->drivers);
 228
 229                 /* If devices of this class already exist, tell the driver */
 230                 if (drv->add) {
 231                         list_for_each_entry(dev, &cls->kset.list, kobj.entry) {
 232                                 err = drv->add(dev);
 233                                 if (err)
 234                                         goto unwind;
 235                         }
 236                 }
 237         } else {
 238                 err = -EINVAL;
 239                 WARN(1, KERN_ERR "%s: invalid device class\n", __func__);
 240         }
 241
 242         goto unlock;
 243
 244 unwind:
 245         __sysdev_driver_remove(cls, drv, dev);
 246
 247 unlock:
 248         mutex_unlock(&sysdev_drivers_lock);
 249         return err;
 250 }
 251
 252 /**
 253  *      sysdev_driver_unregister - Remove an auxiliary driver.
 254  *      @cls:   Class driver belongs to.
 255  *      @drv:   Driver.
 256  */
 257 void sysdev_driver_unregister(struct sysdev_class *cls,
 258                               struct sysdev_driver *drv)
 259 {
 260         mutex_lock(&sysdev_drivers_lock);
 261         __sysdev_driver_remove(cls, drv, NULL);
 262         mutex_unlock(&sysdev_drivers_lock);
 263 }
 264 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 265 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
 266
 267 /**
 268  *      sysdev_register - add a system device to the tree
 269  *      @sysdev:        device in question
 270  *
 271  */
 272 int sysdev_register(struct sys_device *sysdev)
 273 {
 274         int error;
 275         struct sysdev_class *cls = sysdev->cls;
 276
 277         if (!cls)
 278                 return -EINVAL;
 279
 280         pr_debug("Registering sys device of class '%s'\n",
 281                  kobject_name(&cls->kset.kobj));
 282
 283         /* initialize the kobject to 0, in case it had previously been used */
 284         memset(&sysdev->kobj, 0x00, sizeof(struct kobject));
 285
 286         /* Make sure the kset is set */
 287         sysdev->kobj.kset = &cls->kset;
 288
 289         /* Register the object */
 290         error = kobject_init_and_add(&sysdev->kobj, &ktype_sysdev, NULL,
 291                                      "%s%d", kobject_name(&cls->kset.kobj),
 292                                      sysdev->id);
 293
 294         if (!error) {
 295                 struct sysdev_driver *drv;
 296
 297                 pr_debug("Registering sys device '%s'\n",
 298                          kobject_name(&sysdev->kobj));
 299
 300                 mutex_lock(&sysdev_drivers_lock);
 301                 /* Generic notification is implicit, because it's that
 302                  * code that should have called us.
 303                  */
 304
 305                 /* Notify class auxiliary drivers */
 306                 list_for_each_entry(drv, &cls->drivers, entry) {
 307                         if (drv->add)
 308                                 drv->add(sysdev);
 309                 }
 310                 mutex_unlock(&sysdev_drivers_lock);
 311                 kobject_uevent(&sysdev->kobj, KOBJ_ADD);
 312         }
 313
 314         return error;
 315 }
 316
 317 void sysdev_unregister(struct sys_device *sysdev)
 318 {
 319         struct sysdev_driver *drv;
 320
 321         mutex_lock(&sysdev_drivers_lock);
 322         list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 323                 if (drv->remove)
 324                         drv->remove(sysdev);
 325         }
 326         mutex_unlock(&sysdev_drivers_lock);
 327
 328         kobject_put(&sysdev->kobj);
 329 }
 330
 331 EXPORT_SYMBOL_GPL(sysdev_register);
 332 EXPORT_SYMBOL_GPL(sysdev_unregister);
 333
 334 int __init system_bus_init(void)
 335 {
 336         system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
 337         if (!system_kset)
 338                 return -ENOMEM;
 339         return 0;
 340 }
 341
 342 #define to_ext_attr(x) container_of(x, struct sysdev_ext_attribute, attr)
 343
 344 ssize_t sysdev_store_ulong(struct sys_device *sysdev,
 345                            struct sysdev_attribute *attr,
 346                            const char *buf, size_t size)
 347 {
 348         struct sysdev_ext_attribute *ea = to_ext_attr(attr);
 349         char *end;
 350         unsigned long new = simple_strtoul(buf, &end, 0);
 351         if (end == buf)
 352                 return -EINVAL;
 353         *(unsigned long *)(ea->var) = new;
 354         /* Always return full write size even if we didn't consume all */
 355         return size;
 356 }
 357 EXPORT_SYMBOL_GPL(sysdev_store_ulong);
 358
 359 ssize_t sysdev_show_ulong(struct sys_device *sysdev,
 360                           struct sysdev_attribute *attr,
 361                           char *buf)
 362 {
 363         struct sysdev_ext_attribute *ea = to_ext_attr(attr);
 364         return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
 365 }
 366 EXPORT_SYMBOL_GPL(sysdev_show_ulong);
 367
 368 ssize_t sysdev_store_int(struct sys_device *sysdev,
 369                            struct sysdev_attribute *attr,
 370                            const char *buf, size_t size)
 371 {
 372         struct sysdev_ext_attribute *ea = to_ext_attr(attr);
 373         char *end;
 374         long new = simple_strtol(buf, &end, 0);
 375         if (end == buf || new > INT_MAX || new < INT_MIN)
 376                 return -EINVAL;
 377         *(int *)(ea->var) = new;
 378         /* Always return full write size even if we didn't consume all */
 379         return size;
 380 }
 381 EXPORT_SYMBOL_GPL(sysdev_store_int);
 382
 383 ssize_t sysdev_show_int(struct sys_device *sysdev,
 384                           struct sysdev_attribute *attr,
 385                           char *buf)
 386 {
 387         struct sysdev_ext_attribute *ea = to_ext_attr(attr);
 388         return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
 389 }
 390 EXPORT_SYMBOL_GPL(sysdev_show_int);
 391