1 /* 2 * drivers/base/core.c - core driver model code (device registration, etc) 3 * 4 * Copyright (c) 2002-3 Patrick Mochel 5 * Copyright (c) 2002-3 Open Source Development Labs 6 * 7 * This file is released under the GPLv2 8 * 9 */ 10 11 #include <linux/config.h> 12 #include <linux/device.h> 13 #include <linux/err.h> 14 #include <linux/init.h> 15 #include <linux/module.h> 16 #include <linux/slab.h> 17 #include <linux/string.h> 18 19 #include <asm/semaphore.h> 20 21 #include "base.h" 22 #include "power/power.h" 23 24 int (*platform_notify)(struct device * dev) = NULL; 25 int (*platform_notify_remove)(struct device * dev) = NULL; 26 27 /* 28 * sysfs bindings for devices. 29 */ 30 31 #define to_dev(obj) container_of(obj, struct device, kobj) 32 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) 33 34 static ssize_t 35 dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) 36 { 37 struct device_attribute * dev_attr = to_dev_attr(attr); 38 struct device * dev = to_dev(kobj); 39 ssize_t ret = -EIO; 40 41 if (dev_attr->show) 42 ret = dev_attr->show(dev, dev_attr, buf); 43 return ret; 44 } 45 46 static ssize_t 47 dev_attr_store(struct kobject * kobj, struct attribute * attr, 48 const char * buf, size_t count) 49 { 50 struct device_attribute * dev_attr = to_dev_attr(attr); 51 struct device * dev = to_dev(kobj); 52 ssize_t ret = -EIO; 53 54 if (dev_attr->store) 55 ret = dev_attr->store(dev, dev_attr, buf, count); 56 return ret; 57 } 58 59 static struct sysfs_ops dev_sysfs_ops = { 60 .show = dev_attr_show, 61 .store = dev_attr_store, 62 }; 63 64 65 /** 66 * device_release - free device structure. 67 * @kobj: device's kobject. 68 * 69 * This is called once the reference count for the object 70 * reaches 0. We forward the call to the device's release 71 * method, which should handle actually freeing the structure. 72 */ 73 static void device_release(struct kobject * kobj) 74 { 75 struct device * dev = to_dev(kobj); 76 77 if (dev->release) 78 dev->release(dev); 79 else { 80 printk(KERN_ERR "Device '%s' does not have a release() function, " 81 "it is broken and must be fixed.\n", 82 dev->bus_id); 83 WARN_ON(1); 84 } 85 } 86 87 static struct kobj_type ktype_device = { 88 .release = device_release, 89 .sysfs_ops = &dev_sysfs_ops, 90 }; 91 92 93 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj) 94 { 95 struct kobj_type *ktype = get_ktype(kobj); 96 97 if (ktype == &ktype_device) { 98 struct device *dev = to_dev(kobj); 99 if (dev->bus) 100 return 1; 101 } 102 return 0; 103 } 104 105 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj) 106 { 107 struct device *dev = to_dev(kobj); 108 109 return dev->bus->name; 110 } 111 112 static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp, 113 int num_envp, char *buffer, int buffer_size) 114 { 115 struct device *dev = to_dev(kobj); 116 int i = 0; 117 int length = 0; 118 int retval = 0; 119 120 /* add bus name of physical device */ 121 if (dev->bus) 122 add_uevent_var(envp, num_envp, &i, 123 buffer, buffer_size, &length, 124 "PHYSDEVBUS=%s", dev->bus->name); 125 126 /* add driver name of physical device */ 127 if (dev->driver) 128 add_uevent_var(envp, num_envp, &i, 129 buffer, buffer_size, &length, 130 "PHYSDEVDRIVER=%s", dev->driver->name); 131 132 /* terminate, set to next free slot, shrink available space */ 133 envp[i] = NULL; 134 envp = &envp[i]; 135 num_envp -= i; 136 buffer = &buffer[length]; 137 buffer_size -= length; 138 139 if (dev->bus && dev->bus->uevent) { 140 /* have the bus specific function add its stuff */ 141 retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size); 142 if (retval) { 143 pr_debug ("%s - uevent() returned %d\n", 144 __FUNCTION__, retval); 145 } 146 } 147 148 return retval; 149 } 150 151 static struct kset_uevent_ops device_uevent_ops = { 152 .filter = dev_uevent_filter, 153 .name = dev_uevent_name, 154 .uevent = dev_uevent, 155 }; 156 157 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr, 158 const char *buf, size_t count) 159 { 160 kobject_uevent(&dev->kobj, KOBJ_ADD); 161 return count; 162 } 163 164 /* 165 * devices_subsys - structure to be registered with kobject core. 166 */ 167 168 decl_subsys(devices, &ktype_device, &device_uevent_ops); 169 170 171 /** 172 * device_create_file - create sysfs attribute file for device. 173 * @dev: device. 174 * @attr: device attribute descriptor. 175 */ 176 177 int device_create_file(struct device * dev, struct device_attribute * attr) 178 { 179 int error = 0; 180 if (get_device(dev)) { 181 error = sysfs_create_file(&dev->kobj, &attr->attr); 182 put_device(dev); 183 } 184 return error; 185 } 186 187 /** 188 * device_remove_file - remove sysfs attribute file. 189 * @dev: device. 190 * @attr: device attribute descriptor. 191 */ 192 193 void device_remove_file(struct device * dev, struct device_attribute * attr) 194 { 195 if (get_device(dev)) { 196 sysfs_remove_file(&dev->kobj, &attr->attr); 197 put_device(dev); 198 } 199 } 200 201 static void klist_children_get(struct klist_node *n) 202 { 203 struct device *dev = container_of(n, struct device, knode_parent); 204 205 get_device(dev); 206 } 207 208 static void klist_children_put(struct klist_node *n) 209 { 210 struct device *dev = container_of(n, struct device, knode_parent); 211 212 put_device(dev); 213 } 214 215 216 /** 217 * device_initialize - init device structure. 218 * @dev: device. 219 * 220 * This prepares the device for use by other layers, 221 * including adding it to the device hierarchy. 222 * It is the first half of device_register(), if called by 223 * that, though it can also be called separately, so one 224 * may use @dev's fields (e.g. the refcount). 225 */ 226 227 void device_initialize(struct device *dev) 228 { 229 kobj_set_kset_s(dev, devices_subsys); 230 kobject_init(&dev->kobj); 231 klist_init(&dev->klist_children, klist_children_get, 232 klist_children_put); 233 INIT_LIST_HEAD(&dev->dma_pools); 234 init_MUTEX(&dev->sem); 235 device_init_wakeup(dev, 0); 236 } 237 238 /** 239 * device_add - add device to device hierarchy. 240 * @dev: device. 241 * 242 * This is part 2 of device_register(), though may be called 243 * separately _iff_ device_initialize() has been called separately. 244 * 245 * This adds it to the kobject hierarchy via kobject_add(), adds it 246 * to the global and sibling lists for the device, then 247 * adds it to the other relevant subsystems of the driver model. 248 */ 249 int device_add(struct device *dev) 250 { 251 struct device *parent = NULL; 252 int error = -EINVAL; 253 254 dev = get_device(dev); 255 if (!dev || !strlen(dev->bus_id)) 256 goto Error; 257 258 parent = get_device(dev->parent); 259 260 pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id); 261 262 /* first, register with generic layer. */ 263 kobject_set_name(&dev->kobj, "%s", dev->bus_id); 264 if (parent) 265 dev->kobj.parent = &parent->kobj; 266 267 if ((error = kobject_add(&dev->kobj))) 268 goto Error; 269 270 dev->uevent_attr.attr.name = "uevent"; 271 dev->uevent_attr.attr.mode = S_IWUSR; 272 if (dev->driver) 273 dev->uevent_attr.attr.owner = dev->driver->owner; 274 dev->uevent_attr.store = store_uevent; 275 device_create_file(dev, &dev->uevent_attr); 276 277 kobject_uevent(&dev->kobj, KOBJ_ADD); 278 if ((error = device_pm_add(dev))) 279 goto PMError; 280 if ((error = bus_add_device(dev))) 281 goto BusError; 282 if (parent) 283 klist_add_tail(&dev->knode_parent, &parent->klist_children); 284 285 /* notify platform of device entry */ 286 if (platform_notify) 287 platform_notify(dev); 288 Done: 289 put_device(dev); 290 return error; 291 BusError: 292 device_pm_remove(dev); 293 PMError: 294 kobject_uevent(&dev->kobj, KOBJ_REMOVE); 295 kobject_del(&dev->kobj); 296 Error: 297 if (parent) 298 put_device(parent); 299 goto Done; 300 } 301 302 303 /** 304 * device_register - register a device with the system. 305 * @dev: pointer to the device structure 306 * 307 * This happens in two clean steps - initialize the device 308 * and add it to the system. The two steps can be called 309 * separately, but this is the easiest and most common. 310 * I.e. you should only call the two helpers separately if 311 * have a clearly defined need to use and refcount the device 312 * before it is added to the hierarchy. 313 */ 314 315 int device_register(struct device *dev) 316 { 317 device_initialize(dev); 318 return device_add(dev); 319 } 320 321 322 /** 323 * get_device - increment reference count for device. 324 * @dev: device. 325 * 326 * This simply forwards the call to kobject_get(), though 327 * we do take care to provide for the case that we get a NULL 328 * pointer passed in. 329 */ 330 331 struct device * get_device(struct device * dev) 332 { 333 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL; 334 } 335 336 337 /** 338 * put_device - decrement reference count. 339 * @dev: device in question. 340 */ 341 void put_device(struct device * dev) 342 { 343 if (dev) 344 kobject_put(&dev->kobj); 345 } 346 347 348 /** 349 * device_del - delete device from system. 350 * @dev: device. 351 * 352 * This is the first part of the device unregistration 353 * sequence. This removes the device from the lists we control 354 * from here, has it removed from the other driver model 355 * subsystems it was added to in device_add(), and removes it 356 * from the kobject hierarchy. 357 * 358 * NOTE: this should be called manually _iff_ device_add() was 359 * also called manually. 360 */ 361 362 void device_del(struct device * dev) 363 { 364 struct device * parent = dev->parent; 365 366 if (parent) 367 klist_del(&dev->knode_parent); 368 device_remove_file(dev, &dev->uevent_attr); 369 370 /* Notify the platform of the removal, in case they 371 * need to do anything... 372 */ 373 if (platform_notify_remove) 374 platform_notify_remove(dev); 375 bus_remove_device(dev); 376 device_pm_remove(dev); 377 kobject_uevent(&dev->kobj, KOBJ_REMOVE); 378 kobject_del(&dev->kobj); 379 if (parent) 380 put_device(parent); 381 } 382 383 /** 384 * device_unregister - unregister device from system. 385 * @dev: device going away. 386 * 387 * We do this in two parts, like we do device_register(). First, 388 * we remove it from all the subsystems with device_del(), then 389 * we decrement the reference count via put_device(). If that 390 * is the final reference count, the device will be cleaned up 391 * via device_release() above. Otherwise, the structure will 392 * stick around until the final reference to the device is dropped. 393 */ 394 void device_unregister(struct device * dev) 395 { 396 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id); 397 device_del(dev); 398 put_device(dev); 399 } 400 401 402 static struct device * next_device(struct klist_iter * i) 403 { 404 struct klist_node * n = klist_next(i); 405 return n ? container_of(n, struct device, knode_parent) : NULL; 406 } 407 408 /** 409 * device_for_each_child - device child iterator. 410 * @parent: parent struct device. 411 * @data: data for the callback. 412 * @fn: function to be called for each device. 413 * 414 * Iterate over @parent's child devices, and call @fn for each, 415 * passing it @data. 416 * 417 * We check the return of @fn each time. If it returns anything 418 * other than 0, we break out and return that value. 419 */ 420 int device_for_each_child(struct device * parent, void * data, 421 int (*fn)(struct device *, void *)) 422 { 423 struct klist_iter i; 424 struct device * child; 425 int error = 0; 426 427 klist_iter_init(&parent->klist_children, &i); 428 while ((child = next_device(&i)) && !error) 429 error = fn(child, data); 430 klist_iter_exit(&i); 431 return error; 432 } 433 434 int __init devices_init(void) 435 { 436 return subsystem_register(&devices_subsys); 437 } 438 439 EXPORT_SYMBOL_GPL(device_for_each_child); 440 441 EXPORT_SYMBOL_GPL(device_initialize); 442 EXPORT_SYMBOL_GPL(device_add); 443 EXPORT_SYMBOL_GPL(device_register); 444 445 EXPORT_SYMBOL_GPL(device_del); 446 EXPORT_SYMBOL_GPL(device_unregister); 447 EXPORT_SYMBOL_GPL(get_device); 448 EXPORT_SYMBOL_GPL(put_device); 449 450 EXPORT_SYMBOL_GPL(device_create_file); 451 EXPORT_SYMBOL_GPL(device_remove_file); 452