xref: /linux/drivers/acpi/scan.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2  * scan.c - support for transforming the ACPI namespace into individual objects
3  */
4 
5 #include <linux/module.h>
6 #include <linux/init.h>
7 #include <linux/acpi.h>
8 
9 #include <acpi/acpi_drivers.h>
10 #include <acpi/acinterp.h>	/* for acpi_ex_eisa_id_to_string() */
11 
12 #define _COMPONENT		ACPI_BUS_COMPONENT
13 ACPI_MODULE_NAME("scan")
14 #define STRUCT_TO_INT(s)	(*((int*)&s))
15 extern struct acpi_device *acpi_root;
16 
17 #define ACPI_BUS_CLASS			"system_bus"
18 #define ACPI_BUS_HID			"ACPI_BUS"
19 #define ACPI_BUS_DRIVER_NAME		"ACPI Bus Driver"
20 #define ACPI_BUS_DEVICE_NAME		"System Bus"
21 
22 static LIST_HEAD(acpi_device_list);
23 DEFINE_SPINLOCK(acpi_device_lock);
24 LIST_HEAD(acpi_wakeup_device_list);
25 
26 
27 static void acpi_device_release(struct kobject *kobj)
28 {
29 	struct acpi_device *dev = container_of(kobj, struct acpi_device, kobj);
30 	kfree(dev->pnp.cid_list);
31 	kfree(dev);
32 }
33 
34 struct acpi_device_attribute {
35 	struct attribute attr;
36 	 ssize_t(*show) (struct acpi_device *, char *);
37 	 ssize_t(*store) (struct acpi_device *, const char *, size_t);
38 };
39 
40 typedef void acpi_device_sysfs_files(struct kobject *,
41 				     const struct attribute *);
42 
43 static void setup_sys_fs_device_files(struct acpi_device *dev,
44 				      acpi_device_sysfs_files * func);
45 
46 #define create_sysfs_device_files(dev)	\
47 	setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_create_file)
48 #define remove_sysfs_device_files(dev)	\
49 	setup_sys_fs_device_files(dev, (acpi_device_sysfs_files *)&sysfs_remove_file)
50 
51 #define to_acpi_device(n) container_of(n, struct acpi_device, kobj)
52 #define to_handle_attr(n) container_of(n, struct acpi_device_attribute, attr);
53 
54 static ssize_t acpi_device_attr_show(struct kobject *kobj,
55 				     struct attribute *attr, char *buf)
56 {
57 	struct acpi_device *device = to_acpi_device(kobj);
58 	struct acpi_device_attribute *attribute = to_handle_attr(attr);
59 	return attribute->show ? attribute->show(device, buf) : -EIO;
60 }
61 static ssize_t acpi_device_attr_store(struct kobject *kobj,
62 				      struct attribute *attr, const char *buf,
63 				      size_t len)
64 {
65 	struct acpi_device *device = to_acpi_device(kobj);
66 	struct acpi_device_attribute *attribute = to_handle_attr(attr);
67 	return attribute->store ? attribute->store(device, buf, len) : -EIO;
68 }
69 
70 static struct sysfs_ops acpi_device_sysfs_ops = {
71 	.show = acpi_device_attr_show,
72 	.store = acpi_device_attr_store,
73 };
74 
75 static struct kobj_type ktype_acpi_ns = {
76 	.sysfs_ops = &acpi_device_sysfs_ops,
77 	.release = acpi_device_release,
78 };
79 
80 static int namespace_uevent(struct kset *kset, struct kobject *kobj,
81 			     char **envp, int num_envp, char *buffer,
82 			     int buffer_size)
83 {
84 	struct acpi_device *dev = to_acpi_device(kobj);
85 	int i = 0;
86 	int len = 0;
87 
88 	if (!dev->driver)
89 		return 0;
90 
91 	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
92 			   "PHYSDEVDRIVER=%s", dev->driver->name))
93 		return -ENOMEM;
94 
95 	envp[i] = NULL;
96 
97 	return 0;
98 }
99 
100 static struct kset_uevent_ops namespace_uevent_ops = {
101 	.uevent = &namespace_uevent,
102 };
103 
104 static struct kset acpi_namespace_kset = {
105 	.kobj = {
106 		 .name = "namespace",
107 		 },
108 	.subsys = &acpi_subsys,
109 	.ktype = &ktype_acpi_ns,
110 	.uevent_ops = &namespace_uevent_ops,
111 };
112 
113 static void acpi_device_register(struct acpi_device *device,
114 				 struct acpi_device *parent)
115 {
116 	/*
117 	 * Linkage
118 	 * -------
119 	 * Link this device to its parent and siblings.
120 	 */
121 	INIT_LIST_HEAD(&device->children);
122 	INIT_LIST_HEAD(&device->node);
123 	INIT_LIST_HEAD(&device->g_list);
124 	INIT_LIST_HEAD(&device->wakeup_list);
125 
126 	spin_lock(&acpi_device_lock);
127 	if (device->parent) {
128 		list_add_tail(&device->node, &device->parent->children);
129 		list_add_tail(&device->g_list, &device->parent->g_list);
130 	} else
131 		list_add_tail(&device->g_list, &acpi_device_list);
132 	if (device->wakeup.flags.valid)
133 		list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
134 	spin_unlock(&acpi_device_lock);
135 
136 	strlcpy(device->kobj.name, device->pnp.bus_id, KOBJ_NAME_LEN);
137 	if (parent)
138 		device->kobj.parent = &parent->kobj;
139 	device->kobj.ktype = &ktype_acpi_ns;
140 	device->kobj.kset = &acpi_namespace_kset;
141 	kobject_register(&device->kobj);
142 	create_sysfs_device_files(device);
143 }
144 
145 static int acpi_device_unregister(struct acpi_device *device, int type)
146 {
147 	spin_lock(&acpi_device_lock);
148 	if (device->parent) {
149 		list_del(&device->node);
150 		list_del(&device->g_list);
151 	} else
152 		list_del(&device->g_list);
153 
154 	list_del(&device->wakeup_list);
155 
156 	spin_unlock(&acpi_device_lock);
157 
158 	acpi_detach_data(device->handle, acpi_bus_data_handler);
159 	remove_sysfs_device_files(device);
160 	kobject_unregister(&device->kobj);
161 	return 0;
162 }
163 
164 void acpi_bus_data_handler(acpi_handle handle, u32 function, void *context)
165 {
166 	ACPI_FUNCTION_TRACE("acpi_bus_data_handler");
167 
168 	/* TBD */
169 
170 	return_VOID;
171 }
172 
173 static int acpi_bus_get_power_flags(struct acpi_device *device)
174 {
175 	acpi_status status = 0;
176 	acpi_handle handle = NULL;
177 	u32 i = 0;
178 
179 	ACPI_FUNCTION_TRACE("acpi_bus_get_power_flags");
180 
181 	/*
182 	 * Power Management Flags
183 	 */
184 	status = acpi_get_handle(device->handle, "_PSC", &handle);
185 	if (ACPI_SUCCESS(status))
186 		device->power.flags.explicit_get = 1;
187 	status = acpi_get_handle(device->handle, "_IRC", &handle);
188 	if (ACPI_SUCCESS(status))
189 		device->power.flags.inrush_current = 1;
190 
191 	/*
192 	 * Enumerate supported power management states
193 	 */
194 	for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
195 		struct acpi_device_power_state *ps = &device->power.states[i];
196 		char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };
197 
198 		/* Evaluate "_PRx" to se if power resources are referenced */
199 		acpi_evaluate_reference(device->handle, object_name, NULL,
200 					&ps->resources);
201 		if (ps->resources.count) {
202 			device->power.flags.power_resources = 1;
203 			ps->flags.valid = 1;
204 		}
205 
206 		/* Evaluate "_PSx" to see if we can do explicit sets */
207 		object_name[2] = 'S';
208 		status = acpi_get_handle(device->handle, object_name, &handle);
209 		if (ACPI_SUCCESS(status)) {
210 			ps->flags.explicit_set = 1;
211 			ps->flags.valid = 1;
212 		}
213 
214 		/* State is valid if we have some power control */
215 		if (ps->resources.count || ps->flags.explicit_set)
216 			ps->flags.valid = 1;
217 
218 		ps->power = -1;	/* Unknown - driver assigned */
219 		ps->latency = -1;	/* Unknown - driver assigned */
220 	}
221 
222 	/* Set defaults for D0 and D3 states (always valid) */
223 	device->power.states[ACPI_STATE_D0].flags.valid = 1;
224 	device->power.states[ACPI_STATE_D0].power = 100;
225 	device->power.states[ACPI_STATE_D3].flags.valid = 1;
226 	device->power.states[ACPI_STATE_D3].power = 0;
227 
228 	/* TBD: System wake support and resource requirements. */
229 
230 	device->power.state = ACPI_STATE_UNKNOWN;
231 
232 	return_VALUE(0);
233 }
234 
235 int acpi_match_ids(struct acpi_device *device, char *ids)
236 {
237 	int error = 0;
238 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
239 
240 	if (device->flags.hardware_id)
241 		if (strstr(ids, device->pnp.hardware_id))
242 			goto Done;
243 
244 	if (device->flags.compatible_ids) {
245 		struct acpi_compatible_id_list *cid_list = device->pnp.cid_list;
246 		int i;
247 
248 		/* compare multiple _CID entries against driver ids */
249 		for (i = 0; i < cid_list->count; i++) {
250 			if (strstr(ids, cid_list->id[i].value))
251 				goto Done;
252 		}
253 	}
254 	error = -ENOENT;
255 
256       Done:
257 	if (buffer.pointer)
258 		acpi_os_free(buffer.pointer);
259 	return error;
260 }
261 
262 static acpi_status
263 acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
264 					     union acpi_object *package)
265 {
266 	int i = 0;
267 	union acpi_object *element = NULL;
268 
269 	if (!device || !package || (package->package.count < 2))
270 		return AE_BAD_PARAMETER;
271 
272 	element = &(package->package.elements[0]);
273 	if (!element)
274 		return AE_BAD_PARAMETER;
275 	if (element->type == ACPI_TYPE_PACKAGE) {
276 		if ((element->package.count < 2) ||
277 		    (element->package.elements[0].type !=
278 		     ACPI_TYPE_LOCAL_REFERENCE)
279 		    || (element->package.elements[1].type != ACPI_TYPE_INTEGER))
280 			return AE_BAD_DATA;
281 		device->wakeup.gpe_device =
282 		    element->package.elements[0].reference.handle;
283 		device->wakeup.gpe_number =
284 		    (u32) element->package.elements[1].integer.value;
285 	} else if (element->type == ACPI_TYPE_INTEGER) {
286 		device->wakeup.gpe_number = element->integer.value;
287 	} else
288 		return AE_BAD_DATA;
289 
290 	element = &(package->package.elements[1]);
291 	if (element->type != ACPI_TYPE_INTEGER) {
292 		return AE_BAD_DATA;
293 	}
294 	device->wakeup.sleep_state = element->integer.value;
295 
296 	if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
297 		return AE_NO_MEMORY;
298 	}
299 	device->wakeup.resources.count = package->package.count - 2;
300 	for (i = 0; i < device->wakeup.resources.count; i++) {
301 		element = &(package->package.elements[i + 2]);
302 		if (element->type != ACPI_TYPE_ANY) {
303 			return AE_BAD_DATA;
304 		}
305 
306 		device->wakeup.resources.handles[i] = element->reference.handle;
307 	}
308 
309 	return AE_OK;
310 }
311 
312 static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
313 {
314 	acpi_status status = 0;
315 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
316 	union acpi_object *package = NULL;
317 
318 	ACPI_FUNCTION_TRACE("acpi_bus_get_wakeup_flags");
319 
320 	/* _PRW */
321 	status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
322 	if (ACPI_FAILURE(status)) {
323 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRW\n"));
324 		goto end;
325 	}
326 
327 	package = (union acpi_object *)buffer.pointer;
328 	status = acpi_bus_extract_wakeup_device_power_package(device, package);
329 	if (ACPI_FAILURE(status)) {
330 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
331 				  "Error extracting _PRW package\n"));
332 		goto end;
333 	}
334 
335 	acpi_os_free(buffer.pointer);
336 
337 	device->wakeup.flags.valid = 1;
338 	/* Power button, Lid switch always enable wakeup */
339 	if (!acpi_match_ids(device, "PNP0C0D,PNP0C0C,PNP0C0E"))
340 		device->wakeup.flags.run_wake = 1;
341 
342       end:
343 	if (ACPI_FAILURE(status))
344 		device->flags.wake_capable = 0;
345 	return_VALUE(0);
346 }
347 
348 /* --------------------------------------------------------------------------
349 		ACPI sysfs device file support
350    -------------------------------------------------------------------------- */
351 static ssize_t acpi_eject_store(struct acpi_device *device,
352 				const char *buf, size_t count);
353 
354 #define ACPI_DEVICE_ATTR(_name,_mode,_show,_store) \
355 static struct acpi_device_attribute acpi_device_attr_##_name = \
356 		__ATTR(_name, _mode, _show, _store)
357 
358 ACPI_DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
359 
360 /**
361  * setup_sys_fs_device_files - sets up the device files under device namespace
362  * @dev:	acpi_device object
363  * @func:	function pointer to create or destroy the device file
364  */
365 static void
366 setup_sys_fs_device_files(struct acpi_device *dev,
367 			  acpi_device_sysfs_files * func)
368 {
369 	acpi_status status;
370 	acpi_handle temp = NULL;
371 
372 	/*
373 	 * If device has _EJ0, 'eject' file is created that is used to trigger
374 	 * hot-removal function from userland.
375 	 */
376 	status = acpi_get_handle(dev->handle, "_EJ0", &temp);
377 	if (ACPI_SUCCESS(status))
378 		(*(func)) (&dev->kobj, &acpi_device_attr_eject.attr);
379 }
380 
381 static int acpi_eject_operation(acpi_handle handle, int lockable)
382 {
383 	struct acpi_object_list arg_list;
384 	union acpi_object arg;
385 	acpi_status status = AE_OK;
386 
387 	/*
388 	 * TBD: evaluate _PS3?
389 	 */
390 
391 	if (lockable) {
392 		arg_list.count = 1;
393 		arg_list.pointer = &arg;
394 		arg.type = ACPI_TYPE_INTEGER;
395 		arg.integer.value = 0;
396 		acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
397 	}
398 
399 	arg_list.count = 1;
400 	arg_list.pointer = &arg;
401 	arg.type = ACPI_TYPE_INTEGER;
402 	arg.integer.value = 1;
403 
404 	/*
405 	 * TBD: _EJD support.
406 	 */
407 
408 	status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
409 	if (ACPI_FAILURE(status)) {
410 		return (-ENODEV);
411 	}
412 
413 	return (0);
414 }
415 
416 static ssize_t
417 acpi_eject_store(struct acpi_device *device, const char *buf, size_t count)
418 {
419 	int result;
420 	int ret = count;
421 	int islockable;
422 	acpi_status status;
423 	acpi_handle handle;
424 	acpi_object_type type = 0;
425 
426 	if ((!count) || (buf[0] != '1')) {
427 		return -EINVAL;
428 	}
429 #ifndef FORCE_EJECT
430 	if (device->driver == NULL) {
431 		ret = -ENODEV;
432 		goto err;
433 	}
434 #endif
435 	status = acpi_get_type(device->handle, &type);
436 	if (ACPI_FAILURE(status) || (!device->flags.ejectable)) {
437 		ret = -ENODEV;
438 		goto err;
439 	}
440 
441 	islockable = device->flags.lockable;
442 	handle = device->handle;
443 
444 	if (type == ACPI_TYPE_PROCESSOR)
445 		result = acpi_bus_trim(device, 0);
446 	else
447 		result = acpi_bus_trim(device, 1);
448 
449 	if (!result)
450 		result = acpi_eject_operation(handle, islockable);
451 
452 	if (result) {
453 		ret = -EBUSY;
454 	}
455       err:
456 	return ret;
457 }
458 
459 /* --------------------------------------------------------------------------
460                               Performance Management
461    -------------------------------------------------------------------------- */
462 
463 static int acpi_bus_get_perf_flags(struct acpi_device *device)
464 {
465 	device->performance.state = ACPI_STATE_UNKNOWN;
466 	return 0;
467 }
468 
469 /* --------------------------------------------------------------------------
470                                  Driver Management
471    -------------------------------------------------------------------------- */
472 
473 static LIST_HEAD(acpi_bus_drivers);
474 static DECLARE_MUTEX(acpi_bus_drivers_lock);
475 
476 /**
477  * acpi_bus_match - match device IDs to driver's supported IDs
478  * @device: the device that we are trying to match to a driver
479  * @driver: driver whose device id table is being checked
480  *
481  * Checks the device's hardware (_HID) or compatible (_CID) ids to see if it
482  * matches the specified driver's criteria.
483  */
484 static int
485 acpi_bus_match(struct acpi_device *device, struct acpi_driver *driver)
486 {
487 	if (driver && driver->ops.match)
488 		return driver->ops.match(device, driver);
489 	return acpi_match_ids(device, driver->ids);
490 }
491 
492 /**
493  * acpi_bus_driver_init - add a device to a driver
494  * @device: the device to add and initialize
495  * @driver: driver for the device
496  *
497  * Used to initialize a device via its device driver.  Called whenever a
498  * driver is bound to a device.  Invokes the driver's add() and start() ops.
499  */
500 static int
501 acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
502 {
503 	int result = 0;
504 
505 	ACPI_FUNCTION_TRACE("acpi_bus_driver_init");
506 
507 	if (!device || !driver)
508 		return_VALUE(-EINVAL);
509 
510 	if (!driver->ops.add)
511 		return_VALUE(-ENOSYS);
512 
513 	result = driver->ops.add(device);
514 	if (result) {
515 		device->driver = NULL;
516 		acpi_driver_data(device) = NULL;
517 		return_VALUE(result);
518 	}
519 
520 	device->driver = driver;
521 
522 	/*
523 	 * TBD - Configuration Management: Assign resources to device based
524 	 * upon possible configuration and currently allocated resources.
525 	 */
526 
527 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
528 			  "Driver successfully bound to device\n"));
529 	return_VALUE(0);
530 }
531 
532 static int acpi_start_single_object(struct acpi_device *device)
533 {
534 	int result = 0;
535 	struct acpi_driver *driver;
536 
537 	ACPI_FUNCTION_TRACE("acpi_start_single_object");
538 
539 	if (!(driver = device->driver))
540 		return_VALUE(0);
541 
542 	if (driver->ops.start) {
543 		result = driver->ops.start(device);
544 		if (result && driver->ops.remove)
545 			driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
546 	}
547 
548 	return_VALUE(result);
549 }
550 
551 static int acpi_driver_attach(struct acpi_driver *drv)
552 {
553 	struct list_head *node, *next;
554 	int count = 0;
555 
556 	ACPI_FUNCTION_TRACE("acpi_driver_attach");
557 
558 	spin_lock(&acpi_device_lock);
559 	list_for_each_safe(node, next, &acpi_device_list) {
560 		struct acpi_device *dev =
561 		    container_of(node, struct acpi_device, g_list);
562 
563 		if (dev->driver || !dev->status.present)
564 			continue;
565 		spin_unlock(&acpi_device_lock);
566 
567 		if (!acpi_bus_match(dev, drv)) {
568 			if (!acpi_bus_driver_init(dev, drv)) {
569 				acpi_start_single_object(dev);
570 				atomic_inc(&drv->references);
571 				count++;
572 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
573 						  "Found driver [%s] for device [%s]\n",
574 						  drv->name, dev->pnp.bus_id));
575 			}
576 		}
577 		spin_lock(&acpi_device_lock);
578 	}
579 	spin_unlock(&acpi_device_lock);
580 	return_VALUE(count);
581 }
582 
583 static int acpi_driver_detach(struct acpi_driver *drv)
584 {
585 	struct list_head *node, *next;
586 
587 	ACPI_FUNCTION_TRACE("acpi_driver_detach");
588 
589 	spin_lock(&acpi_device_lock);
590 	list_for_each_safe(node, next, &acpi_device_list) {
591 		struct acpi_device *dev =
592 		    container_of(node, struct acpi_device, g_list);
593 
594 		if (dev->driver == drv) {
595 			spin_unlock(&acpi_device_lock);
596 			if (drv->ops.remove)
597 				drv->ops.remove(dev, ACPI_BUS_REMOVAL_NORMAL);
598 			spin_lock(&acpi_device_lock);
599 			dev->driver = NULL;
600 			dev->driver_data = NULL;
601 			atomic_dec(&drv->references);
602 		}
603 	}
604 	spin_unlock(&acpi_device_lock);
605 	return_VALUE(0);
606 }
607 
608 /**
609  * acpi_bus_register_driver - register a driver with the ACPI bus
610  * @driver: driver being registered
611  *
612  * Registers a driver with the ACPI bus.  Searches the namespace for all
613  * devices that match the driver's criteria and binds.  Returns the
614  * number of devices that were claimed by the driver, or a negative
615  * error status for failure.
616  */
617 int acpi_bus_register_driver(struct acpi_driver *driver)
618 {
619 	int count;
620 
621 	ACPI_FUNCTION_TRACE("acpi_bus_register_driver");
622 
623 	if (acpi_disabled)
624 		return_VALUE(-ENODEV);
625 
626 	if (!driver)
627 		return_VALUE(-EINVAL);
628 
629 	spin_lock(&acpi_device_lock);
630 	list_add_tail(&driver->node, &acpi_bus_drivers);
631 	spin_unlock(&acpi_device_lock);
632 	count = acpi_driver_attach(driver);
633 
634 	return_VALUE(count);
635 }
636 
637 EXPORT_SYMBOL(acpi_bus_register_driver);
638 
639 /**
640  * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
641  * @driver: driver to unregister
642  *
643  * Unregisters a driver with the ACPI bus.  Searches the namespace for all
644  * devices that match the driver's criteria and unbinds.
645  */
646 int acpi_bus_unregister_driver(struct acpi_driver *driver)
647 {
648 	int error = 0;
649 
650 	ACPI_FUNCTION_TRACE("acpi_bus_unregister_driver");
651 
652 	if (driver) {
653 		acpi_driver_detach(driver);
654 
655 		if (!atomic_read(&driver->references)) {
656 			spin_lock(&acpi_device_lock);
657 			list_del_init(&driver->node);
658 			spin_unlock(&acpi_device_lock);
659 		}
660 	} else
661 		error = -EINVAL;
662 	return_VALUE(error);
663 }
664 
665 EXPORT_SYMBOL(acpi_bus_unregister_driver);
666 
667 /**
668  * acpi_bus_find_driver - check if there is a driver installed for the device
669  * @device: device that we are trying to find a supporting driver for
670  *
671  * Parses the list of registered drivers looking for a driver applicable for
672  * the specified device.
673  */
674 static int acpi_bus_find_driver(struct acpi_device *device)
675 {
676 	int result = 0;
677 	struct list_head *node, *next;
678 
679 	ACPI_FUNCTION_TRACE("acpi_bus_find_driver");
680 
681 	spin_lock(&acpi_device_lock);
682 	list_for_each_safe(node, next, &acpi_bus_drivers) {
683 		struct acpi_driver *driver =
684 		    container_of(node, struct acpi_driver, node);
685 
686 		atomic_inc(&driver->references);
687 		spin_unlock(&acpi_device_lock);
688 		if (!acpi_bus_match(device, driver)) {
689 			result = acpi_bus_driver_init(device, driver);
690 			if (!result)
691 				goto Done;
692 		}
693 		atomic_dec(&driver->references);
694 		spin_lock(&acpi_device_lock);
695 	}
696 	spin_unlock(&acpi_device_lock);
697 
698       Done:
699 	return_VALUE(result);
700 }
701 
702 /* --------------------------------------------------------------------------
703                                  Device Enumeration
704    -------------------------------------------------------------------------- */
705 
706 static int acpi_bus_get_flags(struct acpi_device *device)
707 {
708 	acpi_status status = AE_OK;
709 	acpi_handle temp = NULL;
710 
711 	ACPI_FUNCTION_TRACE("acpi_bus_get_flags");
712 
713 	/* Presence of _STA indicates 'dynamic_status' */
714 	status = acpi_get_handle(device->handle, "_STA", &temp);
715 	if (ACPI_SUCCESS(status))
716 		device->flags.dynamic_status = 1;
717 
718 	/* Presence of _CID indicates 'compatible_ids' */
719 	status = acpi_get_handle(device->handle, "_CID", &temp);
720 	if (ACPI_SUCCESS(status))
721 		device->flags.compatible_ids = 1;
722 
723 	/* Presence of _RMV indicates 'removable' */
724 	status = acpi_get_handle(device->handle, "_RMV", &temp);
725 	if (ACPI_SUCCESS(status))
726 		device->flags.removable = 1;
727 
728 	/* Presence of _EJD|_EJ0 indicates 'ejectable' */
729 	status = acpi_get_handle(device->handle, "_EJD", &temp);
730 	if (ACPI_SUCCESS(status))
731 		device->flags.ejectable = 1;
732 	else {
733 		status = acpi_get_handle(device->handle, "_EJ0", &temp);
734 		if (ACPI_SUCCESS(status))
735 			device->flags.ejectable = 1;
736 	}
737 
738 	/* Presence of _LCK indicates 'lockable' */
739 	status = acpi_get_handle(device->handle, "_LCK", &temp);
740 	if (ACPI_SUCCESS(status))
741 		device->flags.lockable = 1;
742 
743 	/* Presence of _PS0|_PR0 indicates 'power manageable' */
744 	status = acpi_get_handle(device->handle, "_PS0", &temp);
745 	if (ACPI_FAILURE(status))
746 		status = acpi_get_handle(device->handle, "_PR0", &temp);
747 	if (ACPI_SUCCESS(status))
748 		device->flags.power_manageable = 1;
749 
750 	/* Presence of _PRW indicates wake capable */
751 	status = acpi_get_handle(device->handle, "_PRW", &temp);
752 	if (ACPI_SUCCESS(status))
753 		device->flags.wake_capable = 1;
754 
755 	/* TBD: Peformance management */
756 
757 	return_VALUE(0);
758 }
759 
760 static void acpi_device_get_busid(struct acpi_device *device,
761 				  acpi_handle handle, int type)
762 {
763 	char bus_id[5] = { '?', 0 };
764 	struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
765 	int i = 0;
766 
767 	/*
768 	 * Bus ID
769 	 * ------
770 	 * The device's Bus ID is simply the object name.
771 	 * TBD: Shouldn't this value be unique (within the ACPI namespace)?
772 	 */
773 	switch (type) {
774 	case ACPI_BUS_TYPE_SYSTEM:
775 		strcpy(device->pnp.bus_id, "ACPI");
776 		break;
777 	case ACPI_BUS_TYPE_POWER_BUTTON:
778 		strcpy(device->pnp.bus_id, "PWRF");
779 		break;
780 	case ACPI_BUS_TYPE_SLEEP_BUTTON:
781 		strcpy(device->pnp.bus_id, "SLPF");
782 		break;
783 	default:
784 		acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
785 		/* Clean up trailing underscores (if any) */
786 		for (i = 3; i > 1; i--) {
787 			if (bus_id[i] == '_')
788 				bus_id[i] = '\0';
789 			else
790 				break;
791 		}
792 		strcpy(device->pnp.bus_id, bus_id);
793 		break;
794 	}
795 }
796 
797 static void acpi_device_set_id(struct acpi_device *device,
798 			       struct acpi_device *parent, acpi_handle handle,
799 			       int type)
800 {
801 	struct acpi_device_info *info;
802 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
803 	char *hid = NULL;
804 	char *uid = NULL;
805 	struct acpi_compatible_id_list *cid_list = NULL;
806 	acpi_status status;
807 
808 	switch (type) {
809 	case ACPI_BUS_TYPE_DEVICE:
810 		status = acpi_get_object_info(handle, &buffer);
811 		if (ACPI_FAILURE(status)) {
812 			printk("%s: Error reading device info\n", __FUNCTION__);
813 			return;
814 		}
815 
816 		info = buffer.pointer;
817 		if (info->valid & ACPI_VALID_HID)
818 			hid = info->hardware_id.value;
819 		if (info->valid & ACPI_VALID_UID)
820 			uid = info->unique_id.value;
821 		if (info->valid & ACPI_VALID_CID)
822 			cid_list = &info->compatibility_id;
823 		if (info->valid & ACPI_VALID_ADR) {
824 			device->pnp.bus_address = info->address;
825 			device->flags.bus_address = 1;
826 		}
827 		break;
828 	case ACPI_BUS_TYPE_POWER:
829 		hid = ACPI_POWER_HID;
830 		break;
831 	case ACPI_BUS_TYPE_PROCESSOR:
832 		hid = ACPI_PROCESSOR_HID;
833 		break;
834 	case ACPI_BUS_TYPE_SYSTEM:
835 		hid = ACPI_SYSTEM_HID;
836 		break;
837 	case ACPI_BUS_TYPE_THERMAL:
838 		hid = ACPI_THERMAL_HID;
839 		break;
840 	case ACPI_BUS_TYPE_POWER_BUTTON:
841 		hid = ACPI_BUTTON_HID_POWERF;
842 		break;
843 	case ACPI_BUS_TYPE_SLEEP_BUTTON:
844 		hid = ACPI_BUTTON_HID_SLEEPF;
845 		break;
846 	}
847 
848 	/*
849 	 * \_SB
850 	 * ----
851 	 * Fix for the system root bus device -- the only root-level device.
852 	 */
853 	if (((acpi_handle)parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
854 		hid = ACPI_BUS_HID;
855 		strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
856 		strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
857 	}
858 
859 	if (hid) {
860 		strcpy(device->pnp.hardware_id, hid);
861 		device->flags.hardware_id = 1;
862 	}
863 	if (uid) {
864 		strcpy(device->pnp.unique_id, uid);
865 		device->flags.unique_id = 1;
866 	}
867 	if (cid_list) {
868 		device->pnp.cid_list = kmalloc(cid_list->size, GFP_KERNEL);
869 		if (device->pnp.cid_list)
870 			memcpy(device->pnp.cid_list, cid_list, cid_list->size);
871 		else
872 			printk(KERN_ERR "Memory allocation error\n");
873 	}
874 
875 	acpi_os_free(buffer.pointer);
876 }
877 
878 static int acpi_device_set_context(struct acpi_device *device, int type)
879 {
880 	acpi_status status = AE_OK;
881 	int result = 0;
882 	/*
883 	 * Context
884 	 * -------
885 	 * Attach this 'struct acpi_device' to the ACPI object.  This makes
886 	 * resolutions from handle->device very efficient.  Note that we need
887 	 * to be careful with fixed-feature devices as they all attach to the
888 	 * root object.
889 	 */
890 	if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
891 	    type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
892 		status = acpi_attach_data(device->handle,
893 					  acpi_bus_data_handler, device);
894 
895 		if (ACPI_FAILURE(status)) {
896 			printk("Error attaching device data\n");
897 			result = -ENODEV;
898 		}
899 	}
900 	return result;
901 }
902 
903 static void acpi_device_get_debug_info(struct acpi_device *device,
904 				       acpi_handle handle, int type)
905 {
906 #ifdef CONFIG_ACPI_DEBUG_OUTPUT
907 	char *type_string = NULL;
908 	char name[80] = { '?', '\0' };
909 	struct acpi_buffer buffer = { sizeof(name), name };
910 
911 	switch (type) {
912 	case ACPI_BUS_TYPE_DEVICE:
913 		type_string = "Device";
914 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
915 		break;
916 	case ACPI_BUS_TYPE_POWER:
917 		type_string = "Power Resource";
918 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
919 		break;
920 	case ACPI_BUS_TYPE_PROCESSOR:
921 		type_string = "Processor";
922 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
923 		break;
924 	case ACPI_BUS_TYPE_SYSTEM:
925 		type_string = "System";
926 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
927 		break;
928 	case ACPI_BUS_TYPE_THERMAL:
929 		type_string = "Thermal Zone";
930 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
931 		break;
932 	case ACPI_BUS_TYPE_POWER_BUTTON:
933 		type_string = "Power Button";
934 		sprintf(name, "PWRB");
935 		break;
936 	case ACPI_BUS_TYPE_SLEEP_BUTTON:
937 		type_string = "Sleep Button";
938 		sprintf(name, "SLPB");
939 		break;
940 	}
941 
942 	printk(KERN_DEBUG "Found %s %s [%p]\n", type_string, name, handle);
943 #endif				/*CONFIG_ACPI_DEBUG_OUTPUT */
944 }
945 
946 static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
947 {
948 	int result = 0;
949 	struct acpi_driver *driver;
950 
951 	ACPI_FUNCTION_TRACE("acpi_bus_remove");
952 
953 	if (!dev)
954 		return_VALUE(-EINVAL);
955 
956 	driver = dev->driver;
957 
958 	if ((driver) && (driver->ops.remove)) {
959 
960 		if (driver->ops.stop) {
961 			result = driver->ops.stop(dev, ACPI_BUS_REMOVAL_EJECT);
962 			if (result)
963 				return_VALUE(result);
964 		}
965 
966 		result = dev->driver->ops.remove(dev, ACPI_BUS_REMOVAL_EJECT);
967 		if (result) {
968 			return_VALUE(result);
969 		}
970 
971 		atomic_dec(&dev->driver->references);
972 		dev->driver = NULL;
973 		acpi_driver_data(dev) = NULL;
974 	}
975 
976 	if (!rmdevice)
977 		return_VALUE(0);
978 
979 	if (dev->flags.bus_address) {
980 		if ((dev->parent) && (dev->parent->ops.unbind))
981 			dev->parent->ops.unbind(dev);
982 	}
983 
984 	acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
985 
986 	return_VALUE(0);
987 }
988 
989 static int
990 acpi_add_single_object(struct acpi_device **child,
991 		       struct acpi_device *parent, acpi_handle handle, int type)
992 {
993 	int result = 0;
994 	struct acpi_device *device = NULL;
995 
996 	ACPI_FUNCTION_TRACE("acpi_add_single_object");
997 
998 	if (!child)
999 		return_VALUE(-EINVAL);
1000 
1001 	device = kmalloc(sizeof(struct acpi_device), GFP_KERNEL);
1002 	if (!device) {
1003 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Memory allocation error\n"));
1004 		return_VALUE(-ENOMEM);
1005 	}
1006 	memset(device, 0, sizeof(struct acpi_device));
1007 
1008 	device->handle = handle;
1009 	device->parent = parent;
1010 
1011 	acpi_device_get_busid(device, handle, type);
1012 
1013 	/*
1014 	 * Flags
1015 	 * -----
1016 	 * Get prior to calling acpi_bus_get_status() so we know whether
1017 	 * or not _STA is present.  Note that we only look for object
1018 	 * handles -- cannot evaluate objects until we know the device is
1019 	 * present and properly initialized.
1020 	 */
1021 	result = acpi_bus_get_flags(device);
1022 	if (result)
1023 		goto end;
1024 
1025 	/*
1026 	 * Status
1027 	 * ------
1028 	 * See if the device is present.  We always assume that non-Device
1029 	 * and non-Processor objects (e.g. thermal zones, power resources,
1030 	 * etc.) are present, functioning, etc. (at least when parent object
1031 	 * is present).  Note that _STA has a different meaning for some
1032 	 * objects (e.g. power resources) so we need to be careful how we use
1033 	 * it.
1034 	 */
1035 	switch (type) {
1036 	case ACPI_BUS_TYPE_PROCESSOR:
1037 	case ACPI_BUS_TYPE_DEVICE:
1038 		result = acpi_bus_get_status(device);
1039 		if (ACPI_FAILURE(result) || !device->status.present) {
1040 			result = -ENOENT;
1041 			goto end;
1042 		}
1043 		break;
1044 	default:
1045 		STRUCT_TO_INT(device->status) = 0x0F;
1046 		break;
1047 	}
1048 
1049 	/*
1050 	 * Initialize Device
1051 	 * -----------------
1052 	 * TBD: Synch with Core's enumeration/initialization process.
1053 	 */
1054 
1055 	/*
1056 	 * Hardware ID, Unique ID, & Bus Address
1057 	 * -------------------------------------
1058 	 */
1059 	acpi_device_set_id(device, parent, handle, type);
1060 
1061 	/*
1062 	 * Power Management
1063 	 * ----------------
1064 	 */
1065 	if (device->flags.power_manageable) {
1066 		result = acpi_bus_get_power_flags(device);
1067 		if (result)
1068 			goto end;
1069 	}
1070 
1071 	/*
1072 	 * Wakeup device management
1073 	 *-----------------------
1074 	 */
1075 	if (device->flags.wake_capable) {
1076 		result = acpi_bus_get_wakeup_device_flags(device);
1077 		if (result)
1078 			goto end;
1079 	}
1080 
1081 	/*
1082 	 * Performance Management
1083 	 * ----------------------
1084 	 */
1085 	if (device->flags.performance_manageable) {
1086 		result = acpi_bus_get_perf_flags(device);
1087 		if (result)
1088 			goto end;
1089 	}
1090 
1091 	if ((result = acpi_device_set_context(device, type)))
1092 		goto end;
1093 
1094 	acpi_device_get_debug_info(device, handle, type);
1095 
1096 	acpi_device_register(device, parent);
1097 
1098 	/*
1099 	 * Bind _ADR-Based Devices
1100 	 * -----------------------
1101 	 * If there's a a bus address (_ADR) then we utilize the parent's
1102 	 * 'bind' function (if exists) to bind the ACPI- and natively-
1103 	 * enumerated device representations.
1104 	 */
1105 	if (device->flags.bus_address) {
1106 		if (device->parent && device->parent->ops.bind)
1107 			device->parent->ops.bind(device);
1108 	}
1109 
1110 	/*
1111 	 * Locate & Attach Driver
1112 	 * ----------------------
1113 	 * If there's a hardware id (_HID) or compatible ids (_CID) we check
1114 	 * to see if there's a driver installed for this kind of device.  Note
1115 	 * that drivers can install before or after a device is enumerated.
1116 	 *
1117 	 * TBD: Assumes LDM provides driver hot-plug capability.
1118 	 */
1119 	acpi_bus_find_driver(device);
1120 
1121       end:
1122 	if (!result)
1123 		*child = device;
1124 	else {
1125 		kfree(device->pnp.cid_list);
1126 		kfree(device);
1127 	}
1128 
1129 	return_VALUE(result);
1130 }
1131 
1132 static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
1133 {
1134 	acpi_status status = AE_OK;
1135 	struct acpi_device *parent = NULL;
1136 	struct acpi_device *child = NULL;
1137 	acpi_handle phandle = NULL;
1138 	acpi_handle chandle = NULL;
1139 	acpi_object_type type = 0;
1140 	u32 level = 1;
1141 
1142 	ACPI_FUNCTION_TRACE("acpi_bus_scan");
1143 
1144 	if (!start)
1145 		return_VALUE(-EINVAL);
1146 
1147 	parent = start;
1148 	phandle = start->handle;
1149 
1150 	/*
1151 	 * Parse through the ACPI namespace, identify all 'devices', and
1152 	 * create a new 'struct acpi_device' for each.
1153 	 */
1154 	while ((level > 0) && parent) {
1155 
1156 		status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1157 					      chandle, &chandle);
1158 
1159 		/*
1160 		 * If this scope is exhausted then move our way back up.
1161 		 */
1162 		if (ACPI_FAILURE(status)) {
1163 			level--;
1164 			chandle = phandle;
1165 			acpi_get_parent(phandle, &phandle);
1166 			if (parent->parent)
1167 				parent = parent->parent;
1168 			continue;
1169 		}
1170 
1171 		status = acpi_get_type(chandle, &type);
1172 		if (ACPI_FAILURE(status))
1173 			continue;
1174 
1175 		/*
1176 		 * If this is a scope object then parse it (depth-first).
1177 		 */
1178 		if (type == ACPI_TYPE_LOCAL_SCOPE) {
1179 			level++;
1180 			phandle = chandle;
1181 			chandle = NULL;
1182 			continue;
1183 		}
1184 
1185 		/*
1186 		 * We're only interested in objects that we consider 'devices'.
1187 		 */
1188 		switch (type) {
1189 		case ACPI_TYPE_DEVICE:
1190 			type = ACPI_BUS_TYPE_DEVICE;
1191 			break;
1192 		case ACPI_TYPE_PROCESSOR:
1193 			type = ACPI_BUS_TYPE_PROCESSOR;
1194 			break;
1195 		case ACPI_TYPE_THERMAL:
1196 			type = ACPI_BUS_TYPE_THERMAL;
1197 			break;
1198 		case ACPI_TYPE_POWER:
1199 			type = ACPI_BUS_TYPE_POWER;
1200 			break;
1201 		default:
1202 			continue;
1203 		}
1204 
1205 		if (ops->acpi_op_add)
1206 			status = acpi_add_single_object(&child, parent,
1207 							chandle, type);
1208 		else
1209 			status = acpi_bus_get_device(chandle, &child);
1210 
1211 		if (ACPI_FAILURE(status))
1212 			continue;
1213 
1214 		if (ops->acpi_op_start) {
1215 			status = acpi_start_single_object(child);
1216 			if (ACPI_FAILURE(status))
1217 				continue;
1218 		}
1219 
1220 		/*
1221 		 * If the device is present, enabled, and functioning then
1222 		 * parse its scope (depth-first).  Note that we need to
1223 		 * represent absent devices to facilitate PnP notifications
1224 		 * -- but only the subtree head (not all of its children,
1225 		 * which will be enumerated when the parent is inserted).
1226 		 *
1227 		 * TBD: Need notifications and other detection mechanisms
1228 		 *      in place before we can fully implement this.
1229 		 */
1230 		if (child->status.present) {
1231 			status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
1232 						      NULL, NULL);
1233 			if (ACPI_SUCCESS(status)) {
1234 				level++;
1235 				phandle = chandle;
1236 				chandle = NULL;
1237 				parent = child;
1238 			}
1239 		}
1240 	}
1241 
1242 	return_VALUE(0);
1243 }
1244 
1245 int
1246 acpi_bus_add(struct acpi_device **child,
1247 	     struct acpi_device *parent, acpi_handle handle, int type)
1248 {
1249 	int result;
1250 	struct acpi_bus_ops ops;
1251 
1252 	ACPI_FUNCTION_TRACE("acpi_bus_add");
1253 
1254 	result = acpi_add_single_object(child, parent, handle, type);
1255 	if (!result) {
1256 		memset(&ops, 0, sizeof(ops));
1257 		ops.acpi_op_add = 1;
1258 		result = acpi_bus_scan(*child, &ops);
1259 	}
1260 	return_VALUE(result);
1261 }
1262 
1263 EXPORT_SYMBOL(acpi_bus_add);
1264 
1265 int acpi_bus_start(struct acpi_device *device)
1266 {
1267 	int result;
1268 	struct acpi_bus_ops ops;
1269 
1270 	ACPI_FUNCTION_TRACE("acpi_bus_start");
1271 
1272 	if (!device)
1273 		return_VALUE(-EINVAL);
1274 
1275 	result = acpi_start_single_object(device);
1276 	if (!result) {
1277 		memset(&ops, 0, sizeof(ops));
1278 		ops.acpi_op_start = 1;
1279 		result = acpi_bus_scan(device, &ops);
1280 	}
1281 	return_VALUE(result);
1282 }
1283 
1284 EXPORT_SYMBOL(acpi_bus_start);
1285 
1286 int acpi_bus_trim(struct acpi_device *start, int rmdevice)
1287 {
1288 	acpi_status status;
1289 	struct acpi_device *parent, *child;
1290 	acpi_handle phandle, chandle;
1291 	acpi_object_type type;
1292 	u32 level = 1;
1293 	int err = 0;
1294 
1295 	parent = start;
1296 	phandle = start->handle;
1297 	child = chandle = NULL;
1298 
1299 	while ((level > 0) && parent && (!err)) {
1300 		status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1301 					      chandle, &chandle);
1302 
1303 		/*
1304 		 * If this scope is exhausted then move our way back up.
1305 		 */
1306 		if (ACPI_FAILURE(status)) {
1307 			level--;
1308 			chandle = phandle;
1309 			acpi_get_parent(phandle, &phandle);
1310 			child = parent;
1311 			parent = parent->parent;
1312 
1313 			if (level == 0)
1314 				err = acpi_bus_remove(child, rmdevice);
1315 			else
1316 				err = acpi_bus_remove(child, 1);
1317 
1318 			continue;
1319 		}
1320 
1321 		status = acpi_get_type(chandle, &type);
1322 		if (ACPI_FAILURE(status)) {
1323 			continue;
1324 		}
1325 		/*
1326 		 * If there is a device corresponding to chandle then
1327 		 * parse it (depth-first).
1328 		 */
1329 		if (acpi_bus_get_device(chandle, &child) == 0) {
1330 			level++;
1331 			phandle = chandle;
1332 			chandle = NULL;
1333 			parent = child;
1334 		}
1335 		continue;
1336 	}
1337 	return err;
1338 }
1339 EXPORT_SYMBOL_GPL(acpi_bus_trim);
1340 
1341 
1342 static int acpi_bus_scan_fixed(struct acpi_device *root)
1343 {
1344 	int result = 0;
1345 	struct acpi_device *device = NULL;
1346 
1347 	ACPI_FUNCTION_TRACE("acpi_bus_scan_fixed");
1348 
1349 	if (!root)
1350 		return_VALUE(-ENODEV);
1351 
1352 	/*
1353 	 * Enumerate all fixed-feature devices.
1354 	 */
1355 	if (acpi_fadt.pwr_button == 0) {
1356 		result = acpi_add_single_object(&device, acpi_root,
1357 						NULL,
1358 						ACPI_BUS_TYPE_POWER_BUTTON);
1359 		if (!result)
1360 			result = acpi_start_single_object(device);
1361 	}
1362 
1363 	if (acpi_fadt.sleep_button == 0) {
1364 		result = acpi_add_single_object(&device, acpi_root,
1365 						NULL,
1366 						ACPI_BUS_TYPE_SLEEP_BUTTON);
1367 		if (!result)
1368 			result = acpi_start_single_object(device);
1369 	}
1370 
1371 	return_VALUE(result);
1372 }
1373 
1374 static int __init acpi_scan_init(void)
1375 {
1376 	int result;
1377 	struct acpi_bus_ops ops;
1378 
1379 	ACPI_FUNCTION_TRACE("acpi_scan_init");
1380 
1381 	if (acpi_disabled)
1382 		return_VALUE(0);
1383 
1384 	kset_register(&acpi_namespace_kset);
1385 
1386 	/*
1387 	 * Create the root device in the bus's device tree
1388 	 */
1389 	result = acpi_add_single_object(&acpi_root, NULL, ACPI_ROOT_OBJECT,
1390 					ACPI_BUS_TYPE_SYSTEM);
1391 	if (result)
1392 		goto Done;
1393 
1394 	result = acpi_start_single_object(acpi_root);
1395 
1396 	/*
1397 	 * Enumerate devices in the ACPI namespace.
1398 	 */
1399 	result = acpi_bus_scan_fixed(acpi_root);
1400 	if (!result) {
1401 		memset(&ops, 0, sizeof(ops));
1402 		ops.acpi_op_add = 1;
1403 		ops.acpi_op_start = 1;
1404 		result = acpi_bus_scan(acpi_root, &ops);
1405 	}
1406 
1407 	if (result)
1408 		acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);
1409 
1410       Done:
1411 	return_VALUE(result);
1412 }
1413 
1414 subsys_initcall(acpi_scan_init);
1415