xref: /linux/drivers/acpi/scan.c (revision 5e8d780d745c1619aba81fe7166c5a4b5cad2b84)
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 void 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 }
162 
163 void acpi_bus_data_handler(acpi_handle handle, u32 function, void *context)
164 {
165 	ACPI_FUNCTION_TRACE("acpi_bus_data_handler");
166 
167 	/* TBD */
168 
169 	return_VOID;
170 }
171 
172 static int acpi_bus_get_power_flags(struct acpi_device *device)
173 {
174 	acpi_status status = 0;
175 	acpi_handle handle = NULL;
176 	u32 i = 0;
177 
178 	ACPI_FUNCTION_TRACE("acpi_bus_get_power_flags");
179 
180 	/*
181 	 * Power Management Flags
182 	 */
183 	status = acpi_get_handle(device->handle, "_PSC", &handle);
184 	if (ACPI_SUCCESS(status))
185 		device->power.flags.explicit_get = 1;
186 	status = acpi_get_handle(device->handle, "_IRC", &handle);
187 	if (ACPI_SUCCESS(status))
188 		device->power.flags.inrush_current = 1;
189 
190 	/*
191 	 * Enumerate supported power management states
192 	 */
193 	for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
194 		struct acpi_device_power_state *ps = &device->power.states[i];
195 		char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };
196 
197 		/* Evaluate "_PRx" to se if power resources are referenced */
198 		acpi_evaluate_reference(device->handle, object_name, NULL,
199 					&ps->resources);
200 		if (ps->resources.count) {
201 			device->power.flags.power_resources = 1;
202 			ps->flags.valid = 1;
203 		}
204 
205 		/* Evaluate "_PSx" to see if we can do explicit sets */
206 		object_name[2] = 'S';
207 		status = acpi_get_handle(device->handle, object_name, &handle);
208 		if (ACPI_SUCCESS(status)) {
209 			ps->flags.explicit_set = 1;
210 			ps->flags.valid = 1;
211 		}
212 
213 		/* State is valid if we have some power control */
214 		if (ps->resources.count || ps->flags.explicit_set)
215 			ps->flags.valid = 1;
216 
217 		ps->power = -1;	/* Unknown - driver assigned */
218 		ps->latency = -1;	/* Unknown - driver assigned */
219 	}
220 
221 	/* Set defaults for D0 and D3 states (always valid) */
222 	device->power.states[ACPI_STATE_D0].flags.valid = 1;
223 	device->power.states[ACPI_STATE_D0].power = 100;
224 	device->power.states[ACPI_STATE_D3].flags.valid = 1;
225 	device->power.states[ACPI_STATE_D3].power = 0;
226 
227 	/* TBD: System wake support and resource requirements. */
228 
229 	device->power.state = ACPI_STATE_UNKNOWN;
230 
231 	return_VALUE(0);
232 }
233 
234 int acpi_match_ids(struct acpi_device *device, char *ids)
235 {
236 	if (device->flags.hardware_id)
237 		if (strstr(ids, device->pnp.hardware_id))
238 			return 0;
239 
240 	if (device->flags.compatible_ids) {
241 		struct acpi_compatible_id_list *cid_list = device->pnp.cid_list;
242 		int i;
243 
244 		/* compare multiple _CID entries against driver ids */
245 		for (i = 0; i < cid_list->count; i++) {
246 			if (strstr(ids, cid_list->id[i].value))
247 				return 0;
248 		}
249 	}
250 	return -ENOENT;
251 }
252 
253 static acpi_status
254 acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
255 					     union acpi_object *package)
256 {
257 	int i = 0;
258 	union acpi_object *element = NULL;
259 
260 	if (!device || !package || (package->package.count < 2))
261 		return AE_BAD_PARAMETER;
262 
263 	element = &(package->package.elements[0]);
264 	if (!element)
265 		return AE_BAD_PARAMETER;
266 	if (element->type == ACPI_TYPE_PACKAGE) {
267 		if ((element->package.count < 2) ||
268 		    (element->package.elements[0].type !=
269 		     ACPI_TYPE_LOCAL_REFERENCE)
270 		    || (element->package.elements[1].type != ACPI_TYPE_INTEGER))
271 			return AE_BAD_DATA;
272 		device->wakeup.gpe_device =
273 		    element->package.elements[0].reference.handle;
274 		device->wakeup.gpe_number =
275 		    (u32) element->package.elements[1].integer.value;
276 	} else if (element->type == ACPI_TYPE_INTEGER) {
277 		device->wakeup.gpe_number = element->integer.value;
278 	} else
279 		return AE_BAD_DATA;
280 
281 	element = &(package->package.elements[1]);
282 	if (element->type != ACPI_TYPE_INTEGER) {
283 		return AE_BAD_DATA;
284 	}
285 	device->wakeup.sleep_state = element->integer.value;
286 
287 	if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
288 		return AE_NO_MEMORY;
289 	}
290 	device->wakeup.resources.count = package->package.count - 2;
291 	for (i = 0; i < device->wakeup.resources.count; i++) {
292 		element = &(package->package.elements[i + 2]);
293 		if (element->type != ACPI_TYPE_ANY) {
294 			return AE_BAD_DATA;
295 		}
296 
297 		device->wakeup.resources.handles[i] = element->reference.handle;
298 	}
299 
300 	return AE_OK;
301 }
302 
303 static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
304 {
305 	acpi_status status = 0;
306 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
307 	union acpi_object *package = NULL;
308 
309 	ACPI_FUNCTION_TRACE("acpi_bus_get_wakeup_flags");
310 
311 	/* _PRW */
312 	status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
313 	if (ACPI_FAILURE(status)) {
314 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRW\n"));
315 		goto end;
316 	}
317 
318 	package = (union acpi_object *)buffer.pointer;
319 	status = acpi_bus_extract_wakeup_device_power_package(device, package);
320 	if (ACPI_FAILURE(status)) {
321 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
322 				  "Error extracting _PRW package\n"));
323 		goto end;
324 	}
325 
326 	acpi_os_free(buffer.pointer);
327 
328 	device->wakeup.flags.valid = 1;
329 	/* Power button, Lid switch always enable wakeup */
330 	if (!acpi_match_ids(device, "PNP0C0D,PNP0C0C,PNP0C0E"))
331 		device->wakeup.flags.run_wake = 1;
332 
333       end:
334 	if (ACPI_FAILURE(status))
335 		device->flags.wake_capable = 0;
336 	return_VALUE(0);
337 }
338 
339 /* --------------------------------------------------------------------------
340 		ACPI sysfs device file support
341    -------------------------------------------------------------------------- */
342 static ssize_t acpi_eject_store(struct acpi_device *device,
343 				const char *buf, size_t count);
344 
345 #define ACPI_DEVICE_ATTR(_name,_mode,_show,_store) \
346 static struct acpi_device_attribute acpi_device_attr_##_name = \
347 		__ATTR(_name, _mode, _show, _store)
348 
349 ACPI_DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
350 
351 /**
352  * setup_sys_fs_device_files - sets up the device files under device namespace
353  * @dev:	acpi_device object
354  * @func:	function pointer to create or destroy the device file
355  */
356 static void
357 setup_sys_fs_device_files(struct acpi_device *dev,
358 			  acpi_device_sysfs_files * func)
359 {
360 	acpi_status status;
361 	acpi_handle temp = NULL;
362 
363 	/*
364 	 * If device has _EJ0, 'eject' file is created that is used to trigger
365 	 * hot-removal function from userland.
366 	 */
367 	status = acpi_get_handle(dev->handle, "_EJ0", &temp);
368 	if (ACPI_SUCCESS(status))
369 		(*(func)) (&dev->kobj, &acpi_device_attr_eject.attr);
370 }
371 
372 static int acpi_eject_operation(acpi_handle handle, int lockable)
373 {
374 	struct acpi_object_list arg_list;
375 	union acpi_object arg;
376 	acpi_status status = AE_OK;
377 
378 	/*
379 	 * TBD: evaluate _PS3?
380 	 */
381 
382 	if (lockable) {
383 		arg_list.count = 1;
384 		arg_list.pointer = &arg;
385 		arg.type = ACPI_TYPE_INTEGER;
386 		arg.integer.value = 0;
387 		acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
388 	}
389 
390 	arg_list.count = 1;
391 	arg_list.pointer = &arg;
392 	arg.type = ACPI_TYPE_INTEGER;
393 	arg.integer.value = 1;
394 
395 	/*
396 	 * TBD: _EJD support.
397 	 */
398 
399 	status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
400 	if (ACPI_FAILURE(status)) {
401 		return (-ENODEV);
402 	}
403 
404 	return (0);
405 }
406 
407 static ssize_t
408 acpi_eject_store(struct acpi_device *device, const char *buf, size_t count)
409 {
410 	int result;
411 	int ret = count;
412 	int islockable;
413 	acpi_status status;
414 	acpi_handle handle;
415 	acpi_object_type type = 0;
416 
417 	if ((!count) || (buf[0] != '1')) {
418 		return -EINVAL;
419 	}
420 #ifndef FORCE_EJECT
421 	if (device->driver == NULL) {
422 		ret = -ENODEV;
423 		goto err;
424 	}
425 #endif
426 	status = acpi_get_type(device->handle, &type);
427 	if (ACPI_FAILURE(status) || (!device->flags.ejectable)) {
428 		ret = -ENODEV;
429 		goto err;
430 	}
431 
432 	islockable = device->flags.lockable;
433 	handle = device->handle;
434 
435 	result = acpi_bus_trim(device, 1);
436 
437 	if (!result)
438 		result = acpi_eject_operation(handle, islockable);
439 
440 	if (result) {
441 		ret = -EBUSY;
442 	}
443       err:
444 	return ret;
445 }
446 
447 /* --------------------------------------------------------------------------
448                               Performance Management
449    -------------------------------------------------------------------------- */
450 
451 static int acpi_bus_get_perf_flags(struct acpi_device *device)
452 {
453 	device->performance.state = ACPI_STATE_UNKNOWN;
454 	return 0;
455 }
456 
457 /* --------------------------------------------------------------------------
458                                  Driver Management
459    -------------------------------------------------------------------------- */
460 
461 static LIST_HEAD(acpi_bus_drivers);
462 
463 /**
464  * acpi_bus_match - match device IDs to driver's supported IDs
465  * @device: the device that we are trying to match to a driver
466  * @driver: driver whose device id table is being checked
467  *
468  * Checks the device's hardware (_HID) or compatible (_CID) ids to see if it
469  * matches the specified driver's criteria.
470  */
471 static int
472 acpi_bus_match(struct acpi_device *device, struct acpi_driver *driver)
473 {
474 	if (driver && driver->ops.match)
475 		return driver->ops.match(device, driver);
476 	return acpi_match_ids(device, driver->ids);
477 }
478 
479 /**
480  * acpi_bus_driver_init - add a device to a driver
481  * @device: the device to add and initialize
482  * @driver: driver for the device
483  *
484  * Used to initialize a device via its device driver.  Called whenever a
485  * driver is bound to a device.  Invokes the driver's add() and start() ops.
486  */
487 static int
488 acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
489 {
490 	int result = 0;
491 
492 	ACPI_FUNCTION_TRACE("acpi_bus_driver_init");
493 
494 	if (!device || !driver)
495 		return_VALUE(-EINVAL);
496 
497 	if (!driver->ops.add)
498 		return_VALUE(-ENOSYS);
499 
500 	result = driver->ops.add(device);
501 	if (result) {
502 		device->driver = NULL;
503 		acpi_driver_data(device) = NULL;
504 		return_VALUE(result);
505 	}
506 
507 	device->driver = driver;
508 
509 	/*
510 	 * TBD - Configuration Management: Assign resources to device based
511 	 * upon possible configuration and currently allocated resources.
512 	 */
513 
514 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
515 			  "Driver successfully bound to device\n"));
516 	return_VALUE(0);
517 }
518 
519 static int acpi_start_single_object(struct acpi_device *device)
520 {
521 	int result = 0;
522 	struct acpi_driver *driver;
523 
524 	ACPI_FUNCTION_TRACE("acpi_start_single_object");
525 
526 	if (!(driver = device->driver))
527 		return_VALUE(0);
528 
529 	if (driver->ops.start) {
530 		result = driver->ops.start(device);
531 		if (result && driver->ops.remove)
532 			driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
533 	}
534 
535 	return_VALUE(result);
536 }
537 
538 static void acpi_driver_attach(struct acpi_driver *drv)
539 {
540 	struct list_head *node, *next;
541 
542 	ACPI_FUNCTION_TRACE("acpi_driver_attach");
543 
544 	spin_lock(&acpi_device_lock);
545 	list_for_each_safe(node, next, &acpi_device_list) {
546 		struct acpi_device *dev =
547 		    container_of(node, struct acpi_device, g_list);
548 
549 		if (dev->driver || !dev->status.present)
550 			continue;
551 		spin_unlock(&acpi_device_lock);
552 
553 		if (!acpi_bus_match(dev, drv)) {
554 			if (!acpi_bus_driver_init(dev, drv)) {
555 				acpi_start_single_object(dev);
556 				atomic_inc(&drv->references);
557 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
558 						  "Found driver [%s] for device [%s]\n",
559 						  drv->name, dev->pnp.bus_id));
560 			}
561 		}
562 		spin_lock(&acpi_device_lock);
563 	}
564 	spin_unlock(&acpi_device_lock);
565 }
566 
567 static void acpi_driver_detach(struct acpi_driver *drv)
568 {
569 	struct list_head *node, *next;
570 
571 	ACPI_FUNCTION_TRACE("acpi_driver_detach");
572 
573 	spin_lock(&acpi_device_lock);
574 	list_for_each_safe(node, next, &acpi_device_list) {
575 		struct acpi_device *dev =
576 		    container_of(node, struct acpi_device, g_list);
577 
578 		if (dev->driver == drv) {
579 			spin_unlock(&acpi_device_lock);
580 			if (drv->ops.remove)
581 				drv->ops.remove(dev, ACPI_BUS_REMOVAL_NORMAL);
582 			spin_lock(&acpi_device_lock);
583 			dev->driver = NULL;
584 			dev->driver_data = NULL;
585 			atomic_dec(&drv->references);
586 		}
587 	}
588 	spin_unlock(&acpi_device_lock);
589 }
590 
591 /**
592  * acpi_bus_register_driver - register a driver with the ACPI bus
593  * @driver: driver being registered
594  *
595  * Registers a driver with the ACPI bus.  Searches the namespace for all
596  * devices that match the driver's criteria and binds.  Returns zero for
597  * success or a negative error status for failure.
598  */
599 int acpi_bus_register_driver(struct acpi_driver *driver)
600 {
601 	ACPI_FUNCTION_TRACE("acpi_bus_register_driver");
602 
603 	if (acpi_disabled)
604 		return_VALUE(-ENODEV);
605 
606 	spin_lock(&acpi_device_lock);
607 	list_add_tail(&driver->node, &acpi_bus_drivers);
608 	spin_unlock(&acpi_device_lock);
609 	acpi_driver_attach(driver);
610 
611 	return_VALUE(0);
612 }
613 
614 EXPORT_SYMBOL(acpi_bus_register_driver);
615 
616 /**
617  * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
618  * @driver: driver to unregister
619  *
620  * Unregisters a driver with the ACPI bus.  Searches the namespace for all
621  * devices that match the driver's criteria and unbinds.
622  */
623 void acpi_bus_unregister_driver(struct acpi_driver *driver)
624 {
625 	acpi_driver_detach(driver);
626 
627 	if (!atomic_read(&driver->references)) {
628 		spin_lock(&acpi_device_lock);
629 		list_del_init(&driver->node);
630 		spin_unlock(&acpi_device_lock);
631 	}
632 	return;
633 }
634 
635 EXPORT_SYMBOL(acpi_bus_unregister_driver);
636 
637 /**
638  * acpi_bus_find_driver - check if there is a driver installed for the device
639  * @device: device that we are trying to find a supporting driver for
640  *
641  * Parses the list of registered drivers looking for a driver applicable for
642  * the specified device.
643  */
644 static int acpi_bus_find_driver(struct acpi_device *device)
645 {
646 	int result = 0;
647 	struct list_head *node, *next;
648 
649 	ACPI_FUNCTION_TRACE("acpi_bus_find_driver");
650 
651 	spin_lock(&acpi_device_lock);
652 	list_for_each_safe(node, next, &acpi_bus_drivers) {
653 		struct acpi_driver *driver =
654 		    container_of(node, struct acpi_driver, node);
655 
656 		atomic_inc(&driver->references);
657 		spin_unlock(&acpi_device_lock);
658 		if (!acpi_bus_match(device, driver)) {
659 			result = acpi_bus_driver_init(device, driver);
660 			if (!result)
661 				goto Done;
662 		}
663 		atomic_dec(&driver->references);
664 		spin_lock(&acpi_device_lock);
665 	}
666 	spin_unlock(&acpi_device_lock);
667 
668       Done:
669 	return_VALUE(result);
670 }
671 
672 /* --------------------------------------------------------------------------
673                                  Device Enumeration
674    -------------------------------------------------------------------------- */
675 
676 static int acpi_bus_get_flags(struct acpi_device *device)
677 {
678 	acpi_status status = AE_OK;
679 	acpi_handle temp = NULL;
680 
681 	ACPI_FUNCTION_TRACE("acpi_bus_get_flags");
682 
683 	/* Presence of _STA indicates 'dynamic_status' */
684 	status = acpi_get_handle(device->handle, "_STA", &temp);
685 	if (ACPI_SUCCESS(status))
686 		device->flags.dynamic_status = 1;
687 
688 	/* Presence of _CID indicates 'compatible_ids' */
689 	status = acpi_get_handle(device->handle, "_CID", &temp);
690 	if (ACPI_SUCCESS(status))
691 		device->flags.compatible_ids = 1;
692 
693 	/* Presence of _RMV indicates 'removable' */
694 	status = acpi_get_handle(device->handle, "_RMV", &temp);
695 	if (ACPI_SUCCESS(status))
696 		device->flags.removable = 1;
697 
698 	/* Presence of _EJD|_EJ0 indicates 'ejectable' */
699 	status = acpi_get_handle(device->handle, "_EJD", &temp);
700 	if (ACPI_SUCCESS(status))
701 		device->flags.ejectable = 1;
702 	else {
703 		status = acpi_get_handle(device->handle, "_EJ0", &temp);
704 		if (ACPI_SUCCESS(status))
705 			device->flags.ejectable = 1;
706 	}
707 
708 	/* Presence of _LCK indicates 'lockable' */
709 	status = acpi_get_handle(device->handle, "_LCK", &temp);
710 	if (ACPI_SUCCESS(status))
711 		device->flags.lockable = 1;
712 
713 	/* Presence of _PS0|_PR0 indicates 'power manageable' */
714 	status = acpi_get_handle(device->handle, "_PS0", &temp);
715 	if (ACPI_FAILURE(status))
716 		status = acpi_get_handle(device->handle, "_PR0", &temp);
717 	if (ACPI_SUCCESS(status))
718 		device->flags.power_manageable = 1;
719 
720 	/* Presence of _PRW indicates wake capable */
721 	status = acpi_get_handle(device->handle, "_PRW", &temp);
722 	if (ACPI_SUCCESS(status))
723 		device->flags.wake_capable = 1;
724 
725 	/* TBD: Peformance management */
726 
727 	return_VALUE(0);
728 }
729 
730 static void acpi_device_get_busid(struct acpi_device *device,
731 				  acpi_handle handle, int type)
732 {
733 	char bus_id[5] = { '?', 0 };
734 	struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
735 	int i = 0;
736 
737 	/*
738 	 * Bus ID
739 	 * ------
740 	 * The device's Bus ID is simply the object name.
741 	 * TBD: Shouldn't this value be unique (within the ACPI namespace)?
742 	 */
743 	switch (type) {
744 	case ACPI_BUS_TYPE_SYSTEM:
745 		strcpy(device->pnp.bus_id, "ACPI");
746 		break;
747 	case ACPI_BUS_TYPE_POWER_BUTTON:
748 		strcpy(device->pnp.bus_id, "PWRF");
749 		break;
750 	case ACPI_BUS_TYPE_SLEEP_BUTTON:
751 		strcpy(device->pnp.bus_id, "SLPF");
752 		break;
753 	default:
754 		acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
755 		/* Clean up trailing underscores (if any) */
756 		for (i = 3; i > 1; i--) {
757 			if (bus_id[i] == '_')
758 				bus_id[i] = '\0';
759 			else
760 				break;
761 		}
762 		strcpy(device->pnp.bus_id, bus_id);
763 		break;
764 	}
765 }
766 
767 static void acpi_device_set_id(struct acpi_device *device,
768 			       struct acpi_device *parent, acpi_handle handle,
769 			       int type)
770 {
771 	struct acpi_device_info *info;
772 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
773 	char *hid = NULL;
774 	char *uid = NULL;
775 	struct acpi_compatible_id_list *cid_list = NULL;
776 	acpi_status status;
777 
778 	switch (type) {
779 	case ACPI_BUS_TYPE_DEVICE:
780 		status = acpi_get_object_info(handle, &buffer);
781 		if (ACPI_FAILURE(status)) {
782 			printk("%s: Error reading device info\n", __FUNCTION__);
783 			return;
784 		}
785 
786 		info = buffer.pointer;
787 		if (info->valid & ACPI_VALID_HID)
788 			hid = info->hardware_id.value;
789 		if (info->valid & ACPI_VALID_UID)
790 			uid = info->unique_id.value;
791 		if (info->valid & ACPI_VALID_CID)
792 			cid_list = &info->compatibility_id;
793 		if (info->valid & ACPI_VALID_ADR) {
794 			device->pnp.bus_address = info->address;
795 			device->flags.bus_address = 1;
796 		}
797 		break;
798 	case ACPI_BUS_TYPE_POWER:
799 		hid = ACPI_POWER_HID;
800 		break;
801 	case ACPI_BUS_TYPE_PROCESSOR:
802 		hid = ACPI_PROCESSOR_HID;
803 		break;
804 	case ACPI_BUS_TYPE_SYSTEM:
805 		hid = ACPI_SYSTEM_HID;
806 		break;
807 	case ACPI_BUS_TYPE_THERMAL:
808 		hid = ACPI_THERMAL_HID;
809 		break;
810 	case ACPI_BUS_TYPE_POWER_BUTTON:
811 		hid = ACPI_BUTTON_HID_POWERF;
812 		break;
813 	case ACPI_BUS_TYPE_SLEEP_BUTTON:
814 		hid = ACPI_BUTTON_HID_SLEEPF;
815 		break;
816 	}
817 
818 	/*
819 	 * \_SB
820 	 * ----
821 	 * Fix for the system root bus device -- the only root-level device.
822 	 */
823 	if (((acpi_handle)parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
824 		hid = ACPI_BUS_HID;
825 		strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
826 		strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
827 	}
828 
829 	if (hid) {
830 		strcpy(device->pnp.hardware_id, hid);
831 		device->flags.hardware_id = 1;
832 	}
833 	if (uid) {
834 		strcpy(device->pnp.unique_id, uid);
835 		device->flags.unique_id = 1;
836 	}
837 	if (cid_list) {
838 		device->pnp.cid_list = kmalloc(cid_list->size, GFP_KERNEL);
839 		if (device->pnp.cid_list)
840 			memcpy(device->pnp.cid_list, cid_list, cid_list->size);
841 		else
842 			printk(KERN_ERR "Memory allocation error\n");
843 	}
844 
845 	acpi_os_free(buffer.pointer);
846 }
847 
848 static int acpi_device_set_context(struct acpi_device *device, int type)
849 {
850 	acpi_status status = AE_OK;
851 	int result = 0;
852 	/*
853 	 * Context
854 	 * -------
855 	 * Attach this 'struct acpi_device' to the ACPI object.  This makes
856 	 * resolutions from handle->device very efficient.  Note that we need
857 	 * to be careful with fixed-feature devices as they all attach to the
858 	 * root object.
859 	 */
860 	if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
861 	    type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
862 		status = acpi_attach_data(device->handle,
863 					  acpi_bus_data_handler, device);
864 
865 		if (ACPI_FAILURE(status)) {
866 			printk("Error attaching device data\n");
867 			result = -ENODEV;
868 		}
869 	}
870 	return result;
871 }
872 
873 static void acpi_device_get_debug_info(struct acpi_device *device,
874 				       acpi_handle handle, int type)
875 {
876 #ifdef CONFIG_ACPI_DEBUG_OUTPUT
877 	char *type_string = NULL;
878 	char name[80] = { '?', '\0' };
879 	struct acpi_buffer buffer = { sizeof(name), name };
880 
881 	switch (type) {
882 	case ACPI_BUS_TYPE_DEVICE:
883 		type_string = "Device";
884 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
885 		break;
886 	case ACPI_BUS_TYPE_POWER:
887 		type_string = "Power Resource";
888 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
889 		break;
890 	case ACPI_BUS_TYPE_PROCESSOR:
891 		type_string = "Processor";
892 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
893 		break;
894 	case ACPI_BUS_TYPE_SYSTEM:
895 		type_string = "System";
896 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
897 		break;
898 	case ACPI_BUS_TYPE_THERMAL:
899 		type_string = "Thermal Zone";
900 		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
901 		break;
902 	case ACPI_BUS_TYPE_POWER_BUTTON:
903 		type_string = "Power Button";
904 		sprintf(name, "PWRB");
905 		break;
906 	case ACPI_BUS_TYPE_SLEEP_BUTTON:
907 		type_string = "Sleep Button";
908 		sprintf(name, "SLPB");
909 		break;
910 	}
911 
912 	printk(KERN_DEBUG "Found %s %s [%p]\n", type_string, name, handle);
913 #endif				/*CONFIG_ACPI_DEBUG_OUTPUT */
914 }
915 
916 static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
917 {
918 	int result = 0;
919 	struct acpi_driver *driver;
920 
921 	ACPI_FUNCTION_TRACE("acpi_bus_remove");
922 
923 	if (!dev)
924 		return_VALUE(-EINVAL);
925 
926 	driver = dev->driver;
927 
928 	if ((driver) && (driver->ops.remove)) {
929 
930 		if (driver->ops.stop) {
931 			result = driver->ops.stop(dev, ACPI_BUS_REMOVAL_EJECT);
932 			if (result)
933 				return_VALUE(result);
934 		}
935 
936 		result = dev->driver->ops.remove(dev, ACPI_BUS_REMOVAL_EJECT);
937 		if (result) {
938 			return_VALUE(result);
939 		}
940 
941 		atomic_dec(&dev->driver->references);
942 		dev->driver = NULL;
943 		acpi_driver_data(dev) = NULL;
944 	}
945 
946 	if (!rmdevice)
947 		return_VALUE(0);
948 
949 	if (dev->flags.bus_address) {
950 		if ((dev->parent) && (dev->parent->ops.unbind))
951 			dev->parent->ops.unbind(dev);
952 	}
953 
954 	acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);
955 
956 	return_VALUE(0);
957 }
958 
959 static int
960 acpi_add_single_object(struct acpi_device **child,
961 		       struct acpi_device *parent, acpi_handle handle, int type)
962 {
963 	int result = 0;
964 	struct acpi_device *device = NULL;
965 
966 	ACPI_FUNCTION_TRACE("acpi_add_single_object");
967 
968 	if (!child)
969 		return_VALUE(-EINVAL);
970 
971 	device = kmalloc(sizeof(struct acpi_device), GFP_KERNEL);
972 	if (!device) {
973 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Memory allocation error\n"));
974 		return_VALUE(-ENOMEM);
975 	}
976 	memset(device, 0, sizeof(struct acpi_device));
977 
978 	device->handle = handle;
979 	device->parent = parent;
980 
981 	acpi_device_get_busid(device, handle, type);
982 
983 	/*
984 	 * Flags
985 	 * -----
986 	 * Get prior to calling acpi_bus_get_status() so we know whether
987 	 * or not _STA is present.  Note that we only look for object
988 	 * handles -- cannot evaluate objects until we know the device is
989 	 * present and properly initialized.
990 	 */
991 	result = acpi_bus_get_flags(device);
992 	if (result)
993 		goto end;
994 
995 	/*
996 	 * Status
997 	 * ------
998 	 * See if the device is present.  We always assume that non-Device
999 	 * and non-Processor objects (e.g. thermal zones, power resources,
1000 	 * etc.) are present, functioning, etc. (at least when parent object
1001 	 * is present).  Note that _STA has a different meaning for some
1002 	 * objects (e.g. power resources) so we need to be careful how we use
1003 	 * it.
1004 	 */
1005 	switch (type) {
1006 	case ACPI_BUS_TYPE_PROCESSOR:
1007 	case ACPI_BUS_TYPE_DEVICE:
1008 		result = acpi_bus_get_status(device);
1009 		if (ACPI_FAILURE(result) || !device->status.present) {
1010 			result = -ENOENT;
1011 			goto end;
1012 		}
1013 		break;
1014 	default:
1015 		STRUCT_TO_INT(device->status) = 0x0F;
1016 		break;
1017 	}
1018 
1019 	/*
1020 	 * Initialize Device
1021 	 * -----------------
1022 	 * TBD: Synch with Core's enumeration/initialization process.
1023 	 */
1024 
1025 	/*
1026 	 * Hardware ID, Unique ID, & Bus Address
1027 	 * -------------------------------------
1028 	 */
1029 	acpi_device_set_id(device, parent, handle, type);
1030 
1031 	/*
1032 	 * Power Management
1033 	 * ----------------
1034 	 */
1035 	if (device->flags.power_manageable) {
1036 		result = acpi_bus_get_power_flags(device);
1037 		if (result)
1038 			goto end;
1039 	}
1040 
1041 	/*
1042 	 * Wakeup device management
1043 	 *-----------------------
1044 	 */
1045 	if (device->flags.wake_capable) {
1046 		result = acpi_bus_get_wakeup_device_flags(device);
1047 		if (result)
1048 			goto end;
1049 	}
1050 
1051 	/*
1052 	 * Performance Management
1053 	 * ----------------------
1054 	 */
1055 	if (device->flags.performance_manageable) {
1056 		result = acpi_bus_get_perf_flags(device);
1057 		if (result)
1058 			goto end;
1059 	}
1060 
1061 	if ((result = acpi_device_set_context(device, type)))
1062 		goto end;
1063 
1064 	acpi_device_get_debug_info(device, handle, type);
1065 
1066 	acpi_device_register(device, parent);
1067 
1068 	/*
1069 	 * Bind _ADR-Based Devices
1070 	 * -----------------------
1071 	 * If there's a a bus address (_ADR) then we utilize the parent's
1072 	 * 'bind' function (if exists) to bind the ACPI- and natively-
1073 	 * enumerated device representations.
1074 	 */
1075 	if (device->flags.bus_address) {
1076 		if (device->parent && device->parent->ops.bind)
1077 			device->parent->ops.bind(device);
1078 	}
1079 
1080 	/*
1081 	 * Locate & Attach Driver
1082 	 * ----------------------
1083 	 * If there's a hardware id (_HID) or compatible ids (_CID) we check
1084 	 * to see if there's a driver installed for this kind of device.  Note
1085 	 * that drivers can install before or after a device is enumerated.
1086 	 *
1087 	 * TBD: Assumes LDM provides driver hot-plug capability.
1088 	 */
1089 	acpi_bus_find_driver(device);
1090 
1091       end:
1092 	if (!result)
1093 		*child = device;
1094 	else {
1095 		kfree(device->pnp.cid_list);
1096 		kfree(device);
1097 	}
1098 
1099 	return_VALUE(result);
1100 }
1101 
1102 static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
1103 {
1104 	acpi_status status = AE_OK;
1105 	struct acpi_device *parent = NULL;
1106 	struct acpi_device *child = NULL;
1107 	acpi_handle phandle = NULL;
1108 	acpi_handle chandle = NULL;
1109 	acpi_object_type type = 0;
1110 	u32 level = 1;
1111 
1112 	ACPI_FUNCTION_TRACE("acpi_bus_scan");
1113 
1114 	if (!start)
1115 		return_VALUE(-EINVAL);
1116 
1117 	parent = start;
1118 	phandle = start->handle;
1119 
1120 	/*
1121 	 * Parse through the ACPI namespace, identify all 'devices', and
1122 	 * create a new 'struct acpi_device' for each.
1123 	 */
1124 	while ((level > 0) && parent) {
1125 
1126 		status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1127 					      chandle, &chandle);
1128 
1129 		/*
1130 		 * If this scope is exhausted then move our way back up.
1131 		 */
1132 		if (ACPI_FAILURE(status)) {
1133 			level--;
1134 			chandle = phandle;
1135 			acpi_get_parent(phandle, &phandle);
1136 			if (parent->parent)
1137 				parent = parent->parent;
1138 			continue;
1139 		}
1140 
1141 		status = acpi_get_type(chandle, &type);
1142 		if (ACPI_FAILURE(status))
1143 			continue;
1144 
1145 		/*
1146 		 * If this is a scope object then parse it (depth-first).
1147 		 */
1148 		if (type == ACPI_TYPE_LOCAL_SCOPE) {
1149 			level++;
1150 			phandle = chandle;
1151 			chandle = NULL;
1152 			continue;
1153 		}
1154 
1155 		/*
1156 		 * We're only interested in objects that we consider 'devices'.
1157 		 */
1158 		switch (type) {
1159 		case ACPI_TYPE_DEVICE:
1160 			type = ACPI_BUS_TYPE_DEVICE;
1161 			break;
1162 		case ACPI_TYPE_PROCESSOR:
1163 			type = ACPI_BUS_TYPE_PROCESSOR;
1164 			break;
1165 		case ACPI_TYPE_THERMAL:
1166 			type = ACPI_BUS_TYPE_THERMAL;
1167 			break;
1168 		case ACPI_TYPE_POWER:
1169 			type = ACPI_BUS_TYPE_POWER;
1170 			break;
1171 		default:
1172 			continue;
1173 		}
1174 
1175 		if (ops->acpi_op_add)
1176 			status = acpi_add_single_object(&child, parent,
1177 							chandle, type);
1178 		else
1179 			status = acpi_bus_get_device(chandle, &child);
1180 
1181 		if (ACPI_FAILURE(status))
1182 			continue;
1183 
1184 		if (ops->acpi_op_start) {
1185 			status = acpi_start_single_object(child);
1186 			if (ACPI_FAILURE(status))
1187 				continue;
1188 		}
1189 
1190 		/*
1191 		 * If the device is present, enabled, and functioning then
1192 		 * parse its scope (depth-first).  Note that we need to
1193 		 * represent absent devices to facilitate PnP notifications
1194 		 * -- but only the subtree head (not all of its children,
1195 		 * which will be enumerated when the parent is inserted).
1196 		 *
1197 		 * TBD: Need notifications and other detection mechanisms
1198 		 *      in place before we can fully implement this.
1199 		 */
1200 		if (child->status.present) {
1201 			status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
1202 						      NULL, NULL);
1203 			if (ACPI_SUCCESS(status)) {
1204 				level++;
1205 				phandle = chandle;
1206 				chandle = NULL;
1207 				parent = child;
1208 			}
1209 		}
1210 	}
1211 
1212 	return_VALUE(0);
1213 }
1214 
1215 int
1216 acpi_bus_add(struct acpi_device **child,
1217 	     struct acpi_device *parent, acpi_handle handle, int type)
1218 {
1219 	int result;
1220 	struct acpi_bus_ops ops;
1221 
1222 	ACPI_FUNCTION_TRACE("acpi_bus_add");
1223 
1224 	result = acpi_add_single_object(child, parent, handle, type);
1225 	if (!result) {
1226 		memset(&ops, 0, sizeof(ops));
1227 		ops.acpi_op_add = 1;
1228 		result = acpi_bus_scan(*child, &ops);
1229 	}
1230 	return_VALUE(result);
1231 }
1232 
1233 EXPORT_SYMBOL(acpi_bus_add);
1234 
1235 int acpi_bus_start(struct acpi_device *device)
1236 {
1237 	int result;
1238 	struct acpi_bus_ops ops;
1239 
1240 	ACPI_FUNCTION_TRACE("acpi_bus_start");
1241 
1242 	if (!device)
1243 		return_VALUE(-EINVAL);
1244 
1245 	result = acpi_start_single_object(device);
1246 	if (!result) {
1247 		memset(&ops, 0, sizeof(ops));
1248 		ops.acpi_op_start = 1;
1249 		result = acpi_bus_scan(device, &ops);
1250 	}
1251 	return_VALUE(result);
1252 }
1253 
1254 EXPORT_SYMBOL(acpi_bus_start);
1255 
1256 int acpi_bus_trim(struct acpi_device *start, int rmdevice)
1257 {
1258 	acpi_status status;
1259 	struct acpi_device *parent, *child;
1260 	acpi_handle phandle, chandle;
1261 	acpi_object_type type;
1262 	u32 level = 1;
1263 	int err = 0;
1264 
1265 	parent = start;
1266 	phandle = start->handle;
1267 	child = chandle = NULL;
1268 
1269 	while ((level > 0) && parent && (!err)) {
1270 		status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
1271 					      chandle, &chandle);
1272 
1273 		/*
1274 		 * If this scope is exhausted then move our way back up.
1275 		 */
1276 		if (ACPI_FAILURE(status)) {
1277 			level--;
1278 			chandle = phandle;
1279 			acpi_get_parent(phandle, &phandle);
1280 			child = parent;
1281 			parent = parent->parent;
1282 
1283 			if (level == 0)
1284 				err = acpi_bus_remove(child, rmdevice);
1285 			else
1286 				err = acpi_bus_remove(child, 1);
1287 
1288 			continue;
1289 		}
1290 
1291 		status = acpi_get_type(chandle, &type);
1292 		if (ACPI_FAILURE(status)) {
1293 			continue;
1294 		}
1295 		/*
1296 		 * If there is a device corresponding to chandle then
1297 		 * parse it (depth-first).
1298 		 */
1299 		if (acpi_bus_get_device(chandle, &child) == 0) {
1300 			level++;
1301 			phandle = chandle;
1302 			chandle = NULL;
1303 			parent = child;
1304 		}
1305 		continue;
1306 	}
1307 	return err;
1308 }
1309 EXPORT_SYMBOL_GPL(acpi_bus_trim);
1310 
1311 
1312 static int acpi_bus_scan_fixed(struct acpi_device *root)
1313 {
1314 	int result = 0;
1315 	struct acpi_device *device = NULL;
1316 
1317 	ACPI_FUNCTION_TRACE("acpi_bus_scan_fixed");
1318 
1319 	if (!root)
1320 		return_VALUE(-ENODEV);
1321 
1322 	/*
1323 	 * Enumerate all fixed-feature devices.
1324 	 */
1325 	if (acpi_fadt.pwr_button == 0) {
1326 		result = acpi_add_single_object(&device, acpi_root,
1327 						NULL,
1328 						ACPI_BUS_TYPE_POWER_BUTTON);
1329 		if (!result)
1330 			result = acpi_start_single_object(device);
1331 	}
1332 
1333 	if (acpi_fadt.sleep_button == 0) {
1334 		result = acpi_add_single_object(&device, acpi_root,
1335 						NULL,
1336 						ACPI_BUS_TYPE_SLEEP_BUTTON);
1337 		if (!result)
1338 			result = acpi_start_single_object(device);
1339 	}
1340 
1341 	return_VALUE(result);
1342 }
1343 
1344 
1345 static inline struct acpi_device * to_acpi_dev(struct device * dev)
1346 {
1347 	return container_of(dev, struct acpi_device, dev);
1348 }
1349 
1350 
1351 static int root_suspend(struct acpi_device * acpi_dev, pm_message_t state)
1352 {
1353 	struct acpi_device * dev, * next;
1354 	int result;
1355 
1356 	spin_lock(&acpi_device_lock);
1357 	list_for_each_entry_safe_reverse(dev, next, &acpi_device_list, g_list) {
1358 		if (dev->driver && dev->driver->ops.suspend) {
1359 			spin_unlock(&acpi_device_lock);
1360 			result = dev->driver->ops.suspend(dev, 0);
1361 			if (result) {
1362 				printk(KERN_ERR PREFIX "[%s - %s] Suspend failed: %d\n",
1363 				       acpi_device_name(dev),
1364 				       acpi_device_bid(dev), result);
1365 			}
1366 			spin_lock(&acpi_device_lock);
1367 		}
1368 	}
1369 	spin_unlock(&acpi_device_lock);
1370 	return 0;
1371 }
1372 
1373 
1374 static int acpi_device_suspend(struct device * dev, pm_message_t state)
1375 {
1376 	struct acpi_device * acpi_dev = to_acpi_dev(dev);
1377 
1378 	/*
1379 	 * For now, we should only register 1 generic device -
1380 	 * the ACPI root device - and from there, we walk the
1381 	 * tree of ACPI devices to suspend each one using the
1382 	 * ACPI driver methods.
1383 	 */
1384 	if (acpi_dev->handle == ACPI_ROOT_OBJECT)
1385 		root_suspend(acpi_dev, state);
1386 	return 0;
1387 }
1388 
1389 
1390 
1391 static int root_resume(struct acpi_device * acpi_dev)
1392 {
1393 	struct acpi_device * dev, * next;
1394 	int result;
1395 
1396 	spin_lock(&acpi_device_lock);
1397 	list_for_each_entry_safe(dev, next, &acpi_device_list, g_list) {
1398 		if (dev->driver && dev->driver->ops.resume) {
1399 			spin_unlock(&acpi_device_lock);
1400 			result = dev->driver->ops.resume(dev, 0);
1401 			if (result) {
1402 				printk(KERN_ERR PREFIX "[%s - %s] resume failed: %d\n",
1403 				       acpi_device_name(dev),
1404 				       acpi_device_bid(dev), result);
1405 			}
1406 			spin_lock(&acpi_device_lock);
1407 		}
1408 	}
1409 	spin_unlock(&acpi_device_lock);
1410 	return 0;
1411 }
1412 
1413 
1414 static int acpi_device_resume(struct device * dev)
1415 {
1416 	struct acpi_device * acpi_dev = to_acpi_dev(dev);
1417 
1418 	/*
1419 	 * For now, we should only register 1 generic device -
1420 	 * the ACPI root device - and from there, we walk the
1421 	 * tree of ACPI devices to resume each one using the
1422 	 * ACPI driver methods.
1423 	 */
1424 	if (acpi_dev->handle == ACPI_ROOT_OBJECT)
1425 		root_resume(acpi_dev);
1426 	return 0;
1427 }
1428 
1429 
1430 struct bus_type acpi_bus_type = {
1431 	.name		= "acpi",
1432 	.suspend	= acpi_device_suspend,
1433 	.resume		= acpi_device_resume,
1434 };
1435 
1436 
1437 
1438 static int __init acpi_scan_init(void)
1439 {
1440 	int result;
1441 	struct acpi_bus_ops ops;
1442 
1443 	ACPI_FUNCTION_TRACE("acpi_scan_init");
1444 
1445 	if (acpi_disabled)
1446 		return_VALUE(0);
1447 
1448 	kset_register(&acpi_namespace_kset);
1449 
1450 	result = bus_register(&acpi_bus_type);
1451 	if (result) {
1452 		/* We don't want to quit even if we failed to add suspend/resume */
1453 		printk(KERN_ERR PREFIX "Could not register bus type\n");
1454 	}
1455 
1456 	/*
1457 	 * Create the root device in the bus's device tree
1458 	 */
1459 	result = acpi_add_single_object(&acpi_root, NULL, ACPI_ROOT_OBJECT,
1460 					ACPI_BUS_TYPE_SYSTEM);
1461 	if (result)
1462 		goto Done;
1463 
1464 	result = acpi_start_single_object(acpi_root);
1465 	if (result)
1466 		goto Done;
1467 
1468 	acpi_root->dev.bus = &acpi_bus_type;
1469 	snprintf(acpi_root->dev.bus_id, BUS_ID_SIZE, "%s", acpi_bus_type.name);
1470 	result = device_register(&acpi_root->dev);
1471 	if (result) {
1472 		/* We don't want to quit even if we failed to add suspend/resume */
1473 		printk(KERN_ERR PREFIX "Could not register device\n");
1474 	}
1475 
1476 	/*
1477 	 * Enumerate devices in the ACPI namespace.
1478 	 */
1479 	result = acpi_bus_scan_fixed(acpi_root);
1480 	if (!result) {
1481 		memset(&ops, 0, sizeof(ops));
1482 		ops.acpi_op_add = 1;
1483 		ops.acpi_op_start = 1;
1484 		result = acpi_bus_scan(acpi_root, &ops);
1485 	}
1486 
1487 	if (result)
1488 		acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);
1489 
1490       Done:
1491 	return_VALUE(result);
1492 }
1493 
1494 subsys_initcall(acpi_scan_init);
1495