1 /*
2  * ACPI PCI HotPlug glue functions to ACPI CA subsystem
3  *
4  * Copyright (C) 2002,2003 Takayoshi Kochi (t-kochi@bq.jp.nec.com)
5  * Copyright (C) 2002 Hiroshi Aono (h-aono@ap.jp.nec.com)
6  * Copyright (C) 2002,2003 NEC Corporation
7  * Copyright (C) 2003-2005 Matthew Wilcox (matthew.wilcox@hp.com)
8  * Copyright (C) 2003-2005 Hewlett Packard
9  * Copyright (C) 2005 Rajesh Shah (rajesh.shah@intel.com)
10  * Copyright (C) 2005 Intel Corporation
11  *
12  * All rights reserved.
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2 of the License, or (at
17  * your option) any later version.
18  *
19  * This program is distributed in the hope that it will be useful, but
20  * WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
22  * NON INFRINGEMENT.  See the GNU General Public License for more
23  * details.
24  *
25  * You should have received a copy of the GNU General Public License
26  * along with this program; if not, write to the Free Software
27  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28  *
29  * Send feedback to <kristen.c.accardi@intel.com>
30  *
31  */
32 
33 /*
34  * Lifetime rules for pci_dev:
35  *  - The one in acpiphp_bridge has its refcount elevated by pci_get_slot()
36  *    when the bridge is scanned and it loses a refcount when the bridge
37  *    is removed.
38  *  - When a P2P bridge is present, we elevate the refcount on the subordinate
39  *    bus. It loses the refcount when the the driver unloads.
40  */
41 
42 #define pr_fmt(fmt) "acpiphp_glue: " fmt
43 
44 #include <linux/module.h>
45 
46 #include <linux/kernel.h>
47 #include <linux/pci.h>
48 #include <linux/pci_hotplug.h>
49 #include <linux/pci-acpi.h>
50 #include <linux/pm_runtime.h>
51 #include <linux/mutex.h>
52 #include <linux/slab.h>
53 #include <linux/acpi.h>
54 
55 #include "../pci.h"
56 #include "acpiphp.h"
57 
58 static LIST_HEAD(bridge_list);
59 static DEFINE_MUTEX(bridge_mutex);
60 
61 static int acpiphp_hotplug_notify(struct acpi_device *adev, u32 type);
62 static void acpiphp_post_dock_fixup(struct acpi_device *adev);
63 static void acpiphp_sanitize_bus(struct pci_bus *bus);
64 static void hotplug_event(u32 type, struct acpiphp_context *context);
65 static void free_bridge(struct kref *kref);
66 
67 /**
68  * acpiphp_init_context - Create hotplug context and grab a reference to it.
69  * @adev: ACPI device object to create the context for.
70  *
71  * Call under acpi_hp_context_lock.
72  */
73 static struct acpiphp_context *acpiphp_init_context(struct acpi_device *adev)
74 {
75 	struct acpiphp_context *context;
76 
77 	context = kzalloc(sizeof(*context), GFP_KERNEL);
78 	if (!context)
79 		return NULL;
80 
81 	context->refcount = 1;
82 	context->hp.notify = acpiphp_hotplug_notify;
83 	context->hp.fixup = acpiphp_post_dock_fixup;
84 	acpi_set_hp_context(adev, &context->hp);
85 	return context;
86 }
87 
88 /**
89  * acpiphp_get_context - Get hotplug context and grab a reference to it.
90  * @adev: ACPI device object to get the context for.
91  *
92  * Call under acpi_hp_context_lock.
93  */
94 static struct acpiphp_context *acpiphp_get_context(struct acpi_device *adev)
95 {
96 	struct acpiphp_context *context;
97 
98 	if (!adev->hp)
99 		return NULL;
100 
101 	context = to_acpiphp_context(adev->hp);
102 	context->refcount++;
103 	return context;
104 }
105 
106 /**
107  * acpiphp_put_context - Drop a reference to ACPI hotplug context.
108  * @context: ACPI hotplug context to drop a reference to.
109  *
110  * The context object is removed if there are no more references to it.
111  *
112  * Call under acpi_hp_context_lock.
113  */
114 static void acpiphp_put_context(struct acpiphp_context *context)
115 {
116 	if (--context->refcount)
117 		return;
118 
119 	WARN_ON(context->bridge);
120 	context->hp.self->hp = NULL;
121 	kfree(context);
122 }
123 
124 static inline void get_bridge(struct acpiphp_bridge *bridge)
125 {
126 	kref_get(&bridge->ref);
127 }
128 
129 static inline void put_bridge(struct acpiphp_bridge *bridge)
130 {
131 	kref_put(&bridge->ref, free_bridge);
132 }
133 
134 static struct acpiphp_context *acpiphp_grab_context(struct acpi_device *adev)
135 {
136 	struct acpiphp_context *context;
137 
138 	acpi_lock_hp_context();
139 	context = acpiphp_get_context(adev);
140 	if (!context || context->func.parent->is_going_away) {
141 		acpi_unlock_hp_context();
142 		return NULL;
143 	}
144 	get_bridge(context->func.parent);
145 	acpiphp_put_context(context);
146 	acpi_unlock_hp_context();
147 	return context;
148 }
149 
150 static void acpiphp_let_context_go(struct acpiphp_context *context)
151 {
152 	put_bridge(context->func.parent);
153 }
154 
155 static void free_bridge(struct kref *kref)
156 {
157 	struct acpiphp_context *context;
158 	struct acpiphp_bridge *bridge;
159 	struct acpiphp_slot *slot, *next;
160 	struct acpiphp_func *func, *tmp;
161 
162 	acpi_lock_hp_context();
163 
164 	bridge = container_of(kref, struct acpiphp_bridge, ref);
165 
166 	list_for_each_entry_safe(slot, next, &bridge->slots, node) {
167 		list_for_each_entry_safe(func, tmp, &slot->funcs, sibling)
168 			acpiphp_put_context(func_to_context(func));
169 
170 		kfree(slot);
171 	}
172 
173 	context = bridge->context;
174 	/* Root bridges will not have hotplug context. */
175 	if (context) {
176 		/* Release the reference taken by acpiphp_enumerate_slots(). */
177 		put_bridge(context->func.parent);
178 		context->bridge = NULL;
179 		acpiphp_put_context(context);
180 	}
181 
182 	put_device(&bridge->pci_bus->dev);
183 	pci_dev_put(bridge->pci_dev);
184 	kfree(bridge);
185 
186 	acpi_unlock_hp_context();
187 }
188 
189 /**
190  * acpiphp_post_dock_fixup - Post-dock fixups for PCI devices.
191  * @adev: ACPI device object corresponding to a PCI device.
192  *
193  * TBD - figure out a way to only call fixups for systems that require them.
194  */
195 static void acpiphp_post_dock_fixup(struct acpi_device *adev)
196 {
197 	struct acpiphp_context *context = acpiphp_grab_context(adev);
198 	struct pci_bus *bus;
199 	u32 buses;
200 
201 	if (!context)
202 		return;
203 
204 	bus = context->func.slot->bus;
205 	if (!bus->self)
206 		goto out;
207 
208 	/* fixup bad _DCK function that rewrites
209 	 * secondary bridge on slot
210 	 */
211 	pci_read_config_dword(bus->self, PCI_PRIMARY_BUS, &buses);
212 
213 	if (((buses >> 8) & 0xff) != bus->busn_res.start) {
214 		buses = (buses & 0xff000000)
215 			| ((unsigned int)(bus->primary)     <<  0)
216 			| ((unsigned int)(bus->busn_res.start)   <<  8)
217 			| ((unsigned int)(bus->busn_res.end) << 16);
218 		pci_write_config_dword(bus->self, PCI_PRIMARY_BUS, buses);
219 	}
220 
221  out:
222 	acpiphp_let_context_go(context);
223 }
224 
225 /* Check whether the PCI device is managed by native PCIe hotplug driver */
226 static bool device_is_managed_by_native_pciehp(struct pci_dev *pdev)
227 {
228 	u32 reg32;
229 	acpi_handle tmp;
230 	struct acpi_pci_root *root;
231 
232 	/* Check whether the PCIe port supports native PCIe hotplug */
233 	if (pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &reg32))
234 		return false;
235 	if (!(reg32 & PCI_EXP_SLTCAP_HPC))
236 		return false;
237 
238 	/*
239 	 * Check whether native PCIe hotplug has been enabled for
240 	 * this PCIe hierarchy.
241 	 */
242 	tmp = acpi_find_root_bridge_handle(pdev);
243 	if (!tmp)
244 		return false;
245 	root = acpi_pci_find_root(tmp);
246 	if (!root)
247 		return false;
248 	if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
249 		return false;
250 
251 	return true;
252 }
253 
254 /**
255  * acpiphp_add_context - Add ACPIPHP context to an ACPI device object.
256  * @handle: ACPI handle of the object to add a context to.
257  * @lvl: Not used.
258  * @data: The object's parent ACPIPHP bridge.
259  * @rv: Not used.
260  */
261 static acpi_status acpiphp_add_context(acpi_handle handle, u32 lvl, void *data,
262 				       void **rv)
263 {
264 	struct acpiphp_bridge *bridge = data;
265 	struct acpiphp_context *context;
266 	struct acpi_device *adev;
267 	struct acpiphp_slot *slot;
268 	struct acpiphp_func *newfunc;
269 	acpi_status status = AE_OK;
270 	unsigned long long adr;
271 	int device, function;
272 	struct pci_bus *pbus = bridge->pci_bus;
273 	struct pci_dev *pdev = bridge->pci_dev;
274 	u32 val;
275 
276 	status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
277 	if (ACPI_FAILURE(status)) {
278 		if (status != AE_NOT_FOUND)
279 			acpi_handle_warn(handle,
280 				"can't evaluate _ADR (%#x)\n", status);
281 		return AE_OK;
282 	}
283 	if (acpi_bus_get_device(handle, &adev))
284 		return AE_OK;
285 
286 	device = (adr >> 16) & 0xffff;
287 	function = adr & 0xffff;
288 
289 	acpi_lock_hp_context();
290 	context = acpiphp_init_context(adev);
291 	if (!context) {
292 		acpi_unlock_hp_context();
293 		acpi_handle_err(handle, "No hotplug context\n");
294 		return AE_NOT_EXIST;
295 	}
296 	newfunc = &context->func;
297 	newfunc->function = function;
298 	newfunc->parent = bridge;
299 	acpi_unlock_hp_context();
300 
301 	/*
302 	 * If this is a dock device, its _EJ0 should be executed by the dock
303 	 * notify handler after calling _DCK.
304 	 */
305 	if (!is_dock_device(adev) && acpi_has_method(handle, "_EJ0"))
306 		newfunc->flags = FUNC_HAS_EJ0;
307 
308 	if (acpi_has_method(handle, "_STA"))
309 		newfunc->flags |= FUNC_HAS_STA;
310 
311 	/* search for objects that share the same slot */
312 	list_for_each_entry(slot, &bridge->slots, node)
313 		if (slot->device == device)
314 			goto slot_found;
315 
316 	slot = kzalloc(sizeof(struct acpiphp_slot), GFP_KERNEL);
317 	if (!slot) {
318 		acpi_lock_hp_context();
319 		acpiphp_put_context(context);
320 		acpi_unlock_hp_context();
321 		return AE_NO_MEMORY;
322 	}
323 
324 	slot->bus = bridge->pci_bus;
325 	slot->device = device;
326 	INIT_LIST_HEAD(&slot->funcs);
327 
328 	list_add_tail(&slot->node, &bridge->slots);
329 
330 	/*
331 	 * Expose slots to user space for functions that have _EJ0 or _RMV or
332 	 * are located in dock stations.  Do not expose them for devices handled
333 	 * by the native PCIe hotplug (PCIeHP), becuase that code is supposed to
334 	 * expose slots to user space in those cases.
335 	 */
336 	if ((acpi_pci_check_ejectable(pbus, handle) || is_dock_device(adev))
337 	    && !(pdev && device_is_managed_by_native_pciehp(pdev))) {
338 		unsigned long long sun;
339 		int retval;
340 
341 		bridge->nr_slots++;
342 		status = acpi_evaluate_integer(handle, "_SUN", NULL, &sun);
343 		if (ACPI_FAILURE(status))
344 			sun = bridge->nr_slots;
345 
346 		pr_debug("found ACPI PCI Hotplug slot %llu at PCI %04x:%02x:%02x\n",
347 		    sun, pci_domain_nr(pbus), pbus->number, device);
348 
349 		retval = acpiphp_register_hotplug_slot(slot, sun);
350 		if (retval) {
351 			slot->slot = NULL;
352 			bridge->nr_slots--;
353 			if (retval == -EBUSY)
354 				pr_warn("Slot %llu already registered by another hotplug driver\n", sun);
355 			else
356 				pr_warn("acpiphp_register_hotplug_slot failed (err code = 0x%x)\n", retval);
357 		}
358 		/* Even if the slot registration fails, we can still use it. */
359 	}
360 
361  slot_found:
362 	newfunc->slot = slot;
363 	list_add_tail(&newfunc->sibling, &slot->funcs);
364 
365 	if (pci_bus_read_dev_vendor_id(pbus, PCI_DEVFN(device, function),
366 				       &val, 60*1000))
367 		slot->flags |= SLOT_ENABLED;
368 
369 	return AE_OK;
370 }
371 
372 static void cleanup_bridge(struct acpiphp_bridge *bridge)
373 {
374 	struct acpiphp_slot *slot;
375 	struct acpiphp_func *func;
376 
377 	list_for_each_entry(slot, &bridge->slots, node) {
378 		list_for_each_entry(func, &slot->funcs, sibling) {
379 			struct acpi_device *adev = func_to_acpi_device(func);
380 
381 			acpi_lock_hp_context();
382 			adev->hp->notify = NULL;
383 			adev->hp->fixup = NULL;
384 			acpi_unlock_hp_context();
385 		}
386 		slot->flags |= SLOT_IS_GOING_AWAY;
387 		if (slot->slot)
388 			acpiphp_unregister_hotplug_slot(slot);
389 	}
390 
391 	mutex_lock(&bridge_mutex);
392 	list_del(&bridge->list);
393 	mutex_unlock(&bridge_mutex);
394 
395 	acpi_lock_hp_context();
396 	bridge->is_going_away = true;
397 	acpi_unlock_hp_context();
398 }
399 
400 /**
401  * acpiphp_max_busnr - return the highest reserved bus number under the given bus.
402  * @bus: bus to start search with
403  */
404 static unsigned char acpiphp_max_busnr(struct pci_bus *bus)
405 {
406 	struct pci_bus *tmp;
407 	unsigned char max, n;
408 
409 	/*
410 	 * pci_bus_max_busnr will return the highest
411 	 * reserved busnr for all these children.
412 	 * that is equivalent to the bus->subordinate
413 	 * value.  We don't want to use the parent's
414 	 * bus->subordinate value because it could have
415 	 * padding in it.
416 	 */
417 	max = bus->busn_res.start;
418 
419 	list_for_each_entry(tmp, &bus->children, node) {
420 		n = pci_bus_max_busnr(tmp);
421 		if (n > max)
422 			max = n;
423 	}
424 	return max;
425 }
426 
427 static void acpiphp_set_acpi_region(struct acpiphp_slot *slot)
428 {
429 	struct acpiphp_func *func;
430 	union acpi_object params[2];
431 	struct acpi_object_list arg_list;
432 
433 	list_for_each_entry(func, &slot->funcs, sibling) {
434 		arg_list.count = 2;
435 		arg_list.pointer = params;
436 		params[0].type = ACPI_TYPE_INTEGER;
437 		params[0].integer.value = ACPI_ADR_SPACE_PCI_CONFIG;
438 		params[1].type = ACPI_TYPE_INTEGER;
439 		params[1].integer.value = 1;
440 		/* _REG is optional, we don't care about if there is failure */
441 		acpi_evaluate_object(func_to_handle(func), "_REG", &arg_list,
442 				     NULL);
443 	}
444 }
445 
446 static void check_hotplug_bridge(struct acpiphp_slot *slot, struct pci_dev *dev)
447 {
448 	struct acpiphp_func *func;
449 
450 	/* quirk, or pcie could set it already */
451 	if (dev->is_hotplug_bridge)
452 		return;
453 
454 	list_for_each_entry(func, &slot->funcs, sibling) {
455 		if (PCI_FUNC(dev->devfn) == func->function) {
456 			dev->is_hotplug_bridge = 1;
457 			break;
458 		}
459 	}
460 }
461 
462 static int acpiphp_rescan_slot(struct acpiphp_slot *slot)
463 {
464 	struct acpiphp_func *func;
465 
466 	list_for_each_entry(func, &slot->funcs, sibling) {
467 		struct acpi_device *adev = func_to_acpi_device(func);
468 
469 		acpi_bus_scan(adev->handle);
470 		if (acpi_device_enumerated(adev))
471 			acpi_device_set_power(adev, ACPI_STATE_D0);
472 	}
473 	return pci_scan_slot(slot->bus, PCI_DEVFN(slot->device, 0));
474 }
475 
476 /**
477  * enable_slot - enable, configure a slot
478  * @slot: slot to be enabled
479  *
480  * This function should be called per *physical slot*,
481  * not per each slot object in ACPI namespace.
482  */
483 static void enable_slot(struct acpiphp_slot *slot)
484 {
485 	struct pci_dev *dev;
486 	struct pci_bus *bus = slot->bus;
487 	struct acpiphp_func *func;
488 	int max, pass;
489 	LIST_HEAD(add_list);
490 
491 	acpiphp_rescan_slot(slot);
492 	max = acpiphp_max_busnr(bus);
493 	for (pass = 0; pass < 2; pass++) {
494 		list_for_each_entry(dev, &bus->devices, bus_list) {
495 			if (PCI_SLOT(dev->devfn) != slot->device)
496 				continue;
497 
498 			if (pci_is_bridge(dev)) {
499 				max = pci_scan_bridge(bus, dev, max, pass);
500 				if (pass && dev->subordinate) {
501 					check_hotplug_bridge(slot, dev);
502 					pcibios_resource_survey_bus(dev->subordinate);
503 					__pci_bus_size_bridges(dev->subordinate,
504 							       &add_list);
505 				}
506 			}
507 		}
508 	}
509 	__pci_bus_assign_resources(bus, &add_list, NULL);
510 
511 	acpiphp_sanitize_bus(bus);
512 	pcie_bus_configure_settings(bus);
513 	acpiphp_set_acpi_region(slot);
514 
515 	list_for_each_entry(dev, &bus->devices, bus_list) {
516 		/* Assume that newly added devices are powered on already. */
517 		if (!dev->is_added)
518 			dev->current_state = PCI_D0;
519 	}
520 
521 	pci_bus_add_devices(bus);
522 
523 	slot->flags |= SLOT_ENABLED;
524 	list_for_each_entry(func, &slot->funcs, sibling) {
525 		dev = pci_get_slot(bus, PCI_DEVFN(slot->device,
526 						  func->function));
527 		if (!dev) {
528 			/* Do not set SLOT_ENABLED flag if some funcs
529 			   are not added. */
530 			slot->flags &= (~SLOT_ENABLED);
531 			continue;
532 		}
533 	}
534 }
535 
536 /**
537  * disable_slot - disable a slot
538  * @slot: ACPI PHP slot
539  */
540 static void disable_slot(struct acpiphp_slot *slot)
541 {
542 	struct pci_bus *bus = slot->bus;
543 	struct pci_dev *dev, *prev;
544 	struct acpiphp_func *func;
545 
546 	/*
547 	 * enable_slot() enumerates all functions in this device via
548 	 * pci_scan_slot(), whether they have associated ACPI hotplug
549 	 * methods (_EJ0, etc.) or not.  Therefore, we remove all functions
550 	 * here.
551 	 */
552 	list_for_each_entry_safe_reverse(dev, prev, &bus->devices, bus_list)
553 		if (PCI_SLOT(dev->devfn) == slot->device)
554 			pci_stop_and_remove_bus_device(dev);
555 
556 	list_for_each_entry(func, &slot->funcs, sibling)
557 		acpi_bus_trim(func_to_acpi_device(func));
558 
559 	slot->flags &= (~SLOT_ENABLED);
560 }
561 
562 static bool slot_no_hotplug(struct acpiphp_slot *slot)
563 {
564 	struct pci_bus *bus = slot->bus;
565 	struct pci_dev *dev;
566 
567 	list_for_each_entry(dev, &bus->devices, bus_list) {
568 		if (PCI_SLOT(dev->devfn) == slot->device && dev->ignore_hotplug)
569 			return true;
570 	}
571 	return false;
572 }
573 
574 /**
575  * get_slot_status - get ACPI slot status
576  * @slot: ACPI PHP slot
577  *
578  * If a slot has _STA for each function and if any one of them
579  * returned non-zero status, return it.
580  *
581  * If a slot doesn't have _STA and if any one of its functions'
582  * configuration space is configured, return 0x0f as a _STA.
583  *
584  * Otherwise return 0.
585  */
586 static unsigned int get_slot_status(struct acpiphp_slot *slot)
587 {
588 	unsigned long long sta = 0;
589 	struct acpiphp_func *func;
590 
591 	list_for_each_entry(func, &slot->funcs, sibling) {
592 		if (func->flags & FUNC_HAS_STA) {
593 			acpi_status status;
594 
595 			status = acpi_evaluate_integer(func_to_handle(func),
596 						       "_STA", NULL, &sta);
597 			if (ACPI_SUCCESS(status) && sta)
598 				break;
599 		} else {
600 			u32 dvid;
601 
602 			pci_bus_read_config_dword(slot->bus,
603 						  PCI_DEVFN(slot->device,
604 							    func->function),
605 						  PCI_VENDOR_ID, &dvid);
606 			if (dvid != 0xffffffff) {
607 				sta = ACPI_STA_ALL;
608 				break;
609 			}
610 		}
611 	}
612 
613 	return (unsigned int)sta;
614 }
615 
616 static inline bool device_status_valid(unsigned int sta)
617 {
618 	/*
619 	 * ACPI spec says that _STA may return bit 0 clear with bit 3 set
620 	 * if the device is valid but does not require a device driver to be
621 	 * loaded (Section 6.3.7 of ACPI 5.0A).
622 	 */
623 	unsigned int mask = ACPI_STA_DEVICE_ENABLED | ACPI_STA_DEVICE_FUNCTIONING;
624 	return (sta & mask) == mask;
625 }
626 
627 /**
628  * trim_stale_devices - remove PCI devices that are not responding.
629  * @dev: PCI device to start walking the hierarchy from.
630  */
631 static void trim_stale_devices(struct pci_dev *dev)
632 {
633 	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
634 	struct pci_bus *bus = dev->subordinate;
635 	bool alive = dev->ignore_hotplug;
636 
637 	if (adev) {
638 		acpi_status status;
639 		unsigned long long sta;
640 
641 		status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
642 		alive = alive || (ACPI_SUCCESS(status) && device_status_valid(sta));
643 	}
644 	if (!alive)
645 		alive = pci_device_is_present(dev);
646 
647 	if (!alive) {
648 		pci_stop_and_remove_bus_device(dev);
649 		if (adev)
650 			acpi_bus_trim(adev);
651 	} else if (bus) {
652 		struct pci_dev *child, *tmp;
653 
654 		/* The device is a bridge. so check the bus below it. */
655 		pm_runtime_get_sync(&dev->dev);
656 		list_for_each_entry_safe_reverse(child, tmp, &bus->devices, bus_list)
657 			trim_stale_devices(child);
658 
659 		pm_runtime_put(&dev->dev);
660 	}
661 }
662 
663 /**
664  * acpiphp_check_bridge - re-enumerate devices
665  * @bridge: where to begin re-enumeration
666  *
667  * Iterate over all slots under this bridge and make sure that if a
668  * card is present they are enabled, and if not they are disabled.
669  */
670 static void acpiphp_check_bridge(struct acpiphp_bridge *bridge)
671 {
672 	struct acpiphp_slot *slot;
673 
674 	/* Bail out if the bridge is going away. */
675 	if (bridge->is_going_away)
676 		return;
677 
678 	list_for_each_entry(slot, &bridge->slots, node) {
679 		struct pci_bus *bus = slot->bus;
680 		struct pci_dev *dev, *tmp;
681 
682 		if (slot_no_hotplug(slot)) {
683 			; /* do nothing */
684 		} else if (device_status_valid(get_slot_status(slot))) {
685 			/* remove stale devices if any */
686 			list_for_each_entry_safe_reverse(dev, tmp,
687 							 &bus->devices, bus_list)
688 				if (PCI_SLOT(dev->devfn) == slot->device)
689 					trim_stale_devices(dev);
690 
691 			/* configure all functions */
692 			enable_slot(slot);
693 		} else {
694 			disable_slot(slot);
695 		}
696 	}
697 }
698 
699 /*
700  * Remove devices for which we could not assign resources, call
701  * arch specific code to fix-up the bus
702  */
703 static void acpiphp_sanitize_bus(struct pci_bus *bus)
704 {
705 	struct pci_dev *dev, *tmp;
706 	int i;
707 	unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM;
708 
709 	list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) {
710 		for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) {
711 			struct resource *res = &dev->resource[i];
712 			if ((res->flags & type_mask) && !res->start &&
713 					res->end) {
714 				/* Could not assign a required resources
715 				 * for this device, remove it */
716 				pci_stop_and_remove_bus_device(dev);
717 				break;
718 			}
719 		}
720 	}
721 }
722 
723 /*
724  * ACPI event handlers
725  */
726 
727 void acpiphp_check_host_bridge(struct acpi_device *adev)
728 {
729 	struct acpiphp_bridge *bridge = NULL;
730 
731 	acpi_lock_hp_context();
732 	if (adev->hp) {
733 		bridge = to_acpiphp_root_context(adev->hp)->root_bridge;
734 		if (bridge)
735 			get_bridge(bridge);
736 	}
737 	acpi_unlock_hp_context();
738 	if (bridge) {
739 		pci_lock_rescan_remove();
740 
741 		acpiphp_check_bridge(bridge);
742 
743 		pci_unlock_rescan_remove();
744 		put_bridge(bridge);
745 	}
746 }
747 
748 static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot);
749 
750 static void hotplug_event(u32 type, struct acpiphp_context *context)
751 {
752 	acpi_handle handle = context->hp.self->handle;
753 	struct acpiphp_func *func = &context->func;
754 	struct acpiphp_slot *slot = func->slot;
755 	struct acpiphp_bridge *bridge;
756 
757 	acpi_lock_hp_context();
758 	bridge = context->bridge;
759 	if (bridge)
760 		get_bridge(bridge);
761 
762 	acpi_unlock_hp_context();
763 
764 	pci_lock_rescan_remove();
765 
766 	switch (type) {
767 	case ACPI_NOTIFY_BUS_CHECK:
768 		/* bus re-enumerate */
769 		acpi_handle_debug(handle, "Bus check in %s()\n", __func__);
770 		if (bridge)
771 			acpiphp_check_bridge(bridge);
772 		else if (!(slot->flags & SLOT_IS_GOING_AWAY))
773 			enable_slot(slot);
774 
775 		break;
776 
777 	case ACPI_NOTIFY_DEVICE_CHECK:
778 		/* device check */
779 		acpi_handle_debug(handle, "Device check in %s()\n", __func__);
780 		if (bridge) {
781 			acpiphp_check_bridge(bridge);
782 		} else if (!(slot->flags & SLOT_IS_GOING_AWAY)) {
783 			/*
784 			 * Check if anything has changed in the slot and rescan
785 			 * from the parent if that's the case.
786 			 */
787 			if (acpiphp_rescan_slot(slot))
788 				acpiphp_check_bridge(func->parent);
789 		}
790 		break;
791 
792 	case ACPI_NOTIFY_EJECT_REQUEST:
793 		/* request device eject */
794 		acpi_handle_debug(handle, "Eject request in %s()\n", __func__);
795 		acpiphp_disable_and_eject_slot(slot);
796 		break;
797 	}
798 
799 	pci_unlock_rescan_remove();
800 	if (bridge)
801 		put_bridge(bridge);
802 }
803 
804 static int acpiphp_hotplug_notify(struct acpi_device *adev, u32 type)
805 {
806 	struct acpiphp_context *context;
807 
808 	context = acpiphp_grab_context(adev);
809 	if (!context)
810 		return -ENODATA;
811 
812 	hotplug_event(type, context);
813 	acpiphp_let_context_go(context);
814 	return 0;
815 }
816 
817 /**
818  * acpiphp_enumerate_slots - Enumerate PCI slots for a given bus.
819  * @bus: PCI bus to enumerate the slots for.
820  *
821  * A "slot" is an object associated with a PCI device number.  All functions
822  * (PCI devices) with the same bus and device number belong to the same slot.
823  */
824 void acpiphp_enumerate_slots(struct pci_bus *bus)
825 {
826 	struct acpiphp_bridge *bridge;
827 	struct acpi_device *adev;
828 	acpi_handle handle;
829 	acpi_status status;
830 
831 	if (acpiphp_disabled)
832 		return;
833 
834 	adev = ACPI_COMPANION(bus->bridge);
835 	if (!adev)
836 		return;
837 
838 	handle = adev->handle;
839 	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
840 	if (!bridge) {
841 		acpi_handle_err(handle, "No memory for bridge object\n");
842 		return;
843 	}
844 
845 	INIT_LIST_HEAD(&bridge->slots);
846 	kref_init(&bridge->ref);
847 	bridge->pci_dev = pci_dev_get(bus->self);
848 	bridge->pci_bus = bus;
849 
850 	/*
851 	 * Grab a ref to the subordinate PCI bus in case the bus is
852 	 * removed via PCI core logical hotplug. The ref pins the bus
853 	 * (which we access during module unload).
854 	 */
855 	get_device(&bus->dev);
856 
857 	acpi_lock_hp_context();
858 	if (pci_is_root_bus(bridge->pci_bus)) {
859 		struct acpiphp_root_context *root_context;
860 
861 		root_context = kzalloc(sizeof(*root_context), GFP_KERNEL);
862 		if (!root_context)
863 			goto err;
864 
865 		root_context->root_bridge = bridge;
866 		acpi_set_hp_context(adev, &root_context->hp);
867 	} else {
868 		struct acpiphp_context *context;
869 
870 		/*
871 		 * This bridge should have been registered as a hotplug function
872 		 * under its parent, so the context should be there, unless the
873 		 * parent is going to be handled by pciehp, in which case this
874 		 * bridge is not interesting to us either.
875 		 */
876 		context = acpiphp_get_context(adev);
877 		if (!context)
878 			goto err;
879 
880 		bridge->context = context;
881 		context->bridge = bridge;
882 		/* Get a reference to the parent bridge. */
883 		get_bridge(context->func.parent);
884 	}
885 	acpi_unlock_hp_context();
886 
887 	/* Must be added to the list prior to calling acpiphp_add_context(). */
888 	mutex_lock(&bridge_mutex);
889 	list_add(&bridge->list, &bridge_list);
890 	mutex_unlock(&bridge_mutex);
891 
892 	/* register all slot objects under this bridge */
893 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
894 				     acpiphp_add_context, NULL, bridge, NULL);
895 	if (ACPI_FAILURE(status)) {
896 		acpi_handle_err(handle, "failed to register slots\n");
897 		cleanup_bridge(bridge);
898 		put_bridge(bridge);
899 	}
900 	return;
901 
902  err:
903 	acpi_unlock_hp_context();
904 	put_device(&bus->dev);
905 	pci_dev_put(bridge->pci_dev);
906 	kfree(bridge);
907 }
908 
909 static void acpiphp_drop_bridge(struct acpiphp_bridge *bridge)
910 {
911 	if (pci_is_root_bus(bridge->pci_bus)) {
912 		struct acpiphp_root_context *root_context;
913 		struct acpi_device *adev;
914 
915 		acpi_lock_hp_context();
916 		adev = ACPI_COMPANION(bridge->pci_bus->bridge);
917 		root_context = to_acpiphp_root_context(adev->hp);
918 		adev->hp = NULL;
919 		acpi_unlock_hp_context();
920 		kfree(root_context);
921 	}
922 	cleanup_bridge(bridge);
923 	put_bridge(bridge);
924 }
925 
926 /**
927  * acpiphp_remove_slots - Remove slot objects associated with a given bus.
928  * @bus: PCI bus to remove the slot objects for.
929  */
930 void acpiphp_remove_slots(struct pci_bus *bus)
931 {
932 	struct acpiphp_bridge *bridge;
933 
934 	if (acpiphp_disabled)
935 		return;
936 
937 	mutex_lock(&bridge_mutex);
938 	list_for_each_entry(bridge, &bridge_list, list)
939 		if (bridge->pci_bus == bus) {
940 			mutex_unlock(&bridge_mutex);
941 			acpiphp_drop_bridge(bridge);
942 			return;
943 		}
944 
945 	mutex_unlock(&bridge_mutex);
946 }
947 
948 /**
949  * acpiphp_enable_slot - power on slot
950  * @slot: ACPI PHP slot
951  */
952 int acpiphp_enable_slot(struct acpiphp_slot *slot)
953 {
954 	pci_lock_rescan_remove();
955 
956 	if (slot->flags & SLOT_IS_GOING_AWAY) {
957 		pci_unlock_rescan_remove();
958 		return -ENODEV;
959 	}
960 
961 	/* configure all functions */
962 	if (!(slot->flags & SLOT_ENABLED))
963 		enable_slot(slot);
964 
965 	pci_unlock_rescan_remove();
966 	return 0;
967 }
968 
969 /**
970  * acpiphp_disable_and_eject_slot - power off and eject slot
971  * @slot: ACPI PHP slot
972  */
973 static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot)
974 {
975 	struct acpiphp_func *func;
976 
977 	if (slot->flags & SLOT_IS_GOING_AWAY)
978 		return -ENODEV;
979 
980 	/* unconfigure all functions */
981 	disable_slot(slot);
982 
983 	list_for_each_entry(func, &slot->funcs, sibling)
984 		if (func->flags & FUNC_HAS_EJ0) {
985 			acpi_handle handle = func_to_handle(func);
986 
987 			if (ACPI_FAILURE(acpi_evaluate_ej0(handle)))
988 				acpi_handle_err(handle, "_EJ0 failed\n");
989 
990 			break;
991 		}
992 
993 	return 0;
994 }
995 
996 int acpiphp_disable_slot(struct acpiphp_slot *slot)
997 {
998 	int ret;
999 
1000 	/*
1001 	 * Acquire acpi_scan_lock to ensure that the execution of _EJ0 in
1002 	 * acpiphp_disable_and_eject_slot() will be synchronized properly.
1003 	 */
1004 	acpi_scan_lock_acquire();
1005 	pci_lock_rescan_remove();
1006 	ret = acpiphp_disable_and_eject_slot(slot);
1007 	pci_unlock_rescan_remove();
1008 	acpi_scan_lock_release();
1009 	return ret;
1010 }
1011 
1012 /*
1013  * slot enabled:  1
1014  * slot disabled: 0
1015  */
1016 u8 acpiphp_get_power_status(struct acpiphp_slot *slot)
1017 {
1018 	return (slot->flags & SLOT_ENABLED);
1019 }
1020 
1021 /*
1022  * latch   open:  1
1023  * latch closed:  0
1024  */
1025 u8 acpiphp_get_latch_status(struct acpiphp_slot *slot)
1026 {
1027 	return !(get_slot_status(slot) & ACPI_STA_DEVICE_UI);
1028 }
1029 
1030 /*
1031  * adapter presence : 1
1032  *          absence : 0
1033  */
1034 u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot)
1035 {
1036 	return !!get_slot_status(slot);
1037 }
1038