1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * ACPI PCI HotPlug glue functions to ACPI CA subsystem
4  *
5  * Copyright (C) 2002,2003 Takayoshi Kochi (t-kochi@bq.jp.nec.com)
6  * Copyright (C) 2002 Hiroshi Aono (h-aono@ap.jp.nec.com)
7  * Copyright (C) 2002,2003 NEC Corporation
8  * Copyright (C) 2003-2005 Matthew Wilcox (willy@infradead.org)
9  * Copyright (C) 2003-2005 Hewlett Packard
10  * Copyright (C) 2005 Rajesh Shah (rajesh.shah@intel.com)
11  * Copyright (C) 2005 Intel Corporation
12  *
13  * All rights reserved.
14  *
15  * Send feedback to <kristen.c.accardi@intel.com>
16  *
17  */
18 
19 /*
20  * Lifetime rules for pci_dev:
21  *  - The one in acpiphp_bridge has its refcount elevated by pci_get_slot()
22  *    when the bridge is scanned and it loses a refcount when the bridge
23  *    is removed.
24  *  - When a P2P bridge is present, we elevate the refcount on the subordinate
25  *    bus. It loses the refcount when the driver unloads.
26  */
27 
28 #define pr_fmt(fmt) "acpiphp_glue: " fmt
29 
30 #include <linux/module.h>
31 
32 #include <linux/kernel.h>
33 #include <linux/pci.h>
34 #include <linux/pci_hotplug.h>
35 #include <linux/pci-acpi.h>
36 #include <linux/pm_runtime.h>
37 #include <linux/mutex.h>
38 #include <linux/slab.h>
39 #include <linux/acpi.h>
40 
41 #include "../pci.h"
42 #include "acpiphp.h"
43 
44 static LIST_HEAD(bridge_list);
45 static DEFINE_MUTEX(bridge_mutex);
46 
47 static int acpiphp_hotplug_notify(struct acpi_device *adev, u32 type);
48 static void acpiphp_post_dock_fixup(struct acpi_device *adev);
49 static void acpiphp_sanitize_bus(struct pci_bus *bus);
50 static void hotplug_event(u32 type, struct acpiphp_context *context);
51 static void free_bridge(struct kref *kref);
52 
53 /**
54  * acpiphp_init_context - Create hotplug context and grab a reference to it.
55  * @adev: ACPI device object to create the context for.
56  *
57  * Call under acpi_hp_context_lock.
58  */
59 static struct acpiphp_context *acpiphp_init_context(struct acpi_device *adev)
60 {
61 	struct acpiphp_context *context;
62 
63 	context = kzalloc(sizeof(*context), GFP_KERNEL);
64 	if (!context)
65 		return NULL;
66 
67 	context->refcount = 1;
68 	context->hp.notify = acpiphp_hotplug_notify;
69 	context->hp.fixup = acpiphp_post_dock_fixup;
70 	acpi_set_hp_context(adev, &context->hp);
71 	return context;
72 }
73 
74 /**
75  * acpiphp_get_context - Get hotplug context and grab a reference to it.
76  * @adev: ACPI device object to get the context for.
77  *
78  * Call under acpi_hp_context_lock.
79  */
80 static struct acpiphp_context *acpiphp_get_context(struct acpi_device *adev)
81 {
82 	struct acpiphp_context *context;
83 
84 	if (!adev->hp)
85 		return NULL;
86 
87 	context = to_acpiphp_context(adev->hp);
88 	context->refcount++;
89 	return context;
90 }
91 
92 /**
93  * acpiphp_put_context - Drop a reference to ACPI hotplug context.
94  * @context: ACPI hotplug context to drop a reference to.
95  *
96  * The context object is removed if there are no more references to it.
97  *
98  * Call under acpi_hp_context_lock.
99  */
100 static void acpiphp_put_context(struct acpiphp_context *context)
101 {
102 	if (--context->refcount)
103 		return;
104 
105 	WARN_ON(context->bridge);
106 	context->hp.self->hp = NULL;
107 	kfree(context);
108 }
109 
110 static inline void get_bridge(struct acpiphp_bridge *bridge)
111 {
112 	kref_get(&bridge->ref);
113 }
114 
115 static inline void put_bridge(struct acpiphp_bridge *bridge)
116 {
117 	kref_put(&bridge->ref, free_bridge);
118 }
119 
120 static struct acpiphp_context *acpiphp_grab_context(struct acpi_device *adev)
121 {
122 	struct acpiphp_context *context;
123 
124 	acpi_lock_hp_context();
125 
126 	context = acpiphp_get_context(adev);
127 	if (!context)
128 		goto unlock;
129 
130 	if (context->func.parent->is_going_away) {
131 		acpiphp_put_context(context);
132 		context = NULL;
133 		goto unlock;
134 	}
135 
136 	get_bridge(context->func.parent);
137 	acpiphp_put_context(context);
138 
139 unlock:
140 	acpi_unlock_hp_context();
141 	return context;
142 }
143 
144 static void acpiphp_let_context_go(struct acpiphp_context *context)
145 {
146 	put_bridge(context->func.parent);
147 }
148 
149 static void free_bridge(struct kref *kref)
150 {
151 	struct acpiphp_context *context;
152 	struct acpiphp_bridge *bridge;
153 	struct acpiphp_slot *slot, *next;
154 	struct acpiphp_func *func, *tmp;
155 
156 	acpi_lock_hp_context();
157 
158 	bridge = container_of(kref, struct acpiphp_bridge, ref);
159 
160 	list_for_each_entry_safe(slot, next, &bridge->slots, node) {
161 		list_for_each_entry_safe(func, tmp, &slot->funcs, sibling)
162 			acpiphp_put_context(func_to_context(func));
163 
164 		kfree(slot);
165 	}
166 
167 	context = bridge->context;
168 	/* Root bridges will not have hotplug context. */
169 	if (context) {
170 		/* Release the reference taken by acpiphp_enumerate_slots(). */
171 		put_bridge(context->func.parent);
172 		context->bridge = NULL;
173 		acpiphp_put_context(context);
174 	}
175 
176 	put_device(&bridge->pci_bus->dev);
177 	pci_dev_put(bridge->pci_dev);
178 	kfree(bridge);
179 
180 	acpi_unlock_hp_context();
181 }
182 
183 /**
184  * acpiphp_post_dock_fixup - Post-dock fixups for PCI devices.
185  * @adev: ACPI device object corresponding to a PCI device.
186  *
187  * TBD - figure out a way to only call fixups for systems that require them.
188  */
189 static void acpiphp_post_dock_fixup(struct acpi_device *adev)
190 {
191 	struct acpiphp_context *context = acpiphp_grab_context(adev);
192 	struct pci_bus *bus;
193 	u32 buses;
194 
195 	if (!context)
196 		return;
197 
198 	bus = context->func.slot->bus;
199 	if (!bus->self)
200 		goto out;
201 
202 	/* fixup bad _DCK function that rewrites
203 	 * secondary bridge on slot
204 	 */
205 	pci_read_config_dword(bus->self, PCI_PRIMARY_BUS, &buses);
206 
207 	if (((buses >> 8) & 0xff) != bus->busn_res.start) {
208 		buses = (buses & 0xff000000)
209 			| ((unsigned int)(bus->primary)     <<  0)
210 			| ((unsigned int)(bus->busn_res.start)   <<  8)
211 			| ((unsigned int)(bus->busn_res.end) << 16);
212 		pci_write_config_dword(bus->self, PCI_PRIMARY_BUS, buses);
213 	}
214 
215  out:
216 	acpiphp_let_context_go(context);
217 }
218 
219 /**
220  * acpiphp_add_context - Add ACPIPHP context to an ACPI device object.
221  * @handle: ACPI handle of the object to add a context to.
222  * @lvl: Not used.
223  * @data: The object's parent ACPIPHP bridge.
224  * @rv: Not used.
225  */
226 static acpi_status acpiphp_add_context(acpi_handle handle, u32 lvl, void *data,
227 				       void **rv)
228 {
229 	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
230 	struct acpiphp_bridge *bridge = data;
231 	struct acpiphp_context *context;
232 	struct acpiphp_slot *slot;
233 	struct acpiphp_func *newfunc;
234 	acpi_status status = AE_OK;
235 	unsigned long long adr;
236 	int device, function;
237 	struct pci_bus *pbus = bridge->pci_bus;
238 	struct pci_dev *pdev = bridge->pci_dev;
239 	u32 val;
240 
241 	if (!adev)
242 		return AE_OK;
243 
244 	status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
245 	if (ACPI_FAILURE(status)) {
246 		if (status != AE_NOT_FOUND)
247 			acpi_handle_warn(handle,
248 				"can't evaluate _ADR (%#x)\n", status);
249 		return AE_OK;
250 	}
251 
252 	device = (adr >> 16) & 0xffff;
253 	function = adr & 0xffff;
254 
255 	acpi_lock_hp_context();
256 	context = acpiphp_init_context(adev);
257 	if (!context) {
258 		acpi_unlock_hp_context();
259 		acpi_handle_err(handle, "No hotplug context\n");
260 		return AE_NOT_EXIST;
261 	}
262 	newfunc = &context->func;
263 	newfunc->function = function;
264 	newfunc->parent = bridge;
265 	acpi_unlock_hp_context();
266 
267 	/*
268 	 * If this is a dock device, its _EJ0 should be executed by the dock
269 	 * notify handler after calling _DCK.
270 	 */
271 	if (!is_dock_device(adev) && acpi_has_method(handle, "_EJ0"))
272 		newfunc->flags = FUNC_HAS_EJ0;
273 
274 	if (acpi_has_method(handle, "_STA"))
275 		newfunc->flags |= FUNC_HAS_STA;
276 
277 	/* search for objects that share the same slot */
278 	list_for_each_entry(slot, &bridge->slots, node)
279 		if (slot->device == device)
280 			goto slot_found;
281 
282 	slot = kzalloc(sizeof(struct acpiphp_slot), GFP_KERNEL);
283 	if (!slot) {
284 		acpi_lock_hp_context();
285 		acpiphp_put_context(context);
286 		acpi_unlock_hp_context();
287 		return AE_NO_MEMORY;
288 	}
289 
290 	slot->bus = bridge->pci_bus;
291 	slot->device = device;
292 	INIT_LIST_HEAD(&slot->funcs);
293 
294 	list_add_tail(&slot->node, &bridge->slots);
295 
296 	/*
297 	 * Expose slots to user space for functions that have _EJ0 or _RMV or
298 	 * are located in dock stations.  Do not expose them for devices handled
299 	 * by the native PCIe hotplug (PCIeHP) or standard PCI hotplug
300 	 * (SHPCHP), because that code is supposed to expose slots to user
301 	 * space in those cases.
302 	 */
303 	if ((acpi_pci_check_ejectable(pbus, handle) || is_dock_device(adev))
304 	    && !(pdev && hotplug_is_native(pdev))) {
305 		unsigned long long sun;
306 		int retval;
307 
308 		bridge->nr_slots++;
309 		status = acpi_evaluate_integer(handle, "_SUN", NULL, &sun);
310 		if (ACPI_FAILURE(status))
311 			sun = bridge->nr_slots;
312 
313 		pr_debug("found ACPI PCI Hotplug slot %llu at PCI %04x:%02x:%02x\n",
314 		    sun, pci_domain_nr(pbus), pbus->number, device);
315 
316 		retval = acpiphp_register_hotplug_slot(slot, sun);
317 		if (retval) {
318 			slot->slot = NULL;
319 			bridge->nr_slots--;
320 			if (retval == -EBUSY)
321 				pr_warn("Slot %llu already registered by another hotplug driver\n", sun);
322 			else
323 				pr_warn("acpiphp_register_hotplug_slot failed (err code = 0x%x)\n", retval);
324 		}
325 		/* Even if the slot registration fails, we can still use it. */
326 	}
327 
328  slot_found:
329 	newfunc->slot = slot;
330 	list_add_tail(&newfunc->sibling, &slot->funcs);
331 
332 	if (pci_bus_read_dev_vendor_id(pbus, PCI_DEVFN(device, function),
333 				       &val, 60*1000))
334 		slot->flags |= SLOT_ENABLED;
335 
336 	return AE_OK;
337 }
338 
339 static void cleanup_bridge(struct acpiphp_bridge *bridge)
340 {
341 	struct acpiphp_slot *slot;
342 	struct acpiphp_func *func;
343 
344 	list_for_each_entry(slot, &bridge->slots, node) {
345 		list_for_each_entry(func, &slot->funcs, sibling) {
346 			struct acpi_device *adev = func_to_acpi_device(func);
347 
348 			acpi_lock_hp_context();
349 			adev->hp->notify = NULL;
350 			adev->hp->fixup = NULL;
351 			acpi_unlock_hp_context();
352 		}
353 		slot->flags |= SLOT_IS_GOING_AWAY;
354 		if (slot->slot)
355 			acpiphp_unregister_hotplug_slot(slot);
356 	}
357 
358 	mutex_lock(&bridge_mutex);
359 	list_del(&bridge->list);
360 	mutex_unlock(&bridge_mutex);
361 
362 	acpi_lock_hp_context();
363 	bridge->is_going_away = true;
364 	acpi_unlock_hp_context();
365 }
366 
367 /**
368  * acpiphp_max_busnr - return the highest reserved bus number under the given bus.
369  * @bus: bus to start search with
370  */
371 static unsigned char acpiphp_max_busnr(struct pci_bus *bus)
372 {
373 	struct pci_bus *tmp;
374 	unsigned char max, n;
375 
376 	/*
377 	 * pci_bus_max_busnr will return the highest
378 	 * reserved busnr for all these children.
379 	 * that is equivalent to the bus->subordinate
380 	 * value.  We don't want to use the parent's
381 	 * bus->subordinate value because it could have
382 	 * padding in it.
383 	 */
384 	max = bus->busn_res.start;
385 
386 	list_for_each_entry(tmp, &bus->children, node) {
387 		n = pci_bus_max_busnr(tmp);
388 		if (n > max)
389 			max = n;
390 	}
391 	return max;
392 }
393 
394 static void acpiphp_set_acpi_region(struct acpiphp_slot *slot)
395 {
396 	struct acpiphp_func *func;
397 
398 	list_for_each_entry(func, &slot->funcs, sibling) {
399 		/* _REG is optional, we don't care about if there is failure */
400 		acpi_evaluate_reg(func_to_handle(func),
401 				  ACPI_ADR_SPACE_PCI_CONFIG,
402 				  ACPI_REG_CONNECT);
403 	}
404 }
405 
406 static void check_hotplug_bridge(struct acpiphp_slot *slot, struct pci_dev *dev)
407 {
408 	struct acpiphp_func *func;
409 
410 	/* quirk, or pcie could set it already */
411 	if (dev->is_hotplug_bridge)
412 		return;
413 
414 	/*
415 	 * In the PCIe case, only Root Ports and Downstream Ports are capable of
416 	 * accommodating hotplug devices, so avoid marking Upstream Ports as
417 	 * "hotplug bridges".
418 	 */
419 	if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_UPSTREAM)
420 		return;
421 
422 	list_for_each_entry(func, &slot->funcs, sibling) {
423 		if (PCI_FUNC(dev->devfn) == func->function) {
424 			dev->is_hotplug_bridge = 1;
425 			break;
426 		}
427 	}
428 }
429 
430 static int acpiphp_rescan_slot(struct acpiphp_slot *slot)
431 {
432 	struct acpiphp_func *func;
433 
434 	list_for_each_entry(func, &slot->funcs, sibling) {
435 		struct acpi_device *adev = func_to_acpi_device(func);
436 
437 		acpi_bus_scan(adev->handle);
438 		if (acpi_device_enumerated(adev))
439 			acpi_device_set_power(adev, ACPI_STATE_D0);
440 	}
441 	return pci_scan_slot(slot->bus, PCI_DEVFN(slot->device, 0));
442 }
443 
444 static void acpiphp_native_scan_bridge(struct pci_dev *bridge)
445 {
446 	struct pci_bus *bus = bridge->subordinate;
447 	struct pci_dev *dev;
448 	int max;
449 
450 	if (!bus)
451 		return;
452 
453 	max = bus->busn_res.start;
454 	/* Scan already configured non-hotplug bridges */
455 	for_each_pci_bridge(dev, bus) {
456 		if (!hotplug_is_native(dev))
457 			max = pci_scan_bridge(bus, dev, max, 0);
458 	}
459 
460 	/* Scan non-hotplug bridges that need to be reconfigured */
461 	for_each_pci_bridge(dev, bus) {
462 		if (hotplug_is_native(dev))
463 			continue;
464 
465 		max = pci_scan_bridge(bus, dev, max, 1);
466 		if (dev->subordinate) {
467 			pcibios_resource_survey_bus(dev->subordinate);
468 			pci_bus_size_bridges(dev->subordinate);
469 			pci_bus_assign_resources(dev->subordinate);
470 		}
471 	}
472 }
473 
474 /**
475  * enable_slot - enable, configure a slot
476  * @slot: slot to be enabled
477  * @bridge: true if enable is for the whole bridge (not a single slot)
478  *
479  * This function should be called per *physical slot*,
480  * not per each slot object in ACPI namespace.
481  */
482 static void enable_slot(struct acpiphp_slot *slot, bool bridge)
483 {
484 	struct pci_dev *dev;
485 	struct pci_bus *bus = slot->bus;
486 	struct acpiphp_func *func;
487 
488 	if (bridge && bus->self && hotplug_is_native(bus->self)) {
489 		/*
490 		 * If native hotplug is used, it will take care of hotplug
491 		 * slot management and resource allocation for hotplug
492 		 * bridges. However, ACPI hotplug may still be used for
493 		 * non-hotplug bridges to bring in additional devices such
494 		 * as a Thunderbolt host controller.
495 		 */
496 		for_each_pci_bridge(dev, bus) {
497 			if (PCI_SLOT(dev->devfn) == slot->device)
498 				acpiphp_native_scan_bridge(dev);
499 		}
500 	} else {
501 		LIST_HEAD(add_list);
502 		int max, pass;
503 
504 		acpiphp_rescan_slot(slot);
505 		max = acpiphp_max_busnr(bus);
506 		for (pass = 0; pass < 2; pass++) {
507 			for_each_pci_bridge(dev, bus) {
508 				if (PCI_SLOT(dev->devfn) != slot->device)
509 					continue;
510 
511 				max = pci_scan_bridge(bus, dev, max, pass);
512 				if (pass && dev->subordinate) {
513 					check_hotplug_bridge(slot, dev);
514 					pcibios_resource_survey_bus(dev->subordinate);
515 					if (pci_is_root_bus(bus))
516 						__pci_bus_size_bridges(dev->subordinate, &add_list);
517 				}
518 			}
519 		}
520 		if (pci_is_root_bus(bus))
521 			__pci_bus_assign_resources(bus, &add_list, NULL);
522 		else
523 			pci_assign_unassigned_bridge_resources(bus->self);
524 	}
525 
526 	acpiphp_sanitize_bus(bus);
527 	pcie_bus_configure_settings(bus);
528 	acpiphp_set_acpi_region(slot);
529 
530 	list_for_each_entry(dev, &bus->devices, bus_list) {
531 		/* Assume that newly added devices are powered on already. */
532 		if (!pci_dev_is_added(dev))
533 			dev->current_state = PCI_D0;
534 	}
535 
536 	pci_bus_add_devices(bus);
537 
538 	slot->flags |= SLOT_ENABLED;
539 	list_for_each_entry(func, &slot->funcs, sibling) {
540 		dev = pci_get_slot(bus, PCI_DEVFN(slot->device,
541 						  func->function));
542 		if (!dev) {
543 			/* Do not set SLOT_ENABLED flag if some funcs
544 			   are not added. */
545 			slot->flags &= ~SLOT_ENABLED;
546 			continue;
547 		}
548 		pci_dev_put(dev);
549 	}
550 }
551 
552 /**
553  * disable_slot - disable a slot
554  * @slot: ACPI PHP slot
555  */
556 static void disable_slot(struct acpiphp_slot *slot)
557 {
558 	struct pci_bus *bus = slot->bus;
559 	struct pci_dev *dev, *prev;
560 	struct acpiphp_func *func;
561 
562 	/*
563 	 * enable_slot() enumerates all functions in this device via
564 	 * pci_scan_slot(), whether they have associated ACPI hotplug
565 	 * methods (_EJ0, etc.) or not.  Therefore, we remove all functions
566 	 * here.
567 	 */
568 	list_for_each_entry_safe_reverse(dev, prev, &bus->devices, bus_list)
569 		if (PCI_SLOT(dev->devfn) == slot->device)
570 			pci_stop_and_remove_bus_device(dev);
571 
572 	list_for_each_entry(func, &slot->funcs, sibling)
573 		acpi_bus_trim(func_to_acpi_device(func));
574 
575 	slot->flags &= ~SLOT_ENABLED;
576 }
577 
578 static bool slot_no_hotplug(struct acpiphp_slot *slot)
579 {
580 	struct pci_bus *bus = slot->bus;
581 	struct pci_dev *dev;
582 
583 	list_for_each_entry(dev, &bus->devices, bus_list) {
584 		if (PCI_SLOT(dev->devfn) == slot->device && dev->ignore_hotplug)
585 			return true;
586 	}
587 	return false;
588 }
589 
590 /**
591  * get_slot_status - get ACPI slot status
592  * @slot: ACPI PHP slot
593  *
594  * If a slot has _STA for each function and if any one of them
595  * returned non-zero status, return it.
596  *
597  * If a slot doesn't have _STA and if any one of its functions'
598  * configuration space is configured, return 0x0f as a _STA.
599  *
600  * Otherwise return 0.
601  */
602 static unsigned int get_slot_status(struct acpiphp_slot *slot)
603 {
604 	unsigned long long sta = 0;
605 	struct acpiphp_func *func;
606 	u32 dvid;
607 
608 	list_for_each_entry(func, &slot->funcs, sibling) {
609 		if (func->flags & FUNC_HAS_STA) {
610 			acpi_status status;
611 
612 			status = acpi_evaluate_integer(func_to_handle(func),
613 						       "_STA", NULL, &sta);
614 			if (ACPI_SUCCESS(status) && sta)
615 				break;
616 		} else {
617 			if (pci_bus_read_dev_vendor_id(slot->bus,
618 					PCI_DEVFN(slot->device, func->function),
619 					&dvid, 0)) {
620 				sta = ACPI_STA_ALL;
621 				break;
622 			}
623 		}
624 	}
625 
626 	if (!sta) {
627 		/*
628 		 * Check for the slot itself since it may be that the
629 		 * ACPI slot is a device below PCIe upstream port so in
630 		 * that case it may not even be reachable yet.
631 		 */
632 		if (pci_bus_read_dev_vendor_id(slot->bus,
633 				PCI_DEVFN(slot->device, 0), &dvid, 0)) {
634 			sta = ACPI_STA_ALL;
635 		}
636 	}
637 
638 	return (unsigned int)sta;
639 }
640 
641 static inline bool device_status_valid(unsigned int sta)
642 {
643 	/*
644 	 * ACPI spec says that _STA may return bit 0 clear with bit 3 set
645 	 * if the device is valid but does not require a device driver to be
646 	 * loaded (Section 6.3.7 of ACPI 5.0A).
647 	 */
648 	unsigned int mask = ACPI_STA_DEVICE_ENABLED | ACPI_STA_DEVICE_FUNCTIONING;
649 	return (sta & mask) == mask;
650 }
651 
652 /**
653  * trim_stale_devices - remove PCI devices that are not responding.
654  * @dev: PCI device to start walking the hierarchy from.
655  */
656 static void trim_stale_devices(struct pci_dev *dev)
657 {
658 	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
659 	struct pci_bus *bus = dev->subordinate;
660 	bool alive = dev->ignore_hotplug;
661 
662 	if (adev) {
663 		acpi_status status;
664 		unsigned long long sta;
665 
666 		status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
667 		alive = alive || (ACPI_SUCCESS(status) && device_status_valid(sta));
668 	}
669 	if (!alive)
670 		alive = pci_device_is_present(dev);
671 
672 	if (!alive) {
673 		pci_dev_set_disconnected(dev, NULL);
674 		if (pci_has_subordinate(dev))
675 			pci_walk_bus(dev->subordinate, pci_dev_set_disconnected,
676 				     NULL);
677 
678 		pci_stop_and_remove_bus_device(dev);
679 		if (adev)
680 			acpi_bus_trim(adev);
681 	} else if (bus) {
682 		struct pci_dev *child, *tmp;
683 
684 		/* The device is a bridge. so check the bus below it. */
685 		pm_runtime_get_sync(&dev->dev);
686 		list_for_each_entry_safe_reverse(child, tmp, &bus->devices, bus_list)
687 			trim_stale_devices(child);
688 
689 		pm_runtime_put(&dev->dev);
690 	}
691 }
692 
693 /**
694  * acpiphp_check_bridge - re-enumerate devices
695  * @bridge: where to begin re-enumeration
696  *
697  * Iterate over all slots under this bridge and make sure that if a
698  * card is present they are enabled, and if not they are disabled.
699  */
700 static void acpiphp_check_bridge(struct acpiphp_bridge *bridge)
701 {
702 	struct acpiphp_slot *slot;
703 
704 	/* Bail out if the bridge is going away. */
705 	if (bridge->is_going_away)
706 		return;
707 
708 	if (bridge->pci_dev)
709 		pm_runtime_get_sync(&bridge->pci_dev->dev);
710 
711 	list_for_each_entry(slot, &bridge->slots, node) {
712 		struct pci_bus *bus = slot->bus;
713 		struct pci_dev *dev, *tmp;
714 
715 		if (slot_no_hotplug(slot)) {
716 			; /* do nothing */
717 		} else if (device_status_valid(get_slot_status(slot))) {
718 			/* remove stale devices if any */
719 			list_for_each_entry_safe_reverse(dev, tmp,
720 							 &bus->devices, bus_list)
721 				if (PCI_SLOT(dev->devfn) == slot->device)
722 					trim_stale_devices(dev);
723 
724 			/* configure all functions */
725 			enable_slot(slot, true);
726 		} else {
727 			disable_slot(slot);
728 		}
729 	}
730 
731 	if (bridge->pci_dev)
732 		pm_runtime_put(&bridge->pci_dev->dev);
733 }
734 
735 /*
736  * Remove devices for which we could not assign resources, call
737  * arch specific code to fix-up the bus
738  */
739 static void acpiphp_sanitize_bus(struct pci_bus *bus)
740 {
741 	struct pci_dev *dev, *tmp;
742 	int i;
743 	unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM;
744 
745 	list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) {
746 		for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) {
747 			struct resource *res = &dev->resource[i];
748 			if ((res->flags & type_mask) && !res->start &&
749 					res->end) {
750 				/* Could not assign a required resources
751 				 * for this device, remove it */
752 				pci_stop_and_remove_bus_device(dev);
753 				break;
754 			}
755 		}
756 	}
757 }
758 
759 /*
760  * ACPI event handlers
761  */
762 
763 void acpiphp_check_host_bridge(struct acpi_device *adev)
764 {
765 	struct acpiphp_bridge *bridge = NULL;
766 
767 	acpi_lock_hp_context();
768 	if (adev->hp) {
769 		bridge = to_acpiphp_root_context(adev->hp)->root_bridge;
770 		if (bridge)
771 			get_bridge(bridge);
772 	}
773 	acpi_unlock_hp_context();
774 	if (bridge) {
775 		pci_lock_rescan_remove();
776 
777 		acpiphp_check_bridge(bridge);
778 
779 		pci_unlock_rescan_remove();
780 		put_bridge(bridge);
781 	}
782 }
783 
784 static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot);
785 
786 static void hotplug_event(u32 type, struct acpiphp_context *context)
787 {
788 	acpi_handle handle = context->hp.self->handle;
789 	struct acpiphp_func *func = &context->func;
790 	struct acpiphp_slot *slot = func->slot;
791 	struct acpiphp_bridge *bridge;
792 
793 	acpi_lock_hp_context();
794 	bridge = context->bridge;
795 	if (bridge)
796 		get_bridge(bridge);
797 
798 	acpi_unlock_hp_context();
799 
800 	pci_lock_rescan_remove();
801 
802 	switch (type) {
803 	case ACPI_NOTIFY_BUS_CHECK:
804 		/* bus re-enumerate */
805 		acpi_handle_debug(handle, "Bus check in %s()\n", __func__);
806 		if (bridge)
807 			acpiphp_check_bridge(bridge);
808 		else if (!(slot->flags & SLOT_IS_GOING_AWAY))
809 			enable_slot(slot, false);
810 
811 		break;
812 
813 	case ACPI_NOTIFY_DEVICE_CHECK:
814 		/* device check */
815 		acpi_handle_debug(handle, "Device check in %s()\n", __func__);
816 		if (bridge) {
817 			acpiphp_check_bridge(bridge);
818 		} else if (!(slot->flags & SLOT_IS_GOING_AWAY)) {
819 			/*
820 			 * Check if anything has changed in the slot and rescan
821 			 * from the parent if that's the case.
822 			 */
823 			if (acpiphp_rescan_slot(slot))
824 				acpiphp_check_bridge(func->parent);
825 		}
826 		break;
827 
828 	case ACPI_NOTIFY_EJECT_REQUEST:
829 		/* request device eject */
830 		acpi_handle_debug(handle, "Eject request in %s()\n", __func__);
831 		acpiphp_disable_and_eject_slot(slot);
832 		break;
833 	}
834 
835 	pci_unlock_rescan_remove();
836 	if (bridge)
837 		put_bridge(bridge);
838 }
839 
840 static int acpiphp_hotplug_notify(struct acpi_device *adev, u32 type)
841 {
842 	struct acpiphp_context *context;
843 
844 	context = acpiphp_grab_context(adev);
845 	if (!context)
846 		return -ENODATA;
847 
848 	hotplug_event(type, context);
849 	acpiphp_let_context_go(context);
850 	return 0;
851 }
852 
853 /**
854  * acpiphp_enumerate_slots - Enumerate PCI slots for a given bus.
855  * @bus: PCI bus to enumerate the slots for.
856  *
857  * A "slot" is an object associated with a PCI device number.  All functions
858  * (PCI devices) with the same bus and device number belong to the same slot.
859  */
860 void acpiphp_enumerate_slots(struct pci_bus *bus)
861 {
862 	struct acpiphp_bridge *bridge;
863 	struct acpi_device *adev;
864 	acpi_handle handle;
865 	acpi_status status;
866 
867 	if (acpiphp_disabled)
868 		return;
869 
870 	adev = ACPI_COMPANION(bus->bridge);
871 	if (!adev)
872 		return;
873 
874 	handle = adev->handle;
875 	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
876 	if (!bridge)
877 		return;
878 
879 	INIT_LIST_HEAD(&bridge->slots);
880 	kref_init(&bridge->ref);
881 	bridge->pci_dev = pci_dev_get(bus->self);
882 	bridge->pci_bus = bus;
883 
884 	/*
885 	 * Grab a ref to the subordinate PCI bus in case the bus is
886 	 * removed via PCI core logical hotplug. The ref pins the bus
887 	 * (which we access during module unload).
888 	 */
889 	get_device(&bus->dev);
890 
891 	acpi_lock_hp_context();
892 	if (pci_is_root_bus(bridge->pci_bus)) {
893 		struct acpiphp_root_context *root_context;
894 
895 		root_context = kzalloc(sizeof(*root_context), GFP_KERNEL);
896 		if (!root_context)
897 			goto err;
898 
899 		root_context->root_bridge = bridge;
900 		acpi_set_hp_context(adev, &root_context->hp);
901 	} else {
902 		struct acpiphp_context *context;
903 
904 		/*
905 		 * This bridge should have been registered as a hotplug function
906 		 * under its parent, so the context should be there, unless the
907 		 * parent is going to be handled by pciehp, in which case this
908 		 * bridge is not interesting to us either.
909 		 */
910 		context = acpiphp_get_context(adev);
911 		if (!context)
912 			goto err;
913 
914 		bridge->context = context;
915 		context->bridge = bridge;
916 		/* Get a reference to the parent bridge. */
917 		get_bridge(context->func.parent);
918 	}
919 	acpi_unlock_hp_context();
920 
921 	/* Must be added to the list prior to calling acpiphp_add_context(). */
922 	mutex_lock(&bridge_mutex);
923 	list_add(&bridge->list, &bridge_list);
924 	mutex_unlock(&bridge_mutex);
925 
926 	/* register all slot objects under this bridge */
927 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
928 				     acpiphp_add_context, NULL, bridge, NULL);
929 	if (ACPI_FAILURE(status)) {
930 		acpi_handle_err(handle, "failed to register slots\n");
931 		cleanup_bridge(bridge);
932 		put_bridge(bridge);
933 	}
934 	return;
935 
936  err:
937 	acpi_unlock_hp_context();
938 	put_device(&bus->dev);
939 	pci_dev_put(bridge->pci_dev);
940 	kfree(bridge);
941 }
942 
943 static void acpiphp_drop_bridge(struct acpiphp_bridge *bridge)
944 {
945 	if (pci_is_root_bus(bridge->pci_bus)) {
946 		struct acpiphp_root_context *root_context;
947 		struct acpi_device *adev;
948 
949 		acpi_lock_hp_context();
950 		adev = ACPI_COMPANION(bridge->pci_bus->bridge);
951 		root_context = to_acpiphp_root_context(adev->hp);
952 		adev->hp = NULL;
953 		acpi_unlock_hp_context();
954 		kfree(root_context);
955 	}
956 	cleanup_bridge(bridge);
957 	put_bridge(bridge);
958 }
959 
960 /**
961  * acpiphp_remove_slots - Remove slot objects associated with a given bus.
962  * @bus: PCI bus to remove the slot objects for.
963  */
964 void acpiphp_remove_slots(struct pci_bus *bus)
965 {
966 	struct acpiphp_bridge *bridge;
967 
968 	if (acpiphp_disabled)
969 		return;
970 
971 	mutex_lock(&bridge_mutex);
972 	list_for_each_entry(bridge, &bridge_list, list)
973 		if (bridge->pci_bus == bus) {
974 			mutex_unlock(&bridge_mutex);
975 			acpiphp_drop_bridge(bridge);
976 			return;
977 		}
978 
979 	mutex_unlock(&bridge_mutex);
980 }
981 
982 /**
983  * acpiphp_enable_slot - power on slot
984  * @slot: ACPI PHP slot
985  */
986 int acpiphp_enable_slot(struct acpiphp_slot *slot)
987 {
988 	pci_lock_rescan_remove();
989 
990 	if (slot->flags & SLOT_IS_GOING_AWAY) {
991 		pci_unlock_rescan_remove();
992 		return -ENODEV;
993 	}
994 
995 	/* configure all functions */
996 	if (!(slot->flags & SLOT_ENABLED))
997 		enable_slot(slot, false);
998 
999 	pci_unlock_rescan_remove();
1000 	return 0;
1001 }
1002 
1003 /**
1004  * acpiphp_disable_and_eject_slot - power off and eject slot
1005  * @slot: ACPI PHP slot
1006  */
1007 static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot)
1008 {
1009 	struct acpiphp_func *func;
1010 
1011 	if (slot->flags & SLOT_IS_GOING_AWAY)
1012 		return -ENODEV;
1013 
1014 	/* unconfigure all functions */
1015 	disable_slot(slot);
1016 
1017 	list_for_each_entry(func, &slot->funcs, sibling)
1018 		if (func->flags & FUNC_HAS_EJ0) {
1019 			acpi_handle handle = func_to_handle(func);
1020 
1021 			if (ACPI_FAILURE(acpi_evaluate_ej0(handle)))
1022 				acpi_handle_err(handle, "_EJ0 failed\n");
1023 
1024 			break;
1025 		}
1026 
1027 	return 0;
1028 }
1029 
1030 int acpiphp_disable_slot(struct acpiphp_slot *slot)
1031 {
1032 	int ret;
1033 
1034 	/*
1035 	 * Acquire acpi_scan_lock to ensure that the execution of _EJ0 in
1036 	 * acpiphp_disable_and_eject_slot() will be synchronized properly.
1037 	 */
1038 	acpi_scan_lock_acquire();
1039 	pci_lock_rescan_remove();
1040 	ret = acpiphp_disable_and_eject_slot(slot);
1041 	pci_unlock_rescan_remove();
1042 	acpi_scan_lock_release();
1043 	return ret;
1044 }
1045 
1046 /*
1047  * slot enabled:  1
1048  * slot disabled: 0
1049  */
1050 u8 acpiphp_get_power_status(struct acpiphp_slot *slot)
1051 {
1052 	return (slot->flags & SLOT_ENABLED);
1053 }
1054 
1055 /*
1056  * latch   open:  1
1057  * latch closed:  0
1058  */
1059 u8 acpiphp_get_latch_status(struct acpiphp_slot *slot)
1060 {
1061 	return !(get_slot_status(slot) & ACPI_STA_DEVICE_UI);
1062 }
1063 
1064 /*
1065  * adapter presence : 1
1066  *          absence : 0
1067  */
1068 u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot)
1069 {
1070 	return !!get_slot_status(slot);
1071 }
1072