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 	list_for_each_entry(func, &slot->funcs, sibling) {
415 		if (PCI_FUNC(dev->devfn) == func->function) {
416 			dev->is_hotplug_bridge = 1;
417 			break;
418 		}
419 	}
420 }
421 
422 static int acpiphp_rescan_slot(struct acpiphp_slot *slot)
423 {
424 	struct acpiphp_func *func;
425 
426 	list_for_each_entry(func, &slot->funcs, sibling) {
427 		struct acpi_device *adev = func_to_acpi_device(func);
428 
429 		acpi_bus_scan(adev->handle);
430 		if (acpi_device_enumerated(adev))
431 			acpi_device_set_power(adev, ACPI_STATE_D0);
432 	}
433 	return pci_scan_slot(slot->bus, PCI_DEVFN(slot->device, 0));
434 }
435 
436 static void acpiphp_native_scan_bridge(struct pci_dev *bridge)
437 {
438 	struct pci_bus *bus = bridge->subordinate;
439 	struct pci_dev *dev;
440 	int max;
441 
442 	if (!bus)
443 		return;
444 
445 	max = bus->busn_res.start;
446 	/* Scan already configured non-hotplug bridges */
447 	for_each_pci_bridge(dev, bus) {
448 		if (!hotplug_is_native(dev))
449 			max = pci_scan_bridge(bus, dev, max, 0);
450 	}
451 
452 	/* Scan non-hotplug bridges that need to be reconfigured */
453 	for_each_pci_bridge(dev, bus) {
454 		if (hotplug_is_native(dev))
455 			continue;
456 
457 		max = pci_scan_bridge(bus, dev, max, 1);
458 		if (dev->subordinate) {
459 			pcibios_resource_survey_bus(dev->subordinate);
460 			pci_bus_size_bridges(dev->subordinate);
461 			pci_bus_assign_resources(dev->subordinate);
462 		}
463 	}
464 }
465 
466 /**
467  * enable_slot - enable, configure a slot
468  * @slot: slot to be enabled
469  * @bridge: true if enable is for the whole bridge (not a single slot)
470  *
471  * This function should be called per *physical slot*,
472  * not per each slot object in ACPI namespace.
473  */
474 static void enable_slot(struct acpiphp_slot *slot, bool bridge)
475 {
476 	struct pci_dev *dev;
477 	struct pci_bus *bus = slot->bus;
478 	struct acpiphp_func *func;
479 
480 	if (bridge && bus->self && hotplug_is_native(bus->self)) {
481 		/*
482 		 * If native hotplug is used, it will take care of hotplug
483 		 * slot management and resource allocation for hotplug
484 		 * bridges. However, ACPI hotplug may still be used for
485 		 * non-hotplug bridges to bring in additional devices such
486 		 * as a Thunderbolt host controller.
487 		 */
488 		for_each_pci_bridge(dev, bus) {
489 			if (PCI_SLOT(dev->devfn) == slot->device)
490 				acpiphp_native_scan_bridge(dev);
491 		}
492 	} else {
493 		LIST_HEAD(add_list);
494 		int max, pass;
495 
496 		acpiphp_rescan_slot(slot);
497 		max = acpiphp_max_busnr(bus);
498 		for (pass = 0; pass < 2; pass++) {
499 			for_each_pci_bridge(dev, bus) {
500 				if (PCI_SLOT(dev->devfn) != slot->device)
501 					continue;
502 
503 				max = pci_scan_bridge(bus, dev, max, pass);
504 				if (pass && dev->subordinate) {
505 					check_hotplug_bridge(slot, dev);
506 					pcibios_resource_survey_bus(dev->subordinate);
507 					__pci_bus_size_bridges(dev->subordinate,
508 							       &add_list);
509 				}
510 			}
511 		}
512 		__pci_bus_assign_resources(bus, &add_list, NULL);
513 	}
514 
515 	acpiphp_sanitize_bus(bus);
516 	pcie_bus_configure_settings(bus);
517 	acpiphp_set_acpi_region(slot);
518 
519 	list_for_each_entry(dev, &bus->devices, bus_list) {
520 		/* Assume that newly added devices are powered on already. */
521 		if (!pci_dev_is_added(dev))
522 			dev->current_state = PCI_D0;
523 	}
524 
525 	pci_bus_add_devices(bus);
526 
527 	slot->flags |= SLOT_ENABLED;
528 	list_for_each_entry(func, &slot->funcs, sibling) {
529 		dev = pci_get_slot(bus, PCI_DEVFN(slot->device,
530 						  func->function));
531 		if (!dev) {
532 			/* Do not set SLOT_ENABLED flag if some funcs
533 			   are not added. */
534 			slot->flags &= ~SLOT_ENABLED;
535 			continue;
536 		}
537 		pci_dev_put(dev);
538 	}
539 }
540 
541 /**
542  * disable_slot - disable a slot
543  * @slot: ACPI PHP slot
544  */
545 static void disable_slot(struct acpiphp_slot *slot)
546 {
547 	struct pci_bus *bus = slot->bus;
548 	struct pci_dev *dev, *prev;
549 	struct acpiphp_func *func;
550 
551 	/*
552 	 * enable_slot() enumerates all functions in this device via
553 	 * pci_scan_slot(), whether they have associated ACPI hotplug
554 	 * methods (_EJ0, etc.) or not.  Therefore, we remove all functions
555 	 * here.
556 	 */
557 	list_for_each_entry_safe_reverse(dev, prev, &bus->devices, bus_list)
558 		if (PCI_SLOT(dev->devfn) == slot->device)
559 			pci_stop_and_remove_bus_device(dev);
560 
561 	list_for_each_entry(func, &slot->funcs, sibling)
562 		acpi_bus_trim(func_to_acpi_device(func));
563 
564 	slot->flags &= ~SLOT_ENABLED;
565 }
566 
567 static bool slot_no_hotplug(struct acpiphp_slot *slot)
568 {
569 	struct pci_bus *bus = slot->bus;
570 	struct pci_dev *dev;
571 
572 	list_for_each_entry(dev, &bus->devices, bus_list) {
573 		if (PCI_SLOT(dev->devfn) == slot->device && dev->ignore_hotplug)
574 			return true;
575 	}
576 	return false;
577 }
578 
579 /**
580  * get_slot_status - get ACPI slot status
581  * @slot: ACPI PHP slot
582  *
583  * If a slot has _STA for each function and if any one of them
584  * returned non-zero status, return it.
585  *
586  * If a slot doesn't have _STA and if any one of its functions'
587  * configuration space is configured, return 0x0f as a _STA.
588  *
589  * Otherwise return 0.
590  */
591 static unsigned int get_slot_status(struct acpiphp_slot *slot)
592 {
593 	unsigned long long sta = 0;
594 	struct acpiphp_func *func;
595 	u32 dvid;
596 
597 	list_for_each_entry(func, &slot->funcs, sibling) {
598 		if (func->flags & FUNC_HAS_STA) {
599 			acpi_status status;
600 
601 			status = acpi_evaluate_integer(func_to_handle(func),
602 						       "_STA", NULL, &sta);
603 			if (ACPI_SUCCESS(status) && sta)
604 				break;
605 		} else {
606 			if (pci_bus_read_dev_vendor_id(slot->bus,
607 					PCI_DEVFN(slot->device, func->function),
608 					&dvid, 0)) {
609 				sta = ACPI_STA_ALL;
610 				break;
611 			}
612 		}
613 	}
614 
615 	if (!sta) {
616 		/*
617 		 * Check for the slot itself since it may be that the
618 		 * ACPI slot is a device below PCIe upstream port so in
619 		 * that case it may not even be reachable yet.
620 		 */
621 		if (pci_bus_read_dev_vendor_id(slot->bus,
622 				PCI_DEVFN(slot->device, 0), &dvid, 0)) {
623 			sta = ACPI_STA_ALL;
624 		}
625 	}
626 
627 	return (unsigned int)sta;
628 }
629 
630 static inline bool device_status_valid(unsigned int sta)
631 {
632 	/*
633 	 * ACPI spec says that _STA may return bit 0 clear with bit 3 set
634 	 * if the device is valid but does not require a device driver to be
635 	 * loaded (Section 6.3.7 of ACPI 5.0A).
636 	 */
637 	unsigned int mask = ACPI_STA_DEVICE_ENABLED | ACPI_STA_DEVICE_FUNCTIONING;
638 	return (sta & mask) == mask;
639 }
640 
641 /**
642  * trim_stale_devices - remove PCI devices that are not responding.
643  * @dev: PCI device to start walking the hierarchy from.
644  */
645 static void trim_stale_devices(struct pci_dev *dev)
646 {
647 	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
648 	struct pci_bus *bus = dev->subordinate;
649 	bool alive = dev->ignore_hotplug;
650 
651 	if (adev) {
652 		acpi_status status;
653 		unsigned long long sta;
654 
655 		status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
656 		alive = alive || (ACPI_SUCCESS(status) && device_status_valid(sta));
657 	}
658 	if (!alive)
659 		alive = pci_device_is_present(dev);
660 
661 	if (!alive) {
662 		pci_dev_set_disconnected(dev, NULL);
663 		if (pci_has_subordinate(dev))
664 			pci_walk_bus(dev->subordinate, pci_dev_set_disconnected,
665 				     NULL);
666 
667 		pci_stop_and_remove_bus_device(dev);
668 		if (adev)
669 			acpi_bus_trim(adev);
670 	} else if (bus) {
671 		struct pci_dev *child, *tmp;
672 
673 		/* The device is a bridge. so check the bus below it. */
674 		pm_runtime_get_sync(&dev->dev);
675 		list_for_each_entry_safe_reverse(child, tmp, &bus->devices, bus_list)
676 			trim_stale_devices(child);
677 
678 		pm_runtime_put(&dev->dev);
679 	}
680 }
681 
682 /**
683  * acpiphp_check_bridge - re-enumerate devices
684  * @bridge: where to begin re-enumeration
685  *
686  * Iterate over all slots under this bridge and make sure that if a
687  * card is present they are enabled, and if not they are disabled.
688  */
689 static void acpiphp_check_bridge(struct acpiphp_bridge *bridge)
690 {
691 	struct acpiphp_slot *slot;
692 
693 	/* Bail out if the bridge is going away. */
694 	if (bridge->is_going_away)
695 		return;
696 
697 	if (bridge->pci_dev)
698 		pm_runtime_get_sync(&bridge->pci_dev->dev);
699 
700 	list_for_each_entry(slot, &bridge->slots, node) {
701 		struct pci_bus *bus = slot->bus;
702 		struct pci_dev *dev, *tmp;
703 
704 		if (slot_no_hotplug(slot)) {
705 			; /* do nothing */
706 		} else if (device_status_valid(get_slot_status(slot))) {
707 			/* remove stale devices if any */
708 			list_for_each_entry_safe_reverse(dev, tmp,
709 							 &bus->devices, bus_list)
710 				if (PCI_SLOT(dev->devfn) == slot->device)
711 					trim_stale_devices(dev);
712 
713 			/* configure all functions */
714 			enable_slot(slot, true);
715 		} else {
716 			disable_slot(slot);
717 		}
718 	}
719 
720 	if (bridge->pci_dev)
721 		pm_runtime_put(&bridge->pci_dev->dev);
722 }
723 
724 /*
725  * Remove devices for which we could not assign resources, call
726  * arch specific code to fix-up the bus
727  */
728 static void acpiphp_sanitize_bus(struct pci_bus *bus)
729 {
730 	struct pci_dev *dev, *tmp;
731 	int i;
732 	unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM;
733 
734 	list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) {
735 		for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) {
736 			struct resource *res = &dev->resource[i];
737 			if ((res->flags & type_mask) && !res->start &&
738 					res->end) {
739 				/* Could not assign a required resources
740 				 * for this device, remove it */
741 				pci_stop_and_remove_bus_device(dev);
742 				break;
743 			}
744 		}
745 	}
746 }
747 
748 /*
749  * ACPI event handlers
750  */
751 
752 void acpiphp_check_host_bridge(struct acpi_device *adev)
753 {
754 	struct acpiphp_bridge *bridge = NULL;
755 
756 	acpi_lock_hp_context();
757 	if (adev->hp) {
758 		bridge = to_acpiphp_root_context(adev->hp)->root_bridge;
759 		if (bridge)
760 			get_bridge(bridge);
761 	}
762 	acpi_unlock_hp_context();
763 	if (bridge) {
764 		pci_lock_rescan_remove();
765 
766 		acpiphp_check_bridge(bridge);
767 
768 		pci_unlock_rescan_remove();
769 		put_bridge(bridge);
770 	}
771 }
772 
773 static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot);
774 
775 static void hotplug_event(u32 type, struct acpiphp_context *context)
776 {
777 	acpi_handle handle = context->hp.self->handle;
778 	struct acpiphp_func *func = &context->func;
779 	struct acpiphp_slot *slot = func->slot;
780 	struct acpiphp_bridge *bridge;
781 
782 	acpi_lock_hp_context();
783 	bridge = context->bridge;
784 	if (bridge)
785 		get_bridge(bridge);
786 
787 	acpi_unlock_hp_context();
788 
789 	pci_lock_rescan_remove();
790 
791 	switch (type) {
792 	case ACPI_NOTIFY_BUS_CHECK:
793 		/* bus re-enumerate */
794 		acpi_handle_debug(handle, "Bus check in %s()\n", __func__);
795 		if (bridge)
796 			acpiphp_check_bridge(bridge);
797 		else if (!(slot->flags & SLOT_IS_GOING_AWAY))
798 			enable_slot(slot, false);
799 
800 		break;
801 
802 	case ACPI_NOTIFY_DEVICE_CHECK:
803 		/* device check */
804 		acpi_handle_debug(handle, "Device check in %s()\n", __func__);
805 		if (bridge) {
806 			acpiphp_check_bridge(bridge);
807 		} else if (!(slot->flags & SLOT_IS_GOING_AWAY)) {
808 			/*
809 			 * Check if anything has changed in the slot and rescan
810 			 * from the parent if that's the case.
811 			 */
812 			if (acpiphp_rescan_slot(slot))
813 				acpiphp_check_bridge(func->parent);
814 		}
815 		break;
816 
817 	case ACPI_NOTIFY_EJECT_REQUEST:
818 		/* request device eject */
819 		acpi_handle_debug(handle, "Eject request in %s()\n", __func__);
820 		acpiphp_disable_and_eject_slot(slot);
821 		break;
822 	}
823 
824 	pci_unlock_rescan_remove();
825 	if (bridge)
826 		put_bridge(bridge);
827 }
828 
829 static int acpiphp_hotplug_notify(struct acpi_device *adev, u32 type)
830 {
831 	struct acpiphp_context *context;
832 
833 	context = acpiphp_grab_context(adev);
834 	if (!context)
835 		return -ENODATA;
836 
837 	hotplug_event(type, context);
838 	acpiphp_let_context_go(context);
839 	return 0;
840 }
841 
842 /**
843  * acpiphp_enumerate_slots - Enumerate PCI slots for a given bus.
844  * @bus: PCI bus to enumerate the slots for.
845  *
846  * A "slot" is an object associated with a PCI device number.  All functions
847  * (PCI devices) with the same bus and device number belong to the same slot.
848  */
849 void acpiphp_enumerate_slots(struct pci_bus *bus)
850 {
851 	struct acpiphp_bridge *bridge;
852 	struct acpi_device *adev;
853 	acpi_handle handle;
854 	acpi_status status;
855 
856 	if (acpiphp_disabled)
857 		return;
858 
859 	adev = ACPI_COMPANION(bus->bridge);
860 	if (!adev)
861 		return;
862 
863 	handle = adev->handle;
864 	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
865 	if (!bridge)
866 		return;
867 
868 	INIT_LIST_HEAD(&bridge->slots);
869 	kref_init(&bridge->ref);
870 	bridge->pci_dev = pci_dev_get(bus->self);
871 	bridge->pci_bus = bus;
872 
873 	/*
874 	 * Grab a ref to the subordinate PCI bus in case the bus is
875 	 * removed via PCI core logical hotplug. The ref pins the bus
876 	 * (which we access during module unload).
877 	 */
878 	get_device(&bus->dev);
879 
880 	acpi_lock_hp_context();
881 	if (pci_is_root_bus(bridge->pci_bus)) {
882 		struct acpiphp_root_context *root_context;
883 
884 		root_context = kzalloc(sizeof(*root_context), GFP_KERNEL);
885 		if (!root_context)
886 			goto err;
887 
888 		root_context->root_bridge = bridge;
889 		acpi_set_hp_context(adev, &root_context->hp);
890 	} else {
891 		struct acpiphp_context *context;
892 
893 		/*
894 		 * This bridge should have been registered as a hotplug function
895 		 * under its parent, so the context should be there, unless the
896 		 * parent is going to be handled by pciehp, in which case this
897 		 * bridge is not interesting to us either.
898 		 */
899 		context = acpiphp_get_context(adev);
900 		if (!context)
901 			goto err;
902 
903 		bridge->context = context;
904 		context->bridge = bridge;
905 		/* Get a reference to the parent bridge. */
906 		get_bridge(context->func.parent);
907 	}
908 	acpi_unlock_hp_context();
909 
910 	/* Must be added to the list prior to calling acpiphp_add_context(). */
911 	mutex_lock(&bridge_mutex);
912 	list_add(&bridge->list, &bridge_list);
913 	mutex_unlock(&bridge_mutex);
914 
915 	/* register all slot objects under this bridge */
916 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
917 				     acpiphp_add_context, NULL, bridge, NULL);
918 	if (ACPI_FAILURE(status)) {
919 		acpi_handle_err(handle, "failed to register slots\n");
920 		cleanup_bridge(bridge);
921 		put_bridge(bridge);
922 	}
923 	return;
924 
925  err:
926 	acpi_unlock_hp_context();
927 	put_device(&bus->dev);
928 	pci_dev_put(bridge->pci_dev);
929 	kfree(bridge);
930 }
931 
932 static void acpiphp_drop_bridge(struct acpiphp_bridge *bridge)
933 {
934 	if (pci_is_root_bus(bridge->pci_bus)) {
935 		struct acpiphp_root_context *root_context;
936 		struct acpi_device *adev;
937 
938 		acpi_lock_hp_context();
939 		adev = ACPI_COMPANION(bridge->pci_bus->bridge);
940 		root_context = to_acpiphp_root_context(adev->hp);
941 		adev->hp = NULL;
942 		acpi_unlock_hp_context();
943 		kfree(root_context);
944 	}
945 	cleanup_bridge(bridge);
946 	put_bridge(bridge);
947 }
948 
949 /**
950  * acpiphp_remove_slots - Remove slot objects associated with a given bus.
951  * @bus: PCI bus to remove the slot objects for.
952  */
953 void acpiphp_remove_slots(struct pci_bus *bus)
954 {
955 	struct acpiphp_bridge *bridge;
956 
957 	if (acpiphp_disabled)
958 		return;
959 
960 	mutex_lock(&bridge_mutex);
961 	list_for_each_entry(bridge, &bridge_list, list)
962 		if (bridge->pci_bus == bus) {
963 			mutex_unlock(&bridge_mutex);
964 			acpiphp_drop_bridge(bridge);
965 			return;
966 		}
967 
968 	mutex_unlock(&bridge_mutex);
969 }
970 
971 /**
972  * acpiphp_enable_slot - power on slot
973  * @slot: ACPI PHP slot
974  */
975 int acpiphp_enable_slot(struct acpiphp_slot *slot)
976 {
977 	pci_lock_rescan_remove();
978 
979 	if (slot->flags & SLOT_IS_GOING_AWAY) {
980 		pci_unlock_rescan_remove();
981 		return -ENODEV;
982 	}
983 
984 	/* configure all functions */
985 	if (!(slot->flags & SLOT_ENABLED))
986 		enable_slot(slot, false);
987 
988 	pci_unlock_rescan_remove();
989 	return 0;
990 }
991 
992 /**
993  * acpiphp_disable_and_eject_slot - power off and eject slot
994  * @slot: ACPI PHP slot
995  */
996 static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot)
997 {
998 	struct acpiphp_func *func;
999 
1000 	if (slot->flags & SLOT_IS_GOING_AWAY)
1001 		return -ENODEV;
1002 
1003 	/* unconfigure all functions */
1004 	disable_slot(slot);
1005 
1006 	list_for_each_entry(func, &slot->funcs, sibling)
1007 		if (func->flags & FUNC_HAS_EJ0) {
1008 			acpi_handle handle = func_to_handle(func);
1009 
1010 			if (ACPI_FAILURE(acpi_evaluate_ej0(handle)))
1011 				acpi_handle_err(handle, "_EJ0 failed\n");
1012 
1013 			break;
1014 		}
1015 
1016 	return 0;
1017 }
1018 
1019 int acpiphp_disable_slot(struct acpiphp_slot *slot)
1020 {
1021 	int ret;
1022 
1023 	/*
1024 	 * Acquire acpi_scan_lock to ensure that the execution of _EJ0 in
1025 	 * acpiphp_disable_and_eject_slot() will be synchronized properly.
1026 	 */
1027 	acpi_scan_lock_acquire();
1028 	pci_lock_rescan_remove();
1029 	ret = acpiphp_disable_and_eject_slot(slot);
1030 	pci_unlock_rescan_remove();
1031 	acpi_scan_lock_release();
1032 	return ret;
1033 }
1034 
1035 /*
1036  * slot enabled:  1
1037  * slot disabled: 0
1038  */
1039 u8 acpiphp_get_power_status(struct acpiphp_slot *slot)
1040 {
1041 	return (slot->flags & SLOT_ENABLED);
1042 }
1043 
1044 /*
1045  * latch   open:  1
1046  * latch closed:  0
1047  */
1048 u8 acpiphp_get_latch_status(struct acpiphp_slot *slot)
1049 {
1050 	return !(get_slot_status(slot) & ACPI_STA_DEVICE_UI);
1051 }
1052 
1053 /*
1054  * adapter presence : 1
1055  *          absence : 0
1056  */
1057 u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot)
1058 {
1059 	return !!get_slot_status(slot);
1060 }
1061