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