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