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32 results

scsi_transport_sas.c

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  • acpiphp_glue.c 25.71 KiB
    // SPDX-License-Identifier: GPL-2.0+
    /*
     * ACPI PCI HotPlug glue functions to ACPI CA subsystem
     *
     * Copyright (C) 2002,2003 Takayoshi Kochi (t-kochi@bq.jp.nec.com)
     * Copyright (C) 2002 Hiroshi Aono (h-aono@ap.jp.nec.com)
     * Copyright (C) 2002,2003 NEC Corporation
     * Copyright (C) 2003-2005 Matthew Wilcox (matthew.wilcox@hp.com)
     * Copyright (C) 2003-2005 Hewlett Packard
     * Copyright (C) 2005 Rajesh Shah (rajesh.shah@intel.com)
     * Copyright (C) 2005 Intel Corporation
     *
     * All rights reserved.
     *
     * Send feedback to <kristen.c.accardi@intel.com>
     *
     */
    
    /*
     * Lifetime rules for pci_dev:
     *  - The one in acpiphp_bridge has its refcount elevated by pci_get_slot()
     *    when the bridge is scanned and it loses a refcount when the bridge
     *    is removed.
     *  - When a P2P bridge is present, we elevate the refcount on the subordinate
     *    bus. It loses the refcount when the the driver unloads.
     */
    
    #define pr_fmt(fmt) "acpiphp_glue: " fmt
    
    #include <linux/module.h>
    
    #include <linux/kernel.h>
    #include <linux/pci.h>
    #include <linux/pci_hotplug.h>
    #include <linux/pci-acpi.h>
    #include <linux/pm_runtime.h>
    #include <linux/mutex.h>
    #include <linux/slab.h>
    #include <linux/acpi.h>
    
    #include "../pci.h"
    #include "acpiphp.h"
    
    static LIST_HEAD(bridge_list);
    static DEFINE_MUTEX(bridge_mutex);
    
    static int acpiphp_hotplug_notify(struct acpi_device *adev, u32 type);
    static void acpiphp_post_dock_fixup(struct acpi_device *adev);
    static void acpiphp_sanitize_bus(struct pci_bus *bus);
    static void hotplug_event(u32 type, struct acpiphp_context *context);
    static void free_bridge(struct kref *kref);
    
    /**
     * acpiphp_init_context - Create hotplug context and grab a reference to it.
     * @adev: ACPI device object to create the context for.
     *
     * Call under acpi_hp_context_lock.
     */
    static struct acpiphp_context *acpiphp_init_context(struct acpi_device *adev)
    {
    	struct acpiphp_context *context;
    
    	context = kzalloc(sizeof(*context), GFP_KERNEL);
    	if (!context)
    		return NULL;
    
    	context->refcount = 1;
    	context->hp.notify = acpiphp_hotplug_notify;
    	context->hp.fixup = acpiphp_post_dock_fixup;
    	acpi_set_hp_context(adev, &context->hp);
    	return context;
    }
    
    /**
     * acpiphp_get_context - Get hotplug context and grab a reference to it.
     * @adev: ACPI device object to get the context for.
     *
     * Call under acpi_hp_context_lock.
     */
    static struct acpiphp_context *acpiphp_get_context(struct acpi_device *adev)
    {
    	struct acpiphp_context *context;
    
    	if (!adev->hp)
    		return NULL;
    
    	context = to_acpiphp_context(adev->hp);
    	context->refcount++;
    	return context;
    }
    
    /**
     * acpiphp_put_context - Drop a reference to ACPI hotplug context.
     * @context: ACPI hotplug context to drop a reference to.
     *
     * The context object is removed if there are no more references to it.
     *
     * Call under acpi_hp_context_lock.
     */
    static void acpiphp_put_context(struct acpiphp_context *context)
    {
    	if (--context->refcount)
    		return;
    
    	WARN_ON(context->bridge);
    	context->hp.self->hp = NULL;
    	kfree(context);
    }
    
    static inline void get_bridge(struct acpiphp_bridge *bridge)
    {
    	kref_get(&bridge->ref);
    }
    
    static inline void put_bridge(struct acpiphp_bridge *bridge)
    {
    	kref_put(&bridge->ref, free_bridge);
    }
    
    static struct acpiphp_context *acpiphp_grab_context(struct acpi_device *adev)
    {
    	struct acpiphp_context *context;
    
    	acpi_lock_hp_context();
    	context = acpiphp_get_context(adev);
    	if (!context || context->func.parent->is_going_away) {
    		acpi_unlock_hp_context();
    		return NULL;
    	}
    	get_bridge(context->func.parent);
    	acpiphp_put_context(context);
    	acpi_unlock_hp_context();
    	return context;
    }
    
    static void acpiphp_let_context_go(struct acpiphp_context *context)
    {
    	put_bridge(context->func.parent);
    }
    
    static void free_bridge(struct kref *kref)
    {
    	struct acpiphp_context *context;
    	struct acpiphp_bridge *bridge;
    	struct acpiphp_slot *slot, *next;
    	struct acpiphp_func *func, *tmp;
    
    	acpi_lock_hp_context();
    
    	bridge = container_of(kref, struct acpiphp_bridge, ref);
    
    	list_for_each_entry_safe(slot, next, &bridge->slots, node) {
    		list_for_each_entry_safe(func, tmp, &slot->funcs, sibling)
    			acpiphp_put_context(func_to_context(func));
    
    		kfree(slot);
    	}
    
    	context = bridge->context;
    	/* Root bridges will not have hotplug context. */
    	if (context) {
    		/* Release the reference taken by acpiphp_enumerate_slots(). */
    		put_bridge(context->func.parent);
    		context->bridge = NULL;
    		acpiphp_put_context(context);
    	}
    
    	put_device(&bridge->pci_bus->dev);
    	pci_dev_put(bridge->pci_dev);
    	kfree(bridge);
    
    	acpi_unlock_hp_context();
    }
    
    /**
     * acpiphp_post_dock_fixup - Post-dock fixups for PCI devices.
     * @adev: ACPI device object corresponding to a PCI device.
     *
     * TBD - figure out a way to only call fixups for systems that require them.
     */
    static void acpiphp_post_dock_fixup(struct acpi_device *adev)
    {
    	struct acpiphp_context *context = acpiphp_grab_context(adev);
    	struct pci_bus *bus;
    	u32 buses;
    
    	if (!context)
    		return;
    
    	bus = context->func.slot->bus;
    	if (!bus->self)
    		goto out;
    
    	/* fixup bad _DCK function that rewrites
    	 * secondary bridge on slot
    	 */
    	pci_read_config_dword(bus->self, PCI_PRIMARY_BUS, &buses);
    
    	if (((buses >> 8) & 0xff) != bus->busn_res.start) {
    		buses = (buses & 0xff000000)
    			| ((unsigned int)(bus->primary)     <<  0)
    			| ((unsigned int)(bus->busn_res.start)   <<  8)
    			| ((unsigned int)(bus->busn_res.end) << 16);
    		pci_write_config_dword(bus->self, PCI_PRIMARY_BUS, buses);
    	}
    
     out:
    	acpiphp_let_context_go(context);
    }
    
    /**
     * acpiphp_add_context - Add ACPIPHP context to an ACPI device object.
     * @handle: ACPI handle of the object to add a context to.
     * @lvl: Not used.
     * @data: The object's parent ACPIPHP bridge.
     * @rv: Not used.
     */
    static acpi_status acpiphp_add_context(acpi_handle handle, u32 lvl, void *data,
    				       void **rv)
    {
    	struct acpiphp_bridge *bridge = data;
    	struct acpiphp_context *context;
    	struct acpi_device *adev;
    	struct acpiphp_slot *slot;
    	struct acpiphp_func *newfunc;
    	acpi_status status = AE_OK;
    	unsigned long long adr;
    	int device, function;
    	struct pci_bus *pbus = bridge->pci_bus;
    	struct pci_dev *pdev = bridge->pci_dev;
    	u32 val;
    
    	status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
    	if (ACPI_FAILURE(status)) {
    		if (status != AE_NOT_FOUND)
    			acpi_handle_warn(handle,
    				"can't evaluate _ADR (%#x)\n", status);
    		return AE_OK;
    	}
    	if (acpi_bus_get_device(handle, &adev))
    		return AE_OK;
    
    	device = (adr >> 16) & 0xffff;
    	function = adr & 0xffff;
    
    	acpi_lock_hp_context();
    	context = acpiphp_init_context(adev);
    	if (!context) {
    		acpi_unlock_hp_context();
    		acpi_handle_err(handle, "No hotplug context\n");
    		return AE_NOT_EXIST;
    	}
    	newfunc = &context->func;
    	newfunc->function = function;
    	newfunc->parent = bridge;
    	acpi_unlock_hp_context();
    
    	/*
    	 * If this is a dock device, its _EJ0 should be executed by the dock
    	 * notify handler after calling _DCK.
    	 */
    	if (!is_dock_device(adev) && acpi_has_method(handle, "_EJ0"))
    		newfunc->flags = FUNC_HAS_EJ0;
    
    	if (acpi_has_method(handle, "_STA"))
    		newfunc->flags |= FUNC_HAS_STA;
    
    	/* search for objects that share the same slot */
    	list_for_each_entry(slot, &bridge->slots, node)
    		if (slot->device == device)
    			goto slot_found;
    
    	slot = kzalloc(sizeof(struct acpiphp_slot), GFP_KERNEL);
    	if (!slot) {
    		acpi_lock_hp_context();
    		acpiphp_put_context(context);
    		acpi_unlock_hp_context();
    		return AE_NO_MEMORY;
    	}
    
    	slot->bus = bridge->pci_bus;
    	slot->device = device;
    	INIT_LIST_HEAD(&slot->funcs);
    
    	list_add_tail(&slot->node, &bridge->slots);
    
    	/*
    	 * Expose slots to user space for functions that have _EJ0 or _RMV or
    	 * are located in dock stations.  Do not expose them for devices handled
    	 * by the native PCIe hotplug (PCIeHP) or standard PCI hotplug
    	 * (SHPCHP), because that code is supposed to expose slots to user
    	 * space in those cases.
    	 */
    	if ((acpi_pci_check_ejectable(pbus, handle) || is_dock_device(adev))
    	    && !(pdev && hotplug_is_native(pdev))) {
    		unsigned long long sun;
    		int retval;
    
    		bridge->nr_slots++;
    		status = acpi_evaluate_integer(handle, "_SUN", NULL, &sun);
    		if (ACPI_FAILURE(status))
    			sun = bridge->nr_slots;
    
    		pr_debug("found ACPI PCI Hotplug slot %llu at PCI %04x:%02x:%02x\n",
    		    sun, pci_domain_nr(pbus), pbus->number, device);
    
    		retval = acpiphp_register_hotplug_slot(slot, sun);
    		if (retval) {
    			slot->slot = NULL;
    			bridge->nr_slots--;
    			if (retval == -EBUSY)
    				pr_warn("Slot %llu already registered by another hotplug driver\n", sun);
    			else
    				pr_warn("acpiphp_register_hotplug_slot failed (err code = 0x%x)\n", retval);
    		}
    		/* Even if the slot registration fails, we can still use it. */
    	}
    
     slot_found:
    	newfunc->slot = slot;
    	list_add_tail(&newfunc->sibling, &slot->funcs);
    
    	if (pci_bus_read_dev_vendor_id(pbus, PCI_DEVFN(device, function),
    				       &val, 60*1000))
    		slot->flags |= SLOT_ENABLED;
    
    	return AE_OK;
    }
    
    static void cleanup_bridge(struct acpiphp_bridge *bridge)
    {
    	struct acpiphp_slot *slot;
    	struct acpiphp_func *func;
    
    	list_for_each_entry(slot, &bridge->slots, node) {
    		list_for_each_entry(func, &slot->funcs, sibling) {
    			struct acpi_device *adev = func_to_acpi_device(func);
    
    			acpi_lock_hp_context();
    			adev->hp->notify = NULL;
    			adev->hp->fixup = NULL;
    			acpi_unlock_hp_context();
    		}
    		slot->flags |= SLOT_IS_GOING_AWAY;
    		if (slot->slot)
    			acpiphp_unregister_hotplug_slot(slot);
    	}
    
    	mutex_lock(&bridge_mutex);
    	list_del(&bridge->list);
    	mutex_unlock(&bridge_mutex);
    
    	acpi_lock_hp_context();
    	bridge->is_going_away = true;
    	acpi_unlock_hp_context();
    }
    
    /**
     * acpiphp_max_busnr - return the highest reserved bus number under the given bus.
     * @bus: bus to start search with
     */
    static unsigned char acpiphp_max_busnr(struct pci_bus *bus)
    {
    	struct pci_bus *tmp;
    	unsigned char max, n;
    
    	/*
    	 * pci_bus_max_busnr will return the highest
    	 * reserved busnr for all these children.
    	 * that is equivalent to the bus->subordinate
    	 * value.  We don't want to use the parent's
    	 * bus->subordinate value because it could have
    	 * padding in it.
    	 */
    	max = bus->busn_res.start;
    
    	list_for_each_entry(tmp, &bus->children, node) {
    		n = pci_bus_max_busnr(tmp);
    		if (n > max)
    			max = n;
    	}
    	return max;
    }
    
    static void acpiphp_set_acpi_region(struct acpiphp_slot *slot)
    {
    	struct acpiphp_func *func;
    	union acpi_object params[2];
    	struct acpi_object_list arg_list;
    
    	list_for_each_entry(func, &slot->funcs, sibling) {
    		arg_list.count = 2;
    		arg_list.pointer = params;
    		params[0].type = ACPI_TYPE_INTEGER;
    		params[0].integer.value = ACPI_ADR_SPACE_PCI_CONFIG;
    		params[1].type = ACPI_TYPE_INTEGER;
    		params[1].integer.value = 1;
    		/* _REG is optional, we don't care about if there is failure */
    		acpi_evaluate_object(func_to_handle(func), "_REG", &arg_list,
    				     NULL);
    	}
    }
    
    static void check_hotplug_bridge(struct acpiphp_slot *slot, struct pci_dev *dev)
    {
    	struct acpiphp_func *func;
    
    	/* quirk, or pcie could set it already */
    	if (dev->is_hotplug_bridge)
    		return;
    
    	list_for_each_entry(func, &slot->funcs, sibling) {
    		if (PCI_FUNC(dev->devfn) == func->function) {
    			dev->is_hotplug_bridge = 1;
    			break;
    		}
    	}
    }
    
    static int acpiphp_rescan_slot(struct acpiphp_slot *slot)
    {
    	struct acpiphp_func *func;
    
    	list_for_each_entry(func, &slot->funcs, sibling) {
    		struct acpi_device *adev = func_to_acpi_device(func);
    
    		acpi_bus_scan(adev->handle);
    		if (acpi_device_enumerated(adev))
    			acpi_device_set_power(adev, ACPI_STATE_D0);
    	}
    	return pci_scan_slot(slot->bus, PCI_DEVFN(slot->device, 0));
    }
    
    static void acpiphp_native_scan_bridge(struct pci_dev *bridge)
    {
    	struct pci_bus *bus = bridge->subordinate;
    	struct pci_dev *dev;
    	int max;
    
    	if (!bus)
    		return;
    
    	max = bus->busn_res.start;
    	/* Scan already configured non-hotplug bridges */
    	for_each_pci_bridge(dev, bus) {
    		if (!hotplug_is_native(dev))
    			max = pci_scan_bridge(bus, dev, max, 0);
    	}
    
    	/* Scan non-hotplug bridges that need to be reconfigured */
    	for_each_pci_bridge(dev, bus) {
    		if (!hotplug_is_native(dev))
    			max = pci_scan_bridge(bus, dev, max, 1);
    	}
    }
    
    /**
     * enable_slot - enable, configure a slot
     * @slot: slot to be enabled
     *
     * This function should be called per *physical slot*,
     * not per each slot object in ACPI namespace.
     */
    static void enable_slot(struct acpiphp_slot *slot)
    {
    	struct pci_dev *dev;
    	struct pci_bus *bus = slot->bus;
    	struct acpiphp_func *func;
    
    	if (bus->self && hotplug_is_native(bus->self)) {
    		/*
    		 * If native hotplug is used, it will take care of hotplug
    		 * slot management and resource allocation for hotplug
    		 * bridges. However, ACPI hotplug may still be used for
    		 * non-hotplug bridges to bring in additional devices such
    		 * as a Thunderbolt host controller.
    		 */
    		for_each_pci_bridge(dev, bus) {
    			if (PCI_SLOT(dev->devfn) == slot->device)
    				acpiphp_native_scan_bridge(dev);
    		}
    		pci_assign_unassigned_bridge_resources(bus->self);
    	} else {
    		LIST_HEAD(add_list);
    		int max, pass;
    
    		acpiphp_rescan_slot(slot);
    		max = acpiphp_max_busnr(bus);
    		for (pass = 0; pass < 2; pass++) {
    			for_each_pci_bridge(dev, bus) {
    				if (PCI_SLOT(dev->devfn) != slot->device)
    					continue;
    
    				max = pci_scan_bridge(bus, dev, max, pass);
    				if (pass && dev->subordinate) {
    					check_hotplug_bridge(slot, dev);
    					pcibios_resource_survey_bus(dev->subordinate);
    					__pci_bus_size_bridges(dev->subordinate,
    							       &add_list);
    				}
    			}
    		}
    		__pci_bus_assign_resources(bus, &add_list, NULL);
    	}
    
    	acpiphp_sanitize_bus(bus);
    	pcie_bus_configure_settings(bus);
    	acpiphp_set_acpi_region(slot);
    
    	list_for_each_entry(dev, &bus->devices, bus_list) {
    		/* Assume that newly added devices are powered on already. */
    		if (!dev->is_added)
    			dev->current_state = PCI_D0;
    	}
    
    	pci_bus_add_devices(bus);
    
    	slot->flags |= SLOT_ENABLED;
    	list_for_each_entry(func, &slot->funcs, sibling) {
    		dev = pci_get_slot(bus, PCI_DEVFN(slot->device,
    						  func->function));
    		if (!dev) {
    			/* Do not set SLOT_ENABLED flag if some funcs
    			   are not added. */
    			slot->flags &= (~SLOT_ENABLED);
    			continue;
    		}
    	}
    }
    
    /**
     * disable_slot - disable a slot
     * @slot: ACPI PHP slot
     */
    static void disable_slot(struct acpiphp_slot *slot)
    {
    	struct pci_bus *bus = slot->bus;
    	struct pci_dev *dev, *prev;
    	struct acpiphp_func *func;
    
    	/*
    	 * enable_slot() enumerates all functions in this device via
    	 * pci_scan_slot(), whether they have associated ACPI hotplug
    	 * methods (_EJ0, etc.) or not.  Therefore, we remove all functions
    	 * here.
    	 */
    	list_for_each_entry_safe_reverse(dev, prev, &bus->devices, bus_list)
    		if (PCI_SLOT(dev->devfn) == slot->device)
    			pci_stop_and_remove_bus_device(dev);
    
    	list_for_each_entry(func, &slot->funcs, sibling)
    		acpi_bus_trim(func_to_acpi_device(func));
    
    	slot->flags &= (~SLOT_ENABLED);
    }
    
    static bool slot_no_hotplug(struct acpiphp_slot *slot)
    {
    	struct pci_bus *bus = slot->bus;
    	struct pci_dev *dev;
    
    	list_for_each_entry(dev, &bus->devices, bus_list) {
    		if (PCI_SLOT(dev->devfn) == slot->device && dev->ignore_hotplug)
    			return true;
    	}
    	return false;
    }
    
    /**
     * get_slot_status - get ACPI slot status
     * @slot: ACPI PHP slot
     *
     * If a slot has _STA for each function and if any one of them
     * returned non-zero status, return it.
     *
     * If a slot doesn't have _STA and if any one of its functions'
     * configuration space is configured, return 0x0f as a _STA.
     *
     * Otherwise return 0.
     */
    static unsigned int get_slot_status(struct acpiphp_slot *slot)
    {
    	unsigned long long sta = 0;
    	struct acpiphp_func *func;
    	u32 dvid;
    
    	list_for_each_entry(func, &slot->funcs, sibling) {
    		if (func->flags & FUNC_HAS_STA) {
    			acpi_status status;
    
    			status = acpi_evaluate_integer(func_to_handle(func),
    						       "_STA", NULL, &sta);
    			if (ACPI_SUCCESS(status) && sta)
    				break;
    		} else {
    			if (pci_bus_read_dev_vendor_id(slot->bus,
    					PCI_DEVFN(slot->device, func->function),
    					&dvid, 0)) {
    				sta = ACPI_STA_ALL;
    				break;
    			}
    		}
    	}
    
    	if (!sta) {
    		/*
    		 * Check for the slot itself since it may be that the
    		 * ACPI slot is a device below PCIe upstream port so in
    		 * that case it may not even be reachable yet.
    		 */
    		if (pci_bus_read_dev_vendor_id(slot->bus,
    				PCI_DEVFN(slot->device, 0), &dvid, 0)) {
    			sta = ACPI_STA_ALL;
    		}
    	}
    
    	return (unsigned int)sta;
    }
    
    static inline bool device_status_valid(unsigned int sta)
    {
    	/*
    	 * ACPI spec says that _STA may return bit 0 clear with bit 3 set
    	 * if the device is valid but does not require a device driver to be
    	 * loaded (Section 6.3.7 of ACPI 5.0A).
    	 */
    	unsigned int mask = ACPI_STA_DEVICE_ENABLED | ACPI_STA_DEVICE_FUNCTIONING;
    	return (sta & mask) == mask;
    }
    
    /**
     * trim_stale_devices - remove PCI devices that are not responding.
     * @dev: PCI device to start walking the hierarchy from.
     */
    static void trim_stale_devices(struct pci_dev *dev)
    {
    	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
    	struct pci_bus *bus = dev->subordinate;
    	bool alive = dev->ignore_hotplug;
    
    	if (adev) {
    		acpi_status status;
    		unsigned long long sta;
    
    		status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
    		alive = alive || (ACPI_SUCCESS(status) && device_status_valid(sta));
    	}
    	if (!alive)
    		alive = pci_device_is_present(dev);
    
    	if (!alive) {
    		pci_stop_and_remove_bus_device(dev);
    		if (adev)
    			acpi_bus_trim(adev);
    	} else if (bus) {
    		struct pci_dev *child, *tmp;
    
    		/* The device is a bridge. so check the bus below it. */
    		pm_runtime_get_sync(&dev->dev);
    		list_for_each_entry_safe_reverse(child, tmp, &bus->devices, bus_list)
    			trim_stale_devices(child);
    
    		pm_runtime_put(&dev->dev);
    	}
    }
    
    /**
     * acpiphp_check_bridge - re-enumerate devices
     * @bridge: where to begin re-enumeration
     *
     * Iterate over all slots under this bridge and make sure that if a
     * card is present they are enabled, and if not they are disabled.
     */
    static void acpiphp_check_bridge(struct acpiphp_bridge *bridge)
    {
    	struct acpiphp_slot *slot;
    
    	/* Bail out if the bridge is going away. */
    	if (bridge->is_going_away)
    		return;
    
    	if (bridge->pci_dev)
    		pm_runtime_get_sync(&bridge->pci_dev->dev);
    
    	list_for_each_entry(slot, &bridge->slots, node) {
    		struct pci_bus *bus = slot->bus;
    		struct pci_dev *dev, *tmp;
    
    		if (slot_no_hotplug(slot)) {
    			; /* do nothing */
    		} else if (device_status_valid(get_slot_status(slot))) {
    			/* remove stale devices if any */
    			list_for_each_entry_safe_reverse(dev, tmp,
    							 &bus->devices, bus_list)
    				if (PCI_SLOT(dev->devfn) == slot->device)
    					trim_stale_devices(dev);
    
    			/* configure all functions */
    			enable_slot(slot);
    		} else {
    			disable_slot(slot);
    		}
    	}
    
    	if (bridge->pci_dev)
    		pm_runtime_put(&bridge->pci_dev->dev);
    }
    
    /*
     * Remove devices for which we could not assign resources, call
     * arch specific code to fix-up the bus
     */
    static void acpiphp_sanitize_bus(struct pci_bus *bus)
    {
    	struct pci_dev *dev, *tmp;
    	int i;
    	unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM;
    
    	list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) {
    		for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) {
    			struct resource *res = &dev->resource[i];
    			if ((res->flags & type_mask) && !res->start &&
    					res->end) {
    				/* Could not assign a required resources
    				 * for this device, remove it */
    				pci_stop_and_remove_bus_device(dev);
    				break;
    			}
    		}
    	}
    }
    
    /*
     * ACPI event handlers
     */
    
    void acpiphp_check_host_bridge(struct acpi_device *adev)
    {
    	struct acpiphp_bridge *bridge = NULL;
    
    	acpi_lock_hp_context();
    	if (adev->hp) {
    		bridge = to_acpiphp_root_context(adev->hp)->root_bridge;
    		if (bridge)
    			get_bridge(bridge);
    	}
    	acpi_unlock_hp_context();
    	if (bridge) {
    		pci_lock_rescan_remove();
    
    		acpiphp_check_bridge(bridge);
    
    		pci_unlock_rescan_remove();
    		put_bridge(bridge);
    	}
    }
    
    static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot);
    
    static void hotplug_event(u32 type, struct acpiphp_context *context)
    {
    	acpi_handle handle = context->hp.self->handle;
    	struct acpiphp_func *func = &context->func;
    	struct acpiphp_slot *slot = func->slot;
    	struct acpiphp_bridge *bridge;
    
    	acpi_lock_hp_context();
    	bridge = context->bridge;
    	if (bridge)
    		get_bridge(bridge);
    
    	acpi_unlock_hp_context();
    
    	pci_lock_rescan_remove();
    
    	switch (type) {
    	case ACPI_NOTIFY_BUS_CHECK:
    		/* bus re-enumerate */
    		acpi_handle_debug(handle, "Bus check in %s()\n", __func__);
    		if (bridge)
    			acpiphp_check_bridge(bridge);
    		else if (!(slot->flags & SLOT_IS_GOING_AWAY))
    			enable_slot(slot);
    
    		break;
    
    	case ACPI_NOTIFY_DEVICE_CHECK:
    		/* device check */
    		acpi_handle_debug(handle, "Device check in %s()\n", __func__);
    		if (bridge) {
    			acpiphp_check_bridge(bridge);
    		} else if (!(slot->flags & SLOT_IS_GOING_AWAY)) {
    			/*
    			 * Check if anything has changed in the slot and rescan
    			 * from the parent if that's the case.
    			 */
    			if (acpiphp_rescan_slot(slot))
    				acpiphp_check_bridge(func->parent);
    		}
    		break;
    
    	case ACPI_NOTIFY_EJECT_REQUEST:
    		/* request device eject */
    		acpi_handle_debug(handle, "Eject request in %s()\n", __func__);
    		acpiphp_disable_and_eject_slot(slot);
    		break;
    	}
    
    	pci_unlock_rescan_remove();
    	if (bridge)
    		put_bridge(bridge);
    }
    
    static int acpiphp_hotplug_notify(struct acpi_device *adev, u32 type)
    {
    	struct acpiphp_context *context;
    
    	context = acpiphp_grab_context(adev);
    	if (!context)
    		return -ENODATA;
    
    	hotplug_event(type, context);
    	acpiphp_let_context_go(context);
    	return 0;
    }
    
    /**
     * acpiphp_enumerate_slots - Enumerate PCI slots for a given bus.
     * @bus: PCI bus to enumerate the slots for.
     *
     * A "slot" is an object associated with a PCI device number.  All functions
     * (PCI devices) with the same bus and device number belong to the same slot.
     */
    void acpiphp_enumerate_slots(struct pci_bus *bus)
    {
    	struct acpiphp_bridge *bridge;
    	struct acpi_device *adev;
    	acpi_handle handle;
    	acpi_status status;
    
    	if (acpiphp_disabled)
    		return;
    
    	adev = ACPI_COMPANION(bus->bridge);
    	if (!adev)
    		return;
    
    	handle = adev->handle;
    	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
    	if (!bridge)
    		return;
    
    	INIT_LIST_HEAD(&bridge->slots);
    	kref_init(&bridge->ref);
    	bridge->pci_dev = pci_dev_get(bus->self);
    	bridge->pci_bus = bus;
    
    	/*
    	 * Grab a ref to the subordinate PCI bus in case the bus is
    	 * removed via PCI core logical hotplug. The ref pins the bus
    	 * (which we access during module unload).
    	 */
    	get_device(&bus->dev);
    
    	acpi_lock_hp_context();
    	if (pci_is_root_bus(bridge->pci_bus)) {
    		struct acpiphp_root_context *root_context;
    
    		root_context = kzalloc(sizeof(*root_context), GFP_KERNEL);
    		if (!root_context)
    			goto err;
    
    		root_context->root_bridge = bridge;
    		acpi_set_hp_context(adev, &root_context->hp);
    	} else {
    		struct acpiphp_context *context;
    
    		/*
    		 * This bridge should have been registered as a hotplug function
    		 * under its parent, so the context should be there, unless the
    		 * parent is going to be handled by pciehp, in which case this
    		 * bridge is not interesting to us either.
    		 */
    		context = acpiphp_get_context(adev);
    		if (!context)
    			goto err;
    
    		bridge->context = context;
    		context->bridge = bridge;
    		/* Get a reference to the parent bridge. */
    		get_bridge(context->func.parent);
    	}
    	acpi_unlock_hp_context();
    
    	/* Must be added to the list prior to calling acpiphp_add_context(). */
    	mutex_lock(&bridge_mutex);
    	list_add(&bridge->list, &bridge_list);
    	mutex_unlock(&bridge_mutex);
    
    	/* register all slot objects under this bridge */
    	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
    				     acpiphp_add_context, NULL, bridge, NULL);
    	if (ACPI_FAILURE(status)) {
    		acpi_handle_err(handle, "failed to register slots\n");
    		cleanup_bridge(bridge);
    		put_bridge(bridge);
    	}
    	return;
    
     err:
    	acpi_unlock_hp_context();
    	put_device(&bus->dev);
    	pci_dev_put(bridge->pci_dev);
    	kfree(bridge);
    }
    
    static void acpiphp_drop_bridge(struct acpiphp_bridge *bridge)
    {
    	if (pci_is_root_bus(bridge->pci_bus)) {
    		struct acpiphp_root_context *root_context;
    		struct acpi_device *adev;
    
    		acpi_lock_hp_context();
    		adev = ACPI_COMPANION(bridge->pci_bus->bridge);
    		root_context = to_acpiphp_root_context(adev->hp);
    		adev->hp = NULL;
    		acpi_unlock_hp_context();
    		kfree(root_context);
    	}
    	cleanup_bridge(bridge);
    	put_bridge(bridge);
    }
    
    /**
     * acpiphp_remove_slots - Remove slot objects associated with a given bus.
     * @bus: PCI bus to remove the slot objects for.
     */
    void acpiphp_remove_slots(struct pci_bus *bus)
    {
    	struct acpiphp_bridge *bridge;
    
    	if (acpiphp_disabled)
    		return;
    
    	mutex_lock(&bridge_mutex);
    	list_for_each_entry(bridge, &bridge_list, list)
    		if (bridge->pci_bus == bus) {
    			mutex_unlock(&bridge_mutex);
    			acpiphp_drop_bridge(bridge);
    			return;
    		}
    
    	mutex_unlock(&bridge_mutex);
    }
    
    /**
     * acpiphp_enable_slot - power on slot
     * @slot: ACPI PHP slot
     */
    int acpiphp_enable_slot(struct acpiphp_slot *slot)
    {
    	pci_lock_rescan_remove();
    
    	if (slot->flags & SLOT_IS_GOING_AWAY) {
    		pci_unlock_rescan_remove();
    		return -ENODEV;
    	}
    
    	/* configure all functions */
    	if (!(slot->flags & SLOT_ENABLED))
    		enable_slot(slot);
    
    	pci_unlock_rescan_remove();
    	return 0;
    }
    
    /**
     * acpiphp_disable_and_eject_slot - power off and eject slot
     * @slot: ACPI PHP slot
     */
    static int acpiphp_disable_and_eject_slot(struct acpiphp_slot *slot)
    {
    	struct acpiphp_func *func;
    
    	if (slot->flags & SLOT_IS_GOING_AWAY)
    		return -ENODEV;
    
    	/* unconfigure all functions */
    	disable_slot(slot);
    
    	list_for_each_entry(func, &slot->funcs, sibling)
    		if (func->flags & FUNC_HAS_EJ0) {
    			acpi_handle handle = func_to_handle(func);
    
    			if (ACPI_FAILURE(acpi_evaluate_ej0(handle)))
    				acpi_handle_err(handle, "_EJ0 failed\n");
    
    			break;
    		}
    
    	return 0;
    }
    
    int acpiphp_disable_slot(struct acpiphp_slot *slot)
    {
    	int ret;
    
    	/*
    	 * Acquire acpi_scan_lock to ensure that the execution of _EJ0 in
    	 * acpiphp_disable_and_eject_slot() will be synchronized properly.
    	 */
    	acpi_scan_lock_acquire();
    	pci_lock_rescan_remove();
    	ret = acpiphp_disable_and_eject_slot(slot);
    	pci_unlock_rescan_remove();
    	acpi_scan_lock_release();
    	return ret;
    }
    
    /*
     * slot enabled:  1
     * slot disabled: 0
     */
    u8 acpiphp_get_power_status(struct acpiphp_slot *slot)
    {
    	return (slot->flags & SLOT_ENABLED);
    }
    
    /*
     * latch   open:  1
     * latch closed:  0
     */
    u8 acpiphp_get_latch_status(struct acpiphp_slot *slot)
    {
    	return !(get_slot_status(slot) & ACPI_STA_DEVICE_UI);
    }
    
    /*
     * adapter presence : 1
     *          absence : 0
     */
    u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot)
    {
    	return !!get_slot_status(slot);
    }