Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2291 insertions, 0 deletions

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
new file mode 100644
index 000000000..16d291e10
--- /dev/null
+++ b/drivers/pci/setup-bus.c
@@ -0,0 +1,2291 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support routines for initializing a PCI subsystem
+ *
+ * Extruded from code written by
+ *      Dave Rusling (david.rusling@reo.mts.dec.com)
+ *      David Mosberger (davidm@cs.arizona.edu)
+ *	David Miller (davem@redhat.com)
+ *
+ * Nov 2000, Ivan Kokshaysky <ink@jurassic.park.msu.ru>
+ *	     PCI-PCI bridges cleanup, sorted resource allocation.
+ * Feb 2002, Ivan Kokshaysky <ink@jurassic.park.msu.ru>
+ *	     Converted to allocation in 3 passes, which gives
+ *	     tighter packing. Prefetchable range support.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/cache.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include "pci.h"
+
+unsigned int pci_flags;
+EXPORT_SYMBOL_GPL(pci_flags);
+
+struct pci_dev_resource {
+	struct list_head list;
+	struct resource *res;
+	struct pci_dev *dev;
+	resource_size_t start;
+	resource_size_t end;
+	resource_size_t add_size;
+	resource_size_t min_align;
+	unsigned long flags;
+};
+
+static void free_list(struct list_head *head)
+{
+	struct pci_dev_resource *dev_res, *tmp;
+
+	list_for_each_entry_safe(dev_res, tmp, head, list) {
+		list_del(&dev_res->list);
+		kfree(dev_res);
+	}
+}
+
+/**
+ * add_to_list() - Add a new resource tracker to the list
+ * @head:	Head of the list
+ * @dev:	Device to which the resource belongs
+ * @res:	Resource to be tracked
+ * @add_size:	Additional size to be optionally added to the resource
+ * @min_align:	Minimum memory window alignment
+ */
+static int add_to_list(struct list_head *head, struct pci_dev *dev,
+		       struct resource *res, resource_size_t add_size,
+		       resource_size_t min_align)
+{
+	struct pci_dev_resource *tmp;
+
+	tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	tmp->res = res;
+	tmp->dev = dev;
+	tmp->start = res->start;
+	tmp->end = res->end;
+	tmp->flags = res->flags;
+	tmp->add_size = add_size;
+	tmp->min_align = min_align;
+
+	list_add(&tmp->list, head);
+
+	return 0;
+}
+
+static void remove_from_list(struct list_head *head, struct resource *res)
+{
+	struct pci_dev_resource *dev_res, *tmp;
+
+	list_for_each_entry_safe(dev_res, tmp, head, list) {
+		if (dev_res->res == res) {
+			list_del(&dev_res->list);
+			kfree(dev_res);
+			break;
+		}
+	}
+}
+
+static struct pci_dev_resource *res_to_dev_res(struct list_head *head,
+					       struct resource *res)
+{
+	struct pci_dev_resource *dev_res;
+
+	list_for_each_entry(dev_res, head, list) {
+		if (dev_res->res == res)
+			return dev_res;
+	}
+
+	return NULL;
+}
+
+static resource_size_t get_res_add_size(struct list_head *head,
+					struct resource *res)
+{
+	struct pci_dev_resource *dev_res;
+
+	dev_res = res_to_dev_res(head, res);
+	return dev_res ? dev_res->add_size : 0;
+}
+
+static resource_size_t get_res_add_align(struct list_head *head,
+					 struct resource *res)
+{
+	struct pci_dev_resource *dev_res;
+
+	dev_res = res_to_dev_res(head, res);
+	return dev_res ? dev_res->min_align : 0;
+}
+
+
+/* Sort resources by alignment */
+static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
+{
+	int i;
+
+	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+		struct resource *r;
+		struct pci_dev_resource *dev_res, *tmp;
+		resource_size_t r_align;
+		struct list_head *n;
+
+		r = &dev->resource[i];
+
+		if (r->flags & IORESOURCE_PCI_FIXED)
+			continue;
+
+		if (!(r->flags) || r->parent)
+			continue;
+
+		r_align = pci_resource_alignment(dev, r);
+		if (!r_align) {
+			pci_warn(dev, "BAR %d: %pR has bogus alignment\n",
+				 i, r);
+			continue;
+		}
+
+		tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
+		if (!tmp)
+			panic("%s: kzalloc() failed!\n", __func__);
+		tmp->res = r;
+		tmp->dev = dev;
+
+		/* Fallback is smallest one or list is empty */
+		n = head;
+		list_for_each_entry(dev_res, head, list) {
+			resource_size_t align;
+
+			align = pci_resource_alignment(dev_res->dev,
+							 dev_res->res);
+
+			if (r_align > align) {
+				n = &dev_res->list;
+				break;
+			}
+		}
+		/* Insert it just before n */
+		list_add_tail(&tmp->list, n);
+	}
+}
+
+static void __dev_sort_resources(struct pci_dev *dev, struct list_head *head)
+{
+	u16 class = dev->class >> 8;
+
+	/* Don't touch classless devices or host bridges or IOAPICs */
+	if (class == PCI_CLASS_NOT_DEFINED || class == PCI_CLASS_BRIDGE_HOST)
+		return;
+
+	/* Don't touch IOAPIC devices already enabled by firmware */
+	if (class == PCI_CLASS_SYSTEM_PIC) {
+		u16 command;
+		pci_read_config_word(dev, PCI_COMMAND, &command);
+		if (command & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY))
+			return;
+	}
+
+	pdev_sort_resources(dev, head);
+}
+
+static inline void reset_resource(struct resource *res)
+{
+	res->start = 0;
+	res->end = 0;
+	res->flags = 0;
+}
+
+/**
+ * reassign_resources_sorted() - Satisfy any additional resource requests
+ *
+ * @realloc_head:	Head of the list tracking requests requiring
+ *			additional resources
+ * @head:		Head of the list tracking requests with allocated
+ *			resources
+ *
+ * Walk through each element of the realloc_head and try to procure additional
+ * resources for the element, provided the element is in the head list.
+ */
+static void reassign_resources_sorted(struct list_head *realloc_head,
+				      struct list_head *head)
+{
+	struct resource *res;
+	struct pci_dev_resource *add_res, *tmp;
+	struct pci_dev_resource *dev_res;
+	resource_size_t add_size, align;
+	int idx;
+
+	list_for_each_entry_safe(add_res, tmp, realloc_head, list) {
+		bool found_match = false;
+
+		res = add_res->res;
+		/* Skip resource that has been reset */
+		if (!res->flags)
+			goto out;
+
+		/* Skip this resource if not found in head list */
+		list_for_each_entry(dev_res, head, list) {
+			if (dev_res->res == res) {
+				found_match = true;
+				break;
+			}
+		}
+		if (!found_match) /* Just skip */
+			continue;
+
+		idx = res - &add_res->dev->resource[0];
+		add_size = add_res->add_size;
+		align = add_res->min_align;
+		if (!resource_size(res)) {
+			res->start = align;
+			res->end = res->start + add_size - 1;
+			if (pci_assign_resource(add_res->dev, idx))
+				reset_resource(res);
+		} else {
+			res->flags |= add_res->flags &
+				 (IORESOURCE_STARTALIGN|IORESOURCE_SIZEALIGN);
+			if (pci_reassign_resource(add_res->dev, idx,
+						  add_size, align))
+				pci_info(add_res->dev, "failed to add %llx res[%d]=%pR\n",
+					 (unsigned long long) add_size, idx,
+					 res);
+		}
+out:
+		list_del(&add_res->list);
+		kfree(add_res);
+	}
+}
+
+/**
+ * assign_requested_resources_sorted() - Satisfy resource requests
+ *
+ * @head:	Head of the list tracking requests for resources
+ * @fail_head:	Head of the list tracking requests that could not be
+ *		allocated
+ *
+ * Satisfy resource requests of each element in the list.  Add requests that
+ * could not be satisfied to the failed_list.
+ */
+static void assign_requested_resources_sorted(struct list_head *head,
+				 struct list_head *fail_head)
+{
+	struct resource *res;
+	struct pci_dev_resource *dev_res;
+	int idx;
+
+	list_for_each_entry(dev_res, head, list) {
+		res = dev_res->res;
+		idx = res - &dev_res->dev->resource[0];
+		if (resource_size(res) &&
+		    pci_assign_resource(dev_res->dev, idx)) {
+			if (fail_head) {
+				/*
+				 * If the failed resource is a ROM BAR and
+				 * it will be enabled later, don't add it
+				 * to the list.
+				 */
+				if (!((idx == PCI_ROM_RESOURCE) &&
+				      (!(res->flags & IORESOURCE_ROM_ENABLE))))
+					add_to_list(fail_head,
+						    dev_res->dev, res,
+						    0 /* don't care */,
+						    0 /* don't care */);
+			}
+			reset_resource(res);
+		}
+	}
+}
+
+static unsigned long pci_fail_res_type_mask(struct list_head *fail_head)
+{
+	struct pci_dev_resource *fail_res;
+	unsigned long mask = 0;
+
+	/* Check failed type */
+	list_for_each_entry(fail_res, fail_head, list)
+		mask |= fail_res->flags;
+
+	/*
+	 * One pref failed resource will set IORESOURCE_MEM, as we can
+	 * allocate pref in non-pref range.  Will release all assigned
+	 * non-pref sibling resources according to that bit.
+	 */
+	return mask & (IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH);
+}
+
+static bool pci_need_to_release(unsigned long mask, struct resource *res)
+{
+	if (res->flags & IORESOURCE_IO)
+		return !!(mask & IORESOURCE_IO);
+
+	/* Check pref at first */
+	if (res->flags & IORESOURCE_PREFETCH) {
+		if (mask & IORESOURCE_PREFETCH)
+			return true;
+		/* Count pref if its parent is non-pref */
+		else if ((mask & IORESOURCE_MEM) &&
+			 !(res->parent->flags & IORESOURCE_PREFETCH))
+			return true;
+		else
+			return false;
+	}
+
+	if (res->flags & IORESOURCE_MEM)
+		return !!(mask & IORESOURCE_MEM);
+
+	return false;	/* Should not get here */
+}
+
+static void __assign_resources_sorted(struct list_head *head,
+				      struct list_head *realloc_head,
+				      struct list_head *fail_head)
+{
+	/*
+	 * Should not assign requested resources at first.  They could be
+	 * adjacent, so later reassign can not reallocate them one by one in
+	 * parent resource window.
+	 *
+	 * Try to assign requested + add_size at beginning.  If could do that,
+	 * could get out early.  If could not do that, we still try to assign
+	 * requested at first, then try to reassign add_size for some resources.
+	 *
+	 * Separate three resource type checking if we need to release
+	 * assigned resource after requested + add_size try.
+	 *
+	 *	1. If IO port assignment fails, will release assigned IO
+	 *	   port.
+	 *	2. If pref MMIO assignment fails, release assigned pref
+	 *	   MMIO.  If assigned pref MMIO's parent is non-pref MMIO
+	 *	   and non-pref MMIO assignment fails, will release that
+	 *	   assigned pref MMIO.
+	 *	3. If non-pref MMIO assignment fails or pref MMIO
+	 *	   assignment fails, will release assigned non-pref MMIO.
+	 */
+	LIST_HEAD(save_head);
+	LIST_HEAD(local_fail_head);
+	struct pci_dev_resource *save_res;
+	struct pci_dev_resource *dev_res, *tmp_res, *dev_res2;
+	unsigned long fail_type;
+	resource_size_t add_align, align;
+
+	/* Check if optional add_size is there */
+	if (!realloc_head || list_empty(realloc_head))
+		goto requested_and_reassign;
+
+	/* Save original start, end, flags etc at first */
+	list_for_each_entry(dev_res, head, list) {
+		if (add_to_list(&save_head, dev_res->dev, dev_res->res, 0, 0)) {
+			free_list(&save_head);
+			goto requested_and_reassign;
+		}
+	}
+
+	/* Update res in head list with add_size in realloc_head list */
+	list_for_each_entry_safe(dev_res, tmp_res, head, list) {
+		dev_res->res->end += get_res_add_size(realloc_head,
+							dev_res->res);
+
+		/*
+		 * There are two kinds of additional resources in the list:
+		 * 1. bridge resource  -- IORESOURCE_STARTALIGN
+		 * 2. SR-IOV resource  -- IORESOURCE_SIZEALIGN
+		 * Here just fix the additional alignment for bridge
+		 */
+		if (!(dev_res->res->flags & IORESOURCE_STARTALIGN))
+			continue;
+
+		add_align = get_res_add_align(realloc_head, dev_res->res);
+
+		/*
+		 * The "head" list is sorted by alignment so resources with
+		 * bigger alignment will be assigned first.  After we
+		 * change the alignment of a dev_res in "head" list, we
+		 * need to reorder the list by alignment to make it
+		 * consistent.
+		 */
+		if (add_align > dev_res->res->start) {
+			resource_size_t r_size = resource_size(dev_res->res);
+
+			dev_res->res->start = add_align;
+			dev_res->res->end = add_align + r_size - 1;
+
+			list_for_each_entry(dev_res2, head, list) {
+				align = pci_resource_alignment(dev_res2->dev,
+							       dev_res2->res);
+				if (add_align > align) {
+					list_move_tail(&dev_res->list,
+						       &dev_res2->list);
+					break;
+				}
+			}
+		}
+
+	}
+
+	/* Try updated head list with add_size added */
+	assign_requested_resources_sorted(head, &local_fail_head);
+
+	/* All assigned with add_size? */
+	if (list_empty(&local_fail_head)) {
+		/* Remove head list from realloc_head list */
+		list_for_each_entry(dev_res, head, list)
+			remove_from_list(realloc_head, dev_res->res);
+		free_list(&save_head);
+		free_list(head);
+		return;
+	}
+
+	/* Check failed type */
+	fail_type = pci_fail_res_type_mask(&local_fail_head);
+	/* Remove not need to be released assigned res from head list etc */
+	list_for_each_entry_safe(dev_res, tmp_res, head, list)
+		if (dev_res->res->parent &&
+		    !pci_need_to_release(fail_type, dev_res->res)) {
+			/* Remove it from realloc_head list */
+			remove_from_list(realloc_head, dev_res->res);
+			remove_from_list(&save_head, dev_res->res);
+			list_del(&dev_res->list);
+			kfree(dev_res);
+		}
+
+	free_list(&local_fail_head);
+	/* Release assigned resource */
+	list_for_each_entry(dev_res, head, list)
+		if (dev_res->res->parent)
+			release_resource(dev_res->res);
+	/* Restore start/end/flags from saved list */
+	list_for_each_entry(save_res, &save_head, list) {
+		struct resource *res = save_res->res;
+
+		res->start = save_res->start;
+		res->end = save_res->end;
+		res->flags = save_res->flags;
+	}
+	free_list(&save_head);
+
+requested_and_reassign:
+	/* Satisfy the must-have resource requests */
+	assign_requested_resources_sorted(head, fail_head);
+
+	/* Try to satisfy any additional optional resource requests */
+	if (realloc_head)
+		reassign_resources_sorted(realloc_head, head);
+	free_list(head);
+}
+
+static void pdev_assign_resources_sorted(struct pci_dev *dev,
+					 struct list_head *add_head,
+					 struct list_head *fail_head)
+{
+	LIST_HEAD(head);
+
+	__dev_sort_resources(dev, &head);
+	__assign_resources_sorted(&head, add_head, fail_head);
+
+}
+
+static void pbus_assign_resources_sorted(const struct pci_bus *bus,
+					 struct list_head *realloc_head,
+					 struct list_head *fail_head)
+{
+	struct pci_dev *dev;
+	LIST_HEAD(head);
+
+	list_for_each_entry(dev, &bus->devices, bus_list)
+		__dev_sort_resources(dev, &head);
+
+	__assign_resources_sorted(&head, realloc_head, fail_head);
+}
+
+void pci_setup_cardbus(struct pci_bus *bus)
+{
+	struct pci_dev *bridge = bus->self;
+	struct resource *res;
+	struct pci_bus_region region;
+
+	pci_info(bridge, "CardBus bridge to %pR\n",
+		 &bus->busn_res);
+
+	res = bus->resource[0];
+	pcibios_resource_to_bus(bridge->bus, &region, res);
+	if (res->flags & IORESOURCE_IO) {
+		/*
+		 * The IO resource is allocated a range twice as large as it
+		 * would normally need.  This allows us to set both IO regs.
+		 */
+		pci_info(bridge, "  bridge window %pR\n", res);
+		pci_write_config_dword(bridge, PCI_CB_IO_BASE_0,
+					region.start);
+		pci_write_config_dword(bridge, PCI_CB_IO_LIMIT_0,
+					region.end);
+	}
+
+	res = bus->resource[1];
+	pcibios_resource_to_bus(bridge->bus, &region, res);
+	if (res->flags & IORESOURCE_IO) {
+		pci_info(bridge, "  bridge window %pR\n", res);
+		pci_write_config_dword(bridge, PCI_CB_IO_BASE_1,
+					region.start);
+		pci_write_config_dword(bridge, PCI_CB_IO_LIMIT_1,
+					region.end);
+	}
+
+	res = bus->resource[2];
+	pcibios_resource_to_bus(bridge->bus, &region, res);
+	if (res->flags & IORESOURCE_MEM) {
+		pci_info(bridge, "  bridge window %pR\n", res);
+		pci_write_config_dword(bridge, PCI_CB_MEMORY_BASE_0,
+					region.start);
+		pci_write_config_dword(bridge, PCI_CB_MEMORY_LIMIT_0,
+					region.end);
+	}
+
+	res = bus->resource[3];
+	pcibios_resource_to_bus(bridge->bus, &region, res);
+	if (res->flags & IORESOURCE_MEM) {
+		pci_info(bridge, "  bridge window %pR\n", res);
+		pci_write_config_dword(bridge, PCI_CB_MEMORY_BASE_1,
+					region.start);
+		pci_write_config_dword(bridge, PCI_CB_MEMORY_LIMIT_1,
+					region.end);
+	}
+}
+EXPORT_SYMBOL(pci_setup_cardbus);
+
+/*
+ * Initialize bridges with base/limit values we have collected.  PCI-to-PCI
+ * Bridge Architecture Specification rev. 1.1 (1998) requires that if there
+ * are no I/O ports or memory behind the bridge, the corresponding range
+ * must be turned off by writing base value greater than limit to the
+ * bridge's base/limit registers.
+ *
+ * Note: care must be taken when updating I/O base/limit registers of
+ * bridges which support 32-bit I/O.  This update requires two config space
+ * writes, so it's quite possible that an I/O window of the bridge will
+ * have some undesirable address (e.g. 0) after the first write.  Ditto
+ * 64-bit prefetchable MMIO.
+ */
+static void pci_setup_bridge_io(struct pci_dev *bridge)
+{
+	struct resource *res;
+	struct pci_bus_region region;
+	unsigned long io_mask;
+	u8 io_base_lo, io_limit_lo;
+	u16 l;
+	u32 io_upper16;
+
+	io_mask = PCI_IO_RANGE_MASK;
+	if (bridge->io_window_1k)
+		io_mask = PCI_IO_1K_RANGE_MASK;
+
+	/* Set up the top and bottom of the PCI I/O segment for this bus */
+	res = &bridge->resource[PCI_BRIDGE_IO_WINDOW];
+	pcibios_resource_to_bus(bridge->bus, &region, res);
+	if (res->flags & IORESOURCE_IO) {
+		pci_read_config_word(bridge, PCI_IO_BASE, &l);
+		io_base_lo = (region.start >> 8) & io_mask;
+		io_limit_lo = (region.end >> 8) & io_mask;
+		l = ((u16) io_limit_lo << 8) | io_base_lo;
+		/* Set up upper 16 bits of I/O base/limit */
+		io_upper16 = (region.end & 0xffff0000) | (region.start >> 16);
+		pci_info(bridge, "  bridge window %pR\n", res);
+	} else {
+		/* Clear upper 16 bits of I/O base/limit */
+		io_upper16 = 0;
+		l = 0x00f0;
+	}
+	/* Temporarily disable the I/O range before updating PCI_IO_BASE */
+	pci_write_config_dword(bridge, PCI_IO_BASE_UPPER16, 0x0000ffff);
+	/* Update lower 16 bits of I/O base/limit */
+	pci_write_config_word(bridge, PCI_IO_BASE, l);
+	/* Update upper 16 bits of I/O base/limit */
+	pci_write_config_dword(bridge, PCI_IO_BASE_UPPER16, io_upper16);
+}
+
+static void pci_setup_bridge_mmio(struct pci_dev *bridge)
+{
+	struct resource *res;
+	struct pci_bus_region region;
+	u32 l;
+
+	/* Set up the top and bottom of the PCI Memory segment for this bus */
+	res = &bridge->resource[PCI_BRIDGE_MEM_WINDOW];
+	pcibios_resource_to_bus(bridge->bus, &region, res);
+	if (res->flags & IORESOURCE_MEM) {
+		l = (region.start >> 16) & 0xfff0;
+		l |= region.end & 0xfff00000;
+		pci_info(bridge, "  bridge window %pR\n", res);
+	} else {
+		l = 0x0000fff0;
+	}
+	pci_write_config_dword(bridge, PCI_MEMORY_BASE, l);
+}
+
+static void pci_setup_bridge_mmio_pref(struct pci_dev *bridge)
+{
+	struct resource *res;
+	struct pci_bus_region region;
+	u32 l, bu, lu;
+
+	/*
+	 * Clear out the upper 32 bits of PREF limit.  If
+	 * PCI_PREF_BASE_UPPER32 was non-zero, this temporarily disables
+	 * PREF range, which is ok.
+	 */
+	pci_write_config_dword(bridge, PCI_PREF_LIMIT_UPPER32, 0);
+
+	/* Set up PREF base/limit */
+	bu = lu = 0;
+	res = &bridge->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
+	pcibios_resource_to_bus(bridge->bus, &region, res);
+	if (res->flags & IORESOURCE_PREFETCH) {
+		l = (region.start >> 16) & 0xfff0;
+		l |= region.end & 0xfff00000;
+		if (res->flags & IORESOURCE_MEM_64) {
+			bu = upper_32_bits(region.start);
+			lu = upper_32_bits(region.end);
+		}
+		pci_info(bridge, "  bridge window %pR\n", res);
+	} else {
+		l = 0x0000fff0;
+	}
+	pci_write_config_dword(bridge, PCI_PREF_MEMORY_BASE, l);
+
+	/* Set the upper 32 bits of PREF base & limit */
+	pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, bu);
+	pci_write_config_dword(bridge, PCI_PREF_LIMIT_UPPER32, lu);
+}
+
+static void __pci_setup_bridge(struct pci_bus *bus, unsigned long type)
+{
+	struct pci_dev *bridge = bus->self;
+
+	pci_info(bridge, "PCI bridge to %pR\n",
+		 &bus->busn_res);
+
+	if (type & IORESOURCE_IO)
+		pci_setup_bridge_io(bridge);
+
+	if (type & IORESOURCE_MEM)
+		pci_setup_bridge_mmio(bridge);
+
+	if (type & IORESOURCE_PREFETCH)
+		pci_setup_bridge_mmio_pref(bridge);
+
+	pci_write_config_word(bridge, PCI_BRIDGE_CONTROL, bus->bridge_ctl);
+}
+
+void __weak pcibios_setup_bridge(struct pci_bus *bus, unsigned long type)
+{
+}
+
+void pci_setup_bridge(struct pci_bus *bus)
+{
+	unsigned long type = IORESOURCE_IO | IORESOURCE_MEM |
+				  IORESOURCE_PREFETCH;
+
+	pcibios_setup_bridge(bus, type);
+	__pci_setup_bridge(bus, type);
+}
+
+
+int pci_claim_bridge_resource(struct pci_dev *bridge, int i)
+{
+	if (i < PCI_BRIDGE_RESOURCES || i > PCI_BRIDGE_RESOURCE_END)
+		return 0;
+
+	if (pci_claim_resource(bridge, i) == 0)
+		return 0;	/* Claimed the window */
+
+	if ((bridge->class >> 8) != PCI_CLASS_BRIDGE_PCI)
+		return 0;
+
+	if (!pci_bus_clip_resource(bridge, i))
+		return -EINVAL;	/* Clipping didn't change anything */
+
+	switch (i) {
+	case PCI_BRIDGE_IO_WINDOW:
+		pci_setup_bridge_io(bridge);
+		break;
+	case PCI_BRIDGE_MEM_WINDOW:
+		pci_setup_bridge_mmio(bridge);
+		break;
+	case PCI_BRIDGE_PREF_MEM_WINDOW:
+		pci_setup_bridge_mmio_pref(bridge);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (pci_claim_resource(bridge, i) == 0)
+		return 0;	/* Claimed a smaller window */
+
+	return -EINVAL;
+}
+
+/*
+ * Check whether the bridge supports optional I/O and prefetchable memory
+ * ranges.  If not, the respective base/limit registers must be read-only
+ * and read as 0.
+ */
+static void pci_bridge_check_ranges(struct pci_bus *bus)
+{
+	struct pci_dev *bridge = bus->self;
+	struct resource *b_res;
+
+	b_res = &bridge->resource[PCI_BRIDGE_MEM_WINDOW];
+	b_res->flags |= IORESOURCE_MEM;
+
+	if (bridge->io_window) {
+		b_res = &bridge->resource[PCI_BRIDGE_IO_WINDOW];
+		b_res->flags |= IORESOURCE_IO;
+	}
+
+	if (bridge->pref_window) {
+		b_res = &bridge->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
+		b_res->flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH;
+		if (bridge->pref_64_window) {
+			b_res->flags |= IORESOURCE_MEM_64 |
+					PCI_PREF_RANGE_TYPE_64;
+		}
+	}
+}
+
+/*
+ * Helper function for sizing routines.  Assigned resources have non-NULL
+ * parent resource.
+ *
+ * Return first unassigned resource of the correct type.  If there is none,
+ * return first assigned resource of the correct type.  If none of the
+ * above, return NULL.
+ *
+ * Returning an assigned resource of the correct type allows the caller to
+ * distinguish between already assigned and no resource of the correct type.
+ */
+static struct resource *find_bus_resource_of_type(struct pci_bus *bus,
+						  unsigned long type_mask,
+						  unsigned long type)
+{
+	struct resource *r, *r_assigned = NULL;
+	int i;
+
+	pci_bus_for_each_resource(bus, r, i) {
+		if (r == &ioport_resource || r == &iomem_resource)
+			continue;
+		if (r && (r->flags & type_mask) == type && !r->parent)
+			return r;
+		if (r && (r->flags & type_mask) == type && !r_assigned)
+			r_assigned = r;
+	}
+	return r_assigned;
+}
+
+static resource_size_t calculate_iosize(resource_size_t size,
+					resource_size_t min_size,
+					resource_size_t size1,
+					resource_size_t add_size,
+					resource_size_t children_add_size,
+					resource_size_t old_size,
+					resource_size_t align)
+{
+	if (size < min_size)
+		size = min_size;
+	if (old_size == 1)
+		old_size = 0;
+	/*
+	 * To be fixed in 2.5: we should have sort of HAVE_ISA flag in the
+	 * struct pci_bus.
+	 */
+#if defined(CONFIG_ISA) || defined(CONFIG_EISA)
+	size = (size & 0xff) + ((size & ~0xffUL) << 2);
+#endif
+	size = size + size1;
+	if (size < old_size)
+		size = old_size;
+
+	size = ALIGN(max(size, add_size) + children_add_size, align);
+	return size;
+}
+
+static resource_size_t calculate_memsize(resource_size_t size,
+					 resource_size_t min_size,
+					 resource_size_t add_size,
+					 resource_size_t children_add_size,
+					 resource_size_t old_size,
+					 resource_size_t align)
+{
+	if (size < min_size)
+		size = min_size;
+	if (old_size == 1)
+		old_size = 0;
+	if (size < old_size)
+		size = old_size;
+
+	size = ALIGN(max(size, add_size) + children_add_size, align);
+	return size;
+}
+
+resource_size_t __weak pcibios_window_alignment(struct pci_bus *bus,
+						unsigned long type)
+{
+	return 1;
+}
+
+#define PCI_P2P_DEFAULT_MEM_ALIGN	0x100000	/* 1MiB */
+#define PCI_P2P_DEFAULT_IO_ALIGN	0x1000		/* 4KiB */
+#define PCI_P2P_DEFAULT_IO_ALIGN_1K	0x400		/* 1KiB */
+
+static resource_size_t window_alignment(struct pci_bus *bus, unsigned long type)
+{
+	resource_size_t align = 1, arch_align;
+
+	if (type & IORESOURCE_MEM)
+		align = PCI_P2P_DEFAULT_MEM_ALIGN;
+	else if (type & IORESOURCE_IO) {
+		/*
+		 * Per spec, I/O windows are 4K-aligned, but some bridges have
+		 * an extension to support 1K alignment.
+		 */
+		if (bus->self && bus->self->io_window_1k)
+			align = PCI_P2P_DEFAULT_IO_ALIGN_1K;
+		else
+			align = PCI_P2P_DEFAULT_IO_ALIGN;
+	}
+
+	arch_align = pcibios_window_alignment(bus, type);
+	return max(align, arch_align);
+}
+
+/**
+ * pbus_size_io() - Size the I/O window of a given bus
+ *
+ * @bus:		The bus
+ * @min_size:		The minimum I/O window that must be allocated
+ * @add_size:		Additional optional I/O window
+ * @realloc_head:	Track the additional I/O window on this list
+ *
+ * Sizing the I/O windows of the PCI-PCI bridge is trivial, since these
+ * windows have 1K or 4K granularity and the I/O ranges of non-bridge PCI
+ * devices are limited to 256 bytes.  We must be careful with the ISA
+ * aliasing though.
+ */
+static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
+			 resource_size_t add_size,
+			 struct list_head *realloc_head)
+{
+	struct pci_dev *dev;
+	struct resource *b_res = find_bus_resource_of_type(bus, IORESOURCE_IO,
+							   IORESOURCE_IO);
+	resource_size_t size = 0, size0 = 0, size1 = 0;
+	resource_size_t children_add_size = 0;
+	resource_size_t min_align, align;
+
+	if (!b_res)
+		return;
+
+	/* If resource is already assigned, nothing more to do */
+	if (b_res->parent)
+		return;
+
+	min_align = window_alignment(bus, IORESOURCE_IO);
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		int i;
+
+		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+			struct resource *r = &dev->resource[i];
+			unsigned long r_size;
+
+			if (r->parent || !(r->flags & IORESOURCE_IO))
+				continue;
+			r_size = resource_size(r);
+
+			if (r_size < 0x400)
+				/* Might be re-aligned for ISA */
+				size += r_size;
+			else
+				size1 += r_size;
+
+			align = pci_resource_alignment(dev, r);
+			if (align > min_align)
+				min_align = align;
+
+			if (realloc_head)
+				children_add_size += get_res_add_size(realloc_head, r);
+		}
+	}
+
+	size0 = calculate_iosize(size, min_size, size1, 0, 0,
+			resource_size(b_res), min_align);
+	size1 = (!realloc_head || (realloc_head && !add_size && !children_add_size)) ? size0 :
+		calculate_iosize(size, min_size, size1, add_size, children_add_size,
+			resource_size(b_res), min_align);
+	if (!size0 && !size1) {
+		if (bus->self && (b_res->start || b_res->end))
+			pci_info(bus->self, "disabling bridge window %pR to %pR (unused)\n",
+				 b_res, &bus->busn_res);
+		b_res->flags = 0;
+		return;
+	}
+
+	b_res->start = min_align;
+	b_res->end = b_res->start + size0 - 1;
+	b_res->flags |= IORESOURCE_STARTALIGN;
+	if (bus->self && size1 > size0 && realloc_head) {
+		add_to_list(realloc_head, bus->self, b_res, size1-size0,
+			    min_align);
+		pci_info(bus->self, "bridge window %pR to %pR add_size %llx\n",
+			 b_res, &bus->busn_res,
+			 (unsigned long long) size1 - size0);
+	}
+}
+
+static inline resource_size_t calculate_mem_align(resource_size_t *aligns,
+						  int max_order)
+{
+	resource_size_t align = 0;
+	resource_size_t min_align = 0;
+	int order;
+
+	for (order = 0; order <= max_order; order++) {
+		resource_size_t align1 = 1;
+
+		align1 <<= (order + 20);
+
+		if (!align)
+			min_align = align1;
+		else if (ALIGN(align + min_align, min_align) < align1)
+			min_align = align1 >> 1;
+		align += aligns[order];
+	}
+
+	return min_align;
+}
+
+/**
+ * pbus_size_mem() - Size the memory window of a given bus
+ *
+ * @bus:		The bus
+ * @mask:		Mask the resource flag, then compare it with type
+ * @type:		The type of free resource from bridge
+ * @type2:		Second match type
+ * @type3:		Third match type
+ * @min_size:		The minimum memory window that must be allocated
+ * @add_size:		Additional optional memory window
+ * @realloc_head:	Track the additional memory window on this list
+ *
+ * Calculate the size of the bus and minimal alignment which guarantees
+ * that all child resources fit in this size.
+ *
+ * Return -ENOSPC if there's no available bus resource of the desired
+ * type.  Otherwise, set the bus resource start/end to indicate the
+ * required size, add things to realloc_head (if supplied), and return 0.
+ */
+static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
+			 unsigned long type, unsigned long type2,
+			 unsigned long type3, resource_size_t min_size,
+			 resource_size_t add_size,
+			 struct list_head *realloc_head)
+{
+	struct pci_dev *dev;
+	resource_size_t min_align, align, size, size0, size1;
+	resource_size_t aligns[18]; /* Alignments from 1MB to 128GB */
+	int order, max_order;
+	struct resource *b_res = find_bus_resource_of_type(bus,
+					mask | IORESOURCE_PREFETCH, type);
+	resource_size_t children_add_size = 0;
+	resource_size_t children_add_align = 0;
+	resource_size_t add_align = 0;
+
+	if (!b_res)
+		return -ENOSPC;
+
+	/* If resource is already assigned, nothing more to do */
+	if (b_res->parent)
+		return 0;
+
+	memset(aligns, 0, sizeof(aligns));
+	max_order = 0;
+	size = 0;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		int i;
+
+		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+			struct resource *r = &dev->resource[i];
+			resource_size_t r_size;
+
+			if (r->parent || (r->flags & IORESOURCE_PCI_FIXED) ||
+			    ((r->flags & mask) != type &&
+			     (r->flags & mask) != type2 &&
+			     (r->flags & mask) != type3))
+				continue;
+			r_size = resource_size(r);
+#ifdef CONFIG_PCI_IOV
+			/* Put SRIOV requested res to the optional list */
+			if (realloc_head && i >= PCI_IOV_RESOURCES &&
+					i <= PCI_IOV_RESOURCE_END) {
+				add_align = max(pci_resource_alignment(dev, r), add_align);
+				r->end = r->start - 1;
+				add_to_list(realloc_head, dev, r, r_size, 0 /* Don't care */);
+				children_add_size += r_size;
+				continue;
+			}
+#endif
+			/*
+			 * aligns[0] is for 1MB (since bridge memory
+			 * windows are always at least 1MB aligned), so
+			 * keep "order" from being negative for smaller
+			 * resources.
+			 */
+			align = pci_resource_alignment(dev, r);
+			order = __ffs(align) - 20;
+			if (order < 0)
+				order = 0;
+			if (order >= ARRAY_SIZE(aligns)) {
+				pci_warn(dev, "disabling BAR %d: %pR (bad alignment %#llx)\n",
+					 i, r, (unsigned long long) align);
+				r->flags = 0;
+				continue;
+			}
+			size += max(r_size, align);
+			/*
+			 * Exclude ranges with size > align from calculation of
+			 * the alignment.
+			 */
+			if (r_size <= align)
+				aligns[order] += align;
+			if (order > max_order)
+				max_order = order;
+
+			if (realloc_head) {
+				children_add_size += get_res_add_size(realloc_head, r);
+				children_add_align = get_res_add_align(realloc_head, r);
+				add_align = max(add_align, children_add_align);
+			}
+		}
+	}
+
+	min_align = calculate_mem_align(aligns, max_order);
+	min_align = max(min_align, window_alignment(bus, b_res->flags));
+	size0 = calculate_memsize(size, min_size, 0, 0, resource_size(b_res), min_align);
+	add_align = max(min_align, add_align);
+	size1 = (!realloc_head || (realloc_head && !add_size && !children_add_size)) ? size0 :
+		calculate_memsize(size, min_size, add_size, children_add_size,
+				resource_size(b_res), add_align);
+	if (!size0 && !size1) {
+		if (bus->self && (b_res->start || b_res->end))
+			pci_info(bus->self, "disabling bridge window %pR to %pR (unused)\n",
+				 b_res, &bus->busn_res);
+		b_res->flags = 0;
+		return 0;
+	}
+	b_res->start = min_align;
+	b_res->end = size0 + min_align - 1;
+	b_res->flags |= IORESOURCE_STARTALIGN;
+	if (bus->self && size1 > size0 && realloc_head) {
+		add_to_list(realloc_head, bus->self, b_res, size1-size0, add_align);
+		pci_info(bus->self, "bridge window %pR to %pR add_size %llx add_align %llx\n",
+			   b_res, &bus->busn_res,
+			   (unsigned long long) (size1 - size0),
+			   (unsigned long long) add_align);
+	}
+	return 0;
+}
+
+unsigned long pci_cardbus_resource_alignment(struct resource *res)
+{
+	if (res->flags & IORESOURCE_IO)
+		return pci_cardbus_io_size;
+	if (res->flags & IORESOURCE_MEM)
+		return pci_cardbus_mem_size;
+	return 0;
+}
+
+static void pci_bus_size_cardbus(struct pci_bus *bus,
+				 struct list_head *realloc_head)
+{
+	struct pci_dev *bridge = bus->self;
+	struct resource *b_res;
+	resource_size_t b_res_3_size = pci_cardbus_mem_size * 2;
+	u16 ctrl;
+
+	b_res = &bridge->resource[PCI_CB_BRIDGE_IO_0_WINDOW];
+	if (b_res->parent)
+		goto handle_b_res_1;
+	/*
+	 * Reserve some resources for CardBus.  We reserve a fixed amount
+	 * of bus space for CardBus bridges.
+	 */
+	b_res->start = pci_cardbus_io_size;
+	b_res->end = b_res->start + pci_cardbus_io_size - 1;
+	b_res->flags |= IORESOURCE_IO | IORESOURCE_STARTALIGN;
+	if (realloc_head) {
+		b_res->end -= pci_cardbus_io_size;
+		add_to_list(realloc_head, bridge, b_res, pci_cardbus_io_size,
+			    pci_cardbus_io_size);
+	}
+
+handle_b_res_1:
+	b_res = &bridge->resource[PCI_CB_BRIDGE_IO_1_WINDOW];
+	if (b_res->parent)
+		goto handle_b_res_2;
+	b_res->start = pci_cardbus_io_size;
+	b_res->end = b_res->start + pci_cardbus_io_size - 1;
+	b_res->flags |= IORESOURCE_IO | IORESOURCE_STARTALIGN;
+	if (realloc_head) {
+		b_res->end -= pci_cardbus_io_size;
+		add_to_list(realloc_head, bridge, b_res, pci_cardbus_io_size,
+			    pci_cardbus_io_size);
+	}
+
+handle_b_res_2:
+	/* MEM1 must not be pref MMIO */
+	pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
+	if (ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM1) {
+		ctrl &= ~PCI_CB_BRIDGE_CTL_PREFETCH_MEM1;
+		pci_write_config_word(bridge, PCI_CB_BRIDGE_CONTROL, ctrl);
+		pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
+	}
+
+	/* Check whether prefetchable memory is supported by this bridge. */
+	pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
+	if (!(ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM0)) {
+		ctrl |= PCI_CB_BRIDGE_CTL_PREFETCH_MEM0;
+		pci_write_config_word(bridge, PCI_CB_BRIDGE_CONTROL, ctrl);
+		pci_read_config_word(bridge, PCI_CB_BRIDGE_CONTROL, &ctrl);
+	}
+
+	b_res = &bridge->resource[PCI_CB_BRIDGE_MEM_0_WINDOW];
+	if (b_res->parent)
+		goto handle_b_res_3;
+	/*
+	 * If we have prefetchable memory support, allocate two regions.
+	 * Otherwise, allocate one region of twice the size.
+	 */
+	if (ctrl & PCI_CB_BRIDGE_CTL_PREFETCH_MEM0) {
+		b_res->start = pci_cardbus_mem_size;
+		b_res->end = b_res->start + pci_cardbus_mem_size - 1;
+		b_res->flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH |
+				    IORESOURCE_STARTALIGN;
+		if (realloc_head) {
+			b_res->end -= pci_cardbus_mem_size;
+			add_to_list(realloc_head, bridge, b_res,
+				    pci_cardbus_mem_size, pci_cardbus_mem_size);
+		}
+
+		/* Reduce that to half */
+		b_res_3_size = pci_cardbus_mem_size;
+	}
+
+handle_b_res_3:
+	b_res = &bridge->resource[PCI_CB_BRIDGE_MEM_1_WINDOW];
+	if (b_res->parent)
+		goto handle_done;
+	b_res->start = pci_cardbus_mem_size;
+	b_res->end = b_res->start + b_res_3_size - 1;
+	b_res->flags |= IORESOURCE_MEM | IORESOURCE_STARTALIGN;
+	if (realloc_head) {
+		b_res->end -= b_res_3_size;
+		add_to_list(realloc_head, bridge, b_res, b_res_3_size,
+			    pci_cardbus_mem_size);
+	}
+
+handle_done:
+	;
+}
+
+void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
+{
+	struct pci_dev *dev;
+	unsigned long mask, prefmask, type2 = 0, type3 = 0;
+	resource_size_t additional_io_size = 0, additional_mmio_size = 0,
+			additional_mmio_pref_size = 0;
+	struct resource *pref;
+	struct pci_host_bridge *host;
+	int hdr_type, i, ret;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		struct pci_bus *b = dev->subordinate;
+		if (!b)
+			continue;
+
+		switch (dev->hdr_type) {
+		case PCI_HEADER_TYPE_CARDBUS:
+			pci_bus_size_cardbus(b, realloc_head);
+			break;
+
+		case PCI_HEADER_TYPE_BRIDGE:
+		default:
+			__pci_bus_size_bridges(b, realloc_head);
+			break;
+		}
+	}
+
+	/* The root bus? */
+	if (pci_is_root_bus(bus)) {
+		host = to_pci_host_bridge(bus->bridge);
+		if (!host->size_windows)
+			return;
+		pci_bus_for_each_resource(bus, pref, i)
+			if (pref && (pref->flags & IORESOURCE_PREFETCH))
+				break;
+		hdr_type = -1;	/* Intentionally invalid - not a PCI device. */
+	} else {
+		pref = &bus->self->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
+		hdr_type = bus->self->hdr_type;
+	}
+
+	switch (hdr_type) {
+	case PCI_HEADER_TYPE_CARDBUS:
+		/* Don't size CardBuses yet */
+		break;
+
+	case PCI_HEADER_TYPE_BRIDGE:
+		pci_bridge_check_ranges(bus);
+		if (bus->self->is_hotplug_bridge) {
+			additional_io_size  = pci_hotplug_io_size;
+			additional_mmio_size = pci_hotplug_mmio_size;
+			additional_mmio_pref_size = pci_hotplug_mmio_pref_size;
+		}
+		fallthrough;
+	default:
+		pbus_size_io(bus, realloc_head ? 0 : additional_io_size,
+			     additional_io_size, realloc_head);
+
+		/*
+		 * If there's a 64-bit prefetchable MMIO window, compute
+		 * the size required to put all 64-bit prefetchable
+		 * resources in it.
+		 */
+		mask = IORESOURCE_MEM;
+		prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH;
+		if (pref && (pref->flags & IORESOURCE_MEM_64)) {
+			prefmask |= IORESOURCE_MEM_64;
+			ret = pbus_size_mem(bus, prefmask, prefmask,
+				prefmask, prefmask,
+				realloc_head ? 0 : additional_mmio_pref_size,
+				additional_mmio_pref_size, realloc_head);
+
+			/*
+			 * If successful, all non-prefetchable resources
+			 * and any 32-bit prefetchable resources will go in
+			 * the non-prefetchable window.
+			 */
+			if (ret == 0) {
+				mask = prefmask;
+				type2 = prefmask & ~IORESOURCE_MEM_64;
+				type3 = prefmask & ~IORESOURCE_PREFETCH;
+			}
+		}
+
+		/*
+		 * If there is no 64-bit prefetchable window, compute the
+		 * size required to put all prefetchable resources in the
+		 * 32-bit prefetchable window (if there is one).
+		 */
+		if (!type2) {
+			prefmask &= ~IORESOURCE_MEM_64;
+			ret = pbus_size_mem(bus, prefmask, prefmask,
+				prefmask, prefmask,
+				realloc_head ? 0 : additional_mmio_pref_size,
+				additional_mmio_pref_size, realloc_head);
+
+			/*
+			 * If successful, only non-prefetchable resources
+			 * will go in the non-prefetchable window.
+			 */
+			if (ret == 0)
+				mask = prefmask;
+			else
+				additional_mmio_size += additional_mmio_pref_size;
+
+			type2 = type3 = IORESOURCE_MEM;
+		}
+
+		/*
+		 * Compute the size required to put everything else in the
+		 * non-prefetchable window. This includes:
+		 *
+		 *   - all non-prefetchable resources
+		 *   - 32-bit prefetchable resources if there's a 64-bit
+		 *     prefetchable window or no prefetchable window at all
+		 *   - 64-bit prefetchable resources if there's no prefetchable
+		 *     window at all
+		 *
+		 * Note that the strategy in __pci_assign_resource() must match
+		 * that used here. Specifically, we cannot put a 32-bit
+		 * prefetchable resource in a 64-bit prefetchable window.
+		 */
+		pbus_size_mem(bus, mask, IORESOURCE_MEM, type2, type3,
+			      realloc_head ? 0 : additional_mmio_size,
+			      additional_mmio_size, realloc_head);
+		break;
+	}
+}
+
+void pci_bus_size_bridges(struct pci_bus *bus)
+{
+	__pci_bus_size_bridges(bus, NULL);
+}
+EXPORT_SYMBOL(pci_bus_size_bridges);
+
+static void assign_fixed_resource_on_bus(struct pci_bus *b, struct resource *r)
+{
+	int i;
+	struct resource *parent_r;
+	unsigned long mask = IORESOURCE_IO | IORESOURCE_MEM |
+			     IORESOURCE_PREFETCH;
+
+	pci_bus_for_each_resource(b, parent_r, i) {
+		if (!parent_r)
+			continue;
+
+		if ((r->flags & mask) == (parent_r->flags & mask) &&
+		    resource_contains(parent_r, r))
+			request_resource(parent_r, r);
+	}
+}
+
+/*
+ * Try to assign any resources marked as IORESOURCE_PCI_FIXED, as they are
+ * skipped by pbus_assign_resources_sorted().
+ */
+static void pdev_assign_fixed_resources(struct pci_dev *dev)
+{
+	int i;
+
+	for (i = 0; i <  PCI_NUM_RESOURCES; i++) {
+		struct pci_bus *b;
+		struct resource *r = &dev->resource[i];
+
+		if (r->parent || !(r->flags & IORESOURCE_PCI_FIXED) ||
+		    !(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
+			continue;
+
+		b = dev->bus;
+		while (b && !r->parent) {
+			assign_fixed_resource_on_bus(b, r);
+			b = b->parent;
+		}
+	}
+}
+
+void __pci_bus_assign_resources(const struct pci_bus *bus,
+				struct list_head *realloc_head,
+				struct list_head *fail_head)
+{
+	struct pci_bus *b;
+	struct pci_dev *dev;
+
+	pbus_assign_resources_sorted(bus, realloc_head, fail_head);
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		pdev_assign_fixed_resources(dev);
+
+		b = dev->subordinate;
+		if (!b)
+			continue;
+
+		__pci_bus_assign_resources(b, realloc_head, fail_head);
+
+		switch (dev->hdr_type) {
+		case PCI_HEADER_TYPE_BRIDGE:
+			if (!pci_is_enabled(dev))
+				pci_setup_bridge(b);
+			break;
+
+		case PCI_HEADER_TYPE_CARDBUS:
+			pci_setup_cardbus(b);
+			break;
+
+		default:
+			pci_info(dev, "not setting up bridge for bus %04x:%02x\n",
+				 pci_domain_nr(b), b->number);
+			break;
+		}
+	}
+}
+
+void pci_bus_assign_resources(const struct pci_bus *bus)
+{
+	__pci_bus_assign_resources(bus, NULL, NULL);
+}
+EXPORT_SYMBOL(pci_bus_assign_resources);
+
+static void pci_claim_device_resources(struct pci_dev *dev)
+{
+	int i;
+
+	for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) {
+		struct resource *r = &dev->resource[i];
+
+		if (!r->flags || r->parent)
+			continue;
+
+		pci_claim_resource(dev, i);
+	}
+}
+
+static void pci_claim_bridge_resources(struct pci_dev *dev)
+{
+	int i;
+
+	for (i = PCI_BRIDGE_RESOURCES; i < PCI_NUM_RESOURCES; i++) {
+		struct resource *r = &dev->resource[i];
+
+		if (!r->flags || r->parent)
+			continue;
+
+		pci_claim_bridge_resource(dev, i);
+	}
+}
+
+static void pci_bus_allocate_dev_resources(struct pci_bus *b)
+{
+	struct pci_dev *dev;
+	struct pci_bus *child;
+
+	list_for_each_entry(dev, &b->devices, bus_list) {
+		pci_claim_device_resources(dev);
+
+		child = dev->subordinate;
+		if (child)
+			pci_bus_allocate_dev_resources(child);
+	}
+}
+
+static void pci_bus_allocate_resources(struct pci_bus *b)
+{
+	struct pci_bus *child;
+
+	/*
+	 * Carry out a depth-first search on the PCI bus tree to allocate
+	 * bridge apertures.  Read the programmed bridge bases and
+	 * recursively claim the respective bridge resources.
+	 */
+	if (b->self) {
+		pci_read_bridge_bases(b);
+		pci_claim_bridge_resources(b->self);
+	}
+
+	list_for_each_entry(child, &b->children, node)
+		pci_bus_allocate_resources(child);
+}
+
+void pci_bus_claim_resources(struct pci_bus *b)
+{
+	pci_bus_allocate_resources(b);
+	pci_bus_allocate_dev_resources(b);
+}
+EXPORT_SYMBOL(pci_bus_claim_resources);
+
+static void __pci_bridge_assign_resources(const struct pci_dev *bridge,
+					  struct list_head *add_head,
+					  struct list_head *fail_head)
+{
+	struct pci_bus *b;
+
+	pdev_assign_resources_sorted((struct pci_dev *)bridge,
+					 add_head, fail_head);
+
+	b = bridge->subordinate;
+	if (!b)
+		return;
+
+	__pci_bus_assign_resources(b, add_head, fail_head);
+
+	switch (bridge->class >> 8) {
+	case PCI_CLASS_BRIDGE_PCI:
+		pci_setup_bridge(b);
+		break;
+
+	case PCI_CLASS_BRIDGE_CARDBUS:
+		pci_setup_cardbus(b);
+		break;
+
+	default:
+		pci_info(bridge, "not setting up bridge for bus %04x:%02x\n",
+			 pci_domain_nr(b), b->number);
+		break;
+	}
+}
+
+#define PCI_RES_TYPE_MASK \
+	(IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH |\
+	 IORESOURCE_MEM_64)
+
+static void pci_bridge_release_resources(struct pci_bus *bus,
+					 unsigned long type)
+{
+	struct pci_dev *dev = bus->self;
+	struct resource *r;
+	unsigned old_flags = 0;
+	struct resource *b_res;
+	int idx = 1;
+
+	b_res = &dev->resource[PCI_BRIDGE_RESOURCES];
+
+	/*
+	 * 1. If IO port assignment fails, release bridge IO port.
+	 * 2. If non pref MMIO assignment fails, release bridge nonpref MMIO.
+	 * 3. If 64bit pref MMIO assignment fails, and bridge pref is 64bit,
+	 *    release bridge pref MMIO.
+	 * 4. If pref MMIO assignment fails, and bridge pref is 32bit,
+	 *    release bridge pref MMIO.
+	 * 5. If pref MMIO assignment fails, and bridge pref is not
+	 *    assigned, release bridge nonpref MMIO.
+	 */
+	if (type & IORESOURCE_IO)
+		idx = 0;
+	else if (!(type & IORESOURCE_PREFETCH))
+		idx = 1;
+	else if ((type & IORESOURCE_MEM_64) &&
+		 (b_res[2].flags & IORESOURCE_MEM_64))
+		idx = 2;
+	else if (!(b_res[2].flags & IORESOURCE_MEM_64) &&
+		 (b_res[2].flags & IORESOURCE_PREFETCH))
+		idx = 2;
+	else
+		idx = 1;
+
+	r = &b_res[idx];
+
+	if (!r->parent)
+		return;
+
+	/* If there are children, release them all */
+	release_child_resources(r);
+	if (!release_resource(r)) {
+		type = old_flags = r->flags & PCI_RES_TYPE_MASK;
+		pci_info(dev, "resource %d %pR released\n",
+			 PCI_BRIDGE_RESOURCES + idx, r);
+		/* Keep the old size */
+		r->end = resource_size(r) - 1;
+		r->start = 0;
+		r->flags = 0;
+
+		/* Avoiding touch the one without PREF */
+		if (type & IORESOURCE_PREFETCH)
+			type = IORESOURCE_PREFETCH;
+		__pci_setup_bridge(bus, type);
+		/* For next child res under same bridge */
+		r->flags = old_flags;
+	}
+}
+
+enum release_type {
+	leaf_only,
+	whole_subtree,
+};
+
+/*
+ * Try to release PCI bridge resources from leaf bridge, so we can allocate
+ * a larger window later.
+ */
+static void pci_bus_release_bridge_resources(struct pci_bus *bus,
+					     unsigned long type,
+					     enum release_type rel_type)
+{
+	struct pci_dev *dev;
+	bool is_leaf_bridge = true;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		struct pci_bus *b = dev->subordinate;
+		if (!b)
+			continue;
+
+		is_leaf_bridge = false;
+
+		if ((dev->class >> 8) != PCI_CLASS_BRIDGE_PCI)
+			continue;
+
+		if (rel_type == whole_subtree)
+			pci_bus_release_bridge_resources(b, type,
+						 whole_subtree);
+	}
+
+	if (pci_is_root_bus(bus))
+		return;
+
+	if ((bus->self->class >> 8) != PCI_CLASS_BRIDGE_PCI)
+		return;
+
+	if ((rel_type == whole_subtree) || is_leaf_bridge)
+		pci_bridge_release_resources(bus, type);
+}
+
+static void pci_bus_dump_res(struct pci_bus *bus)
+{
+	struct resource *res;
+	int i;
+
+	pci_bus_for_each_resource(bus, res, i) {
+		if (!res || !res->end || !res->flags)
+			continue;
+
+		dev_info(&bus->dev, "resource %d %pR\n", i, res);
+	}
+}
+
+static void pci_bus_dump_resources(struct pci_bus *bus)
+{
+	struct pci_bus *b;
+	struct pci_dev *dev;
+
+
+	pci_bus_dump_res(bus);
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		b = dev->subordinate;
+		if (!b)
+			continue;
+
+		pci_bus_dump_resources(b);
+	}
+}
+
+static int pci_bus_get_depth(struct pci_bus *bus)
+{
+	int depth = 0;
+	struct pci_bus *child_bus;
+
+	list_for_each_entry(child_bus, &bus->children, node) {
+		int ret;
+
+		ret = pci_bus_get_depth(child_bus);
+		if (ret + 1 > depth)
+			depth = ret + 1;
+	}
+
+	return depth;
+}
+
+/*
+ * -1: undefined, will auto detect later
+ *  0: disabled by user
+ *  1: disabled by auto detect
+ *  2: enabled by user
+ *  3: enabled by auto detect
+ */
+enum enable_type {
+	undefined = -1,
+	user_disabled,
+	auto_disabled,
+	user_enabled,
+	auto_enabled,
+};
+
+static enum enable_type pci_realloc_enable = undefined;
+void __init pci_realloc_get_opt(char *str)
+{
+	if (!strncmp(str, "off", 3))
+		pci_realloc_enable = user_disabled;
+	else if (!strncmp(str, "on", 2))
+		pci_realloc_enable = user_enabled;
+}
+static bool pci_realloc_enabled(enum enable_type enable)
+{
+	return enable >= user_enabled;
+}
+
+#if defined(CONFIG_PCI_IOV) && defined(CONFIG_PCI_REALLOC_ENABLE_AUTO)
+static int iov_resources_unassigned(struct pci_dev *dev, void *data)
+{
+	int i;
+	bool *unassigned = data;
+
+	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
+		struct resource *r = &dev->resource[i + PCI_IOV_RESOURCES];
+		struct pci_bus_region region;
+
+		/* Not assigned or rejected by kernel? */
+		if (!r->flags)
+			continue;
+
+		pcibios_resource_to_bus(dev->bus, &region, r);
+		if (!region.start) {
+			*unassigned = true;
+			return 1; /* Return early from pci_walk_bus() */
+		}
+	}
+
+	return 0;
+}
+
+static enum enable_type pci_realloc_detect(struct pci_bus *bus,
+					   enum enable_type enable_local)
+{
+	bool unassigned = false;
+	struct pci_host_bridge *host;
+
+	if (enable_local != undefined)
+		return enable_local;
+
+	host = pci_find_host_bridge(bus);
+	if (host->preserve_config)
+		return auto_disabled;
+
+	pci_walk_bus(bus, iov_resources_unassigned, &unassigned);
+	if (unassigned)
+		return auto_enabled;
+
+	return enable_local;
+}
+#else
+static enum enable_type pci_realloc_detect(struct pci_bus *bus,
+					   enum enable_type enable_local)
+{
+	return enable_local;
+}
+#endif
+
+/*
+ * First try will not touch PCI bridge res.
+ * Second and later try will clear small leaf bridge res.
+ * Will stop till to the max depth if can not find good one.
+ */
+void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
+{
+	LIST_HEAD(realloc_head);
+	/* List of resources that want additional resources */
+	struct list_head *add_list = NULL;
+	int tried_times = 0;
+	enum release_type rel_type = leaf_only;
+	LIST_HEAD(fail_head);
+	struct pci_dev_resource *fail_res;
+	int pci_try_num = 1;
+	enum enable_type enable_local;
+
+	/* Don't realloc if asked to do so */
+	enable_local = pci_realloc_detect(bus, pci_realloc_enable);
+	if (pci_realloc_enabled(enable_local)) {
+		int max_depth = pci_bus_get_depth(bus);
+
+		pci_try_num = max_depth + 1;
+		dev_info(&bus->dev, "max bus depth: %d pci_try_num: %d\n",
+			 max_depth, pci_try_num);
+	}
+
+again:
+	/*
+	 * Last try will use add_list, otherwise will try good to have as must
+	 * have, so can realloc parent bridge resource
+	 */
+	if (tried_times + 1 == pci_try_num)
+		add_list = &realloc_head;
+	/*
+	 * Depth first, calculate sizes and alignments of all subordinate buses.
+	 */
+	__pci_bus_size_bridges(bus, add_list);
+
+	/* Depth last, allocate resources and update the hardware. */
+	__pci_bus_assign_resources(bus, add_list, &fail_head);
+	if (add_list)
+		BUG_ON(!list_empty(add_list));
+	tried_times++;
+
+	/* Any device complain? */
+	if (list_empty(&fail_head))
+		goto dump;
+
+	if (tried_times >= pci_try_num) {
+		if (enable_local == undefined)
+			dev_info(&bus->dev, "Some PCI device resources are unassigned, try booting with pci=realloc\n");
+		else if (enable_local == auto_enabled)
+			dev_info(&bus->dev, "Automatically enabled pci realloc, if you have problem, try booting with pci=realloc=off\n");
+
+		free_list(&fail_head);
+		goto dump;
+	}
+
+	dev_info(&bus->dev, "No. %d try to assign unassigned res\n",
+		 tried_times + 1);
+
+	/* Third times and later will not check if it is leaf */
+	if ((tried_times + 1) > 2)
+		rel_type = whole_subtree;
+
+	/*
+	 * Try to release leaf bridge's resources that doesn't fit resource of
+	 * child device under that bridge.
+	 */
+	list_for_each_entry(fail_res, &fail_head, list)
+		pci_bus_release_bridge_resources(fail_res->dev->bus,
+						 fail_res->flags & PCI_RES_TYPE_MASK,
+						 rel_type);
+
+	/* Restore size and flags */
+	list_for_each_entry(fail_res, &fail_head, list) {
+		struct resource *res = fail_res->res;
+		int idx;
+
+		res->start = fail_res->start;
+		res->end = fail_res->end;
+		res->flags = fail_res->flags;
+
+		if (pci_is_bridge(fail_res->dev)) {
+			idx = res - &fail_res->dev->resource[0];
+			if (idx >= PCI_BRIDGE_RESOURCES &&
+			    idx <= PCI_BRIDGE_RESOURCE_END)
+				res->flags = 0;
+		}
+	}
+	free_list(&fail_head);
+
+	goto again;
+
+dump:
+	/* Dump the resource on buses */
+	pci_bus_dump_resources(bus);
+}
+
+void __init pci_assign_unassigned_resources(void)
+{
+	struct pci_bus *root_bus;
+
+	list_for_each_entry(root_bus, &pci_root_buses, node) {
+		pci_assign_unassigned_root_bus_resources(root_bus);
+
+		/* Make sure the root bridge has a companion ACPI device */
+		if (ACPI_HANDLE(root_bus->bridge))
+			acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
+	}
+}
+
+static void adjust_bridge_window(struct pci_dev *bridge, struct resource *res,
+				 struct list_head *add_list,
+				 resource_size_t new_size)
+{
+	resource_size_t add_size, size = resource_size(res);
+
+	if (res->parent)
+		return;
+
+	if (!new_size)
+		return;
+
+	if (new_size > size) {
+		add_size = new_size - size;
+		pci_dbg(bridge, "bridge window %pR extended by %pa\n", res,
+			&add_size);
+	} else if (new_size < size) {
+		add_size = size - new_size;
+		pci_dbg(bridge, "bridge window %pR shrunken by %pa\n", res,
+			&add_size);
+	} else {
+		return;
+	}
+
+	res->end = res->start + new_size - 1;
+	remove_from_list(add_list, res);
+}
+
+static void remove_dev_resource(struct resource *avail, struct pci_dev *dev,
+				struct resource *res)
+{
+	resource_size_t size, align, tmp;
+
+	size = resource_size(res);
+	if (!size)
+		return;
+
+	align = pci_resource_alignment(dev, res);
+	align = align ? ALIGN(avail->start, align) - avail->start : 0;
+	tmp = align + size;
+	avail->start = min(avail->start + tmp, avail->end + 1);
+}
+
+static void remove_dev_resources(struct pci_dev *dev, struct resource *io,
+				 struct resource *mmio,
+				 struct resource *mmio_pref)
+{
+	int i;
+
+	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+		struct resource *res = &dev->resource[i];
+
+		if (resource_type(res) == IORESOURCE_IO) {
+			remove_dev_resource(io, dev, res);
+		} else if (resource_type(res) == IORESOURCE_MEM) {
+
+			/*
+			 * Make sure prefetchable memory is reduced from
+			 * the correct resource. Specifically we put 32-bit
+			 * prefetchable memory in non-prefetchable window
+			 * if there is an 64-bit pretchable window.
+			 *
+			 * See comments in __pci_bus_size_bridges() for
+			 * more information.
+			 */
+			if ((res->flags & IORESOURCE_PREFETCH) &&
+			    ((res->flags & IORESOURCE_MEM_64) ==
+			     (mmio_pref->flags & IORESOURCE_MEM_64)))
+				remove_dev_resource(mmio_pref, dev, res);
+			else
+				remove_dev_resource(mmio, dev, res);
+		}
+	}
+}
+
+/*
+ * io, mmio and mmio_pref contain the total amount of bridge window space
+ * available. This includes the minimal space needed to cover all the
+ * existing devices on the bus and the possible extra space that can be
+ * shared with the bridges.
+ */
+static void pci_bus_distribute_available_resources(struct pci_bus *bus,
+					    struct list_head *add_list,
+					    struct resource io,
+					    struct resource mmio,
+					    struct resource mmio_pref)
+{
+	unsigned int normal_bridges = 0, hotplug_bridges = 0;
+	struct resource *io_res, *mmio_res, *mmio_pref_res;
+	struct pci_dev *dev, *bridge = bus->self;
+	resource_size_t io_per_b, mmio_per_b, mmio_pref_per_b, align;
+
+	io_res = &bridge->resource[PCI_BRIDGE_IO_WINDOW];
+	mmio_res = &bridge->resource[PCI_BRIDGE_MEM_WINDOW];
+	mmio_pref_res = &bridge->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
+
+	/*
+	 * The alignment of this bridge is yet to be considered, hence it must
+	 * be done now before extending its bridge window.
+	 */
+	align = pci_resource_alignment(bridge, io_res);
+	if (!io_res->parent && align)
+		io.start = min(ALIGN(io.start, align), io.end + 1);
+
+	align = pci_resource_alignment(bridge, mmio_res);
+	if (!mmio_res->parent && align)
+		mmio.start = min(ALIGN(mmio.start, align), mmio.end + 1);
+
+	align = pci_resource_alignment(bridge, mmio_pref_res);
+	if (!mmio_pref_res->parent && align)
+		mmio_pref.start = min(ALIGN(mmio_pref.start, align),
+			mmio_pref.end + 1);
+
+	/*
+	 * Now that we have adjusted for alignment, update the bridge window
+	 * resources to fill as much remaining resource space as possible.
+	 */
+	adjust_bridge_window(bridge, io_res, add_list, resource_size(&io));
+	adjust_bridge_window(bridge, mmio_res, add_list, resource_size(&mmio));
+	adjust_bridge_window(bridge, mmio_pref_res, add_list,
+			     resource_size(&mmio_pref));
+
+	/*
+	 * Calculate how many hotplug bridges and normal bridges there
+	 * are on this bus.  We will distribute the additional available
+	 * resources between hotplug bridges.
+	 */
+	for_each_pci_bridge(dev, bus) {
+		if (dev->is_hotplug_bridge)
+			hotplug_bridges++;
+		else
+			normal_bridges++;
+	}
+
+	if (!(hotplug_bridges + normal_bridges))
+		return;
+
+	/*
+	 * Calculate the amount of space we can forward from "bus" to any
+	 * downstream buses, i.e., the space left over after assigning the
+	 * BARs and windows on "bus".
+	 */
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		if (!dev->is_virtfn)
+			remove_dev_resources(dev, &io, &mmio, &mmio_pref);
+	}
+
+	/*
+	 * If there is at least one hotplug bridge on this bus it gets all
+	 * the extra resource space that was left after the reductions
+	 * above.
+	 *
+	 * If there are no hotplug bridges the extra resource space is
+	 * split between non-hotplug bridges. This is to allow possible
+	 * hotplug bridges below them to get the extra space as well.
+	 */
+	if (hotplug_bridges) {
+		io_per_b = div64_ul(resource_size(&io), hotplug_bridges);
+		mmio_per_b = div64_ul(resource_size(&mmio), hotplug_bridges);
+		mmio_pref_per_b = div64_ul(resource_size(&mmio_pref),
+					   hotplug_bridges);
+	} else {
+		io_per_b = div64_ul(resource_size(&io), normal_bridges);
+		mmio_per_b = div64_ul(resource_size(&mmio), normal_bridges);
+		mmio_pref_per_b = div64_ul(resource_size(&mmio_pref),
+					   normal_bridges);
+	}
+
+	for_each_pci_bridge(dev, bus) {
+		struct resource *res;
+		struct pci_bus *b;
+
+		b = dev->subordinate;
+		if (!b)
+			continue;
+		if (hotplug_bridges && !dev->is_hotplug_bridge)
+			continue;
+
+		res = &dev->resource[PCI_BRIDGE_IO_WINDOW];
+
+		/*
+		 * Make sure the split resource space is properly aligned
+		 * for bridge windows (align it down to avoid going above
+		 * what is available).
+		 */
+		align = pci_resource_alignment(dev, res);
+		io.end = align ? io.start + ALIGN_DOWN(io_per_b, align) - 1
+			       : io.start + io_per_b - 1;
+
+		/*
+		 * The x_per_b holds the extra resource space that can be
+		 * added for each bridge but there is the minimal already
+		 * reserved as well so adjust x.start down accordingly to
+		 * cover the whole space.
+		 */
+		io.start -= resource_size(res);
+
+		res = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
+		align = pci_resource_alignment(dev, res);
+		mmio.end = align ? mmio.start + ALIGN_DOWN(mmio_per_b, align) - 1
+				 : mmio.start + mmio_per_b - 1;
+		mmio.start -= resource_size(res);
+
+		res = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
+		align = pci_resource_alignment(dev, res);
+		mmio_pref.end = align ? mmio_pref.start +
+					ALIGN_DOWN(mmio_pref_per_b, align) - 1
+				      : mmio_pref.start + mmio_pref_per_b - 1;
+		mmio_pref.start -= resource_size(res);
+
+		pci_bus_distribute_available_resources(b, add_list, io, mmio,
+						       mmio_pref);
+
+		io.start += io.end + 1;
+		mmio.start += mmio.end + 1;
+		mmio_pref.start += mmio_pref.end + 1;
+	}
+}
+
+static void pci_bridge_distribute_available_resources(struct pci_dev *bridge,
+						     struct list_head *add_list)
+{
+	struct resource available_io, available_mmio, available_mmio_pref;
+
+	if (!bridge->is_hotplug_bridge)
+		return;
+
+	/* Take the initial extra resources from the hotplug port */
+	available_io = bridge->resource[PCI_BRIDGE_IO_WINDOW];
+	available_mmio = bridge->resource[PCI_BRIDGE_MEM_WINDOW];
+	available_mmio_pref = bridge->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
+
+	pci_bus_distribute_available_resources(bridge->subordinate,
+					       add_list, available_io,
+					       available_mmio,
+					       available_mmio_pref);
+}
+
+void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
+{
+	struct pci_bus *parent = bridge->subordinate;
+	/* List of resources that want additional resources */
+	LIST_HEAD(add_list);
+
+	int tried_times = 0;
+	LIST_HEAD(fail_head);
+	struct pci_dev_resource *fail_res;
+	int retval;
+
+again:
+	__pci_bus_size_bridges(parent, &add_list);
+
+	/*
+	 * Distribute remaining resources (if any) equally between hotplug
+	 * bridges below.  This makes it possible to extend the hierarchy
+	 * later without running out of resources.
+	 */
+	pci_bridge_distribute_available_resources(bridge, &add_list);
+
+	__pci_bridge_assign_resources(bridge, &add_list, &fail_head);
+	BUG_ON(!list_empty(&add_list));
+	tried_times++;
+
+	if (list_empty(&fail_head))
+		goto enable_all;
+
+	if (tried_times >= 2) {
+		/* Still fail, don't need to try more */
+		free_list(&fail_head);
+		goto enable_all;
+	}
+
+	printk(KERN_DEBUG "PCI: No. %d try to assign unassigned res\n",
+			 tried_times + 1);
+
+	/*
+	 * Try to release leaf bridge's resources that aren't big enough
+	 * to contain child device resources.
+	 */
+	list_for_each_entry(fail_res, &fail_head, list)
+		pci_bus_release_bridge_resources(fail_res->dev->bus,
+						 fail_res->flags & PCI_RES_TYPE_MASK,
+						 whole_subtree);
+
+	/* Restore size and flags */
+	list_for_each_entry(fail_res, &fail_head, list) {
+		struct resource *res = fail_res->res;
+		int idx;
+
+		res->start = fail_res->start;
+		res->end = fail_res->end;
+		res->flags = fail_res->flags;
+
+		if (pci_is_bridge(fail_res->dev)) {
+			idx = res - &fail_res->dev->resource[0];
+			if (idx >= PCI_BRIDGE_RESOURCES &&
+			    idx <= PCI_BRIDGE_RESOURCE_END)
+				res->flags = 0;
+		}
+	}
+	free_list(&fail_head);
+
+	goto again;
+
+enable_all:
+	retval = pci_reenable_device(bridge);
+	if (retval)
+		pci_err(bridge, "Error reenabling bridge (%d)\n", retval);
+	pci_set_master(bridge);
+}
+EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources);
+
+int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
+{
+	struct pci_dev_resource *dev_res;
+	struct pci_dev *next;
+	LIST_HEAD(saved);
+	LIST_HEAD(added);
+	LIST_HEAD(failed);
+	unsigned int i;
+	int ret;
+
+	down_read(&pci_bus_sem);
+
+	/* Walk to the root hub, releasing bridge BARs when possible */
+	next = bridge;
+	do {
+		bridge = next;
+		for (i = PCI_BRIDGE_RESOURCES; i < PCI_BRIDGE_RESOURCE_END;
+		     i++) {
+			struct resource *res = &bridge->resource[i];
+
+			if ((res->flags ^ type) & PCI_RES_TYPE_MASK)
+				continue;
+
+			/* Ignore BARs which are still in use */
+			if (res->child)
+				continue;
+
+			ret = add_to_list(&saved, bridge, res, 0, 0);
+			if (ret)
+				goto cleanup;
+
+			pci_info(bridge, "BAR %d: releasing %pR\n",
+				 i, res);
+
+			if (res->parent)
+				release_resource(res);
+			res->start = 0;
+			res->end = 0;
+			break;
+		}
+		if (i == PCI_BRIDGE_RESOURCE_END)
+			break;
+
+		next = bridge->bus ? bridge->bus->self : NULL;
+	} while (next);
+
+	if (list_empty(&saved)) {
+		up_read(&pci_bus_sem);
+		return -ENOENT;
+	}
+
+	__pci_bus_size_bridges(bridge->subordinate, &added);
+	__pci_bridge_assign_resources(bridge, &added, &failed);
+	BUG_ON(!list_empty(&added));
+
+	if (!list_empty(&failed)) {
+		ret = -ENOSPC;
+		goto cleanup;
+	}
+
+	list_for_each_entry(dev_res, &saved, list) {
+		/* Skip the bridge we just assigned resources for */
+		if (bridge == dev_res->dev)
+			continue;
+
+		bridge = dev_res->dev;
+		pci_setup_bridge(bridge->subordinate);
+	}
+
+	free_list(&saved);
+	up_read(&pci_bus_sem);
+	return 0;
+
+cleanup:
+	/* Restore size and flags */
+	list_for_each_entry(dev_res, &failed, list) {
+		struct resource *res = dev_res->res;
+
+		res->start = dev_res->start;
+		res->end = dev_res->end;
+		res->flags = dev_res->flags;
+	}
+	free_list(&failed);
+
+	/* Revert to the old configuration */
+	list_for_each_entry(dev_res, &saved, list) {
+		struct resource *res = dev_res->res;
+
+		bridge = dev_res->dev;
+		i = res - bridge->resource;
+
+		res->start = dev_res->start;
+		res->end = dev_res->end;
+		res->flags = dev_res->flags;
+
+		pci_claim_resource(bridge, i);
+		pci_setup_bridge(bridge->subordinate);
+	}
+	free_list(&saved);
+	up_read(&pci_bus_sem);
+
+	return ret;
+}
+
+void pci_assign_unassigned_bus_resources(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+	/* List of resources that want additional resources */
+	LIST_HEAD(add_list);
+
+	down_read(&pci_bus_sem);
+	for_each_pci_bridge(dev, bus)
+		if (pci_has_subordinate(dev))
+			__pci_bus_size_bridges(dev->subordinate, &add_list);
+	up_read(&pci_bus_sem);
+	__pci_bus_assign_resources(bus, &add_list, NULL);
+	BUG_ON(!list_empty(&add_list));
+}
+EXPORT_SYMBOL_GPL(pci_assign_unassigned_bus_resources);