Merge tag 'drm-misc-fixes-2020-03-18-1' of git://anongit.freedesktop.org/drm/drm...

[mirror_ubuntu-jammy-kernel.git] / drivers / pci / setup-bus.c

// 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;

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
 */
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("pdev_sort_resources(): kmalloc() failed!\n");
                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_RESOURCES + 0];
        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_RESOURCES + 1];
        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_RESOURCES + 2];
        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 - PCI_BRIDGE_RESOURCES) {
        case 0:
                pci_setup_bridge_io(bridge);
                break;
        case 1:
                pci_setup_bridge_mmio(bridge);
                break;
        case 2:
                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 = &bridge->resource[PCI_BRIDGE_RESOURCES];

        b_res[1].flags |= IORESOURCE_MEM;

        if (bridge->io_window)
                b_res[0].flags |= IORESOURCE_IO;

        if (bridge->pref_window) {
                b_res[2].flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH;
                if (bridge->pref_64_window) {
                        b_res[2].flags |= IORESOURCE_MEM_64;
                        b_res[2].flags |= 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->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 (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 (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 (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 (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 = &bridge->resource[PCI_BRIDGE_RESOURCES];
        resource_size_t b_res_3_size = pci_cardbus_mem_size * 2;
        u16 ctrl;

        if (b_res[0].parent)
                goto handle_b_res_1;
        /*
         * Reserve some resources for CardBus.  We reserve a fixed amount
         * of bus space for CardBus bridges.
         */
        b_res[0].start = pci_cardbus_io_size;
        b_res[0].end = b_res[0].start + pci_cardbus_io_size - 1;
        b_res[0].flags |= IORESOURCE_IO | IORESOURCE_STARTALIGN;
        if (realloc_head) {
                b_res[0].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:
        if (b_res[1].parent)
                goto handle_b_res_2;
        b_res[1].start = pci_cardbus_io_size;
        b_res[1].end = b_res[1].start + pci_cardbus_io_size - 1;
        b_res[1].flags |= IORESOURCE_IO | IORESOURCE_STARTALIGN;
        if (realloc_head) {
                b_res[1].end -= pci_cardbus_io_size;
                add_to_list(realloc_head, bridge, b_res+1, 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);
        }

        if (b_res[2].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[2].start = pci_cardbus_mem_size;
                b_res[2].end = b_res[2].start + pci_cardbus_mem_size - 1;
                b_res[2].flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH |
                                  IORESOURCE_STARTALIGN;
                if (realloc_head) {
                        b_res[2].end -= pci_cardbus_mem_size;
                        add_to_list(realloc_head, bridge, b_res+2,
                                 pci_cardbus_mem_size, pci_cardbus_mem_size);
                }

                /* Reduce that to half */
                b_res_3_size = pci_cardbus_mem_size;
        }

handle_b_res_3:
        if (b_res[3].parent)
                goto handle_done;
        b_res[3].start = pci_cardbus_mem_size;
        b_res[3].end = b_res[3].start + b_res_3_size - 1;
        b_res[3].flags |= IORESOURCE_MEM | IORESOURCE_STARTALIGN;
        if (realloc_head) {
                b_res[3].end -= b_res_3_size;
                add_to_list(realloc_head, bridge, b_res+3, 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 *b_res;
        int 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))
                return;

        switch (bus->self->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;
                }
                /* Fall through */
        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.
                 */
                b_res = &bus->self->resource[PCI_BRIDGE_RESOURCES];
                mask = IORESOURCE_MEM;
                prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH;
                if (b_res[2].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);
        }

        res->end = res->start + new_size - 1;
        remove_from_list(add_list, res);
}

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_hp, mmio_per_hp, mmio_pref_per_hp, align;

        io_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 0];
        mmio_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 1];
        mmio_pref_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 2];

        /*
         * 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++;
        }

        /*
         * There is only one bridge on the bus so it gets all available
         * resources which it can then distribute to the possible hotplug
         * bridges below.
         */
        if (hotplug_bridges + normal_bridges == 1) {
                dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
                if (dev->subordinate)
                        pci_bus_distribute_available_resources(dev->subordinate,
                                add_list, io, mmio, mmio_pref);
                return;
        }

        if (hotplug_bridges == 0)
                return;

        /*
         * Calculate the total amount of extra resource space we can
         * pass to bridges below this one.  This is basically the
         * extra space reduced by the minimal required space for the
         * non-hotplug bridges.
         */
        for_each_pci_bridge(dev, bus) {
                resource_size_t used_size;
                struct resource *res;

                if (dev->is_hotplug_bridge)
                        continue;

                /*
                 * Reduce the available resource space by what the
                 * bridge and devices below it occupy.
                 */
                res = &dev->resource[PCI_BRIDGE_RESOURCES + 0];
                align = pci_resource_alignment(dev, res);
                align = align ? ALIGN(io.start, align) - io.start : 0;
                used_size = align + resource_size(res);
                if (!res->parent)
                        io.start = min(io.start + used_size, io.end + 1);

                res = &dev->resource[PCI_BRIDGE_RESOURCES + 1];
                align = pci_resource_alignment(dev, res);
                align = align ? ALIGN(mmio.start, align) - mmio.start : 0;
                used_size = align + resource_size(res);
                if (!res->parent)
                        mmio.start = min(mmio.start + used_size, mmio.end + 1);

                res = &dev->resource[PCI_BRIDGE_RESOURCES + 2];
                align = pci_resource_alignment(dev, res);
                align = align ? ALIGN(mmio_pref.start, align) -
                        mmio_pref.start : 0;
                used_size = align + resource_size(res);
                if (!res->parent)
                        mmio_pref.start = min(mmio_pref.start + used_size,
                                mmio_pref.end + 1);
        }

        io_per_hp = div64_ul(resource_size(&io), hotplug_bridges);
        mmio_per_hp = div64_ul(resource_size(&mmio), hotplug_bridges);
        mmio_pref_per_hp = div64_ul(resource_size(&mmio_pref),
                hotplug_bridges);

        /*
         * Go over devices on this bus and distribute the remaining
         * resource space between hotplug bridges.
         */
        for_each_pci_bridge(dev, bus) {
                struct pci_bus *b;

                b = dev->subordinate;
                if (!b || !dev->is_hotplug_bridge)
                        continue;

                /*
                 * Distribute available extra resources equally between
                 * hotplug-capable downstream ports taking alignment into
                 * account.
                 */
                io.end = io.start + io_per_hp - 1;
                mmio.end = mmio.start + mmio_per_hp - 1;
                mmio_pref.end = mmio_pref.start + mmio_pref_per_hp - 1;

                pci_bus_distribute_available_resources(b, add_list, io, mmio,
                                                       mmio_pref);

                io.start += io_per_hp;
                mmio.start += mmio_per_hp;
                mmio_pref.start += mmio_pref_per_hp;
        }
}

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_RESOURCES + 0];
        available_mmio = bridge->resource[PCI_BRIDGE_RESOURCES + 1];
        available_mmio_pref = bridge->resource[PCI_BRIDGE_RESOURCES + 2];

        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);