[POWERPC] pci_controller->arch_data really is a struct device_node *

[deliverable/linux.git] / arch / powerpc / kernel / pci_32.c

/*
 * Common pmac/prep/chrp pci routines. -- Cort
 */

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/capability.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/bootmem.h>
#include <linux/irq.h>
#include <linux/list.h>

#include <asm/processor.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/pci-bridge.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
#include <asm/machdep.h>

#undef DEBUG

#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

unsigned long isa_io_base     = 0;
unsigned long isa_mem_base    = 0;
unsigned long pci_dram_offset = 0;
int pcibios_assign_bus_offset = 1;

void pcibios_make_OF_bus_map(void);

static int pci_relocate_bridge_resource(struct pci_bus *bus, int i);
static int probe_resource(struct pci_bus *parent, struct resource *pr,
                          struct resource *res, struct resource **conflict);
static void update_bridge_base(struct pci_bus *bus, int i);
static void pcibios_fixup_resources(struct pci_dev* dev);
static void fixup_broken_pcnet32(struct pci_dev* dev);
static int reparent_resources(struct resource *parent, struct resource *res);
static void fixup_cpc710_pci64(struct pci_dev* dev);
#ifdef CONFIG_PPC_OF
static u8* pci_to_OF_bus_map;
#endif

/* By default, we don't re-assign bus numbers. We do this only on
 * some pmacs
 */
int pci_assign_all_buses;

LIST_HEAD(hose_list);

static int pci_bus_count;

static void
fixup_hide_host_resource_fsl(struct pci_dev* dev)
{
        int i, class = dev->class >> 8;

        if ((class == PCI_CLASS_PROCESSOR_POWERPC) &&
                (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) &&
                (dev->bus->parent == NULL)) {
                for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
                        dev->resource[i].start = 0;
                        dev->resource[i].end = 0;
                        dev->resource[i].flags = 0;
                }
        }
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MOTOROLA, PCI_ANY_ID, fixup_hide_host_resource_fsl); 
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_FREESCALE, PCI_ANY_ID, fixup_hide_host_resource_fsl); 

static void
fixup_broken_pcnet32(struct pci_dev* dev)
{
        if ((dev->class>>8 == PCI_CLASS_NETWORK_ETHERNET)) {
                dev->vendor = PCI_VENDOR_ID_AMD;
                pci_write_config_word(dev, PCI_VENDOR_ID, PCI_VENDOR_ID_AMD);
        }
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_TRIDENT, PCI_ANY_ID,                     fixup_broken_pcnet32);

static void
fixup_cpc710_pci64(struct pci_dev* dev)
{
        /* Hide the PCI64 BARs from the kernel as their content doesn't
         * fit well in the resource management
         */
        dev->resource[0].start = dev->resource[0].end = 0;
        dev->resource[0].flags = 0;
        dev->resource[1].start = dev->resource[1].end = 0;
        dev->resource[1].flags = 0;
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_IBM,     PCI_DEVICE_ID_IBM_CPC710_PCI64, fixup_cpc710_pci64);

static void
pcibios_fixup_resources(struct pci_dev *dev)
{
        struct pci_controller* hose = (struct pci_controller *)dev->sysdata;
        int i;
        unsigned long offset;

        if (!hose) {
                printk(KERN_ERR "No hose for PCI dev %s!\n", pci_name(dev));
                return;
        }
        for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
                struct resource *res = dev->resource + i;
                if (!res->flags)
                        continue;
                if (res->end == 0xffffffff) {
                        DBG("PCI:%s Resource %d [%016llx-%016llx] is unassigned\n",
                            pci_name(dev), i, (u64)res->start, (u64)res->end);
                        res->end -= res->start;
                        res->start = 0;
                        res->flags |= IORESOURCE_UNSET;
                        continue;
                }
                offset = 0;
                if (res->flags & IORESOURCE_MEM) {
                        offset = hose->pci_mem_offset;
                } else if (res->flags & IORESOURCE_IO) {
                        offset = (unsigned long) hose->io_base_virt
                                - isa_io_base;
                }
                if (offset != 0) {
                        res->start += offset;
                        res->end += offset;
                        DBG("Fixup res %d (%lx) of dev %s: %llx -> %llx\n",
                            i, res->flags, pci_name(dev),
                            (u64)res->start - offset, (u64)res->start);
                }
        }

        /* Call machine specific resource fixup */
        if (ppc_md.pcibios_fixup_resources)
                ppc_md.pcibios_fixup_resources(dev);
}
DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID,            PCI_ANY_ID,                     pcibios_fixup_resources);

void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
                        struct resource *res)
{
        unsigned long offset = 0;
        struct pci_controller *hose = dev->sysdata;

        if (hose && res->flags & IORESOURCE_IO)
                offset = (unsigned long)hose->io_base_virt - isa_io_base;
        else if (hose && res->flags & IORESOURCE_MEM)
                offset = hose->pci_mem_offset;
        region->start = res->start - offset;
        region->end = res->end - offset;
}
EXPORT_SYMBOL(pcibios_resource_to_bus);

void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
                             struct pci_bus_region *region)
{
        unsigned long offset = 0;
        struct pci_controller *hose = dev->sysdata;

        if (hose && res->flags & IORESOURCE_IO)
                offset = (unsigned long)hose->io_base_virt - isa_io_base;
        else if (hose && res->flags & IORESOURCE_MEM)
                offset = hose->pci_mem_offset;
        res->start = region->start + offset;
        res->end = region->end + offset;
}
EXPORT_SYMBOL(pcibios_bus_to_resource);

/*
 * We need to avoid collisions with `mirrored' VGA ports
 * and other strange ISA hardware, so we always want the
 * addresses to be allocated in the 0x000-0x0ff region
 * modulo 0x400.
 *
 * Why? Because some silly external IO cards only decode
 * the low 10 bits of the IO address. The 0x00-0xff region
 * is reserved for motherboard devices that decode all 16
 * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
 * but we want to try to avoid allocating at 0x2900-0x2bff
 * which might have be mirrored at 0x0100-0x03ff..
 */
void pcibios_align_resource(void *data, struct resource *res,
                                resource_size_t size, resource_size_t align)
{
        struct pci_dev *dev = data;

        if (res->flags & IORESOURCE_IO) {
                resource_size_t start = res->start;

                if (size > 0x100) {
                        printk(KERN_ERR "PCI: I/O Region %s/%d too large"
                               " (%lld bytes)\n", pci_name(dev),
                               dev->resource - res, (unsigned long long)size);
                }

                if (start & 0x300) {
                        start = (start + 0x3ff) & ~0x3ff;
                        res->start = start;
                }
        }
}
EXPORT_SYMBOL(pcibios_align_resource);

/*
 *  Handle resources of PCI devices.  If the world were perfect, we could
 *  just allocate all the resource regions and do nothing more.  It isn't.
 *  On the other hand, we cannot just re-allocate all devices, as it would
 *  require us to know lots of host bridge internals.  So we attempt to
 *  keep as much of the original configuration as possible, but tweak it
 *  when it's found to be wrong.
 *
 *  Known BIOS problems we have to work around:
 *      - I/O or memory regions not configured
 *      - regions configured, but not enabled in the command register
 *      - bogus I/O addresses above 64K used
 *      - expansion ROMs left enabled (this may sound harmless, but given
 *        the fact the PCI specs explicitly allow address decoders to be
 *        shared between expansion ROMs and other resource regions, it's
 *        at least dangerous)
 *
 *  Our solution:
 *      (1) Allocate resources for all buses behind PCI-to-PCI bridges.
 *          This gives us fixed barriers on where we can allocate.
 *      (2) Allocate resources for all enabled devices.  If there is
 *          a collision, just mark the resource as unallocated. Also
 *          disable expansion ROMs during this step.
 *      (3) Try to allocate resources for disabled devices.  If the
 *          resources were assigned correctly, everything goes well,
 *          if they weren't, they won't disturb allocation of other
 *          resources.
 *      (4) Assign new addresses to resources which were either
 *          not configured at all or misconfigured.  If explicitly
 *          requested by the user, configure expansion ROM address
 *          as well.
 */

static void __init
pcibios_allocate_bus_resources(struct list_head *bus_list)
{
        struct pci_bus *bus;
        int i;
        struct resource *res, *pr;

        /* Depth-First Search on bus tree */
        list_for_each_entry(bus, bus_list, node) {
                for (i = 0; i < 4; ++i) {
                        if ((res = bus->resource[i]) == NULL || !res->flags
                            || res->start > res->end)
                                continue;
                        if (bus->parent == NULL)
                                pr = (res->flags & IORESOURCE_IO)?
                                        &ioport_resource: &iomem_resource;
                        else {
                                pr = pci_find_parent_resource(bus->self, res);
                                if (pr == res) {
                                        /* this happens when the generic PCI
                                         * code (wrongly) decides that this
                                         * bridge is transparent  -- paulus
                                         */
                                        continue;
                                }
                        }

                        DBG("PCI: bridge rsrc %llx..%llx (%lx), parent %p\n",
                            (u64)res->start, (u64)res->end, res->flags, pr);
                        if (pr) {
                                if (request_resource(pr, res) == 0)
                                        continue;
                                /*
                                 * Must be a conflict with an existing entry.
                                 * Move that entry (or entries) under the
                                 * bridge resource and try again.
                                 */
                                if (reparent_resources(pr, res) == 0)
                                        continue;
                        }
                        printk(KERN_ERR "PCI: Cannot allocate resource region "
                               "%d of PCI bridge %d\n", i, bus->number);
                        if (pci_relocate_bridge_resource(bus, i))
                                bus->resource[i] = NULL;
                }
                pcibios_allocate_bus_resources(&bus->children);
        }
}

/*
 * Reparent resource children of pr that conflict with res
 * under res, and make res replace those children.
 */
static int __init
reparent_resources(struct resource *parent, struct resource *res)
{
        struct resource *p, **pp;
        struct resource **firstpp = NULL;

        for (pp = &parent->child; (p = *pp) != NULL; pp = &p->sibling) {
                if (p->end < res->start)
                        continue;
                if (res->end < p->start)
                        break;
                if (p->start < res->start || p->end > res->end)
                        return -1;      /* not completely contained */
                if (firstpp == NULL)
                        firstpp = pp;
        }
        if (firstpp == NULL)
                return -1;      /* didn't find any conflicting entries? */
        res->parent = parent;
        res->child = *firstpp;
        res->sibling = *pp;
        *firstpp = res;
        *pp = NULL;
        for (p = res->child; p != NULL; p = p->sibling) {
                p->parent = res;
                DBG(KERN_INFO "PCI: reparented %s [%llx..%llx] under %s\n",
                    p->name, (u64)p->start, (u64)p->end, res->name);
        }
        return 0;
}

/*
 * A bridge has been allocated a range which is outside the range
 * of its parent bridge, so it needs to be moved.
 */
static int __init
pci_relocate_bridge_resource(struct pci_bus *bus, int i)
{
        struct resource *res, *pr, *conflict;
        unsigned long try, size;
        int j;
        struct pci_bus *parent = bus->parent;

        if (parent == NULL) {
                /* shouldn't ever happen */
                printk(KERN_ERR "PCI: can't move host bridge resource\n");
                return -1;
        }
        res = bus->resource[i];
        if (res == NULL)
                return -1;
        pr = NULL;
        for (j = 0; j < 4; j++) {
                struct resource *r = parent->resource[j];
                if (!r)
                        continue;
                if ((res->flags ^ r->flags) & (IORESOURCE_IO | IORESOURCE_MEM))
                        continue;
                if (!((res->flags ^ r->flags) & IORESOURCE_PREFETCH)) {
                        pr = r;
                        break;
                }
                if (res->flags & IORESOURCE_PREFETCH)
                        pr = r;
        }
        if (pr == NULL)
                return -1;
        size = res->end - res->start;
        if (pr->start > pr->end || size > pr->end - pr->start)
                return -1;
        try = pr->end;
        for (;;) {
                res->start = try - size;
                res->end = try;
                if (probe_resource(bus->parent, pr, res, &conflict) == 0)
                        break;
                if (conflict->start <= pr->start + size)
                        return -1;
                try = conflict->start - 1;
        }
        if (request_resource(pr, res)) {
                DBG(KERN_ERR "PCI: huh? couldn't move to %llx..%llx\n",
                    (u64)res->start, (u64)res->end);
                return -1;              /* "can't happen" */
        }
        update_bridge_base(bus, i);
        printk(KERN_INFO "PCI: bridge %d resource %d moved to %llx..%llx\n",
               bus->number, i, (unsigned long long)res->start,
               (unsigned long long)res->end);
        return 0;
}

static int __init
probe_resource(struct pci_bus *parent, struct resource *pr,
               struct resource *res, struct resource **conflict)
{
        struct pci_bus *bus;
        struct pci_dev *dev;
        struct resource *r;
        int i;

        for (r = pr->child; r != NULL; r = r->sibling) {
                if (r->end >= res->start && res->end >= r->start) {
                        *conflict = r;
                        return 1;
                }
        }
        list_for_each_entry(bus, &parent->children, node) {
                for (i = 0; i < 4; ++i) {
                        if ((r = bus->resource[i]) == NULL)
                                continue;
                        if (!r->flags || r->start > r->end || r == res)
                                continue;
                        if (pci_find_parent_resource(bus->self, r) != pr)
                                continue;
                        if (r->end >= res->start && res->end >= r->start) {
                                *conflict = r;
                                return 1;
                        }
                }
        }
        list_for_each_entry(dev, &parent->devices, bus_list) {
                for (i = 0; i < 6; ++i) {
                        r = &dev->resource[i];
                        if (!r->flags || (r->flags & IORESOURCE_UNSET))
                                continue;
                        if (pci_find_parent_resource(dev, r) != pr)
                                continue;
                        if (r->end >= res->start && res->end >= r->start) {
                                *conflict = r;
                                return 1;
                        }
                }
        }
        return 0;
}

void __init
update_bridge_resource(struct pci_dev *dev, struct resource *res)
{
        u8 io_base_lo, io_limit_lo;
        u16 mem_base, mem_limit;
        u16 cmd;
        unsigned long start, end, off;
        struct pci_controller *hose = dev->sysdata;

        if (!hose) {
                printk("update_bridge_base: no hose?\n");
                return;
        }
        pci_read_config_word(dev, PCI_COMMAND, &cmd);
        pci_write_config_word(dev, PCI_COMMAND,
                              cmd & ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY));
        if (res->flags & IORESOURCE_IO) {
                off = (unsigned long) hose->io_base_virt - isa_io_base;
                start = res->start - off;
                end = res->end - off;
                io_base_lo = (start >> 8) & PCI_IO_RANGE_MASK;
                io_limit_lo = (end >> 8) & PCI_IO_RANGE_MASK;
                if (end > 0xffff)
                        io_base_lo |= PCI_IO_RANGE_TYPE_32;
                else
                        io_base_lo |= PCI_IO_RANGE_TYPE_16;
                pci_write_config_word(dev, PCI_IO_BASE_UPPER16,
                                start >> 16);
                pci_write_config_word(dev, PCI_IO_LIMIT_UPPER16,
                                end >> 16);
                pci_write_config_byte(dev, PCI_IO_BASE, io_base_lo);
                pci_write_config_byte(dev, PCI_IO_LIMIT, io_limit_lo);

        } else if ((res->flags & (IORESOURCE_MEM | IORESOURCE_PREFETCH))
                   == IORESOURCE_MEM) {
                off = hose->pci_mem_offset;
                mem_base = ((res->start - off) >> 16) & PCI_MEMORY_RANGE_MASK;
                mem_limit = ((res->end - off) >> 16) & PCI_MEMORY_RANGE_MASK;
                pci_write_config_word(dev, PCI_MEMORY_BASE, mem_base);
                pci_write_config_word(dev, PCI_MEMORY_LIMIT, mem_limit);

        } else if ((res->flags & (IORESOURCE_MEM | IORESOURCE_PREFETCH))
                   == (IORESOURCE_MEM | IORESOURCE_PREFETCH)) {
                off = hose->pci_mem_offset;
                mem_base = ((res->start - off) >> 16) & PCI_PREF_RANGE_MASK;
                mem_limit = ((res->end - off) >> 16) & PCI_PREF_RANGE_MASK;
                pci_write_config_word(dev, PCI_PREF_MEMORY_BASE, mem_base);
                pci_write_config_word(dev, PCI_PREF_MEMORY_LIMIT, mem_limit);

        } else {
                DBG(KERN_ERR "PCI: ugh, bridge %s res has flags=%lx\n",
                    pci_name(dev), res->flags);
        }
        pci_write_config_word(dev, PCI_COMMAND, cmd);
}

static void __init
update_bridge_base(struct pci_bus *bus, int i)
{
        struct resource *res = bus->resource[i];
        struct pci_dev *dev = bus->self;
        update_bridge_resource(dev, res);
}

static inline void alloc_resource(struct pci_dev *dev, int idx)
{
        struct resource *pr, *r = &dev->resource[idx];

        DBG("PCI:%s: Resource %d: %016llx-%016llx (f=%lx)\n",
            pci_name(dev), idx, (u64)r->start, (u64)r->end, r->flags);
        pr = pci_find_parent_resource(dev, r);
        if (!pr || request_resource(pr, r) < 0) {
                printk(KERN_ERR "PCI: Cannot allocate resource region %d"
                       " of device %s\n", idx, pci_name(dev));
                if (pr)
                        DBG("PCI:  parent is %p: %016llx-%016llx (f=%lx)\n",
                            pr, (u64)pr->start, (u64)pr->end, pr->flags);
                /* We'll assign a new address later */
                r->flags |= IORESOURCE_UNSET;
                r->end -= r->start;
                r->start = 0;
        }
}

static void __init
pcibios_allocate_resources(int pass)
{
        struct pci_dev *dev = NULL;
        int idx, disabled;
        u16 command;
        struct resource *r;

        for_each_pci_dev(dev) {
                pci_read_config_word(dev, PCI_COMMAND, &command);
                for (idx = 0; idx < 6; idx++) {
                        r = &dev->resource[idx];
                        if (r->parent)          /* Already allocated */
                                continue;
                        if (!r->flags || (r->flags & IORESOURCE_UNSET))
                                continue;       /* Not assigned at all */
                        if (r->flags & IORESOURCE_IO)
                                disabled = !(command & PCI_COMMAND_IO);
                        else
                                disabled = !(command & PCI_COMMAND_MEMORY);
                        if (pass == disabled)
                                alloc_resource(dev, idx);
                }
                if (pass)
                        continue;
                r = &dev->resource[PCI_ROM_RESOURCE];
                if (r->flags & IORESOURCE_ROM_ENABLE) {
                        /* Turn the ROM off, leave the resource region, but keep it unregistered. */
                        u32 reg;
                        DBG("PCI: Switching off ROM of %s\n", pci_name(dev));
                        r->flags &= ~IORESOURCE_ROM_ENABLE;
                        pci_read_config_dword(dev, dev->rom_base_reg, &reg);
                        pci_write_config_dword(dev, dev->rom_base_reg,
                                               reg & ~PCI_ROM_ADDRESS_ENABLE);
                }
        }
}

static void __init
pcibios_assign_resources(void)
{
        struct pci_dev *dev = NULL;
        int idx;
        struct resource *r;

        for_each_pci_dev(dev) {
                int class = dev->class >> 8;

                /* Don't touch classless devices and host bridges */
                if (!class || class == PCI_CLASS_BRIDGE_HOST)
                        continue;

                for (idx = 0; idx < 6; idx++) {
                        r = &dev->resource[idx];

                        /*
                         * We shall assign a new address to this resource,
                         * either because the BIOS (sic) forgot to do so
                         * or because we have decided the old address was
                         * unusable for some reason.
                         */
                        if ((r->flags & IORESOURCE_UNSET) && r->end &&
                            (!ppc_md.pcibios_enable_device_hook ||
                             !ppc_md.pcibios_enable_device_hook(dev, 1))) {
                                int rc;

                                r->flags &= ~IORESOURCE_UNSET;
                                rc = pci_assign_resource(dev, idx);
                                BUG_ON(rc);
                        }
                }

#if 0 /* don't assign ROMs */
                r = &dev->resource[PCI_ROM_RESOURCE];
                r->end -= r->start;
                r->start = 0;
                if (r->end)
                        pci_assign_resource(dev, PCI_ROM_RESOURCE);
#endif
        }
}

#ifdef CONFIG_PPC_OF
/*
 * Functions below are used on OpenFirmware machines.
 */
static void
make_one_node_map(struct device_node* node, u8 pci_bus)
{
        const int *bus_range;
        int len;

        if (pci_bus >= pci_bus_count)
                return;
        bus_range = of_get_property(node, "bus-range", &len);
        if (bus_range == NULL || len < 2 * sizeof(int)) {
                printk(KERN_WARNING "Can't get bus-range for %s, "
                       "assuming it starts at 0\n", node->full_name);
                pci_to_OF_bus_map[pci_bus] = 0;
        } else
                pci_to_OF_bus_map[pci_bus] = bus_range[0];

        for (node=node->child; node != 0;node = node->sibling) {
                struct pci_dev* dev;
                const unsigned int *class_code, *reg;
        
                class_code = of_get_property(node, "class-code", NULL);
                if (!class_code || ((*class_code >> 8) != PCI_CLASS_BRIDGE_PCI &&
                        (*class_code >> 8) != PCI_CLASS_BRIDGE_CARDBUS))
                        continue;
                reg = of_get_property(node, "reg", NULL);
                if (!reg)
                        continue;
                dev = pci_get_bus_and_slot(pci_bus, ((reg[0] >> 8) & 0xff));
                if (!dev || !dev->subordinate) {
                        pci_dev_put(dev);
                        continue;
                }
                make_one_node_map(node, dev->subordinate->number);
                pci_dev_put(dev);
        }
}
        
void
pcibios_make_OF_bus_map(void)
{
        int i;
        struct pci_controller *hose, *tmp;
        struct property *map_prop;
        struct device_node *dn;

        pci_to_OF_bus_map = kmalloc(pci_bus_count, GFP_KERNEL);
        if (!pci_to_OF_bus_map) {
                printk(KERN_ERR "Can't allocate OF bus map !\n");
                return;
        }

        /* We fill the bus map with invalid values, that helps
         * debugging.
         */
        for (i=0; i<pci_bus_count; i++)
                pci_to_OF_bus_map[i] = 0xff;

        /* For each hose, we begin searching bridges */
        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
                struct device_node* node = hose->dn;

                if (!node)
                        continue;
                make_one_node_map(node, hose->first_busno);
        }
        dn = of_find_node_by_path("/");
        map_prop = of_find_property(dn, "pci-OF-bus-map", NULL);
        if (map_prop) {
                BUG_ON(pci_bus_count > map_prop->length);
                memcpy(map_prop->value, pci_to_OF_bus_map, pci_bus_count);
        }
        of_node_put(dn);
#ifdef DEBUG
        printk("PCI->OF bus map:\n");
        for (i=0; i<pci_bus_count; i++) {
                if (pci_to_OF_bus_map[i] == 0xff)
                        continue;
                printk("%d -> %d\n", i, pci_to_OF_bus_map[i]);
        }
#endif
}

typedef int (*pci_OF_scan_iterator)(struct device_node* node, void* data);

static struct device_node*
scan_OF_pci_childs(struct device_node* node, pci_OF_scan_iterator filter, void* data)
{
        struct device_node* sub_node;

        for (; node != 0;node = node->sibling) {
                const unsigned int *class_code;
        
                if (filter(node, data))
                        return node;

                /* For PCI<->PCI bridges or CardBus bridges, we go down
                 * Note: some OFs create a parent node "multifunc-device" as
                 * a fake root for all functions of a multi-function device,
                 * we go down them as well.
                 */
                class_code = of_get_property(node, "class-code", NULL);
                if ((!class_code || ((*class_code >> 8) != PCI_CLASS_BRIDGE_PCI &&
                        (*class_code >> 8) != PCI_CLASS_BRIDGE_CARDBUS)) &&
                        strcmp(node->name, "multifunc-device"))
                        continue;
                sub_node = scan_OF_pci_childs(node->child, filter, data);
                if (sub_node)
                        return sub_node;
        }
        return NULL;
}

static struct device_node *scan_OF_for_pci_dev(struct device_node *parent,
                                               unsigned int devfn)
{
        struct device_node *np = NULL;
        const u32 *reg;
        unsigned int psize;

        while ((np = of_get_next_child(parent, np)) != NULL) {
                reg = of_get_property(np, "reg", &psize);
                if (reg == NULL || psize < 4)
                        continue;
                if (((reg[0] >> 8) & 0xff) == devfn)
                        return np;
        }
        return NULL;
}


static struct device_node *scan_OF_for_pci_bus(struct pci_bus *bus)
{
        struct device_node *parent, *np;

        /* Are we a root bus ? */
        if (bus->self == NULL || bus->parent == NULL) {
                struct pci_controller *hose = pci_bus_to_host(bus);
                if (hose == NULL)
                        return NULL;
                return of_node_get(hose->dn);
        }

        /* not a root bus, we need to get our parent */
        parent = scan_OF_for_pci_bus(bus->parent);
        if (parent == NULL)
                return NULL;

        /* now iterate for children for a match */
        np = scan_OF_for_pci_dev(parent, bus->self->devfn);
        of_node_put(parent);

        return np;
}

/*
 * Scans the OF tree for a device node matching a PCI device
 */
struct device_node *
pci_busdev_to_OF_node(struct pci_bus *bus, int devfn)
{
        struct device_node *parent, *np;

        if (!have_of)
                return NULL;

        DBG("pci_busdev_to_OF_node(%d,0x%x)\n", bus->number, devfn);
        parent = scan_OF_for_pci_bus(bus);
        if (parent == NULL)
                return NULL;
        DBG(" parent is %s\n", parent ? parent->full_name : "<NULL>");
        np = scan_OF_for_pci_dev(parent, devfn);
        of_node_put(parent);
        DBG(" result is %s\n", np ? np->full_name : "<NULL>");

        /* XXX most callers don't release the returned node
         * mostly because ppc64 doesn't increase the refcount,
         * we need to fix that.
         */
        return np;
}
EXPORT_SYMBOL(pci_busdev_to_OF_node);

struct device_node*
pci_device_to_OF_node(struct pci_dev *dev)
{
        return pci_busdev_to_OF_node(dev->bus, dev->devfn);
}
EXPORT_SYMBOL(pci_device_to_OF_node);

static int
find_OF_pci_device_filter(struct device_node* node, void* data)
{
        return ((void *)node == data);
}

/*
 * Returns the PCI device matching a given OF node
 */
int
pci_device_from_OF_node(struct device_node* node, u8* bus, u8* devfn)
{
        const unsigned int *reg;
        struct pci_controller* hose;
        struct pci_dev* dev = NULL;
        
        if (!have_of)
                return -ENODEV;
        /* Make sure it's really a PCI device */
        hose = pci_find_hose_for_OF_device(node);
        if (!hose || !hose->dn)
                return -ENODEV;
        if (!scan_OF_pci_childs(hose->dn->child,
                        find_OF_pci_device_filter, (void *)node))
                return -ENODEV;
        reg = of_get_property(node, "reg", NULL);
        if (!reg)
                return -ENODEV;
        *bus = (reg[0] >> 16) & 0xff;
        *devfn = ((reg[0] >> 8) & 0xff);

        /* Ok, here we need some tweak. If we have already renumbered
         * all busses, we can't rely on the OF bus number any more.
         * the pci_to_OF_bus_map is not enough as several PCI busses
         * may match the same OF bus number.
         */
        if (!pci_to_OF_bus_map)
                return 0;

        for_each_pci_dev(dev)
                if (pci_to_OF_bus_map[dev->bus->number] == *bus &&
                                dev->devfn == *devfn) {
                        *bus = dev->bus->number;
                        pci_dev_put(dev);
                        return 0;
                }

        return -ENODEV;
}
EXPORT_SYMBOL(pci_device_from_OF_node);

void __init
pci_process_bridge_OF_ranges(struct pci_controller *hose,
                           struct device_node *dev, int primary)
{
        static unsigned int static_lc_ranges[256] __initdata;
        const unsigned int *dt_ranges;
        unsigned int *lc_ranges, *ranges, *prev, size;
        int rlen = 0, orig_rlen;
        int memno = 0;
        struct resource *res;
        int np, na = of_n_addr_cells(dev);
        np = na + 5;

        /* First we try to merge ranges to fix a problem with some pmacs
         * that can have more than 3 ranges, fortunately using contiguous
         * addresses -- BenH
         */
        dt_ranges = of_get_property(dev, "ranges", &rlen);
        if (!dt_ranges)
                return;
        /* Sanity check, though hopefully that never happens */
        if (rlen > sizeof(static_lc_ranges)) {
                printk(KERN_WARNING "OF ranges property too large !\n");
                rlen = sizeof(static_lc_ranges);
        }
        lc_ranges = static_lc_ranges;
        memcpy(lc_ranges, dt_ranges, rlen);
        orig_rlen = rlen;

        /* Let's work on a copy of the "ranges" property instead of damaging
         * the device-tree image in memory
         */
        ranges = lc_ranges;
        prev = NULL;
        while ((rlen -= np * sizeof(unsigned int)) >= 0) {
                if (prev) {
                        if (prev[0] == ranges[0] && prev[1] == ranges[1] &&
                                (prev[2] + prev[na+4]) == ranges[2] &&
                                (prev[na+2] + prev[na+4]) == ranges[na+2]) {
                                prev[na+4] += ranges[na+4];
                                ranges[0] = 0;
                                ranges += np;
                                continue;
                        }
                }
                prev = ranges;
                ranges += np;
        }

        /*
         * The ranges property is laid out as an array of elements,
         * each of which comprises:
         *   cells 0 - 2:       a PCI address
         *   cells 3 or 3+4:    a CPU physical address
         *                      (size depending on dev->n_addr_cells)
         *   cells 4+5 or 5+6:  the size of the range
         */
        ranges = lc_ranges;
        rlen = orig_rlen;
        while (ranges && (rlen -= np * sizeof(unsigned int)) >= 0) {
                res = NULL;
                size = ranges[na+4];
                switch ((ranges[0] >> 24) & 0x3) {
                case 1:         /* I/O space */
                        if (ranges[2] != 0)
                                break;
                        hose->io_base_phys = ranges[na+2];
                        /* limit I/O space to 16MB */
                        if (size > 0x01000000)
                                size = 0x01000000;
                        hose->io_base_virt = ioremap(ranges[na+2], size);
                        if (primary)
                                isa_io_base = (unsigned long) hose->io_base_virt;
                        res = &hose->io_resource;
                        res->flags = IORESOURCE_IO;
                        res->start = ranges[2];
                        DBG("PCI: IO 0x%llx -> 0x%llx\n",
                            (u64)res->start, (u64)res->start + size - 1);
                        break;
                case 2:         /* memory space */
                        memno = 0;
                        if (ranges[1] == 0 && ranges[2] == 0
                            && ranges[na+4] <= (16 << 20)) {
                                /* 1st 16MB, i.e. ISA memory area */
                                if (primary)
                                        isa_mem_base = ranges[na+2];
                                memno = 1;
                        }
                        while (memno < 3 && hose->mem_resources[memno].flags)
                                ++memno;
                        if (memno == 0)
                                hose->pci_mem_offset = ranges[na+2] - ranges[2];
                        if (memno < 3) {
                                res = &hose->mem_resources[memno];
                                res->flags = IORESOURCE_MEM;
                                if(ranges[0] & 0x40000000)
                                        res->flags |= IORESOURCE_PREFETCH;
                                res->start = ranges[na+2];
                                DBG("PCI: MEM[%d] 0x%llx -> 0x%llx\n", memno,
                                    (u64)res->start, (u64)res->start + size - 1);
                        }
                        break;
                }
                if (res != NULL) {
                        res->name = dev->full_name;
                        res->end = res->start + size - 1;
                        res->parent = NULL;
                        res->sibling = NULL;
                        res->child = NULL;
                }
                ranges += np;
        }
}

/* We create the "pci-OF-bus-map" property now so it appears in the
 * /proc device tree
 */
void __init
pci_create_OF_bus_map(void)
{
        struct property* of_prop;
        struct device_node *dn;

        of_prop = (struct property*) alloc_bootmem(sizeof(struct property) + 256);
        if (!of_prop)
                return;
        dn = of_find_node_by_path("/");
        if (dn) {
                memset(of_prop, -1, sizeof(struct property) + 256);
                of_prop->name = "pci-OF-bus-map";
                of_prop->length = 256;
                of_prop->value = &of_prop[1];
                prom_add_property(dn, of_prop);
                of_node_put(dn);
        }
}

#else /* CONFIG_PPC_OF */
void pcibios_make_OF_bus_map(void)
{
}
#endif /* CONFIG_PPC_OF */

#ifdef CONFIG_PPC_PMAC
/*
 * This set of routines checks for PCI<->PCI bridges that have closed
 * IO resources and have child devices. It tries to re-open an IO
 * window on them.
 *
 * This is a _temporary_ fix to workaround a problem with Apple's OF
 * closing IO windows on P2P bridges when the OF drivers of cards
 * below this bridge don't claim any IO range (typically ATI or
 * Adaptec).
 *
 * A more complete fix would be to use drivers/pci/setup-bus.c, which
 * involves a working pcibios_fixup_pbus_ranges(), some more care about
 * ordering when creating the host bus resources, and maybe a few more
 * minor tweaks
 */

/* Initialize bridges with base/limit values we have collected */
static void __init
do_update_p2p_io_resource(struct pci_bus *bus, int enable_vga)
{
        struct pci_dev *bridge = bus->self;
        struct pci_controller* hose = (struct pci_controller *)bridge->sysdata;
        u32 l;
        u16 w;
        struct resource res;

        if (bus->resource[0] == NULL)
                return;
        res = *(bus->resource[0]);

        DBG("Remapping Bus %d, bridge: %s\n", bus->number, pci_name(bridge));
        res.start -= ((unsigned long) hose->io_base_virt - isa_io_base);
        res.end -= ((unsigned long) hose->io_base_virt - isa_io_base);
        DBG("  IO window: %016llx-%016llx\n", res.start, res.end);

        /* Set up the top and bottom of the PCI I/O segment for this bus. */
        pci_read_config_dword(bridge, PCI_IO_BASE, &l);
        l &= 0xffff000f;
        l |= (res.start >> 8) & 0x00f0;
        l |= res.end & 0xf000;
        pci_write_config_dword(bridge, PCI_IO_BASE, l);

        if ((l & PCI_IO_RANGE_TYPE_MASK) == PCI_IO_RANGE_TYPE_32) {
                l = (res.start >> 16) | (res.end & 0xffff0000);
                pci_write_config_dword(bridge, PCI_IO_BASE_UPPER16, l);
        }

        pci_read_config_word(bridge, PCI_COMMAND, &w);
        w |= PCI_COMMAND_IO;
        pci_write_config_word(bridge, PCI_COMMAND, w);

#if 0 /* Enabling this causes XFree 4.2.0 to hang during PCI probe */
        if (enable_vga) {
                pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &w);
                w |= PCI_BRIDGE_CTL_VGA;
                pci_write_config_word(bridge, PCI_BRIDGE_CONTROL, w);
        }
#endif
}

/* This function is pretty basic and actually quite broken for the
 * general case, it's enough for us right now though. It's supposed
 * to tell us if we need to open an IO range at all or not and what
 * size.
 */
static int __init
check_for_io_childs(struct pci_bus *bus, struct resource* res, int *found_vga)
{
        struct pci_dev *dev;
        int     i;
        int     rc = 0;

#define push_end(res, mask) do {                \
        BUG_ON((mask+1) & mask);                \
        res->end = (res->end + mask) | mask;    \
} while (0)

        list_for_each_entry(dev, &bus->devices, bus_list) {
                u16 class = dev->class >> 8;

                if (class == PCI_CLASS_DISPLAY_VGA ||
                    class == PCI_CLASS_NOT_DEFINED_VGA)
                        *found_vga = 1;
                if (class >> 8 == PCI_BASE_CLASS_BRIDGE && dev->subordinate)
                        rc |= check_for_io_childs(dev->subordinate, res, found_vga);
                if (class == PCI_CLASS_BRIDGE_CARDBUS)
                        push_end(res, 0xfff);

                for (i=0; i<PCI_NUM_RESOURCES; i++) {
                        struct resource *r;
                        unsigned long r_size;

                        if (dev->class >> 8 == PCI_CLASS_BRIDGE_PCI
                            && i >= PCI_BRIDGE_RESOURCES)
                                continue;
                        r = &dev->resource[i];
                        r_size = r->end - r->start;
                        if (r_size < 0xfff)
                                r_size = 0xfff;
                        if (r->flags & IORESOURCE_IO && (r_size) != 0) {
                                rc = 1;
                                push_end(res, r_size);
                        }
                }
        }

        return rc;
}

/* Here we scan all P2P bridges of a given level that have a closed
 * IO window. Note that the test for the presence of a VGA card should
 * be improved to take into account already configured P2P bridges,
 * currently, we don't see them and might end up configuring 2 bridges
 * with VGA pass through enabled
 */
static void __init
do_fixup_p2p_level(struct pci_bus *bus)
{
        struct pci_bus *b;
        int i, parent_io;
        int has_vga = 0;

        for (parent_io=0; parent_io<4; parent_io++)
                if (bus->resource[parent_io]
                    && bus->resource[parent_io]->flags & IORESOURCE_IO)
                        break;
        if (parent_io >= 4)
                return;

        list_for_each_entry(b, &bus->children, node) {
                struct pci_dev *d = b->self;
                struct pci_controller* hose = (struct pci_controller *)d->sysdata;
                struct resource *res = b->resource[0];
                struct resource tmp_res;
                unsigned long max;
                int found_vga = 0;

                memset(&tmp_res, 0, sizeof(tmp_res));
                tmp_res.start = bus->resource[parent_io]->start;

                /* We don't let low addresses go through that closed P2P bridge, well,
                 * that may not be necessary but I feel safer that way
                 */
                if (tmp_res.start == 0)
                        tmp_res.start = 0x1000;
        
                if (!list_empty(&b->devices) && res && res->flags == 0 &&
                    res != bus->resource[parent_io] &&
                    (d->class >> 8) == PCI_CLASS_BRIDGE_PCI &&
                    check_for_io_childs(b, &tmp_res, &found_vga)) {
                        u8 io_base_lo;

                        printk(KERN_INFO "Fixing up IO bus %s\n", b->name);

                        if (found_vga) {
                                if (has_vga) {
                                        printk(KERN_WARNING "Skipping VGA, already active"
                                            " on bus segment\n");
                                        found_vga = 0;
                                } else
                                        has_vga = 1;
                        }
                        pci_read_config_byte(d, PCI_IO_BASE, &io_base_lo);

                        if ((io_base_lo & PCI_IO_RANGE_TYPE_MASK) == PCI_IO_RANGE_TYPE_32)
                                max = ((unsigned long) hose->io_base_virt
                                        - isa_io_base) + 0xffffffff;
                        else
                                max = ((unsigned long) hose->io_base_virt
                                        - isa_io_base) + 0xffff;

                        *res = tmp_res;
                        res->flags = IORESOURCE_IO;
                        res->name = b->name;
                
                        /* Find a resource in the parent where we can allocate */
                        for (i = 0 ; i < 4; i++) {
                                struct resource *r = bus->resource[i];
                                if (!r)
                                        continue;
                                if ((r->flags & IORESOURCE_IO) == 0)
                                        continue;
                                DBG("Trying to allocate from %016llx, size %016llx from parent"
                                    " res %d: %016llx -> %016llx\n",
                                        res->start, res->end, i, r->start, r->end);
                        
                                if (allocate_resource(r, res, res->end + 1, res->start, max,
                                    res->end + 1, NULL, NULL) < 0) {
                                        DBG("Failed !\n");
                                        continue;
                                }
                                do_update_p2p_io_resource(b, found_vga);
                                break;
                        }
                }
                do_fixup_p2p_level(b);
        }
}

static void
pcibios_fixup_p2p_bridges(void)
{
        struct pci_bus *b;

        list_for_each_entry(b, &pci_root_buses, node)
                do_fixup_p2p_level(b);
}

#endif /* CONFIG_PPC_PMAC */

static int __init
pcibios_init(void)
{
        struct pci_controller *hose, *tmp;
        struct pci_bus *bus;
        int next_busno = 0;

        printk(KERN_INFO "PCI: Probing PCI hardware\n");

        /* Scan all of the recorded PCI controllers.  */
        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
                if (pci_assign_all_buses)
                        hose->first_busno = next_busno;
                hose->last_busno = 0xff;
                bus = pci_scan_bus_parented(hose->parent, hose->first_busno,
                                            hose->ops, hose);
                if (bus)
                        pci_bus_add_devices(bus);
                hose->last_busno = bus->subordinate;
                if (pci_assign_all_buses || next_busno <= hose->last_busno)
                        next_busno = hose->last_busno + pcibios_assign_bus_offset;
        }
        pci_bus_count = next_busno;

        /* OpenFirmware based machines need a map of OF bus
         * numbers vs. kernel bus numbers since we may have to
         * remap them.
         */
        if (pci_assign_all_buses && have_of)
                pcibios_make_OF_bus_map();

        /* Call machine dependent fixup */
        if (ppc_md.pcibios_fixup)
                ppc_md.pcibios_fixup();

        /* Allocate and assign resources */
        pcibios_allocate_bus_resources(&pci_root_buses);
        pcibios_allocate_resources(0);
        pcibios_allocate_resources(1);
#ifdef CONFIG_PPC_PMAC
        pcibios_fixup_p2p_bridges();
#endif /* CONFIG_PPC_PMAC */
        pcibios_assign_resources();

        /* Call machine dependent post-init code */
        if (ppc_md.pcibios_after_init)
                ppc_md.pcibios_after_init();

        return 0;
}

subsys_initcall(pcibios_init);

void pcibios_fixup_bus(struct pci_bus *bus)
{
        struct pci_controller *hose = (struct pci_controller *) bus->sysdata;
        unsigned long io_offset;
        struct resource *res;
        struct pci_dev *dev;
        int i;

        io_offset = (unsigned long)hose->io_base_virt - isa_io_base;
        if (bus->parent == NULL) {
                /* This is a host bridge - fill in its resources */
                hose->bus = bus;

                bus->resource[0] = res = &hose->io_resource;
                if (!res->flags) {
                        if (io_offset)
                                printk(KERN_ERR "I/O resource not set for host"
                                       " bridge %d\n", hose->global_number);
                        res->start = 0;
                        res->end = IO_SPACE_LIMIT;
                        res->flags = IORESOURCE_IO;
                }
                res->start += io_offset;
                res->end += io_offset;

                for (i = 0; i < 3; ++i) {
                        res = &hose->mem_resources[i];
                        if (!res->flags) {
                                if (i > 0)
                                        continue;
                                printk(KERN_ERR "Memory resource not set for "
                                       "host bridge %d\n", hose->global_number);
                                res->start = hose->pci_mem_offset;
                                res->end = ~0U;
                                res->flags = IORESOURCE_MEM;
                        }
                        bus->resource[i+1] = res;
                }
        } else {
                /* This is a subordinate bridge */
                pci_read_bridge_bases(bus);

                for (i = 0; i < 4; ++i) {
                        if ((res = bus->resource[i]) == NULL)
                                continue;
                        if (!res->flags || bus->self->transparent)
                                continue;
                        if (io_offset && (res->flags & IORESOURCE_IO)) {
                                res->start += io_offset;
                                res->end += io_offset;
                        } else if (hose->pci_mem_offset
                                   && (res->flags & IORESOURCE_MEM)) {
                                res->start += hose->pci_mem_offset;
                                res->end += hose->pci_mem_offset;
                        }
                }
        }

        /* Platform specific bus fixups */
        if (ppc_md.pcibios_fixup_bus)
                ppc_md.pcibios_fixup_bus(bus);

        /* Read default IRQs and fixup if necessary */
        list_for_each_entry(dev, &bus->devices, bus_list) {
                pci_read_irq_line(dev);
                if (ppc_md.pci_irq_fixup)
                        ppc_md.pci_irq_fixup(dev);
        }
}

/* the next one is stolen from the alpha port... */
void __init
pcibios_update_irq(struct pci_dev *dev, int irq)
{
        pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
        /* XXX FIXME - update OF device tree node interrupt property */
}

int pcibios_enable_device(struct pci_dev *dev, int mask)
{
        u16 cmd, old_cmd;
        int idx;
        struct resource *r;

        if (ppc_md.pcibios_enable_device_hook)
                if (ppc_md.pcibios_enable_device_hook(dev, 0))
                        return -EINVAL;
                
        pci_read_config_word(dev, PCI_COMMAND, &cmd);
        old_cmd = cmd;
        for (idx=0; idx<6; idx++) {
                r = &dev->resource[idx];
                if (r->flags & IORESOURCE_UNSET) {
                        printk(KERN_ERR "PCI: Device %s not available because of resource collisions\n", pci_name(dev));
                        return -EINVAL;
                }
                if (r->flags & IORESOURCE_IO)
                        cmd |= PCI_COMMAND_IO;
                if (r->flags & IORESOURCE_MEM)
                        cmd |= PCI_COMMAND_MEMORY;
        }
        if (cmd != old_cmd) {
                printk("PCI: Enabling device %s (%04x -> %04x)\n",
                       pci_name(dev), old_cmd, cmd);
                pci_write_config_word(dev, PCI_COMMAND, cmd);
        }
        return 0;
}

static struct pci_controller*
pci_bus_to_hose(int bus)
{
        struct pci_controller *hose, *tmp;

        list_for_each_entry_safe(hose, tmp, &hose_list, list_node)
                if (bus >= hose->first_busno && bus <= hose->last_busno)
                        return hose;
        return NULL;
}

/* Provide information on locations of various I/O regions in physical
 * memory.  Do this on a per-card basis so that we choose the right
 * root bridge.
 * Note that the returned IO or memory base is a physical address
 */

long sys_pciconfig_iobase(long which, unsigned long bus, unsigned long devfn)
{
        struct pci_controller* hose;
        long result = -EOPNOTSUPP;

        /* Argh ! Please forgive me for that hack, but that's the
         * simplest way to get existing XFree to not lockup on some
         * G5 machines... So when something asks for bus 0 io base
         * (bus 0 is HT root), we return the AGP one instead.
         */
#ifdef CONFIG_PPC_PMAC
        if (machine_is(powermac) && machine_is_compatible("MacRISC4"))
                if (bus == 0)
                        bus = 0xf0;
#endif /* CONFIG_PPC_PMAC */

        hose = pci_bus_to_hose(bus);
        if (!hose)
                return -ENODEV;

        switch (which) {
        case IOBASE_BRIDGE_NUMBER:
                return (long)hose->first_busno;
        case IOBASE_MEMORY:
                return (long)hose->pci_mem_offset;
        case IOBASE_IO:
                return (long)hose->io_base_phys;
        case IOBASE_ISA_IO:
                return (long)isa_io_base;
        case IOBASE_ISA_MEM:
                return (long)isa_mem_base;
        }

        return result;
}

unsigned long pci_address_to_pio(phys_addr_t address)
{
        struct pci_controller *hose, *tmp;

        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
                unsigned int size = hose->io_resource.end -
                        hose->io_resource.start + 1;
                if (address >= hose->io_base_phys &&
                    address < (hose->io_base_phys + size)) {
                        unsigned long base =
                                (unsigned long)hose->io_base_virt - _IO_BASE;
                        return base + (address - hose->io_base_phys);
                }
        }
        return (unsigned int)-1;
}
EXPORT_SYMBOL(pci_address_to_pio);

/*
 * Null PCI config access functions, for the case when we can't
 * find a hose.
 */
#define NULL_PCI_OP(rw, size, type)                                     \
static int                                                              \
null_##rw##_config_##size(struct pci_dev *dev, int offset, type val)    \
{                                                                       \
        return PCIBIOS_DEVICE_NOT_FOUND;                                \
}

static int
null_read_config(struct pci_bus *bus, unsigned int devfn, int offset,
                 int len, u32 *val)
{
        return PCIBIOS_DEVICE_NOT_FOUND;
}

static int
null_write_config(struct pci_bus *bus, unsigned int devfn, int offset,
                  int len, u32 val)
{
        return PCIBIOS_DEVICE_NOT_FOUND;
}

static struct pci_ops null_pci_ops =
{
        .read = null_read_config,
        .write = null_write_config,
};

/*
 * These functions are used early on before PCI scanning is done
 * and all of the pci_dev and pci_bus structures have been created.
 */
static struct pci_bus *
fake_pci_bus(struct pci_controller *hose, int busnr)
{
        static struct pci_bus bus;

        if (hose == 0) {
                hose = pci_bus_to_hose(busnr);
                if (hose == 0)
                        printk(KERN_ERR "Can't find hose for PCI bus %d!\n", busnr);
        }
        bus.number = busnr;
        bus.sysdata = hose;
        bus.ops = hose? hose->ops: &null_pci_ops;
        return &bus;
}

#define EARLY_PCI_OP(rw, size, type)                                    \
int early_##rw##_config_##size(struct pci_controller *hose, int bus,    \
                               int devfn, int offset, type value)       \
{                                                                       \
        return pci_bus_##rw##_config_##size(fake_pci_bus(hose, bus),    \
                                            devfn, offset, value);      \
}

EARLY_PCI_OP(read, byte, u8 *)
EARLY_PCI_OP(read, word, u16 *)
EARLY_PCI_OP(read, dword, u32 *)
EARLY_PCI_OP(write, byte, u8)
EARLY_PCI_OP(write, word, u16)
EARLY_PCI_OP(write, dword, u32)

extern int pci_bus_find_capability (struct pci_bus *bus, unsigned int devfn, int cap);
int early_find_capability(struct pci_controller *hose, int bus, int devfn,
                          int cap)
{
        return pci_bus_find_capability(fake_pci_bus(hose, bus), devfn, cap);
}