mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race

[linux/fpc-iii.git] / arch / microblaze / pci / pci-common.c

/*
 * Contains common pci routines for ALL ppc platform
 * (based on pci_32.c and pci_64.c)
 *
 * Port for PPC64 David Engebretsen, IBM Corp.
 * Contains common pci routines for ppc64 platform, pSeries and iSeries brands.
 *
 * Copyright (C) 2003 Anton Blanchard <anton@au.ibm.com>, IBM
 *   Rework, based on alpha PCI code.
 *
 * Common pmac/prep/chrp pci routines. -- Cort
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/shmem_fs.h>
#include <linux/list.h>
#include <linux/syscalls.h>
#include <linux/irq.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/export.h>

#include <asm/processor.h>
#include <linux/io.h>
#include <asm/pci-bridge.h>
#include <asm/byteorder.h>

static DEFINE_SPINLOCK(hose_spinlock);
LIST_HEAD(hose_list);

/* XXX kill that some day ... */
static int global_phb_number;           /* Global phb counter */

/* ISA Memory physical address */
resource_size_t isa_mem_base;

unsigned long isa_io_base;
EXPORT_SYMBOL(isa_io_base);

static int pci_bus_count;

struct pci_controller *pcibios_alloc_controller(struct device_node *dev)
{
        struct pci_controller *phb;

        phb = zalloc_maybe_bootmem(sizeof(struct pci_controller), GFP_KERNEL);
        if (!phb)
                return NULL;
        spin_lock(&hose_spinlock);
        phb->global_number = global_phb_number++;
        list_add_tail(&phb->list_node, &hose_list);
        spin_unlock(&hose_spinlock);
        phb->dn = dev;
        phb->is_dynamic = mem_init_done;
        return phb;
}

void pcibios_free_controller(struct pci_controller *phb)
{
        spin_lock(&hose_spinlock);
        list_del(&phb->list_node);
        spin_unlock(&hose_spinlock);

        if (phb->is_dynamic)
                kfree(phb);
}

static resource_size_t pcibios_io_size(const struct pci_controller *hose)
{
        return resource_size(&hose->io_resource);
}

int pcibios_vaddr_is_ioport(void __iomem *address)
{
        int ret = 0;
        struct pci_controller *hose;
        resource_size_t size;

        spin_lock(&hose_spinlock);
        list_for_each_entry(hose, &hose_list, list_node) {
                size = pcibios_io_size(hose);
                if (address >= hose->io_base_virt &&
                    address < (hose->io_base_virt + size)) {
                        ret = 1;
                        break;
                }
        }
        spin_unlock(&hose_spinlock);
        return ret;
}

unsigned long pci_address_to_pio(phys_addr_t address)
{
        struct pci_controller *hose;
        resource_size_t size;
        unsigned long ret = ~0;

        spin_lock(&hose_spinlock);
        list_for_each_entry(hose, &hose_list, list_node) {
                size = pcibios_io_size(hose);
                if (address >= hose->io_base_phys &&
                    address < (hose->io_base_phys + size)) {
                        unsigned long base =
                                (unsigned long)hose->io_base_virt - _IO_BASE;
                        ret = base + (address - hose->io_base_phys);
                        break;
                }
        }
        spin_unlock(&hose_spinlock);

        return ret;
}
EXPORT_SYMBOL_GPL(pci_address_to_pio);

/* This routine is meant to be used early during boot, when the
 * PCI bus numbers have not yet been assigned, and you need to
 * issue PCI config cycles to an OF device.
 * It could also be used to "fix" RTAS config cycles if you want
 * to set pci_assign_all_buses to 1 and still use RTAS for PCI
 * config cycles.
 */
struct pci_controller *pci_find_hose_for_OF_device(struct device_node *node)
{
        while (node) {
                struct pci_controller *hose, *tmp;
                list_for_each_entry_safe(hose, tmp, &hose_list, list_node)
                        if (hose->dn == node)
                                return hose;
                node = node->parent;
        }
        return NULL;
}

void pcibios_set_master(struct pci_dev *dev)
{
        /* No special bus mastering setup handling */
}

/*
 * Platform support for /proc/bus/pci/X/Y mmap()s,
 * modelled on the sparc64 implementation by Dave Miller.
 *  -- paulus.
 */

/*
 * Adjust vm_pgoff of VMA such that it is the physical page offset
 * corresponding to the 32-bit pci bus offset for DEV requested by the user.
 *
 * Basically, the user finds the base address for his device which he wishes
 * to mmap.  They read the 32-bit value from the config space base register,
 * add whatever PAGE_SIZE multiple offset they wish, and feed this into the
 * offset parameter of mmap on /proc/bus/pci/XXX for that device.
 *
 * Returns negative error code on failure, zero on success.
 */
static struct resource *__pci_mmap_make_offset(struct pci_dev *dev,
                                               resource_size_t *offset,
                                               enum pci_mmap_state mmap_state)
{
        struct pci_controller *hose = pci_bus_to_host(dev->bus);
        unsigned long io_offset = 0;
        int i, res_bit;

        if (!hose)
                return NULL;            /* should never happen */

        /* If memory, add on the PCI bridge address offset */
        if (mmap_state == pci_mmap_mem) {
#if 0 /* See comment in pci_resource_to_user() for why this is disabled */
                *offset += hose->pci_mem_offset;
#endif
                res_bit = IORESOURCE_MEM;
        } else {
                io_offset = (unsigned long)hose->io_base_virt - _IO_BASE;
                *offset += io_offset;
                res_bit = IORESOURCE_IO;
        }

        /*
         * Check that the offset requested corresponds to one of the
         * resources of the device.
         */
        for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
                struct resource *rp = &dev->resource[i];
                int flags = rp->flags;

                /* treat ROM as memory (should be already) */
                if (i == PCI_ROM_RESOURCE)
                        flags |= IORESOURCE_MEM;

                /* Active and same type? */
                if ((flags & res_bit) == 0)
                        continue;

                /* In the range of this resource? */
                if (*offset < (rp->start & PAGE_MASK) || *offset > rp->end)
                        continue;

                /* found it! construct the final physical address */
                if (mmap_state == pci_mmap_io)
                        *offset += hose->io_base_phys - io_offset;
                return rp;
        }

        return NULL;
}

/*
 * This one is used by /dev/mem and fbdev who have no clue about the
 * PCI device, it tries to find the PCI device first and calls the
 * above routine
 */
pgprot_t pci_phys_mem_access_prot(struct file *file,
                                  unsigned long pfn,
                                  unsigned long size,
                                  pgprot_t prot)
{
        struct pci_dev *pdev = NULL;
        struct resource *found = NULL;
        resource_size_t offset = ((resource_size_t)pfn) << PAGE_SHIFT;
        int i;

        if (page_is_ram(pfn))
                return prot;

        prot = pgprot_noncached(prot);
        for_each_pci_dev(pdev) {
                for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
                        struct resource *rp = &pdev->resource[i];
                        int flags = rp->flags;

                        /* Active and same type? */
                        if ((flags & IORESOURCE_MEM) == 0)
                                continue;
                        /* In the range of this resource? */
                        if (offset < (rp->start & PAGE_MASK) ||
                            offset > rp->end)
                                continue;
                        found = rp;
                        break;
                }
                if (found)
                        break;
        }
        if (found) {
                if (found->flags & IORESOURCE_PREFETCH)
                        prot = pgprot_noncached_wc(prot);
                pci_dev_put(pdev);
        }

        pr_debug("PCI: Non-PCI map for %llx, prot: %lx\n",
                 (unsigned long long)offset, pgprot_val(prot));

        return prot;
}

/*
 * Perform the actual remap of the pages for a PCI device mapping, as
 * appropriate for this architecture.  The region in the process to map
 * is described by vm_start and vm_end members of VMA, the base physical
 * address is found in vm_pgoff.
 * The pci device structure is provided so that architectures may make mapping
 * decisions on a per-device or per-bus basis.
 *
 * Returns a negative error code on failure, zero on success.
 */
int pci_mmap_page_range(struct pci_dev *dev, int bar, struct vm_area_struct *vma,
                        enum pci_mmap_state mmap_state, int write_combine)
{
        resource_size_t offset =
                ((resource_size_t)vma->vm_pgoff) << PAGE_SHIFT;
        struct resource *rp;
        int ret;

        rp = __pci_mmap_make_offset(dev, &offset, mmap_state);
        if (rp == NULL)
                return -EINVAL;

        vma->vm_pgoff = offset >> PAGE_SHIFT;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        ret = remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
                               vma->vm_end - vma->vm_start, vma->vm_page_prot);

        return ret;
}

/* This provides legacy IO read access on a bus */
int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val, size_t size)
{
        unsigned long offset;
        struct pci_controller *hose = pci_bus_to_host(bus);
        struct resource *rp = &hose->io_resource;
        void __iomem *addr;

        /* Check if port can be supported by that bus. We only check
         * the ranges of the PHB though, not the bus itself as the rules
         * for forwarding legacy cycles down bridges are not our problem
         * here. So if the host bridge supports it, we do it.
         */
        offset = (unsigned long)hose->io_base_virt - _IO_BASE;
        offset += port;

        if (!(rp->flags & IORESOURCE_IO))
                return -ENXIO;
        if (offset < rp->start || (offset + size) > rp->end)
                return -ENXIO;
        addr = hose->io_base_virt + port;

        switch (size) {
        case 1:
                *((u8 *)val) = in_8(addr);
                return 1;
        case 2:
                if (port & 1)
                        return -EINVAL;
                *((u16 *)val) = in_le16(addr);
                return 2;
        case 4:
                if (port & 3)
                        return -EINVAL;
                *((u32 *)val) = in_le32(addr);
                return 4;
        }
        return -EINVAL;
}

/* This provides legacy IO write access on a bus */
int pci_legacy_write(struct pci_bus *bus, loff_t port, u32 val, size_t size)
{
        unsigned long offset;
        struct pci_controller *hose = pci_bus_to_host(bus);
        struct resource *rp = &hose->io_resource;
        void __iomem *addr;

        /* Check if port can be supported by that bus. We only check
         * the ranges of the PHB though, not the bus itself as the rules
         * for forwarding legacy cycles down bridges are not our problem
         * here. So if the host bridge supports it, we do it.
         */
        offset = (unsigned long)hose->io_base_virt - _IO_BASE;
        offset += port;

        if (!(rp->flags & IORESOURCE_IO))
                return -ENXIO;
        if (offset < rp->start || (offset + size) > rp->end)
                return -ENXIO;
        addr = hose->io_base_virt + port;

        /* WARNING: The generic code is idiotic. It gets passed a pointer
         * to what can be a 1, 2 or 4 byte quantity and always reads that
         * as a u32, which means that we have to correct the location of
         * the data read within those 32 bits for size 1 and 2
         */
        switch (size) {
        case 1:
                out_8(addr, val >> 24);
                return 1;
        case 2:
                if (port & 1)
                        return -EINVAL;
                out_le16(addr, val >> 16);
                return 2;
        case 4:
                if (port & 3)
                        return -EINVAL;
                out_le32(addr, val);
                return 4;
        }
        return -EINVAL;
}

/* This provides legacy IO or memory mmap access on a bus */
int pci_mmap_legacy_page_range(struct pci_bus *bus,
                               struct vm_area_struct *vma,
                               enum pci_mmap_state mmap_state)
{
        struct pci_controller *hose = pci_bus_to_host(bus);
        resource_size_t offset =
                ((resource_size_t)vma->vm_pgoff) << PAGE_SHIFT;
        resource_size_t size = vma->vm_end - vma->vm_start;
        struct resource *rp;

        pr_debug("pci_mmap_legacy_page_range(%04x:%02x, %s @%llx..%llx)\n",
                 pci_domain_nr(bus), bus->number,
                 mmap_state == pci_mmap_mem ? "MEM" : "IO",
                 (unsigned long long)offset,
                 (unsigned long long)(offset + size - 1));

        if (mmap_state == pci_mmap_mem) {
                /* Hack alert !
                 *
                 * Because X is lame and can fail starting if it gets an error
                 * trying to mmap legacy_mem (instead of just moving on without
                 * legacy memory access) we fake it here by giving it anonymous
                 * memory, effectively behaving just like /dev/zero
                 */
                if ((offset + size) > hose->isa_mem_size) {
#ifdef CONFIG_MMU
                        pr_debug("Process %s (pid:%d) mapped non-existing PCI",
                                current->comm, current->pid);
                        pr_debug("legacy memory for 0%04x:%02x\n",
                                pci_domain_nr(bus), bus->number);
#endif
                        if (vma->vm_flags & VM_SHARED)
                                return shmem_zero_setup(vma);
                        return 0;
                }
                offset += hose->isa_mem_phys;
        } else {
                unsigned long io_offset = (unsigned long)hose->io_base_virt -
                                                                _IO_BASE;
                unsigned long roffset = offset + io_offset;
                rp = &hose->io_resource;
                if (!(rp->flags & IORESOURCE_IO))
                        return -ENXIO;
                if (roffset < rp->start || (roffset + size) > rp->end)
                        return -ENXIO;
                offset += hose->io_base_phys;
        }
        pr_debug(" -> mapping phys %llx\n", (unsigned long long)offset);

        vma->vm_pgoff = offset >> PAGE_SHIFT;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
        return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
                               vma->vm_end - vma->vm_start,
                               vma->vm_page_prot);
}

void pci_resource_to_user(const struct pci_dev *dev, int bar,
                          const struct resource *rsrc,
                          resource_size_t *start, resource_size_t *end)
{
        struct pci_bus_region region;

        if (rsrc->flags & IORESOURCE_IO) {
                pcibios_resource_to_bus(dev->bus, &region,
                                        (struct resource *) rsrc);
                *start = region.start;
                *end = region.end;
                return;
        }

        /* We pass a CPU physical address to userland for MMIO instead of a
         * BAR value because X is lame and expects to be able to use that
         * to pass to /dev/mem!
         *
         * That means we may have 64-bit values where some apps only expect
         * 32 (like X itself since it thinks only Sparc has 64-bit MMIO).
         */
        *start = rsrc->start;
        *end = rsrc->end;
}

/**
 * pci_process_bridge_OF_ranges - Parse PCI bridge resources from device tree
 * @hose: newly allocated pci_controller to be setup
 * @dev: device node of the host bridge
 * @primary: set if primary bus (32 bits only, soon to be deprecated)
 *
 * This function will parse the "ranges" property of a PCI host bridge device
 * node and setup the resource mapping of a pci controller based on its
 * content.
 *
 * Life would be boring if it wasn't for a few issues that we have to deal
 * with here:
 *
 *   - We can only cope with one IO space range and up to 3 Memory space
 *     ranges. However, some machines (thanks Apple !) tend to split their
 *     space into lots of small contiguous ranges. So we have to coalesce.
 *
 *   - We can only cope with all memory ranges having the same offset
 *     between CPU addresses and PCI addresses. Unfortunately, some bridges
 *     are setup for a large 1:1 mapping along with a small "window" which
 *     maps PCI address 0 to some arbitrary high address of the CPU space in
 *     order to give access to the ISA memory hole.
 *     The way out of here that I've chosen for now is to always set the
 *     offset based on the first resource found, then override it if we
 *     have a different offset and the previous was set by an ISA hole.
 *
 *   - Some busses have IO space not starting at 0, which causes trouble with
 *     the way we do our IO resource renumbering. The code somewhat deals with
 *     it for 64 bits but I would expect problems on 32 bits.
 *
 *   - Some 32 bits platforms such as 4xx can have physical space larger than
 *     32 bits so we need to use 64 bits values for the parsing
 */
void pci_process_bridge_OF_ranges(struct pci_controller *hose,
                                  struct device_node *dev, int primary)
{
        int memno = 0, isa_hole = -1;
        unsigned long long isa_mb = 0;
        struct resource *res;
        struct of_pci_range range;
        struct of_pci_range_parser parser;

        pr_info("PCI host bridge %pOF %s ranges:\n",
               dev, primary ? "(primary)" : "");

        /* Check for ranges property */
        if (of_pci_range_parser_init(&parser, dev))
                return;

        pr_debug("Parsing ranges property...\n");
        for_each_of_pci_range(&parser, &range) {
                /* Read next ranges element */
                pr_debug("pci_space: 0x%08x pci_addr:0x%016llx ",
                                range.pci_space, range.pci_addr);
                pr_debug("cpu_addr:0x%016llx size:0x%016llx\n",
                                        range.cpu_addr, range.size);

                /* If we failed translation or got a zero-sized region
                 * (some FW try to feed us with non sensical zero sized regions
                 * such as power3 which look like some kind of attempt
                 * at exposing the VGA memory hole)
                 */
                if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
                        continue;

                /* Act based on address space type */
                res = NULL;
                switch (range.flags & IORESOURCE_TYPE_BITS) {
                case IORESOURCE_IO:
                        pr_info("  IO 0x%016llx..0x%016llx -> 0x%016llx\n",
                                range.cpu_addr, range.cpu_addr + range.size - 1,
                                range.pci_addr);

                        /* We support only one IO range */
                        if (hose->pci_io_size) {
                                pr_info(" \\--> Skipped (too many) !\n");
                                continue;
                        }
                        /* On 32 bits, limit I/O space to 16MB */
                        if (range.size > 0x01000000)
                                range.size = 0x01000000;

                        /* 32 bits needs to map IOs here */
                        hose->io_base_virt = ioremap(range.cpu_addr,
                                                range.size);

                        /* Expect trouble if pci_addr is not 0 */
                        if (primary)
                                isa_io_base =
                                        (unsigned long)hose->io_base_virt;
                        /* pci_io_size and io_base_phys always represent IO
                         * space starting at 0 so we factor in pci_addr
                         */
                        hose->pci_io_size = range.pci_addr + range.size;
                        hose->io_base_phys = range.cpu_addr - range.pci_addr;

                        /* Build resource */
                        res = &hose->io_resource;
                        range.cpu_addr = range.pci_addr;

                        break;
                case IORESOURCE_MEM:
                        pr_info(" MEM 0x%016llx..0x%016llx -> 0x%016llx %s\n",
                                range.cpu_addr, range.cpu_addr + range.size - 1,
                                range.pci_addr,
                                (range.pci_space & 0x40000000) ?
                                "Prefetch" : "");

                        /* We support only 3 memory ranges */
                        if (memno >= 3) {
                                pr_info(" \\--> Skipped (too many) !\n");
                                continue;
                        }
                        /* Handles ISA memory hole space here */
                        if (range.pci_addr == 0) {
                                isa_mb = range.cpu_addr;
                                isa_hole = memno;
                                if (primary || isa_mem_base == 0)
                                        isa_mem_base = range.cpu_addr;
                                hose->isa_mem_phys = range.cpu_addr;
                                hose->isa_mem_size = range.size;
                        }

                        /* We get the PCI/Mem offset from the first range or
                         * the, current one if the offset came from an ISA
                         * hole. If they don't match, bugger.
                         */
                        if (memno == 0 ||
                            (isa_hole >= 0 && range.pci_addr != 0 &&
                             hose->pci_mem_offset == isa_mb))
                                hose->pci_mem_offset = range.cpu_addr -
                                                        range.pci_addr;
                        else if (range.pci_addr != 0 &&
                                 hose->pci_mem_offset != range.cpu_addr -
                                                        range.pci_addr) {
                                pr_info(" \\--> Skipped (offset mismatch) !\n");
                                continue;
                        }

                        /* Build resource */
                        res = &hose->mem_resources[memno++];
                        break;
                }
                if (res != NULL) {
                        res->name = dev->full_name;
                        res->flags = range.flags;
                        res->start = range.cpu_addr;
                        res->end = range.cpu_addr + range.size - 1;
                        res->parent = res->child = res->sibling = NULL;
                }
        }

        /* If there's an ISA hole and the pci_mem_offset is -not- matching
         * the ISA hole offset, then we need to remove the ISA hole from
         * the resource list for that brige
         */
        if (isa_hole >= 0 && hose->pci_mem_offset != isa_mb) {
                unsigned int next = isa_hole + 1;
                pr_info(" Removing ISA hole at 0x%016llx\n", isa_mb);
                if (next < memno)
                        memmove(&hose->mem_resources[isa_hole],
                                &hose->mem_resources[next],
                                sizeof(struct resource) * (memno - next));
                hose->mem_resources[--memno].flags = 0;
        }
}

/* Display the domain number in /proc */
int pci_proc_domain(struct pci_bus *bus)
{
        return pci_domain_nr(bus);
}

/* This header fixup will do the resource fixup for all devices as they are
 * probed, but not for bridge ranges
 */
static void pcibios_fixup_resources(struct pci_dev *dev)
{
        struct pci_controller *hose = pci_bus_to_host(dev->bus);
        int i;

        if (!hose) {
                pr_err("No host bridge 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->start == 0) {
                        pr_debug("PCI:%s Resource %d %016llx-%016llx [%x]",
                                 pci_name(dev), i,
                                 (unsigned long long)res->start,
                                 (unsigned long long)res->end,
                                 (unsigned int)res->flags);
                        pr_debug("is unassigned\n");
                        res->end -= res->start;
                        res->start = 0;
                        res->flags |= IORESOURCE_UNSET;
                        continue;
                }

                pr_debug("PCI:%s Resource %d %016llx-%016llx [%x]\n",
                         pci_name(dev), i,
                         (unsigned long long)res->start,
                         (unsigned long long)res->end,
                         (unsigned int)res->flags);
        }
}
DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pcibios_fixup_resources);

/*
 * 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..
 */
int pcibios_add_device(struct pci_dev *dev)
{
        dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);

        return 0;
}
EXPORT_SYMBOL(pcibios_add_device);

/*
 * 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;
                pr_debug("PCI: Reparented %s [%llx..%llx] under %s\n",
                         p->name,
                         (unsigned long long)p->start,
                         (unsigned long long)p->end, res->name);
        }
        return 0;
}

/*
 *  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 pcibios_allocate_bus_resources(struct pci_bus *bus)
{
        struct pci_bus *b;
        int i;
        struct resource *res, *pr;

        pr_debug("PCI: Allocating bus resources for %04x:%02x...\n",
                 pci_domain_nr(bus), bus->number);

        pci_bus_for_each_resource(bus, res, i) {
                if (!res || !res->flags
                    || res->start > res->end || res->parent)
                        continue;
                if (bus->parent == NULL)
                        pr = (res->flags & IORESOURCE_IO) ?
                                &ioport_resource : &iomem_resource;
                else {
                        /* Don't bother with non-root busses when
                         * re-assigning all resources. We clear the
                         * resource flags as if they were colliding
                         * and as such ensure proper re-allocation
                         * later.
                         */
                        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;
                        }
                }

                pr_debug("PCI: %s (bus %d) bridge rsrc %d: %016llx-%016llx ",
                         bus->self ? pci_name(bus->self) : "PHB",
                         bus->number, i,
                         (unsigned long long)res->start,
                         (unsigned long long)res->end);
                pr_debug("[0x%x], parent %p (%s)\n",
                         (unsigned int)res->flags,
                         pr, (pr && pr->name) ? pr->name : "nil");

                if (pr && !(pr->flags & IORESOURCE_UNSET)) {
                        struct pci_dev *dev = bus->self;

                        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;

                        if (dev && i < PCI_BRIDGE_RESOURCE_NUM &&
                            pci_claim_bridge_resource(dev,
                                                 i + PCI_BRIDGE_RESOURCES) == 0)
                                continue;

                }
                pr_warn("PCI: Cannot allocate resource region ");
                pr_cont("%d of PCI bridge %d, will remap\n", i, bus->number);
                res->start = res->end = 0;
                res->flags = 0;
        }

        list_for_each_entry(b, &bus->children, node)
                pcibios_allocate_bus_resources(b);
}

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

        pr_debug("PCI: Allocating %s: Resource %d: %016llx..%016llx [%x]\n",
                 pci_name(dev), idx,
                 (unsigned long long)r->start,
                 (unsigned long long)r->end,
                 (unsigned int)r->flags);

        pr = pci_find_parent_resource(dev, r);
        if (!pr || (pr->flags & IORESOURCE_UNSET) ||
            request_resource(pr, r) < 0) {
                pr_warn("PCI: Cannot allocate resource region %d ", idx);
                pr_cont("of device %s, will remap\n", pci_name(dev));
                if (pr)
                        pr_debug("PCI:  parent is %p: %016llx-%016llx [%x]\n",
                                 pr,
                                 (unsigned long long)pr->start,
                                 (unsigned long long)pr->end,
                                 (unsigned int)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 <= PCI_ROM_RESOURCE; idx++) {
                        r = &dev->resource[idx];
                        if (r->parent)          /* Already allocated */
                                continue;
                        if (!r->flags || (r->flags & IORESOURCE_UNSET))
                                continue;       /* Not assigned at all */
                        /* We only allocate ROMs on pass 1 just in case they
                         * have been screwed up by firmware
                         */
                        if (idx == PCI_ROM_RESOURCE)
                                disabled = 1;
                        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) {
                        /* Turn the ROM off, leave the resource region,
                         * but keep it unregistered.
                         */
                        u32 reg;
                        pci_read_config_dword(dev, dev->rom_base_reg, &reg);
                        if (reg & PCI_ROM_ADDRESS_ENABLE) {
                                pr_debug("PCI: Switching off ROM of %s\n",
                                         pci_name(dev));
                                r->flags &= ~IORESOURCE_ROM_ENABLE;
                                pci_write_config_dword(dev, dev->rom_base_reg,
                                                reg & ~PCI_ROM_ADDRESS_ENABLE);
                        }
                }
        }
}

static void __init pcibios_reserve_legacy_regions(struct pci_bus *bus)
{
        struct pci_controller *hose = pci_bus_to_host(bus);
        resource_size_t offset;
        struct resource *res, *pres;
        int i;

        pr_debug("Reserving legacy ranges for domain %04x\n",
                                                        pci_domain_nr(bus));

        /* Check for IO */
        if (!(hose->io_resource.flags & IORESOURCE_IO))
                goto no_io;
        offset = (unsigned long)hose->io_base_virt - _IO_BASE;
        res = kzalloc(sizeof(struct resource), GFP_KERNEL);
        BUG_ON(res == NULL);
        res->name = "Legacy IO";
        res->flags = IORESOURCE_IO;
        res->start = offset;
        res->end = (offset + 0xfff) & 0xfffffffful;
        pr_debug("Candidate legacy IO: %pR\n", res);
        if (request_resource(&hose->io_resource, res)) {
                pr_debug("PCI %04x:%02x Cannot reserve Legacy IO %pR\n",
                       pci_domain_nr(bus), bus->number, res);
                kfree(res);
        }

 no_io:
        /* Check for memory */
        offset = hose->pci_mem_offset;
        pr_debug("hose mem offset: %016llx\n", (unsigned long long)offset);
        for (i = 0; i < 3; i++) {
                pres = &hose->mem_resources[i];
                if (!(pres->flags & IORESOURCE_MEM))
                        continue;
                pr_debug("hose mem res: %pR\n", pres);
                if ((pres->start - offset) <= 0xa0000 &&
                    (pres->end - offset) >= 0xbffff)
                        break;
        }
        if (i >= 3)
                return;
        res = kzalloc(sizeof(struct resource), GFP_KERNEL);
        BUG_ON(res == NULL);
        res->name = "Legacy VGA memory";
        res->flags = IORESOURCE_MEM;
        res->start = 0xa0000 + offset;
        res->end = 0xbffff + offset;
        pr_debug("Candidate VGA memory: %pR\n", res);
        if (request_resource(pres, res)) {
                pr_debug("PCI %04x:%02x Cannot reserve VGA memory %pR\n",
                       pci_domain_nr(bus), bus->number, res);
                kfree(res);
        }
}

void __init pcibios_resource_survey(void)
{
        struct pci_bus *b;

        /* Allocate and assign resources. If we re-assign everything, then
         * we skip the allocate phase
         */
        list_for_each_entry(b, &pci_root_buses, node)
                pcibios_allocate_bus_resources(b);

        pcibios_allocate_resources(0);
        pcibios_allocate_resources(1);

        /* Before we start assigning unassigned resource, we try to reserve
         * the low IO area and the VGA memory area if they intersect the
         * bus available resources to avoid allocating things on top of them
         */
        list_for_each_entry(b, &pci_root_buses, node)
                pcibios_reserve_legacy_regions(b);

        /* Now proceed to assigning things that were left unassigned */
        pr_debug("PCI: Assigning unassigned resources...\n");
        pci_assign_unassigned_resources();
}

/* This is used by the PCI hotplug driver to allocate resource
 * of newly plugged busses. We can try to consolidate with the
 * rest of the code later, for now, keep it as-is as our main
 * resource allocation function doesn't deal with sub-trees yet.
 */
void pcibios_claim_one_bus(struct pci_bus *bus)
{
        struct pci_dev *dev;
        struct pci_bus *child_bus;

        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];

                        if (r->parent || !r->start || !r->flags)
                                continue;

                        pr_debug("PCI: Claiming %s: ", pci_name(dev));
                        pr_debug("Resource %d: %016llx..%016llx [%x]\n",
                                 i, (unsigned long long)r->start,
                                 (unsigned long long)r->end,
                                 (unsigned int)r->flags);

                        if (pci_claim_resource(dev, i) == 0)
                                continue;

                        pci_claim_bridge_resource(dev, i);
                }
        }

        list_for_each_entry(child_bus, &bus->children, node)
                pcibios_claim_one_bus(child_bus);
}
EXPORT_SYMBOL_GPL(pcibios_claim_one_bus);


/* pcibios_finish_adding_to_bus
 *
 * This is to be called by the hotplug code after devices have been
 * added to a bus, this include calling it for a PHB that is just
 * being added
 */
void pcibios_finish_adding_to_bus(struct pci_bus *bus)
{
        pr_debug("PCI: Finishing adding to hotplug bus %04x:%02x\n",
                 pci_domain_nr(bus), bus->number);

        /* Allocate bus and devices resources */
        pcibios_allocate_bus_resources(bus);
        pcibios_claim_one_bus(bus);

        /* Add new devices to global lists.  Register in proc, sysfs. */
        pci_bus_add_devices(bus);

        /* Fixup EEH */
        /* eeh_add_device_tree_late(bus); */
}
EXPORT_SYMBOL_GPL(pcibios_finish_adding_to_bus);

static void pcibios_setup_phb_resources(struct pci_controller *hose,
                                        struct list_head *resources)
{
        unsigned long io_offset;
        struct resource *res;
        int i;

        /* Hookup PHB IO resource */
        res = &hose->io_resource;

        /* Fixup IO space offset */
        io_offset = (unsigned long)hose->io_base_virt - isa_io_base;
        res->start = (res->start + io_offset) & 0xffffffffu;
        res->end = (res->end + io_offset) & 0xffffffffu;

        if (!res->flags) {
                pr_warn("PCI: I/O resource not set for host ");
                pr_cont("bridge %pOF (domain %d)\n",
                        hose->dn, hose->global_number);
                /* Workaround for lack of IO resource only on 32-bit */
                res->start = (unsigned long)hose->io_base_virt - isa_io_base;
                res->end = res->start + IO_SPACE_LIMIT;
                res->flags = IORESOURCE_IO;
        }
        pci_add_resource_offset(resources, res,
                (__force resource_size_t)(hose->io_base_virt - _IO_BASE));

        pr_debug("PCI: PHB IO resource    = %016llx-%016llx [%lx]\n",
                 (unsigned long long)res->start,
                 (unsigned long long)res->end,
                 (unsigned long)res->flags);

        /* Hookup PHB Memory resources */
        for (i = 0; i < 3; ++i) {
                res = &hose->mem_resources[i];
                if (!res->flags) {
                        if (i > 0)
                                continue;
                        pr_err("PCI: Memory resource 0 not set for ");
                        pr_cont("host bridge %pOF (domain %d)\n",
                                hose->dn, hose->global_number);

                        /* Workaround for lack of MEM resource only on 32-bit */
                        res->start = hose->pci_mem_offset;
                        res->end = (resource_size_t)-1LL;
                        res->flags = IORESOURCE_MEM;

                }
                pci_add_resource_offset(resources, res, hose->pci_mem_offset);

                pr_debug("PCI: PHB MEM resource %d = %016llx-%016llx [%lx]\n",
                        i, (unsigned long long)res->start,
                        (unsigned long long)res->end,
                        (unsigned long)res->flags);
        }

        pr_debug("PCI: PHB MEM offset     = %016llx\n",
                 (unsigned long long)hose->pci_mem_offset);
        pr_debug("PCI: PHB IO  offset     = %08lx\n",
                 (unsigned long)hose->io_base_virt - _IO_BASE);
}

static void pcibios_scan_phb(struct pci_controller *hose)
{
        LIST_HEAD(resources);
        struct pci_bus *bus;
        struct device_node *node = hose->dn;

        pr_debug("PCI: Scanning PHB %pOF\n", node);

        pcibios_setup_phb_resources(hose, &resources);

        bus = pci_scan_root_bus(hose->parent, hose->first_busno,
                                hose->ops, hose, &resources);
        if (bus == NULL) {
                pr_err("Failed to create bus for PCI domain %04x\n",
                       hose->global_number);
                pci_free_resource_list(&resources);
                return;
        }
        bus->busn_res.start = hose->first_busno;
        hose->bus = bus;

        hose->last_busno = bus->busn_res.end;
}

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

        pr_info("PCI: Probing PCI hardware\n");

        /* Scan all of the recorded PCI controllers.  */
        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
                hose->last_busno = 0xff;
                pcibios_scan_phb(hose);
                if (next_busno <= hose->last_busno)
                        next_busno = hose->last_busno + 1;
        }
        pci_bus_count = next_busno;

        /* Call common code to handle resource allocation */
        pcibios_resource_survey();
        list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {
                if (hose->bus)
                        pci_bus_add_devices(hose->bus);
        }

        return 0;
}

subsys_initcall(pcibios_init);

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;

        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;
}

/*
 * 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)
                pr_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)

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);
}