kolibrios/drivers/devman/pci/probe.c

#include <ddk.h>
#include <linux/errno.h>
#include <mutex.h>
#include <pci.h>
#include <syscall.h>

LIST_HEAD(pci_root_buses);

#define IO_SPACE_LIMIT 0xffff




#define LEGACY_IO_RESOURCE  (IORESOURCE_IO | IORESOURCE_PCI_FIXED)

#define CARDBUS_LATENCY_TIMER   176 /* secondary latency timer */
#define CARDBUS_RESERVE_BUSNR   3

static int pcibios_assign_all_busses(void)
{
    return 0;
};

/**
 * pci_ari_enabled - query ARI forwarding status
 * @bus: the PCI bus
 *
 * Returns 1 if ARI forwarding is enabled, or 0 if not enabled;
 */
static inline int pci_ari_enabled(struct pci_bus *bus)
{
    return bus->self && bus->self->ari_enabled;
}

/*
 * Translate the low bits of the PCI base
 * to the resource type
 */
static inline unsigned int pci_calc_resource_flags(unsigned int flags)
{
    if (flags & PCI_BASE_ADDRESS_SPACE_IO)
        return IORESOURCE_IO;

    if (flags & PCI_BASE_ADDRESS_MEM_PREFETCH)
        return IORESOURCE_MEM | IORESOURCE_PREFETCH;

    return IORESOURCE_MEM;
}

static u64 pci_size(u64 base, u64 maxbase, u64 mask)
{
    u64 size = mask & maxbase;  /* Find the significant bits */
    if (!size)
        return 0;

    /* Get the lowest of them to find the decode size, and
       from that the extent.  */
    size = (size & ~(size-1)) - 1;

    /* base == maxbase can be valid only if the BAR has
       already been programmed with all 1s.  */
    if (base == maxbase && ((base | size) & mask) != mask)
        return 0;

    return size;
}

static inline enum pci_bar_type decode_bar(struct resource *res, u32 bar)
{
    if ((bar & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
        res->flags = bar & ~PCI_BASE_ADDRESS_IO_MASK;
        return pci_bar_io;
    }

    res->flags = bar & ~PCI_BASE_ADDRESS_MEM_MASK;

    if (res->flags & PCI_BASE_ADDRESS_MEM_TYPE_64)
        return pci_bar_mem64;
    return pci_bar_mem32;
}



/**
 * pci_read_base - read a PCI BAR
 * @dev: the PCI device
 * @type: type of the BAR
 * @res: resource buffer to be filled in
 * @pos: BAR position in the config space
 *
 * Returns 1 if the BAR is 64-bit, or 0 if 32-bit.
 */
int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
            struct resource *res, unsigned int pos)
{
    u32 l, sz, mask;
    u16 orig_cmd;

    mask = type ? PCI_ROM_ADDRESS_MASK : ~0;

    if (!dev->mmio_always_on) {
        pci_read_config_word(dev, PCI_COMMAND, &orig_cmd);
        pci_write_config_word(dev, PCI_COMMAND,
            orig_cmd & ~(PCI_COMMAND_MEMORY | PCI_COMMAND_IO));
    }

    res->name = pci_name(dev);

    pci_read_config_dword(dev, pos, &l);
    pci_write_config_dword(dev, pos, l | mask);
    pci_read_config_dword(dev, pos, &sz);
    pci_write_config_dword(dev, pos, l);

    if (!dev->mmio_always_on)
        pci_write_config_word(dev, PCI_COMMAND, orig_cmd);

    /*
     * All bits set in sz means the device isn't working properly.
     * If the BAR isn't implemented, all bits must be 0.  If it's a
     * memory BAR or a ROM, bit 0 must be clear; if it's an io BAR, bit
     * 1 must be clear.
     */
    if (!sz || sz == 0xffffffff)
        goto fail;

    /*
     * I don't know how l can have all bits set.  Copied from old code.
     * Maybe it fixes a bug on some ancient platform.
     */
    if (l == 0xffffffff)
        l = 0;

    if (type == pci_bar_unknown) {
        type = decode_bar(res, l);
        res->flags |= pci_calc_resource_flags(l) | IORESOURCE_SIZEALIGN;
        if (type == pci_bar_io) {
            l &= PCI_BASE_ADDRESS_IO_MASK;
            mask = PCI_BASE_ADDRESS_IO_MASK & IO_SPACE_LIMIT;
        } else {
            l &= PCI_BASE_ADDRESS_MEM_MASK;
            mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;
        }
    } else {
        res->flags |= (l & IORESOURCE_ROM_ENABLE);
        l &= PCI_ROM_ADDRESS_MASK;
        mask = (u32)PCI_ROM_ADDRESS_MASK;
    }

    if (type == pci_bar_mem64) {
        u64 l64 = l;
        u64 sz64 = sz;
        u64 mask64 = mask | (u64)~0 << 32;

        pci_read_config_dword(dev, pos + 4, &l);
        pci_write_config_dword(dev, pos + 4, ~0);
        pci_read_config_dword(dev, pos + 4, &sz);
        pci_write_config_dword(dev, pos + 4, l);

        l64 |= ((u64)l << 32);
        sz64 |= ((u64)sz << 32);

        sz64 = pci_size(l64, sz64, mask64);

        if (!sz64)
            goto fail;

        if ((sizeof(resource_size_t) < 8) && (sz64 > 0x100000000ULL)) {
            dbgprintf("%s reg %x: can't handle 64-bit BAR\n",
                __FUNCTION__, pos);
            goto fail;
        }

        res->flags |= IORESOURCE_MEM_64;
        if ((sizeof(resource_size_t) < 8) && l) {
            /* Address above 32-bit boundary; disable the BAR */
            pci_write_config_dword(dev, pos, 0);
            pci_write_config_dword(dev, pos + 4, 0);
            res->start = 0;
            res->end = sz64;
        } else {
            res->start = l64;
            res->end = l64 + sz64;
        dbgprintf("%s reg %x: %pR\n", __FUNCTION__, pos, res);
        }
    } else {
        sz = pci_size(l, sz, mask);

        if (!sz)
            goto fail;

        res->start = l;
        res->end = l + sz;

        dbgprintf("%s reg %x: %pR\n", __FUNCTION__, pos, res);
    }

 out:
    return (type == pci_bar_mem64) ? 1 : 0;
 fail:
    res->flags = 0;
    goto out;
}

static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
{
    unsigned int pos, reg;

    for (pos = 0; pos < howmany; pos++) {
        struct resource *res = &dev->resource[pos];
        reg = PCI_BASE_ADDRESS_0 + (pos << 2);
        pos += __pci_read_base(dev, pci_bar_unknown, res, reg);
    }

    if (rom) {
        struct resource *res = &dev->resource[PCI_ROM_RESOURCE];
        dev->rom_base_reg = rom;
        res->flags = IORESOURCE_MEM | IORESOURCE_PREFETCH |
                IORESOURCE_READONLY | IORESOURCE_CACHEABLE |
                IORESOURCE_SIZEALIGN;
        __pci_read_base(dev, pci_bar_mem32, res, rom);
    }
}

#if 0

void pci_read_bridge_bases(struct pci_bus *child)
{
    struct pci_dev *dev = child->self;
    struct resource *res;
    int i;

    if (pci_is_root_bus(child)) /* It's a host bus, nothing to read */
        return;

    dbgprintf("PCI bridge to [bus %02x-%02x]%s\n",
         child->secondary, child->subordinate,
         dev->transparent ? " (subtractive decode)" : "");

    pci_bus_remove_resources(child);
    for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
        child->resource[i] = &dev->resource[PCI_BRIDGE_RESOURCES+i];

    pci_read_bridge_io(child);
    pci_read_bridge_mmio(child);
    pci_read_bridge_mmio_pref(child);

    if (dev->transparent) {
        pci_bus_for_each_resource(child->parent, res, i) {
            if (res) {
                pci_bus_add_resource(child, res,
                             PCI_SUBTRACTIVE_DECODE);
                dbgprintf("  bridge window %pR (subtractive decode)\n", res);
            }
        }
    }
}

#endif

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

    b = kzalloc(sizeof(*b), GFP_KERNEL);
    if (b) {
        INIT_LIST_HEAD(&b->node);
        INIT_LIST_HEAD(&b->children);
        INIT_LIST_HEAD(&b->devices);
        INIT_LIST_HEAD(&b->slots);
        INIT_LIST_HEAD(&b->resources);
//        b->max_bus_speed = PCI_SPEED_UNKNOWN;
//        b->cur_bus_speed = PCI_SPEED_UNKNOWN;
    }
    return b;
}


#if 0

static unsigned char pcix_bus_speed[] = {
    PCI_SPEED_UNKNOWN,      /* 0 */
    PCI_SPEED_66MHz_PCIX,       /* 1 */
    PCI_SPEED_100MHz_PCIX,      /* 2 */
    PCI_SPEED_133MHz_PCIX,      /* 3 */
    PCI_SPEED_UNKNOWN,      /* 4 */
    PCI_SPEED_66MHz_PCIX_ECC,   /* 5 */
    PCI_SPEED_100MHz_PCIX_ECC,  /* 6 */
    PCI_SPEED_133MHz_PCIX_ECC,  /* 7 */
    PCI_SPEED_UNKNOWN,      /* 8 */
    PCI_SPEED_66MHz_PCIX_266,   /* 9 */
    PCI_SPEED_100MHz_PCIX_266,  /* A */
    PCI_SPEED_133MHz_PCIX_266,  /* B */
    PCI_SPEED_UNKNOWN,      /* C */
    PCI_SPEED_66MHz_PCIX_533,   /* D */
    PCI_SPEED_100MHz_PCIX_533,  /* E */
    PCI_SPEED_133MHz_PCIX_533   /* F */
};

static unsigned char pcie_link_speed[] = {
    PCI_SPEED_UNKNOWN,      /* 0 */
    PCIE_SPEED_2_5GT,       /* 1 */
    PCIE_SPEED_5_0GT,       /* 2 */
    PCIE_SPEED_8_0GT,       /* 3 */
    PCI_SPEED_UNKNOWN,      /* 4 */
    PCI_SPEED_UNKNOWN,      /* 5 */
    PCI_SPEED_UNKNOWN,      /* 6 */
    PCI_SPEED_UNKNOWN,      /* 7 */
    PCI_SPEED_UNKNOWN,      /* 8 */
    PCI_SPEED_UNKNOWN,      /* 9 */
    PCI_SPEED_UNKNOWN,      /* A */
    PCI_SPEED_UNKNOWN,      /* B */
    PCI_SPEED_UNKNOWN,      /* C */
    PCI_SPEED_UNKNOWN,      /* D */
    PCI_SPEED_UNKNOWN,      /* E */
    PCI_SPEED_UNKNOWN       /* F */
};


static void pci_set_bus_speed(struct pci_bus *bus)
{
    struct pci_dev *bridge = bus->self;
    int pos;

    pos = pci_find_capability(bridge, PCI_CAP_ID_AGP);
    if (!pos)
        pos = pci_find_capability(bridge, PCI_CAP_ID_AGP3);
    if (pos) {
        u32 agpstat, agpcmd;

        pci_read_config_dword(bridge, pos + PCI_AGP_STATUS, &agpstat);
        bus->max_bus_speed = agp_speed(agpstat & 8, agpstat & 7);

        pci_read_config_dword(bridge, pos + PCI_AGP_COMMAND, &agpcmd);
        bus->cur_bus_speed = agp_speed(agpstat & 8, agpcmd & 7);
    }

    pos = pci_find_capability(bridge, PCI_CAP_ID_PCIX);
    if (pos) {
        u16 status;
        enum pci_bus_speed max;
        pci_read_config_word(bridge, pos + 2, &status);

        if (status & 0x8000) {
            max = PCI_SPEED_133MHz_PCIX_533;
        } else if (status & 0x4000) {
            max = PCI_SPEED_133MHz_PCIX_266;
        } else if (status & 0x0002) {
            if (((status >> 12) & 0x3) == 2) {
                max = PCI_SPEED_133MHz_PCIX_ECC;
            } else {
                max = PCI_SPEED_133MHz_PCIX;
            }
        } else {
            max = PCI_SPEED_66MHz_PCIX;
        }

        bus->max_bus_speed = max;
        bus->cur_bus_speed = pcix_bus_speed[(status >> 6) & 0xf];

        return;
    }

    pos = pci_find_capability(bridge, PCI_CAP_ID_EXP);
    if (pos) {
        u32 linkcap;
        u16 linksta;

        pci_read_config_dword(bridge, pos + PCI_EXP_LNKCAP, &linkcap);
        bus->max_bus_speed = pcie_link_speed[linkcap & 0xf];

        pci_read_config_word(bridge, pos + PCI_EXP_LNKSTA, &linksta);
        pcie_update_link_speed(bus, linksta);
    }
}

#endif


static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
                       struct pci_dev *bridge, int busnr)
{
    struct pci_bus *child;
    int i;

    /*
     * Allocate a new bus, and inherit stuff from the parent..
     */
    child = pci_alloc_bus();
    if (!child)
        return NULL;

    child->parent = parent;
    child->ops = parent->ops;
    child->sysdata = parent->sysdata;
    child->bus_flags = parent->bus_flags;

    /* initialize some portions of the bus device, but don't register it
     * now as the parent is not properly set up yet.  This device will get
     * registered later in pci_bus_add_devices()
     */
//    child->dev.class = &pcibus_class;
//    dev_set_name(&child->dev, "%04x:%02x", pci_domain_nr(child), busnr);

    /*
     * Set up the primary, secondary and subordinate
     * bus numbers.
     */
    child->number = child->secondary = busnr;
    child->primary = parent->secondary;
    child->subordinate = 0xff;

    if (!bridge)
        return child;

    child->self = bridge;
//    child->bridge = get_device(&bridge->dev);

//    pci_set_bus_speed(child);

    /* Set up default resource pointers and names.. */
    for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) {
        child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i];
        child->resource[i]->name = child->name;
    }
    bridge->subordinate = child;

    return child;
}

struct pci_bus* pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev, int busnr)
{
    struct pci_bus *child;

    child = pci_alloc_child_bus(parent, dev, busnr);
    if (child) {
//        down_write(&pci_bus_sem);
        list_add_tail(&child->node, &parent->children);
//        up_write(&pci_bus_sem);
    }
    return child;
}


static void pci_fixup_parent_subordinate_busnr(struct pci_bus *child, int max)
{
    struct pci_bus *parent = child->parent;

    /* Attempts to fix that up are really dangerous unless
       we're going to re-assign all bus numbers. */
    if (!pcibios_assign_all_busses())
        return;

    while (parent->parent && parent->subordinate < max) {
        parent->subordinate = max;
        pci_write_config_byte(parent->self, PCI_SUBORDINATE_BUS, max);
        parent = parent->parent;
    }
}


/*
 * If it's a bridge, configure it and scan the bus behind it.
 * For CardBus bridges, we don't scan behind as the devices will
 * be handled by the bridge driver itself.
 *
 * We need to process bridges in two passes -- first we scan those
 * already configured by the BIOS and after we are done with all of
 * them, we proceed to assigning numbers to the remaining buses in
 * order to avoid overlaps between old and new bus numbers.
 */
int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
{
    struct pci_bus *child;
    int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
    u32 buses, i, j = 0;
    u16 bctl;
    u8 primary, secondary, subordinate;
    int broken = 0;

    pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);
    primary = buses & 0xFF;
    secondary = (buses >> 8) & 0xFF;
    subordinate = (buses >> 16) & 0xFF;

    dbgprintf("scanning [bus %02x-%02x] behind bridge, pass %d\n",
        secondary, subordinate, pass);

    /* Check if setup is sensible at all */
    if (!pass &&
        (primary != bus->number || secondary <= bus->number)) {
        dbgprintf("bus configuration invalid, reconfiguring\n");
        broken = 1;
    }

    /* Disable MasterAbortMode during probing to avoid reporting
       of bus errors (in some architectures) */
    pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &bctl);
    pci_write_config_word(dev, PCI_BRIDGE_CONTROL,
                  bctl & ~PCI_BRIDGE_CTL_MASTER_ABORT);

    if ((secondary || subordinate) && !pcibios_assign_all_busses() &&
        !is_cardbus && !broken) {
        unsigned int cmax;
        /*
         * Bus already configured by firmware, process it in the first
         * pass and just note the configuration.
         */
        if (pass)
            goto out;

        /*
         * If we already got to this bus through a different bridge,
         * don't re-add it. This can happen with the i450NX chipset.
         *
         * However, we continue to descend down the hierarchy and
         * scan remaining child buses.
         */
        child = pci_find_bus(pci_domain_nr(bus), secondary);
        if (!child) {
            child = pci_add_new_bus(bus, dev, secondary);
            if (!child)
                goto out;
            child->primary = primary;
            child->subordinate = subordinate;
            child->bridge_ctl = bctl;
        }

        cmax = pci_scan_child_bus(child);
        if (cmax > max)
            max = cmax;
        if (child->subordinate > max)
            max = child->subordinate;
    } else {
        /*
         * We need to assign a number to this bus which we always
         * do in the second pass.
         */
        if (!pass) {
            if (pcibios_assign_all_busses() || broken)
                /* Temporarily disable forwarding of the
                   configuration cycles on all bridges in
                   this bus segment to avoid possible
                   conflicts in the second pass between two
                   bridges programmed with overlapping
                   bus ranges. */
                pci_write_config_dword(dev, PCI_PRIMARY_BUS,
                               buses & ~0xffffff);
            goto out;
        }

        /* Clear errors */
        pci_write_config_word(dev, PCI_STATUS, 0xffff);

        /* Prevent assigning a bus number that already exists.
         * This can happen when a bridge is hot-plugged */
        if (pci_find_bus(pci_domain_nr(bus), max+1))
            goto out;
        child = pci_add_new_bus(bus, dev, ++max);
        buses = (buses & 0xff000000)
              | ((unsigned int)(child->primary)     <<  0)
              | ((unsigned int)(child->secondary)   <<  8)
              | ((unsigned int)(child->subordinate) << 16);

        /*
         * yenta.c forces a secondary latency timer of 176.
         * Copy that behaviour here.
         */
        if (is_cardbus) {
            buses &= ~0xff000000;
            buses |= CARDBUS_LATENCY_TIMER << 24;
        }

        /*
         * We need to blast all three values with a single write.
         */
        pci_write_config_dword(dev, PCI_PRIMARY_BUS, buses);

        if (!is_cardbus) {
            child->bridge_ctl = bctl;
            /*
             * Adjust subordinate busnr in parent buses.
             * We do this before scanning for children because
             * some devices may not be detected if the bios
             * was lazy.
             */
            pci_fixup_parent_subordinate_busnr(child, max);
            /* Now we can scan all subordinate buses... */
            max = pci_scan_child_bus(child);
            /*
             * now fix it up again since we have found
             * the real value of max.
             */
            pci_fixup_parent_subordinate_busnr(child, max);
        } else {
            /*
             * For CardBus bridges, we leave 4 bus numbers
             * as cards with a PCI-to-PCI bridge can be
             * inserted later.
             */
            for (i=0; i<CARDBUS_RESERVE_BUSNR; i++) {
                struct pci_bus *parent = bus;
                if (pci_find_bus(pci_domain_nr(bus),
                            max+i+1))
                    break;
                while (parent->parent) {
                    if ((!pcibios_assign_all_busses()) &&
                        (parent->subordinate > max) &&
                        (parent->subordinate <= max+i)) {
                        j = 1;
                    }
                    parent = parent->parent;
                }
                if (j) {
                    /*
                     * Often, there are two cardbus bridges
                     * -- try to leave one valid bus number
                     * for each one.
                     */
                    i /= 2;
                    break;
                }
            }
            max += i;
            pci_fixup_parent_subordinate_busnr(child, max);
        }
        /*
         * Set the subordinate bus number to its real value.
         */
        child->subordinate = max;
        pci_write_config_byte(dev, PCI_SUBORDINATE_BUS, max);
    }

    vsprintf(child->name,
        (is_cardbus ? "PCI CardBus %04x:%02x" : "PCI Bus %04x:%02x"),
        pci_domain_nr(bus), child->number);

    /* Has only triggered on CardBus, fixup is in yenta_socket */
    while (bus->parent) {
        if ((child->subordinate > bus->subordinate) ||
            (child->number > bus->subordinate) ||
            (child->number < bus->number) ||
            (child->subordinate < bus->number)) {
            dbgprintf("[bus %02x-%02x] %s "
                "hidden behind%s bridge %s [bus %02x-%02x]\n",
                child->number, child->subordinate,
                (bus->number > child->subordinate &&
                 bus->subordinate < child->number) ?
                    "wholly" : "partially",
                bus->self->transparent ? " transparent" : "",
                "FIX BRIDGE NAME",
                bus->number, bus->subordinate);
        }
        bus = bus->parent;
    }

out:
    pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl);

    return max;
}

void set_pcie_port_type(struct pci_dev *pdev)
{
    int pos;
    u16 reg16;

    pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
    if (!pos)
        return;
    pdev->is_pcie = 1;
    pdev->pcie_cap = pos;
    pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &reg16);
    pdev->pcie_type = (reg16 & PCI_EXP_FLAGS_TYPE) >> 4;
}

void set_pcie_hotplug_bridge(struct pci_dev *pdev)
{
    int pos;
    u16 reg16;
    u32 reg32;

    pos = pci_pcie_cap(pdev);
    if (!pos)
        return;
    pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &reg16);
    if (!(reg16 & PCI_EXP_FLAGS_SLOT))
        return;
    pci_read_config_dword(pdev, pos + PCI_EXP_SLTCAP, &reg32);
    if (reg32 & PCI_EXP_SLTCAP_HPC)
        pdev->is_hotplug_bridge = 1;
}

/*
 * Read interrupt line and base address registers.
 * The architecture-dependent code can tweak these, of course.
 */
static void pci_read_irq(struct pci_dev *dev)
{
    unsigned char irq;

    pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &irq);
    dev->pin = irq;
    if (irq)
        pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &irq);
    dev->irq = irq;
}


/**
 * pci_setup_device - fill in class and map information of a device
 * @dev: the device structure to fill
 *
 * Initialize the device structure with information about the device's
 * vendor,class,memory and IO-space addresses,IRQ lines etc.
 * Called at initialisation of the PCI subsystem and by CardBus services.
 * Returns 0 on success and negative if unknown type of device (not normal,
 * bridge or CardBus).
 */
int pci_setup_device(struct pci_dev *dev)
{
    u32 class;
    u8 hdr_type;
    struct pci_slot *slot;
    int pos = 0;

    if (pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type))
        return -EIO;

    dev->sysdata = dev->bus->sysdata;
//    dev->dev.parent = dev->bus->bridge;
//    dev->dev.bus = &pci_bus_type;
    dev->hdr_type = hdr_type & 0x7f;
    dev->multifunction = !!(hdr_type & 0x80);
    dev->error_state = pci_channel_io_normal;
    set_pcie_port_type(dev);

    list_for_each_entry(slot, &dev->bus->slots, list)
        if (PCI_SLOT(dev->devfn) == slot->number)
            dev->slot = slot;

    /* Assume 32-bit PCI; let 64-bit PCI cards (which are far rarer)
       set this higher, assuming the system even supports it.  */
    dev->dma_mask = 0xffffffff;

//    dev_set_name(&dev->dev, "%04x:%02x:%02x.%d", pci_domain_nr(dev->bus),
//             dev->bus->number, PCI_SLOT(dev->devfn),
//             PCI_FUNC(dev->devfn));

    pci_read_config_dword(dev, PCI_CLASS_REVISION, &class);
    dev->revision = class & 0xff;
    class >>= 8;                    /* upper 3 bytes */
    dev->class = class;
    class >>= 8;

    dbgprintf("found [%04x:%04x] class %06x header type %02x\n",
         dev->vendor, dev->device, class, dev->hdr_type);

    /* need to have dev->class ready */
    dev->cfg_size = pci_cfg_space_size(dev);

    /* "Unknown power state" */
    dev->current_state = PCI_UNKNOWN;

    /* Early fixups, before probing the BARs */
//    pci_fixup_device(pci_fixup_early, dev);
    /* device class may be changed after fixup */
    class = dev->class >> 8;

    switch (dev->hdr_type) {            /* header type */
    case PCI_HEADER_TYPE_NORMAL:            /* standard header */
        if (class == PCI_CLASS_BRIDGE_PCI)
            goto bad;
        pci_read_irq(dev);
        pci_read_bases(dev, 6, PCI_ROM_ADDRESS);
        pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, &dev->subsystem_vendor);
        pci_read_config_word(dev, PCI_SUBSYSTEM_ID, &dev->subsystem_device);

        /*
         *  Do the ugly legacy mode stuff here rather than broken chip
         *  quirk code. Legacy mode ATA controllers have fixed
         *  addresses. These are not always echoed in BAR0-3, and
         *  BAR0-3 in a few cases contain junk!
         */
        if (class == PCI_CLASS_STORAGE_IDE) {
            u8 progif;
            pci_read_config_byte(dev, PCI_CLASS_PROG, &progif);
            if ((progif & 1) == 0) {
                dev->resource[0].start = 0x1F0;
                dev->resource[0].end = 0x1F7;
                dev->resource[0].flags = LEGACY_IO_RESOURCE;
                dev->resource[1].start = 0x3F6;
                dev->resource[1].end = 0x3F6;
                dev->resource[1].flags = LEGACY_IO_RESOURCE;
            }
            if ((progif & 4) == 0) {
                dev->resource[2].start = 0x170;
                dev->resource[2].end = 0x177;
                dev->resource[2].flags = LEGACY_IO_RESOURCE;
                dev->resource[3].start = 0x376;
                dev->resource[3].end = 0x376;
                dev->resource[3].flags = LEGACY_IO_RESOURCE;
            }
        }
        break;

    case PCI_HEADER_TYPE_BRIDGE:            /* bridge header */
        if (class != PCI_CLASS_BRIDGE_PCI)
            goto bad;
        /* The PCI-to-PCI bridge spec requires that subtractive
           decoding (i.e. transparent) bridge must have programming
           interface code of 0x01. */
        pci_read_irq(dev);
        dev->transparent = ((dev->class & 0xff) == 1);
        pci_read_bases(dev, 2, PCI_ROM_ADDRESS1);
        set_pcie_hotplug_bridge(dev);
        pos = pci_find_capability(dev, PCI_CAP_ID_SSVID);
        if (pos) {
            pci_read_config_word(dev, pos + PCI_SSVID_VENDOR_ID, &dev->subsystem_vendor);
            pci_read_config_word(dev, pos + PCI_SSVID_DEVICE_ID, &dev->subsystem_device);
        }
        break;

    case PCI_HEADER_TYPE_CARDBUS:           /* CardBus bridge header */
        if (class != PCI_CLASS_BRIDGE_CARDBUS)
            goto bad;
        pci_read_irq(dev);
        pci_read_bases(dev, 1, 0);
        pci_read_config_word(dev, PCI_CB_SUBSYSTEM_VENDOR_ID, &dev->subsystem_vendor);
        pci_read_config_word(dev, PCI_CB_SUBSYSTEM_ID, &dev->subsystem_device);
        break;

    default:                    /* unknown header */
        dbgprintf("unknown header type %02x, "
            "ignoring device\n", dev->hdr_type);
        return -EIO;

    bad:
        dbgprintf("ignoring class %02x (doesn't match header "
            "type %02x)\n", class, dev->hdr_type);
        dev->class = PCI_CLASS_NOT_DEFINED;
    }

    /* We found a fine healthy device, go go go... */
    return 0;
}



struct pci_dev *alloc_pci_dev(void)
{
    struct pci_dev *dev;

    dev = kzalloc(sizeof(struct pci_dev), GFP_KERNEL);
    if (!dev)
        return NULL;

    INIT_LIST_HEAD(&dev->bus_list);

    return dev;
}

/*
 * Read the config data for a PCI device, sanity-check it
 * and fill in the dev structure...
 */
static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
{
    struct pci_dev *dev;
    u32 l;
    int timeout = 10;

    if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, &l))
        return NULL;

    /* some broken boards return 0 or ~0 if a slot is empty: */
    if (l == 0xffffffff || l == 0x00000000 ||
        l == 0x0000ffff || l == 0xffff0000)
        return NULL;

    /* Configuration request Retry Status */
    while (l == 0xffff0001) {
        delay(timeout/10);
        timeout *= 2;
        if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, &l))
            return NULL;
        /* Card hasn't responded in 60 seconds?  Must be stuck. */
        if (timeout > 60 * 1000) {
            printk(KERN_WARNING "pci %04x:%02x:%02x.%d: not "
                    "responding\n", pci_domain_nr(bus),
                    bus->number, PCI_SLOT(devfn),
                    PCI_FUNC(devfn));
            return NULL;
        }
    }

    dev = alloc_pci_dev();
    if (!dev)
        return NULL;

    dev->bus = bus;
    dev->busnr = bus->number;
    dev->devfn = devfn;
    dev->vendor = l & 0xffff;
    dev->device = (l >> 16) & 0xffff;

    if (pci_setup_device(dev)) {
        kfree(dev);
        return NULL;
    }

    return dev;
}

void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
{
//    device_initialize(&dev->dev);
//    dev->dev.release = pci_release_dev;
//    pci_dev_get(dev);

//    dev->dev.dma_mask = &dev->dma_mask;
//    dev->dev.dma_parms = &dev->dma_parms;
//    dev->dev.coherent_dma_mask = 0xffffffffull;

//    pci_set_dma_max_seg_size(dev, 65536);
//    pci_set_dma_seg_boundary(dev, 0xffffffff);

    /* Fix up broken headers */
//    pci_fixup_device(pci_fixup_header, dev);

    /* Clear the state_saved flag. */
    dev->state_saved = false;

    /* Initialize various capabilities */
//    pci_init_capabilities(dev);

    /*
     * Add the device to our list of discovered devices
     * and the bus list for fixup functions, etc.
     */
//    down_write(&pci_bus_sem);
    list_add_tail(&dev->bus_list, &bus->devices);
//    up_write(&pci_bus_sem);
}

struct pci_dev * pci_scan_single_device(struct pci_bus *bus, int devfn)
{
    struct pci_dev *dev;

    dev = pci_get_slot(bus, devfn);
    if (dev) {
//        pci_dev_put(dev);
        return dev;
    }

    dev = pci_scan_device(bus, devfn);
    if (!dev)
        return NULL;

    pci_device_add(dev, bus);

    return dev;
}

static unsigned next_ari_fn(struct pci_dev *dev, unsigned fn)
{
    u16 cap;
    unsigned pos, next_fn;

    if (!dev)
        return 0;

    pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
    if (!pos)
        return 0;
    pci_read_config_word(dev, pos + 4, &cap);
    next_fn = cap >> 8;
    if (next_fn <= fn)
        return 0;
    return next_fn;
}

static unsigned next_trad_fn(struct pci_dev *dev, unsigned fn)
{
    return (fn + 1) % 8;
}

static unsigned no_next_fn(struct pci_dev *dev, unsigned fn)
{
    return 0;
}

static int only_one_child(struct pci_bus *bus)
{
    struct pci_dev *parent = bus->self;
    if (!parent || !pci_is_pcie(parent))
        return 0;
    if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
        parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM)
        return 1;
    return 0;
}

/**
 * pci_scan_slot - scan a PCI slot on a bus for devices.
 * @bus: PCI bus to scan
 * @devfn: slot number to scan (must have zero function.)
 *
 * Scan a PCI slot on the specified PCI bus for devices, adding
 * discovered devices to the @bus->devices list.  New devices
 * will not have is_added set.
 *
 * Returns the number of new devices found.
 */
int pci_scan_slot(struct pci_bus *bus, int devfn)
{
    unsigned fn, nr = 0;
    struct pci_dev *dev;
    unsigned (*next_fn)(struct pci_dev *, unsigned) = no_next_fn;

    if (only_one_child(bus) && (devfn > 0))
        return 0; /* Already scanned the entire slot */

    dev = pci_scan_single_device(bus, devfn);
    if (!dev)
        return 0;
    if (!dev->is_added)
        nr++;

    if (pci_ari_enabled(bus))
        next_fn = next_ari_fn;
    else if (dev->multifunction)
        next_fn = next_trad_fn;

    for (fn = next_fn(dev, 0); fn > 0; fn = next_fn(dev, fn)) {
        dev = pci_scan_single_device(bus, devfn + fn);
        if (dev) {
            if (!dev->is_added)
                nr++;
            dev->multifunction = 1;
        }
    }

    /* only one slot has pcie device */
//    if (bus->self && nr)
//        pcie_aspm_init_link_state(bus->self);

    return nr;
}


unsigned int pci_scan_child_bus(struct pci_bus *bus)
{
    unsigned int devfn, pass, max = bus->secondary;
    struct pci_dev *dev;

    dbgprintf("scanning bus\n");

    /* Go find them, Rover! */
    for (devfn = 0; devfn < 0x100; devfn += 8)
        pci_scan_slot(bus, devfn);

    /* Reserve buses for SR-IOV capability. */
    max += pci_iov_bus_range(bus);

    /*
     * After performing arch-dependent fixup of the bus, look behind
     * all PCI-to-PCI bridges on this bus.
     */
    if (!bus->is_added) {
        dbgprintf("fixups for bus\n");
//        pcibios_fixup_bus(bus);
        if (pci_is_root_bus(bus))
            bus->is_added = 1;
    }

    for (pass=0; pass < 2; pass++)
        list_for_each_entry(dev, &bus->devices, bus_list) {
            if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
                dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
                max = pci_scan_bridge(bus, dev, max, pass);
        }

    /*
     * We've scanned the bus and so we know all about what's on
     * the other side of any bridges that may be on this bus plus
     * any devices.
     *
     * Return how far we've got finding sub-buses.
     */
    dbgprintf("bus scan returning with max=%02x\n", max);
    return max;
}

/**
 * pci_cfg_space_size - get the configuration space size of the PCI device.
 * @dev: PCI device
 *
 * Regular PCI devices have 256 bytes, but PCI-X 2 and PCI Express devices
 * have 4096 bytes.  Even if the device is capable, that doesn't mean we can
 * access it.  Maybe we don't have a way to generate extended config space
 * accesses, or the device is behind a reverse Express bridge.  So we try
 * reading the dword at 0x100 which must either be 0 or a valid extended
 * capability header.
 */
int pci_cfg_space_size_ext(struct pci_dev *dev)
{
    u32 status;
    int pos = PCI_CFG_SPACE_SIZE;

    if (pci_read_config_dword(dev, pos, &status) != PCIBIOS_SUCCESSFUL)
        goto fail;
    if (status == 0xffffffff)
        goto fail;

    return PCI_CFG_SPACE_EXP_SIZE;

 fail:
    return PCI_CFG_SPACE_SIZE;
}

int pci_cfg_space_size(struct pci_dev *dev)
{
    int pos;
    u32 status;
    u16 class;

    class = dev->class >> 8;
    if (class == PCI_CLASS_BRIDGE_HOST)
        return pci_cfg_space_size_ext(dev);

    pos = pci_pcie_cap(dev);
    if (!pos) {
        pos = pci_find_capability(dev, PCI_CAP_ID_PCIX);
        if (!pos)
            goto fail;

        pci_read_config_dword(dev, pos + PCI_X_STATUS, &status);
        if (!(status & (PCI_X_STATUS_266MHZ | PCI_X_STATUS_533MHZ)))
            goto fail;
    }

    return pci_cfg_space_size_ext(dev);

 fail:
    return PCI_CFG_SPACE_SIZE;
}



struct pci_bus * pci_create_bus(int bus, struct pci_ops *ops, void *sysdata)
{
    int error;
    struct pci_bus *b, *b2;

    b = pci_alloc_bus();
    if (!b)
        return NULL;

    b->sysdata = sysdata;
    b->ops = ops;

    b2 = pci_find_bus(pci_domain_nr(b), bus);
    if (b2) {
        /* If we already got to this bus through a different bridge, ignore it */
        dbgprintf("bus already known\n");
        goto err_out;
    }

//    down_write(&pci_bus_sem);
    list_add_tail(&b->node, &pci_root_buses);
//    up_write(&pci_bus_sem);

    b->number = b->secondary = bus;
    b->resource[0] = &ioport_resource;
    b->resource[1] = &iomem_resource;

    return b;

err_out:
    kfree(b);
    return NULL;
}