Archipelago » qemu

/*

 * QEMU PCI bus manager

 *

 * Copyright (c) 2004 Fabrice Bellard

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "hw.h"

#include "pci.h"

#include "monitor.h"

#include "net.h"

#include "virtio-net.h"

#include "sysemu.h"

//#define DEBUG_PCI

struct PCIBus {

    int bus_num;

    int devfn_min;

    pci_set_irq_fn set_irq;

    pci_map_irq_fn map_irq;

    uint32_t config_reg; /* XXX: suppress */

    /* low level pic */

    SetIRQFunc *low_set_irq;

    qemu_irq *irq_opaque;

    PCIDevice *devices[256];

    PCIDevice *parent_dev;

    PCIBus *next;

    /* The bus IRQ state is the logical OR of the connected devices.

       Keep a count of the number of devices with raised IRQs.  */

    int nirq;

    int irq_count[];

};

static void pci_update_mappings(PCIDevice *d);

static void pci_set_irq(void *opaque, int irq_num, int level);

target_phys_addr_t pci_mem_base;

static uint16_t pci_default_sub_vendor_id = PCI_SUBVENDOR_ID_REDHAT_QUMRANET;

static uint16_t pci_default_sub_device_id = PCI_SUBDEVICE_ID_QEMU;

static int pci_irq_index;

static PCIBus *first_bus;

static void pcibus_save(QEMUFile *f, void *opaque)

{

    PCIBus *bus = (PCIBus *)opaque;

    int i;

    qemu_put_be32(f, bus->nirq);

    for (i = 0; i < bus->nirq; i++)

        qemu_put_be32(f, bus->irq_count[i]);

}

static int  pcibus_load(QEMUFile *f, void *opaque, int version_id)

{

    PCIBus *bus = (PCIBus *)opaque;

    int i, nirq;

    if (version_id != 1)

        return -EINVAL;

    nirq = qemu_get_be32(f);

    if (bus->nirq != nirq) {

        fprintf(stderr, "pcibus_load: nirq mismatch: src=%d dst=%d\n",

                nirq, bus->nirq);

        return -EINVAL;

    }

    for (i = 0; i < nirq; i++)

        bus->irq_count[i] = qemu_get_be32(f);

    return 0;

}

PCIBus *pci_register_bus(pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,

                         qemu_irq *pic, int devfn_min, int nirq)

{

    PCIBus *bus;

    static int nbus = 0;

    bus = qemu_mallocz(sizeof(PCIBus) + (nirq * sizeof(int)));

    bus->set_irq = set_irq;

    bus->map_irq = map_irq;

    bus->irq_opaque = pic;

    bus->devfn_min = devfn_min;

    bus->nirq = nirq;

    first_bus = bus;

    register_savevm("PCIBUS", nbus++, 1, pcibus_save, pcibus_load, bus);

    return bus;

}

static PCIBus *pci_register_secondary_bus(PCIDevice *dev, pci_map_irq_fn map_irq)

{

    PCIBus *bus;

    bus = qemu_mallocz(sizeof(PCIBus));

    bus->map_irq = map_irq;

    bus->parent_dev = dev;

    bus->next = dev->bus->next;

    dev->bus->next = bus;

    return bus;

}

int pci_bus_num(PCIBus *s)

{

    return s->bus_num;

}

void pci_device_save(PCIDevice *s, QEMUFile *f)

{

    int i;

    qemu_put_be32(f, 2); /* PCI device version */

    qemu_put_buffer(f, s->config, 256);

    for (i = 0; i < 4; i++)

        qemu_put_be32(f, s->irq_state[i]);

}

int pci_device_load(PCIDevice *s, QEMUFile *f)

{

    uint32_t version_id;

    int i;

    version_id = qemu_get_be32(f);

    if (version_id > 2)

        return -EINVAL;

    qemu_get_buffer(f, s->config, 256);

    pci_update_mappings(s);

    if (version_id >= 2)

        for (i = 0; i < 4; i ++)

            s->irq_state[i] = qemu_get_be32(f);

    return 0;

}

static int pci_set_default_subsystem_id(PCIDevice *pci_dev)

{

    uint16_t *id;

    id = (void*)(&pci_dev->config[PCI_SUBVENDOR_ID]);

    id[0] = cpu_to_le16(pci_default_sub_vendor_id);

    id[1] = cpu_to_le16(pci_default_sub_device_id);

    return 0;

}

/*

 * Parse [[<domain>:]<bus>:]<slot>, return -1 on error

 */

static int pci_parse_devaddr(const char *addr, int *domp, int *busp, unsigned *slotp)

{

    const char *p;

    char *e;

    unsigned long val;

    unsigned long dom = 0, bus = 0;

    unsigned slot = 0;

    p = addr;

    val = strtoul(p, &e, 16);

    if (e == p)

        return -1;

    if (*e == ':') {

        bus = val;

        p = e + 1;

        val = strtoul(p, &e, 16);

        if (e == p)

            return -1;

        if (*e == ':') {

            dom = bus;

            bus = val;

            p = e + 1;

            val = strtoul(p, &e, 16);

            if (e == p)

                return -1;

        }

    }

    if (dom > 0xffff || bus > 0xff || val > 0x1f)

        return -1;

    slot = val;

    if (*e)

        return -1;

    /* Note: QEMU doesn't implement domains other than 0 */

    if (dom != 0 || pci_find_bus(bus) == NULL)

        return -1;

    *domp = dom;

    *busp = bus;

    *slotp = slot;

    return 0;

}

int pci_read_devaddr(const char *addr, int *domp, int *busp, unsigned *slotp)

{

    char devaddr[32];

    if (!get_param_value(devaddr, sizeof(devaddr), "pci_addr", addr))

        return -1;

    return pci_parse_devaddr(devaddr, domp, busp, slotp);

}

int pci_assign_devaddr(const char *addr, int *domp, int *busp, unsigned *slotp)

{

    char devaddr[32];

    if (!get_param_value(devaddr, sizeof(devaddr), "pci_addr", addr))

        return -1;

    if (!strcmp(devaddr, "auto")) {

        *domp = *busp = 0;

        *slotp = -1;

        /* want to support dom/bus auto-assign at some point */

        return 0;

    }

    return pci_parse_devaddr(devaddr, domp, busp, slotp);

}

/* -1 for devfn means auto assign */

PCIDevice *pci_register_device(PCIBus *bus, const char *name,

                               int instance_size, int devfn,

                               PCIConfigReadFunc *config_read,

                               PCIConfigWriteFunc *config_write)

{

    PCIDevice *pci_dev;

    if (pci_irq_index >= PCI_DEVICES_MAX)

        return NULL;

    if (devfn < 0) {

        for(devfn = bus->devfn_min ; devfn < 256; devfn += 8) {

            if (!bus->devices[devfn])

                goto found;

        }

        return NULL;

    found: ;

    }

    pci_dev = qemu_mallocz(instance_size);

    pci_dev->bus = bus;

    pci_dev->devfn = devfn;

    pstrcpy(pci_dev->name, sizeof(pci_dev->name), name);

    memset(pci_dev->irq_state, 0, sizeof(pci_dev->irq_state));

    pci_set_default_subsystem_id(pci_dev);

    if (!config_read)

        config_read = pci_default_read_config;

    if (!config_write)

        config_write = pci_default_write_config;

    pci_dev->config_read = config_read;

    pci_dev->config_write = config_write;

    pci_dev->irq_index = pci_irq_index++;

    bus->devices[devfn] = pci_dev;

    pci_dev->irq = qemu_allocate_irqs(pci_set_irq, pci_dev, 4);

    return pci_dev;

}

static target_phys_addr_t pci_to_cpu_addr(target_phys_addr_t addr)

{

    return addr + pci_mem_base;

}

static void pci_unregister_io_regions(PCIDevice *pci_dev)

{

    PCIIORegion *r;

    int i;

    for(i = 0; i < PCI_NUM_REGIONS; i++) {

        r = &pci_dev->io_regions[i];

        if (!r->size || r->addr == -1)

            continue;

        if (r->type == PCI_ADDRESS_SPACE_IO) {

            isa_unassign_ioport(r->addr, r->size);

        } else {

            cpu_register_physical_memory(pci_to_cpu_addr(r->addr),

                                                     r->size,

                                                     IO_MEM_UNASSIGNED);

        }

    }

}

int pci_unregister_device(PCIDevice *pci_dev)

{

    int ret = 0;

    if (pci_dev->unregister)

        ret = pci_dev->unregister(pci_dev);

    if (ret)

        return ret;

    pci_unregister_io_regions(pci_dev);

    qemu_free_irqs(pci_dev->irq);

    pci_irq_index--;

    pci_dev->bus->devices[pci_dev->devfn] = NULL;

    qemu_free(pci_dev);

    return 0;

}

void pci_register_io_region(PCIDevice *pci_dev, int region_num,

                            uint32_t size, int type,

                            PCIMapIORegionFunc *map_func)

{

    PCIIORegion *r;

    uint32_t addr;

    if ((unsigned int)region_num >= PCI_NUM_REGIONS)

        return;

    if (size & (size-1)) {

        fprintf(stderr, "ERROR: PCI region size must be pow2 "

                    "type=0x%x, size=0x%x\n", type, size);

        exit(1);

    }

    r = &pci_dev->io_regions[region_num];

    r->addr = -1;

    r->size = size;

    r->type = type;

    r->map_func = map_func;

    if (region_num == PCI_ROM_SLOT) {

        addr = 0x30;

    } else {

        addr = 0x10 + region_num * 4;

    }

    *(uint32_t *)(pci_dev->config + addr) = cpu_to_le32(type);

}

static void pci_update_mappings(PCIDevice *d)

{

    PCIIORegion *r;

    int cmd, i;

    uint32_t last_addr, new_addr, config_ofs;

    cmd = le16_to_cpu(*(uint16_t *)(d->config + PCI_COMMAND));

    for(i = 0; i < PCI_NUM_REGIONS; i++) {

        r = &d->io_regions[i];

        if (i == PCI_ROM_SLOT) {

            config_ofs = 0x30;

        } else {

            config_ofs = 0x10 + i * 4;

        }

        if (r->size != 0) {

            if (r->type & PCI_ADDRESS_SPACE_IO) {

                if (cmd & PCI_COMMAND_IO) {

                    new_addr = le32_to_cpu(*(uint32_t *)(d->config +

                                                         config_ofs));

                    new_addr = new_addr & ~(r->size - 1);

                    last_addr = new_addr + r->size - 1;

                    /* NOTE: we have only 64K ioports on PC */

                    if (last_addr <= new_addr || new_addr == 0 ||

                        last_addr >= 0x10000) {

                        new_addr = -1;

                    }

                } else {

                    new_addr = -1;

                }

            } else {

                if (cmd & PCI_COMMAND_MEMORY) {

                    new_addr = le32_to_cpu(*(uint32_t *)(d->config +

                                                         config_ofs));

                    /* the ROM slot has a specific enable bit */

                    if (i == PCI_ROM_SLOT && !(new_addr & 1))

                        goto no_mem_map;

                    new_addr = new_addr & ~(r->size - 1);

                    last_addr = new_addr + r->size - 1;

                    /* NOTE: we do not support wrapping */

                    /* XXX: as we cannot support really dynamic

                       mappings, we handle specific values as invalid

                       mappings. */

                    if (last_addr <= new_addr || new_addr == 0 ||

                        last_addr == -1) {

                        new_addr = -1;

                    }

                } else {

                no_mem_map:

                    new_addr = -1;

                }

            }

            /* now do the real mapping */

            if (new_addr != r->addr) {

                if (r->addr != -1) {

                    if (r->type & PCI_ADDRESS_SPACE_IO) {

                        int class;

                        /* NOTE: specific hack for IDE in PC case:

                           only one byte must be mapped. */

                        class = d->config[0x0a] | (d->config[0x0b] << 8);

                        if (class == 0x0101 && r->size == 4) {

                            isa_unassign_ioport(r->addr + 2, 1);

                        } else {

                            isa_unassign_ioport(r->addr, r->size);

                        }

                    } else {

                        cpu_register_physical_memory(pci_to_cpu_addr(r->addr),

                                                     r->size,

                                                     IO_MEM_UNASSIGNED);

                        qemu_unregister_coalesced_mmio(r->addr, r->size);

                    }

                }

                r->addr = new_addr;

                if (r->addr != -1) {

                    r->map_func(d, i, r->addr, r->size, r->type);

                }

            }

        }

    }

}

uint32_t pci_default_read_config(PCIDevice *d,

                                 uint32_t address, int len)

{

    uint32_t val;

    switch(len) {

    default:

    case 4:

        if (address <= 0xfc) {

            val = le32_to_cpu(*(uint32_t *)(d->config + address));

            break;

        }

        /* fall through */

    case 2:

        if (address <= 0xfe) {

            val = le16_to_cpu(*(uint16_t *)(d->config + address));

            break;

        }

        /* fall through */

    case 1:

        val = d->config[address];

        break;

    }

    return val;

}

void pci_default_write_config(PCIDevice *d,

                              uint32_t address, uint32_t val, int len)

{

    int can_write, i;

    uint32_t end, addr;

    if (len == 4 && ((address >= 0x10 && address < 0x10 + 4 * 6) ||

                     (address >= 0x30 && address < 0x34))) {

        PCIIORegion *r;

        int reg;

        if ( address >= 0x30 ) {

            reg = PCI_ROM_SLOT;

        }else{

            reg = (address - 0x10) >> 2;

        }

        r = &d->io_regions[reg];

        if (r->size == 0)

            goto default_config;

        /* compute the stored value */

        if (reg == PCI_ROM_SLOT) {

            /* keep ROM enable bit */

            val &= (~(r->size - 1)) | 1;

        } else {

            val &= ~(r->size - 1);

            val |= r->type;

        }

        *(uint32_t *)(d->config + address) = cpu_to_le32(val);

        pci_update_mappings(d);

        return;

    }

 default_config:

    /* not efficient, but simple */

    addr = address;

    for(i = 0; i < len; i++) {

        /* default read/write accesses */

        switch(d->config[0x0e]) {

        case 0x00:

        case 0x80:

            switch(addr) {

            case 0x00:

            case 0x01:

            case 0x02:

            case 0x03:

            case 0x08:

            case 0x09:

            case 0x0a:

            case 0x0b:

            case 0x0e:

            case 0x10 ... 0x27: /* base */

            case 0x2c ... 0x2f: /* read-only subsystem ID & vendor ID */

            case 0x30 ... 0x33: /* rom */

            case 0x3d:

                can_write = 0;

                break;

            default:

                can_write = 1;

                break;

            }

            break;

        default:

        case 0x01:

            switch(addr) {

            case 0x00:

            case 0x01:

            case 0x02:

            case 0x03:

            case 0x08:

            case 0x09:

            case 0x0a:

            case 0x0b:

            case 0x0e:

            case 0x2c ... 0x2f: /* read-only subsystem ID & vendor ID */

            case 0x38 ... 0x3b: /* rom */

            case 0x3d:

                can_write = 0;

                break;

            default:

                can_write = 1;

                break;

            }

            break;

        }

        if (can_write) {

            /* Mask out writes to reserved bits in registers */

            switch (addr) {

            case 0x05:

                val &= ~PCI_COMMAND_RESERVED_MASK_HI;

                break;

            case 0x06:

                val &= ~PCI_STATUS_RESERVED_MASK_LO;

                break;

            case 0x07:

                val &= ~PCI_STATUS_RESERVED_MASK_HI;

                break;

            }

            d->config[addr] = val;

        }

        if (++addr > 0xff)

                break;

        val >>= 8;

    }

    end = address + len;

    if (end > PCI_COMMAND && address < (PCI_COMMAND + 2)) {

        /* if the command register is modified, we must modify the mappings */

        pci_update_mappings(d);

    }

}

void pci_data_write(void *opaque, uint32_t addr, uint32_t val, int len)

{

    PCIBus *s = opaque;

    PCIDevice *pci_dev;

    int config_addr, bus_num;

#if defined(DEBUG_PCI) && 0

    printf("pci_data_write: addr=%08x val=%08x len=%d\n",

           addr, val, len);

#endif

    bus_num = (addr >> 16) & 0xff;

    while (s && s->bus_num != bus_num)

        s = s->next;

    if (!s)

        return;

    pci_dev = s->devices[(addr >> 8) & 0xff];

    if (!pci_dev)

        return;

    config_addr = addr & 0xff;

#if defined(DEBUG_PCI)

    printf("pci_config_write: %s: addr=%02x val=%08x len=%d\n",

           pci_dev->name, config_addr, val, len);

#endif

    pci_dev->config_write(pci_dev, config_addr, val, len);

}

uint32_t pci_data_read(void *opaque, uint32_t addr, int len)

{

    PCIBus *s = opaque;

    PCIDevice *pci_dev;

    int config_addr, bus_num;

    uint32_t val;

    bus_num = (addr >> 16) & 0xff;

    while (s && s->bus_num != bus_num)

        s= s->next;

    if (!s)

        goto fail;

    pci_dev = s->devices[(addr >> 8) & 0xff];

    if (!pci_dev) {

    fail:

        switch(len) {

        case 1:

            val = 0xff;

            break;

        case 2:

            val = 0xffff;

            break;

        default:

        case 4:

            val = 0xffffffff;

            break;

        }

        goto the_end;

    }

    config_addr = addr & 0xff;

    val = pci_dev->config_read(pci_dev, config_addr, len);

#if defined(DEBUG_PCI)

    printf("pci_config_read: %s: addr=%02x val=%08x len=%d\n",

           pci_dev->name, config_addr, val, len);

#endif

 the_end:

#if defined(DEBUG_PCI) && 0

    printf("pci_data_read: addr=%08x val=%08x len=%d\n",

           addr, val, len);

#endif

    return val;

}

/***********************************************************/

/* generic PCI irq support */

/* 0 <= irq_num <= 3. level must be 0 or 1 */

static void pci_set_irq(void *opaque, int irq_num, int level)

{

    PCIDevice *pci_dev = (PCIDevice *)opaque;

    PCIBus *bus;

    int change;

    change = level - pci_dev->irq_state[irq_num];

    if (!change)

        return;

    pci_dev->irq_state[irq_num] = level;

    for (;;) {

        bus = pci_dev->bus;

        irq_num = bus->map_irq(pci_dev, irq_num);

        if (bus->set_irq)

            break;

        pci_dev = bus->parent_dev;

    }

    bus->irq_count[irq_num] += change;

    bus->set_irq(bus->irq_opaque, irq_num, bus->irq_count[irq_num] != 0);

}

/***********************************************************/

/* monitor info on PCI */

typedef struct {

    uint16_t class;

    const char *desc;

} pci_class_desc;

static const pci_class_desc pci_class_descriptions[] =

{

    { 0x0100, "SCSI controller"},

    { 0x0101, "IDE controller"},

    { 0x0102, "Floppy controller"},

    { 0x0103, "IPI controller"},

    { 0x0104, "RAID controller"},

    { 0x0106, "SATA controller"},

    { 0x0107, "SAS controller"},

    { 0x0180, "Storage controller"},

    { 0x0200, "Ethernet controller"},

    { 0x0201, "Token Ring controller"},

    { 0x0202, "FDDI controller"},

    { 0x0203, "ATM controller"},

    { 0x0280, "Network controller"},

    { 0x0300, "VGA controller"},

    { 0x0301, "XGA controller"},

    { 0x0302, "3D controller"},

    { 0x0380, "Display controller"},

    { 0x0400, "Video controller"},

    { 0x0401, "Audio controller"},

    { 0x0402, "Phone"},

    { 0x0480, "Multimedia controller"},

    { 0x0500, "RAM controller"},

    { 0x0501, "Flash controller"},

    { 0x0580, "Memory controller"},

    { 0x0600, "Host bridge"},

    { 0x0601, "ISA bridge"},

    { 0x0602, "EISA bridge"},

    { 0x0603, "MC bridge"},

    { 0x0604, "PCI bridge"},

    { 0x0605, "PCMCIA bridge"},

    { 0x0606, "NUBUS bridge"},

    { 0x0607, "CARDBUS bridge"},

    { 0x0608, "RACEWAY bridge"},

    { 0x0680, "Bridge"},

    { 0x0c03, "USB controller"},

    { 0, NULL}

};

static void pci_info_device(PCIDevice *d)

{

    Monitor *mon = cur_mon;

    int i, class;

    PCIIORegion *r;

    const pci_class_desc *desc;

    monitor_printf(mon, "  Bus %2d, device %3d, function %d:\n",

                   d->bus->bus_num, d->devfn >> 3, d->devfn & 7);

    class = le16_to_cpu(*((uint16_t *)(d->config + PCI_CLASS_DEVICE)));

    monitor_printf(mon, "    ");

    desc = pci_class_descriptions;

    while (desc->desc && class != desc->class)

        desc++;

    if (desc->desc) {

        monitor_printf(mon, "%s", desc->desc);

    } else {

        monitor_printf(mon, "Class %04x", class);

    }

    monitor_printf(mon, ": PCI device %04x:%04x\n",

           le16_to_cpu(*((uint16_t *)(d->config + PCI_VENDOR_ID))),

           le16_to_cpu(*((uint16_t *)(d->config + PCI_DEVICE_ID))));

    if (d->config[PCI_INTERRUPT_PIN] != 0) {

        monitor_printf(mon, "      IRQ %d.\n",

                       d->config[PCI_INTERRUPT_LINE]);

    }

    if (class == 0x0604) {

        monitor_printf(mon, "      BUS %d.\n", d->config[0x19]);

    }

    for(i = 0;i < PCI_NUM_REGIONS; i++) {

        r = &d->io_regions[i];

        if (r->size != 0) {

            monitor_printf(mon, "      BAR%d: ", i);

            if (r->type & PCI_ADDRESS_SPACE_IO) {

                monitor_printf(mon, "I/O at 0x%04x [0x%04x].\n",

                               r->addr, r->addr + r->size - 1);

            } else {

                monitor_printf(mon, "32 bit memory at 0x%08x [0x%08x].\n",

                               r->addr, r->addr + r->size - 1);

            }

        }

    }

    if (class == 0x0604 && d->config[0x19] != 0) {

        pci_for_each_device(d->config[0x19], pci_info_device);

    }

}

void pci_for_each_device(int bus_num, void (*fn)(PCIDevice *d))

{

    PCIBus *bus = first_bus;

    PCIDevice *d;

    int devfn;

    while (bus && bus->bus_num != bus_num)

        bus = bus->next;

    if (bus) {

        for(devfn = 0; devfn < 256; devfn++) {

            d = bus->devices[devfn];

            if (d)

                fn(d);

        }

    }

}

void pci_info(Monitor *mon)

{

    pci_for_each_device(0, pci_info_device);

}

static const char * const pci_nic_models[] = {

    "ne2k_pci",

    "i82551",

    "i82557b",

    "i82559er",

    "rtl8139",

    "e1000",

    "pcnet",

    "virtio",

    NULL

};

typedef PCIDevice *(*PCINICInitFn)(PCIBus *, NICInfo *, int);

static PCINICInitFn pci_nic_init_fns[] = {

    pci_ne2000_init,

    pci_i82551_init,

    pci_i82557b_init,

    pci_i82559er_init,

    pci_rtl8139_init,

    pci_e1000_init,

    pci_pcnet_init,

    virtio_net_init,

    NULL

};

/* Initialize a PCI NIC.  */

PCIDevice *pci_nic_init(PCIBus *bus, NICInfo *nd, int devfn,

                  const char *default_model)

{

    PCIDevice *pci_dev;

    int i;

    qemu_check_nic_model_list(nd, pci_nic_models, default_model);

    for (i = 0; pci_nic_models[i]; i++)

        if (strcmp(nd->model, pci_nic_models[i]) == 0) {

            pci_dev = pci_nic_init_fns[i](bus, nd, devfn);

            if (pci_dev)

                nd->private = pci_dev;

            return pci_dev;

        }

    return NULL;

}

typedef struct {

    PCIDevice dev;

    PCIBus *bus;

} PCIBridge;

static void pci_bridge_write_config(PCIDevice *d,

                             uint32_t address, uint32_t val, int len)

{

    PCIBridge *s = (PCIBridge *)d;

    if (address == 0x19 || (address == 0x18 && len > 1)) {

        if (address == 0x19)

            s->bus->bus_num = val & 0xff;

        else

            s->bus->bus_num = (val >> 8) & 0xff;

#if defined(DEBUG_PCI)

        printf ("pci-bridge: %s: Assigned bus %d\n", d->name, s->bus->bus_num);

#endif

    }

    pci_default_write_config(d, address, val, len);

}

PCIBus *pci_find_bus(int bus_num)

{

    PCIBus *bus = first_bus;

    while (bus && bus->bus_num != bus_num)

        bus = bus->next;

    return bus;

}

PCIDevice *pci_find_device(int bus_num, int slot, int function)

{

    PCIBus *bus = pci_find_bus(bus_num);

    if (!bus)

        return NULL;

    return bus->devices[PCI_DEVFN(slot, function)];

}

PCIBus *pci_bridge_init(PCIBus *bus, int devfn, uint16_t vid, uint16_t did,

                        pci_map_irq_fn map_irq, const char *name)

{

    PCIBridge *s;

    s = (PCIBridge *)pci_register_device(bus, name, sizeof(PCIBridge),

                                         devfn, NULL, pci_bridge_write_config);