Archipelago » qemu

/*

 * Linux host USB redirector

 *

 * Copyright (c) 2005 Fabrice Bellard

 *

 * Copyright (c) 2008 Max Krasnyansky

 *      Support for host device auto connect & disconnect

 *      Magor rewrite to support fully async operation

 *

 * 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 "qemu-common.h"

#include "qemu-timer.h"

#include "hw/usb.h"

#include "console.h"

#if defined(__linux__)

#include <dirent.h>

#include <sys/ioctl.h>

#include <linux/usbdevice_fs.h>

#include <linux/version.h>

#include <signal.h>

/* We redefine it to avoid version problems */

struct usb_ctrltransfer {

    uint8_t  bRequestType;

    uint8_t  bRequest;

    uint16_t wValue;

    uint16_t wIndex;

    uint16_t wLength;

    uint32_t timeout;

    void *data;

};

typedef int USBScanFunc(void *opaque, int bus_num, int addr, int class_id,

                        int vendor_id, int product_id,

                        const char *product_name, int speed);

static int usb_host_find_device(int *pbus_num, int *paddr,

                                char *product_name, int product_name_size,

                                const char *devname);

//#define DEBUG

#ifdef DEBUG

#define dprintf printf

#else

#define dprintf(...)

#endif

#define USBDEVFS_PATH "/proc/bus/usb"

#define PRODUCT_NAME_SZ 32

#define MAX_ENDPOINTS 16

struct sigaction sigact;

/* endpoint association data */

struct endp_data {

    uint8_t type;

    uint8_t halted;

};

typedef struct USBHostDevice {

    USBDevice dev;

    int       fd;

    uint8_t   descr[1024];

    int       descr_len;

    int       configuration;

    int       closing;

    struct endp_data endp_table[MAX_ENDPOINTS];

    /* Host side address */

    int bus_num;

    int addr;

    struct USBHostDevice *next;

} USBHostDevice;

static int is_isoc(USBHostDevice *s, int ep)

{

    return s->endp_table[ep - 1].type == USBDEVFS_URB_TYPE_ISO;

}

static int is_halted(USBHostDevice *s, int ep)

{

    return s->endp_table[ep - 1].halted;

}

static void clear_halt(USBHostDevice *s, int ep)

{

    s->endp_table[ep - 1].halted = 0;

}

static void set_halt(USBHostDevice *s, int ep)

{

    s->endp_table[ep - 1].halted = 1;

}

static USBHostDevice *hostdev_list;

static void hostdev_link(USBHostDevice *dev)

{

    dev->next = hostdev_list;

    hostdev_list = dev;

}

static void hostdev_unlink(USBHostDevice *dev)

{

    USBHostDevice *pdev = hostdev_list;

    USBHostDevice **prev = &hostdev_list;

    while (pdev) {

        if (pdev == dev) {

            *prev = dev->next;

            return;

        }

        prev = &pdev->next;

        pdev = pdev->next;

    }

}

static USBHostDevice *hostdev_find(int bus_num, int addr)

{

    USBHostDevice *s = hostdev_list;

    while (s) {

        if (s->bus_num == bus_num && s->addr == addr)

            return s;

        s = s->next;

    }

    return NULL;

}

/* 

 * Async URB state.

 * We always allocate one isoc descriptor even for bulk transfers

 * to simplify allocation and casts. 

 */

typedef struct AsyncURB

{

    struct usbdevfs_urb urb;

    struct usbdevfs_iso_packet_desc isocpd;

    USBPacket     *packet;

    USBHostDevice *hdev;

} AsyncURB;

static AsyncURB *async_alloc(void)

{

    return (AsyncURB *) qemu_mallocz(sizeof(AsyncURB));

}

static void async_free(AsyncURB *aurb)

{

    qemu_free(aurb);

}

static void async_complete(void *opaque)

{

    USBHostDevice *s = opaque;

    AsyncURB *aurb;

    while (1) {

            USBPacket *p;

        int r = ioctl(s->fd, USBDEVFS_REAPURBNDELAY, &aurb);

        if (r < 0) {

            if (errno == EAGAIN)

                return;

            if (errno == ENODEV && !s->closing) {

                printf("husb: device %d.%d disconnected\n", s->bus_num, s->addr);

                usb_device_del_addr(0, s->dev.addr);

                return;

            }

            dprintf("husb: async. reap urb failed errno %d\n", errno);

            return;

        }

        p = aurb->packet;

        dprintf("husb: async completed. aurb %p status %d alen %d\n", 

                aurb, aurb->urb.status, aurb->urb.actual_length);

        if (p) {

            switch (aurb->urb.status) {

            case 0:

                p->len = aurb->urb.actual_length;

                break;

            case -EPIPE:

                set_halt(s, p->devep);

                /* fall through */

            default:

                p->len = USB_RET_NAK;

                break;

            }

            usb_packet_complete(p);

        }

        async_free(aurb);

    }

}

static void async_cancel(USBPacket *unused, void *opaque)

{

    AsyncURB *aurb = opaque;

    USBHostDevice *s = aurb->hdev;

    dprintf("husb: async cancel. aurb %p\n", aurb);

    /* Mark it as dead (see async_complete above) */

    aurb->packet = NULL;

    int r = ioctl(s->fd, USBDEVFS_DISCARDURB, aurb);

    if (r < 0) {

        dprintf("husb: async. discard urb failed errno %d\n", errno);

    }

}

static int usb_host_update_interfaces(USBHostDevice *dev, int configuration)

{

    int dev_descr_len, config_descr_len;

    int interface, nb_interfaces, nb_configurations;

    int ret, i;

    if (configuration == 0) /* address state - ignore */

        return 1;

    i = 0;

    dev_descr_len = dev->descr[0];

    if (dev_descr_len > dev->descr_len)

        goto fail;

    nb_configurations = dev->descr[17];

    i += dev_descr_len;

    while (i < dev->descr_len) {

        dprintf("husb: i is %d, descr_len is %d, dl %d, dt %d\n", i, dev->descr_len,

               dev->descr[i], dev->descr[i+1]);

        if (dev->descr[i+1] != USB_DT_CONFIG) {

            i += dev->descr[i];

            continue;

        }

        config_descr_len = dev->descr[i];

        printf("husb: config #%d need %d\n", dev->descr[i + 5], configuration); 

        if (configuration < 0 || configuration == dev->descr[i + 5])

            break;

        i += config_descr_len;

    }

    if (i >= dev->descr_len) {

        fprintf(stderr, "husb: update iface failed. no matching configuration\n");

        goto fail;

    }

    nb_interfaces = dev->descr[i + 4];

#ifdef USBDEVFS_DISCONNECT

    /* earlier Linux 2.4 do not support that */

    {

        struct usbdevfs_ioctl ctrl;

        for (interface = 0; interface < nb_interfaces; interface++) {

            ctrl.ioctl_code = USBDEVFS_DISCONNECT;

            ctrl.ifno = interface;

            ret = ioctl(dev->fd, USBDEVFS_IOCTL, &ctrl);

            if (ret < 0 && errno != ENODATA) {

                perror("USBDEVFS_DISCONNECT");

                goto fail;

            }

        }

    }

#endif

    /* XXX: only grab if all interfaces are free */

    for (interface = 0; interface < nb_interfaces; interface++) {

        ret = ioctl(dev->fd, USBDEVFS_CLAIMINTERFACE, &interface);

        if (ret < 0) {

            if (errno == EBUSY) {

                printf("husb: update iface. device already grabbed\n");

            } else {

                perror("husb: failed to claim interface");

            }

        fail:

            return 0;

        }

    }

    printf("husb: %d interfaces claimed for configuration %d\n",

           nb_interfaces, configuration);

    return 1;

}

static void usb_host_handle_reset(USBDevice *dev)

{

    USBHostDevice *s = (USBHostDevice *)dev;

    dprintf("husb: reset device %u.%u\n", s->bus_num, s->addr);

    ioctl(s->fd, USBDEVFS_RESET);

    usb_host_update_interfaces(s, s->configuration);

}

static void usb_host_handle_destroy(USBDevice *dev)

{

    USBHostDevice *s = (USBHostDevice *)dev;

    s->closing = 1;

    qemu_set_fd_handler(s->fd, NULL, NULL, NULL);

    hostdev_unlink(s);

    async_complete(s);

    if (s->fd >= 0)

        close(s->fd);

    qemu_free(s);

}

static int usb_linux_update_endp_table(USBHostDevice *s);

static int usb_host_handle_control(USBDevice *dev,

                                   int request,

                                   int value,

                                   int index,

                                   int length,

                                   uint8_t *data)

{

    USBHostDevice *s = (USBHostDevice *)dev;

    struct usb_ctrltransfer ct;

    struct usbdevfs_setinterface si;

    int intf_update_required = 0;

    int ret;

    if (request == (DeviceOutRequest | USB_REQ_SET_ADDRESS)) {

        /* specific SET_ADDRESS support */

        dev->addr = value;

        return 0;

    } else if (request == ((USB_RECIP_INTERFACE << 8) |

                           USB_REQ_SET_INTERFACE)) {

        /* set alternate setting for the interface */

        si.interface = index;

        si.altsetting = value;

        ret = ioctl(s->fd, USBDEVFS_SETINTERFACE, &si);

        usb_linux_update_endp_table(s);

    } else if (request == (DeviceOutRequest | USB_REQ_SET_CONFIGURATION)) {

        dprintf("husb: ctrl set config %d\n", value & 0xff);

        if (s->configuration != (value & 0xff)) {

            s->configuration = (value & 0xff);

            intf_update_required = 1;

        }

        goto do_request;

    } else {

    do_request:

        ct.bRequestType = request >> 8;

        ct.bRequest = request;

        ct.wValue = value;

        ct.wIndex = index;

        ct.wLength = length;

        ct.timeout = 50;

        ct.data = data;

        ret = ioctl(s->fd, USBDEVFS_CONTROL, &ct);

        dprintf("husb: ctrl req 0x%x val 0x%x index %u len %u ret %d\n",

            ct.bRequest, ct.wValue, ct.wIndex, ct.wLength, ret);

    }

    if (ret < 0) {

        switch(errno) {

        case ETIMEDOUT:

            return USB_RET_NAK;

        default:

            return USB_RET_STALL;

        }

    } else {

        if (intf_update_required) {

            dprintf("husb: updating interfaces\n");

            usb_host_update_interfaces(s, value & 0xff);

        }

        return ret;

    }

}

static int usb_host_handle_data(USBDevice *dev, USBPacket *p)

{

    USBHostDevice *s = (USBHostDevice *) dev;

    AsyncURB *aurb;

    struct usbdevfs_urb *urb;

    int ret;

    aurb = async_alloc();

    if (!aurb) {

        dprintf("husb: async malloc failed\n");

        return USB_RET_NAK;

    }

    aurb->hdev   = s;

    aurb->packet = p;

    urb = &aurb->urb;

    if (p->pid == USB_TOKEN_IN)

            urb->endpoint = p->devep | 0x80;

    else

            urb->endpoint = p->devep;

    if (is_halted(s, p->devep)) {

        ret = ioctl(s->fd, USBDEVFS_CLEAR_HALT, &urb->endpoint);

        if (ret < 0) {

            dprintf("husb: failed to clear halt. ep 0x%x errno %d\n", 

                   urb->endpoint, errno);

            return USB_RET_NAK;

        }

        clear_halt(s, p->devep);

    }

    urb->buffer        = p->data;

    urb->buffer_length = p->len;

    if (is_isoc(s, p->devep)) {

        /* Setup ISOC transfer */

        urb->type     = USBDEVFS_URB_TYPE_ISO;

        urb->flags    = USBDEVFS_URB_ISO_ASAP;

        urb->number_of_packets = 1;

        urb->iso_frame_desc[0].length = p->len;

    } else {

        /* Setup bulk transfer */

        urb->type     = USBDEVFS_URB_TYPE_BULK;

    }

    urb->usercontext = s;

    ret = ioctl(s->fd, USBDEVFS_SUBMITURB, urb);

    dprintf("husb: data submit. ep 0x%x len %u aurb %p\n", urb->endpoint, p->len, aurb);

    if (ret < 0) {

        dprintf("husb: submit failed. errno %d\n", errno);

        async_free(aurb);

        switch(errno) {

        case ETIMEDOUT:

            return USB_RET_NAK;

        case EPIPE:

        default:

            return USB_RET_STALL;

        }

    }

    usb_defer_packet(p, async_cancel, aurb);

    return USB_RET_ASYNC;

}

/* returns 1 on problem encountered or 0 for success */

static int usb_linux_update_endp_table(USBHostDevice *s)

{

    uint8_t *descriptors;

    uint8_t devep, type, configuration, alt_interface;

    struct usb_ctrltransfer ct;

    int interface, ret, length, i;

    ct.bRequestType = USB_DIR_IN;

    ct.bRequest = USB_REQ_GET_CONFIGURATION;

    ct.wValue = 0;

    ct.wIndex = 0;

    ct.wLength = 1;

    ct.data = &configuration;

    ct.timeout = 50;

    ret = ioctl(s->fd, USBDEVFS_CONTROL, &ct);

    if (ret < 0) {

        perror("usb_linux_update_endp_table");

        return 1;

    }

    /* in address state */

    if (configuration == 0)

        return 1;

    /* get the desired configuration, interface, and endpoint descriptors

     * from device description */

    descriptors = &s->descr[18];

    length = s->descr_len - 18;

    i = 0;

    if (descriptors[i + 1] != USB_DT_CONFIG ||

        descriptors[i + 5] != configuration) {

        dprintf("invalid descriptor data - configuration\n");

        return 1;

    }

    i += descriptors[i];

    while (i < length) {

        if (descriptors[i + 1] != USB_DT_INTERFACE ||

            (descriptors[i + 1] == USB_DT_INTERFACE &&

             descriptors[i + 4] == 0)) {

            i += descriptors[i];

            continue;

        }

        interface = descriptors[i + 2];

        ct.bRequestType = USB_DIR_IN | USB_RECIP_INTERFACE;

        ct.bRequest = USB_REQ_GET_INTERFACE;

        ct.wValue = 0;

        ct.wIndex = interface;

        ct.wLength = 1;

        ct.data = &alt_interface;

        ct.timeout = 50;

        ret = ioctl(s->fd, USBDEVFS_CONTROL, &ct);

        if (ret < 0) {

            perror("usb_linux_update_endp_table");

            return 1;

        }

        /* the current interface descriptor is the active interface

         * and has endpoints */

        if (descriptors[i + 3] != alt_interface) {

            i += descriptors[i];

            continue;

        }

        /* advance to the endpoints */

        while (i < length && descriptors[i +1] != USB_DT_ENDPOINT)

            i += descriptors[i];

        if (i >= length)

            break;

        while (i < length) {

            if (descriptors[i + 1] != USB_DT_ENDPOINT)

                break;

            devep = descriptors[i + 2];

            switch (descriptors[i + 3] & 0x3) {

            case 0x00:

                type = USBDEVFS_URB_TYPE_CONTROL;

                break;

            case 0x01:

                type = USBDEVFS_URB_TYPE_ISO;

                break;

            case 0x02:

                type = USBDEVFS_URB_TYPE_BULK;

                break;

            case 0x03:

                type = USBDEVFS_URB_TYPE_INTERRUPT;

                break;

            default:

                dprintf("usb_host: malformed endpoint type\n");

                type = USBDEVFS_URB_TYPE_BULK;

            }

            s->endp_table[(devep & 0xf) - 1].type = type;

            s->endp_table[(devep & 0xf) - 1].halted = 0;

            i += descriptors[i];

        }

    }

    return 0;

}

static USBDevice *usb_host_device_open_addr(int bus_num, int addr, const char *prod_name)

{

    int fd = -1, ret;

    USBHostDevice *dev = NULL;

    struct usbdevfs_connectinfo ci;

    char buf[1024];

    dev = qemu_mallocz(sizeof(USBHostDevice));

    if (!dev)

        goto fail;

    dev->bus_num = bus_num;

    dev->addr = addr;

    printf("husb: open device %d.%d\n", bus_num, addr);

    snprintf(buf, sizeof(buf), USBDEVFS_PATH "/%03d/%03d",

             bus_num, addr);

    fd = open(buf, O_RDWR | O_NONBLOCK);

    if (fd < 0) {

        perror(buf);

        goto fail;

    }

    /* read the device description */

    dev->descr_len = read(fd, dev->descr, sizeof(dev->descr));

    if (dev->descr_len <= 0) {

        perror("husb: reading device data failed");

        goto fail;

    }

#ifdef DEBUG

    {

        int x;

        printf("=== begin dumping device descriptor data ===\n");

        for (x = 0; x < dev->descr_len; x++)

            printf("%02x ", dev->descr[x]);

        printf("\n=== end dumping device descriptor data ===\n");

    }

#endif

    dev->fd = fd;

    dev->configuration = 1;

    /* XXX - do something about initial configuration */

    if (!usb_host_update_interfaces(dev, -1))

        goto fail;

    ret = ioctl(fd, USBDEVFS_CONNECTINFO, &ci);

    if (ret < 0) {

        perror("usb_host_device_open: USBDEVFS_CONNECTINFO");

        goto fail;

    }

    printf("husb: grabbed usb device %d.%d\n", bus_num, addr);

    ret = usb_linux_update_endp_table(dev);

    if (ret)

        goto fail;

    if (ci.slow)

        dev->dev.speed = USB_SPEED_LOW;

    else

        dev->dev.speed = USB_SPEED_HIGH;

    dev->dev.handle_packet = usb_generic_handle_packet;

    dev->dev.handle_reset = usb_host_handle_reset;

    dev->dev.handle_control = usb_host_handle_control;

    dev->dev.handle_data = usb_host_handle_data;

    dev->dev.handle_destroy = usb_host_handle_destroy;

    if (!prod_name || prod_name[0] == '\0')

        snprintf(dev->dev.devname, sizeof(dev->dev.devname),

                 "host:%d.%d", bus_num, addr);

    else

        pstrcpy(dev->dev.devname, sizeof(dev->dev.devname),

                prod_name);

    /* USB devio uses 'write' flag to check for async completions */

    qemu_set_fd_handler(dev->fd, NULL, async_complete, dev);

    hostdev_link(dev);

    return (USBDevice *) dev;

fail:

    if (dev)

        qemu_free(dev);

    close(fd);

    return NULL;

}

USBDevice *usb_host_device_open(const char *devname)

{

    int bus_num, addr;

    char product_name[PRODUCT_NAME_SZ];

    if (usb_host_find_device(&bus_num, &addr,

                             product_name, sizeof(product_name),

                             devname) < 0)

        return NULL;

     if (hostdev_find(bus_num, addr)) {

        term_printf("husb: host usb device %d.%d is already open\n", bus_num, addr);

        return NULL;

     }

    return usb_host_device_open_addr(bus_num, addr, product_name);

}

static int get_tag_value(char *buf, int buf_size,

                         const char *str, const char *tag,

                         const char *stopchars)

{

    const char *p;

    char *q;

    p = strstr(str, tag);

    if (!p)

        return -1;

    p += strlen(tag);

    while (isspace(*p))

        p++;

    q = buf;

    while (*p != '\0' && !strchr(stopchars, *p)) {

        if ((q - buf) < (buf_size - 1))

            *q++ = *p;

        p++;

    }

    *q = '\0';

    return q - buf;

}

static int usb_host_scan(void *opaque, USBScanFunc *func)

{

    FILE *f;

    char line[1024];

    char buf[1024];

    int bus_num, addr, speed, device_count, class_id, product_id, vendor_id;

    int ret;

    char product_name[512];

    f = fopen(USBDEVFS_PATH "/devices", "r");

    if (!f) {

        term_printf("husb: could not open %s\n", USBDEVFS_PATH "/devices");

        return 0;

    }

    device_count = 0;

    bus_num = addr = speed = class_id = product_id = vendor_id = 0;

    ret = 0;

    for(;;) {

        if (fgets(line, sizeof(line), f) == NULL)

            break;

        if (strlen(line) > 0)

            line[strlen(line) - 1] = '\0';

        if (line[0] == 'T' && line[1] == ':') {

            if (device_count && (vendor_id || product_id)) {

                /* New device.  Add the previously discovered device.  */

                ret = func(opaque, bus_num, addr, class_id, vendor_id,

                           product_id, product_name, speed);

                if (ret)

                    goto the_end;

            }

            if (get_tag_value(buf, sizeof(buf), line, "Bus=", " ") < 0)

                goto fail;

            bus_num = atoi(buf);

            if (get_tag_value(buf, sizeof(buf), line, "Dev#=", " ") < 0)

                goto fail;

            addr = atoi(buf);

            if (get_tag_value(buf, sizeof(buf), line, "Spd=", " ") < 0)

                goto fail;

            if (!strcmp(buf, "480"))

                speed = USB_SPEED_HIGH;

            else if (!strcmp(buf, "1.5"))

                speed = USB_SPEED_LOW;

            else

                speed = USB_SPEED_FULL;

            product_name[0] = '\0';

            class_id = 0xff;

            device_count++;

            product_id = 0;

            vendor_id = 0;

        } else if (line[0] == 'P' && line[1] == ':') {

            if (get_tag_value(buf, sizeof(buf), line, "Vendor=", " ") < 0)

                goto fail;

            vendor_id = strtoul(buf, NULL, 16);

            if (get_tag_value(buf, sizeof(buf), line, "ProdID=", " ") < 0)

                goto fail;

            product_id = strtoul(buf, NULL, 16);

        } else if (line[0] == 'S' && line[1] == ':') {

            if (get_tag_value(buf, sizeof(buf), line, "Product=", "") < 0)

                goto fail;

            pstrcpy(product_name, sizeof(product_name), buf);

        } else if (line[0] == 'D' && line[1] == ':') {

            if (get_tag_value(buf, sizeof(buf), line, "Cls=", " (") < 0)

                goto fail;

            class_id = strtoul(buf, NULL, 16);

        }

    fail: ;

    }

    if (device_count && (vendor_id || product_id)) {

        /* Add the last device.  */

        ret = func(opaque, bus_num, addr, class_id, vendor_id,

                   product_id, product_name, speed);

    }

 the_end:

    fclose(f);

    return ret;

}

struct USBAutoFilter {

    struct USBAutoFilter *next;

    int bus_num;

    int addr;

    int vendor_id;

    int product_id;

};

static QEMUTimer *usb_auto_timer;

static struct USBAutoFilter *usb_auto_filter;

static int usb_host_auto_scan(void *opaque, int bus_num, int addr,

                     int class_id, int vendor_id, int product_id,

                     const char *product_name, int speed)

{

    struct USBAutoFilter *f;

    struct USBDevice *dev;

    /* Ignore hubs */

    if (class_id == 9)

        return 0;

    for (f = usb_auto_filter; f; f = f->next) {

        if (f->bus_num >= 0 && f->bus_num != bus_num)

            continue;

        if (f->addr >= 0 && f->addr != addr)

            continue;

        if (f->vendor_id >= 0 && f->vendor_id != vendor_id)

            continue;

        if (f->product_id >= 0 && f->product_id != product_id)

            continue;

        /* We got a match */

        /* Allredy attached ? */

        if (hostdev_find(bus_num, addr))

            return 0;

        dprintf("husb: auto open: bus_num %d addr %d\n", bus_num, addr);

        dev = usb_host_device_open_addr(bus_num, addr, product_name);

        if (dev)

            usb_device_add_dev(dev);

    }

    return 0;

}

static void usb_host_auto_timer(void *unused)

{

    usb_host_scan(NULL, usb_host_auto_scan);

    qemu_mod_timer(usb_auto_timer, qemu_get_clock(rt_clock) + 2000);

}

/*

 * Add autoconnect filter

 * -1 means 'any' (device, vendor, etc)

 */

static void usb_host_auto_add(int bus_num, int addr, int vendor_id, int product_id)

{

    struct USBAutoFilter *f = qemu_mallocz(sizeof(*f));

    if (!f) {

        fprintf(stderr, "husb: failed to allocate auto filter\n");

        return;

    }

    f->bus_num = bus_num;

    f->addr    = addr;

    f->vendor_id  = vendor_id;

    f->product_id = product_id;

    if (!usb_auto_filter) {

        /*

         * First entry. Init and start the monitor.

         * Right now we're using timer to check for new devices.

         * If this turns out to be too expensive we can move that into a 

         * separate thread.

         */

        usb_auto_timer = qemu_new_timer(rt_clock, usb_host_auto_timer, NULL);

        if (!usb_auto_timer) {