usb-linux.c 26.6 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974
/*
 * Linux host USB redirector
 *
 * Copyright (c) 2005 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 "qemu-common.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
//#define DEBUG_ISOCH
//#define USE_ASYNCIO

#define USBDEVFS_PATH "/proc/bus/usb"
#define PRODUCT_NAME_SZ 32
#define SIG_ISOCOMPLETE (SIGRTMIN+7)
#define MAX_ENDPOINTS 16

struct sigaction sigact;

/* endpoint association data */
struct endp_data {
    uint8_t type;
};

/* FIXME: move USBPacket to PendingURB */
typedef struct USBHostDevice {
    USBDevice dev;
    int fd;
    int pipe_fds[2];
    USBPacket *packet;
    struct endp_data endp_table[MAX_ENDPOINTS];
    int configuration;
    uint8_t descr[1024];
    int descr_len;
    int urbs_ready;
} USBHostDevice;

typedef struct PendingURB {
    struct usbdevfs_urb *urb;
    int status;
    struct PendingURB *next;
} PendingURB;

static PendingURB *pending_urbs = NULL;

static int add_pending_urb(struct usbdevfs_urb *urb)
{
    PendingURB *purb = qemu_mallocz(sizeof(PendingURB));
    if (purb) {
        purb->urb = urb;
        purb->status = 0;
        purb->next = pending_urbs;
        pending_urbs = purb;
        return 1;
    }
    return 0;
}

static int del_pending_urb(struct usbdevfs_urb *urb)
{
    PendingURB *purb = pending_urbs;
    PendingURB *prev = NULL;

    while (purb && purb->urb != urb) {
        prev = purb;
        purb = purb->next;
    }

    if (purb && purb->urb == urb) {
        if (prev) {
            prev->next = purb->next;
        } else {
            pending_urbs = purb->next;
        }
        qemu_free(purb);
        return 1;
    }
    return 0;
}

#ifdef USE_ASYNCIO
static PendingURB *get_pending_urb(struct usbdevfs_urb *urb)
{
    PendingURB *purb = pending_urbs;

    while (purb && purb->urb != urb) {
        purb = purb->next;
    }

    if (purb && purb->urb == urb) {
        return purb;
    }
    return NULL;
}
#endif

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) {
#ifdef DEBUG
        printf("i is %d, descr_len is %d, dl %d, dt %d\n", i, dev->descr_len,
               dev->descr[i], dev->descr[i+1]);
#endif
        if (dev->descr[i+1] != USB_DT_CONFIG) {
            i += dev->descr[i];
            continue;
        }
        config_descr_len = dev->descr[i];

        if (configuration == dev->descr[i + 5])
            break;

        i += config_descr_len;
    }

    if (i >= dev->descr_len) {
        printf("usb_host: error - device has 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) {
                fprintf(stderr,
                        "usb_host: warning - device already grabbed\n");
            } else {
                perror("USBDEVFS_CLAIMINTERFACE");
            }
        fail:
            return 0;
        }
    }

#ifdef DEBUG
    printf("usb_host: %d interfaces claimed for configuration %d\n",
           nb_interfaces, configuration);
#endif

    return 1;
}

static void usb_host_handle_reset(USBDevice *dev)
{
#if 0
    USBHostDevice *s = (USBHostDevice *)dev;
    /* USBDEVFS_RESET, but not the first time as it has already be
       done by the host OS */
    ioctl(s->fd, USBDEVFS_RESET);
#endif
}

static void usb_host_handle_destroy(USBDevice *dev)
{
    USBHostDevice *s = (USBHostDevice *)dev;

    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)) {
#ifdef DEBUG
        printf("usb_host_handle_control: SET_CONFIGURATION request - "
               "config %d\n", value & 0xff);
#endif
        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);
    }

    if (ret < 0) {
        switch(errno) {
        case ETIMEDOUT:
            return USB_RET_NAK;
        default:
            return USB_RET_STALL;
        }
    } else {
        if (intf_update_required) {
#ifdef DEBUG
            printf("usb_host_handle_control: updating interfaces\n");
#endif
            usb_host_update_interfaces(s, value & 0xff);
        }
        return ret;
    }
}

static int usb_host_handle_isoch(USBDevice *dev, USBPacket *p);

static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
{
    USBHostDevice *s = (USBHostDevice *)dev;
    struct usbdevfs_bulktransfer bt;
    int ret;
    uint8_t devep = p->devep;

    if (s->endp_table[p->devep - 1].type == USBDEVFS_URB_TYPE_ISO) {
        return usb_host_handle_isoch(dev, p);
    }

    /* XXX: optimize and handle all data types by looking at the
       config descriptor */
    if (p->pid == USB_TOKEN_IN)
        devep |= 0x80;
    bt.ep = devep;
    bt.len = p->len;
    bt.timeout = 50;
    bt.data = p->data;
    ret = ioctl(s->fd, USBDEVFS_BULK, &bt);
    if (ret < 0) {
        switch(errno) {
        case ETIMEDOUT:
            return USB_RET_NAK;
        case EPIPE:
        default:
#ifdef DEBUG
            printf("handle_data: errno=%d\n", errno);
#endif
            return USB_RET_STALL;
        }
    } else {
        return ret;
    }
}

#ifdef USE_ASYNCIO
static void urb_completion_pipe_read(void *opaque)
{
    USBHostDevice *s = opaque;
    USBPacket *p = s->packet;
    PendingURB *pending_urb = NULL;
    struct usbdevfs_urb *purb = NULL;
    int len, ret;

    len = read(s->pipe_fds[0], &pending_urb, sizeof(pending_urb));
    if (len != sizeof(pending_urb)) {
        printf("urb_completion: error reading pending_urb, len=%d\n", len);
        return;
    }

    /* FIXME: handle pending_urb->status */
    del_pending_urb(pending_urb->urb);

    if (!p) {
        s->urbs_ready++;
        return;
    }

    ret = ioctl(s->fd, USBDEVFS_REAPURBNDELAY, &purb);
    if (ret < 0) {
        printf("urb_completion: REAPURBNDELAY ioctl=%d errno=%d\n",
               ret, errno);
        return;
    }

#ifdef DEBUG_ISOCH
    if (purb == pending_urb->urb) {
        printf("urb_completion: urb mismatch reaped=%p pending=%p\n",
               purb, urb);
    }
#endif

    p->len = purb->actual_length;
    usb_packet_complete(p);
    qemu_free(purb);
    s->packet = NULL;
}

static void isoch_done(int signum, siginfo_t *info, void *context)
{
    struct usbdevfs_urb *urb = (struct usbdevfs_urb *)info->si_addr;
    USBHostDevice *s = (USBHostDevice *)urb->usercontext;
    PendingURB *purb;

    if (info->si_code != SI_ASYNCIO ||
        info->si_signo != SIG_ISOCOMPLETE) {
        return;
    }

    purb = get_pending_urb(urb);
    if (purb) {
        purb->status = info->si_errno;
        write(s->pipe_fds[1], &purb, sizeof(purb));
    }
}
#endif

static int usb_host_handle_isoch(USBDevice *dev, USBPacket *p)
{
    USBHostDevice *s = (USBHostDevice *)dev;
    struct usbdevfs_urb *urb, *purb = NULL;
    int ret;
    uint8_t devep = p->devep;

    if (p->pid == USB_TOKEN_IN)
        devep |= 0x80;

    urb = qemu_mallocz(sizeof(struct usbdevfs_urb) +
                       sizeof(struct usbdevfs_iso_packet_desc));
    if (!urb) {
        printf("usb_host_handle_isoch: malloc failed\n");
        return 0;
    }

    urb->type = USBDEVFS_URB_TYPE_ISO;
    urb->endpoint = devep;
    urb->status = 0;
    urb->flags = USBDEVFS_URB_ISO_ASAP;
    urb->buffer = p->data;
    urb->buffer_length = p->len;
    urb->actual_length = 0;
    urb->start_frame = 0;
    urb->error_count = 0;
#ifdef USE_ASYNCIO
    urb->signr = SIG_ISOCOMPLETE;
#else
    urb->signr = 0;
#endif
    urb->usercontext = s;
    urb->number_of_packets = 1;
    urb->iso_frame_desc[0].length = p->len;
    urb->iso_frame_desc[0].actual_length = 0;
    urb->iso_frame_desc[0].status = 0;
    ret = ioctl(s->fd, USBDEVFS_SUBMITURB, urb);
    if (ret == 0) {
        if (!add_pending_urb(urb)) {
            printf("usb_host_handle_isoch: add_pending_urb failed %p\n", urb);
        }
    } else {
        printf("usb_host_handle_isoch: SUBMITURB ioctl=%d errno=%d\n",
               ret, errno);
        qemu_free(urb);
        switch(errno) {
        case ETIMEDOUT:
            return USB_RET_NAK;
        case EPIPE:
        default:
            return USB_RET_STALL;
        }
    }
#ifdef USE_ASYNCIO
    /* FIXME: handle urbs_ready together with sync io
     * workaround for injecting the signaled urbs into current frame */
    if (s->urbs_ready > 0) {
        ret = ioctl(s->fd, USBDEVFS_REAPURBNDELAY, &purb);
        if (ret == 0) {
            ret = purb->actual_length;
            qemu_free(purb);
            s->urbs_ready--;
        }
        return ret;
    }
    s->packet = p;
    return USB_RET_ASYNC;
#else
    ret = ioctl(s->fd, USBDEVFS_REAPURBNDELAY, &purb);
    if (ret == 0) {
        if (del_pending_urb(purb)) {
            ret = purb->actual_length;
            qemu_free(purb);
        } else {
            printf("usb_host_handle_isoch: del_pending_urb failed %p\n", purb);
        }
    } else {
#ifdef DEBUG_ISOCH
        printf("usb_host_handle_isoch: REAPURBNDELAY ioctl=%d errno=%d\n",
               ret, errno);
#endif
    }
    return ret;
#endif
}

/* 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) {
        printf("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:
                printf("usb_host: malformed endpoint type\n");
                type = USBDEVFS_URB_TYPE_BULK;
            }
            s->endp_table[(devep & 0xf) - 1].type = type;

            i += descriptors[i];
        }
    }
    return 0;
}

/* XXX: exclude high speed devices or implement EHCI */
USBDevice *usb_host_device_open(const char *devname)
{
    int fd = -1, ret;
    USBHostDevice *dev = NULL;
    struct usbdevfs_connectinfo ci;
    char buf[1024];
    int bus_num, addr;
    char product_name[PRODUCT_NAME_SZ];

    dev = qemu_mallocz(sizeof(USBHostDevice));
    if (!dev)
        goto fail;

#ifdef DEBUG_ISOCH
    printf("usb_host_device_open %s\n", devname);
#endif
    if (usb_host_find_device(&bus_num, &addr,
                             product_name, sizeof(product_name),
                             devname) < 0)
        return NULL;

    snprintf(buf, sizeof(buf), USBDEVFS_PATH "/%03d/%03d",
             bus_num, addr);
    fd = open(buf, O_RDWR | O_NONBLOCK);
    if (fd < 0) {
        perror(buf);
        return NULL;
    }

    /* read the device description */
    dev->descr_len = read(fd, dev->descr, sizeof(dev->descr));
    if (dev->descr_len <= 0) {
        perror("usb_host_device_open: 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;
    }

#ifdef DEBUG
    printf("host USB device %d.%d grabbed\n", bus_num, addr);
#endif

    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 (product_name[0] == '\0')
        snprintf(dev->dev.devname, sizeof(dev->dev.devname),
                 "host:%s", devname);
    else
        pstrcpy(dev->dev.devname, sizeof(dev->dev.devname),
                product_name);

#ifdef USE_ASYNCIO
    /* set up the signal handlers */
    sigemptyset(&sigact.sa_mask);
    sigact.sa_sigaction = isoch_done;
    sigact.sa_flags = SA_SIGINFO;
    sigact.sa_restorer = 0;
    ret = sigaction(SIG_ISOCOMPLETE, &sigact, NULL);
    if (ret < 0) {
        perror("usb_host_device_open: sigaction failed");
        goto fail;
    }

    if (pipe(dev->pipe_fds) < 0) {
        perror("usb_host_device_open: pipe creation failed");
        goto fail;
    }
    fcntl(dev->pipe_fds[0], F_SETFL, O_NONBLOCK | O_ASYNC);
    fcntl(dev->pipe_fds[1], F_SETFL, O_NONBLOCK);
    qemu_set_fd_handler(dev->pipe_fds[0], urb_completion_pipe_read, NULL, dev);
#endif
    dev->urbs_ready = 0;
    return (USBDevice *)dev;
fail:
    if (dev)
        qemu_free(dev);
    close(fd);
    return NULL;
}

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("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;
}

typedef struct FindDeviceState {
    int vendor_id;
    int product_id;
    int bus_num;
    int addr;
    char product_name[PRODUCT_NAME_SZ];
} FindDeviceState;

static int usb_host_find_device_scan(void *opaque, int bus_num, int addr,
                                     int class_id,
                                     int vendor_id, int product_id,
                                     const char *product_name, int speed)
{
    FindDeviceState *s = opaque;
    if ((vendor_id == s->vendor_id &&
        product_id == s->product_id) ||
        (bus_num == s->bus_num &&
        addr == s->addr)) {
        pstrcpy(s->product_name, PRODUCT_NAME_SZ, product_name);
        s->bus_num = bus_num;
        s->addr = addr;
        return 1;
    } else {
        return 0;
    }
}

/* the syntax is :
   'bus.addr' (decimal numbers) or
   'vendor_id:product_id' (hexa numbers) */
static int usb_host_find_device(int *pbus_num, int *paddr,
                                char *product_name, int product_name_size,
                                const char *devname)
{
    const char *p;
    int ret;
    FindDeviceState fs;

    p = strchr(devname, '.');
    if (p) {
        *pbus_num = strtoul(devname, NULL, 0);
        *paddr = strtoul(p + 1, NULL, 0);
        fs.bus_num = *pbus_num;
        fs.addr = *paddr;
        ret = usb_host_scan(&fs, usb_host_find_device_scan);
        if (ret)
            pstrcpy(product_name, product_name_size, fs.product_name);
        return 0;
    }
    p = strchr(devname, ':');
    if (p) {
        fs.vendor_id = strtoul(devname, NULL, 16);
        fs.product_id = strtoul(p + 1, NULL, 16);
        ret = usb_host_scan(&fs, usb_host_find_device_scan);
        if (ret) {
            *pbus_num = fs.bus_num;
            *paddr = fs.addr;
            pstrcpy(product_name, product_name_size, fs.product_name);
            return 0;
        }
    }
    return -1;
}

/**********************/
/* USB host device info */

struct usb_class_info {
    int class;
    const char *class_name;
};

static const struct usb_class_info usb_class_info[] = {
    { USB_CLASS_AUDIO, "Audio"},
    { USB_CLASS_COMM, "Communication"},
    { USB_CLASS_HID, "HID"},
    { USB_CLASS_HUB, "Hub" },
    { USB_CLASS_PHYSICAL, "Physical" },
    { USB_CLASS_PRINTER, "Printer" },
    { USB_CLASS_MASS_STORAGE, "Storage" },
    { USB_CLASS_CDC_DATA, "Data" },
    { USB_CLASS_APP_SPEC, "Application Specific" },
    { USB_CLASS_VENDOR_SPEC, "Vendor Specific" },
    { USB_CLASS_STILL_IMAGE, "Still Image" },
    { USB_CLASS_CSCID, "Smart Card" },
    { USB_CLASS_CONTENT_SEC, "Content Security" },
    { -1, NULL }
};

static const char *usb_class_str(uint8_t class)
{
    const struct usb_class_info *p;
    for(p = usb_class_info; p->class != -1; p++) {
        if (p->class == class)
            break;
    }
    return p->class_name;
}

static void usb_info_device(int bus_num, int addr, int class_id,
                            int vendor_id, int product_id,
                            const char *product_name,
                            int speed)
{
    const char *class_str, *speed_str;

    switch(speed) {
    case USB_SPEED_LOW:
        speed_str = "1.5";
        break;
    case USB_SPEED_FULL:
        speed_str = "12";
        break;
    case USB_SPEED_HIGH:
        speed_str = "480";
        break;
    default:
        speed_str = "?";
        break;
    }

    term_printf("  Device %d.%d, speed %s Mb/s\n",
                bus_num, addr, speed_str);
    class_str = usb_class_str(class_id);
    if (class_str)
        term_printf("    %s:", class_str);
    else
        term_printf("    Class %02x:", class_id);
    term_printf(" USB device %04x:%04x", vendor_id, product_id);
    if (product_name[0] != '\0')
        term_printf(", %s", product_name);
    term_printf("\n");
}

static int usb_host_info_device(void *opaque, int bus_num, int addr,
                                int class_id,
                                int vendor_id, int product_id,
                                const char *product_name,
                                int speed)
{
    usb_info_device(bus_num, addr, class_id, vendor_id, product_id,
                    product_name, speed);
    return 0;
}

void usb_host_info(void)
{
    usb_host_scan(NULL, usb_host_info_device);
}

#else

void usb_host_info(void)
{
    term_printf("USB host devices not supported\n");
}

/* XXX: modify configure to compile the right host driver */
USBDevice *usb_host_device_open(const char *devname)
{
    return NULL;
}

#endif