symbian-qemu-0.9.1-12/qemu-symbian-svp/usb-linux.c
changeset 1 2fb8b9db1c86
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/qemu-symbian-svp/usb-linux.c	Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,1698 @@
+/*
+ * Linux host USB redirector
+ *
+ * Copyright (c) 2005 Fabrice Bellard
+ *
+ * Copyright (c) 2008 Max Krasnyansky
+ *      Support for host device auto connect & disconnect
+ *      Major rewrite to support fully async operation
+ *
+ * Copyright 2008 TJ <linux@tjworld.net>
+ *      Added flexible support for /dev/bus/usb /sys/bus/usb/devices in addition
+ *      to the legacy /proc/bus/usb USB device discovery and handling
+ *
+ * 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 "console.h"
+
+#include <dirent.h>
+#include <sys/ioctl.h>
+#include <signal.h>
+
+#include <linux/usbdevice_fs.h>
+#include <linux/version.h>
+#include "hw/usb.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;
+};
+
+struct usb_ctrlrequest {
+    uint8_t bRequestType;
+    uint8_t bRequest;
+    uint16_t wValue;
+    uint16_t wIndex;
+    uint16_t wLength;
+};
+
+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 USBDBG_DEVOPENED "husb: opened %s/devices\n"
+
+#define USBPROCBUS_PATH "/proc/bus/usb"
+#define PRODUCT_NAME_SZ 32
+#define MAX_ENDPOINTS 16
+#define USBDEVBUS_PATH "/dev/bus/usb"
+#define USBSYSBUS_PATH "/sys/bus/usb"
+
+static char *usb_host_device_path;
+
+#define USB_FS_NONE 0
+#define USB_FS_PROC 1
+#define USB_FS_DEV 2
+#define USB_FS_SYS 3
+
+static int usb_fs_type;
+
+/* endpoint association data */
+struct endp_data {
+    uint8_t type;
+    uint8_t halted;
+};
+
+enum {
+    CTRL_STATE_IDLE = 0,
+    CTRL_STATE_SETUP,
+    CTRL_STATE_DATA,
+    CTRL_STATE_ACK
+};
+
+/*
+ * Control transfer state.
+ * Note that 'buffer' _must_ follow 'req' field because 
+ * we need contigious buffer when we submit control URB.
+ */ 
+struct ctrl_struct {
+    uint16_t len;
+    uint16_t offset;
+    uint8_t  state;
+    struct   usb_ctrlrequest req;
+    uint8_t  buffer[1024];
+};
+
+typedef struct USBHostDevice {
+    USBDevice dev;
+    int       fd;
+
+    uint8_t   descr[1024];
+    int       descr_len;
+    int       configuration;
+    int       ninterfaces;
+    int       closing;
+
+    struct ctrl_struct ctrl;
+    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_ctrl(USBHostDevice *s, USBPacket *p)
+{
+    switch(s->ctrl.state) {
+    case CTRL_STATE_SETUP:
+        if (p->len < s->ctrl.len)
+            s->ctrl.len = p->len;
+        s->ctrl.state = CTRL_STATE_DATA;
+        p->len = 8;
+        break;
+
+    case CTRL_STATE_ACK:
+        s->ctrl.state = CTRL_STATE_IDLE;
+        p->len = 0;
+        break;
+
+    default:
+        break;
+    }
+}
+
+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;
+                if (aurb->urb.type == USBDEVFS_URB_TYPE_CONTROL)
+                    async_complete_ctrl(s, p);
+                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_claim_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;
+
+    dprintf("husb: claiming interfaces. config %d\n", configuration);
+
+    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]) {
+            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);
+
+    dev->ninterfaces   = nb_interfaces;
+    dev->configuration = configuration;
+    return 1;
+}
+
+static int usb_host_release_interfaces(USBHostDevice *s)
+{
+    int ret, i;
+
+    dprintf("husb: releasing interfaces\n");
+
+    for (i = 0; i < s->ninterfaces; i++) {
+        ret = ioctl(s->fd, USBDEVFS_RELEASEINTERFACE, &i);
+        if (ret < 0) {
+            perror("husb: failed to release interface");
+            return 0;
+        }
+    }
+
+    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_claim_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_data(USBHostDevice *s, USBPacket *p)
+{
+    struct usbdevfs_urb *urb;
+    AsyncURB *aurb;
+    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;
+}
+
+static int ctrl_error(void)
+{
+    if (errno == ETIMEDOUT)
+        return USB_RET_NAK;
+    else 
+        return USB_RET_STALL;
+}
+
+static int usb_host_set_address(USBHostDevice *s, int addr)
+{
+    dprintf("husb: ctrl set addr %u\n", addr);
+    s->dev.addr = addr;
+    return 0;
+}
+
+static int usb_host_set_config(USBHostDevice *s, int config)
+{
+    usb_host_release_interfaces(s);
+
+    int ret = ioctl(s->fd, USBDEVFS_SETCONFIGURATION, &config);
+ 
+    dprintf("husb: ctrl set config %d ret %d errno %d\n", config, ret, errno);
+    
+    if (ret < 0)
+        return ctrl_error();
+ 
+    usb_host_claim_interfaces(s, config);
+    return 0;
+}
+
+static int usb_host_set_interface(USBHostDevice *s, int iface, int alt)
+{
+    struct usbdevfs_setinterface si;
+    int ret;
+
+    si.interface  = iface;
+    si.altsetting = alt;
+    ret = ioctl(s->fd, USBDEVFS_SETINTERFACE, &si);
+    
+    dprintf("husb: ctrl set iface %d altset %d ret %d errno %d\n", 
+    	iface, alt, ret, errno);
+    
+    if (ret < 0)
+        return ctrl_error();
+
+    usb_linux_update_endp_table(s);
+    return 0;
+}
+
+static int usb_host_handle_control(USBHostDevice *s, USBPacket *p)
+{
+    struct usbdevfs_urb *urb;
+    AsyncURB *aurb;
+    int ret, value, index;
+
+    /* 
+     * Process certain standard device requests.
+     * These are infrequent and are processed synchronously.
+     */
+    value = le16_to_cpu(s->ctrl.req.wValue);
+    index = le16_to_cpu(s->ctrl.req.wIndex);
+
+    dprintf("husb: ctrl type 0x%x req 0x%x val 0x%x index %u len %u\n",
+        s->ctrl.req.bRequestType, s->ctrl.req.bRequest, value, index, 
+        s->ctrl.len);
+
+    if (s->ctrl.req.bRequestType == 0) {
+        switch (s->ctrl.req.bRequest) {
+        case USB_REQ_SET_ADDRESS:
+            return usb_host_set_address(s, value);
+
+        case USB_REQ_SET_CONFIGURATION:
+            return usb_host_set_config(s, value & 0xff);
+        }
+    }
+
+    if (s->ctrl.req.bRequestType == 1 &&
+                  s->ctrl.req.bRequest == USB_REQ_SET_INTERFACE)
+        return usb_host_set_interface(s, index, value);
+
+    /* The rest are asynchronous */
+
+    aurb = async_alloc();
+    if (!aurb) {
+        dprintf("husb: async malloc failed\n");
+        return USB_RET_NAK;
+    }
+    aurb->hdev   = s;
+    aurb->packet = p;
+
+    /* 
+     * Setup ctrl transfer.
+     *
+     * s->ctrl is layed out such that data buffer immediately follows
+     * 'req' struct which is exactly what usbdevfs expects.
+     */ 
+    urb = &aurb->urb;
+
+    urb->type     = USBDEVFS_URB_TYPE_CONTROL;
+    urb->endpoint = p->devep;
+
+    urb->buffer        = &s->ctrl.req;
+    urb->buffer_length = 8 + s->ctrl.len;
+
+    urb->usercontext = s;
+
+    ret = ioctl(s->fd, USBDEVFS_SUBMITURB, urb);
+
+    dprintf("husb: submit ctrl. len %u aurb %p\n", urb->buffer_length, 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;
+}
+
+static int do_token_setup(USBDevice *dev, USBPacket *p)
+{
+    USBHostDevice *s = (USBHostDevice *) dev;
+    int ret = 0;
+
+    if (p->len != 8)
+        return USB_RET_STALL;
+ 
+    memcpy(&s->ctrl.req, p->data, 8);
+    s->ctrl.len    = le16_to_cpu(s->ctrl.req.wLength);
+    s->ctrl.offset = 0;
+    s->ctrl.state  = CTRL_STATE_SETUP;
+
+    if (s->ctrl.req.bRequestType & USB_DIR_IN) {
+        ret = usb_host_handle_control(s, p);
+        if (ret < 0)
+            return ret;
+
+        if (ret < s->ctrl.len)
+            s->ctrl.len = ret;
+        s->ctrl.state = CTRL_STATE_DATA;
+    } else {
+        if (s->ctrl.len == 0)
+            s->ctrl.state = CTRL_STATE_ACK;
+        else
+            s->ctrl.state = CTRL_STATE_DATA;
+    }
+
+    return ret;
+}
+
+static int do_token_in(USBDevice *dev, USBPacket *p)
+{
+    USBHostDevice *s = (USBHostDevice *) dev;
+    int ret = 0;
+
+    if (p->devep != 0)
+        return usb_host_handle_data(s, p);
+
+    switch(s->ctrl.state) {
+    case CTRL_STATE_ACK:
+        if (!(s->ctrl.req.bRequestType & USB_DIR_IN)) {
+            ret = usb_host_handle_control(s, p);
+            if (ret == USB_RET_ASYNC)
+                return USB_RET_ASYNC;
+
+            s->ctrl.state = CTRL_STATE_IDLE;
+            return ret > 0 ? 0 : ret;
+        }
+
+        return 0;
+
+    case CTRL_STATE_DATA:
+        if (s->ctrl.req.bRequestType & USB_DIR_IN) {
+            int len = s->ctrl.len - s->ctrl.offset;
+            if (len > p->len)
+                len = p->len;
+            memcpy(p->data, s->ctrl.buffer + s->ctrl.offset, len);
+            s->ctrl.offset += len;
+            if (s->ctrl.offset >= s->ctrl.len)
+                s->ctrl.state = CTRL_STATE_ACK;
+            return len;
+        }
+
+        s->ctrl.state = CTRL_STATE_IDLE;
+        return USB_RET_STALL;
+
+    default:
+        return USB_RET_STALL;
+    }
+}
+
+static int do_token_out(USBDevice *dev, USBPacket *p)
+{
+    USBHostDevice *s = (USBHostDevice *) dev;
+
+    if (p->devep != 0)
+        return usb_host_handle_data(s, p);
+
+    switch(s->ctrl.state) {
+    case CTRL_STATE_ACK:
+        if (s->ctrl.req.bRequestType & USB_DIR_IN) {
+            s->ctrl.state = CTRL_STATE_IDLE;
+            /* transfer OK */
+        } else {
+            /* ignore additional output */
+        }
+        return 0;
+
+    case CTRL_STATE_DATA:
+        if (!(s->ctrl.req.bRequestType & USB_DIR_IN)) {
+            int len = s->ctrl.len - s->ctrl.offset;
+            if (len > p->len)
+                len = p->len;
+            memcpy(s->ctrl.buffer + s->ctrl.offset, p->data, len);
+            s->ctrl.offset += len;
+            if (s->ctrl.offset >= s->ctrl.len)
+                s->ctrl.state = CTRL_STATE_ACK;
+            return len;
+        }
+
+        s->ctrl.state = CTRL_STATE_IDLE;
+        return USB_RET_STALL;
+
+    default:
+        return USB_RET_STALL;
+    }
+}
+
+/*
+ * Packet handler.
+ * Called by the HC (host controller).
+ *
+ * Returns length of the transaction or one of the USB_RET_XXX codes.
+ */
+static int usb_host_handle_packet(USBDevice *s, USBPacket *p)
+{
+    switch(p->pid) {
+    case USB_MSG_ATTACH:
+        s->state = USB_STATE_ATTACHED;
+        return 0;
+
+    case USB_MSG_DETACH:
+        s->state = USB_STATE_NOTATTACHED;
+        return 0;
+
+    case USB_MSG_RESET:
+        s->remote_wakeup = 0;
+        s->addr = 0;
+        s->state = USB_STATE_DEFAULT;
+        s->handle_reset(s);
+        return 0;
+    }
+
+    /* Rest of the PIDs must match our address */
+    if (s->state < USB_STATE_DEFAULT || p->devaddr != s->addr)
+        return USB_RET_NODEV;
+
+    switch (p->pid) {
+    case USB_TOKEN_SETUP:
+        return do_token_setup(s, p);
+
+    case USB_TOKEN_IN:
+        return do_token_in(s, p);
+
+    case USB_TOKEN_OUT:
+        return do_token_out(s, p);
+ 
+    default:
+        return USB_RET_STALL;
+    }
+}
+
+/* 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);
+
+    if (!usb_host_device_path) {
+        perror("husb: USB Host Device Path not set");
+        goto fail;
+    }
+    snprintf(buf, sizeof(buf), "%s/%03d/%03d", usb_host_device_path,
+             bus_num, addr);
+    fd = open(buf, O_RDWR | O_NONBLOCK);
+    if (fd < 0) {
+        perror(buf);
+        goto fail;
+    }
+    dprintf("husb: opened %s\n", buf);
+
+    /* 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;
+
+    /* 
+     * Initial configuration is -1 which makes us claim first 
+     * available config. We used to start with 1, which does not
+     * always work. I've seen devices where first config starts 
+     * with 2.
+     */
+    if (!usb_host_claim_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_host_handle_packet;
+    dev->dev.handle_reset   = usb_host_handle_reset;
+    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;
+}
+
+static int usb_host_auto_add(const char *spec);
+static int usb_host_auto_del(const char *spec);
+
+USBDevice *usb_host_device_open(const char *devname)
+{
+    int bus_num, addr;
+    char product_name[PRODUCT_NAME_SZ];
+
+    if (strstr(devname, "auto:")) {
+        usb_host_auto_add(devname);
+        return NULL;
+    }
+
+    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);
+}
+
+int usb_host_device_close(const char *devname)
+{
+    char product_name[PRODUCT_NAME_SZ];
+    int bus_num, addr;
+    USBHostDevice *s;
+
+    if (strstr(devname, "auto:"))
+        return usb_host_auto_del(devname);
+
+    if (usb_host_find_device(&bus_num, &addr, product_name, sizeof(product_name),
+                             devname) < 0)
+        return -1;
+ 
+    s = hostdev_find(bus_num, addr);
+    if (s) {
+        usb_device_del_addr(0, s->dev.addr);
+        return 0;
+    }
+
+    return -1;
+}
+ 
+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 (qemu_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;
+}
+
+/*
+ * Use /proc/bus/usb/devices or /dev/bus/usb/devices file to determine
+ * host's USB devices. This is legacy support since many distributions
+ * are moving to /sys/bus/usb
+ */
+static int usb_host_scan_dev(void *opaque, USBScanFunc *func)
+{
+    FILE *f = 0;
+    char line[1024];
+    char buf[1024];
+    int bus_num, addr, speed, device_count, class_id, product_id, vendor_id;
+    char product_name[512];
+    int ret = 0;
+
+    if (!usb_host_device_path) {
+        perror("husb: USB Host Device Path not set");
+        goto the_end;
+    }
+    snprintf(line, sizeof(line), "%s/devices", usb_host_device_path);
+    f = fopen(line, "r");
+    if (!f) {
+        perror("husb: cannot open devices file");
+        goto the_end;
+    }
+
+    device_count = 0;
+    bus_num = addr = speed = class_id = product_id = vendor_id = 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:
+    if (f)
+        fclose(f);
+    return ret;
+}
+
+/*
+ * Read sys file-system device file
+ *
+ * @line address of buffer to put file contents in
+ * @line_size size of line
+ * @device_file path to device file (printf format string)
+ * @device_name device being opened (inserted into device_file)
+ *
+ * @return 0 failed, 1 succeeded ('line' contains data)
+ */
+static int usb_host_read_file(char *line, size_t line_size, const char *device_file, const char *device_name)
+{
+    FILE *f;
+    int ret = 0;
+    char filename[PATH_MAX];
+
+    snprintf(filename, PATH_MAX, device_file, device_name);
+    f = fopen(filename, "r");
+    if (f) {
+        fgets(line, line_size, f);
+        fclose(f);
+        ret = 1;
+    } else {
+        term_printf("husb: could not open %s\n", filename);
+    }
+
+    return ret;
+}
+
+/*
+ * Use /sys/bus/usb/devices/ directory to determine host's USB
+ * devices.
+ *
+ * This code is based on Robert Schiele's original patches posted to
+ * the Novell bug-tracker https://bugzilla.novell.com/show_bug.cgi?id=241950
+ */
+static int usb_host_scan_sys(void *opaque, USBScanFunc *func)
+{
+    DIR *dir = 0;
+    char line[1024];
+    int bus_num, addr, speed, class_id, product_id, vendor_id;
+    int ret = 0;
+    char product_name[512];
+    struct dirent *de;
+
+    dir = opendir(USBSYSBUS_PATH "/devices");
+    if (!dir) {
+        perror("husb: cannot open devices directory");
+        goto the_end;
+    }
+
+    while ((de = readdir(dir))) {
+        if (de->d_name[0] != '.' && !strchr(de->d_name, ':')) {
+            char *tmpstr = de->d_name;
+            if (!strncmp(de->d_name, "usb", 3))
+                tmpstr += 3;
+            bus_num = atoi(tmpstr);
+
+            if (!usb_host_read_file(line, sizeof(line), USBSYSBUS_PATH "/devices/%s/devnum", de->d_name))
+                goto the_end;
+            if (sscanf(line, "%d", &addr) != 1)
+                goto the_end;
+
+            if (!usb_host_read_file(line, sizeof(line), USBSYSBUS_PATH "/devices/%s/bDeviceClass", de->d_name))
+                goto the_end;
+            if (sscanf(line, "%x", &class_id) != 1)
+                goto the_end;
+
+            if (!usb_host_read_file(line, sizeof(line), USBSYSBUS_PATH "/devices/%s/idVendor", de->d_name))
+                goto the_end;
+            if (sscanf(line, "%x", &vendor_id) != 1)
+                goto the_end;
+
+            if (!usb_host_read_file(line, sizeof(line), USBSYSBUS_PATH "/devices/%s/idProduct", de->d_name))
+                goto the_end;
+            if (sscanf(line, "%x", &product_id) != 1)
+                goto the_end;
+
+            if (!usb_host_read_file(line, sizeof(line), USBSYSBUS_PATH "/devices/%s/product", de->d_name)) {
+                *product_name = 0;
+            } else {
+                if (strlen(line) > 0)
+                    line[strlen(line) - 1] = '\0';
+                pstrcpy(product_name, sizeof(product_name), line);
+            }
+
+            if (!usb_host_read_file(line, sizeof(line), USBSYSBUS_PATH "/devices/%s/speed", de->d_name))
+                goto the_end;
+            if (!strcmp(line, "480\n"))
+                speed = USB_SPEED_HIGH;
+            else if (!strcmp(line, "1.5\n"))
+                speed = USB_SPEED_LOW;
+            else
+                speed = USB_SPEED_FULL;
+
+            ret = func(opaque, bus_num, addr, class_id, vendor_id,
+                       product_id, product_name, speed);
+            if (ret)
+                goto the_end;
+        }
+    }
+ the_end:
+    if (dir)
+        closedir(dir);
+    return ret;
+}
+
+/*
+ * Determine how to access the host's USB devices and call the
+ * specific support function.
+ */
+static int usb_host_scan(void *opaque, USBScanFunc *func)
+{
+    FILE *f = 0;
+    DIR *dir = 0;
+    int ret = 0;
+    const char *fs_type[] = {"unknown", "proc", "dev", "sys"};
+    char devpath[PATH_MAX];
+
+    /* only check the host once */
+    if (!usb_fs_type) {
+        f = fopen(USBPROCBUS_PATH "/devices", "r");
+        if (f) {
+            /* devices found in /proc/bus/usb/ */
+            strcpy(devpath, USBPROCBUS_PATH);
+            usb_fs_type = USB_FS_PROC;
+            fclose(f);
+            dprintf(USBDBG_DEVOPENED, USBPROCBUS_PATH);
+            goto found_devices;
+        }
+        /* try additional methods if an access method hasn't been found yet */
+        f = fopen(USBDEVBUS_PATH "/devices", "r");
+        if (f) {
+            /* devices found in /dev/bus/usb/ */
+            strcpy(devpath, USBDEVBUS_PATH);
+            usb_fs_type = USB_FS_DEV;
+            fclose(f);
+            dprintf(USBDBG_DEVOPENED, USBDEVBUS_PATH);
+            goto found_devices;
+        }
+        dir = opendir(USBSYSBUS_PATH "/devices");
+        if (dir) {
+            /* devices found in /dev/bus/usb/ (yes - not a mistake!) */
+            strcpy(devpath, USBDEVBUS_PATH);
+            usb_fs_type = USB_FS_SYS;
+            closedir(dir);
+            dprintf(USBDBG_DEVOPENED, USBSYSBUS_PATH);
+            goto found_devices;
+        }
+    found_devices:
+        if (!usb_fs_type) {
+            term_printf("husb: unable to access USB devices\n");
+            return -ENOENT;
+        }
+
+        /* the module setting (used later for opening devices) */
+        usb_host_device_path = qemu_mallocz(strlen(devpath)+1);
+        if (usb_host_device_path) {
+            strcpy(usb_host_device_path, devpath);
+            term_printf("husb: using %s file-system with %s\n", fs_type[usb_fs_type], usb_host_device_path);
+        } else {
+            /* out of memory? */
+            perror("husb: unable to allocate memory for device path");
+            return -ENOMEM;
+        }
+    }
+
+    switch (usb_fs_type) {
+    case USB_FS_PROC:
+    case USB_FS_DEV:
+        ret = usb_host_scan_dev(opaque, func);
+        break;
+    case USB_FS_SYS:
+        ret = usb_host_scan_sys(opaque, func);
+        break;
+    default:
+        ret = -EINVAL;
+        break;
+    }
+    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);
+}
+
+/*
+ * Autoconnect filter
+ * Format:
+ *    auto:bus:dev[:vid:pid]
+ *    auto:bus.dev[:vid:pid]
+ *
+ *    bus  - bus number    (dec, * means any)
+ *    dev  - device number (dec, * means any)
+ *    vid  - vendor id     (hex, * means any)
+ *    pid  - product id    (hex, * means any)
+ *
+ *    See 'lsusb' output.
+ */
+static int parse_filter(const char *spec, struct USBAutoFilter *f)
+{
+    enum { BUS, DEV, VID, PID, DONE };
+    const char *p = spec;
+    int i;
+
+    f->bus_num    = -1;
+    f->addr       = -1;
+    f->vendor_id  = -1;
+    f->product_id = -1;
+
+    for (i = BUS; i < DONE; i++) {
+    	p = strpbrk(p, ":.");
+    	if (!p) break;
+        p++;
+ 
+    	if (*p == '*')
+            continue;
+
+        switch(i) {
+        case BUS: f->bus_num = strtol(p, NULL, 10);    break;
+        case DEV: f->addr    = strtol(p, NULL, 10);    break;
+        case VID: f->vendor_id  = strtol(p, NULL, 16); break;
+        case PID: f->product_id = strtol(p, NULL, 16); break;
+        }
+    }
+
+    if (i < DEV) {
+        fprintf(stderr, "husb: invalid auto filter spec %s\n", spec);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int match_filter(const struct USBAutoFilter *f1, 
+                        const struct USBAutoFilter *f2)
+{
+    return f1->bus_num    == f2->bus_num &&
+           f1->addr       == f2->addr &&
+           f1->vendor_id  == f2->vendor_id &&
+           f1->product_id == f2->product_id;
+}
+
+static int usb_host_auto_add(const char *spec)
+{
+    struct USBAutoFilter filter, *f;
+
+    if (parse_filter(spec, &filter) < 0)
+        return -1;
+
+    f = qemu_mallocz(sizeof(*f));
+    if (!f) {
+        fprintf(stderr, "husb: failed to allocate auto filter\n");
+        return -1;
+    }
+
+    *f = filter; 
+
+    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) {
+            fprintf(stderr, "husb: failed to allocate auto scan timer\n");
+            qemu_free(f);
+            return -1;
+        }
+
+        /* Check for new devices every two seconds */
+        qemu_mod_timer(usb_auto_timer, qemu_get_clock(rt_clock) + 2000);
+    }
+
+    dprintf("husb: added auto filter: bus_num %d addr %d vid %d pid %d\n",
+	f->bus_num, f->addr, f->vendor_id, f->product_id);
+
+    f->next = usb_auto_filter;
+    usb_auto_filter = f;
+
+    return 0;
+}
+
+static int usb_host_auto_del(const char *spec)
+{
+    struct USBAutoFilter *pf = usb_auto_filter;
+    struct USBAutoFilter **prev = &usb_auto_filter;
+    struct USBAutoFilter filter;
+
+    if (parse_filter(spec, &filter) < 0)
+        return -1;
+
+    while (pf) {
+        if (match_filter(pf, &filter)) {
+            dprintf("husb: removed auto filter: bus_num %d addr %d vid %d pid %d\n",
+	             pf->bus_num, pf->addr, pf->vendor_id, pf->product_id);
+
+            *prev = pf->next;
+
+	    if (!usb_auto_filter) {
+                /* No more filters. Stop scanning. */
+                qemu_del_timer(usb_auto_timer);
+                qemu_free_timer(usb_auto_timer);
+            }
+
+            return 0;
+        }
+
+        prev = &pf->next;
+        pf   = pf->next;
+    }
+
+    return -1;
+}
+
+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;
+}
+
+static void dec2str(int val, char *str, size_t size)
+{
+    if (val == -1)
+        snprintf(str, size, "*");
+    else
+        snprintf(str, size, "%d", val); 
+}
+
+static void hex2str(int val, char *str, size_t size)
+{
+    if (val == -1)
+        snprintf(str, size, "*");
+    else
+        snprintf(str, size, "%x", val);
+}
+
+void usb_host_info(void)
+{
+    struct USBAutoFilter *f;
+
+    usb_host_scan(NULL, usb_host_info_device);
+
+    if (usb_auto_filter)
+        term_printf("  Auto filters:\n");
+    for (f = usb_auto_filter; f; f = f->next) {
+        char bus[10], addr[10], vid[10], pid[10];
+        dec2str(f->bus_num, bus, sizeof(bus));
+        dec2str(f->addr, addr, sizeof(addr));
+        hex2str(f->vendor_id, vid, sizeof(vid));
+        hex2str(f->product_id, pid, sizeof(pid));
+    	term_printf("    Device %s.%s ID %s:%s\n", bus, addr, vid, pid);
+    }
+}