iowarrior.c

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/*
 *  Native support for the I/O-Warrior USB devices
 *
 *  Copyright (c) 2003-2005  Code Mercenaries GmbH
 *  written by Christian Lucht <[email protected]>
 *
 *  based on

 *  usb-skeleton.c by Greg Kroah-Hartman  <[email protected]>
 *  brlvger.c by Stephane Dalton  <[email protected]>
 *           and St�hane Doyon   <[email protected]>
 *
 *  Released under the GPLv2.
 */

#include <linux/module.h>
#include <linux/usb.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/usb/iowarrior.h>

/* Version Information */
#define DRIVER_VERSION "v0.4.0"
#define DRIVER_AUTHOR "Christian Lucht <[email protected]>"
#define DRIVER_DESC "USB IO-Warrior driver (Linux 2.6.x)"

#define USB_VENDOR_ID_CODEMERCS     1984
/* low speed iowarrior */
#define USB_DEVICE_ID_CODEMERCS_IOW40   0x1500
#define USB_DEVICE_ID_CODEMERCS_IOW24   0x1501
#define USB_DEVICE_ID_CODEMERCS_IOWPV1  0x1511
#define USB_DEVICE_ID_CODEMERCS_IOWPV2  0x1512
/* full speed iowarrior */
#define USB_DEVICE_ID_CODEMERCS_IOW56   0x1503

/* Get a minor range for your devices from the usb maintainer */
#ifdef CONFIG_USB_DYNAMIC_MINORS
#define IOWARRIOR_MINOR_BASE    0
#else
#define IOWARRIOR_MINOR_BASE    208 // SKELETON_MINOR_BASE 192 + 16, not official yet
#endif

/* interrupt input queue size */
#define MAX_INTERRUPT_BUFFER 16
/*
   maximum number of urbs that are submitted for writes at the same time,
   this applies to the IOWarrior56 only!
   IOWarrior24 and IOWarrior40 use synchronous usb_control_msg calls.
*/
#define MAX_WRITES_IN_FLIGHT 4

/* Use our own dbg macro */
#undef dbg
#define dbg( format, arg... ) do { if( debug ) printk( KERN_DEBUG __FILE__ ": " format "\n" , ## arg ); } while ( 0 )

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/* Module parameters */
static DEFINE_MUTEX(iowarrior_mutex);
static bool debug = 0;
module_param(debug, bool, 0644);
MODULE_PARM_DESC(debug, "debug=1 enables debugging messages");

static struct usb_driver iowarrior_driver;
static DEFINE_MUTEX(iowarrior_open_disc_lock);

/*--------------*/
/*     data     */
/*--------------*/

/* Structure to hold all of our device specific stuff */
struct iowarrior {
    struct mutex mutex;         /* locks this structure */
    struct usb_device *udev;        /* save off the usb device pointer */
    struct usb_interface *interface;    /* the interface for this device */
    unsigned char minor;            /* the starting minor number for this device */
    struct usb_endpoint_descriptor *int_out_endpoint;   /* endpoint for reading (needed for IOW56 only) */
    struct usb_endpoint_descriptor *int_in_endpoint;    /* endpoint for reading */
    struct urb *int_in_urb;     /* the urb for reading data */
    unsigned char *int_in_buffer;   /* buffer for data to be read */
    unsigned char serial_number;    /* to detect lost packages */
    unsigned char *read_queue;  /* size is MAX_INTERRUPT_BUFFER * packet size */
    wait_queue_head_t read_wait;
    wait_queue_head_t write_wait;   /* wait-queue for writing to the device */
    atomic_t write_busy;        /* number of write-urbs submitted */
    atomic_t read_idx;
    atomic_t intr_idx;
    spinlock_t intr_idx_lock;   /* protects intr_idx */
    atomic_t overflow_flag;     /* signals an index 'rollover' */
    int present;            /* this is 1 as long as the device is connected */
    int opened;         /* this is 1 if the device is currently open */
    char chip_serial[9];        /* the serial number string of the chip connected */
    int report_size;        /* number of bytes in a report */
    u16 product_id;
};

/*--------------*/
/*    globals   */
/*--------------*/

/*
 *  USB spec identifies 5 second timeouts.
 */
#define GET_TIMEOUT 5
#define USB_REQ_GET_REPORT  0x01
//#if 0
static int usb_get_report(struct usb_device *dev,
              struct usb_host_interface *inter, unsigned char type,
              unsigned char id, void *buf, int size)
{
    return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                   USB_REQ_GET_REPORT,
                   USB_DIR_IN | USB_TYPE_CLASS |
                   USB_RECIP_INTERFACE, (type << 8) + id,
                   inter->desc.bInterfaceNumber, buf, size,
                   GET_TIMEOUT*HZ);
}
//#endif

#define USB_REQ_SET_REPORT 0x09

static int usb_set_report(struct usb_interface *intf, unsigned char type,
              unsigned char id, void *buf, int size)
{
    return usb_control_msg(interface_to_usbdev(intf),
                   usb_sndctrlpipe(interface_to_usbdev(intf), 0),
                   USB_REQ_SET_REPORT,
                   USB_TYPE_CLASS | USB_RECIP_INTERFACE,
                   (type << 8) + id,
                   intf->cur_altsetting->desc.bInterfaceNumber, buf,
                   size, HZ);
}

/*---------------------*/
/* driver registration */
/*---------------------*/
/* table of devices that work with this driver */
static const struct usb_device_id iowarrior_ids[] = {
    {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW40)},
    {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW24)},
    {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV1)},
    {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOWPV2)},
    {USB_DEVICE(USB_VENDOR_ID_CODEMERCS, USB_DEVICE_ID_CODEMERCS_IOW56)},
    {}          /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, iowarrior_ids);

/*
 * USB callback handler for reading data
 */
static void iowarrior_callback(struct urb *urb)
{
    struct iowarrior *dev = urb->context;
    int intr_idx;
    int read_idx;
    int aux_idx;
    int offset;
    int status = urb->status;
    int retval;

    switch (status) {
    case 0:
        /* success */
        break;
    case -ECONNRESET:
    case -ENOENT:
    case -ESHUTDOWN:
        return;
    default:
        goto exit;
    }

    spin_lock(&dev->intr_idx_lock);
    intr_idx = atomic_read(&dev->intr_idx);
    /* aux_idx become previous intr_idx */
    aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
    read_idx = atomic_read(&dev->read_idx);

    /* queue is not empty and it's interface 0 */
    if ((intr_idx != read_idx)
        && (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0)) {
        /* + 1 for serial number */
        offset = aux_idx * (dev->report_size + 1);
        if (!memcmp
            (dev->read_queue + offset, urb->transfer_buffer,
             dev->report_size)) {
            /* equal values on interface 0 will be ignored */
            spin_unlock(&dev->intr_idx_lock);
            goto exit;
        }
    }

    /* aux_idx become next intr_idx */
    aux_idx = (intr_idx == (MAX_INTERRUPT_BUFFER - 1)) ? 0 : (intr_idx + 1);
    if (read_idx == aux_idx) {
        /* queue full, dropping oldest input */
        read_idx = (++read_idx == MAX_INTERRUPT_BUFFER) ? 0 : read_idx;
        atomic_set(&dev->read_idx, read_idx);
        atomic_set(&dev->overflow_flag, 1);
    }

    /* +1 for serial number */
    offset = intr_idx * (dev->report_size + 1);
    memcpy(dev->read_queue + offset, urb->transfer_buffer,
           dev->report_size);
    *(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;

    atomic_set(&dev->intr_idx, aux_idx);
    spin_unlock(&dev->intr_idx_lock);
    /* tell the blocking read about the new data */
    wake_up_interruptible(&dev->read_wait);

exit:
    retval = usb_submit_urb(urb, GFP_ATOMIC);
    if (retval)
        dev_err(&dev->interface->dev, "%s - usb_submit_urb failed with result %d\n",
            __func__, retval);

}

/*
 * USB Callback handler for write-ops
 */
static void iowarrior_write_callback(struct urb *urb)
{
    struct iowarrior *dev;
    int status = urb->status;

    dev = urb->context;
    /* sync/async unlink faults aren't errors */
    if (status &&
        !(status == -ENOENT ||
          status == -ECONNRESET || status == -ESHUTDOWN)) {
        dbg("%s - nonzero write bulk status received: %d",
            __func__, status);
    }
    /* free up our allocated buffer */
    usb_free_coherent(urb->dev, urb->transfer_buffer_length,
              urb->transfer_buffer, urb->transfer_dma);
    /* tell a waiting writer the interrupt-out-pipe is available again */
    atomic_dec(&dev->write_busy);
    wake_up_interruptible(&dev->write_wait);
}

static inline void iowarrior_delete(struct iowarrior *dev)
{
    dbg("%s - minor %d", __func__, dev->minor);
    kfree(dev->int_in_buffer);
    usb_free_urb(dev->int_in_urb);
    kfree(dev->read_queue);
    kfree(dev);
}

/*---------------------*/
/* fops implementation */
/*---------------------*/

static int read_index(struct iowarrior *dev)
{
    int intr_idx, read_idx;

    read_idx = atomic_read(&dev->read_idx);
    intr_idx = atomic_read(&dev->intr_idx);

    return (read_idx == intr_idx ? -1 : read_idx);
}

static ssize_t iowarrior_read(struct file *file, char __user *buffer,
                  size_t count, loff_t *ppos)
{
    struct iowarrior *dev;
    int read_idx;
    int offset;

    dev = file->private_data;

    /* verify that the device wasn't unplugged */
    if (dev == NULL || !dev->present)
        return -ENODEV;

    dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);

    /* read count must be packet size (+ time stamp) */
    if ((count != dev->report_size)
        && (count != (dev->report_size + 1)))
        return -EINVAL;

    /* repeat until no buffer overrun in callback handler occur */
    do {
        atomic_set(&dev->overflow_flag, 0);
        if ((read_idx = read_index(dev)) == -1) {
            /* queue emty */
            if (file->f_flags & O_NONBLOCK)
                return -EAGAIN;
            else {
                //next line will return when there is either new data, or the device is unplugged
                int r = wait_event_interruptible(dev->read_wait,
                                 (!dev->present
                                  || (read_idx =
                                      read_index
                                      (dev)) !=
                                  -1));
                if (r) {
                    //we were interrupted by a signal
                    return -ERESTART;
                }
                if (!dev->present) {
                    //The device was unplugged
                    return -ENODEV;
                }
                if (read_idx == -1) {
                    // Can this happen ???
                    return 0;
                }
            }
        }

        offset = read_idx * (dev->report_size + 1);
        if (copy_to_user(buffer, dev->read_queue + offset, count)) {
            return -EFAULT;
        }
    } while (atomic_read(&dev->overflow_flag));

    read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx;
    atomic_set(&dev->read_idx, read_idx);
    return count;
}

/*
 * iowarrior_write
 */
static ssize_t iowarrior_write(struct file *file,
                   const char __user *user_buffer,
                   size_t count, loff_t *ppos)
{
    struct iowarrior *dev;
    int retval = 0;
    char *buf = NULL;   /* for IOW24 and IOW56 we need a buffer */
    struct urb *int_out_urb = NULL;

    dev = file->private_data;

    mutex_lock(&dev->mutex);
    /* verify that the device wasn't unplugged */
    if (!dev->present) {
        retval = -ENODEV;
        goto exit;
    }
    dbg("%s - minor %d, count = %zd", __func__, dev->minor, count);
    /* if count is 0 we're already done */
    if (count == 0) {
        retval = 0;
        goto exit;
    }
    /* We only accept full reports */
    if (count != dev->report_size) {
        retval = -EINVAL;
        goto exit;
    }
    switch (dev->product_id) {
    case USB_DEVICE_ID_CODEMERCS_IOW24:
    case USB_DEVICE_ID_CODEMERCS_IOWPV1:
    case USB_DEVICE_ID_CODEMERCS_IOWPV2:
    case USB_DEVICE_ID_CODEMERCS_IOW40:
        /* IOW24 and IOW40 use a synchronous call */
        buf = kmalloc(count, GFP_KERNEL);
        if (!buf) {
            retval = -ENOMEM;
            goto exit;
        }
        if (copy_from_user(buf, user_buffer, count)) {
            retval = -EFAULT;
            kfree(buf);
            goto exit;
        }
        retval = usb_set_report(dev->interface, 2, 0, buf, count);
        kfree(buf);
        goto exit;
        break;
    case USB_DEVICE_ID_CODEMERCS_IOW56:
        /* The IOW56 uses asynchronous IO and more urbs */
        if (atomic_read(&dev->write_busy) == MAX_WRITES_IN_FLIGHT) {
            /* Wait until we are below the limit for submitted urbs */
            if (file->f_flags & O_NONBLOCK) {
                retval = -EAGAIN;
                goto exit;
            } else {
                retval = wait_event_interruptible(dev->write_wait,
                                  (!dev->present || (atomic_read (&dev-> write_busy) < MAX_WRITES_IN_FLIGHT)));
                if (retval) {
                    /* we were interrupted by a signal */
                    retval = -ERESTART;
                    goto exit;
                }
                if (!dev->present) {
                    /* The device was unplugged */
                    retval = -ENODEV;
                    goto exit;
                }
                if (!dev->opened) {
                    /* We were closed while waiting for an URB */
                    retval = -ENODEV;
                    goto exit;
                }
            }
        }
        atomic_inc(&dev->write_busy);
        int_out_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!int_out_urb) {
            retval = -ENOMEM;
            dbg("%s Unable to allocate urb ", __func__);
            goto error_no_urb;
        }
        buf = usb_alloc_coherent(dev->udev, dev->report_size,
                     GFP_KERNEL, &int_out_urb->transfer_dma);
        if (!buf) {
            retval = -ENOMEM;
            dbg("%s Unable to allocate buffer ", __func__);
            goto error_no_buffer;
        }
        usb_fill_int_urb(int_out_urb, dev->udev,
                 usb_sndintpipe(dev->udev,
                        dev->int_out_endpoint->bEndpointAddress),
                 buf, dev->report_size,
                 iowarrior_write_callback, dev,
                 dev->int_out_endpoint->bInterval);
        int_out_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
        if (copy_from_user(buf, user_buffer, count)) {
            retval = -EFAULT;
            goto error;
        }
        retval = usb_submit_urb(int_out_urb, GFP_KERNEL);
        if (retval) {
            dbg("%s submit error %d for urb nr.%d", __func__,
                retval, atomic_read(&dev->write_busy));
            goto error;
        }
        /* submit was ok */
        retval = count;
        usb_free_urb(int_out_urb);
        goto exit;
        break;
    default:
        /* what do we have here ? An unsupported Product-ID ? */
        dev_err(&dev->interface->dev, "%s - not supported for product=0x%x\n",
            __func__, dev->product_id);
        retval = -EFAULT;
        goto exit;
        break;
    }
error:
    usb_free_coherent(dev->udev, dev->report_size, buf,
              int_out_urb->transfer_dma);
error_no_buffer:
    usb_free_urb(int_out_urb);
error_no_urb:
    atomic_dec(&dev->write_busy);
    wake_up_interruptible(&dev->write_wait);
exit:
    mutex_unlock(&dev->mutex);
    return retval;
}

static long iowarrior_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
    struct iowarrior *dev = NULL;
    __u8 *buffer;
    __u8 __user *user_buffer;
    int retval;
    int io_res;     /* checks for bytes read/written and copy_to/from_user results */

    dev = file->private_data;
    if (dev == NULL) {
        return -ENODEV;
    }

    buffer = kzalloc(dev->report_size, GFP_KERNEL);
    if (!buffer)
        return -ENOMEM;

    /* lock this object */
    mutex_lock(&iowarrior_mutex);
    mutex_lock(&dev->mutex);

    /* verify that the device wasn't unplugged */
    if (!dev->present) {
        retval = -ENODEV;
        goto error_out;
    }

    dbg("%s - minor %d, cmd 0x%.4x, arg %ld", __func__, dev->minor, cmd,
        arg);

    retval = 0;
    io_res = 0;
    switch (cmd) {
    case IOW_WRITE:
        if (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW24 ||
            dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV1 ||
            dev->product_id == USB_DEVICE_ID_CODEMERCS_IOWPV2 ||
            dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW40) {
            user_buffer = (__u8 __user *)arg;
            io_res = copy_from_user(buffer, user_buffer,
                        dev->report_size);
            if (io_res) {
                retval = -EFAULT;
            } else {
                io_res = usb_set_report(dev->interface, 2, 0,
                            buffer,
                            dev->report_size);
                if (io_res < 0)
                    retval = io_res;
            }
        } else {
            retval = -EINVAL;
            dev_err(&dev->interface->dev,
                "ioctl 'IOW_WRITE' is not supported for product=0x%x.\n",
                dev->product_id);
        }
        break;
    case IOW_READ:
        user_buffer = (__u8 __user *)arg;
        io_res = usb_get_report(dev->udev,
                    dev->interface->cur_altsetting, 1, 0,
                    buffer, dev->report_size);
        if (io_res < 0)
            retval = io_res;
        else {
            io_res = copy_to_user(user_buffer, buffer, dev->report_size);
            if (io_res)
                retval = -EFAULT;
        }
        break;
    case IOW_GETINFO:
        {
            /* Report available information for the device */
            struct iowarrior_info info;
            /* needed for power consumption */
            struct usb_config_descriptor *cfg_descriptor = &dev->udev->actconfig->desc;

            memset(&info, 0, sizeof(info));
            /* directly from the descriptor */
            info.vendor = le16_to_cpu(dev->udev->descriptor.idVendor);
            info.product = dev->product_id;
            info.revision = le16_to_cpu(dev->udev->descriptor.bcdDevice);

            /* 0==UNKNOWN, 1==LOW(usb1.1) ,2=FULL(usb1.1), 3=HIGH(usb2.0) */
            info.speed = le16_to_cpu(dev->udev->speed);
            info.if_num = dev->interface->cur_altsetting->desc.bInterfaceNumber;
            info.report_size = dev->report_size;

            /* serial number string has been read earlier 8 chars or empty string */
            memcpy(info.serial, dev->chip_serial,
                   sizeof(dev->chip_serial));
            if (cfg_descriptor == NULL) {
                info.power = -1;    /* no information available */
            } else {
                /* the MaxPower is stored in units of 2mA to make it fit into a byte-value */
                info.power = cfg_descriptor->bMaxPower * 2;
            }
            io_res = copy_to_user((struct iowarrior_info __user *)arg, &info,
                     sizeof(struct iowarrior_info));
            if (io_res)
                retval = -EFAULT;
            break;
        }
    default:
        /* return that we did not understand this ioctl call */
        retval = -ENOTTY;
        break;
    }
error_out:
    /* unlock the device */
    mutex_unlock(&dev->mutex);
    mutex_unlock(&iowarrior_mutex);
    kfree(buffer);
    return retval;
}

static int iowarrior_open(struct inode *inode, struct file *file)
{
    struct iowarrior *dev = NULL;
    struct usb_interface *interface;
    int subminor;
    int retval = 0;

    dbg("%s", __func__);

    mutex_lock(&iowarrior_mutex);
    subminor = iminor(inode);

    interface = usb_find_interface(&iowarrior_driver, subminor);
    if (!interface) {
        mutex_unlock(&iowarrior_mutex);
        printk(KERN_ERR "%s - error, can't find device for minor %d\n",
               __func__, subminor);
        return -ENODEV;
    }

    mutex_lock(&iowarrior_open_disc_lock);
    dev = usb_get_intfdata(interface);
    if (!dev) {
        mutex_unlock(&iowarrior_open_disc_lock);
        mutex_unlock(&iowarrior_mutex);
        return -ENODEV;
    }

    mutex_lock(&dev->mutex);
    mutex_unlock(&iowarrior_open_disc_lock);

    /* Only one process can open each device, no sharing. */
    if (dev->opened) {
        retval = -EBUSY;
        goto out;
    }

    /* setup interrupt handler for receiving values */
    if ((retval = usb_submit_urb(dev->int_in_urb, GFP_KERNEL)) < 0) {
        dev_err(&interface->dev, "Error %d while submitting URB\n", retval);
        retval = -EFAULT;
        goto out;
    }
    /* increment our usage count for the driver */
    ++dev->opened;
    /* save our object in the file's private structure */
    file->private_data = dev;
    retval = 0;

out:
    mutex_unlock(&dev->mutex);
    mutex_unlock(&iowarrior_mutex);
    return retval;
}

static int iowarrior_release(struct inode *inode, struct file *file)
{
    struct iowarrior *dev;
    int retval = 0;

    dev = file->private_data;
    if (dev == NULL) {
        return -ENODEV;
    }

    dbg("%s - minor %d", __func__, dev->minor);

    /* lock our device */
    mutex_lock(&dev->mutex);

    if (dev->opened <= 0) {
        retval = -ENODEV;   /* close called more than once */
        mutex_unlock(&dev->mutex);
    } else {
        dev->opened = 0;    /* we're closeing now */
        retval = 0;
        if (dev->present) {
            /*
               The device is still connected so we only shutdown
               pending read-/write-ops.
             */
            usb_kill_urb(dev->int_in_urb);
            wake_up_interruptible(&dev->read_wait);
            wake_up_interruptible(&dev->write_wait);
            mutex_unlock(&dev->mutex);
        } else {
            /* The device was unplugged, cleanup resources */
            mutex_unlock(&dev->mutex);
            iowarrior_delete(dev);
        }
    }
    return retval;
}

static unsigned iowarrior_poll(struct file *file, poll_table * wait)
{
    struct iowarrior *dev = file->private_data;
    unsigned int mask = 0;

    if (!dev->present)
        return POLLERR | POLLHUP;

    poll_wait(file, &dev->read_wait, wait);
    poll_wait(file, &dev->write_wait, wait);

    if (!dev->present)
        return POLLERR | POLLHUP;

    if (read_index(dev) != -1)
        mask |= POLLIN | POLLRDNORM;

    if (atomic_read(&dev->write_busy) < MAX_WRITES_IN_FLIGHT)
        mask |= POLLOUT | POLLWRNORM;
    return mask;
}

/*
 * File operations needed when we register this driver.
 * This assumes that this driver NEEDS file operations,
 * of course, which means that the driver is expected
 * to have a node in the /dev directory. If the USB
 * device were for a network interface then the driver
 * would use "struct net_driver" instead, and a serial
 * device would use "struct tty_driver".
 */
static const struct file_operations iowarrior_fops = {
    .owner = THIS_MODULE,
    .write = iowarrior_write,
    .read = iowarrior_read,
    .unlocked_ioctl = iowarrior_ioctl,
    .open = iowarrior_open,
    .release = iowarrior_release,
    .poll = iowarrior_poll,
    .llseek = noop_llseek,
};

static char *iowarrior_devnode(struct device *dev, umode_t *mode)
{
    return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
}

/*
 * usb class driver info in order to get a minor number from the usb core,
 * and to have the device registered with devfs and the driver core
 */
static struct usb_class_driver iowarrior_class = {
    .name = "iowarrior%d",
    .devnode = iowarrior_devnode,
    .fops = &iowarrior_fops,
    .minor_base = IOWARRIOR_MINOR_BASE,
};

/*---------------------------------*/
/*  probe and disconnect functions */
/*---------------------------------*/
static int iowarrior_probe(struct usb_interface *interface,
               const struct usb_device_id *id)
{
    struct usb_device *udev = interface_to_usbdev(interface);
    struct iowarrior *dev = NULL;
    struct usb_host_interface *iface_desc;
    struct usb_endpoint_descriptor *endpoint;
    int i;
    int retval = -ENOMEM;

    /* allocate memory for our device state and initialize it */
    dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);
    if (dev == NULL) {
        dev_err(&interface->dev, "Out of memory\n");
        return retval;
    }

    mutex_init(&dev->mutex);

    atomic_set(&dev->intr_idx, 0);
    atomic_set(&dev->read_idx, 0);
    spin_lock_init(&dev->intr_idx_lock);
    atomic_set(&dev->overflow_flag, 0);
    init_waitqueue_head(&dev->read_wait);
    atomic_set(&dev->write_busy, 0);
    init_waitqueue_head(&dev->write_wait);

    dev->udev = udev;
    dev->interface = interface;

    iface_desc = interface->cur_altsetting;
    dev->product_id = le16_to_cpu(udev->descriptor.idProduct);

    /* set up the endpoint information */
    for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
        endpoint = &iface_desc->endpoint[i].desc;

        if (usb_endpoint_is_int_in(endpoint))
            dev->int_in_endpoint = endpoint;
        if (usb_endpoint_is_int_out(endpoint))
            /* this one will match for the IOWarrior56 only */
            dev->int_out_endpoint = endpoint;
    }
    /* we have to check the report_size often, so remember it in the endianess suitable for our machine */
    dev->report_size = usb_endpoint_maxp(dev->int_in_endpoint);
    if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
        (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56))
        /* IOWarrior56 has wMaxPacketSize different from report size */
        dev->report_size = 7;

    /* create the urb and buffer for reading */
    dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
    if (!dev->int_in_urb) {
        dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
        goto error;
    }
    dev->int_in_buffer = kmalloc(dev->report_size, GFP_KERNEL);
    if (!dev->int_in_buffer) {
        dev_err(&interface->dev, "Couldn't allocate int_in_buffer\n");
        goto error;
    }
    usb_fill_int_urb(dev->int_in_urb, dev->udev,
             usb_rcvintpipe(dev->udev,
                    dev->int_in_endpoint->bEndpointAddress),
             dev->int_in_buffer, dev->report_size,
             iowarrior_callback, dev,
             dev->int_in_endpoint->bInterval);
    /* create an internal buffer for interrupt data from the device */
    dev->read_queue =
        kmalloc(((dev->report_size + 1) * MAX_INTERRUPT_BUFFER),
            GFP_KERNEL);
    if (!dev->read_queue) {
        dev_err(&interface->dev, "Couldn't allocate read_queue\n");
        goto error;
    }
    /* Get the serial-number of the chip */
    memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));
    usb_string(udev, udev->descriptor.iSerialNumber, dev->chip_serial,
           sizeof(dev->chip_serial));
    if (strlen(dev->chip_serial) != 8)
        memset(dev->chip_serial, 0x00, sizeof(dev->chip_serial));

    /* Set the idle timeout to 0, if this is interface 0 */
    if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
        usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
                0x0A,
                USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0,
                0, NULL, 0, USB_CTRL_SET_TIMEOUT);
    }
    /* allow device read and ioctl */
    dev->present = 1;

    /* we can register the device now, as it is ready */
    usb_set_intfdata(interface, dev);

    retval = usb_register_dev(interface, &iowarrior_class);
    if (retval) {
        /* something prevented us from registering this driver */
        dev_err(&interface->dev, "Not able to get a minor for this device.\n");
        usb_set_intfdata(interface, NULL);
        goto error;
    }

    dev->minor = interface->minor;

    /* let the user know what node this device is now attached to */
    dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
         "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
         iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
    return retval;

error:
    iowarrior_delete(dev);
    return retval;
}

static void iowarrior_disconnect(struct usb_interface *interface)
{
    struct iowarrior *dev;
    int minor;

    dev = usb_get_intfdata(interface);
    mutex_lock(&iowarrior_open_disc_lock);
    usb_set_intfdata(interface, NULL);

    minor = dev->minor;

    /* give back our minor */
    usb_deregister_dev(interface, &iowarrior_class);

    mutex_lock(&dev->mutex);

    /* prevent device read, write and ioctl */
    dev->present = 0;

    mutex_unlock(&dev->mutex);
    mutex_unlock(&iowarrior_open_disc_lock);

    if (dev->opened) {
        /* There is a process that holds a filedescriptor to the device ,
           so we only shutdown read-/write-ops going on.
           Deleting the device is postponed until close() was called.
         */
        usb_kill_urb(dev->int_in_urb);
        wake_up_interruptible(&dev->read_wait);
        wake_up_interruptible(&dev->write_wait);
    } else {
        /* no process is using the device, cleanup now */
        iowarrior_delete(dev);
    }

    dev_info(&interface->dev, "I/O-Warror #%d now disconnected\n",
         minor - IOWARRIOR_MINOR_BASE);
}

/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver iowarrior_driver = {
    .name = "iowarrior",
    .probe = iowarrior_probe,
    .disconnect = iowarrior_disconnect,
    .id_table = iowarrior_ids,
};

module_usb_driver(iowarrior_driver);