/*
 * USB driver for Gigaset 307x directly or using M105 Data.
 *
 * Copyright (c) 2001 by Stefan Eilers
 *                   and Hansjoerg Lipp <hjlipp@web.de>.
 *
 * This driver was derived from the USB skeleton driver by
 * Greg Kroah-Hartman <greg@kroah.com>
 *
 * =====================================================================
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License as
 *      published by the Free Software Foundation; either version 2 of
 *      the License, or (at your option) any later version.
 * =====================================================================
 */

#include "gigaset.h"
#include <linux/usb.h>
#include <linux/module.h>
#include <linux/moduleparam.h>

/* Version Information */
#define DRIVER_AUTHOR "Hansjoerg Lipp <hjlipp@web.de>, Stefan Eilers"
#define DRIVER_DESC "USB Driver for Gigaset 307x using M105"

/* Module parameters */

static int startmode = SM_ISDN;
static int cidmode = 1;

module_param(startmode, int, S_IRUGO);
module_param(cidmode, int, S_IRUGO);
MODULE_PARM_DESC(startmode, "start in isdn4linux mode");
MODULE_PARM_DESC(cidmode, "Call-ID mode");

#define GIGASET_MINORS     1
#define GIGASET_MINOR      8
#define GIGASET_MODULENAME "usb_gigaset"
#define GIGASET_DEVNAME    "ttyGU"

/* length limit according to Siemens 3070usb-protokoll.doc ch. 2.1 */
#define IF_WRITEBUF 264

/* Values for the Gigaset M105 Data */
#define USB_M105_VENDOR_ID      0x0681
#define USB_M105_PRODUCT_ID     0x0009

/* table of devices that work with this driver */
static const struct usb_device_id gigaset_table[] = {
        { USB_DEVICE(USB_M105_VENDOR_ID, USB_M105_PRODUCT_ID) },
        { }                                     /* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, gigaset_table);

/*
 * Control requests (empty fields: 00)
 *
 *       RT|RQ|VALUE|INDEX|LEN  |DATA
 * In:
 *       C1 08             01
 *            Get flags (1 byte). Bits: 0=dtr,1=rts,3-7:?
 *       C1 0F             ll ll
 *            Get device information/status (llll: 0x200 and 0x40 seen).
 *            Real size: I only saw MIN(llll,0x64).
 *            Contents: seems to be always the same...
 *              offset 0x00: Length of this structure (0x64) (len: 1,2,3 bytes)
 *              offset 0x3c: String (16 bit chars): "MCCI USB Serial V2.0"
 *              rest:        ?
 * Out:
 *       41 11
 *            Initialize/reset device ?
 *       41 00 xx 00
 *            ? (xx=00 or 01; 01 on start, 00 on close)
 *       41 07 vv mm
 *            Set/clear flags vv=value, mm=mask (see RQ 08)
 *       41 12 xx
 *            Used before the following configuration requests are issued
 *            (with xx=0x0f). I've seen other values<0xf, though.
 *       41 01 xx xx
 *            Set baud rate. xxxx=ceil(0x384000/rate)=trunc(0x383fff/rate)+1.
 *       41 03 ps bb
 *            Set byte size and parity. p:  0x20=even,0x10=odd,0x00=no parity
 *                                     [    0x30: m, 0x40: s           ]
 *                                     [s:  0: 1 stop bit; 1: 1.5; 2: 2]
 *                                      bb: bits/byte (seen 7 and 8)
 *       41 13 -- -- -- -- 10 00 ww 00 00 00 xx 00 00 00 yy 00 00 00 zz 00 00 00
 *            ??
 *            Initialization: 01, 40, 00, 00
 *            Open device:    00  40, 00, 00
 *            yy and zz seem to be equal, either 0x00 or 0x0a
 *            (ww,xx) pairs seen: (00,00), (00,40), (01,40), (09,80), (19,80)
 *       41 19 -- -- -- -- 06 00 00 00 00 xx 11 13
 *            Used after every "configuration sequence" (RQ 12, RQs 01/03/13).
 *            xx is usually 0x00 but was 0x7e before starting data transfer
 *            in unimodem mode. So, this might be an array of characters that
 *            need special treatment ("commit all bufferd data"?), 11=^Q, 13=^S.
 *
 * Unimodem mode: use "modprobe ppp_async flag_time=0" as the device _needs_ two
 * flags per packet.
 */

/* functions called if a device of this driver is connected/disconnected */
static int gigaset_probe(struct usb_interface *interface,
                         const struct usb_device_id *id);
static void gigaset_disconnect(struct usb_interface *interface);

/* functions called before/after suspend */
static int gigaset_suspend(struct usb_interface *intf, pm_message_t message);
static int gigaset_resume(struct usb_interface *intf);
static int gigaset_pre_reset(struct usb_interface *intf);

static struct gigaset_driver *driver;

/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver gigaset_usb_driver = {
        .name =         GIGASET_MODULENAME,
        .probe =        gigaset_probe,
        .disconnect =   gigaset_disconnect,
        .id_table =     gigaset_table,
        .suspend =      gigaset_suspend,
        .resume =       gigaset_resume,
        .reset_resume = gigaset_resume,
        .pre_reset =    gigaset_pre_reset,
        .post_reset =   gigaset_resume,
        .disable_hub_initiated_lpm = 1,
};

struct usb_cardstate {
        struct usb_device       *udev;          /* usb device pointer */
        struct usb_interface    *interface;     /* interface for this device */
        int                     busy;           /* bulk output in progress */

        /* Output buffer */
        unsigned char           *bulk_out_buffer;
        int                     bulk_out_size;
        int                     bulk_out_epnum;
        struct urb              *bulk_out_urb;

        /* Input buffer */
        unsigned char           *rcvbuf;
        int                     rcvbuf_size;
        struct urb              *read_urb;

        char                    bchars[6];              /* for request 0x19 */
};

static inline unsigned tiocm_to_gigaset(unsigned state)
{
        return ((state & TIOCM_DTR) ? 1 : 0) | ((state & TIOCM_RTS) ? 2 : 0);
}

static int gigaset_set_modem_ctrl(struct cardstate *cs, unsigned old_state,
                                  unsigned new_state)
{
        struct usb_device *udev = cs->hw.usb->udev;
        unsigned mask, val;
        int r;

        mask = tiocm_to_gigaset(old_state ^ new_state);
        val = tiocm_to_gigaset(new_state);

        gig_dbg(DEBUG_USBREQ, "set flags 0x%02x with mask 0x%02x", val, mask);
        r = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 7, 0x41,
                            (val & 0xff) | ((mask & 0xff) << 8), 0,
                            NULL, 0, 2000 /* timeout? */);
        if (r < 0)
                return r;
        return 0;
}

/*
 * Set M105 configuration value
 * using undocumented device commands reverse engineered from USB traces
 * of the Siemens Windows driver
 */
static int set_value(struct cardstate *cs, u8 req, u16 val)
{
        struct usb_device *udev = cs->hw.usb->udev;
        int r, r2;

        gig_dbg(DEBUG_USBREQ, "request %02x (%04x)",
                (unsigned)req, (unsigned)val);
        r = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x12, 0x41,
                            0xf /*?*/, 0, NULL, 0, 2000 /*?*/);
        /* no idea what this does */
        if (r < 0) {
                dev_err(&udev->dev, "error %d on request 0x12\n", -r);
                return r;
        }

        r = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), req, 0x41,
                            val, 0, NULL, 0, 2000 /*?*/);
        if (r < 0)
                dev_err(&udev->dev, "error %d on request 0x%02x\n",
                        -r, (unsigned)req);

        r2 = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x19, 0x41,
                             0, 0, cs->hw.usb->bchars, 6, 2000 /*?*/);
        if (r2 < 0)
                dev_err(&udev->dev, "error %d on request 0x19\n", -r2);

        return r < 0 ? r : (r2 < 0 ? r2 : 0);
}

/*
 * set the baud rate on the internal serial adapter
 * using the undocumented parameter setting command
 */
static int gigaset_baud_rate(struct cardstate *cs, unsigned cflag)
{
        u16 val;
        u32 rate;

        cflag &= CBAUD;

        switch (cflag) {
        case    B300: rate =     300; break;
        case    B600: rate =     600; break;
        case   B1200: rate =    1200; break;
        case   B2400: rate =    2400; break;
        case   B4800: rate =    4800; break;
        case   B9600: rate =    9600; break;
        case  B19200: rate =   19200; break;
        case  B38400: rate =   38400; break;
        case  B57600: rate =   57600; break;
        case B115200: rate =  115200; break;
        default:
                rate =  9600;
                dev_err(cs->dev, "unsupported baudrate request 0x%x,"
                        " using default of B9600\n", cflag);
        }

        val = 0x383fff / rate + 1;

        return set_value(cs, 1, val);
}

/*
 * set the line format on the internal serial adapter
 * using the undocumented parameter setting command
 */
static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
{
        u16 val = 0;

        /* set the parity */
        if (cflag & PARENB)
                val |= (cflag & PARODD) ? 0x10 : 0x20;

        /* set the number of data bits */
        switch (cflag & CSIZE) {
        case CS5:
                val |= 5 << 8; break;
        case CS6:
                val |= 6 << 8; break;
        case CS7:
                val |= 7 << 8; break;
        case CS8:
                val |= 8 << 8; break;
        default:
                dev_err(cs->dev, "CSIZE was not CS5-CS8, using default of 8\n");
                val |= 8 << 8;
                break;
        }

        /* set the number of stop bits */
        if (cflag & CSTOPB) {
                if ((cflag & CSIZE) == CS5)
                        val |= 1; /* 1.5 stop bits */
                else
                        val |= 2; /* 2 stop bits */
        }

        return set_value(cs, 3, val);
}


/*============================================================================*/
static int gigaset_init_bchannel(struct bc_state *bcs)
{
        /* nothing to do for M10x */
        gigaset_bchannel_up(bcs);
        return 0;
}

static int gigaset_close_bchannel(struct bc_state *bcs)
{
        /* nothing to do for M10x */
        gigaset_bchannel_down(bcs);
        return 0;
}

static int write_modem(struct cardstate *cs);
static int send_cb(struct cardstate *cs);


/* Write tasklet handler: Continue sending current skb, or send command, or
 * start sending an skb from the send queue.
 */
static void gigaset_modem_fill(unsigned long data)
{
        struct cardstate *cs = (struct cardstate *) data;
        struct bc_state *bcs = &cs->bcs[0]; /* only one channel */

        gig_dbg(DEBUG_OUTPUT, "modem_fill");

        if (cs->hw.usb->busy) {
                gig_dbg(DEBUG_OUTPUT, "modem_fill: busy");
                return;
        }

again:
        if (!bcs->tx_skb) {     /* no skb is being sent */
                if (cs->cmdbuf) {       /* commands to send? */
                        gig_dbg(DEBUG_OUTPUT, "modem_fill: cb");
                        if (send_cb(cs) < 0) {
                                gig_dbg(DEBUG_OUTPUT,
                                        "modem_fill: send_cb failed");
                                goto again; /* no callback will be called! */
                        }
                        return;
                }

                /* skbs to send? */
                bcs->tx_skb = skb_dequeue(&bcs->squeue);
                if (!bcs->tx_skb)
                        return;

                gig_dbg(DEBUG_INTR, "Dequeued skb (Adr: %lx)!",
                        (unsigned long) bcs->tx_skb);
        }

        gig_dbg(DEBUG_OUTPUT, "modem_fill: tx_skb");
        if (write_modem(cs) < 0) {
                gig_dbg(DEBUG_OUTPUT, "modem_fill: write_modem failed");
                goto again;     /* no callback will be called! */
        }
}

/*
 * Interrupt Input URB completion routine
 */
static void gigaset_read_int_callback(struct urb *urb)
{
        struct cardstate *cs = urb->context;
        struct inbuf_t *inbuf = cs->inbuf;
        int status = urb->status;
        int r;
        unsigned numbytes;
        unsigned char *src;
        unsigned long flags;

        if (!status) {
                numbytes = urb->actual_length;

                if (numbytes) {
                        src = cs->hw.usb->rcvbuf;
                        if (unlikely(*src))
                                dev_warn(cs->dev,
                                         "%s: There was no leading 0, but 0x%02x!\n",
                                         __func__, (unsigned) *src);
                        ++src; /* skip leading 0x00 */
                        --numbytes;
                        if (gigaset_fill_inbuf(inbuf, src, numbytes)) {
                                gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
                                gigaset_schedule_event(inbuf->cs);
                        }
                } else
                        gig_dbg(DEBUG_INTR, "Received zero block length");
        } else {
                /* The urb might have been killed. */
                gig_dbg(DEBUG_ANY, "%s - nonzero status received: %d",
                        __func__, status);
                if (status == -ENOENT || status == -ESHUTDOWN)
                        /* killed or endpoint shutdown: don't resubmit */
                        return;
        }

        /* resubmit URB */
        spin_lock_irqsave(&cs->lock, flags);
        if (!cs->connected) {
                spin_unlock_irqrestore(&cs->lock, flags);
                pr_err("%s: disconnected\n", __func__);
                return;
        }
        r = usb_submit_urb(urb, GFP_ATOMIC);
        spin_unlock_irqrestore(&cs->lock, flags);
        if (r)
                dev_err(cs->dev, "error %d resubmitting URB\n", -r);
}


/* This callback routine is called when data was transmitted to the device. */
static void gigaset_write_bulk_callback(struct urb *urb)
{
        struct cardstate *cs = urb->context;
        int status = urb->status;
        unsigned long flags;

        switch (status) {
        case 0:                 /* normal completion */
                break;
        case -ENOENT:           /* killed */
                gig_dbg(DEBUG_ANY, "%s: killed", __func__);
                cs->hw.usb->busy = 0;
                return;
        default:
                dev_err(cs->dev, "bulk transfer failed (status %d)\n",
                        -status);
                /* That's all we can do. Communication problems
                   are handled by timeouts or network protocols. */
        }

        spin_lock_irqsave(&cs->lock, flags);
        if (!cs->connected) {
                pr_err("%s: disconnected\n", __func__);
        } else {
                cs->hw.usb->busy = 0;
                tasklet_schedule(&cs->write_tasklet);
        }
        spin_unlock_irqrestore(&cs->lock, flags);
}

static int send_cb(struct cardstate *cs)
{
        struct cmdbuf_t *cb = cs->cmdbuf;
        unsigned long flags;
        int count;
        int status = -ENOENT;
        struct usb_cardstate *ucs = cs->hw.usb;

        do {
                if (!cb->len) {
                        spin_lock_irqsave(&cs->cmdlock, flags);
                        cs->cmdbytes -= cs->curlen;
                        gig_dbg(DEBUG_OUTPUT, "send_cb: sent %u bytes, %u left",
                                cs->curlen, cs->cmdbytes);
                        cs->cmdbuf = cb->next;
                        if (cs->cmdbuf) {
                                cs->cmdbuf->prev = NULL;
                                cs->curlen = cs->cmdbuf->len;
                        } else {
                                cs->lastcmdbuf = NULL;
                                cs->curlen = 0;
                        }
                        spin_unlock_irqrestore(&cs->cmdlock, flags);

                        if (cb->wake_tasklet)
                                tasklet_schedule(cb->wake_tasklet);
                        kfree(cb);

                        cb = cs->cmdbuf;
                }

                if (cb) {
                        count = min(cb->len, ucs->bulk_out_size);
                        gig_dbg(DEBUG_OUTPUT, "send_cb: send %d bytes", count);

                        usb_fill_bulk_urb(ucs->bulk_out_urb, ucs->udev,
                                          usb_sndbulkpipe(ucs->udev,
                                                          ucs->bulk_out_epnum),
                                          cb->buf + cb->offset, count,
                                          gigaset_write_bulk_callback, cs);

                        cb->offset += count;
                        cb->len -= count;
                        ucs->busy = 1;

                        spin_lock_irqsave(&cs->lock, flags);
                        status = cs->connected ?
                                usb_submit_urb(ucs->bulk_out_urb, GFP_ATOMIC) :
                                -ENODEV;
                        spin_unlock_irqrestore(&cs->lock, flags);

                        if (status) {
                                ucs->busy = 0;
                                dev_err(cs->dev,
                                        "could not submit urb (error %d)\n",
                                        -status);
                                cb->len = 0; /* skip urb => remove cb+wakeup
                                                in next loop cycle */
                        }
                }
        } while (cb && status); /* next command on error */

        return status;
}

/* Send command to device. */
static int gigaset_write_cmd(struct cardstate *cs, struct cmdbuf_t *cb)
{
        unsigned long flags;
        int len;

        gigaset_dbg_buffer(cs->mstate != MS_LOCKED ?
                           DEBUG_TRANSCMD : DEBUG_LOCKCMD,
                           "CMD Transmit", cb->len, cb->buf);

        spin_lock_irqsave(&cs->cmdlock, flags);
        cb->prev = cs->lastcmdbuf;
        if (cs->lastcmdbuf)
                cs->lastcmdbuf->next = cb;
        else {
                cs->cmdbuf = cb;
                cs->curlen = cb->len;
        }
        cs->cmdbytes += cb->len;
        cs->lastcmdbuf = cb;
        spin_unlock_irqrestore(&cs->cmdlock, flags);

        spin_lock_irqsave(&cs->lock, flags);
        len = cb->len;
        if (cs->connected)
                tasklet_schedule(&cs->write_tasklet);
        spin_unlock_irqrestore(&cs->lock, flags);
        return len;
}

static int gigaset_write_room(struct cardstate *cs)
{
        unsigned bytes;

        bytes = cs->cmdbytes;
        return bytes < IF_WRITEBUF ? IF_WRITEBUF - bytes : 0;
}

static int gigaset_chars_in_buffer(struct cardstate *cs)
{
        return cs->cmdbytes;
}

/*
 * set the break characters on the internal serial adapter
 * using undocumented device commands reverse engineered from USB traces
 * of the Siemens Windows driver
 */
static int gigaset_brkchars(struct cardstate *cs, const unsigned char buf[6])
{
        struct usb_device *udev = cs->hw.usb->udev;

        gigaset_dbg_buffer(DEBUG_USBREQ, "brkchars", 6, buf);
        memcpy(cs->hw.usb->bchars, buf, 6);
        return usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x19, 0x41,
                               0, 0, &buf, 6, 2000);
}

static void gigaset_freebcshw(struct bc_state *bcs)
{
        /* unused */
}

/* Initialize the b-channel structure */
static int gigaset_initbcshw(struct bc_state *bcs)
{
        /* unused */
        bcs->hw.usb = NULL;
        return 0;
}

static void gigaset_reinitbcshw(struct bc_state *bcs)
{
        /* nothing to do for M10x */
}

static void gigaset_freecshw(struct cardstate *cs)
{
        tasklet_kill(&cs->write_tasklet);
        kfree(cs->hw.usb);
}

static int gigaset_initcshw(struct cardstate *cs)
{
        struct usb_cardstate *ucs;

        cs->hw.usb = ucs =
                kmalloc(sizeof(struct usb_cardstate), GFP_KERNEL);
        if (!ucs) {
                pr_err("out of memory\n");
                return -ENOMEM;
        }

        ucs->bchars[0] = 0;
        ucs->bchars[1] = 0;
        ucs->bchars[2] = 0;
        ucs->bchars[3] = 0;
        ucs->bchars[4] = 0x11;
        ucs->bchars[5] = 0x13;
        ucs->bulk_out_buffer = NULL;
        ucs->bulk_out_urb = NULL;
        ucs->read_urb = NULL;
        tasklet_init(&cs->write_tasklet,
                     gigaset_modem_fill, (unsigned long) cs);

        return 0;
}

/* Send data from current skb to the device. */
static int write_modem(struct cardstate *cs)
{
        int ret = 0;
        int count;
        struct bc_state *bcs = &cs->bcs[0]; /* only one channel */
        struct usb_cardstate *ucs = cs->hw.usb;
        unsigned long flags;

        gig_dbg(DEBUG_OUTPUT, "len: %d...", bcs->tx_skb->len);

        if (!bcs->tx_skb->len) {
                dev_kfree_skb_any(bcs->tx_skb);
                bcs->tx_skb = NULL;
                return -EINVAL;
        }

        /* Copy data to bulk out buffer and transmit data */
        count = min(bcs->tx_skb->len, (unsigned) ucs->bulk_out_size);
        skb_copy_from_linear_data(bcs->tx_skb, ucs->bulk_out_buffer, count);
        skb_pull(bcs->tx_skb, count);
        ucs->busy = 1;
        gig_dbg(DEBUG_OUTPUT, "write_modem: send %d bytes", count);

        spin_lock_irqsave(&cs->lock, flags);
        if (cs->connected) {
                usb_fill_bulk_urb(ucs->bulk_out_urb, ucs->udev,
                                  usb_sndbulkpipe(ucs->udev,
                                                  ucs->bulk_out_epnum),
                                  ucs->bulk_out_buffer, count,
                                  gigaset_write_bulk_callback, cs);
                ret = usb_submit_urb(ucs->bulk_out_urb, GFP_ATOMIC);
        } else {
                ret = -ENODEV;
        }
        spin_unlock_irqrestore(&cs->lock, flags);

        if (ret) {
                dev_err(cs->dev, "could not submit urb (error %d)\n", -ret);
                ucs->busy = 0;
        }

        if (!bcs->tx_skb->len) {
                /* skb sent completely */
                gigaset_skb_sent(bcs, bcs->tx_skb);

                gig_dbg(DEBUG_INTR, "kfree skb (Adr: %lx)!",
                        (unsigned long) bcs->tx_skb);
                dev_kfree_skb_any(bcs->tx_skb);
                bcs->tx_skb = NULL;
        }

        return ret;
}

static int gigaset_probe(struct usb_interface *interface,
                         const struct usb_device_id *id)
{
        int retval;
        struct usb_device *udev = interface_to_usbdev(interface);
        struct usb_host_interface *hostif = interface->cur_altsetting;
        struct cardstate *cs = NULL;
        struct usb_cardstate *ucs = NULL;
        struct usb_endpoint_descriptor *endpoint;
        int buffer_size;

        gig_dbg(DEBUG_ANY, "%s: Check if device matches ...", __func__);

        /* See if the device offered us matches what we can accept */
        if ((le16_to_cpu(udev->descriptor.idVendor)  != USB_M105_VENDOR_ID) ||
            (le16_to_cpu(udev->descriptor.idProduct) != USB_M105_PRODUCT_ID)) {
                gig_dbg(DEBUG_ANY, "device ID (0x%x, 0x%x) not for me - skip",
                        le16_to_cpu(udev->descriptor.idVendor),
                        le16_to_cpu(udev->descriptor.idProduct));
                return -ENODEV;
        }
        if (hostif->desc.bInterfaceNumber != 0) {
                gig_dbg(DEBUG_ANY, "interface %d not for me - skip",
                        hostif->desc.bInterfaceNumber);
                return -ENODEV;
        }
        if (hostif->desc.bAlternateSetting != 0) {
                dev_notice(&udev->dev, "unsupported altsetting %d - skip",
                           hostif->desc.bAlternateSetting);
                return -ENODEV;
        }
        if (hostif->desc.bInterfaceClass != 255) {
                dev_notice(&udev->dev, "unsupported interface class %d - skip",
                           hostif->desc.bInterfaceClass);
                return -ENODEV;
        }

        dev_info(&udev->dev, "%s: Device matched ... !\n", __func__);

        /* allocate memory for our device state and initialize it */
        cs = gigaset_initcs(driver, 1, 1, 0, cidmode, GIGASET_MODULENAME);
        if (!cs)
                return -ENODEV;
        ucs = cs->hw.usb;

        /* save off device structure ptrs for later use */
        usb_get_dev(udev);
        ucs->udev = udev;
        ucs->interface = interface;
        cs->dev = &interface->dev;

        /* save address of controller structure */
        usb_set_intfdata(interface, cs);

        endpoint = &hostif->endpoint[0].desc;

        buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
        ucs->bulk_out_size = buffer_size;
        ucs->bulk_out_epnum = usb_endpoint_num(endpoint);
        ucs->bulk_out_buffer = kmalloc(buffer_size, GFP_KERNEL);
        if (!ucs->bulk_out_buffer) {
                dev_err(cs->dev, "Couldn't allocate bulk_out_buffer\n");
                retval = -ENOMEM;
                goto error;
        }

        ucs->bulk_out_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!ucs->bulk_out_urb) {
                dev_err(cs->dev, "Couldn't allocate bulk_out_urb\n");
                retval = -ENOMEM;
                goto error;
        }

        endpoint = &hostif->endpoint[1].desc;

        ucs->busy = 0;

        ucs->read_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!ucs->read_urb) {
                dev_err(cs->dev, "No free urbs available\n");
                retval = -ENOMEM;
                goto error;
        }
        buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
        ucs->rcvbuf_size = buffer_size;
        ucs->rcvbuf = kmalloc(buffer_size, GFP_KERNEL);
        if (!ucs->rcvbuf) {
                dev_err(cs->dev, "Couldn't allocate rcvbuf\n");
                retval = -ENOMEM;
                goto error;
        }
        /* Fill the interrupt urb and send it to the core */
        usb_fill_int_urb(ucs->read_urb, udev,
                         usb_rcvintpipe(udev, usb_endpoint_num(endpoint)),
                         ucs->rcvbuf, buffer_size,
                         gigaset_read_int_callback,
                         cs, endpoint->bInterval);

        retval = usb_submit_urb(ucs->read_urb, GFP_KERNEL);
        if (retval) {
                dev_err(cs->dev, "Could not submit URB (error %d)\n", -retval);
                goto error;
        }

        /* tell common part that the device is ready */
        if (startmode == SM_LOCKED)
                cs->mstate = MS_LOCKED;

        retval = gigaset_start(cs);
        if (retval < 0) {
                tasklet_kill(&cs->write_tasklet);
                goto error;
        }
        return 0;

error:
        usb_kill_urb(ucs->read_urb);
        kfree(ucs->bulk_out_buffer);
        usb_free_urb(ucs->bulk_out_urb);
        kfree(ucs->rcvbuf);
        usb_free_urb(ucs->read_urb);
        usb_set_intfdata(interface, NULL);
        ucs->read_urb = ucs->bulk_out_urb = NULL;
        ucs->rcvbuf = ucs->bulk_out_buffer = NULL;
        usb_put_dev(ucs->udev);
        ucs->udev = NULL;
        ucs->interface = NULL;
        gigaset_freecs(cs);
        return retval;
}

static void gigaset_disconnect(struct usb_interface *interface)
{
        struct cardstate *cs;
        struct usb_cardstate *ucs;

        cs = usb_get_intfdata(interface);
        ucs = cs->hw.usb;

        dev_info(cs->dev, "disconnecting Gigaset USB adapter\n");

        usb_kill_urb(ucs->read_urb);

        gigaset_stop(cs);

        usb_set_intfdata(interface, NULL);
        tasklet_kill(&cs->write_tasklet);

        usb_kill_urb(ucs->bulk_out_urb);

        kfree(ucs->bulk_out_buffer);
        usb_free_urb(ucs->bulk_out_urb);
        kfree(ucs->rcvbuf);
        usb_free_urb(ucs->read_urb);
        ucs->read_urb = ucs->bulk_out_urb = NULL;
        ucs->rcvbuf = ucs->bulk_out_buffer = NULL;

        usb_put_dev(ucs->udev);
        ucs->interface = NULL;
        ucs->udev = NULL;
        cs->dev = NULL;
        gigaset_freecs(cs);
}

/* gigaset_suspend
 * This function is called before the USB connection is suspended or reset.
 */
static int gigaset_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct cardstate *cs = usb_get_intfdata(intf);

        /* stop activity */
        cs->connected = 0;      /* prevent rescheduling */
        usb_kill_urb(cs->hw.usb->read_urb);
        tasklet_kill(&cs->write_tasklet);
        usb_kill_urb(cs->hw.usb->bulk_out_urb);

        gig_dbg(DEBUG_SUSPEND, "suspend complete");
        return 0;
}

/* gigaset_resume
 * This function is called after the USB connection has been resumed or reset.
 */
static int gigaset_resume(struct usb_interface *intf)
{
        struct cardstate *cs = usb_get_intfdata(intf);
        int rc;

        /* resubmit interrupt URB */
        cs->connected = 1;
        rc = usb_submit_urb(cs->hw.usb->read_urb, GFP_KERNEL);
        if (rc) {
                dev_err(cs->dev, "Could not submit read URB (error %d)\n", -rc);
                return rc;
        }

        gig_dbg(DEBUG_SUSPEND, "resume complete");
        return 0;
}

/* gigaset_pre_reset
 * This function is called before the USB connection is reset.
 */
static int gigaset_pre_reset(struct usb_interface *intf)
{
        /* same as suspend */
        return gigaset_suspend(intf, PMSG_ON);
}

static const struct gigaset_ops ops = {
        gigaset_write_cmd,
        gigaset_write_room,
        gigaset_chars_in_buffer,
        gigaset_brkchars,
        gigaset_init_bchannel,
        gigaset_close_bchannel,
        gigaset_initbcshw,
        gigaset_freebcshw,
        gigaset_reinitbcshw,
        gigaset_initcshw,
        gigaset_freecshw,
        gigaset_set_modem_ctrl,
        gigaset_baud_rate,
        gigaset_set_line_ctrl,
        gigaset_m10x_send_skb,
        gigaset_m10x_input,
};

/*
 * This function is called while kernel-module is loaded
 */
static int __init usb_gigaset_init(void)
{
        int result;

        /* allocate memory for our driver state and initialize it */
        driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
                                    GIGASET_MODULENAME, GIGASET_DEVNAME,
                                    &ops, THIS_MODULE);
        if (driver == NULL) {
                result = -ENOMEM;
                goto error;
        }

        /* register this driver with the USB subsystem */
        result = usb_register(&gigaset_usb_driver);
        if (result < 0) {
                pr_err("error %d registering USB driver\n", -result);
                goto error;
        }

        pr_info(DRIVER_DESC "\n");
        return 0;

error:
        if (driver)
                gigaset_freedriver(driver);
        driver = NULL;
        return result;
}

/*
 * This function is called while unloading the kernel-module
 */
static void __exit usb_gigaset_exit(void)
{
        int i;

        gigaset_blockdriver(driver); /* => probe will fail
                                      * => no gigaset_start any more
                                      */

        /* stop all connected devices */
        for (i = 0; i < driver->minors; i++)
                gigaset_shutdown(driver->cs + i);

        /* from now on, no isdn callback should be possible */

        /* deregister this driver with the USB subsystem */
        usb_deregister(&gigaset_usb_driver);
        /* this will call the disconnect-callback */
        /* from now on, no disconnect/probe callback should be running */

        gigaset_freedriver(driver);
        driver = NULL;
}


module_init(usb_gigaset_init);
module_exit(usb_gigaset_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);

MODULE_LICENSE("GPL");