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bas-gigaset.c

/*
 * USB driver for Gigaset 307x base via direct USB connection.
 *
 * Copyright (c) 2001 by Hansjoerg Lipp <hjlipp@web.de>,
 *                       Tilman Schmidt <tilman@imap.cc>,
 *                       Stefan Eilers.
 *
 * =====================================================================
 *    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/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/usb.h>
#include <linux/module.h>
#include <linux/moduleparam.h>

/* Version Information */
#define DRIVER_AUTHOR "Tilman Schmidt <tilman@imap.cc>, Hansjoerg Lipp <hjlipp@web.de>, Stefan Eilers"
#define DRIVER_DESC "USB Driver for Gigaset 307x"


/* 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      16
#define GIGASET_MODULENAME "bas_gigaset"
#define GIGASET_DEVNAME    "ttyGB"

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

/* Values for the Gigaset 307x */
#define USB_GIGA_VENDOR_ID      0x0681
#define USB_3070_PRODUCT_ID     0x0001
#define USB_3075_PRODUCT_ID     0x0002
#define USB_SX303_PRODUCT_ID    0x0021
#define USB_SX353_PRODUCT_ID    0x0022

/* table of devices that work with this driver */
static const struct usb_device_id gigaset_table [] = {
      { USB_DEVICE(USB_GIGA_VENDOR_ID, USB_3070_PRODUCT_ID) },
      { USB_DEVICE(USB_GIGA_VENDOR_ID, USB_3075_PRODUCT_ID) },
      { USB_DEVICE(USB_GIGA_VENDOR_ID, USB_SX303_PRODUCT_ID) },
      { USB_DEVICE(USB_GIGA_VENDOR_ID, USB_SX353_PRODUCT_ID) },
      { } /* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, gigaset_table);

/*======================= local function prototypes ==========================*/

/* function called if a new device belonging to this driver is connected */
static int gigaset_probe(struct usb_interface *interface,
                   const struct usb_device_id *id);

/* Function will be called if the device is unplugged */
static void gigaset_disconnect(struct usb_interface *interface);

static int atread_submit(struct cardstate *, int);
static void stopurbs(struct bas_bc_state *);
static int req_submit(struct bc_state *, int, int, int);
static int atwrite_submit(struct cardstate *, unsigned char *, int);
static int start_cbsend(struct cardstate *);

/*============================================================================*/

struct bas_cardstate {
      struct usb_device *udev;            /* USB device pointer */
      struct usb_interface    *interface; /* interface for this device */
      unsigned char           minor;            /* starting minor number */

      struct urb        *urb_ctrl;  /* control pipe default URB */
      struct usb_ctrlrequest  dr_ctrl;
      struct timer_list timer_ctrl; /* control request timeout */
      int               retry_ctrl;

      struct timer_list timer_atrdy;      /* AT command ready timeout */
      struct urb        *urb_cmd_out;     /* for sending AT commands */
      struct usb_ctrlrequest  dr_cmd_out;
      int               retry_cmd_out;

      struct urb        *urb_cmd_in;      /* for receiving AT replies */
      struct usb_ctrlrequest  dr_cmd_in;
      struct timer_list timer_cmd_in;     /* receive request timeout */
      unsigned char           *rcvbuf;    /* AT reply receive buffer */

      struct urb        *urb_int_in;      /* URB for interrupt pipe */
      unsigned char           int_in_buf[3];

      spinlock_t        lock;       /* locks all following */
      atomic_t          basstate;   /* bitmap (BS_*) */
      int               pending;    /* uncompleted base request */
      int               rcvbuf_size;      /* size of AT receive buffer */
                                    /* 0: no receive in progress */
      int               retry_cmd_in;     /* receive req retry count */
};

/* status of direct USB connection to 307x base (bits in basstate) */
#define BS_ATOPEN 0x001 /* AT channel open */
#define BS_B1OPEN 0x002 /* B channel 1 open */
#define BS_B2OPEN 0x004 /* B channel 2 open */
#define BS_ATREADY      0x008 /* base ready for AT command */
#define BS_INIT         0x010 /* base has signalled INIT_OK */
#define BS_ATTIMER      0x020 /* waiting for HD_READY_SEND_ATDATA */
#define BS_ATRDPEND     0x040 /* urb_cmd_in in use */
#define BS_ATWRPEND     0x080 /* urb_cmd_out in use */


static struct gigaset_driver *driver = NULL;
static struct cardstate *cardstate = NULL;

/* 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,
};

/* get message text for usb_submit_urb return code
 */
static char *get_usb_rcmsg(int rc)
{
      static char unkmsg[28];

      switch (rc) {
      case 0:
            return "success";
      case -ENOMEM:
            return "out of memory";
      case -ENODEV:
            return "device not present";
      case -ENOENT:
            return "endpoint not present";
      case -ENXIO:
            return "URB type not supported";
      case -EINVAL:
            return "invalid argument";
      case -EAGAIN:
            return "start frame too early or too much scheduled";
      case -EFBIG:
            return "too many isochronous frames requested";
      case -EPIPE:
            return "endpoint stalled";
      case -EMSGSIZE:
            return "invalid packet size";
      case -ENOSPC:
            return "would overcommit USB bandwidth";
      case -ESHUTDOWN:
            return "device shut down";
      case -EPERM:
            return "reject flag set";
      case -EHOSTUNREACH:
            return "device suspended";
      default:
            snprintf(unkmsg, sizeof(unkmsg), "unknown error %d", rc);
            return unkmsg;
      }
}

/* get message text for USB status code
 */
static char *get_usb_statmsg(int status)
{
      static char unkmsg[28];

      switch (status) {
      case 0:
            return "success";
      case -ENOENT:
            return "unlinked (sync)";
      case -EINPROGRESS:
            return "pending";
      case -EPROTO:
            return "bit stuffing error, timeout, or unknown USB error";
      case -EILSEQ:
            return "CRC mismatch, timeout, or unknown USB error";
      case -ETIME:
            return "timed out";
      case -EPIPE:
            return "endpoint stalled";
      case -ECOMM:
            return "IN buffer overrun";
      case -ENOSR:
            return "OUT buffer underrun";
      case -EOVERFLOW:
            return "too much data";
      case -EREMOTEIO:
            return "short packet detected";
      case -ENODEV:
            return "device removed";
      case -EXDEV:
            return "partial isochronous transfer";
      case -EINVAL:
            return "invalid argument";
      case -ECONNRESET:
            return "unlinked (async)";
      case -ESHUTDOWN:
            return "device shut down";
      default:
            snprintf(unkmsg, sizeof(unkmsg), "unknown status %d", status);
            return unkmsg;
      }
}

/* usb_pipetype_str
 * retrieve string representation of USB pipe type
 */
static inline char *usb_pipetype_str(int pipe)
{
      if (usb_pipeisoc(pipe))
            return "Isoc";
      if (usb_pipeint(pipe))
            return "Int";
      if (usb_pipecontrol(pipe))
            return "Ctrl";
      if (usb_pipebulk(pipe))
            return "Bulk";
      return "?";
}

/* dump_urb
 * write content of URB to syslog for debugging
 */
static inline void dump_urb(enum debuglevel level, const char *tag,
                      struct urb *urb)
{
#ifdef CONFIG_GIGASET_DEBUG
      int i;
      gig_dbg(level, "%s urb(0x%08lx)->{", tag, (unsigned long) urb);
      if (urb) {
            gig_dbg(level,
                  "  dev=0x%08lx, pipe=%s:EP%d/DV%d:%s, "
                  "status=%d, hcpriv=0x%08lx, transfer_flags=0x%x,",
                  (unsigned long) urb->dev,
                  usb_pipetype_str(urb->pipe),
                  usb_pipeendpoint(urb->pipe), usb_pipedevice(urb->pipe),
                  usb_pipein(urb->pipe) ? "in" : "out",
                  urb->status, (unsigned long) urb->hcpriv,
                  urb->transfer_flags);
            gig_dbg(level,
                  "  transfer_buffer=0x%08lx[%d], actual_length=%d, "
                  "setup_packet=0x%08lx,",
                  (unsigned long) urb->transfer_buffer,
                  urb->transfer_buffer_length, urb->actual_length,
                  (unsigned long) urb->setup_packet);
            gig_dbg(level,
                  "  start_frame=%d, number_of_packets=%d, interval=%d, "
                  "error_count=%d,",
                  urb->start_frame, urb->number_of_packets, urb->interval,
                  urb->error_count);
            gig_dbg(level,
                  "  context=0x%08lx, complete=0x%08lx, "
                  "iso_frame_desc[]={",
                  (unsigned long) urb->context,
                  (unsigned long) urb->complete);
            for (i = 0; i < urb->number_of_packets; i++) {
                  struct usb_iso_packet_descriptor *pifd
                        = &urb->iso_frame_desc[i];
                  gig_dbg(level,
                        "    {offset=%u, length=%u, actual_length=%u, "
                        "status=%u}",
                        pifd->offset, pifd->length, pifd->actual_length,
                        pifd->status);
            }
      }
      gig_dbg(level, "}}");
#endif
}

/* read/set modem control bits etc. (m10x only) */
static int gigaset_set_modem_ctrl(struct cardstate *cs, unsigned old_state,
                          unsigned new_state)
{
      return -EINVAL;
}

static int gigaset_baud_rate(struct cardstate *cs, unsigned cflag)
{
      return -EINVAL;
}

static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
{
      return -EINVAL;
}

/* error_hangup
 * hang up any existing connection because of an unrecoverable error
 * This function may be called from any context and takes care of scheduling
 * the necessary actions for execution outside of interrupt context.
 * cs->lock must not be held.
 * argument:
 *    B channel control structure
 */
static inline void error_hangup(struct bc_state *bcs)
{
      struct cardstate *cs = bcs->cs;

      gig_dbg(DEBUG_ANY, "%s: scheduling HUP for channel %d",
            __func__, bcs->channel);

      if (!gigaset_add_event(cs, &bcs->at_state, EV_HUP, NULL, 0, NULL))
            dev_err(cs->dev, "event queue full\n");

      gigaset_schedule_event(cs);
}

/* error_reset
 * reset Gigaset device because of an unrecoverable error
 * This function may be called from any context, and takes care of
 * scheduling the necessary actions for execution outside of interrupt context.
 * cs->lock must not be held.
 * argument:
 *    controller state structure
 */
static inline void error_reset(struct cardstate *cs)
{
      /* close AT command channel to recover (ignore errors) */
      req_submit(cs->bcs, HD_CLOSE_ATCHANNEL, 0, BAS_TIMEOUT);

      //FIXME try to recover without bothering the user
      dev_err(cs->dev,
          "unrecoverable error - please disconnect Gigaset base to reset\n");
}

/* check_pending
 * check for completion of pending control request
 * parameter:
 *    ucs   hardware specific controller state structure
 */
static void check_pending(struct bas_cardstate *ucs)
{
      unsigned long flags;

      spin_lock_irqsave(&ucs->lock, flags);
      switch (ucs->pending) {
      case 0:
            break;
      case HD_OPEN_ATCHANNEL:
            if (atomic_read(&ucs->basstate) & BS_ATOPEN)
                  ucs->pending = 0;
            break;
      case HD_OPEN_B1CHANNEL:
            if (atomic_read(&ucs->basstate) & BS_B1OPEN)
                  ucs->pending = 0;
            break;
      case HD_OPEN_B2CHANNEL:
            if (atomic_read(&ucs->basstate) & BS_B2OPEN)
                  ucs->pending = 0;
            break;
      case HD_CLOSE_ATCHANNEL:
            if (!(atomic_read(&ucs->basstate) & BS_ATOPEN))
                  ucs->pending = 0;
            break;
      case HD_CLOSE_B1CHANNEL:
            if (!(atomic_read(&ucs->basstate) & BS_B1OPEN))
                  ucs->pending = 0;
            break;
      case HD_CLOSE_B2CHANNEL:
            if (!(atomic_read(&ucs->basstate) & BS_B2OPEN))
                  ucs->pending = 0;
            break;
      case HD_DEVICE_INIT_ACK:            /* no reply expected */
            ucs->pending = 0;
            break;
      /* HD_READ_ATMESSAGE, HD_WRITE_ATMESSAGE, HD_RESET_INTERRUPTPIPE
       * are handled separately and should never end up here
       */
      default:
            dev_warn(&ucs->interface->dev,
                   "unknown pending request 0x%02x cleared\n",
                   ucs->pending);
            ucs->pending = 0;
      }

      if (!ucs->pending)
            del_timer(&ucs->timer_ctrl);

      spin_unlock_irqrestore(&ucs->lock, flags);
}

/* cmd_in_timeout
 * timeout routine for command input request
 * argument:
 *    controller state structure
 */
static void cmd_in_timeout(unsigned long data)
{
      struct cardstate *cs = (struct cardstate *) data;
      struct bas_cardstate *ucs = cs->hw.bas;
      int rc;

      if (!ucs->rcvbuf_size) {
            gig_dbg(DEBUG_USBREQ, "%s: no receive in progress", __func__);
            return;
      }

      if (ucs->retry_cmd_in++ < BAS_RETRY) {
            dev_notice(cs->dev, "control read: timeout, retry %d\n",
                     ucs->retry_cmd_in);
            rc = atread_submit(cs, BAS_TIMEOUT);
            if (rc >= 0 || rc == -ENODEV)
                  /* resubmitted or disconnected */
                  /* - bypass regular exit block */
                  return;
      } else {
            dev_err(cs->dev,
                  "control read: timeout, giving up after %d tries\n",
                  ucs->retry_cmd_in);
      }
      kfree(ucs->rcvbuf);
      ucs->rcvbuf = NULL;
      ucs->rcvbuf_size = 0;
      error_reset(cs);
}

/* set/clear bits in base connection state, return previous state
 */
inline static int update_basstate(struct bas_cardstate *ucs,
                          int set, int clear)
{
      unsigned long flags;
      int state;

      spin_lock_irqsave(&ucs->lock, flags);
      state = atomic_read(&ucs->basstate);
      atomic_set(&ucs->basstate, (state & ~clear) | set);
      spin_unlock_irqrestore(&ucs->lock, flags);
      return state;
}

/* read_ctrl_callback
 * USB completion handler for control pipe input
 * called by the USB subsystem in interrupt context
 * parameter:
 *    urb   USB request block
 *          urb->context = inbuf structure for controller state
 */
static void read_ctrl_callback(struct urb *urb)
{
      struct inbuf_t *inbuf = urb->context;
      struct cardstate *cs = inbuf->cs;
      struct bas_cardstate *ucs = cs->hw.bas;
      int have_data = 0;
      unsigned numbytes;
      int rc;

      update_basstate(ucs, 0, BS_ATRDPEND);

      if (!ucs->rcvbuf_size) {
            dev_warn(cs->dev, "%s: no receive in progress\n", __func__);
            return;
      }

      del_timer(&ucs->timer_cmd_in);

      switch (urb->status) {
      case 0:                       /* normal completion */
            numbytes = urb->actual_length;
            if (unlikely(numbytes != ucs->rcvbuf_size)) {
                  dev_warn(cs->dev,
                         "control read: received %d chars, expected %d\n",
                         numbytes, ucs->rcvbuf_size);
                  if (numbytes > ucs->rcvbuf_size)
                        numbytes = ucs->rcvbuf_size;
            }

            /* copy received bytes to inbuf */
            have_data = gigaset_fill_inbuf(inbuf, ucs->rcvbuf, numbytes);

            if (unlikely(numbytes < ucs->rcvbuf_size)) {
                  /* incomplete - resubmit for remaining bytes */
                  ucs->rcvbuf_size -= numbytes;
                  ucs->retry_cmd_in = 0;
                  rc = atread_submit(cs, BAS_TIMEOUT);
                  if (rc >= 0 || rc == -ENODEV)
                        /* resubmitted or disconnected */
                        /* - bypass regular exit block */
                        return;
                  error_reset(cs);
            }
            break;

      case -ENOENT:                 /* cancelled */
      case -ECONNRESET:       /* cancelled (async) */
      case -EINPROGRESS:            /* pending */
      case -ENODEV:                 /* device removed */
      case -ESHUTDOWN:        /* device shut down */
            /* no action necessary */
            gig_dbg(DEBUG_USBREQ, "%s: %s",
                  __func__, get_usb_statmsg(urb->status));
            break;

      default:                /* severe trouble */
            dev_warn(cs->dev, "control read: %s\n",
                   get_usb_statmsg(urb->status));
            if (ucs->retry_cmd_in++ < BAS_RETRY) {
                  dev_notice(cs->dev, "control read: retry %d\n",
                           ucs->retry_cmd_in);
                  rc = atread_submit(cs, BAS_TIMEOUT);
                  if (rc >= 0 || rc == -ENODEV)
                        /* resubmitted or disconnected */
                        /* - bypass regular exit block */
                        return;
            } else {
                  dev_err(cs->dev,
                        "control read: giving up after %d tries\n",
                        ucs->retry_cmd_in);
            }
            error_reset(cs);
      }

      kfree(ucs->rcvbuf);
      ucs->rcvbuf = NULL;
      ucs->rcvbuf_size = 0;
      if (have_data) {
            gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
            gigaset_schedule_event(cs);
      }
}

/* atread_submit
 * submit an HD_READ_ATMESSAGE command URB and optionally start a timeout
 * parameters:
 *    cs    controller state structure
 *    timeout     timeout in 1/10 sec., 0: none
 * return value:
 *    0 on success
 *    -EBUSY if another request is pending
 *    any URB submission error code
 */
static int atread_submit(struct cardstate *cs, int timeout)
{
      struct bas_cardstate *ucs = cs->hw.bas;
      int ret;

      gig_dbg(DEBUG_USBREQ, "-------> HD_READ_ATMESSAGE (%d)",
            ucs->rcvbuf_size);

      if (update_basstate(ucs, BS_ATRDPEND, 0) & BS_ATRDPEND) {
            dev_err(cs->dev,
                  "could not submit HD_READ_ATMESSAGE: URB busy\n");
            return -EBUSY;
      }

      ucs->dr_cmd_in.bRequestType = IN_VENDOR_REQ;
      ucs->dr_cmd_in.bRequest = HD_READ_ATMESSAGE;
      ucs->dr_cmd_in.wValue = 0;
      ucs->dr_cmd_in.wIndex = 0;
      ucs->dr_cmd_in.wLength = cpu_to_le16(ucs->rcvbuf_size);
      usb_fill_control_urb(ucs->urb_cmd_in, ucs->udev,
                       usb_rcvctrlpipe(ucs->udev, 0),
                       (unsigned char*) & ucs->dr_cmd_in,
                       ucs->rcvbuf, ucs->rcvbuf_size,
                       read_ctrl_callback, cs->inbuf);

      if ((ret = usb_submit_urb(ucs->urb_cmd_in, GFP_ATOMIC)) != 0) {
            update_basstate(ucs, 0, BS_ATRDPEND);
            dev_err(cs->dev, "could not submit HD_READ_ATMESSAGE: %s\n",
                  get_usb_rcmsg(ret));
            return ret;
      }

      if (timeout > 0) {
            gig_dbg(DEBUG_USBREQ, "setting timeout of %d/10 secs", timeout);
            ucs->timer_cmd_in.expires = jiffies + timeout * HZ / 10;
            ucs->timer_cmd_in.data = (unsigned long) cs;
            ucs->timer_cmd_in.function = cmd_in_timeout;
            add_timer(&ucs->timer_cmd_in);
      }
      return 0;
}

/* read_int_callback
 * USB completion handler for interrupt pipe input
 * called by the USB subsystem in interrupt context
 * parameter:
 *    urb   USB request block
 *          urb->context = controller state structure
 */
static void read_int_callback(struct urb *urb)
{
      struct cardstate *cs = urb->context;
      struct bas_cardstate *ucs = cs->hw.bas;
      struct bc_state *bcs;
      unsigned long flags;
      int rc;
      unsigned l;
      int channel;

      switch (urb->status) {
      case 0:                 /* success */
            break;
      case -ENOENT:                 /* cancelled */
      case -ECONNRESET:       /* cancelled (async) */
      case -EINPROGRESS:            /* pending */
            /* ignore silently */
            gig_dbg(DEBUG_USBREQ, "%s: %s",
                  __func__, get_usb_statmsg(urb->status));
            return;
      case -ENODEV:                 /* device removed */
      case -ESHUTDOWN:        /* device shut down */
            //FIXME use this as disconnect indicator?
            gig_dbg(DEBUG_USBREQ, "%s: device disconnected", __func__);
            return;
      default:          /* severe trouble */
            dev_warn(cs->dev, "interrupt read: %s\n",
                   get_usb_statmsg(urb->status));
            //FIXME corrective action? resubmission always ok?
            goto resubmit;
      }

      /* drop incomplete packets even if the missing bytes wouldn't matter */
      if (unlikely(urb->actual_length < 3)) {
            dev_warn(cs->dev, "incomplete interrupt packet (%d bytes)\n",
                   urb->actual_length);
            goto resubmit;
      }

      l = (unsigned) ucs->int_in_buf[1] +
          (((unsigned) ucs->int_in_buf[2]) << 8);

      gig_dbg(DEBUG_USBREQ, "<-------%d: 0x%02x (%u [0x%02x 0x%02x])",
            urb->actual_length, (int)ucs->int_in_buf[0], l,
            (int)ucs->int_in_buf[1], (int)ucs->int_in_buf[2]);

      channel = 0;

      switch (ucs->int_in_buf[0]) {
      case HD_DEVICE_INIT_OK:
            update_basstate(ucs, BS_INIT, 0);
            break;

      case HD_READY_SEND_ATDATA:
            del_timer(&ucs->timer_atrdy);
            update_basstate(ucs, BS_ATREADY, BS_ATTIMER);
            start_cbsend(cs);
            break;

      case HD_OPEN_B2CHANNEL_ACK:
            ++channel;
      case HD_OPEN_B1CHANNEL_ACK:
            bcs = cs->bcs + channel;
            update_basstate(ucs, BS_B1OPEN << channel, 0);
            gigaset_bchannel_up(bcs);
            break;

      case HD_OPEN_ATCHANNEL_ACK:
            update_basstate(ucs, BS_ATOPEN, 0);
            start_cbsend(cs);
            break;

      case HD_CLOSE_B2CHANNEL_ACK:
            ++channel;
      case HD_CLOSE_B1CHANNEL_ACK:
            bcs = cs->bcs + channel;
            update_basstate(ucs, 0, BS_B1OPEN << channel);
            stopurbs(bcs->hw.bas);
            gigaset_bchannel_down(bcs);
            break;

      case HD_CLOSE_ATCHANNEL_ACK:
            update_basstate(ucs, 0, BS_ATOPEN);
            break;

      case HD_B2_FLOW_CONTROL:
            ++channel;
      case HD_B1_FLOW_CONTROL:
            bcs = cs->bcs + channel;
            atomic_add((l - BAS_NORMFRAME) * BAS_CORRFRAMES,
                     &bcs->hw.bas->corrbytes);
            gig_dbg(DEBUG_ISO,
                  "Flow control (channel %d, sub %d): 0x%02x => %d",
                  channel, bcs->hw.bas->numsub, l,
                  atomic_read(&bcs->hw.bas->corrbytes));
            break;

      case HD_RECEIVEATDATA_ACK:    /* AT response ready to be received */
            if (!l) {
                  dev_warn(cs->dev,
                        "HD_RECEIVEATDATA_ACK with length 0 ignored\n");
                  break;
            }
            spin_lock_irqsave(&cs->lock, flags);
            if (ucs->rcvbuf_size) {
                  /* throw away previous buffer - we have no queue */
                  dev_err(cs->dev,
                        "receive AT data overrun, %d bytes lost\n",
                        ucs->rcvbuf_size);
                  kfree(ucs->rcvbuf);
                  ucs->rcvbuf_size = 0;
            }
            if ((ucs->rcvbuf = kmalloc(l, GFP_ATOMIC)) == NULL) {
                  spin_unlock_irqrestore(&cs->lock, flags);
                  dev_err(cs->dev, "out of memory receiving AT data\n");
                  error_reset(cs);
                  break;
            }
            ucs->rcvbuf_size = l;
            ucs->retry_cmd_in = 0;
            if ((rc = atread_submit(cs, BAS_TIMEOUT)) < 0) {
                  kfree(ucs->rcvbuf);
                  ucs->rcvbuf = NULL;
                  ucs->rcvbuf_size = 0;
                  if (rc != -ENODEV) {
                        //FIXME corrective action?
                        spin_unlock_irqrestore(&cs->lock, flags);
                        error_reset(cs);
                        break;
                  }
            }
            spin_unlock_irqrestore(&cs->lock, flags);
            break;

      case HD_RESET_INTERRUPT_PIPE_ACK:
            gig_dbg(DEBUG_USBREQ, "HD_RESET_INTERRUPT_PIPE_ACK");
            break;

      case HD_SUSPEND_END:
            gig_dbg(DEBUG_USBREQ, "HD_SUSPEND_END");
            break;

      default:
            dev_warn(cs->dev,
                   "unknown Gigaset signal 0x%02x (%u) ignored\n",
                   (int) ucs->int_in_buf[0], l);
      }

      check_pending(ucs);

resubmit:
      rc = usb_submit_urb(urb, GFP_ATOMIC);
      if (unlikely(rc != 0 && rc != -ENODEV)) {
            dev_err(cs->dev, "could not resubmit interrupt URB: %s\n",
                  get_usb_rcmsg(rc));
            error_reset(cs);
      }
}

/* read_iso_callback
 * USB completion handler for B channel isochronous input
 * called by the USB subsystem in interrupt context
 * parameter:
 *    urb   USB request block of completed request
 *          urb->context = bc_state structure
 */
static void read_iso_callback(struct urb *urb)
{
      struct bc_state *bcs;
      struct bas_bc_state *ubc;
      unsigned long flags;
      int i, rc;

      /* status codes not worth bothering the tasklet with */
      if (unlikely(urb->status == -ENOENT ||
                 urb->status == -ECONNRESET ||
                 urb->status == -EINPROGRESS ||
                 urb->status == -ENODEV ||
                 urb->status == -ESHUTDOWN)) {
            gig_dbg(DEBUG_ISO, "%s: %s",
                  __func__, get_usb_statmsg(urb->status));
            return;
      }

      bcs = urb->context;
      ubc = bcs->hw.bas;

      spin_lock_irqsave(&ubc->isoinlock, flags);
      if (likely(ubc->isoindone == NULL)) {
            /* pass URB to tasklet */
            ubc->isoindone = urb;
            tasklet_schedule(&ubc->rcvd_tasklet);
      } else {
            /* tasklet still busy, drop data and resubmit URB */
            ubc->loststatus = urb->status;
            for (i = 0; i < BAS_NUMFRAMES; i++) {
                  ubc->isoinlost += urb->iso_frame_desc[i].actual_length;
                  if (unlikely(urb->iso_frame_desc[i].status != 0 &&
                             urb->iso_frame_desc[i].status !=
                                                -EINPROGRESS))
                        ubc->loststatus = urb->iso_frame_desc[i].status;
                  urb->iso_frame_desc[i].status = 0;
                  urb->iso_frame_desc[i].actual_length = 0;
            }
            if (likely(atomic_read(&ubc->running))) {
                  /* urb->dev is clobbered by USB subsystem */
                  urb->dev = bcs->cs->hw.bas->udev;
                  urb->transfer_flags = URB_ISO_ASAP;
                  urb->number_of_packets = BAS_NUMFRAMES;
                  gig_dbg(DEBUG_ISO, "%s: isoc read overrun/resubmit",
                        __func__);
                  rc = usb_submit_urb(urb, GFP_ATOMIC);
                  if (unlikely(rc != 0 && rc != -ENODEV)) {
                        dev_err(bcs->cs->dev,
                              "could not resubmit isochronous read "
                              "URB: %s\n", get_usb_rcmsg(rc));
                        dump_urb(DEBUG_ISO, "isoc read", urb);
                        error_hangup(bcs);
                  }
            }
      }
      spin_unlock_irqrestore(&ubc->isoinlock, flags);
}

/* write_iso_callback
 * USB completion handler for B channel isochronous output
 * called by the USB subsystem in interrupt context
 * parameter:
 *    urb   USB request block of completed request
 *          urb->context = isow_urbctx_t structure
 */
static void write_iso_callback(struct urb *urb)
{
      struct isow_urbctx_t *ucx;
      struct bas_bc_state *ubc;
      unsigned long flags;

      /* status codes not worth bothering the tasklet with */
      if (unlikely(urb->status == -ENOENT ||
                 urb->status == -ECONNRESET ||
                 urb->status == -EINPROGRESS ||
                 urb->status == -ENODEV ||
                 urb->status == -ESHUTDOWN)) {
            gig_dbg(DEBUG_ISO, "%s: %s",
                  __func__, get_usb_statmsg(urb->status));
            return;
      }

      /* pass URB context to tasklet */
      ucx = urb->context;
      ubc = ucx->bcs->hw.bas;

      spin_lock_irqsave(&ubc->isooutlock, flags);
      ubc->isooutovfl = ubc->isooutdone;
      ubc->isooutdone = ucx;
      spin_unlock_irqrestore(&ubc->isooutlock, flags);
      tasklet_schedule(&ubc->sent_tasklet);
}

/* starturbs
 * prepare and submit USB request blocks for isochronous input and output
 * argument:
 *    B channel control structure
 * return value:
 *    0 on success
 *    < 0 on error (no URBs submitted)
 */
static int starturbs(struct bc_state *bcs)
{
      struct bas_bc_state *ubc = bcs->hw.bas;
      struct urb *urb;
      int j, k;
      int rc;

      /* initialize L2 reception */
      if (bcs->proto2 == ISDN_PROTO_L2_HDLC)
            bcs->inputstate |= INS_flag_hunt;

      /* submit all isochronous input URBs */
      atomic_set(&ubc->running, 1);
      for (k = 0; k < BAS_INURBS; k++) {
            urb = ubc->isoinurbs[k];
            if (!urb) {
                  rc = -EFAULT;
                  goto error;
            }

            urb->dev = bcs->cs->hw.bas->udev;
            urb->pipe = usb_rcvisocpipe(urb->dev, 3 + 2 * bcs->channel);
            urb->transfer_flags = URB_ISO_ASAP;
            urb->transfer_buffer = ubc->isoinbuf + k * BAS_INBUFSIZE;
            urb->transfer_buffer_length = BAS_INBUFSIZE;
            urb->number_of_packets = BAS_NUMFRAMES;
            urb->interval = BAS_FRAMETIME;
            urb->complete = read_iso_callback;
            urb->context = bcs;
            for (j = 0; j < BAS_NUMFRAMES; j++) {
                  urb->iso_frame_desc[j].offset = j * BAS_MAXFRAME;
                  urb->iso_frame_desc[j].length = BAS_MAXFRAME;
                  urb->iso_frame_desc[j].status = 0;
                  urb->iso_frame_desc[j].actual_length = 0;
            }

            dump_urb(DEBUG_ISO, "Initial isoc read", urb);
            if ((rc = usb_submit_urb(urb, GFP_ATOMIC)) != 0)
                  goto error;
      }

      /* initialize L2 transmission */
      gigaset_isowbuf_init(ubc->isooutbuf, PPP_FLAG);

      /* set up isochronous output URBs for flag idling */
      for (k = 0; k < BAS_OUTURBS; ++k) {
            urb = ubc->isoouturbs[k].urb;
            if (!urb) {
                  rc = -EFAULT;
                  goto error;
            }
            urb->dev = bcs->cs->hw.bas->udev;
            urb->pipe = usb_sndisocpipe(urb->dev, 4 + 2 * bcs->channel);
            urb->transfer_flags = URB_ISO_ASAP;
            urb->transfer_buffer = ubc->isooutbuf->data;
            urb->transfer_buffer_length = sizeof(ubc->isooutbuf->data);
            urb->number_of_packets = BAS_NUMFRAMES;
            urb->interval = BAS_FRAMETIME;
            urb->complete = write_iso_callback;
            urb->context = &ubc->isoouturbs[k];
            for (j = 0; j < BAS_NUMFRAMES; ++j) {
                  urb->iso_frame_desc[j].offset = BAS_OUTBUFSIZE;
                  urb->iso_frame_desc[j].length = BAS_NORMFRAME;
                  urb->iso_frame_desc[j].status = 0;
                  urb->iso_frame_desc[j].actual_length = 0;
            }
            ubc->isoouturbs[k].limit = -1;
      }

      /* submit two URBs, keep third one */
      for (k = 0; k < 2; ++k) {
            dump_urb(DEBUG_ISO, "Initial isoc write", urb);
            rc = usb_submit_urb(ubc->isoouturbs[k].urb, GFP_ATOMIC);
            if (rc != 0)
                  goto error;
      }
      dump_urb(DEBUG_ISO, "Initial isoc write (free)", urb);
      ubc->isooutfree = &ubc->isoouturbs[2];
      ubc->isooutdone = ubc->isooutovfl = NULL;
      return 0;
 error:
      stopurbs(ubc);
      return rc;
}

/* stopurbs
 * cancel the USB request blocks for isochronous input and output
 * errors are silently ignored
 * argument:
 *    B channel control structure
 */
static void stopurbs(struct bas_bc_state *ubc)
{
      int k, rc;

      atomic_set(&ubc->running, 0);

      for (k = 0; k < BAS_INURBS; ++k) {
            rc = usb_unlink_urb(ubc->isoinurbs[k]);
            gig_dbg(DEBUG_ISO,
                  "%s: isoc input URB %d unlinked, result = %s",
                  __func__, k, get_usb_rcmsg(rc));
      }

      for (k = 0; k < BAS_OUTURBS; ++k) {
            rc = usb_unlink_urb(ubc->isoouturbs[k].urb);
            gig_dbg(DEBUG_ISO,
                  "%s: isoc output URB %d unlinked, result = %s",
                  __func__, k, get_usb_rcmsg(rc));
      }
}

/* Isochronous Write - Bottom Half */
/* =============================== */

/* submit_iso_write_urb
 * fill and submit the next isochronous write URB
 * parameters:
 *    ucx   context structure containing URB
 * return value:
 *    number of frames submitted in URB
 *    0 if URB not submitted because no data available (isooutbuf busy)
 *    error code < 0 on error
 */
static int submit_iso_write_urb(struct isow_urbctx_t *ucx)
{
      struct urb *urb = ucx->urb;
      struct bas_bc_state *ubc = ucx->bcs->hw.bas;
      struct usb_iso_packet_descriptor *ifd;
      int corrbytes, nframe, rc;

      /* urb->dev is clobbered by USB subsystem */
      urb->dev = ucx->bcs->cs->hw.bas->udev;
      urb->transfer_flags = URB_ISO_ASAP;
      urb->transfer_buffer = ubc->isooutbuf->data;
      urb->transfer_buffer_length = sizeof(ubc->isooutbuf->data);

      for (nframe = 0; nframe < BAS_NUMFRAMES; nframe++) {
            ifd = &urb->iso_frame_desc[nframe];

            /* compute frame length according to flow control */
            ifd->length = BAS_NORMFRAME;
            if ((corrbytes = atomic_read(&ubc->corrbytes)) != 0) {
                  gig_dbg(DEBUG_ISO, "%s: corrbytes=%d",
                        __func__, corrbytes);
                  if (corrbytes > BAS_HIGHFRAME - BAS_NORMFRAME)
                        corrbytes = BAS_HIGHFRAME - BAS_NORMFRAME;
                  else if (corrbytes < BAS_LOWFRAME - BAS_NORMFRAME)
                        corrbytes = BAS_LOWFRAME - BAS_NORMFRAME;
                  ifd->length += corrbytes;
                  atomic_add(-corrbytes, &ubc->corrbytes);
            }

            /* retrieve block of data to send */
            ifd->offset = gigaset_isowbuf_getbytes(ubc->isooutbuf,
                                           ifd->length);
            if (ifd->offset < 0) {
                  if (ifd->offset == -EBUSY) {
                        gig_dbg(DEBUG_ISO,
                              "%s: buffer busy at frame %d",
                              __func__, nframe);
                        /* tasklet will be restarted from
                           gigaset_send_skb() */
                  } else {
                        dev_err(ucx->bcs->cs->dev,
                              "%s: buffer error %d at frame %d\n",
                              __func__, ifd->offset, nframe);
                        return ifd->offset;
                  }
                  break;
            }
            ucx->limit = atomic_read(&ubc->isooutbuf->nextread);
            ifd->status = 0;
            ifd->actual_length = 0;
      }
      if (unlikely(nframe == 0))
            return 0;   /* no data to send */
      urb->number_of_packets = nframe;

      rc = usb_submit_urb(urb, GFP_ATOMIC);
      if (unlikely(rc)) {
            if (rc == -ENODEV)
                  /* device removed - give up silently */
                  gig_dbg(DEBUG_ISO, "%s: disconnected", __func__);
            else
                  dev_err(ucx->bcs->cs->dev,
                        "could not submit isochronous write URB: %s\n",
                        get_usb_rcmsg(rc));
            return rc;
      }
      ++ubc->numsub;
      return nframe;
}

/* write_iso_tasklet
 * tasklet scheduled when an isochronous output URB from the Gigaset device
 * has completed
 * parameter:
 *    data  B channel state structure
 */
static void write_iso_tasklet(unsigned long data)
{
      struct bc_state *bcs = (struct bc_state *) data;
      struct bas_bc_state *ubc = bcs->hw.bas;
      struct cardstate *cs = bcs->cs;
      struct isow_urbctx_t *done, *next, *ovfl;
      struct urb *urb;
      struct usb_iso_packet_descriptor *ifd;
      int offset;
      unsigned long flags;
      int i;
      struct sk_buff *skb;
      int len;
      int rc;

      /* loop while completed URBs arrive in time */
      for (;;) {
            if (unlikely(!(atomic_read(&ubc->running)))) {
                  gig_dbg(DEBUG_ISO, "%s: not running", __func__);
                  return;
            }

            /* retrieve completed URBs */
            spin_lock_irqsave(&ubc->isooutlock, flags);
            done = ubc->isooutdone;
            ubc->isooutdone = NULL;
            ovfl = ubc->isooutovfl;
            ubc->isooutovfl = NULL;
            spin_unlock_irqrestore(&ubc->isooutlock, flags);
            if (ovfl) {
                  dev_err(cs->dev, "isochronous write buffer underrun\n");
                  error_hangup(bcs);
                  break;
            }
            if (!done)
                  break;

            /* submit free URB if available */
            spin_lock_irqsave(&ubc->isooutlock, flags);
            next = ubc->isooutfree;
            ubc->isooutfree = NULL;
            spin_unlock_irqrestore(&ubc->isooutlock, flags);
            if (next) {
                  rc = submit_iso_write_urb(next);
                  if (unlikely(rc <= 0 && rc != -ENODEV)) {
                        /* could not submit URB, put it back */
                        spin_lock_irqsave(&ubc->isooutlock, flags);
                        if (ubc->isooutfree == NULL) {
                              ubc->isooutfree = next;
                              next = NULL;
                        }
                        spin_unlock_irqrestore(&ubc->isooutlock, flags);
                        if (next) {
                              /* couldn't put it back */
                              dev_err(cs->dev,
                                    "losing isochronous write URB\n");
                              error_hangup(bcs);
                        }
                  }
            }

            /* process completed URB */
            urb = done->urb;
            switch (urb->status) {
            case -EXDEV:                  /* partial completion */
                  gig_dbg(DEBUG_ISO, "%s: URB partially completed",
                        __func__);
                  /* fall through - what's the difference anyway? */
            case 0:                       /* normal completion */
                  /* inspect individual frames
                   * assumptions (for lack of documentation):
                   * - actual_length bytes of first frame in error are
                   *   successfully sent
                   * - all following frames are not sent at all
                   */
                  offset = done->limit;   /* default (no error) */
                  for (i = 0; i < BAS_NUMFRAMES; i++) {
                        ifd = &urb->iso_frame_desc[i];
                        if (ifd->status ||
                            ifd->actual_length != ifd->length) {
                              dev_warn(cs->dev,
                                   "isochronous write: frame %d: %s, "
                                   "only %d of %d bytes sent\n",
                                   i, get_usb_statmsg(ifd->status),
                                   ifd->actual_length, ifd->length);
                              offset = (ifd->offset +
                                      ifd->actual_length)
                                     % BAS_OUTBUFSIZE;
                              break;
                        }
                  }
#ifdef CONFIG_GIGASET_DEBUG
                  /* check assumption on remaining frames */
                  for (; i < BAS_NUMFRAMES; i++) {
                        ifd = &urb->iso_frame_desc[i];
                        if (ifd->status != -EINPROGRESS
                            || ifd->actual_length != 0) {
                              dev_warn(cs->dev,
                                   "isochronous write: frame %d: %s, "
                                   "%d of %d bytes sent\n",
                                   i, get_usb_statmsg(ifd->status),
                                   ifd->actual_length, ifd->length);
                              offset = (ifd->offset +
                                      ifd->actual_length)
                                     % BAS_OUTBUFSIZE;
                              break;
                        }
                  }
#endif
                  break;
            case -EPIPE:                  /* stall - probably underrun */
                  dev_err(cs->dev, "isochronous write stalled\n");
                  error_hangup(bcs);
                  break;
            default:                /* severe trouble */
                  dev_warn(cs->dev, "isochronous write: %s\n",
                         get_usb_statmsg(urb->status));
            }

            /* mark the write buffer area covered by this URB as free */
            if (done->limit >= 0)
                  atomic_set(&ubc->isooutbuf->read, done->limit);

            /* mark URB as free */
            spin_lock_irqsave(&ubc->isooutlock, flags);
            next = ubc->isooutfree;
            ubc->isooutfree = done;
            spin_unlock_irqrestore(&ubc->isooutlock, flags);
            if (next) {
                  /* only one URB still active - resubmit one */
                  rc = submit_iso_write_urb(next);
                  if (unlikely(rc <= 0 && rc != -ENODEV)) {
                        /* couldn't submit */
                        error_hangup(bcs);
                  }
            }
      }

      /* process queued SKBs */
      while ((skb = skb_dequeue(&bcs->squeue))) {
            /* copy to output buffer, doing L2 encapsulation */
            len = skb->len;
            if (gigaset_isoc_buildframe(bcs, skb->data, len) == -EAGAIN) {
                  /* insufficient buffer space, push back onto queue */
                  skb_queue_head(&bcs->squeue, skb);
                  gig_dbg(DEBUG_ISO, "%s: skb requeued, qlen=%d",
                        __func__, skb_queue_len(&bcs->squeue));
                  break;
            }
            skb_pull(skb, len);
            gigaset_skb_sent(bcs, skb);
            dev_kfree_skb_any(skb);
      }
}

/* Isochronous Read - Bottom Half */
/* ============================== */

/* read_iso_tasklet
 * tasklet scheduled when an isochronous input URB from the Gigaset device
 * has completed
 * parameter:
 *    data  B channel state structure
 */
static void read_iso_tasklet(unsigned long data)
{
      struct bc_state *bcs = (struct bc_state *) data;
      struct bas_bc_state *ubc = bcs->hw.bas;
      struct cardstate *cs = bcs->cs;
      struct urb *urb;
      char *rcvbuf;
      unsigned long flags;
      int totleft, numbytes, offset, frame, rc;

      /* loop while more completed URBs arrive in the meantime */
      for (;;) {
            /* retrieve URB */
            spin_lock_irqsave(&ubc->isoinlock, flags);
            if (!(urb = ubc->isoindone)) {
                  spin_unlock_irqrestore(&ubc->isoinlock, flags);
                  return;
            }
            ubc->isoindone = NULL;
            if (unlikely(ubc->loststatus != -EINPROGRESS)) {
                  dev_warn(cs->dev,
                         "isochronous read overrun, "
                         "dropped URB with status: %s, %d bytes lost\n",
                         get_usb_statmsg(ubc->loststatus),
                         ubc->isoinlost);
                  ubc->loststatus = -EINPROGRESS;
            }
            spin_unlock_irqrestore(&ubc->isoinlock, flags);

            if (unlikely(!(atomic_read(&ubc->running)))) {
                  gig_dbg(DEBUG_ISO,
                        "%s: channel not running, "
                        "dropped URB with status: %s",
                        __func__, get_usb_statmsg(urb->status));
                  return;
            }

            switch (urb->status) {
            case 0:                       /* normal completion */
                  break;
            case -EXDEV:                  /* inspect individual frames
                                       (we do that anyway) */
                  gig_dbg(DEBUG_ISO, "%s: URB partially completed",
                        __func__);
                  break;
            case -ENOENT:
            case -ECONNRESET:
            case -EINPROGRESS:
                  gig_dbg(DEBUG_ISO, "%s: %s",
                        __func__, get_usb_statmsg(urb->status));
                  continue;         /* -> skip */
            case -EPIPE:
                  dev_err(cs->dev, "isochronous read stalled\n");
                  error_hangup(bcs);
                  continue;         /* -> skip */
            default:                /* severe trouble */
                  dev_warn(cs->dev, "isochronous read: %s\n",
                         get_usb_statmsg(urb->status));
                  goto error;
            }

            rcvbuf = urb->transfer_buffer;
            totleft = urb->actual_length;
            for (frame = 0; totleft > 0 && frame < BAS_NUMFRAMES; frame++) {
                  if (unlikely(urb->iso_frame_desc[frame].status)) {
                        dev_warn(cs->dev,
                               "isochronous read: frame %d: %s\n",
                               frame,
                               get_usb_statmsg(
                                  urb->iso_frame_desc[frame].status));
                        break;
                  }
                  numbytes = urb->iso_frame_desc[frame].actual_length;
                  if (unlikely(numbytes > BAS_MAXFRAME)) {
                        dev_warn(cs->dev,
                               "isochronous read: frame %d: "
                               "numbytes (%d) > BAS_MAXFRAME\n",
                               frame, numbytes);
                        break;
                  }
                  if (unlikely(numbytes > totleft)) {
                        dev_warn(cs->dev,
                               "isochronous read: frame %d: "
                               "numbytes (%d) > totleft (%d)\n",
                               frame, numbytes, totleft);
                        break;
                  }
                  offset = urb->iso_frame_desc[frame].offset;
                  if (unlikely(offset + numbytes > BAS_INBUFSIZE)) {
                        dev_warn(cs->dev,
                               "isochronous read: frame %d: "
                               "offset (%d) + numbytes (%d) "
                               "> BAS_INBUFSIZE\n",
                               frame, offset, numbytes);
                        break;
                  }
                  gigaset_isoc_receive(rcvbuf + offset, numbytes, bcs);
                  totleft -= numbytes;
            }
            if (unlikely(totleft > 0))
                  dev_warn(cs->dev,
                         "isochronous read: %d data bytes missing\n",
                         totleft);

      error:
            /* URB processed, resubmit */
            for (frame = 0; frame < BAS_NUMFRAMES; frame++) {
                  urb->iso_frame_desc[frame].status = 0;
                  urb->iso_frame_desc[frame].actual_length = 0;
            }
            /* urb->dev is clobbered by USB subsystem */
            urb->dev = bcs->cs->hw.bas->udev;
            urb->transfer_flags = URB_ISO_ASAP;
            urb->number_of_packets = BAS_NUMFRAMES;
            rc = usb_submit_urb(urb, GFP_ATOMIC);
            if (unlikely(rc != 0 && rc != -ENODEV)) {
                  dev_err(cs->dev,
                        "could not resubmit isochronous read URB: %s\n",
                        get_usb_rcmsg(rc));
                  dump_urb(DEBUG_ISO, "resubmit iso read", urb);
                  error_hangup(bcs);
            }
      }
}

/* Channel Operations */
/* ================== */

/* req_timeout
 * timeout routine for control output request
 * argument:
 *    B channel control structure
 */
static void req_timeout(unsigned long data)
{
      struct bc_state *bcs = (struct bc_state *) data;
      struct bas_cardstate *ucs = bcs->cs->hw.bas;
      int pending;
      unsigned long flags;

      check_pending(ucs);

      spin_lock_irqsave(&ucs->lock, flags);
      pending = ucs->pending;
      ucs->pending = 0;
      spin_unlock_irqrestore(&ucs->lock, flags);

      switch (pending) {
      case 0:                             /* no pending request */
            gig_dbg(DEBUG_USBREQ, "%s: no request pending", __func__);
            break;

      case HD_OPEN_ATCHANNEL:
            dev_err(bcs->cs->dev, "timeout opening AT channel\n");
            error_reset(bcs->cs);
            break;

      case HD_OPEN_B2CHANNEL:
      case HD_OPEN_B1CHANNEL:
            dev_err(bcs->cs->dev, "timeout opening channel %d\n",
                  bcs->channel + 1);
            error_hangup(bcs);
            break;

      case HD_CLOSE_ATCHANNEL:
            dev_err(bcs->cs->dev, "timeout closing AT channel\n");
            break;

      case HD_CLOSE_B2CHANNEL:
      case HD_CLOSE_B1CHANNEL:
            dev_err(bcs->cs->dev, "timeout closing channel %d\n",
                  bcs->channel + 1);
            error_reset(bcs->cs);
            break;

      default:
            dev_warn(bcs->cs->dev, "request 0x%02x timed out, clearing\n",
                   pending);
      }
}

/* write_ctrl_callback
 * USB completion handler for control pipe output
 * called by the USB subsystem in interrupt context
 * parameter:
 *    urb   USB request block of completed request
 *          urb->context = hardware specific controller state structure
 */
static void write_ctrl_callback(struct urb *urb)
{
      struct bas_cardstate *ucs = urb->context;
      int rc;
      unsigned long flags;

      /* check status */
      switch (urb->status) {
      case 0:                             /* normal completion */
            spin_lock_irqsave(&ucs->lock, flags);
            switch (ucs->pending) {
            case HD_DEVICE_INIT_ACK:      /* no reply expected */
                  del_timer(&ucs->timer_ctrl);
                  ucs->pending = 0;
                  break;
            }
            spin_unlock_irqrestore(&ucs->lock, flags);
            return;

      case -ENOENT:                 /* cancelled */
      case -ECONNRESET:       /* cancelled (async) */
      case -EINPROGRESS:            /* pending */
      case -ENODEV:                 /* device removed */
      case -ESHUTDOWN:        /* device shut down */
            /* ignore silently */
            gig_dbg(DEBUG_USBREQ, "%s: %s",
                  __func__, get_usb_statmsg(urb->status));
            break;

      default:                      /* any failure */
            if (++ucs->retry_ctrl > BAS_RETRY) {
                  dev_err(&ucs->interface->dev,
                        "control request 0x%02x failed: %s\n",
                        ucs->dr_ctrl.bRequest,
                        get_usb_statmsg(urb->status));
                  break;            /* give up */
            }
            dev_notice(&ucs->interface->dev,
                     "control request 0x%02x: %s, retry %d\n",
                     ucs->dr_ctrl.bRequest, get_usb_statmsg(urb->status),
                     ucs->retry_ctrl);
            /* urb->dev is clobbered by USB subsystem */
            urb->dev = ucs->udev;
            rc = usb_submit_urb(urb, GFP_ATOMIC);
            if (unlikely(rc)) {
                  dev_err(&ucs->interface->dev,
                        "could not resubmit request 0x%02x: %s\n",
                        ucs->dr_ctrl.bRequest, get_usb_rcmsg(rc));
                  break;
            }
            /* resubmitted */
            return;
      }

      /* failed, clear pending request */
      spin_lock_irqsave(&ucs->lock, flags);
      del_timer(&ucs->timer_ctrl);
      ucs->pending = 0;
      spin_unlock_irqrestore(&ucs->lock, flags);
}

/* req_submit
 * submit a control output request without message buffer to the Gigaset base
 * and optionally start a timeout
 * parameters:
 *    bcs   B channel control structure
 *    req   control request code (HD_*)
 *    val   control request parameter value (set to 0 if unused)
 *    timeout     timeout in seconds (0: no timeout)
 * return value:
 *    0 on success
 *    -EBUSY if another request is pending
 *    any URB submission error code
 */
static int req_submit(struct bc_state *bcs, int req, int val, int timeout)
{
      struct bas_cardstate *ucs = bcs->cs->hw.bas;
      int ret;
      unsigned long flags;

      gig_dbg(DEBUG_USBREQ, "-------> 0x%02x (%d)", req, val);

      spin_lock_irqsave(&ucs->lock, flags);
      if (ucs->pending) {
            spin_unlock_irqrestore(&ucs->lock, flags);
            dev_err(bcs->cs->dev,
                  "submission of request 0x%02x failed: "
                  "request 0x%02x still pending\n",
                  req, ucs->pending);
            return -EBUSY;
      }

      ucs->dr_ctrl.bRequestType = OUT_VENDOR_REQ;
      ucs->dr_ctrl.bRequest = req;
      ucs->dr_ctrl.wValue = cpu_to_le16(val);
      ucs->dr_ctrl.wIndex = 0;
      ucs->dr_ctrl.wLength = 0;
      usb_fill_control_urb(ucs->urb_ctrl, ucs->udev,
                       usb_sndctrlpipe(ucs->udev, 0),
                       (unsigned char*) &ucs->dr_ctrl, NULL, 0,
                       write_ctrl_callback, ucs);
      ucs->retry_ctrl = 0;
      ret = usb_submit_urb(ucs->urb_ctrl, GFP_ATOMIC);
      if (unlikely(ret)) {
            dev_err(bcs->cs->dev, "could not submit request 0x%02x: %s\n",
                  req, get_usb_rcmsg(ret));
            spin_unlock_irqrestore(&ucs->lock, flags);
            return ret;
      }
      ucs->pending = req;

      if (timeout > 0) {
            gig_dbg(DEBUG_USBREQ, "setting timeout of %d/10 secs", timeout);
            ucs->timer_ctrl.expires = jiffies + timeout * HZ / 10;
            ucs->timer_ctrl.data = (unsigned long) bcs;
            ucs->timer_ctrl.function = req_timeout;
            add_timer(&ucs->timer_ctrl);
      }

      spin_unlock_irqrestore(&ucs->lock, flags);
      return 0;
}

/* gigaset_init_bchannel
 * called by common.c to connect a B channel
 * initialize isochronous I/O and tell the Gigaset base to open the channel
 * argument:
 *    B channel control structure
 * return value:
 *    0 on success, error code < 0 on error
 */
static int gigaset_init_bchannel(struct bc_state *bcs)
{
      int req, ret;
      unsigned long flags;

      spin_lock_irqsave(&bcs->cs->lock, flags);
      if (unlikely(!bcs->cs->connected)) {
            gig_dbg(DEBUG_USBREQ, "%s: not connected", __func__);
            spin_unlock_irqrestore(&bcs->cs->lock, flags);
            return -ENODEV;
      }

      if ((ret = starturbs(bcs)) < 0) {
            dev_err(bcs->cs->dev,
                  "could not start isochronous I/O for channel B%d: %s\n",
                  bcs->channel + 1,
                  ret == -EFAULT ? "null URB" : get_usb_rcmsg(ret));
            if (ret != -ENODEV)
                  error_hangup(bcs);
            spin_unlock_irqrestore(&bcs->cs->lock, flags);
            return ret;
      }

      req = bcs->channel ? HD_OPEN_B2CHANNEL : HD_OPEN_B1CHANNEL;
      if ((ret = req_submit(bcs, req, 0, BAS_TIMEOUT)) < 0) {
            dev_err(bcs->cs->dev, "could not open channel B%d\n",
                  bcs->channel + 1);
            stopurbs(bcs->hw.bas);
            if (ret != -ENODEV)
                  error_hangup(bcs);
      }

      spin_unlock_irqrestore(&bcs->cs->lock, flags);
      return ret;
}

/* gigaset_close_bchannel
 * called by common.c to disconnect a B channel
 * tell the Gigaset base to close the channel
 * stopping isochronous I/O and LL notification will be done when the
 * acknowledgement for the close arrives
 * argument:
 *    B channel control structure
 * return value:
 *    0 on success, error code < 0 on error
 */
static int gigaset_close_bchannel(struct bc_state *bcs)
{
      int req, ret;
      unsigned long flags;

      spin_lock_irqsave(&bcs->cs->lock, flags);
      if (unlikely(!bcs->cs->connected)) {
            spin_unlock_irqrestore(&bcs->cs->lock, flags);
            gig_dbg(DEBUG_USBREQ, "%s: not connected", __func__);
            return -ENODEV;
      }

      if (!(atomic_read(&bcs->cs->hw.bas->basstate) &
            (bcs->channel ? BS_B2OPEN : BS_B1OPEN))) {
            /* channel not running: just signal common.c */
            spin_unlock_irqrestore(&bcs->cs->lock, flags);
            gigaset_bchannel_down(bcs);
            return 0;
      }

      /* channel running: tell device to close it */
      req = bcs->channel ? HD_CLOSE_B2CHANNEL : HD_CLOSE_B1CHANNEL;
      if ((ret = req_submit(bcs, req, 0, BAS_TIMEOUT)) < 0)
            dev_err(bcs->cs->dev, "closing channel B%d failed\n",
                  bcs->channel + 1);

      spin_unlock_irqrestore(&bcs->cs->lock, flags);
      return ret;
}

/* Device Operations */
/* ================= */

/* complete_cb
 * unqueue first command buffer from queue, waking any sleepers
 * must be called with cs->cmdlock held
 * parameter:
 *    cs    controller state structure
 */
static void complete_cb(struct cardstate *cs)
{
      struct cmdbuf_t *cb = cs->cmdbuf;

      /* unqueue completed buffer */
      cs->cmdbytes -= cs->curlen;
      gig_dbg(DEBUG_TRANSCMD|DEBUG_LOCKCMD,
            "write_command: sent %u bytes, %u left",
            cs->curlen, cs->cmdbytes);
      if ((cs->cmdbuf = cb->next) != NULL) {
            cs->cmdbuf->prev = NULL;
            cs->curlen = cs->cmdbuf->len;
      } else {
            cs->lastcmdbuf = NULL;
            cs->curlen = 0;
      }

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

      kfree(cb);
}

/* write_command_callback
 * USB completion handler for AT command transmission
 * called by the USB subsystem in interrupt context
 * parameter:
 *    urb   USB request block of completed request
 *          urb->context = controller state structure
 */
static void write_command_callback(struct urb *urb)
{
      struct cardstate *cs = urb->context;
      struct bas_cardstate *ucs = cs->hw.bas;
      unsigned long flags;

      update_basstate(ucs, 0, BS_ATWRPEND);

      /* check status */
      switch (urb->status) {
      case 0:                             /* normal completion */
            break;
      case -ENOENT:                 /* cancelled */
      case -ECONNRESET:       /* cancelled (async) */
      case -EINPROGRESS:            /* pending */
      case -ENODEV:                 /* device removed */
      case -ESHUTDOWN:        /* device shut down */
            /* ignore silently */
            gig_dbg(DEBUG_USBREQ, "%s: %s",
                  __func__, get_usb_statmsg(urb->status));
            return;
      default:                      /* any failure */
            if (++ucs->retry_cmd_out > BAS_RETRY) {
                  dev_warn(cs->dev,
                         "command write: %s, "
                         "giving up after %d retries\n",
                         get_usb_statmsg(urb->status),
                         ucs->retry_cmd_out);
                  break;
            }
            if (cs->cmdbuf == NULL) {
                  dev_warn(cs->dev,
                         "command write: %s, "
                         "cannot retry - cmdbuf gone\n",
                         get_usb_statmsg(urb->status));
                  break;
            }
            dev_notice(cs->dev, "command write: %s, retry %d\n",
                     get_usb_statmsg(urb->status), ucs->retry_cmd_out);
            if (atwrite_submit(cs, cs->cmdbuf->buf, cs->cmdbuf->len) >= 0)
                  /* resubmitted - bypass regular exit block */
                  return;
            /* command send failed, assume base still waiting */
            update_basstate(ucs, BS_ATREADY, 0);
      }

      spin_lock_irqsave(&cs->cmdlock, flags);
      if (cs->cmdbuf != NULL)
            complete_cb(cs);
      spin_unlock_irqrestore(&cs->cmdlock, flags);
}

/* atrdy_timeout
 * timeout routine for AT command transmission
 * argument:
 *    controller state structure
 */
static void atrdy_timeout(unsigned long data)
{
      struct cardstate *cs = (struct cardstate *) data;
      struct bas_cardstate *ucs = cs->hw.bas;

      dev_warn(cs->dev, "timeout waiting for HD_READY_SEND_ATDATA\n");

      /* fake the missing signal - what else can I do? */
      update_basstate(ucs, BS_ATREADY, BS_ATTIMER);
      start_cbsend(cs);
}

/* atwrite_submit
 * submit an HD_WRITE_ATMESSAGE command URB
 * parameters:
 *    cs    controller state structure
 *    buf   buffer containing command to send
 *    len   length of command to send
 * return value:
 *    0 on success
 *    -EBUSY if another request is pending
 *    any URB submission error code
 */
static int atwrite_submit(struct cardstate *cs, unsigned char *buf, int len)
{
      struct bas_cardstate *ucs = cs->hw.bas;
      int rc;

      gig_dbg(DEBUG_USBREQ, "-------> HD_WRITE_ATMESSAGE (%d)", len);

      if (update_basstate(ucs, BS_ATWRPEND, 0) & BS_ATWRPEND) {
            dev_err(cs->dev,
                  "could not submit HD_WRITE_ATMESSAGE: URB busy\n");
            return -EBUSY;
      }

      ucs->dr_cmd_out.bRequestType = OUT_VENDOR_REQ;
      ucs->dr_cmd_out.bRequest = HD_WRITE_ATMESSAGE;
      ucs->dr_cmd_out.wValue = 0;
      ucs->dr_cmd_out.wIndex = 0;
      ucs->dr_cmd_out.wLength = cpu_to_le16(len);
      usb_fill_control_urb(ucs->urb_cmd_out, ucs->udev,
                       usb_sndctrlpipe(ucs->udev, 0),
                       (unsigned char*) &ucs->dr_cmd_out, buf, len,
                       write_command_callback, cs);
      rc = usb_submit_urb(ucs->urb_cmd_out, GFP_ATOMIC);
      if (unlikely(rc)) {
            update_basstate(ucs, 0, BS_ATWRPEND);
            dev_err(cs->dev, "could not submit HD_WRITE_ATMESSAGE: %s\n",
                  get_usb_rcmsg(rc));
            return rc;
      }

      /* submitted successfully, start timeout if necessary */
      if (!(update_basstate(ucs, BS_ATTIMER, BS_ATREADY) & BS_ATTIMER)) {
            gig_dbg(DEBUG_OUTPUT, "setting ATREADY timeout of %d/10 secs",
                  ATRDY_TIMEOUT);
            ucs->timer_atrdy.expires = jiffies + ATRDY_TIMEOUT * HZ / 10;
            ucs->timer_atrdy.data = (unsigned long) cs;
            ucs->timer_atrdy.function = atrdy_timeout;
            add_timer(&ucs->timer_atrdy);
      }
      return 0;
}

/* start_cbsend
 * start transmission of AT command queue if necessary
 * parameter:
 *    cs          controller state structure
 * return value:
 *    0 on success
 *    error code < 0 on error
 */
static int start_cbsend(struct cardstate *cs)
{
      struct cmdbuf_t *cb;
      struct bas_cardstate *ucs = cs->hw.bas;
      unsigned long flags;
      int rc;
      int retval = 0;

      /* check if AT channel is open */
      if (!(atomic_read(&ucs->basstate) & BS_ATOPEN)) {
            gig_dbg(DEBUG_TRANSCMD|DEBUG_LOCKCMD, "AT channel not open");
            rc = req_submit(cs->bcs, HD_OPEN_ATCHANNEL, 0, BAS_TIMEOUT);
            if (rc < 0) {
                  /* flush command queue */
                  spin_lock_irqsave(&cs->cmdlock, flags);
                  while (cs->cmdbuf != NULL)
                        complete_cb(cs);
                  spin_unlock_irqrestore(&cs->cmdlock, flags);
            }
            return rc;
      }

      /* try to send first command in queue */
      spin_lock_irqsave(&cs->cmdlock, flags);

      while ((cb = cs->cmdbuf) != NULL &&
             atomic_read(&ucs->basstate) & BS_ATREADY) {
            ucs->retry_cmd_out = 0;
            rc = atwrite_submit(cs, cb->buf, cb->len);
            if (unlikely(rc)) {
                  retval = rc;
                  complete_cb(cs);
            }
      }

      spin_unlock_irqrestore(&cs->cmdlock, flags);
      return retval;
}

/* gigaset_write_cmd
 * This function is called by the device independent part of the driver
 * to transmit an AT command string to the Gigaset device.
 * It encapsulates the device specific method for transmission over the
 * direct USB connection to the base.
 * The command string is added to the queue of commands to send, and
 * USB transmission is started if necessary.
 * parameters:
 *    cs          controller state structure
 *    buf         command string to send
 *    len         number of bytes to send (max. IF_WRITEBUF)
 *    wake_tasklet      tasklet to run when transmission is completed
 *                (NULL if none)
 * return value:
 *    number of bytes queued on success
 *    error code < 0 on error
 */
static int gigaset_write_cmd(struct cardstate *cs,
                       const unsigned char *buf, int len,
                       struct tasklet_struct *wake_tasklet)
{
      struct cmdbuf_t *cb;
      unsigned long flags;
      int rc;

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

      if (len <= 0) {
            /* nothing to do */
            rc = 0;
            goto notqueued;
      }

      if (len > IF_WRITEBUF)
            len = IF_WRITEBUF;
      if (!(cb = kmalloc(sizeof(struct cmdbuf_t) + len, GFP_ATOMIC))) {
            dev_err(cs->dev, "%s: out of memory\n", __func__);
            rc = -ENOMEM;
            goto notqueued;
      }

      memcpy(cb->buf, buf, len);
      cb->len = len;
      cb->offset = 0;
      cb->next = NULL;
      cb->wake_tasklet = wake_tasklet;

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

      spin_lock_irqsave(&cs->lock, flags);
      if (unlikely(!cs->connected)) {
            spin_unlock_irqrestore(&cs->lock, flags);
            gig_dbg(DEBUG_USBREQ, "%s: not connected", __func__);
            /* flush command queue */
            spin_lock_irqsave(&cs->cmdlock, flags);
            while (cs->cmdbuf != NULL)
                  complete_cb(cs);
            spin_unlock_irqrestore(&cs->cmdlock, flags);
            return -ENODEV;
      }
      rc = start_cbsend(cs);
      spin_unlock_irqrestore(&cs->lock, flags);
      return rc < 0 ? rc : len;

notqueued:              /* request handled without queuing */
      if (wake_tasklet)
            tasklet_schedule(wake_tasklet);
      return rc;
}

/* gigaset_write_room
 * tty_driver.write_room interface routine
 * return number of characters the driver will accept to be written via
 * gigaset_write_cmd
 * parameter:
 *    controller state structure
 * return value:
 *    number of characters
 */
static int gigaset_write_room(struct cardstate *cs)
{
      return IF_WRITEBUF;
}

/* gigaset_chars_in_buffer
 * tty_driver.chars_in_buffer interface routine
 * return number of characters waiting to be sent
 * parameter:
 *    controller state structure
 * return value:
 *    number of characters
 */
static int gigaset_chars_in_buffer(struct cardstate *cs)
{
      return cs->cmdbytes;
}

/* gigaset_brkchars
 * implementation of ioctl(GIGASET_BRKCHARS)
 * parameter:
 *    controller state structure
 * return value:
 *    -EINVAL (unimplemented function)
 */
static int gigaset_brkchars(struct cardstate *cs, const unsigned char buf[6])
{
      return -EINVAL;
}


/* Device Initialization/Shutdown */
/* ============================== */

/* Free hardware dependent part of the B channel structure
 * parameter:
 *    bcs   B channel structure
 * return value:
 *    !=0 on success
 */
static int gigaset_freebcshw(struct bc_state *bcs)
{
      struct bas_bc_state *ubc = bcs->hw.bas;
      int i;

      if (!ubc)
            return 0;

      /* kill URBs and tasklets before freeing - better safe than sorry */
      atomic_set(&ubc->running, 0);
      gig_dbg(DEBUG_INIT, "%s: killing iso URBs", __func__);
      for (i = 0; i < BAS_OUTURBS; ++i) {
            usb_kill_urb(ubc->isoouturbs[i].urb);
            usb_free_urb(ubc->isoouturbs[i].urb);
      }
      for (i = 0; i < BAS_INURBS; ++i) {
            usb_kill_urb(ubc->isoinurbs[i]);
            usb_free_urb(ubc->isoinurbs[i]);
      }
      tasklet_kill(&ubc->sent_tasklet);
      tasklet_kill(&ubc->rcvd_tasklet);
      kfree(ubc->isooutbuf);
      kfree(ubc);
      bcs->hw.bas = NULL;
      return 1;
}

/* Initialize hardware dependent part of the B channel structure
 * parameter:
 *    bcs   B channel structure
 * return value:
 *    !=0 on success
 */
static int gigaset_initbcshw(struct bc_state *bcs)
{
      int i;
      struct bas_bc_state *ubc;

      bcs->hw.bas = ubc = kmalloc(sizeof(struct bas_bc_state), GFP_KERNEL);
      if (!ubc) {
            err("could not allocate bas_bc_state");
            return 0;
      }

      atomic_set(&ubc->running, 0);
      atomic_set(&ubc->corrbytes, 0);
      spin_lock_init(&ubc->isooutlock);
      for (i = 0; i < BAS_OUTURBS; ++i) {
            ubc->isoouturbs[i].urb = NULL;
            ubc->isoouturbs[i].bcs = bcs;
      }
      ubc->isooutdone = ubc->isooutfree = ubc->isooutovfl = NULL;
      ubc->numsub = 0;
      if (!(ubc->isooutbuf = kmalloc(sizeof(struct isowbuf_t), GFP_KERNEL))) {
            err("could not allocate isochronous output buffer");
            kfree(ubc);
            bcs->hw.bas = NULL;
            return 0;
      }
      tasklet_init(&ubc->sent_tasklet,
                 &write_iso_tasklet, (unsigned long) bcs);

      spin_lock_init(&ubc->isoinlock);
      for (i = 0; i < BAS_INURBS; ++i)
            ubc->isoinurbs[i] = NULL;
      ubc->isoindone = NULL;
      ubc->loststatus = -EINPROGRESS;
      ubc->isoinlost = 0;
      ubc->seqlen = 0;
      ubc->inbyte = 0;
      ubc->inbits = 0;
      ubc->goodbytes = 0;
      ubc->alignerrs = 0;
      ubc->fcserrs = 0;
      ubc->frameerrs = 0;
      ubc->giants = 0;
      ubc->runts = 0;
      ubc->aborts = 0;
      ubc->shared0s = 0;
      ubc->stolen0s = 0;
      tasklet_init(&ubc->rcvd_tasklet,
                 &read_iso_tasklet, (unsigned long) bcs);
      return 1;
}

static void gigaset_reinitbcshw(struct bc_state *bcs)
{
      struct bas_bc_state *ubc = bcs->hw.bas;

      atomic_set(&bcs->hw.bas->running, 0);
      atomic_set(&bcs->hw.bas->corrbytes, 0);
      bcs->hw.bas->numsub = 0;
      spin_lock_init(&ubc->isooutlock);
      spin_lock_init(&ubc->isoinlock);
      ubc->loststatus = -EINPROGRESS;
}

static void gigaset_freecshw(struct cardstate *cs)
{
      /* timers, URBs and rcvbuf are disposed of in disconnect */
      kfree(cs->hw.bas);
      cs->hw.bas = NULL;
}

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

      cs->hw.bas = ucs = kmalloc(sizeof *ucs, GFP_KERNEL);
      if (!ucs)
            return 0;

      ucs->urb_cmd_in = NULL;
      ucs->urb_cmd_out = NULL;
      ucs->rcvbuf = NULL;
      ucs->rcvbuf_size = 0;

      spin_lock_init(&ucs->lock);
      ucs->pending = 0;

      atomic_set(&ucs->basstate, 0);
      init_timer(&ucs->timer_ctrl);
      init_timer(&ucs->timer_atrdy);
      init_timer(&ucs->timer_cmd_in);

      return 1;
}

/* freeurbs
 * unlink and deallocate all URBs unconditionally
 * caller must make sure that no commands are still in progress
 * parameter:
 *    cs    controller state structure
 */
static void freeurbs(struct cardstate *cs)
{
      struct bas_cardstate *ucs = cs->hw.bas;
      struct bas_bc_state *ubc;
      int i, j;

      gig_dbg(DEBUG_INIT, "%s: killing URBs", __func__);
      for (j = 0; j < 2; ++j) {
            ubc = cs->bcs[j].hw.bas;
            for (i = 0; i < BAS_OUTURBS; ++i) {
                  usb_kill_urb(ubc->isoouturbs[i].urb);
                  usb_free_urb(ubc->isoouturbs[i].urb);
                  ubc->isoouturbs[i].urb = NULL;
            }
            for (i = 0; i < BAS_INURBS; ++i) {
                  usb_kill_urb(ubc->isoinurbs[i]);
                  usb_free_urb(ubc->isoinurbs[i]);
                  ubc->isoinurbs[i] = NULL;
            }
      }
      usb_kill_urb(ucs->urb_int_in);
      usb_free_urb(ucs->urb_int_in);
      ucs->urb_int_in = NULL;
      usb_kill_urb(ucs->urb_cmd_out);
      usb_free_urb(ucs->urb_cmd_out);
      ucs->urb_cmd_out = NULL;
      usb_kill_urb(ucs->urb_cmd_in);
      usb_free_urb(ucs->urb_cmd_in);
      ucs->urb_cmd_in = NULL;
      usb_kill_urb(ucs->urb_ctrl);
      usb_free_urb(ucs->urb_ctrl);
      ucs->urb_ctrl = NULL;
}

/* gigaset_probe
 * This function is called when a new USB device is connected.
 * It checks whether the new device is handled by this driver.
 */
static int gigaset_probe(struct usb_interface *interface,
                   const struct usb_device_id *id)
{
      struct usb_host_interface *hostif;
      struct usb_device *udev = interface_to_usbdev(interface);
      struct cardstate *cs = NULL;
      struct bas_cardstate *ucs = NULL;
      struct bas_bc_state *ubc;
      struct usb_endpoint_descriptor *endpoint;
      int i, j;
      int rc;

      gig_dbg(DEBUG_ANY,
            "%s: Check if device matches .. (Vendor: 0x%x, Product: 0x%x)",
            __func__, le16_to_cpu(udev->descriptor.idVendor),
            le16_to_cpu(udev->descriptor.idProduct));

      /* set required alternate setting */
      hostif = interface->cur_altsetting;
      if (hostif->desc.bAlternateSetting != 3) {
            gig_dbg(DEBUG_ANY,
                  "%s: wrong alternate setting %d - trying to switch",
                  __func__, hostif->desc.bAlternateSetting);
            if (usb_set_interface(udev, hostif->desc.bInterfaceNumber, 3) < 0) {
                  dev_warn(&udev->dev, "usb_set_interface failed, "
                         "device %d interface %d altsetting %d\n",
                         udev->devnum, hostif->desc.bInterfaceNumber,
                         hostif->desc.bAlternateSetting);
                  return -ENODEV;
            }
            hostif = interface->cur_altsetting;
      }

      /* Reject application specific interfaces
       */
      if (hostif->desc.bInterfaceClass != 255) {
            dev_warn(&udev->dev, "%s: bInterfaceClass == %d\n",
                   __func__, hostif->desc.bInterfaceClass);
            return -ENODEV;
      }

      dev_info(&udev->dev,
             "%s: Device matched (Vendor: 0x%x, Product: 0x%x)\n",
             __func__, le16_to_cpu(udev->descriptor.idVendor),
             le16_to_cpu(udev->descriptor.idProduct));

      cs = gigaset_getunassignedcs(driver);
      if (!cs) {
            dev_err(&udev->dev, "no free cardstate\n");
            return -ENODEV;
      }
      ucs = cs->hw.bas;

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

      /* allocate URBs:
       * - one for the interrupt pipe
       * - three for the different uses of the default control pipe
       * - three for each isochronous pipe
       */
      if (!(ucs->urb_int_in = usb_alloc_urb(0, GFP_KERNEL)) ||
          !(ucs->urb_cmd_in = usb_alloc_urb(0, GFP_KERNEL)) ||
          !(ucs->urb_cmd_out = usb_alloc_urb(0, GFP_KERNEL)) ||
          !(ucs->urb_ctrl = usb_alloc_urb(0, GFP_KERNEL)))
            goto allocerr;

      for (j = 0; j < 2; ++j) {
            ubc = cs->bcs[j].hw.bas;
            for (i = 0; i < BAS_OUTURBS; ++i)
                  if (!(ubc->isoouturbs[i].urb =
                        usb_alloc_urb(BAS_NUMFRAMES, GFP_KERNEL)))
                        goto allocerr;
            for (i = 0; i < BAS_INURBS; ++i)
                  if (!(ubc->isoinurbs[i] =
                        usb_alloc_urb(BAS_NUMFRAMES, GFP_KERNEL)))
                        goto allocerr;
      }

      ucs->rcvbuf = NULL;
      ucs->rcvbuf_size = 0;

      /* Fill the interrupt urb and send it to the core */
      endpoint = &hostif->endpoint[0].desc;
      usb_fill_int_urb(ucs->urb_int_in, udev,
                   usb_rcvintpipe(udev,
                              (endpoint->bEndpointAddress) & 0x0f),
                   ucs->int_in_buf, 3, read_int_callback, cs,
                   endpoint->bInterval);
      if ((rc = usb_submit_urb(ucs->urb_int_in, GFP_KERNEL)) != 0) {
            dev_err(cs->dev, "could not submit interrupt URB: %s\n",
                  get_usb_rcmsg(rc));
            goto error;
      }

      /* tell the device that the driver is ready */
      if ((rc = req_submit(cs->bcs, HD_DEVICE_INIT_ACK, 0, 0)) != 0)
            goto error;

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

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

      if (!gigaset_start(cs))
            goto error;

      return 0;

allocerr:
      dev_err(cs->dev, "could not allocate URBs\n");
error:
      freeurbs(cs);
      usb_set_intfdata(interface, NULL);
      gigaset_unassign(cs);
      return -ENODEV;
}

/* gigaset_disconnect
 * This function is called when the Gigaset base is unplugged.
 */
static void gigaset_disconnect(struct usb_interface *interface)
{
      struct cardstate *cs;
      struct bas_cardstate *ucs;
      int j;

      cs = usb_get_intfdata(interface);

      ucs = cs->hw.bas;

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

      /* mark base as not ready, all channels disconnected */
      atomic_set(&ucs->basstate, 0);

      /* tell LL all channels are down */
      //FIXME shouldn't gigaset_stop() do this?
      for (j = 0; j < 2; ++j)
            gigaset_bchannel_down(cs->bcs + j);

      /* stop driver (common part) */
      gigaset_stop(cs);

      /* stop timers and URBs, free ressources */
      del_timer_sync(&ucs->timer_ctrl);
      del_timer_sync(&ucs->timer_atrdy);
      del_timer_sync(&ucs->timer_cmd_in);
      freeurbs(cs);
      usb_set_intfdata(interface, NULL);
      kfree(ucs->rcvbuf);
      ucs->rcvbuf = NULL;
      ucs->rcvbuf_size = 0;
      usb_put_dev(ucs->udev);
      ucs->interface = NULL;
      ucs->udev = NULL;
      cs->dev = NULL;
      gigaset_unassign(cs);
}

static const struct gigaset_ops gigops = {
      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_isoc_send_skb,
      gigaset_isoc_input,
};

/* bas_gigaset_init
 * This function is called after the kernel module is loaded.
 */
static int __init bas_gigaset_init(void)
{
      int result;

      /* allocate memory for our driver state and intialize it */
      if ((driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
                               GIGASET_MODULENAME, GIGASET_DEVNAME,
                               &gigops, THIS_MODULE)) == NULL)
            goto error;

      /* allocate memory for our device state and intialize it */
      cardstate = gigaset_initcs(driver, 2, 0, 0, cidmode,
                           GIGASET_MODULENAME);
      if (!cardstate)
            goto error;

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

      info(DRIVER_AUTHOR);
      info(DRIVER_DESC);
      return 0;

error:      if (cardstate)
            gigaset_freecs(cardstate);
      cardstate = NULL;
      if (driver)
            gigaset_freedriver(driver);
      driver = NULL;
      return -1;
}

/* bas_gigaset_exit
 * This function is called before the kernel module is unloaded.
 */
static void __exit bas_gigaset_exit(void)
{
      struct bas_cardstate *ucs = cardstate->hw.bas;

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

      gigaset_shutdown(cardstate);
      /* from now on, no isdn callback should be possible */

      /* close all still open channels */
      if (atomic_read(&ucs->basstate) & BS_B1OPEN) {
            gig_dbg(DEBUG_INIT, "closing B1 channel");
            usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
                        HD_CLOSE_B1CHANNEL, OUT_VENDOR_REQ, 0, 0,
                        NULL, 0, BAS_TIMEOUT);
      }
      if (atomic_read(&ucs->basstate) & BS_B2OPEN) {
            gig_dbg(DEBUG_INIT, "closing B2 channel");
            usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
                        HD_CLOSE_B2CHANNEL, OUT_VENDOR_REQ, 0, 0,
                        NULL, 0, BAS_TIMEOUT);
      }
      if (atomic_read(&ucs->basstate) & BS_ATOPEN) {
            gig_dbg(DEBUG_INIT, "closing AT channel");
            usb_control_msg(ucs->udev, usb_sndctrlpipe(ucs->udev, 0),
                        HD_CLOSE_ATCHANNEL, OUT_VENDOR_REQ, 0, 0,
                        NULL, 0, BAS_TIMEOUT);
      }
      atomic_set(&ucs->basstate, 0);

      /* 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_freecs(cardstate);
      cardstate = NULL;
      gigaset_freedriver(driver);
      driver = NULL;
}


module_init(bas_gigaset_init);
module_exit(bas_gigaset_exit);

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

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