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/*****************************************************************************
* sdla_chdlc.c    WANPIPE(tm) Multiprotocol WAN Link Driver. Cisco HDLC module.
*
* Authors:     Nenad Corbic <ncorbic@sangoma.com>
*        Gideon Hack  
*
* Copyright:    (c) 1995-2001 Sangoma Technologies Inc.
*
*        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.
* ============================================================================
* Feb 28, 2001  Nenad Corbic    Updated if_tx_timeout() routine for 
*                 2.4.X kernels.
* Jan 25, 2001  Nenad Corbic    Added a TTY Sync serial driver over the
*                 HDLC streaming protocol
*                 Added a TTY Async serial driver over the
*                 Async protocol.
* Dec 15, 2000  Nenad Corbic    Updated for 2.4.X Kernel support
* Nov 13, 2000  Nenad Corbic    Added true interface type encoding option.
*                 Tcpdump doesn't support CHDLC inteface
*                 types, to fix this "true type" option will set
*                 the interface type to RAW IP mode.
* Nov 07, 2000  Nenad Corbic    Added security features for UDP debugging:
*                               Deny all and specify allowed requests.
* Jun 20, 2000  Nenad Corbic    Fixed the API IP ERROR bug. Caused by the 
*                               latest update.
* May 09, 2000    Nenad Corbic    Option to bring down an interface
*                               upon disconnect.
* Mar 23, 2000  Nenad Corbic    Improved task queue, bh handling.
* Mar 16, 2000    Nenad Corbic    Fixed the SLARP Dynamic IP addressing.
* Mar 06, 2000  Nenad Corbic    Bug Fix: corrupted mbox recovery.
* Feb 10, 2000  Gideon Hack     Added ASYNC support.
* Feb 09, 2000  Nenad Corbic    Fixed two shutdown bugs in update() and
*                               if_stats() functions.
* Jan 24, 2000  Nenad Corbic    Fixed a startup wanpipe state racing,  
*                               condition between if_open and isr. 
* Jan 10, 2000  Nenad Corbic    Added new socket API support.
* Dev 15, 1999  Nenad Corbic    Fixed up header files for 2.0.X kernels
* Nov 20, 1999  Nenad Corbic     Fixed zero length API bug.
* Sep 30, 1999  Nenad Corbic    Fixed dynamic IP and route setup.
* Sep 23, 1999  Nenad Corbic    Added SMP support, fixed tracing 
* Sep 13, 1999  Nenad Corbic    Split up Port 0 and 1 into separate devices.
* Jun 02, 1999  Gideon Hack     Added support for the S514 adapter.
* Oct 30, 1998    Jaspreet Singh    Added Support for CHDLC API (HDLC STREAMING).
* Oct 28, 1998    Jaspreet Singh    Added Support for Dual Port CHDLC.
* Aug 07, 1998    David Fong    Initial version.
*****************************************************************************/

#include <linux/module.h>
#include <linux/version.h>
#include <linux/kernel.h>    /* printk(), and other useful stuff */
#include <linux/stddef.h>    /* offsetof(), etc. */
#include <linux/errno.h>    /* return codes */
#include <linux/string.h>    /* inline memset(), etc. */
#include <linux/slab.h>    /* kmalloc(), kfree() */
#include <linux/wanrouter.h>    /* WAN router definitions */
#include <linux/wanpipe.h>    /* WANPIPE common user API definitions */
#include <linux/if_arp.h>    /* ARPHRD_* defines */


#if defined(LINUX_2_1) || defined(LINUX_2_4)
 #include <asm/uaccess.h>
 #include <linux/inetdevice.h>
 #include <linux/netdevice.h>
#else                 
 #include <asm/segment.h>
 #include <net/route.h>          /* Adding new route entries : 2.0.X kernels */
#endif

#include <linux/in.h>        /* sockaddr_in */
#include <linux/inet.h>    
#include <linux/if.h>
#include <asm/byteorder.h>    /* htons(), etc. */
#include <linux/sdlapci.h>
#include <asm/io.h>

#include <linux/sdla_chdlc.h>        /* CHDLC firmware API definitions */
#include <linux/sdla_asy.h>               /* CHDLC (async) API definitions */

#include <linux/if_wanpipe_common.h>    /* Socket Driver common area */
#include <linux/if_wanpipe.h>        

/* TTY Includes */
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>


/****** Defines & Macros ****************************************************/

/* reasons for enabling the timer interrupt on the adapter */
#define TMR_INT_ENABLED_UDP           0x01
#define TMR_INT_ENABLED_UPDATE        0x02
#define TMR_INT_ENABLED_CONFIG        0x10

#define MAX_IP_ERRORS    10

#define TTY_CHDLC_MAX_MTU    2000
#define    CHDLC_DFLT_DATA_LEN    1500        /* default MTU */
#define CHDLC_HDR_LEN        1

#define CHDLC_API 0x01

#define PORT(x)   (x == 0 ? "PRIMARY" : "SECONDARY" )
#define MAX_BH_BUFF    10

//#define PRINT_DEBUG
#ifdef PRINT_DEBUG
#define dbg_printk(format, a...) printk(format, ## a)
#else
#define dbg_printk(format, a...)
#endif  

/******Data Structures*****************************************************/

/* This structure is placed in the private data area of the device structure.
 * The card structure used to occupy the private area but now the following 
 * structure will incorporate the card structure along with CHDLC specific data
 */

typedef struct chdlc_private_area
{
    wanpipe_common_t common;
    sdla_t        *card;
    int         TracingEnabled;        /* For enabling Tracing */
    unsigned long     curr_trace_addr;    /* Used for Tracing */
    unsigned long     start_trace_addr;
    unsigned long     end_trace_addr;
    unsigned long     base_addr_trace_buffer;
    unsigned long     end_addr_trace_buffer;
    unsigned short     number_trace_elements;
    unsigned      available_buffer_space;
    unsigned long     router_start_time;
    unsigned char     route_status;
    unsigned char     route_removed;
    unsigned long     tick_counter;        /* For 5s timeout counter */
    unsigned long     router_up_time;
        u32             IP_address;        /* IP addressing */
        u32             IP_netmask;
    u32        ip_local;
    u32        ip_remote;
    u32         ip_local_tmp;
    u32        ip_remote_tmp;
    u8        ip_error;
    u8        config_chdlc;
    u8         config_chdlc_timeout;
    unsigned char  mc;            /* Mulitcast support on/off */
    unsigned short udp_pkt_lgth;        /* udp packet processing */
    char udp_pkt_src;
    char udp_pkt_data[MAX_LGTH_UDP_MGNT_PKT];
    unsigned short timer_int_enabled;
    char update_comms_stats;        /* updating comms stats */

#if defined(LINUX_2_1) || defined(LINUX_2_4)
    bh_data_t *bh_head;            /* Circular buffer for chdlc_bh */
    unsigned long  tq_working;
    volatile int  bh_write;
    volatile int  bh_read;
    atomic_t  bh_buff_used;
#endif
    
    unsigned char interface_down;

    /* Polling task queue. Each interface
         * has its own task queue, which is used
         * to defer events from the interrupt */
    struct tq_struct poll_task;
    struct timer_list poll_delay_timer;

    u8 gateway;
    u8 true_if_encoding;
    //FIXME: add driver stats as per frame relay!

} chdlc_private_area_t;

/* Route Status options */
#define NO_ROUTE    0x00
#define ADD_ROUTE    0x01
#define ROUTE_ADDED    0x02
#define REMOVE_ROUTE    0x03


/* variable for keeping track of enabling/disabling FT1 monitor status */
static int rCount = 0;

/* variable for tracking how many interfaces to open for WANPIPE on the
   two ports */

extern void disable_irq(unsigned int);
extern void enable_irq(unsigned int);

/****** Function Prototypes *************************************************/
/* WAN link driver entry points. These are called by the WAN router module. */
static int update (wan_device_t* wandev);
static int new_if (wan_device_t* wandev, netdevice_t* dev,
    wanif_conf_t* conf);

/* Network device interface */
static int if_init   (netdevice_t* dev);
static int if_open   (netdevice_t* dev);
static int if_close  (netdevice_t* dev);
static int if_header (struct sk_buff* skb, netdevice_t* dev,
    unsigned short type, void* daddr, void* saddr, unsigned len);

#if defined(LINUX_2_1) || defined(LINUX_2_4)
  static int if_rebuild_hdr (struct sk_buff *skb);
  static struct net_device_stats* if_stats (netdevice_t* dev);

#else
  static int if_rebuild_hdr (void* hdr, netdevice_t* dev, unsigned long raddr,
        struct sk_buff* skb);
  static struct enet_statistics* if_stats (netdevice_t* dev);
#endif
  
static int if_send (struct sk_buff* skb, netdevice_t* dev);

/* CHDLC Firmware interface functions */
static int chdlc_configure     (sdla_t* card, void* data);
static int chdlc_comm_enable     (sdla_t* card);
static int chdlc_read_version     (sdla_t* card, char* str);
static int chdlc_set_intr_mode     (sdla_t* card, unsigned mode);
static int chdlc_send (sdla_t* card, void* data, unsigned len);
static int chdlc_read_comm_err_stats (sdla_t* card);
static int chdlc_read_op_stats (sdla_t* card);
static int chdlc_error (sdla_t *card, int err, CHDLC_MAILBOX_STRUCT *mb);


static int chdlc_disable_comm_shutdown (sdla_t *card);
#ifdef LINUX_2_4
  static void if_tx_timeout (netdevice_t *dev);
#endif

/* Miscellaneous CHDLC Functions */
static int set_chdlc_config (sdla_t* card);
static void init_chdlc_tx_rx_buff( sdla_t* card);
static int process_chdlc_exception(sdla_t *card);
static int process_global_exception(sdla_t *card);
static int update_comms_stats(sdla_t* card,
        chdlc_private_area_t* chdlc_priv_area);
static int configure_ip (sdla_t* card);
static int unconfigure_ip (sdla_t* card);
static void process_route(sdla_t *card);
static void port_set_state (sdla_t *card, int);
static int config_chdlc (sdla_t *card);
static void disable_comm (sdla_t *card);

static void trigger_chdlc_poll (netdevice_t *);
static void chdlc_poll (netdevice_t *);
static void chdlc_poll_delay (unsigned long dev_ptr);


/* Miscellaneous asynchronous interface Functions */
static int set_asy_config (sdla_t* card);
static int asy_comm_enable (sdla_t* card);

/* Interrupt handlers */
static void wpc_isr (sdla_t* card);
static void rx_intr (sdla_t* card);
static void timer_intr(sdla_t *);

#if defined(LINUX_2_1) || defined(LINUX_2_4)
  /* Bottom half handlers */
  static void chdlc_bh (netdevice_t *);
  static int chdlc_bh_cleanup (netdevice_t *);
  static int bh_enqueue (netdevice_t *, struct sk_buff *);
#endif

/* Miscellaneous functions */
static int chk_bcast_mcast_addr(sdla_t* card, netdevice_t* dev,
                struct sk_buff *skb);
static int reply_udp( unsigned char *data, unsigned int mbox_len );
static int intr_test( sdla_t* card);
static int udp_pkt_type( struct sk_buff *skb , sdla_t* card);
static int store_udp_mgmt_pkt(char udp_pkt_src, sdla_t* card,
                                struct sk_buff *skb, netdevice_t* dev,
                                chdlc_private_area_t* chdlc_priv_area);
static int process_udp_mgmt_pkt(sdla_t* card, netdevice_t* dev,  
                chdlc_private_area_t* chdlc_priv_area);
static unsigned short calc_checksum (char *, int);
static void s508_lock (sdla_t *card, unsigned long *smp_flags);
static void s508_unlock (sdla_t *card, unsigned long *smp_flags);


static int  Intr_test_counter;

/* TTY Global Definitions */

#if defined(LINUX_2_4) || defined(LINUX_2_1)

#define NR_PORTS 4
#define WAN_TTY_MAJOR 226
#define WAN_TTY_MINOR 0

#define WAN_CARD(port) (tty_card_map[port])
#define MIN_PORT 0
#define MAX_PORT NR_PORTS-1 

#define CRC_LENGTH 2

static int wanpipe_tty_init(sdla_t *card);
static void wanpipe_tty_receive(sdla_t *, unsigned, unsigned int);
static void wanpipe_tty_trigger_poll(sdla_t *card);

static struct tty_driver serial_driver, callout_driver;
static int serial_refcount=1;
static int tty_init_cnt=0;

static struct serial_state rs_table[NR_PORTS];
static struct tty_struct *serial_table[NR_PORTS];
static struct termios *serial_termios[NR_PORTS];
static struct termios *serial_termios_locked[NR_PORTS];

static char tty_driver_mode=WANOPT_TTY_SYNC;

static char *opt_decode[] = {"NONE","CRTSCTS","XONXOFF-RX",
                       "CRTSCTS XONXOFF-RX","XONXOFF-TX",
                     "CRTSCTS XONXOFF-TX","CRTSCTS XONXOFF"};
static char *p_decode[] = {"NONE","ODD","EVEN"};

static void* tty_card_map[NR_PORTS] = {NULL,NULL,NULL,NULL};

#endif


/****** Public Functions ****************************************************/

/*============================================================================
 * Cisco HDLC protocol initialization routine.
 *
 * This routine is called by the main WANPIPE module during setup.  At this
 * point adapter is completely initialized and firmware is running.
 *  o read firmware version (to make sure it's alive)
 *  o configure adapter
 *  o initialize protocol-specific fields of the adapter data space.
 *
 * Return:    0    o.k.
 *        < 0    failure.
 */
int wpc_init (sdla_t* card, wandev_conf_t* conf)
{
    unsigned char port_num;
    int err;
    unsigned long max_permitted_baud = 0;
    SHARED_MEMORY_INFO_STRUCT *flags;

    union
        {
        char str[80];
        } u;
    volatile CHDLC_MAILBOX_STRUCT* mb;
    CHDLC_MAILBOX_STRUCT* mb1;
    unsigned long timeout;

    /* Verify configuration ID */
    if (conf->config_id != WANCONFIG_CHDLC) {
        printk(KERN_INFO "%s: invalid configuration ID %u!\n",
                  card->devname, conf->config_id);
        return -EINVAL;
    }

    /* Find out which Port to use */
    if ((conf->comm_port == WANOPT_PRI) || (conf->comm_port == WANOPT_SEC)){
        if (card->next){

            if (conf->comm_port != card->next->u.c.comm_port){
                card->u.c.comm_port = conf->comm_port;
            }else{
                printk(KERN_INFO "%s: ERROR - %s port used!\n",
                            card->wandev.name, PORT(conf->comm_port));
                return -EINVAL;
            }
        }else{
            card->u.c.comm_port = conf->comm_port;
        }
    }else{
        printk(KERN_INFO "%s: ERROR - Invalid Port Selected!\n",
                            card->wandev.name);
        return -EINVAL;
    }
    

    /* Initialize protocol-specific fields */
    if(card->hw.type != SDLA_S514){

        if (card->u.c.comm_port == WANOPT_PRI){    
            card->mbox  = (void *) card->hw.dpmbase;
        }else{
            card->mbox  = (void *) card->hw.dpmbase + 
                SEC_BASE_ADDR_MB_STRUCT - PRI_BASE_ADDR_MB_STRUCT;
        }    
    }else{ 
        /* for a S514 adapter, set a pointer to the actual mailbox in the */
        /* allocated virtual memory area */
        if (card->u.c.comm_port == WANOPT_PRI){
            card->mbox = (void *) card->hw.dpmbase + PRI_BASE_ADDR_MB_STRUCT;
        }else{
            card->mbox = (void *) card->hw.dpmbase + SEC_BASE_ADDR_MB_STRUCT;
        }    
    }

    mb = mb1 = card->mbox;

    if (!card->configured){

        /* The board will place an 'I' in the return code to indicate that it is
           ready to accept commands.  We expect this to be completed in less
               than 1 second. */

        timeout = jiffies;
        while (mb->return_code != 'I')    /* Wait 1s for board to initialize */
            if ((jiffies - timeout) > 1*HZ) break;

        if (mb->return_code != 'I') {
            printk(KERN_INFO
                "%s: Initialization not completed by adapter\n",
                card->devname);
            printk(KERN_INFO "Please contact Sangoma representative.\n");
            return -EIO;
        }
    }

    /* Read firmware version.  Note that when adapter initializes, it
     * clears the mailbox, so it may appear that the first command was
     * executed successfully when in fact it was merely erased. To work
     * around this, we execute the first command twice.
     */

    if (chdlc_read_version(card, u.str))
        return -EIO;

    printk(KERN_INFO "%s: Running Cisco HDLC firmware v%s\n",
        card->devname, u.str); 

    card->isr            = &wpc_isr;
    card->poll            = NULL;
    card->exec            = NULL;
    card->wandev.update        = &update;
     card->wandev.new_if        = &new_if;
    card->wandev.del_if        = NULL;
    card->wandev.udp_port       = conf->udp_port;
    card->disable_comm        = &disable_comm;
    card->wandev.new_if_cnt = 0;

    /* reset the number of times the 'update()' proc has been called */
    card->u.c.update_call_count = 0;
    
    card->wandev.ttl = conf->ttl;
    card->wandev.interface = conf->interface; 

    if ((card->u.c.comm_port == WANOPT_SEC && conf->interface == WANOPT_V35)&&
        card->hw.type != SDLA_S514){
        printk(KERN_INFO "%s: ERROR - V35 Interface not supported on S508 %s port \n",
            card->devname, PORT(card->u.c.comm_port));
        return -EIO;
    }

    card->wandev.clocking = conf->clocking;

    port_num = card->u.c.comm_port;

    /* in API mode, we can configure for "receive only" buffering */
    if(card->hw.type == SDLA_S514) {
        card->u.c.receive_only = conf->receive_only;
        if(conf->receive_only) {
            printk(KERN_INFO
                "%s: Configured for 'receive only' mode\n",
                                card->devname);
        }
    }

    /* Setup Port Bps */

    if(card->wandev.clocking) {
        if((port_num == WANOPT_PRI) || card->u.c.receive_only) {
            /* For Primary Port 0 */
                       max_permitted_baud =
                (card->hw.type == SDLA_S514) ?
                PRI_MAX_BAUD_RATE_S514 : 
                PRI_MAX_BAUD_RATE_S508;

        }else if(port_num == WANOPT_SEC) {
            /* For Secondary Port 1 */
                        max_permitted_baud =
                               (card->hw.type == SDLA_S514) ?
                                SEC_MAX_BAUD_RATE_S514 :
                                SEC_MAX_BAUD_RATE_S508;
                        }
  
            if(conf->bps > max_permitted_baud) {
                conf->bps = max_permitted_baud;
                printk(KERN_INFO "%s: Baud too high!\n",
                    card->wandev.name);
                 printk(KERN_INFO "%s: Baud rate set to %lu bps\n", 
                    card->wandev.name, max_permitted_baud);
            }
            card->wandev.bps = conf->bps;
    }else{
            card->wandev.bps = 0;
      }

    /* Setup the Port MTU */
    if((port_num == WANOPT_PRI) || card->u.c.receive_only) {

        /* For Primary Port 0 */
        card->wandev.mtu =
            (conf->mtu >= MIN_LGTH_CHDLC_DATA_CFG) ?
            min_t(unsigned int, conf->mtu, PRI_MAX_NO_DATA_BYTES_IN_FRAME) :
            CHDLC_DFLT_DATA_LEN;
    } else if(port_num == WANOPT_SEC) { 
        /* For Secondary Port 1 */
        card->wandev.mtu =
            (conf->mtu >= MIN_LGTH_CHDLC_DATA_CFG) ?
            min_t(unsigned int, conf->mtu, SEC_MAX_NO_DATA_BYTES_IN_FRAME) :
            CHDLC_DFLT_DATA_LEN;
    }

    /* Set up the interrupt status area */
    /* Read the CHDLC Configuration and obtain: 
     *    Ptr to shared memory infor struct
         * Use this pointer to calculate the value of card->u.c.flags !
      */
    mb1->buffer_length = 0;
    mb1->command = READ_CHDLC_CONFIGURATION;
    err = sdla_exec(mb1) ? mb1->return_code : CMD_TIMEOUT;
    if(err != COMMAND_OK) {
                if(card->hw.type != SDLA_S514)
                    enable_irq(card->hw.irq);

        chdlc_error(card, err, mb1);
        return -EIO;
    }

    if(card->hw.type == SDLA_S514){
                   card->u.c.flags = (void *)(card->hw.dpmbase +
                       (((CHDLC_CONFIGURATION_STRUCT *)mb1->data)->
            ptr_shared_mem_info_struct));
        }else{
                card->u.c.flags = (void *)(card->hw.dpmbase +
                        (((CHDLC_CONFIGURATION_STRUCT *)mb1->data)->
            ptr_shared_mem_info_struct % SDLA_WINDOWSIZE));
    }

    flags = card->u.c.flags;
    
    /* This is for the ports link state */
    card->wandev.state = WAN_DUALPORT;
    card->u.c.state = WAN_DISCONNECTED;


    if (!card->wandev.piggyback){    
        int err;

        /* Perform interrupt testing */
        err = intr_test(card);

        if(err || (Intr_test_counter < MAX_INTR_TEST_COUNTER)) { 
            printk(KERN_INFO "%s: Interrupt test failed (%i)\n",
                    card->devname, Intr_test_counter);
            printk(KERN_INFO "%s: Please choose another interrupt\n",
                    card->devname);
            return -EIO;
        }
        
        printk(KERN_INFO "%s: Interrupt test passed (%i)\n", 
                card->devname, Intr_test_counter);
        card->configured = 1;
    }

    if ((card->tty_opt=conf->tty) == WANOPT_YES){
#if defined(LINUX_2_4) || defined(LINUX_2_1)    
        int err;
        card->tty_minor = conf->tty_minor;

        /* On ASYNC connections internal clocking 
         * is mandatory */
        if ((card->u.c.async_mode = conf->tty_mode)){
            card->wandev.clocking = 1;
        }
        err=wanpipe_tty_init(card);
        if (err){
            return err;
        }
#else
        printk(KERN_INFO "%s: Error: TTY driver is not supported on 2.0.X kernels!\n",
                card->devname);    
        return -EINVAL;  
#endif
    }else{
    

        if (chdlc_set_intr_mode(card, APP_INT_ON_TIMER)){
            printk (KERN_INFO "%s: 
                Failed to set interrupt triggers!\n",
                card->devname);
            return -EIO;    
            }
    
        /* Mask the Timer interrupt */
        flags->interrupt_info_struct.interrupt_permission &= 
            ~APP_INT_ON_TIMER;
    }

    /* If we are using CHDLC in backup mode, this flag will
     * indicate not to look for IP addresses in config_chdlc()*/
    card->u.c.backup = conf->backup;
    
    printk(KERN_INFO "\n");

    return 0;
}

/******* WAN Device Driver Entry Points *************************************/

/*============================================================================
 * Update device status & statistics
 * This procedure is called when updating the PROC file system and returns
 * various communications statistics. These statistics are accumulated from 3 
 * different locations:
 *     1) The 'if_stats' recorded for the device.
 *     2) Communication error statistics on the adapter.
 *      3) CHDLC operational statistics on the adapter.
 * The board level statistics are read during a timer interrupt. Note that we 
 * read the error and operational statistics during consecitive timer ticks so
 * as to minimize the time that we are inside the interrupt handler.
 *
 */
static int update (wan_device_t* wandev)
{
    sdla_t* card = wandev->private;
     netdevice_t* dev;
        volatile chdlc_private_area_t* chdlc_priv_area;
        SHARED_MEMORY_INFO_STRUCT *flags;
    unsigned long timeout;

    /* sanity checks */
    if((wandev == NULL) || (wandev->private == NULL))
        return -EFAULT;
    
    if(wandev->state == WAN_UNCONFIGURED)
        return -ENODEV;

    /* more sanity checks */
        if(!card->u.c.flags)
                return -ENODEV;

    if(test_bit(PERI_CRIT, (void*)&card->wandev.critical))
                return -EAGAIN;

    if((dev=card->wandev.dev) == NULL)
        return -ENODEV;

    if((chdlc_priv_area=dev->priv) == NULL)
        return -ENODEV;

          flags = card->u.c.flags;
           if(chdlc_priv_area->update_comms_stats){
        return -EAGAIN;
    }
            
    /* we will need 2 timer interrupts to complete the */
    /* reading of the statistics */
    chdlc_priv_area->update_comms_stats = 2;
           flags->interrupt_info_struct.interrupt_permission |= APP_INT_ON_TIMER;
    chdlc_priv_area->timer_int_enabled = TMR_INT_ENABLED_UPDATE;
  
    /* wait a maximum of 1 second for the statistics to be updated */ 
        timeout = jiffies;
        for(;;) {
        if(chdlc_priv_area->update_comms_stats == 0)
            break;
                if ((jiffies - timeout) > (1 * HZ)){
                chdlc_priv_area->update_comms_stats = 0;
             chdlc_priv_area->timer_int_enabled &=
                ~TMR_INT_ENABLED_UPDATE; 
             return -EAGAIN;
        }
        }

    return 0;
}


/*============================================================================
 * Create new logical channel.
 * This routine is called by the router when ROUTER_IFNEW IOCTL is being
 * handled.
 * o parse media- and hardware-specific configuration
 * o make sure that a new channel can be created
 * o allocate resources, if necessary
 * o prepare network device structure for registaration.
 *
 * Return:    0    o.k.
 *        < 0    failure (channel will not be created)
 */
static int new_if (wan_device_t* wandev, netdevice_t* dev, wanif_conf_t* conf)
{
    sdla_t* card = wandev->private;
    chdlc_private_area_t* chdlc_priv_area;


    printk(KERN_INFO "%s: Configuring Interface: %s\n",
            card->devname, conf->name);
 
    if ((conf->name[0] == '\0') || (strlen(conf->name) > WAN_IFNAME_SZ)) {
        printk(KERN_INFO "%s: Invalid interface name!\n",
            card->devname);
        return -EINVAL;
    }
        
    /* allocate and initialize private data */
    chdlc_priv_area = kmalloc(sizeof(chdlc_private_area_t), GFP_KERNEL);
    
    if(chdlc_priv_area == NULL) 
        return -ENOMEM;

    memset(chdlc_priv_area, 0, sizeof(chdlc_private_area_t));

    chdlc_priv_area->card = card; 
    chdlc_priv_area->common.sk = NULL;
    chdlc_priv_area->common.func = NULL;    

    /* initialize data */
    strcpy(card->u.c.if_name, conf->name);

    if(card->wandev.new_if_cnt > 0) {
                kfree(chdlc_priv_area);
        return -EEXIST;
    }

    card->wandev.new_if_cnt++;

    chdlc_priv_area->TracingEnabled = 0;
    chdlc_priv_area->route_status = NO_ROUTE;
    chdlc_priv_area->route_removed = 0;

    card->u.c.async_mode = conf->async_mode;
    
    /* setup for asynchronous mode */
    if(conf->async_mode) {
        printk(KERN_INFO "%s: Configuring for asynchronous mode\n",
            wandev->name);

        if(card->u.c.comm_port == WANOPT_PRI) {
            printk(KERN_INFO
                "%s:Asynchronous mode on secondary port only\n",
                    wandev->name);
            kfree(chdlc_priv_area);
            return -EINVAL;
        }

               if(strcmp(conf->usedby, "WANPIPE") == 0) {
            printk(KERN_INFO
                                "%s: Running in WANIPE Async Mode\n",                                                    wandev->name);
            card->u.c.usedby = WANPIPE;
        }else{
            card->u.c.usedby = API;
        }

        if(!card->wandev.clocking) {
            printk(KERN_INFO
                "%s: Asynch. clocking must be 'Internal'\n",
                wandev->name);
            kfree(chdlc_priv_area);
            return -EINVAL;
        }

        if((card->wandev.bps < MIN_ASY_BAUD_RATE) ||
            (card->wandev.bps > MAX_ASY_BAUD_RATE)) {
            printk(KERN_INFO "%s: Selected baud rate is invalid.\n",
                wandev->name);
            printk(KERN_INFO "Must be between %u and %u bps.\n",
                MIN_ASY_BAUD_RATE, MAX_ASY_BAUD_RATE);
            kfree(chdlc_priv_area);
            return -EINVAL;
        }

        card->u.c.api_options = 0;
                if (conf->asy_data_trans == WANOPT_YES) {
                        card->u.c.api_options |= ASY_RX_DATA_TRANSPARENT;
                }
        
        card->u.c.protocol_options = 0;
        if (conf->rts_hs_for_receive == WANOPT_YES) {
            card->u.c.protocol_options |= ASY_RTS_HS_FOR_RX;
            }
                if (conf->xon_xoff_hs_for_receive == WANOPT_YES) {
                        card->u.c.protocol_options |= ASY_XON_XOFF_HS_FOR_RX;
                }
                if (conf->xon_xoff_hs_for_transmit == WANOPT_YES) {
                        card->u.c.protocol_options |= ASY_XON_XOFF_HS_FOR_TX;
                }
                if (conf->dcd_hs_for_transmit == WANOPT_YES) {
                        card->u.c.protocol_options |= ASY_DCD_HS_FOR_TX;
                }
                if (conf->cts_hs_for_transmit == WANOPT_YES) {
                        card->u.c.protocol_options |= ASY_CTS_HS_FOR_TX;
                }

        card->u.c.tx_bits_per_char = conf->tx_bits_per_char;
                card->u.c.rx_bits_per_char = conf->rx_bits_per_char;
                card->u.c.stop_bits = conf->stop_bits;
        card->u.c.parity = conf->parity;
        card->u.c.break_timer = conf->break_timer;
        card->u.c.inter_char_timer = conf->inter_char_timer;
        card->u.c.rx_complete_length = conf->rx_complete_length;
        card->u.c.xon_char = conf->xon_char;

    } else {    /* setup for synchronous mode */

        card->u.c.protocol_options = 0;
        if (conf->ignore_dcd == WANOPT_YES){
            card->u.c.protocol_options |= IGNORE_DCD_FOR_LINK_STAT;
        }
        if (conf->ignore_cts == WANOPT_YES){
            card->u.c.protocol_options |= IGNORE_CTS_FOR_LINK_STAT;
        }

        if (conf->ignore_keepalive == WANOPT_YES) {
            card->u.c.protocol_options |=
                IGNORE_KPALV_FOR_LINK_STAT;
            card->u.c.kpalv_tx  = MIN_Tx_KPALV_TIMER; 
            card->u.c.kpalv_rx  = MIN_Rx_KPALV_TIMER; 
            card->u.c.kpalv_err = MIN_KPALV_ERR_TOL; 

        } else {   /* Do not ignore keepalives */
            card->u.c.kpalv_tx =
                ((conf->keepalive_tx_tmr - MIN_Tx_KPALV_TIMER)
                >= 0) ?
                   min_t(unsigned int, conf->keepalive_tx_tmr,MAX_Tx_KPALV_TIMER) :
                DEFAULT_Tx_KPALV_TIMER;

            card->u.c.kpalv_rx =
                   ((conf->keepalive_rx_tmr - MIN_Rx_KPALV_TIMER)
                >= 0) ?
                   min_t(unsigned int, conf->keepalive_rx_tmr,MAX_Rx_KPALV_TIMER) :
                DEFAULT_Rx_KPALV_TIMER;

            card->u.c.kpalv_err =
                   ((conf->keepalive_err_margin-MIN_KPALV_ERR_TOL)
                >= 0) ?
                   min_t(unsigned int, conf->keepalive_err_margin,
                MAX_KPALV_ERR_TOL) : 
                   DEFAULT_KPALV_ERR_TOL;
        }

        /* Setup slarp timer to control delay between slarps */
        card->u.c.slarp_timer = 
            ((conf->slarp_timer - MIN_SLARP_REQ_TIMER) >= 0) ?
            min_t(unsigned int, conf->slarp_timer, MAX_SLARP_REQ_TIMER) :
            DEFAULT_SLARP_REQ_TIMER;

#ifdef LINUX_2_0
        if (card->u.c.slarp_timer){
            printk(KERN_INFO 
                "%s: Error: Dynamic IP support not available for 2.0.X kernels\n",
                    card->devname);
            printk(KERN_INFO "%s:        Defaulting to Static IP addressing\n",
                        card->devname);
        }
        card->u.c.slarp_timer=0;
#endif    


        if (conf->hdlc_streaming == WANOPT_YES) {
            printk(KERN_INFO "%s: Enabling HDLC STREAMING Mode\n",
                wandev->name);
            card->u.c.protocol_options = HDLC_STREAMING_MODE;
        }

        if ((chdlc_priv_area->true_if_encoding = conf->true_if_encoding) == WANOPT_YES){
            printk(KERN_INFO 
                "%s: Enabling, true interface type encoding.\n",
                card->devname);
        }
        
            /* Setup wanpipe as a router (WANPIPE) or as an API */
        if( strcmp(conf->usedby, "WANPIPE") == 0) {

            printk(KERN_INFO "%s: Running in WANPIPE mode!\n",
                wandev->name);
            card->u.c.usedby = WANPIPE;

            /* Option to bring down the interface when 
                 * the link goes down */
            if (conf->if_down){
                set_bit(DYN_OPT_ON,&chdlc_priv_area->interface_down);
                printk(KERN_INFO 
                 "%s: Dynamic interface configuration enabled\n",
                   card->devname);
            } 

        } else if( strcmp(conf->usedby, "API") == 0) {
#if defined(LINUX_2_1) || defined(LINUX_2_4) 
            card->u.c.usedby = API;
            printk(KERN_INFO "%s: Running in API mode !\n",
                wandev->name);
#else
            printk(KERN_INFO "%s: API Mode is not supported for kernels lower than 2.2.X!\n",
                wandev->name);
            printk(KERN_INFO "%s: Please upgrade to a 2.2.X kernel fro the API support\n",
                wandev->name);
                    kfree(chdlc_priv_area);
            return -EINVAL;
#endif
        }
    }

#if defined(LINUX_2_1) || defined(LINUX_2_4)
    /* Tells us that if this interface is a
         * gateway or not */
    if ((chdlc_priv_area->gateway = conf->gateway) == WANOPT_YES){
        printk(KERN_INFO "%s: Interface %s is set as a gateway.\n",
            card->devname,card->u.c.if_name);
    }
#endif

    /* Get Multicast Information */
    chdlc_priv_area->mc = conf->mc;

    /* prepare network device data space for registration */
#ifdef LINUX_2_4
    strcpy(dev->name,card->u.c.if_name);
#else
    dev->name = (char *)kmalloc(strlen(card->u.c.if_name) + 2, GFP_KERNEL); 
    sprintf(dev->name, "%s", card->u.c.if_name);
#endif

    dev->init = &if_init;
    dev->priv = chdlc_priv_area;

    /* Initialize the polling task routine */
#ifndef LINUX_2_4
    chdlc_priv_area->poll_task.next = NULL;
#endif
    chdlc_priv_area->poll_task.sync=0;
    chdlc_priv_area->poll_task.routine = (void*)(void*)chdlc_poll;
    chdlc_priv_area->poll_task.data = dev;

    /* Initialize the polling delay timer */
    init_timer(&chdlc_priv_area->poll_delay_timer);
    chdlc_priv_area->poll_delay_timer.data = (unsigned long)dev;
    chdlc_priv_area->poll_delay_timer.function = chdlc_poll_delay;
    
    printk(KERN_INFO "\n");

    return 0;
}


/****** Network Device Interface ********************************************/

/*============================================================================
 * Initialize Linux network interface.
 *
 * This routine is called only once for each interface, during Linux network
 * interface registration.  Returning anything but zero will fail interface
 * registration.
 */
static int if_init (netdevice_t* dev)
    {
    chdlc_private_area_t* chdlc_priv_area = dev->priv;
    sdla_t* card = chdlc_priv_area->card;
    wan_device_t* wandev = &card->wandev;
#ifdef LINUX_2_0
    int i;
#endif

    /* Initialize device driver entry points */
    dev->open        = &if_open;
    dev->stop        = &if_close;
    dev->hard_header    = &if_header;
    dev->rebuild_header    = &if_rebuild_hdr;
    dev->hard_start_xmit    = &if_send;
    dev->get_stats        = &if_stats;
#ifdef LINUX_2_4
    dev->tx_timeout        = &if_tx_timeout;
    dev->watchdog_timeo    = TX_TIMEOUT;
#endif

    
    /* Initialize media-specific parameters */
    dev->flags        |= IFF_POINTOPOINT;
    dev->flags        |= IFF_NOARP;

    /* Enable Mulitcasting if user selected */
    if (chdlc_priv_area->mc == WANOPT_YES){
        dev->flags     |= IFF_MULTICAST;
    }
    
#ifdef LINUX_2_0
    dev->family        = AF_INET;
#endif    

    if (chdlc_priv_area->true_if_encoding){
#if defined(LINUX_2_1) || defined(LINUX_2_4)
        dev->type    = ARPHRD_HDLC; /* This breaks the tcpdump */
#else
        dev->type    = ARPHRD_PPP;
#endif
    }else{
        dev->type    = ARPHRD_PPP;
    }
    
    dev->mtu        = card->wandev.mtu;
    /* for API usage, add the API header size to the requested MTU size */
    if(card->u.c.usedby == API) {
        dev->mtu += sizeof(api_tx_hdr_t);
    }
 
    dev->hard_header_len    = CHDLC_HDR_LEN;

    /* Initialize hardware parameters */
    dev->irq    = wandev->irq;
    dev->dma    = wandev->dma;
    dev->base_addr    = wandev->ioport;
    dev->mem_start    = wandev->maddr;
    dev->mem_end    = wandev->maddr + wandev->msize - 1;

    /* Set transmit buffer queue length 
     * If too low packets will not be retransmitted 
         * by stack.
     */
        dev->tx_queue_len = 100;
   
    /* Initialize socket buffers */
#if !defined(LINUX_2_1) && !defined(LINUX_2_4)
        for (i = 0; i < DEV_NUMBUFFS; ++i)
                skb_queue_head_init(&dev->buffs[i]);
#endif
    return 0;
}

/*============================================================================
 * Open network interface.
 * o enable communications and interrupts.
 * o prevent module from unloading by incrementing use count
 *
 * Return 0 if O.k. or errno.
 */
static int if_open (netdevice_t* dev)
{
    chdlc_private_area_t* chdlc_priv_area = dev->priv;
    sdla_t* card = chdlc_priv_area->card;
    struct timeval tv;
    int err = 0;

    /* Only one open per interface is allowed */

    if (is_dev_running(dev))
        return -EBUSY;

#if defined(LINUX_2_1) || defined(LINUX_2_4)
    /* Initialize the task queue */
    chdlc_priv_area->tq_working=0;

#ifndef LINUX_2_4
    chdlc_priv_area->common.wanpipe_task.next = NULL;
#endif
    chdlc_priv_area->common.wanpipe_task.sync = 0;
    chdlc_priv_area->common.wanpipe_task.routine = (void *)(void *)chdlc_bh;
    chdlc_priv_area->common.wanpipe_task.data = dev;

    /* Allocate and initialize BH circular buffer */
    /* Add 1 to MAX_BH_BUFF so we don't have test with (MAX_BH_BUFF-1) */
    chdlc_priv_area->bh_head = kmalloc((sizeof(bh_data_t)*(MAX_BH_BUFF+1)),GFP_ATOMIC);
    memset(chdlc_priv_area->bh_head,0,(sizeof(bh_data_t)*(MAX_BH_BUFF+1)));
    atomic_set(&chdlc_priv_area->bh_buff_used, 0);
#endif
 
    do_gettimeofday(&tv);
    chdlc_priv_area->router_start_time = tv.tv_sec;

#ifdef LINUX_2_4
    netif_start_queue(dev);
#else
    dev->interrupt = 0;
    dev->tbusy = 0;
    dev->start = 1;
#endif

    wanpipe_open(card);

    /* TTY is configured during wanpipe_set_termios
     * call, not here */
    if (card->tty_opt)
        return err;
    
    set_bit(0,&chdlc_priv_area->config_chdlc);
    chdlc_priv_area->config_chdlc_timeout=jiffies;
    del_timer(&chdlc_priv_area->poll_delay_timer);

    /* Start the CHDLC configuration after 1sec delay.
     * This will give the interface initilization time
     * to finish its configuration */
    chdlc_priv_area->poll_delay_timer.expires=jiffies+HZ;
    add_timer(&chdlc_priv_area->poll_delay_timer);
    return err;
}

/*============================================================================
 * Close network interface.
 * o if this is the last close, then disable communications and interrupts.
 * o reset flags.
 */
static int if_close (netdevice_t* dev)
{
    chdlc_private_area_t* chdlc_priv_area = dev->priv;
    sdla_t* card = chdlc_priv_area->card;

#if defined(LINUX_2_1) || defined(LINUX_2_4)

    if (chdlc_priv_area->bh_head){
        int i;
        struct sk_buff *skb;
    
        for (i=0; i<(MAX_BH_BUFF+1); i++){
            skb = ((bh_data_t *)&chdlc_priv_area->bh_head[i])->skb;
            if (skb != NULL){
                        wan_dev_kfree_skb(skb, FREE_READ);
            }
        }
        kfree(chdlc_priv_area->bh_head);
        chdlc_priv_area->bh_head=NULL;
    }
#endif

    stop_net_queue(dev);
#ifndef LINUX_2_4
    dev->start=0;
#endif
    wanpipe_close(card);
    del_timer(&chdlc_priv_area->poll_delay_timer);
    return 0;
}

static void disable_comm (sdla_t *card)
{
    SHARED_MEMORY_INFO_STRUCT *flags = card->u.c.flags;
    
    if (card->u.c.comm_enabled){
        chdlc_disable_comm_shutdown (card);
    }else{
        flags->interrupt_info_struct.interrupt_permission = 0;    
    }

#if defined(LINUX_2_4) || defined(LINUX_2_1)    
    if (!tty_init_cnt)
        return;

    if (card->tty_opt){
        struct serial_state * state;
        if (!(--tty_init_cnt)){
            int e1,e2;
            *serial_driver.refcount=0;
            
            if ((e1 = tty_unregister_driver(&serial_driver)))
                printk("SERIAL: failed to unregister serial driver (%d)\n",
                       e1);
            if ((e2 = tty_unregister_driver(&callout_driver)))
                printk("SERIAL: failed to unregister callout driver (%d)\n", 
                       e2);
            printk(KERN_INFO "%s: Unregistering TTY Driver, Major %i\n",
                    card->devname,WAN_TTY_MAJOR);
        }
        card->tty=NULL;
        tty_card_map[card->tty_minor]=NULL;
        state = &rs_table[card->tty_minor];
        memset(state,0,sizeof(state));
    }
#endif
    return;
}


/*============================================================================
 * Build media header.
 *
 * The trick here is to put packet type (Ethertype) into 'protocol' field of
 * the socket buffer, so that we don't forget it.  If packet type is not
 * supported, set skb->protocol to 0 and discard packet later.
 *
 * Return:    media header length.
 */
static int if_header (struct sk_buff* skb, netdevice_t* dev,
    unsigned short type, void* daddr, void* saddr, unsigned len)
{
    skb->protocol = htons(type);

    return CHDLC_HDR_LEN;
}


#ifdef LINUX_2_4
/*============================================================================
 * Handle transmit timeout event from netif watchdog
 */
static void if_tx_timeout (netdevice_t *dev)
{
        chdlc_private_area_t* chan = dev->priv;
    sdla_t *card = chan->card;
    
    /* If our device stays busy for at least 5 seconds then we will
     * kick start the device by making dev->tbusy = 0.  We expect
     * that our device never stays busy more than 5 seconds. So this                 
     * is only used as a last resort.
     */

    ++card->wandev.stats.collisions;

    printk (KERN_INFO "%s: Transmit timed out on %s\n", card->devname,dev->name);
    netif_wake_queue (dev);
}
#endif



/*============================================================================
 * Re-build media header.
 *
 * Return:    1    physical address resolved.
 *        0    physical address not resolved
 */
#if defined(LINUX_2_1) || defined(LINUX_2_4)
static int if_rebuild_hdr (struct sk_buff *skb)
{
    return 1;
}
#else
static int if_rebuild_hdr (void* hdr, netdevice_t* dev, unsigned long raddr,
                           struct sk_buff* skb)
{
        return 1;
}
#endif

/*============================================================================
 * Send a packet on a network interface.
 * o set tbusy flag (marks start of the transmission) to block a timer-based
 *   transmit from overlapping.
 * o check link state. If link is not up, then drop the packet.
 * o execute adapter send command.
 * o free socket buffer
 *
 * Return:    0    complete (socket buffer must be freed)
 *        non-0    packet may be re-transmitted (tbusy must be set)
 *
 * Notes:
 * 1. This routine is called either by the protocol stack or by the "net
 *    bottom half" (with interrupts enabled).
 * 2. Setting tbusy flag will inhibit further transmit requests from the
 *    protocol stack and can be used for flow control with protocol layer.
 */
static int if_send (struct sk_buff* skb, netdevice_t* dev)
{
    chdlc_private_area_t *chdlc_priv_area = dev->priv;
    sdla_t *card = chdlc_priv_area->card;
    SHARED_MEMORY_INFO_STRUCT *flags = card->u.c.flags;
    INTERRUPT_INFORMATION_STRUCT *chdlc_int = &flags->interrupt_info_struct;
    int udp_type = 0;
    unsigned long smp_flags;
    int err=0;

#ifdef LINUX_2_4
    netif_stop_queue(dev);
#endif
    
    if (skb == NULL){
        /* If we get here, some higher layer thinks we've missed an
         * tx-done interrupt.
         */
        printk(KERN_INFO "%s: interface %s got kicked!\n",
            card->devname, dev->name);

        wake_net_dev(dev);
        return 0;
    }

#ifndef LINUX_2_4
    if (dev->tbusy){

        /* If our device stays busy for at least 5 seconds then we will
         * kick start the device by making dev->tbusy = 0.  We expect 
         * that our device never stays busy more than 5 seconds. So this
         * is only used as a last resort. 
         */
                ++card->wandev.stats.collisions;
        if((jiffies - chdlc_priv_area->tick_counter) < (5 * HZ)) {
            return 1;
        }

        printk (KERN_INFO "%s: Transmit timeout !\n",
            card->devname);

        /* unbusy the interface */
        clear_bit(0,&dev->tbusy);
    }
#endif

       if (ntohs(skb->protocol) != htons(PVC_PROT)){

        /* check the udp packet type */
        
        udp_type = udp_pkt_type(skb, card);

        if (udp_type == UDP_CPIPE_TYPE){
                        if(store_udp_mgmt_pkt(UDP_PKT_FRM_STACK, card, skb, dev,
                                chdlc_priv_area)){
                        chdlc_int->interrupt_permission |=
                    APP_INT_ON_TIMER;
            }
            start_net_queue(dev);
            return 0;
        }

        /* check to see if the source IP address is a broadcast or */
        /* multicast IP address */
                if(chk_bcast_mcast_addr(card, dev, skb)){
            ++card->wandev.stats.tx_dropped;
            wan_dev_kfree_skb(skb,FREE_WRITE);
            start_net_queue(dev);
            return 0;
        }
        }

    /* Lock the 508 Card: SMP is supported */
          if(card->hw.type != SDLA_S514){
        s508_lock(card,&smp_flags);
    } 

        if(test_and_set_bit(SEND_CRIT, (void*)&card->wandev.critical)) {
    
        printk(KERN_INFO "%s: Critical in if_send: %lx\n",
                    card->wandev.name,card->wandev.critical);
                ++card->wandev.stats.tx_dropped;
        start_net_queue(dev);
        goto if_send_exit_crit;
    }

    if(card->u.c.state != WAN_CONNECTED){
               ++card->wandev.stats.tx_dropped;
        start_net_queue(dev);
        
    }else if(!skb->protocol){
            ++card->wandev.stats.tx_errors;
        start_net_queue(dev);
        
    }else {
        void* data = skb->data;
        unsigned len = skb->len;
        unsigned char attr;

        /* If it's an API packet pull off the API
         * header. Also check that the packet size
         * is larger than the API header
             */
        if (card->u.c.usedby == API){
            api_tx_hdr_t* api_tx_hdr;

            /* discard the frame if we are configured for */
            /* 'receive only' mode or if there is no data */
            if (card->u.c.receive_only ||
                (len <= sizeof(api_tx_hdr_t))) {
                
                ++card->wandev.stats.tx_dropped;
                start_net_queue(dev);
                goto if_send_exit_crit;
            }
                
            api_tx_hdr = (api_tx_hdr_t *)data;
            attr = api_tx_hdr->attr;
            data += sizeof(api_tx_hdr_t);
            len -= sizeof(api_tx_hdr_t);
        }

        if(chdlc_send(card, data, len)) {
            stop_net_queue(dev);
        }else{
            ++card->wandev.stats.tx_packets;
#if defined(LINUX_2_1) || defined(LINUX_2_4)
                        card->wandev.stats.tx_bytes += len;
#endif
            
            start_net_queue(dev);
            
#ifdef LINUX_2_4
             dev->trans_start = jiffies;
#endif
        }    
    }

if_send_exit_crit:
    
    if (!(err=is_queue_stopped(dev))) {
        wan_dev_kfree_skb(skb, FREE_WRITE);
    }else{
        chdlc_priv_area->tick_counter = jiffies;
        chdlc_int->interrupt_permission |= APP_INT_ON_TX_FRAME;
    }

    clear_bit(SEND_CRIT, (void*)&card->wandev.critical);
    if(card->hw.type != SDLA_S514){
        s508_unlock(card,&smp_flags);
    }
    
    return err;
}


/*============================================================================
 * Check to see if the packet to be transmitted contains a broadcast or
 * multicast source IP address.
 */

static int chk_bcast_mcast_addr(sdla_t *card, netdevice_t* dev,
                struct sk_buff *skb)
{
    u32 src_ip_addr;
        u32 broadcast_ip_addr = 0;
#if defined(LINUX_2_1) || defined(LINUX_2_4)
        struct in_device *in_dev;
#endif
        /* read the IP source address from the outgoing packet */
        src_ip_addr = *(u32 *)(skb->data + 12);

    /* read the IP broadcast address for the device */
#if defined(LINUX_2_1) || defined(LINUX_2_4)
        in_dev = dev->ip_ptr;
        if(in_dev != NULL) {
                struct in_ifaddr *ifa= in_dev->ifa_list;
                if(ifa != NULL)
                        broadcast_ip_addr = ifa->ifa_broadcast;
                else
                        return 0;
        }
#else
        broadcast_ip_addr = dev->pa_brdaddr;
#endif
 
        /* check if the IP Source Address is a Broadcast address */
        if((dev->flags & IFF_BROADCAST) && (src_ip_addr == broadcast_ip_addr)) {
                printk(KERN_INFO "%s: Broadcast Source Address silently discarded\n",
                card->devname);
                return 1;
        } 

        /* check if the IP Source Address is a Multicast address */
        if((ntohl(src_ip_addr) >= 0xE0000001) &&
        (ntohl(src_ip_addr) <= 0xFFFFFFFE)) {
                printk(KERN_INFO "%s: Multicast Source Address silently discarded\n",
                card->devname);
                return 1;
        }

        return 0;
}


/*============================================================================
 * Reply to UDP Management system.
 * Return length of reply.
 */
static int reply_udp( unsigned char *data, unsigned int mbox_len )
{

    unsigned short len, udp_length, temp, ip_length;
    unsigned long ip_temp;
    int even_bound = 0;
      chdlc_udp_pkt_t *c_udp_pkt = (chdlc_udp_pkt_t *)data;
     
    /* Set length of packet */
    len = sizeof(ip_pkt_t)+ 
          sizeof(udp_pkt_t)+
          sizeof(wp_mgmt_t)+
          sizeof(cblock_t)+
          sizeof(trace_info_t)+ 
          mbox_len;

    /* fill in UDP reply */
    c_udp_pkt->wp_mgmt.request_reply = UDPMGMT_REPLY;
   
    /* fill in UDP length */
    udp_length = sizeof(udp_pkt_t)+ 
             sizeof(wp_mgmt_t)+
             sizeof(cblock_t)+
                 sizeof(trace_info_t)+
             mbox_len; 

     /* put it on an even boundary */
    if ( udp_length & 0x0001 ) {
        udp_length += 1;
        len += 1;
        even_bound = 1;
    }  

    temp = (udp_length<<8)|(udp_length>>8);
    c_udp_pkt->udp_pkt.udp_length = temp;
         
    /* swap UDP ports */
    temp = c_udp_pkt->udp_pkt.udp_src_port;
    c_udp_pkt->udp_pkt.udp_src_port = 
            c_udp_pkt->udp_pkt.udp_dst_port; 
    c_udp_pkt->udp_pkt.udp_dst_port = temp;

    /* add UDP pseudo header */
    temp = 0x1100;
    *((unsigned short *)(c_udp_pkt->data+mbox_len+even_bound)) = temp;    
    temp = (udp_length<<8)|(udp_length>>8);
    *((unsigned short *)(c_udp_pkt->data+mbox_len+even_bound+2)) = temp;

         
    /* calculate UDP checksum */
    c_udp_pkt->udp_pkt.udp_checksum = 0;
    c_udp_pkt->udp_pkt.udp_checksum = calc_checksum(&data[UDP_OFFSET],udp_length+UDP_OFFSET);

    /* fill in IP length */
    ip_length = len;
    temp = (ip_length<<8)|(ip_length>>8);
    c_udp_pkt->ip_pkt.total_length = temp;
  
    /* swap IP addresses */
    ip_temp = c_udp_pkt->ip_pkt.ip_src_address;
    c_udp_pkt->ip_pkt.ip_src_address = c_udp_pkt->ip_pkt.ip_dst_address;
    c_udp_pkt->ip_pkt.ip_dst_address = ip_temp;

    /* fill in IP checksum */
    c_udp_pkt->ip_pkt.hdr_checksum = 0;
    c_udp_pkt->ip_pkt.hdr_checksum = calc_checksum(data,sizeof(ip_pkt_t));

    return len;

} /* reply_udp */

unsigned short calc_checksum (char *data, int len)
{
    unsigned short temp; 
    unsigned long sum=0;
    int i;

    for( i = 0; i <len; i+=2 ) {
        memcpy(&temp,&data[i],2);
        sum += (unsigned long)temp;
    }

    while (sum >> 16 ) {
        sum = (sum & 0xffffUL) + (sum >> 16);
    }

    temp = (unsigned short)sum;
    temp = ~temp;

    if( temp == 0 ) 
        temp = 0xffff;

    return temp;    
}


/*============================================================================
 * Get ethernet-style interface statistics.
 * Return a pointer to struct enet_statistics.
 */
#if defined(LINUX_2_1) || defined(LINUX_2_4)
static struct net_device_stats* if_stats (netdevice_t* dev)
{
    sdla_t *my_card;
    chdlc_private_area_t* chdlc_priv_area;

    if ((chdlc_priv_area=dev->priv) == NULL)
        return NULL;

    my_card = chdlc_priv_area->card;
    return &my_card->wandev.stats; 
}
#else
static struct enet_statistics* if_stats (netdevice_t* dev)
{
        sdla_t *my_card;
        chdlc_private_area_t* chdlc_priv_area = dev->priv;

    if ((chdlc_priv_area=dev->priv) == NULL)
        return NULL;

        my_card = chdlc_priv_area->card;
        return &my_card->wandev.stats;
}
#endif

/****** Cisco HDLC Firmware Interface Functions *******************************/

/*============================================================================
 * Read firmware code version.
 *    Put code version as ASCII string in str. 
 */
static int chdlc_read_version (sdla_t* card, char* str)
{
    CHDLC_MAILBOX_STRUCT* mb = card->mbox;
    int len;
    char err;
    mb->buffer_length = 0;
    mb->command = READ_CHDLC_CODE_VERSION;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;

    if(err != COMMAND_OK) {
        chdlc_error(card,err,mb);
    }
    else if (str) {  /* is not null */
        len = mb->buffer_length;
        memcpy(str, mb->data, len);
        str[len] = '\0';
    }
    return (err);
}

/*-----------------------------------------------------------------------------
 *  Configure CHDLC firmware.
 */
static int chdlc_configure (sdla_t* card, void* data)
{
    int err;
    CHDLC_MAILBOX_STRUCT *mailbox = card->mbox;
    int data_length = sizeof(CHDLC_CONFIGURATION_STRUCT);
    
    mailbox->buffer_length = data_length;  
    memcpy(mailbox->data, data, data_length);
    mailbox->command = SET_CHDLC_CONFIGURATION;
    err = sdla_exec(mailbox) ? mailbox->return_code : CMD_TIMEOUT;
    
    if (err != COMMAND_OK) chdlc_error (card, err, mailbox);
                           
    return err;
}


/*============================================================================
 * Set interrupt mode -- HDLC Version.
 */

static int chdlc_set_intr_mode (sdla_t* card, unsigned mode)
{
    CHDLC_MAILBOX_STRUCT* mb = card->mbox;
    CHDLC_INT_TRIGGERS_STRUCT* int_data =
         (CHDLC_INT_TRIGGERS_STRUCT *)mb->data;
    int err;

    int_data->CHDLC_interrupt_triggers     = mode;
    int_data->IRQ                = card->hw.irq;
    int_data->interrupt_timer               = 1;
   
    mb->buffer_length = sizeof(CHDLC_INT_TRIGGERS_STRUCT);
    mb->command = SET_CHDLC_INTERRUPT_TRIGGERS;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
    if (err != COMMAND_OK)
        chdlc_error (card, err, mb);
    return err;
}


/*===========================================================
 * chdlc_disable_comm_shutdown
 *
 * Shutdown() disables the communications. We must
 * have a sparate functions, because we must not
 * call chdlc_error() hander since the private
 * area has already been replaced */

static int chdlc_disable_comm_shutdown (sdla_t *card)
{
    CHDLC_MAILBOX_STRUCT* mb = card->mbox;
    CHDLC_INT_TRIGGERS_STRUCT* int_data =
         (CHDLC_INT_TRIGGERS_STRUCT *)mb->data;
    int err;

    /* Disable Interrutps */
    int_data->CHDLC_interrupt_triggers     = 0;
    int_data->IRQ                = card->hw.irq;
    int_data->interrupt_timer               = 1;
   
    mb->buffer_length = sizeof(CHDLC_INT_TRIGGERS_STRUCT);
    mb->command = SET_CHDLC_INTERRUPT_TRIGGERS;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;

    /* Disable Communications */

    if (card->u.c.async_mode) {
        mb->command = DISABLE_ASY_COMMUNICATIONS;
    }else{
        mb->command = DISABLE_CHDLC_COMMUNICATIONS;
    }
    
    mb->buffer_length = 0;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
    
    card->u.c.comm_enabled = 0;
    
    return 0;
}

/*============================================================================
 * Enable communications.
 */

static int chdlc_comm_enable (sdla_t* card)
{
    int err;
    CHDLC_MAILBOX_STRUCT* mb = card->mbox;

    mb->buffer_length = 0;
    mb->command = ENABLE_CHDLC_COMMUNICATIONS;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
    if (err != COMMAND_OK)
        chdlc_error(card, err, mb);
    else
        card->u.c.comm_enabled = 1;
    
    return err;
}

/*============================================================================
 * Read communication error statistics.
 */
static int chdlc_read_comm_err_stats (sdla_t* card)
{
        int err;
        CHDLC_MAILBOX_STRUCT* mb = card->mbox;

        mb->buffer_length = 0;
        mb->command = READ_COMMS_ERROR_STATS;
        err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
        if (err != COMMAND_OK)
                chdlc_error(card,err,mb);
        return err;
}


/*============================================================================
 * Read CHDLC operational statistics.
 */
static int chdlc_read_op_stats (sdla_t* card)
{
        int err;
        CHDLC_MAILBOX_STRUCT* mb = card->mbox;

        mb->buffer_length = 0;
        mb->command = READ_CHDLC_OPERATIONAL_STATS;
        err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
        if (err != COMMAND_OK)
                chdlc_error(card,err,mb);
        return err;
}


/*============================================================================
 * Update communications error and general packet statistics.
 */
static int update_comms_stats(sdla_t* card,
    chdlc_private_area_t* chdlc_priv_area)
{
        CHDLC_MAILBOX_STRUCT* mb = card->mbox;
      COMMS_ERROR_STATS_STRUCT* err_stats;
        CHDLC_OPERATIONAL_STATS_STRUCT *op_stats;

    /* on the first timer interrupt, read the comms error statistics */
    if(chdlc_priv_area->update_comms_stats == 2) {
        if(chdlc_read_comm_err_stats(card))
            return 1;
        err_stats = (COMMS_ERROR_STATS_STRUCT *)mb->data;
        card->wandev.stats.rx_over_errors = 
                err_stats->Rx_overrun_err_count;
        card->wandev.stats.rx_crc_errors = 
                err_stats->CRC_err_count;
        card->wandev.stats.rx_frame_errors = 
                err_stats->Rx_abort_count;
        card->wandev.stats.rx_fifo_errors = 
                err_stats->Rx_dis_pri_bfrs_full_count; 
        card->wandev.stats.rx_missed_errors =
                card->wandev.stats.rx_fifo_errors;
        card->wandev.stats.tx_aborted_errors =
                err_stats->sec_Tx_abort_count;
    }

        /* on the second timer interrupt, read the operational statistics */
    else {
            if(chdlc_read_op_stats(card))
                    return 1;
        op_stats = (CHDLC_OPERATIONAL_STATS_STRUCT *)mb->data;
        card->wandev.stats.rx_length_errors =
            (op_stats->Rx_Data_discard_short_count +
            op_stats->Rx_Data_discard_long_count);
    }

    return 0;
}

/*============================================================================
 * Send packet.
 *    Return:    0 - o.k.
 *        1 - no transmit buffers available
 */
static int chdlc_send (sdla_t* card, void* data, unsigned len)
{
    CHDLC_DATA_TX_STATUS_EL_STRUCT *txbuf = card->u.c.txbuf;

    if (txbuf->opp_flag)
        return 1;
    
    sdla_poke(&card->hw, txbuf->ptr_data_bfr, data, len);

    txbuf->frame_length = len;
    txbuf->opp_flag = 1;        /* start transmission */
    
    /* Update transmit buffer control fields */
    card->u.c.txbuf = ++txbuf;
    
    if ((void*)txbuf > card->u.c.txbuf_last)
        card->u.c.txbuf = card->u.c.txbuf_base;
    
    return 0;
}

/****** Firmware Error Handler **********************************************/

/*============================================================================
 * Firmware error handler.
 *    This routine is called whenever firmware command returns non-zero
 *    return code.
 *
 * Return zero if previous command has to be cancelled.
 */
static int chdlc_error (sdla_t *card, int err, CHDLC_MAILBOX_STRUCT *mb)
{
    unsigned cmd = mb->command;

    switch (err) {

    case CMD_TIMEOUT:
        printk(KERN_INFO "%s: command 0x%02X timed out!\n",
            card->devname, cmd);
        break;

    case S514_BOTH_PORTS_SAME_CLK_MODE:
        if(cmd == SET_CHDLC_CONFIGURATION) {
            printk(KERN_INFO
             "%s: Configure both ports for the same clock source\n",
                card->devname);
            break;
        }

    default:
        printk(KERN_INFO "%s: command 0x%02X returned 0x%02X!\n",
            card->devname, cmd, err);
    }

    return 0;
}

#if defined(LINUX_2_1) || defined(LINUX_2_4)
/********** Bottom Half Handlers ********************************************/

/* NOTE: There is no API, BH support for Kernels lower than 2.2.X.
 *       DO NOT INSERT ANY CODE HERE, NOTICE THE 
 *       PREPROCESSOR STATEMENT ABOVE, UNLESS YOU KNOW WHAT YOU ARE
 *       DOING */

static void chdlc_bh (netdevice_t * dev)
{
    chdlc_private_area_t* chan = dev->priv;
    sdla_t *card = chan->card;
    struct sk_buff *skb;

    if (atomic_read(&chan->bh_buff_used) == 0){
        clear_bit(0, &chan->tq_working);
        return;
    }

    while (atomic_read(&chan->bh_buff_used)){

        skb  = ((bh_data_t *)&chan->bh_head[chan->bh_read])->skb;

        if (skb != NULL){

            if (chan->common.sk == NULL || chan->common.func == NULL){
                ++card->wandev.stats.rx_dropped;
                wan_dev_kfree_skb(skb, FREE_READ);
                chdlc_bh_cleanup(dev);
                continue;
            }

            if (chan->common.func(skb,dev,chan->common.sk) != 0){
                /* Sock full cannot send, queue us for another
                                 * try */
                atomic_set(&chan->common.receive_block,1);
                return;
            }else{
                chdlc_bh_cleanup(dev);
            }
        }else{
            chdlc_bh_cleanup(dev);
        }
    }    
    clear_bit(0, &chan->tq_working);

    return;
}

static int chdlc_bh_cleanup (netdevice_t *dev)
{
    chdlc_private_area_t* chan = dev->priv;

    ((bh_data_t *)&chan->bh_head[chan->bh_read])->skb = NULL;

    if (chan->bh_read == MAX_BH_BUFF){
        chan->bh_read=0;
    }else{
        ++chan->bh_read;    
    }

    atomic_dec(&chan->bh_buff_used);
    return 0;
}



static int bh_enqueue (netdevice_t *dev, struct sk_buff *skb)
{
    /* Check for full */
    chdlc_private_area_t* chan = dev->priv;
    sdla_t *card = chan->card;

    if (atomic_read(&chan->bh_buff_used) == (MAX_BH_BUFF+1)){
        ++card->wandev.stats.rx_dropped;
        wan_dev_kfree_skb(skb, FREE_READ);
        return 1; 
    }

    ((bh_data_t *)&chan->bh_head[chan->bh_write])->skb = skb;

    if (chan->bh_write == MAX_BH_BUFF){
        chan->bh_write=0;
    }else{
        ++chan->bh_write;
    }

    atomic_inc(&chan->bh_buff_used);

    return 0;
}

/* END OF API BH Support */

#endif

/****** Interrupt Handlers **************************************************/

/*============================================================================
 * Cisco HDLC interrupt service routine.
 */
static void wpc_isr (sdla_t* card)
{
    netdevice_t* dev;
    SHARED_MEMORY_INFO_STRUCT* flags = NULL;
    int i;
    sdla_t *my_card;


    /* Check for which port the interrupt has been generated
     * Since Secondary Port is piggybacking on the Primary
         * the check must be done here. 
     */

    flags = card->u.c.flags;
    if (!flags->interrupt_info_struct.interrupt_type){
        /* Check for a second port (piggybacking) */
        if ((my_card = card->next)){
            flags = my_card->u.c.flags;
            if (flags->interrupt_info_struct.interrupt_type){
                card = my_card;
                card->isr(card);
                return;
            }
        }
    }

    flags = card->u.c.flags;
    card->in_isr = 1;
    dev = card->wandev.dev;
    
    /* If we get an interrupt with no network device, stop the interrupts
     * and issue an error */
    if (!card->tty_opt && !dev && 
        flags->interrupt_info_struct.interrupt_type != 
            COMMAND_COMPLETE_APP_INT_PEND){

        goto isr_done;
    }
    
    /* if critical due to peripheral operations
     * ie. update() or getstats() then reset the interrupt and
     * wait for the board to retrigger.
     */
    if(test_bit(PERI_CRIT, (void*)&card->wandev.critical)) {
        printk(KERN_INFO "ISR CRIT TO PERI\n");
        goto isr_done;
    }

    /* On a 508 Card, if critical due to if_send 
         * Major Error !!! */
    if(card->hw.type != SDLA_S514) {
        if(test_bit(SEND_CRIT, (void*)&card->wandev.critical)) {
            printk(KERN_INFO "%s: Critical while in ISR: %lx\n",
                card->devname, card->wandev.critical);
            card->in_isr = 0;
            flags->interrupt_info_struct.interrupt_type = 0;
            return;
        }
    }

    switch(flags->interrupt_info_struct.interrupt_type) {

    case RX_APP_INT_PEND:    /* 0x01: receive interrupt */
        rx_intr(card);
        break;

    case TX_APP_INT_PEND:    /* 0x02: transmit interrupt */
        flags->interrupt_info_struct.interrupt_permission &=
             ~APP_INT_ON_TX_FRAME;

#if defined(LINUX_2_1) || defined(LINUX_2_4)

        if (card->tty_opt){
            wanpipe_tty_trigger_poll(card);
            break;
        }

        if (dev && is_queue_stopped(dev)){
            if (card->u.c.usedby == API){
                start_net_queue(dev);
                wakeup_sk_bh(dev);
            }else{
                wake_net_dev(dev);
            }
        }
#else
        wake_net_dev(dev);
#endif
        break;

    case COMMAND_COMPLETE_APP_INT_PEND:/* 0x04: cmd cplt */
        ++ Intr_test_counter;
        break;

    case CHDLC_EXCEP_COND_APP_INT_PEND:    /* 0x20 */
        process_chdlc_exception(card);
        break;

    case GLOBAL_EXCEP_COND_APP_INT_PEND:
        process_global_exception(card);
        break;

    case TIMER_APP_INT_PEND:
        timer_intr(card);
        break;

    default:
        printk(KERN_INFO "%s: spurious interrupt 0x%02X!\n", 
            card->devname,
            flags->interrupt_info_struct.interrupt_type);
        printk(KERN_INFO "Code name: ");
        for(i = 0; i < 4; i ++)
            printk(KERN_INFO "%c",
                flags->global_info_struct.codename[i]); 
        printk(KERN_INFO "\nCode version: ");
         for(i = 0; i < 4; i ++)
            printk(KERN_INFO "%c", 
                flags->global_info_struct.codeversion[i]); 
        printk(KERN_INFO "\n");    
        break;
    }

isr_done:

    card->in_isr = 0;
    flags->interrupt_info_struct.interrupt_type = 0;
    return;
}

/*============================================================================
 * Receive interrupt handler.
 */
static void rx_intr (sdla_t* card)
{
    netdevice_t *dev;
    chdlc_private_area_t *chdlc_priv_area;
    SHARED_MEMORY_INFO_STRUCT *flags = card->u.c.flags;
    CHDLC_DATA_RX_STATUS_EL_STRUCT *rxbuf = card->u.c.rxmb;
    struct sk_buff *skb;
    unsigned len;
    unsigned addr = rxbuf->ptr_data_bfr;
    void *buf;
    int i,udp_type;

    if (rxbuf->opp_flag != 0x01) {
        printk(KERN_INFO 
            "%s: corrupted Rx buffer @ 0x%X, flag = 0x%02X!\n", 
            card->devname, (unsigned)rxbuf, rxbuf->opp_flag);
                printk(KERN_INFO "Code name: ");
                for(i = 0; i < 4; i ++)
                        printk(KERN_INFO "%c",
                                flags->global_info_struct.codename[i]);
                printk(KERN_INFO "\nCode version: ");
                for(i = 0; i < 4; i ++)
                        printk(KERN_INFO "%c",
                                flags->global_info_struct.codeversion[i]);
                printk(KERN_INFO "\n");


        /* Bug Fix: Mar 6 2000
                 * If we get a corrupted mailbox, it measn that driver 
                 * is out of sync with the firmware. There is no recovery.
                 * If we don't turn off all interrupts for this card
                 * the machine will crash. 
                 */
        printk(KERN_INFO "%s: Critical router failure ...!!!\n", card->devname);
        printk(KERN_INFO "Please contact Sangoma Technologies !\n");
        chdlc_set_intr_mode(card,0);    
        return;
    }

    len  = rxbuf->frame_length;

#if defined(LINUX_2_4) || defined(LINUX_2_1)    
    if (card->tty_opt){

        if (rxbuf->error_flag){    
            goto rx_exit;
        }

        if (len <= CRC_LENGTH){
            goto rx_exit;
        }
        
        if (!card->u.c.async_mode){
            len -= CRC_LENGTH;
        }

        wanpipe_tty_receive(card,addr,len);
        goto rx_exit;
    }
#endif

    dev = card->wandev.dev;

    if (!dev){
        goto rx_exit;
    }

    if (!is_dev_running(dev))
        goto rx_exit;

    chdlc_priv_area = dev->priv;

    
    /* Allocate socket buffer */
    skb = dev_alloc_skb(len);

    if (skb == NULL) {
        printk(KERN_INFO "%s: no socket buffers available!\n",
                    card->devname);
        ++card->wandev.stats.rx_dropped;
        goto rx_exit;
    }

    /* Copy data to the socket buffer */
    if((addr + len) > card->u.c.rx_top + 1) {
        unsigned tmp = card->u.c.rx_top - addr + 1;
        buf = skb_put(skb, tmp);
        sdla_peek(&card->hw, addr, buf, tmp);
        addr = card->u.c.rx_base;
        len -= tmp;
    }
        
    buf = skb_put(skb, len);
    sdla_peek(&card->hw, addr, buf, len);

    skb->protocol = htons(ETH_P_IP);

    card->wandev.stats.rx_packets ++;
#if defined(LINUX_2_1) || defined(LINUX_2_4)
    card->wandev.stats.rx_bytes += skb->len;
#endif
    udp_type = udp_pkt_type( skb, card );

    if(udp_type == UDP_CPIPE_TYPE) {
        if(store_udp_mgmt_pkt(UDP_PKT_FRM_NETWORK,
                         card, skb, dev, chdlc_priv_area)) {
                     flags->interrupt_info_struct.
                        interrupt_permission |= 
                            APP_INT_ON_TIMER; 
        }
#if defined(LINUX_2_1) || defined(LINUX_2_4)
    } else if(card->u.c.usedby == API) {

        api_rx_hdr_t* api_rx_hdr;
               skb_push(skb, sizeof(api_rx_hdr_t));
                api_rx_hdr = (api_rx_hdr_t*)&skb->data[0x00];
        api_rx_hdr->error_flag = rxbuf->error_flag;
             api_rx_hdr->time_stamp = rxbuf->time_stamp;

                skb->protocol = htons(PVC_PROT);
             skb->mac.raw  = skb->data;
        skb->dev      = dev;
                   skb->pkt_type = WAN_PACKET_DATA;

        bh_enqueue(dev, skb);

        if (!test_and_set_bit(0,&chdlc_priv_area->tq_working)){
            wanpipe_queue_tq(&chdlc_priv_area->common.wanpipe_task);
                wanpipe_mark_bh();
        }
#endif
    }else{
        /* FIXME: we should check to see if the received packet is a 
                          multicast packet so that we can increment the multicast 
                          statistic
                          ++ chdlc_priv_area->if_stats.multicast;
        */
                   /* Pass it up the protocol stack */
    
                skb->dev = dev;
                skb->mac.raw  = skb->data;
                netif_rx(skb);
    }

rx_exit:
    /* Release buffer element and calculate a pointer to the next one */
    rxbuf->opp_flag = 0x00;
    card->u.c.rxmb = ++ rxbuf;
    if((void*)rxbuf > card->u.c.rxbuf_last){
        card->u.c.rxmb = card->u.c.rxbuf_base;
    }
}

/*============================================================================
 * Timer interrupt handler.
 * The timer interrupt is used for two purposes:
 *    1) Processing udp calls from 'cpipemon'.
 *    2) Reading board-level statistics for updating the proc file system.
 */
void timer_intr(sdla_t *card)
{
        netdevice_t* dev;
        chdlc_private_area_t* chdlc_priv_area = NULL;
        SHARED_MEMORY_INFO_STRUCT* flags = NULL;

        if ((dev = card->wandev.dev)==NULL){
        flags = card->u.c.flags;
                flags->interrupt_info_struct.interrupt_permission &=
                        ~APP_INT_ON_TIMER;
        return;
    }
    
        chdlc_priv_area = dev->priv;

    if (chdlc_priv_area->timer_int_enabled & TMR_INT_ENABLED_CONFIG) {
        if (!config_chdlc(card)){
            chdlc_priv_area->timer_int_enabled &= ~TMR_INT_ENABLED_CONFIG;
        }
    }

    /* process a udp call if pending */
           if(chdlc_priv_area->timer_int_enabled & TMR_INT_ENABLED_UDP) {
                   process_udp_mgmt_pkt(card, dev,
                       chdlc_priv_area);
        chdlc_priv_area->timer_int_enabled &= ~TMR_INT_ENABLED_UDP;
        }

    /* read the communications statistics if required */
    if(chdlc_priv_area->timer_int_enabled & TMR_INT_ENABLED_UPDATE) {
        update_comms_stats(card, chdlc_priv_area);
                if(!(-- chdlc_priv_area->update_comms_stats)) {
            chdlc_priv_area->timer_int_enabled &= 
                ~TMR_INT_ENABLED_UPDATE;
        }
        }

    /* only disable the timer interrupt if there are no udp or statistic */
    /* updates pending */
        if(!chdlc_priv_area->timer_int_enabled) {
                flags = card->u.c.flags;
                flags->interrupt_info_struct.interrupt_permission &=
                        ~APP_INT_ON_TIMER;
        }
}

/*------------------------------------------------------------------------------
  Miscellaneous Functions
    - set_chdlc_config() used to set configuration options on the board
------------------------------------------------------------------------------*/

static int set_chdlc_config(sdla_t* card)
{
    CHDLC_CONFIGURATION_STRUCT cfg;

    memset(&cfg, 0, sizeof(CHDLC_CONFIGURATION_STRUCT));

    if(card->wandev.clocking){
        cfg.baud_rate = card->wandev.bps;
    }
        
    cfg.line_config_options = (card->wandev.interface == WANOPT_RS232) ?
        INTERFACE_LEVEL_RS232 : INTERFACE_LEVEL_V35;

    cfg.modem_config_options    = 0;
    cfg.modem_status_timer        = 100;

    cfg.CHDLC_protocol_options    = card->u.c.protocol_options;

    if (card->tty_opt){
        cfg.CHDLC_API_options    = DISCARD_RX_ERROR_FRAMES;
    }
    
    cfg.percent_data_buffer_for_Tx  = (card->u.c.receive_only) ? 0 : 50;
    cfg.CHDLC_statistics_options    = (CHDLC_TX_DATA_BYTE_COUNT_STAT |
        CHDLC_RX_DATA_BYTE_COUNT_STAT);
    
    if (card->tty_opt){
        card->wandev.mtu = TTY_CHDLC_MAX_MTU;
    }
    cfg.max_CHDLC_data_field_length    = card->wandev.mtu;
    cfg.transmit_keepalive_timer    = card->u.c.kpalv_tx;
    cfg.receive_keepalive_timer    = card->u.c.kpalv_rx;
    cfg.keepalive_error_tolerance    = card->u.c.kpalv_err;
    cfg.SLARP_request_timer        = card->u.c.slarp_timer;

    if (cfg.SLARP_request_timer) {
        cfg.IP_address        = 0;
        cfg.IP_netmask        = 0;
        
    }else if (card->wandev.dev){
        netdevice_t * dev = card->wandev.dev;
        chdlc_private_area_t *chdlc_priv_area = dev->priv;
        
#if defined(LINUX_2_1) || defined(LINUX_2_4)
                struct in_device *in_dev = dev->ip_ptr;

        if(in_dev != NULL) {
            struct in_ifaddr *ifa = in_dev->ifa_list;

            if (ifa != NULL ) {
                cfg.IP_address    = ntohl(ifa->ifa_local);
                cfg.IP_netmask    = ntohl(ifa->ifa_mask); 
                chdlc_priv_area->IP_address = ntohl(ifa->ifa_local);
                chdlc_priv_area->IP_netmask = ntohl(ifa->ifa_mask); 
            }
        }
#else
                cfg.IP_address          = ntohl(dev->pa_addr);
                cfg.IP_netmask          = ntohl(dev->pa_mask);
        chdlc_priv_area->IP_address = ntohl(dev->pa_addr);
        chdlc_priv_area->IP_netmask = ntohl(dev->pa_mask);
#endif

        /* FIXME: We must re-think this message in next release
        if((cfg.IP_address & 0x000000FF) > 2) {
            printk(KERN_WARNING "\n");
                    printk(KERN_WARNING "  WARNING:%s configured with an\n",
                card->devname);
            printk(KERN_WARNING "  invalid local IP address.\n");
                        printk(KERN_WARNING "  Slarp pragmatics will fail.\n");
                        printk(KERN_WARNING "  IP address should be of the\n");
            printk(KERN_WARNING "  format A.B.C.1 or A.B.C.2.\n");
        }
        */        
    }
    
    return chdlc_configure(card, &cfg);
}


/*-----------------------------------------------------------------------------
   set_asy_config() used to set asynchronous configuration options on the board
------------------------------------------------------------------------------*/

static int set_asy_config(sdla_t* card)
{

        ASY_CONFIGURATION_STRUCT cfg;
     CHDLC_MAILBOX_STRUCT *mailbox = card->mbox;
    int err;

    memset(&cfg, 0, sizeof(ASY_CONFIGURATION_STRUCT));

    if(card->wandev.clocking)
        cfg.baud_rate = card->wandev.bps;

    cfg.line_config_options = (card->wandev.interface == WANOPT_RS232) ?
        INTERFACE_LEVEL_RS232 : INTERFACE_LEVEL_V35;

    cfg.modem_config_options    = 0;
    cfg.asy_API_options         = card->u.c.api_options;
    cfg.asy_protocol_options    = card->u.c.protocol_options;
    cfg.Tx_bits_per_char        = card->u.c.tx_bits_per_char;
    cfg.Rx_bits_per_char        = card->u.c.rx_bits_per_char;
    cfg.stop_bits            = card->u.c.stop_bits;
    cfg.parity            = card->u.c.parity;
    cfg.break_timer            = card->u.c.break_timer;
    cfg.asy_Rx_inter_char_timer    = card->u.c.inter_char_timer; 
    cfg.asy_Rx_complete_length    = card->u.c.rx_complete_length; 
    cfg.XON_char            = card->u.c.xon_char;
    cfg.XOFF_char            = card->u.c.xoff_char;
    cfg.asy_statistics_options    = (CHDLC_TX_DATA_BYTE_COUNT_STAT |
        CHDLC_RX_DATA_BYTE_COUNT_STAT);

    mailbox->buffer_length = sizeof(ASY_CONFIGURATION_STRUCT);
    memcpy(mailbox->data, &cfg, mailbox->buffer_length);
    mailbox->command = SET_ASY_CONFIGURATION;
    err = sdla_exec(mailbox) ? mailbox->return_code : CMD_TIMEOUT;
    if (err != COMMAND_OK) 
        chdlc_error (card, err, mailbox);
    return err;
}

/*============================================================================
 * Enable asynchronous communications.
 */

static int asy_comm_enable (sdla_t* card)
{

    int err;
    CHDLC_MAILBOX_STRUCT* mb = card->mbox;

    mb->buffer_length = 0;
    mb->command = ENABLE_ASY_COMMUNICATIONS;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
    if (err != COMMAND_OK && card->wandev.dev)
        chdlc_error(card, err, mb);
    
    if (!err)
        card->u.c.comm_enabled = 1;

    return err;
}

/*============================================================================
 * Process global exception condition
 */
static int process_global_exception(sdla_t *card)
{
    CHDLC_MAILBOX_STRUCT* mbox = card->mbox;
    int err;

    mbox->buffer_length = 0;
    mbox->command = READ_GLOBAL_EXCEPTION_CONDITION;
    err = sdla_exec(mbox) ? mbox->return_code : CMD_TIMEOUT;

    if(err != CMD_TIMEOUT ){
    
        switch(mbox->return_code) {
         
              case EXCEP_MODEM_STATUS_CHANGE:

            printk(KERN_INFO "%s: Modem status change\n",
                card->devname);

            switch(mbox->data[0] & (DCD_HIGH | CTS_HIGH)) {
                case (DCD_HIGH):
                    printk(KERN_INFO "%s: DCD high, CTS low\n",card->devname);
                    break;
                case (CTS_HIGH):
                                        printk(KERN_INFO "%s: DCD low, CTS high\n",card->devname); 
                    break;
                                case ((DCD_HIGH | CTS_HIGH)):
                                        printk(KERN_INFO "%s: DCD high, CTS high\n",card->devname);
                                        break;
                default:
                                        printk(KERN_INFO "%s: DCD low, CTS low\n",card->devname);
                                        break;
            }
            break;

                case EXCEP_TRC_DISABLED:
                        printk(KERN_INFO "%s: Line trace disabled\n",
                card->devname);
                        break;

        case EXCEP_IRQ_TIMEOUT:
            printk(KERN_INFO "%s: IRQ timeout occurred\n",
                card->devname); 
            break;

        case 0x17:
            if (card->tty_opt){
                if (card->tty && card->tty_open){ 
                    printk(KERN_INFO 
                        "%s: Modem Hangup Exception: Hanging Up!\n",
                        card->devname);
                    tty_hangup(card->tty);
                }
                break;
            }

            /* If TTY is not used just drop throught */
            
                default:
                        printk(KERN_INFO "%s: Global exception %x\n",
                card->devname, mbox->return_code);
                        break;
                }
    }
    return 0;
}


/*============================================================================
 * Process chdlc exception condition
 */
static int process_chdlc_exception(sdla_t *card)
{
    CHDLC_MAILBOX_STRUCT* mb = card->mbox;
    int err;

    mb->buffer_length = 0;
    mb->command = READ_CHDLC_EXCEPTION_CONDITION;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
    if(err != CMD_TIMEOUT) {
    
        switch (err) {

        case EXCEP_LINK_ACTIVE:
            port_set_state(card, WAN_CONNECTED);
            trigger_chdlc_poll(card->wandev.dev);
            break;

        case EXCEP_LINK_INACTIVE_MODEM:
            port_set_state(card, WAN_DISCONNECTED);
            unconfigure_ip(card);
            trigger_chdlc_poll(card->wandev.dev);
            break;

        case EXCEP_LINK_INACTIVE_KPALV:
            port_set_state(card, WAN_DISCONNECTED);
            printk(KERN_INFO "%s: Keepalive timer expired.\n",
                         card->devname);
            unconfigure_ip(card);
            trigger_chdlc_poll(card->wandev.dev);
            break;

        case EXCEP_IP_ADDRESS_DISCOVERED:
            if (configure_ip(card)) 
                return -1;
            break;

        case EXCEP_LOOPBACK_CONDITION:
            printk(KERN_INFO "%s: Loopback Condition Detected.\n",
                        card->devname);
            break;

        case NO_CHDLC_EXCEP_COND_TO_REPORT:
            printk(KERN_INFO "%s: No exceptions reported.\n",
                        card->devname);
            break;
        }

    }
    return 0;
}


/*============================================================================
 * Configure IP from SLARP negotiation
 * This adds dynamic routes when SLARP has provided valid addresses
 */

static int configure_ip (sdla_t* card)
{
    netdevice_t *dev = card->wandev.dev;
        chdlc_private_area_t *chdlc_priv_area;
        char err;

    if (!dev)
        return 0;

    chdlc_priv_area = dev->priv;
    
    
        /* set to discover */
        if(card->u.c.slarp_timer != 0x00) {
        CHDLC_MAILBOX_STRUCT* mb = card->mbox;
        CHDLC_CONFIGURATION_STRUCT *cfg;

             mb->buffer_length = 0;
        mb->command = READ_CHDLC_CONFIGURATION;
        err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
    
        if(err != COMMAND_OK) {
            chdlc_error(card,err,mb);
            return -1;
        }

        cfg = (CHDLC_CONFIGURATION_STRUCT *)mb->data;
                chdlc_priv_area->IP_address = cfg->IP_address;
                chdlc_priv_area->IP_netmask = cfg->IP_netmask;

        /* Set flag to add route */
        chdlc_priv_area->route_status = ADD_ROUTE;

        /* The idea here is to add the route in the poll routine.
           This way, we aren't in interrupt context when adding routes */
        trigger_chdlc_poll(dev);
        }

    return 0;
}


/*============================================================================
 * Un-Configure IP negotiated by SLARP
 * This removes dynamic routes when the link becomes inactive.
 */

static int unconfigure_ip (sdla_t* card)
{
    netdevice_t *dev = card->wandev.dev;
    chdlc_private_area_t *chdlc_priv_area;

    if (!dev)
        return 0;

    chdlc_priv_area= dev->priv;
    
    if (chdlc_priv_area->route_status == ROUTE_ADDED) {

        /* Note: If this function is called, the 
                 * port state has been DISCONNECTED.  This state
                 * change will trigger a poll_disconnected 
                 * function, that will check for this condition. 
         */
        chdlc_priv_area->route_status = REMOVE_ROUTE;

    }
    return 0;
}

/*============================================================================
 * Routine to add/remove routes 
 * Called like a polling routine when Routes are flagged to be added/removed.
 */

static void process_route (sdla_t *card)
{
        netdevice_t *dev = card->wandev.dev;
        unsigned char port_num;
        chdlc_private_area_t *chdlc_priv_area = NULL;
    u32 local_IP_addr = 0;
    u32 remote_IP_addr = 0;
    u32 IP_netmask, IP_addr;
        int err = 0;
#if defined(LINUX_2_1) || defined(LINUX_2_4)
    struct in_device *in_dev;
    mm_segment_t fs;
    struct ifreq if_info;
        struct sockaddr_in *if_data1, *if_data2;
#else
    unsigned long fs = 0;
        struct rtentry route;
#endif
    
        chdlc_priv_area = dev->priv;
        port_num = card->u.c.comm_port;

    /* Bug Fix Mar 16 2000
     * AND the IP address to the Mask before checking
         * the last two bits. */

    if((chdlc_priv_area->route_status == ADD_ROUTE) &&
        ((chdlc_priv_area->IP_address & ~chdlc_priv_area->IP_netmask) > 2)) {

        printk(KERN_INFO "%s: Dynamic route failure.\n",card->devname);

                if(card->u.c.slarp_timer) {

            printk(KERN_INFO "%s: Bad IP address %s received\n",
                card->devname,
                in_ntoa(ntohl(chdlc_priv_area->IP_address)));
                        printk(KERN_INFO "%s: from remote station.\n",
                card->devname);

                }else{ 

                        printk(KERN_INFO "%s: Bad IP address %s issued\n",
                card->devname,
                in_ntoa(ntohl(chdlc_priv_area->IP_address)));
                        printk(KERN_INFO "%s: to remote station. Local\n",
                card->devname);
            printk(KERN_INFO "%s: IP address must be A.B.C.1\n",
                card->devname);
            printk(KERN_INFO "%s: or A.B.C.2.\n",card->devname);
        }

        /* remove the route due to the IP address error condition */
        chdlc_priv_area->route_status = REMOVE_ROUTE;
        err = 1;
       }

    /* If we are removing a route with bad IP addressing, then use the */
    /* locally configured IP addresses */
        if((chdlc_priv_area->route_status == REMOVE_ROUTE) && err) {

             /* do not remove a bad route that has already been removed */
            if(chdlc_priv_area->route_removed) {
                    return;
            }

#if defined(LINUX_2_1) || defined(LINUX_2_4)
                in_dev = dev->ip_ptr;

                if(in_dev != NULL) {
                        struct in_ifaddr *ifa = in_dev->ifa_list;
                        if (ifa != NULL ) {
                                local_IP_addr = ifa->ifa_local;
                                IP_netmask  = ifa->ifa_mask;
                        }
                }
#else
                local_IP_addr = dev->pa_addr;
                remote_IP_addr = dev->pa_dstaddr;
                IP_netmask = dev->pa_mask;
#endif
    }else{ 
               /* According to Cisco HDLC, if the point-to-point address is
           A.B.C.1, then we are the opposite (A.B.C.2), and vice-versa.
        */
        IP_netmask = ntohl(chdlc_priv_area->IP_netmask);
            remote_IP_addr = ntohl(chdlc_priv_area->IP_address);
    

        /* If Netmask is 255.255.255.255 the local address
                 * calculation will fail. Default it back to 255.255.255.0 */
        if (IP_netmask == 0xffffffff)
            IP_netmask &= 0x00ffffff;

        /* Bug Fix Mar 16 2000
         * AND the Remote IP address with IP netmask, instead
                 * of static netmask of 255.255.255.0 */
            local_IP_addr = (remote_IP_addr & IP_netmask) +
                    (~remote_IP_addr & ntohl(0x0003));

            if(!card->u.c.slarp_timer) {
            IP_addr = local_IP_addr;
            local_IP_addr = remote_IP_addr;
            remote_IP_addr = IP_addr;
               }
    }

        fs = get_fs();                  /* Save file system  */
        set_fs(get_ds());               /* Get user space block */

#if defined(LINUX_2_1) || defined(LINUX_2_4)
        /* Setup a structure for adding/removing routes */
        memset(&if_info, 0, sizeof(if_info));
        strcpy(if_info.ifr_name, dev->name);

#else
    /* Setup a structure for adding/removing routes */
    dev->pa_mask = IP_netmask;
    dev->pa_dstaddr = remote_IP_addr;
    dev->pa_addr = local_IP_addr;

    memset(&route, 0, sizeof(route));
    route.rt_dev = dev->name;
    route.rt_flags = 0;
    ((struct sockaddr_in *)&(route.rt_dst))->sin_addr.s_addr =
            dev->pa_dstaddr;
    ((struct sockaddr_in *)&(route.rt_dst))->sin_family = AF_INET;
    ((struct sockaddr_in *)&(route.rt_genmask))->sin_addr.s_addr =
            0xFFFFFFFF;
        ((struct sockaddr_in *)&(route.rt_genmask))->sin_family =
            AF_INET;
#endif

    switch (chdlc_priv_area->route_status) {

    case ADD_ROUTE:

        if(!card->u.c.slarp_timer) {
#if defined(LINUX_2_1) || defined(LINUX_2_4)
            if_data2 = (struct sockaddr_in *)&if_info.ifr_dstaddr;
            if_data2->sin_addr.s_addr = remote_IP_addr;
            if_data2->sin_family = AF_INET;
            err = devinet_ioctl(SIOCSIFDSTADDR, &if_info);
#else
                        err = ip_rt_new(&route);
#endif
        } else { 
#if defined(LINUX_2_1) || defined(LINUX_2_4)
            if_data1 = (struct sockaddr_in *)&if_info.ifr_addr;
            if_data1->sin_addr.s_addr = local_IP_addr;
            if_data1->sin_family = AF_INET;
            if(!(err = devinet_ioctl(SIOCSIFADDR, &if_info))){
                if_data2 = (struct sockaddr_in *)&if_info.ifr_dstaddr;
                if_data2->sin_addr.s_addr = remote_IP_addr;
                if_data2->sin_family = AF_INET;
                err = devinet_ioctl(SIOCSIFDSTADDR, &if_info);
            }
#else
                       err = ip_rt_new(&route);
#endif
        }

               if(err) {
            printk(KERN_INFO "%s: Add route %s failed (%d)\n", 
                card->devname, in_ntoa(remote_IP_addr), err);
        } else {
            ((chdlc_private_area_t *)dev->priv)->route_status = ROUTE_ADDED;
            printk(KERN_INFO "%s: Dynamic route added.\n",
                card->devname);
            printk(KERN_INFO "%s:    Local IP addr : %s\n",
                card->devname, in_ntoa(local_IP_addr));
            printk(KERN_INFO "%s:    Remote IP addr: %s\n",
                card->devname, in_ntoa(remote_IP_addr));
            chdlc_priv_area->route_removed = 0;
        }
        break;


    case REMOVE_ROUTE:
    
#if defined(LINUX_2_1) || defined(LINUX_2_4)
        /* Change the local ip address of the interface to 0.
         * This will also delete the destination route.
         */
        if(!card->u.c.slarp_timer) {
            if_data2 = (struct sockaddr_in *)&if_info.ifr_dstaddr;
            if_data2->sin_addr.s_addr = 0;
            if_data2->sin_family = AF_INET;
            err = devinet_ioctl(SIOCSIFDSTADDR, &if_info);
        } else {
            if_data1 = (struct sockaddr_in *)&if_info.ifr_addr;
            if_data1->sin_addr.s_addr = 0;
            if_data1->sin_family = AF_INET;
            err = devinet_ioctl(SIOCSIFADDR,&if_info);
        
        }
#else
        /* set the point-to-point IP address to 0.0.0.0 */
        dev->pa_dstaddr = 0; 
        err = ip_rt_kill(&route);
#endif
        if(err) {
            printk(KERN_INFO
                "%s: Remove route %s failed, (err %d)\n",
                    card->devname, in_ntoa(remote_IP_addr),
                    err);
        } else {
            ((chdlc_private_area_t *)dev->priv)->route_status =
                NO_ROUTE;
                        printk(KERN_INFO "%s: Dynamic route removed: %s\n",
                                        card->devname, in_ntoa(local_IP_addr)); 
            chdlc_priv_area->route_removed = 1;
        }
        break;
    }

        set_fs(fs);                     /* Restore file system */

}


/*=============================================================================
 * Store a UDP management packet for later processing.
 */

static int store_udp_mgmt_pkt(char udp_pkt_src, sdla_t* card,
                                struct sk_buff *skb, netdevice_t* dev,
                                chdlc_private_area_t* chdlc_priv_area )
{
    int udp_pkt_stored = 0;

    if(!chdlc_priv_area->udp_pkt_lgth &&
      (skb->len <= MAX_LGTH_UDP_MGNT_PKT)) {
            chdlc_priv_area->udp_pkt_lgth = skb->len;
        chdlc_priv_area->udp_pkt_src = udp_pkt_src;
               memcpy(chdlc_priv_area->udp_pkt_data, skb->data, skb->len);
        chdlc_priv_area->timer_int_enabled = TMR_INT_ENABLED_UDP;
        udp_pkt_stored = 1;
    }

    if(udp_pkt_src == UDP_PKT_FRM_STACK){
        wan_dev_kfree_skb(skb, FREE_WRITE);
    }else{
                wan_dev_kfree_skb(skb, FREE_READ);
    }
        
    return(udp_pkt_stored);
}


/*=============================================================================
 * Process UDP management packet.
 */

static int process_udp_mgmt_pkt(sdla_t* card, netdevice_t* dev,
                chdlc_private_area_t* chdlc_priv_area ) 
{
    unsigned char *buf;
    unsigned int frames, len;
    struct sk_buff *new_skb;
    unsigned short buffer_length, real_len;
    unsigned long data_ptr;
    unsigned data_length;
    int udp_mgmt_req_valid = 1;
    CHDLC_MAILBOX_STRUCT *mb = card->mbox;
    SHARED_MEMORY_INFO_STRUCT *flags = card->u.c.flags;
    chdlc_udp_pkt_t *chdlc_udp_pkt;
    struct timeval tv;
    int err;
    char ut_char;

    chdlc_udp_pkt = (chdlc_udp_pkt_t *) chdlc_priv_area->udp_pkt_data;

    if(chdlc_priv_area->udp_pkt_src == UDP_PKT_FRM_NETWORK){

        /* Only these commands are support for remote debugging.
         * All others are not */
        switch(chdlc_udp_pkt->cblock.command) {

            case READ_GLOBAL_STATISTICS:
            case READ_MODEM_STATUS:  
            case READ_CHDLC_LINK_STATUS:
            case CPIPE_ROUTER_UP_TIME:
            case READ_COMMS_ERROR_STATS:
            case READ_CHDLC_OPERATIONAL_STATS:

            /* These two commands are executed for
             * each request */
            case READ_CHDLC_CONFIGURATION:
            case READ_CHDLC_CODE_VERSION:
                udp_mgmt_req_valid = 1;
                break;
            default:
                udp_mgmt_req_valid = 0;
                break;
        } 
    }
    
      if(!udp_mgmt_req_valid) {

        /* set length to 0 */
        chdlc_udp_pkt->cblock.buffer_length = 0;

            /* set return code */
        chdlc_udp_pkt->cblock.return_code = 0xCD;

        if (net_ratelimit()){    
            printk(KERN_INFO 
            "%s: Warning, Illegal UDP command attempted from network: %x\n",
            card->devname,chdlc_udp_pkt->cblock.command);
        }

       } else {
           unsigned long trace_status_cfg_addr = 0;
        TRACE_STATUS_EL_CFG_STRUCT trace_cfg_struct;
        TRACE_STATUS_ELEMENT_STRUCT trace_element_struct;

        switch(chdlc_udp_pkt->cblock.command) {

        case CPIPE_ENABLE_TRACING:
             if (!chdlc_priv_area->TracingEnabled) {

            /* OPERATE_DATALINE_MONITOR */

            mb->buffer_length = sizeof(LINE_TRACE_CONFIG_STRUCT);
            mb->command = SET_TRACE_CONFIGURATION;

                ((LINE_TRACE_CONFIG_STRUCT *)mb->data)->
                trace_config = TRACE_ACTIVE;
            /* Trace delay mode is not used because it slows
               down transfer and results in a standoff situation
               when there is a lot of data */

            /* Configure the Trace based on user inputs */
            ((LINE_TRACE_CONFIG_STRUCT *)mb->data)->trace_config |= 
                    chdlc_udp_pkt->data[0];

            ((LINE_TRACE_CONFIG_STRUCT *)mb->data)->
               trace_deactivation_timer = 4000;


            err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
            if (err != COMMAND_OK) {
                chdlc_error(card,err,mb);
                card->TracingEnabled = 0;
                chdlc_udp_pkt->cblock.return_code = err;
                mb->buffer_length = 0;
                break;
                } 

            /* Get the base address of the trace element list */
            mb->buffer_length = 0;
            mb->command = READ_TRACE_CONFIGURATION;
            err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;

            if (err != COMMAND_OK) {
                chdlc_error(card,err,mb);
                chdlc_priv_area->TracingEnabled = 0;
                chdlc_udp_pkt->cblock.return_code = err;
                mb->buffer_length = 0;
                break;
                }     

               trace_status_cfg_addr =((LINE_TRACE_CONFIG_STRUCT *)
                mb->data) -> ptr_trace_stat_el_cfg_struct;

            sdla_peek(&card->hw, trace_status_cfg_addr,
                 &trace_cfg_struct, sizeof(trace_cfg_struct));
            
            chdlc_priv_area->start_trace_addr = trace_cfg_struct.
                base_addr_trace_status_elements;

            chdlc_priv_area->number_trace_elements = 
                    trace_cfg_struct.number_trace_status_elements;

            chdlc_priv_area->end_trace_addr = (unsigned long)
                    ((TRACE_STATUS_ELEMENT_STRUCT *)
                     chdlc_priv_area->start_trace_addr + 
                     (chdlc_priv_area->number_trace_elements - 1));

            chdlc_priv_area->base_addr_trace_buffer = 
                    trace_cfg_struct.base_addr_trace_buffer;

            chdlc_priv_area->end_addr_trace_buffer = 
                    trace_cfg_struct.end_addr_trace_buffer;

                chdlc_priv_area->curr_trace_addr = 
                    trace_cfg_struct.next_trace_element_to_use;

                chdlc_priv_area->available_buffer_space = 2000 - 
                                  sizeof(ip_pkt_t) -
                                  sizeof(udp_pkt_t) -
                                        sizeof(wp_mgmt_t) -
                                  sizeof(cblock_t) -
                                      sizeof(trace_info_t);    
                    }
             chdlc_udp_pkt->cblock.return_code = COMMAND_OK;
             mb->buffer_length = 0;
                    chdlc_priv_area->TracingEnabled = 1;
                    break;
       

        case CPIPE_DISABLE_TRACING:
             if (chdlc_priv_area->TracingEnabled) {

            /* OPERATE_DATALINE_MONITOR */
            mb->buffer_length = sizeof(LINE_TRACE_CONFIG_STRUCT);
            mb->command = SET_TRACE_CONFIGURATION;
                ((LINE_TRACE_CONFIG_STRUCT *)mb->data)->
                trace_config = TRACE_INACTIVE;
            err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
             }        

             chdlc_priv_area->TracingEnabled = 0;
             chdlc_udp_pkt->cblock.return_code = COMMAND_OK;
             mb->buffer_length = 0;
             break;
       

        case CPIPE_GET_TRACE_INFO:

             if (!chdlc_priv_area->TracingEnabled) {
            chdlc_udp_pkt->cblock.return_code = 1;
            mb->buffer_length = 0;
            break;
             }

               chdlc_udp_pkt->trace_info.ismoredata = 0x00;
             buffer_length = 0;    /* offset of packet already occupied */

             for (frames=0; frames < chdlc_priv_area->number_trace_elements; frames++){

            trace_pkt_t *trace_pkt = (trace_pkt_t *)
                &chdlc_udp_pkt->data[buffer_length];

            sdla_peek(&card->hw, chdlc_priv_area->curr_trace_addr,
                     (unsigned char *)&trace_element_struct,
                     sizeof(TRACE_STATUS_ELEMENT_STRUCT));

                 if (trace_element_struct.opp_flag == 0x00) {
                 break;
            }

            /* get pointer to real data */
            data_ptr = trace_element_struct.ptr_data_bfr;

            /* See if there is actual data on the trace buffer */
            if (data_ptr){
                data_length = trace_element_struct.trace_length;
            }else{
                data_length = 0;
                chdlc_udp_pkt->trace_info.ismoredata = 0x01;
            }
    
               if( (chdlc_priv_area->available_buffer_space - buffer_length)
                < ( sizeof(trace_pkt_t) + data_length) ) {

                            /* indicate there are more frames on board & exit */
                chdlc_udp_pkt->trace_info.ismoredata = 0x01;
                                   break;
                         }

            trace_pkt->status = trace_element_struct.trace_type;

            trace_pkt->time_stamp =
                trace_element_struct.trace_time_stamp;

            trace_pkt->real_length =
                trace_element_struct.trace_length;

            /* see if we can fit the frame into the user buffer */
            real_len = trace_pkt->real_length;

            if (data_ptr == 0) {
                     trace_pkt->data_avail = 0x00;
            } else {
                unsigned tmp = 0;

                /* get the data from circular buffer
                    must check for end of buffer */
                    trace_pkt->data_avail = 0x01;

                if ((data_ptr + real_len) >
                         chdlc_priv_area->end_addr_trace_buffer + 1){

                        tmp = chdlc_priv_area->end_addr_trace_buffer - data_ptr + 1;
                        sdla_peek(&card->hw, data_ptr,
                                 trace_pkt->data,tmp);
                        data_ptr = chdlc_priv_area->base_addr_trace_buffer;
                }
    
                    sdla_peek(&card->hw, data_ptr,
                      &trace_pkt->data[tmp], real_len - tmp);
            }    

            /* zero the opp flag to show we got the frame */
            ut_char = 0x00;
            sdla_poke(&card->hw, chdlc_priv_area->curr_trace_addr, &ut_char, 1);

                   /* now move onto the next frame */
                   chdlc_priv_area->curr_trace_addr += sizeof(TRACE_STATUS_ELEMENT_STRUCT);

                   /* check if we went over the last address */
            if ( chdlc_priv_area->curr_trace_addr > chdlc_priv_area->end_trace_addr ) {
                chdlc_priv_area->curr_trace_addr = chdlc_priv_area->start_trace_addr;
                   }

                    if(trace_pkt->data_avail == 0x01) {
                buffer_length += real_len - 1;
            }
     
                       /* for the header */
                    buffer_length += sizeof(trace_pkt_t);

             }  /* For Loop */

             if (frames == chdlc_priv_area->number_trace_elements){
            chdlc_udp_pkt->trace_info.ismoredata = 0x01;
                 }
              chdlc_udp_pkt->trace_info.num_frames = frames;
         
                 mb->buffer_length = buffer_length;
             chdlc_udp_pkt->cblock.buffer_length = buffer_length; 
         
             chdlc_udp_pkt->cblock.return_code = COMMAND_OK; 
             
             break;


        case CPIPE_FT1_READ_STATUS:
            ((unsigned char *)chdlc_udp_pkt->data )[0] =
                flags->FT1_info_struct.parallel_port_A_input;

            ((unsigned char *)chdlc_udp_pkt->data )[1] =
                flags->FT1_info_struct.parallel_port_B_input;
                
            chdlc_udp_pkt->cblock.return_code = COMMAND_OK;
            chdlc_udp_pkt->cblock.buffer_length = 2;
            mb->buffer_length = 2;
            break;

        case CPIPE_ROUTER_UP_TIME:
            do_gettimeofday( &tv );
            chdlc_priv_area->router_up_time = tv.tv_sec - 
                    chdlc_priv_area->router_start_time;
            *(unsigned long *)&chdlc_udp_pkt->data = 
                    chdlc_priv_area->router_up_time;    
            mb->buffer_length = sizeof(unsigned long);
            chdlc_udp_pkt->cblock.buffer_length = sizeof(unsigned long);
            chdlc_udp_pkt->cblock.return_code = COMMAND_OK;
            break;

           case FT1_MONITOR_STATUS_CTRL:
            /* Enable FT1 MONITOR STATUS */
                if ((chdlc_udp_pkt->data[0] & ENABLE_READ_FT1_STATUS) ||  
                (chdlc_udp_pkt->data[0] & ENABLE_READ_FT1_OP_STATS)) {
            
                     if( rCount++ != 0 ) {
                    chdlc_udp_pkt->cblock.
                    return_code = COMMAND_OK;
                    mb->buffer_length = 1;
                      break;
                         }
                  }

                  /* Disable FT1 MONITOR STATUS */
                  if( chdlc_udp_pkt->data[0] == 0) {

                              if( --rCount != 0) {
                      chdlc_udp_pkt->cblock.
                    return_code = COMMAND_OK;
                    mb->buffer_length = 1;
                      break;
                            } 
                  }     
            goto dflt_1;

        default:
dflt_1:
            /* it's a board command */
            mb->command = chdlc_udp_pkt->cblock.command;
            mb->buffer_length = chdlc_udp_pkt->cblock.buffer_length;
            if (mb->buffer_length) {
                memcpy(&mb->data, (unsigned char *) chdlc_udp_pkt->
                            data, mb->buffer_length);
                  } 
            /* run the command on the board */
            err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
            if (err != COMMAND_OK) {
                break;
            }

            /* copy the result back to our buffer */
                 memcpy(&chdlc_udp_pkt->cblock, mb, sizeof(cblock_t)); 
            
            if (mb->buffer_length) {
                     memcpy(&chdlc_udp_pkt->data, &mb->data, 
                                mb->buffer_length); 
                  }

        } /* end of switch */
         } /* end of else */

         /* Fill UDP TTL */
    chdlc_udp_pkt->ip_pkt.ttl = card->wandev.ttl; 

         len = reply_udp(chdlc_priv_area->udp_pkt_data, mb->buffer_length);
    

         if(chdlc_priv_area->udp_pkt_src == UDP_PKT_FRM_NETWORK){

        /* Must check if we interrupted if_send() routine. The
         * tx buffers might be used. If so drop the packet */
           if (!test_bit(SEND_CRIT,&card->wandev.critical)) {
        
            if(!chdlc_send(card, chdlc_priv_area->udp_pkt_data, len)) {
                ++ card->wandev.stats.tx_packets;
#if defined(LINUX_2_1) || defined(LINUX_2_4)
                card->wandev.stats.tx_bytes += len;
#endif
            }
        }
    } else {    
    
        /* Pass it up the stack
               Allocate socket buffer */
        if ((new_skb = dev_alloc_skb(len)) != NULL) {
            /* copy data into new_skb */

                 buf = skb_put(new_skb, len);
                  memcpy(buf, chdlc_priv_area->udp_pkt_data, len);

                    /* Decapsulate pkt and pass it up the protocol stack */
                new_skb->protocol = htons(ETH_P_IP);
                    new_skb->dev = dev;
                new_skb->mac.raw  = new_skb->data;
    
            netif_rx(new_skb);
        } else {
            
            printk(KERN_INFO "%s: no socket buffers available!\n",
                    card->devname);
          }
        }
 
    chdlc_priv_area->udp_pkt_lgth = 0;
     
    return 0;
}

/*============================================================================
 * Initialize Receive and Transmit Buffers.
 */

static void init_chdlc_tx_rx_buff( sdla_t* card)
{
    CHDLC_MAILBOX_STRUCT* mb = card->mbox;
    CHDLC_TX_STATUS_EL_CFG_STRUCT *tx_config;
    CHDLC_RX_STATUS_EL_CFG_STRUCT *rx_config;
    char err;
    
    mb->buffer_length = 0;
    mb->command = READ_CHDLC_CONFIGURATION;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;

    if(err != COMMAND_OK) {
        if (card->wandev.dev){
            chdlc_error(card,err,mb);
        }
        return;
    }

    if(card->hw.type == SDLA_S514) {
        tx_config = (CHDLC_TX_STATUS_EL_CFG_STRUCT *)(card->hw.dpmbase +
                (((CHDLC_CONFIGURATION_STRUCT *)mb->data)->
                            ptr_CHDLC_Tx_stat_el_cfg_struct));
            rx_config = (CHDLC_RX_STATUS_EL_CFG_STRUCT *)(card->hw.dpmbase +
                (((CHDLC_CONFIGURATION_STRUCT *)mb->data)->
                            ptr_CHDLC_Rx_stat_el_cfg_struct));

               /* Setup Head and Tails for buffers */
            card->u.c.txbuf_base = (void *)(card->hw.dpmbase +
                tx_config->base_addr_Tx_status_elements);
            card->u.c.txbuf_last = 
        (CHDLC_DATA_TX_STATUS_EL_STRUCT *)  
                card->u.c.txbuf_base +
        (tx_config->number_Tx_status_elements - 1);

            card->u.c.rxbuf_base = (void *)(card->hw.dpmbase +
                rx_config->base_addr_Rx_status_elements);
            card->u.c.rxbuf_last =
        (CHDLC_DATA_RX_STATUS_EL_STRUCT *)
                card->u.c.rxbuf_base +
        (rx_config->number_Rx_status_elements - 1);

         /* Set up next pointer to be used */
            card->u.c.txbuf = (void *)(card->hw.dpmbase +
                tx_config->next_Tx_status_element_to_use);
            card->u.c.rxmb = (void *)(card->hw.dpmbase +
                rx_config->next_Rx_status_element_to_use);
    }
        else {
                tx_config = (CHDLC_TX_STATUS_EL_CFG_STRUCT *)(card->hw.dpmbase +
            (((CHDLC_CONFIGURATION_STRUCT *)mb->data)->
            ptr_CHDLC_Tx_stat_el_cfg_struct % SDLA_WINDOWSIZE));

                rx_config = (CHDLC_RX_STATUS_EL_CFG_STRUCT *)(card->hw.dpmbase +
            (((CHDLC_CONFIGURATION_STRUCT *)mb->data)->
            ptr_CHDLC_Rx_stat_el_cfg_struct % SDLA_WINDOWSIZE));

                /* Setup Head and Tails for buffers */
                card->u.c.txbuf_base = (void *)(card->hw.dpmbase +
        (tx_config->base_addr_Tx_status_elements % SDLA_WINDOWSIZE));
                card->u.c.txbuf_last =
        (CHDLC_DATA_TX_STATUS_EL_STRUCT *)card->u.c.txbuf_base
        + (tx_config->number_Tx_status_elements - 1);
                card->u.c.rxbuf_base = (void *)(card->hw.dpmbase +
        (rx_config->base_addr_Rx_status_elements % SDLA_WINDOWSIZE));
                card->u.c.rxbuf_last = 
        (CHDLC_DATA_RX_STATUS_EL_STRUCT *)card->u.c.rxbuf_base
        + (rx_config->number_Rx_status_elements - 1);

                 /* Set up next pointer to be used */
                card->u.c.txbuf = (void *)(card->hw.dpmbase +
        (tx_config->next_Tx_status_element_to_use % SDLA_WINDOWSIZE));
                card->u.c.rxmb = (void *)(card->hw.dpmbase +
        (rx_config->next_Rx_status_element_to_use % SDLA_WINDOWSIZE));
        }

        /* Setup Actual Buffer Start and end addresses */
        card->u.c.rx_base = rx_config->base_addr_Rx_buffer;
        card->u.c.rx_top  = rx_config->end_addr_Rx_buffer;

}

/*=============================================================================
 * Perform Interrupt Test by running READ_CHDLC_CODE_VERSION command MAX_INTR
 * _TEST_COUNTER times.
 */
static int intr_test( sdla_t* card)
{
    CHDLC_MAILBOX_STRUCT* mb = card->mbox;
    int err,i;

    Intr_test_counter = 0;
    
    err = chdlc_set_intr_mode(card, APP_INT_ON_COMMAND_COMPLETE);

    if (err == CMD_OK) { 
        for (i = 0; i < MAX_INTR_TEST_COUNTER; i ++) {    
            mb->buffer_length  = 0;
            mb->command = READ_CHDLC_CODE_VERSION;
            err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
            if (err != CMD_OK) 
                chdlc_error(card, err, mb);
        }
    }
    else {
        return err;
    }

    err = chdlc_set_intr_mode(card, 0);

    if (err != CMD_OK)
        return err;

    return 0;
}

/*==============================================================================
 * Determine what type of UDP call it is. CPIPEAB ?
 */
static int udp_pkt_type(struct sk_buff *skb, sdla_t* card)
{
     chdlc_udp_pkt_t *chdlc_udp_pkt = (chdlc_udp_pkt_t *)skb->data;

#ifdef _WAN_UDP_DEBUG
        printk(KERN_INFO "SIG %s = %s\n\
                  UPP %x = %x\n\
                  PRT %x = %x\n\
                  REQ %i = %i\n\
                  36 th = %x 37th = %x\n",
                  chdlc_udp_pkt->wp_mgmt.signature,
                  UDPMGMT_SIGNATURE,
                  chdlc_udp_pkt->udp_pkt.udp_dst_port,
                  ntohs(card->wandev.udp_port),
                  chdlc_udp_pkt->ip_pkt.protocol,
                  UDPMGMT_UDP_PROTOCOL,
                  chdlc_udp_pkt->wp_mgmt.request_reply,
                  UDPMGMT_REQUEST,
                  skb->data[36], skb->data[37]);
#endif    
        
    if (!strncmp(chdlc_udp_pkt->wp_mgmt.signature,UDPMGMT_SIGNATURE,8) &&
       (chdlc_udp_pkt->udp_pkt.udp_dst_port == ntohs(card->wandev.udp_port)) &&
       (chdlc_udp_pkt->ip_pkt.protocol == UDPMGMT_UDP_PROTOCOL) &&
       (chdlc_udp_pkt->wp_mgmt.request_reply == UDPMGMT_REQUEST)) {

        return UDP_CPIPE_TYPE;

    }else{ 
        return UDP_INVALID_TYPE;
    }
}

/*============================================================================
 * Set PORT state.
 */
static void port_set_state (sdla_t *card, int state)
{
        if (card->u.c.state != state)
        {
                switch (state)
                {
                case WAN_CONNECTED:
                        printk (KERN_INFO "%s: Link connected!\n",
                                card->devname);
                          break;

                case WAN_CONNECTING:
                        printk (KERN_INFO "%s: Link connecting...\n",
                                card->devname);
                        break;

                case WAN_DISCONNECTED:
                        printk (KERN_INFO "%s: Link disconnected!\n",
                                card->devname);
                        break;
                }

                card->wandev.state = card->u.c.state = state;
        if (card->wandev.dev){
            netdevice_t *dev = card->wandev.dev;
            chdlc_private_area_t *chdlc_priv_area = dev->priv;
            chdlc_priv_area->common.state = state;
        }
        }
}

/*===========================================================================
 * config_chdlc
 *
 *    Configure the chdlc protocol and enable communications.        
 *
 *       The if_open() function binds this function to the poll routine.
 *      Therefore, this function will run every time the chdlc interface
 *      is brought up. We cannot run this function from the if_open 
 *      because if_open does not have access to the remote IP address.
 *      
 *    If the communications are not enabled, proceed to configure
 *      the card and enable communications.
 *
 *      If the communications are enabled, it means that the interface
 *      was shutdown by ether the user or driver. In this case, we 
 *      have to check that the IP addresses have not changed.  If
 *      the IP addresses have changed, we have to reconfigure the firmware
 *      and update the changed IP addresses.  Otherwise, just exit.
 *
 */

static int config_chdlc (sdla_t *card)
{
    netdevice_t *dev = card->wandev.dev;
    chdlc_private_area_t *chdlc_priv_area = dev->priv;
    SHARED_MEMORY_INFO_STRUCT *flags = card->u.c.flags;

    if (card->u.c.comm_enabled){

        /* Jun 20. 2000: NC
         * IP addresses are not used in the API mode */
        
        if ((chdlc_priv_area->ip_local_tmp != chdlc_priv_area->ip_local ||
             chdlc_priv_area->ip_remote_tmp != chdlc_priv_area->ip_remote) && 
             card->u.c.usedby == WANPIPE) {
            
            /* The IP addersses have changed, we must
                         * stop the communications and reconfigure
                         * the card. Reason: the firmware must know
                         * the local and remote IP addresses. */
            disable_comm(card);
            port_set_state(card, WAN_DISCONNECTED);
            printk(KERN_INFO 
                "%s: IP addresses changed!\n",
                    card->devname);
            printk(KERN_INFO 
                "%s: Restarting communications ...\n",
                    card->devname);
        }else{ 
            /* IP addresses are the same and the link is up, 
                         * we dont have to do anything here. Therefore, exit */
            return 0;
        }
    }

    chdlc_priv_area->ip_local = chdlc_priv_area->ip_local_tmp;
    chdlc_priv_area->ip_remote = chdlc_priv_area->ip_remote_tmp;


    /* Setup the Board for asynchronous mode */
    if (card->u.c.async_mode){
        
        if (set_asy_config(card)) {
            printk (KERN_INFO "%s: Failed CHDLC Async configuration!\n",
                card->devname);
            return 0;
        }
    }else{
        /* Setup the Board for CHDLC */
        if (set_chdlc_config(card)) {
            printk (KERN_INFO "%s: Failed CHDLC configuration!\n",
                card->devname);
            return 0;
        }
    }

    /* Set interrupt mode and mask */
        if (chdlc_set_intr_mode(card, APP_INT_ON_RX_FRAME |
                        APP_INT_ON_GLOBAL_EXCEP_COND |
                        APP_INT_ON_TX_FRAME |
                        APP_INT_ON_CHDLC_EXCEP_COND | APP_INT_ON_TIMER)){
        printk (KERN_INFO "%s: Failed to set interrupt triggers!\n",
                card->devname);
        return 0;    
        }
    

    /* Mask the Transmit and Timer interrupt */
    flags->interrupt_info_struct.interrupt_permission &= 
        ~(APP_INT_ON_TX_FRAME | APP_INT_ON_TIMER);

    /* In TTY mode, receive interrupt will be enabled during
     * wanpipe_tty_open() operation */
    if (card->tty_opt){
        flags->interrupt_info_struct.interrupt_permission &= ~APP_INT_ON_RX_FRAME;
    }

    /* Enable communications */
     if (card->u.c.async_mode){
        if (asy_comm_enable(card) != 0) {
            printk(KERN_INFO "%s: Failed to enable async commnunication!\n",
                    card->devname);
            flags->interrupt_info_struct.interrupt_permission = 0;
            card->u.c.comm_enabled=0;
            chdlc_set_intr_mode(card,0);
            return 0;
        }
        }else{ 
        if (chdlc_comm_enable(card) != 0) {
            printk(KERN_INFO "%s: Failed to enable chdlc communications!\n",
                    card->devname);
            flags->interrupt_info_struct.interrupt_permission = 0;
            card->u.c.comm_enabled=0;
            chdlc_set_intr_mode(card,0);
            return 0;
        }
    }

    /* Initialize Rx/Tx buffer control fields */
    init_chdlc_tx_rx_buff(card);
    port_set_state(card, WAN_CONNECTING);
    return 0; 
}


/*============================================================
 * chdlc_poll
 *    
 * Rationale:
 *     We cannot manipulate the routing tables, or
 *      ip addresses withing the interrupt. Therefore
 *      we must perform such actons outside an interrupt 
 *      at a later time. 
 *
 * Description:    
 *    CHDLC polling routine, responsible for 
 *         shutting down interfaces upon disconnect
 *         and adding/removing routes. 
 *      
 * Usage:        
 *     This function is executed for each CHDLC  
 *     interface through a tq_schedule bottom half.
 *      
 *      trigger_chdlc_poll() function is used to kick
 *      the chldc_poll routine.  
 */

static void chdlc_poll (netdevice_t *dev)
{
    chdlc_private_area_t *chdlc_priv_area;
    sdla_t *card;
    u8 check_gateway=0;    
    SHARED_MEMORY_INFO_STRUCT* flags;

    
    if (!dev || (chdlc_priv_area=dev->priv) == NULL)
        return;

    card = chdlc_priv_area->card;
    flags = card->u.c.flags;
    
    /* (Re)Configuraiton is in progress, stop what you are 
     * doing and get out */
    if (test_bit(PERI_CRIT,&card->wandev.critical)){
        clear_bit(POLL_CRIT,&card->wandev.critical);
        return;
    }
    
    /* if_open() function has triggered the polling routine
     * to determine the configured IP addresses.  Once the
     * addresses are found, trigger the chdlc configuration */
    if (test_bit(0,&chdlc_priv_area->config_chdlc)){

        chdlc_priv_area->ip_local_tmp  = get_ip_address(dev,WAN_LOCAL_IP);
        chdlc_priv_area->ip_remote_tmp = get_ip_address(dev,WAN_POINTOPOINT_IP);
    
           /* Jun 20. 2000 Bug Fix
         * Only perform this check in WANPIPE mode, since
         * IP addresses are not used in the API mode. */
    
        if (chdlc_priv_area->ip_local_tmp == chdlc_priv_area->ip_remote_tmp && 
            card->u.c.slarp_timer == 0x00 && 
            !card->u.c.backup && 
            card->u.c.usedby == WANPIPE){

            if (++chdlc_priv_area->ip_error > MAX_IP_ERRORS){
                printk(KERN_INFO "\n%s: --- WARNING ---\n",
                        card->devname);
                printk(KERN_INFO 
                "%s: The local IP address is the same as the\n",
                        card->devname);
                printk(KERN_INFO 
                "%s: Point-to-Point IP address.\n",
                        card->devname);
                printk(KERN_INFO "%s: --- WARNING ---\n\n",
                        card->devname);
            }else{
                clear_bit(POLL_CRIT,&card->wandev.critical);
                chdlc_priv_area->poll_delay_timer.expires = jiffies+HZ;
                add_timer(&chdlc_priv_area->poll_delay_timer);
                return;
            }
        }

        clear_bit(0,&chdlc_priv_area->config_chdlc);
        clear_bit(POLL_CRIT,&card->wandev.critical);
        
        chdlc_priv_area->timer_int_enabled |= TMR_INT_ENABLED_CONFIG;
        flags->interrupt_info_struct.interrupt_permission |= APP_INT_ON_TIMER;
        return;
    }
    /* Dynamic interface implementation, as well as dynamic
     * routing.  */
    
    switch (card->u.c.state){

    case WAN_DISCONNECTED:

        /* If the dynamic interface configuration is on, and interface 
         * is up, then bring down the netowrk interface */
        
        if (test_bit(DYN_OPT_ON,&chdlc_priv_area->interface_down) && 
            !test_bit(DEV_DOWN,  &chdlc_priv_area->interface_down) &&        
            card->wandev.dev->flags & IFF_UP){    

            printk(KERN_INFO "%s: Interface %s down.\n",
                card->devname,card->wandev.dev->name);
            change_dev_flags(card->wandev.dev,(card->wandev.dev->flags&~IFF_UP));
            set_bit(DEV_DOWN,&chdlc_priv_area->interface_down);
            chdlc_priv_area->route_status = NO_ROUTE;

        }else{
            /* We need to check if the local IP address is
                          * zero. If it is, we shouldn't try to remove it.
                      */

            if (card->wandev.dev->flags & IFF_UP && 
                    get_ip_address(card->wandev.dev,WAN_LOCAL_IP) && 
                    chdlc_priv_area->route_status != NO_ROUTE &&
                card->u.c.slarp_timer){

                process_route(card);
            }
        }
        break;

    case WAN_CONNECTED:

        /* In SMP machine this code can execute before the interface
         * comes up.  In this case, we must make sure that we do not
         * try to bring up the interface before dev_open() is finished */


        /* DEV_DOWN will be set only when we bring down the interface
         * for the very first time. This way we know that it was us
         * that brought the interface down */
        
        if (test_bit(DYN_OPT_ON,&chdlc_priv_area->interface_down) &&
            test_bit(DEV_DOWN,  &chdlc_priv_area->interface_down) &&
            !(card->wandev.dev->flags & IFF_UP)){
            
            printk(KERN_INFO "%s: Interface %s up.\n",
                card->devname,card->wandev.dev->name);
            change_dev_flags(card->wandev.dev,(card->wandev.dev->flags|IFF_UP));
            clear_bit(DEV_DOWN,&chdlc_priv_area->interface_down);
            check_gateway=1;
        }

        if (chdlc_priv_area->route_status == ADD_ROUTE && 
            card->u.c.slarp_timer){ 

            process_route(card);
            check_gateway=1;
        }

        if (chdlc_priv_area->gateway && check_gateway)
            add_gateway(card,dev);

        break;
    }    

    clear_bit(POLL_CRIT,&card->wandev.critical);
}

/*============================================================
 * trigger_chdlc_poll
 *
 * Description:
 *     Add a chdlc_poll() task into a tq_scheduler bh handler
 *      for a specific dlci/interface.  This will kick
 *      the fr_poll() routine at a later time. 
 *
 * Usage:
 *     Interrupts use this to defer a taks to 
 *      a polling routine.
 *
 */    
static void trigger_chdlc_poll (netdevice_t *dev)
{
    chdlc_private_area_t *chdlc_priv_area;
    sdla_t *card;

    if (!dev)
        return;
    
    if ((chdlc_priv_area = dev->priv)==NULL)
        return;

    card = chdlc_priv_area->card;
    
    if (test_and_set_bit(POLL_CRIT,&card->wandev.critical)){
        return;
    }
    if (test_bit(PERI_CRIT,&card->wandev.critical)){
        return; 
    }
#ifdef LINUX_2_4
    schedule_task(&chdlc_priv_area->poll_task);
#else
    queue_task(&chdlc_priv_area->poll_task, &tq_scheduler);
#endif
    return;
}


static void chdlc_poll_delay (unsigned long dev_ptr)
{
    netdevice_t *dev = (netdevice_t *)dev_ptr;
    trigger_chdlc_poll(dev);
}


void s508_lock (sdla_t *card, unsigned long *smp_flags)
{
#if defined(__SMP__) || defined(LINUX_2_4)
    spin_lock_irqsave(&card->wandev.lock, *smp_flags);
        if (card->next){
            spin_lock(&card->next->wandev.lock);
    }
#else
        disable_irq(card->hw.irq);
#endif                                                                     
}

void s508_unlock (sdla_t *card, unsigned long *smp_flags)
{
#if defined(__SMP__) || defined(LINUX_2_4)
        if (card->next){
            spin_unlock(&card->next->wandev.lock);
        }
        spin_unlock_irqrestore(&card->wandev.lock, *smp_flags);
#else
        enable_irq(card->hw.irq);
#endif           
}

//*********** TTY SECTION ****************
#if defined(LINUX_2_4) || defined(LINUX_2_1)

static void wanpipe_tty_trigger_tx_irq(sdla_t *card)
{
    SHARED_MEMORY_INFO_STRUCT *flags = card->u.c.flags;
    INTERRUPT_INFORMATION_STRUCT *chdlc_int = &flags->interrupt_info_struct;
    chdlc_int->interrupt_permission |= APP_INT_ON_TX_FRAME;
}

static void wanpipe_tty_trigger_poll(sdla_t *card)
{
#ifdef LINUX_2_4
    schedule_task(&card->tty_task_queue);
#else
    queue_task(&card->tty_task_queue, &tq_scheduler);
#endif
}

static void tty_poll_task (void* data)
{
    sdla_t *card = (sdla_t*)data;
    struct tty_struct *tty;

    if ((tty=card->tty)==NULL)
        return;
    
    if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
        tty->ldisc.write_wakeup){
        (tty->ldisc.write_wakeup)(tty);
    }
    wake_up_interruptible(&tty->write_wait);
#if defined(SERIAL_HAVE_POLL_WAIT) || \
         (defined LINUX_2_1 && LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,15))
    wake_up_interruptible(&tty->poll_wait);
#endif    
    return;
}

static void wanpipe_tty_close(struct tty_struct *tty, struct file * filp)
{
    sdla_t *card;
    unsigned long smp_flags;
    
    if (!tty || !tty->driver_data){
        return;
    }
    
    card = (sdla_t*)tty->driver_data;
    
    if (!card)
        return;

    printk(KERN_INFO "%s: Closing TTY Driver!\n",
            card->devname);

    /* Sanity Check */
    if (!card->tty_open)
        return;
    
    wanpipe_close(card);
    if (--card->tty_open == 0){

        lock_adapter_irq(&card->wandev.lock,&smp_flags);    
        card->tty=NULL;
        chdlc_disable_comm_shutdown(card);
        unlock_adapter_irq(&card->wandev.lock,&smp_flags);

        if (card->tty_buf){
            kfree(card->tty_buf);
            card->tty_buf=NULL;            
        }

        if (card->tty_rx){
            kfree(card->tty_rx);
            card->tty_rx=NULL;
        }
    }
    return;
}
static int wanpipe_tty_open(struct tty_struct *tty, struct file * filp)
{
    unsigned long smp_flags;
    sdla_t *card;
    
    if (!tty){
        return -ENODEV;
    }
    
    if (!tty->driver_data){
        int port;
        port = MINOR(tty->device) - tty->driver.minor_start;
        if ((port < 0) || (port >= NR_PORTS)) 
            return -ENODEV;
        
        tty->driver_data = WAN_CARD(port);
        if (!tty->driver_data)
            return -ENODEV;
    }

    card = (sdla_t*)tty->driver_data;

    if (!card){
        lock_adapter_irq(&card->wandev.lock,&smp_flags);    
        card->tty=NULL;
        unlock_adapter_irq(&card->wandev.lock,&smp_flags);
        return -ENODEV;
    }

    printk(KERN_INFO "%s: Opening TTY Driver!\n",
            card->devname);

    if (card->tty_open == 0){
        lock_adapter_irq(&card->wandev.lock,&smp_flags);    
        card->tty=tty;
        unlock_adapter_irq(&card->wandev.lock,&smp_flags);

        if (!card->tty_buf){
            card->tty_buf = kmalloc(TTY_CHDLC_MAX_MTU, GFP_KERNEL);
            if (!card->tty_buf){
                card->tty_buf=NULL;
                card->tty=NULL;
                return -ENOMEM;    
            }
        }

        if (!card->tty_rx){
            card->tty_rx = kmalloc(TTY_CHDLC_MAX_MTU, GFP_KERNEL);
            if (!card->tty_rx){
                /* Free the buffer above */
                kfree(card->tty_buf);
                card->tty_buf=NULL;
                card->tty=NULL;
                return -ENOMEM;    
            }
        }
    }

    ++card->tty_open;
    wanpipe_open(card);
    return 0;
}

static int wanpipe_tty_write(struct tty_struct * tty, int from_user,
            const unsigned char *buf, int count)
{
    unsigned long smp_flags=0;
    sdla_t *card=NULL;

    if (!tty){
        dbg_printk(KERN_INFO "NO TTY in Write\n");
        return -ENODEV;
    }

    card = (sdla_t *)tty->driver_data;
            
    if (!card){
        dbg_printk(KERN_INFO "No Card in TTY Write\n");
        return -ENODEV;
    }    

    if (count > card->wandev.mtu){
        dbg_printk(KERN_INFO "Frame too big in Write %i Max: %i\n",
                count,card->wandev.mtu);
        return -EINVAL;
    }
    
    if (card->wandev.state != WAN_CONNECTED){
        dbg_printk(KERN_INFO "Card not connected in TTY Write\n");
        return -EINVAL;
    }

    /* Lock the 508 Card: SMP is supported */
          if(card->hw.type != SDLA_S514){
        s508_lock(card,&smp_flags);
    } 
    
    if (test_and_set_bit(SEND_CRIT,(void*)&card->wandev.critical)){
        printk(KERN_INFO "%s: Critical in TTY Write\n",
                card->devname);
        
        /* Lock the 508 Card: SMP is supported */
        if(card->hw.type != SDLA_S514)
            s508_unlock(card,&smp_flags);
        
        return -EINVAL; 
    }
    
    if (from_user) {
        
        unsigned char *tmp_buf;
        
        if ((tmp_buf=card->tty_buf)==NULL){
            dbg_printk(KERN_INFO "No TTY BUF in Write\n");
            
            clear_bit(SEND_CRIT,(void*)&card->wandev.critical);
            
            if(card->hw.type != SDLA_S514)
                s508_unlock(card,&smp_flags);
            
            return -ENOMEM;
        }
        
        if (copy_from_user(tmp_buf,buf,count)){
            dbg_printk(KERN_INFO "%s: Failed to copy from user!\n",
                    card->devname);
            
            clear_bit(SEND_CRIT,(void*)&card->wandev.critical);
            
            if(card->hw.type != SDLA_S514)
                s508_unlock(card,&smp_flags);
            
            return -EINVAL;
        }

        if (chdlc_send(card,(void*)tmp_buf,count)){
            dbg_printk(KERN_INFO "%s: Failed to send, retry later: user!\n",
                    card->devname);
            
            clear_bit(SEND_CRIT,(void*)&card->wandev.critical);
            
            wanpipe_tty_trigger_tx_irq(card);
            
            if(card->hw.type != SDLA_S514)
                s508_unlock(card,&smp_flags);
            return 0;
        }

    }else{
         if (chdlc_send(card,(void*)buf,count)){
            dbg_printk(KERN_INFO "%s: Failed to send, retry later: kernel!\n",
                    card->devname);
            clear_bit(SEND_CRIT,(void*)&card->wandev.critical);
    
            wanpipe_tty_trigger_tx_irq(card);
            
            if(card->hw.type != SDLA_S514)
                s508_unlock(card,&smp_flags);
            return 0;
        }
    }
    dbg_printk(KERN_INFO "%s: Packet sent OK: %i\n",card->devname,count);
    clear_bit(SEND_CRIT,(void*)&card->wandev.critical);
    
    if(card->hw.type != SDLA_S514)
        s508_unlock(card,&smp_flags);

    return count;
}

static void wanpipe_tty_receive(sdla_t *card, unsigned addr, unsigned int len)
{
    unsigned offset=0;
    unsigned olen=len;
    char fp=0;
    struct tty_struct *tty;
    int i;
    
    if (!card->tty_open){
        dbg_printk(KERN_INFO "%s: TTY not open during receive\n",
                card->devname);
        return;
    }
    
    if ((tty=card->tty) == NULL){
        dbg_printk(KERN_INFO "%s: No TTY on receive\n",
                card->devname);
        return;
    }
    
    if (!tty->driver_data){
        dbg_printk(KERN_INFO "%s: No Driver Data, or Flip on receive\n",
                card->devname);
        return;
    }
    

    if (card->u.c.async_mode){
        if ((tty->flip.count+len) >= TTY_FLIPBUF_SIZE){
            if (net_ratelimit()){
                printk(KERN_INFO 
                    "%s: Received packet size too big: %i bytes, Max: %i!\n",
                    card->devname,len,TTY_FLIPBUF_SIZE);
            }
            return;
        }

        
        if((addr + len) > card->u.c.rx_top + 1) {
            offset = card->u.c.rx_top - addr + 1;
            
            sdla_peek(&card->hw, addr, tty->flip.char_buf_ptr, offset);
            
            addr = card->u.c.rx_base;
            len -= offset;
            
            tty->flip.char_buf_ptr+=offset;
            tty->flip.count+=offset;
            for (i=0;i<offset;i++){
                *tty->flip.flag_buf_ptr = 0;
                tty->flip.flag_buf_ptr++;
            }
        }
        
        sdla_peek(&card->hw, addr, tty->flip.char_buf_ptr, len);
            
        tty->flip.char_buf_ptr+=len;
        card->tty->flip.count+=len;
        for (i=0;i<len;i++){
            *tty->flip.flag_buf_ptr = 0;
            tty->flip.flag_buf_ptr++;
        }

        tty->low_latency=1;
        tty_flip_buffer_push(tty);
    }else{
        if (!card->tty_rx){    
            if (net_ratelimit()){
                printk(KERN_INFO 
                "%s: Receive sync buffer not available!\n",
                 card->devname);
            }
            return;
        }
    
        if (len > TTY_CHDLC_MAX_MTU){
            if (net_ratelimit()){
                printk(KERN_INFO 
                "%s: Received packet size too big: %i bytes, Max: %i!\n",
                    card->devname,len,TTY_FLIPBUF_SIZE);
            }
            return;
        }

        
        if((addr + len) > card->u.c.rx_top + 1) {
            offset = card->u.c.rx_top - addr + 1;
            
            sdla_peek(&card->hw, addr, card->tty_rx, offset);
            
            addr = card->u.c.rx_base;
            len -= offset;
        }
        sdla_peek(&card->hw, addr, card->tty_rx+offset, len);
        if (tty->ldisc.receive_buf){
            tty->ldisc.receive_buf(tty,card->tty_rx,&fp,olen);
        }else{
            if (net_ratelimit()){
                printk(KERN_INFO 
                    "%s: NO TTY Sync line discipline!\n",
                    card->devname);
            }
        }
    }

    dbg_printk(KERN_INFO "%s: Received Data %i\n",card->devname,olen);
    return;
}

#if 0
static int wanpipe_tty_ioctl(struct tty_struct *tty, struct file * file,
            unsigned int cmd, unsigned long arg)
{
    return -ENOIOCTLCMD;
}
#endif

static void wanpipe_tty_stop(struct tty_struct *tty)
{
    return;
}

static void wanpipe_tty_start(struct tty_struct *tty)
{
    return;
}

static int config_tty (sdla_t *card)
{
    SHARED_MEMORY_INFO_STRUCT *flags = card->u.c.flags;

    /* Setup the Board for asynchronous mode */
    if (card->u.c.async_mode){
        
        if (set_asy_config(card)) {
            printk (KERN_INFO "%s: Failed CHDLC Async configuration!\n",
                card->devname);
            return -EINVAL;
        }
    }else{
        /* Setup the Board for CHDLC */
        if (set_chdlc_config(card)) {
            printk (KERN_INFO "%s: Failed CHDLC configuration!\n",
                card->devname);
            return -EINVAL;
        }
    }

    /* Set interrupt mode and mask */
        if (chdlc_set_intr_mode(card, APP_INT_ON_RX_FRAME |
                        APP_INT_ON_GLOBAL_EXCEP_COND |
                        APP_INT_ON_TX_FRAME |
                        APP_INT_ON_CHDLC_EXCEP_COND | APP_INT_ON_TIMER)){
        printk (KERN_INFO "%s: Failed to set interrupt triggers!\n",
                card->devname);
        return -EINVAL;    
        }
    

    /* Mask the Transmit and Timer interrupt */
    flags->interrupt_info_struct.interrupt_permission &= 
        ~(APP_INT_ON_TX_FRAME | APP_INT_ON_TIMER);

    
    /* Enable communications */
     if (card->u.c.async_mode){
        if (asy_comm_enable(card) != 0) {
            printk(KERN_INFO "%s: Failed to enable async commnunication!\n",
                    card->devname);
            flags->interrupt_info_struct.interrupt_permission = 0;
            card->u.c.comm_enabled=0;
            chdlc_set_intr_mode(card,0);
            return -EINVAL;
        }
        }else{ 
        if (chdlc_comm_enable(card) != 0) {
            printk(KERN_INFO "%s: Failed to enable chdlc communications!\n",
                    card->devname);
            flags->interrupt_info_struct.interrupt_permission = 0;
            card->u.c.comm_enabled=0;
            chdlc_set_intr_mode(card,0);
            return -EINVAL;
        }
    }

    /* Initialize Rx/Tx buffer control fields */
    init_chdlc_tx_rx_buff(card);
    port_set_state(card, WAN_CONNECTING);
    return 0; 
}


static int change_speed(sdla_t *card, struct tty_struct *tty,
             struct termios *old_termios)
{
    int    baud, ret=0;
    unsigned cflag; 
    int    dbits,sbits,parity,handshaking;

    cflag = tty->termios->c_cflag;

    /* There is always one stop bit */
    sbits=WANOPT_ONE;
    
    /* Parity is defaulted to NONE */
    parity = WANOPT_NONE;

    handshaking=0;
    
    /* byte size and parity */
    switch (cflag & CSIZE) {
          case CS5: dbits = 5; break;
          case CS6: dbits = 6; break;
          case CS7: dbits = 7; break;
          case CS8: dbits = 8; break;
          /* Never happens, but GCC is too dumb to figure it out */
          default:  dbits = 8; break;
    }
    
    /* One more stop bit should be supported, thus increment
     * the number of stop bits Max=2 */
    if (cflag & CSTOPB) {
        sbits = WANOPT_TWO;
    }
    if (cflag & PARENB) {
        parity = WANOPT_EVEN;
    }
    if (cflag & PARODD){
        parity = WANOPT_ODD;
    }

    /* Determine divisor based on baud rate */
    baud = tty_get_baud_rate(tty);

    if (!baud)
        baud = 9600;    /* B0 transition handled in rs_set_termios */

    if (cflag & CRTSCTS) {
        handshaking|=ASY_RTS_HS_FOR_RX;
    }
    
    if (I_IGNPAR(tty))
        parity = WANOPT_NONE;

    if (I_IXOFF(tty)){
        handshaking|=ASY_XON_XOFF_HS_FOR_RX;
        handshaking|=ASY_XON_XOFF_HS_FOR_TX;
    }

    if (I_IXON(tty)){
        handshaking|=ASY_XON_XOFF_HS_FOR_RX;
        handshaking|=ASY_XON_XOFF_HS_FOR_TX;
    }

    if (card->u.c.async_mode){
        if (card->wandev.bps != baud)
            ret=1;
        card->wandev.bps = baud;
    }

    if (card->u.c.async_mode){
        if (card->u.c.protocol_options != handshaking)
            ret=1;
        card->u.c.protocol_options = handshaking;

        if (card->u.c.tx_bits_per_char != dbits)
            ret=1;
        card->u.c.tx_bits_per_char = dbits;

        if (card->u.c.rx_bits_per_char != dbits)
            ret=1;
        card->u.c.rx_bits_per_char = dbits;
        
        if (card->u.c.stop_bits != sbits)
            ret=1;
        card->u.c.stop_bits = sbits;

        if (card->u.c.parity != parity)
            ret=1;
        card->u.c.parity = parity;    

        card->u.c.break_timer = 50;
        card->u.c.inter_char_timer = 10;
        card->u.c.rx_complete_length = 100;
        card->u.c.xon_char = 0xFE;
    }else{
        card->u.c.protocol_options = HDLC_STREAMING_MODE;
    }
    
    return ret;
}

    
static void wanpipe_tty_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
    sdla_t *card;
    int err=1;

    if (!tty){
        return;
    }

    card = (sdla_t *)tty->driver_data;
            
    if (!card)
        return;

    if (change_speed(card, tty, old_termios) || !card->u.c.comm_enabled){
        unsigned long smp_flags;
        
        if (card->u.c.comm_enabled){
            lock_adapter_irq(&card->wandev.lock,&smp_flags);
            chdlc_disable_comm_shutdown(card);
            unlock_adapter_irq(&card->wandev.lock,&smp_flags);
        }
        lock_adapter_irq(&card->wandev.lock,&smp_flags);
        err = config_tty(card);
        unlock_adapter_irq(&card->wandev.lock,&smp_flags);
        if (card->u.c.async_mode){
            printk(KERN_INFO "%s: TTY Async Configuration:\n"
                 "   Baud        =%i\n"
                 "   Handshaking =%s\n"
                 "   Tx Dbits    =%i\n"
                 "   Rx Dbits    =%i\n"
                 "   Parity      =%s\n"
                 "   Stop Bits   =%i\n",
                 card->devname,
                 card->wandev.bps,
                 opt_decode[card->u.c.protocol_options],
                 card->u.c.tx_bits_per_char,
                 card->u.c.rx_bits_per_char,
                 p_decode[card->u.c.parity] ,
                 card->u.c.stop_bits);
        }else{
            printk(KERN_INFO "%s: TTY Sync Configuration:\n"
                 "   Baud        =%i\n"
                 "   Protocol    =HDLC_STREAMING\n",
                 card->devname,card->wandev.bps);
        }
        if (!err){
            port_set_state(card,WAN_CONNECTED);
        }else{
            port_set_state(card,WAN_DISCONNECTED);
        }
    }
    return;
}

static void wanpipe_tty_put_char(struct tty_struct *tty, unsigned char ch)
{
    sdla_t *card;
    unsigned long smp_flags=0;

    if (!tty){
        return;
    }
    
    card = (sdla_t *)tty->driver_data;
            
    if (!card)
        return;

    if (card->wandev.state != WAN_CONNECTED)
        return;

    if(card->hw.type != SDLA_S514)
        s508_lock(card,&smp_flags);
    
    if (test_and_set_bit(SEND_CRIT,(void*)&card->wandev.critical)){
        
        wanpipe_tty_trigger_tx_irq(card);

        if(card->hw.type != SDLA_S514)
            s508_unlock(card,&smp_flags);
        return;
    }

    if (chdlc_send(card,(void*)&ch,1)){
        wanpipe_tty_trigger_tx_irq(card);
        dbg_printk("%s: Failed to TX char!\n",card->devname);
    }
    
    dbg_printk("%s: Char TX OK\n",card->devname);
    
    clear_bit(SEND_CRIT,(void*)&card->wandev.critical);
    
    if(card->hw.type != SDLA_S514)
        s508_unlock(card,&smp_flags);
    
    return;
}

static void wanpipe_tty_flush_chars(struct tty_struct *tty)
{
    return;
}

static void wanpipe_tty_flush_buffer(struct tty_struct *tty)
{
    if (!tty)
        return;
    
    wake_up_interruptible(&tty->write_wait);
#if defined(SERIAL_HAVE_POLL_WAIT) || \
         (defined LINUX_2_1 && LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,15))
    wake_up_interruptible(&tty->poll_wait);
#endif
    if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
        tty->ldisc.write_wakeup)
        (tty->ldisc.write_wakeup)(tty);

    return;
}

/*
 * This function is used to send a high-priority XON/XOFF character to
 * the device
 */
static void wanpipe_tty_send_xchar(struct tty_struct *tty, char ch)
{
    return;
}


static int wanpipe_tty_chars_in_buffer(struct tty_struct *tty)
{
    return 0;
}


static int wanpipe_tty_write_room(struct tty_struct *tty)
{
    sdla_t *card;

    printk(KERN_INFO "TTY Write Room\n");
    
    if (!tty){
        return 0;
    }

    card = (sdla_t *)tty->driver_data;
    if (!card)
        return 0;

    if (card->wandev.state != WAN_CONNECTED)
        return 0;
    
    return SEC_MAX_NO_DATA_BYTES_IN_FRAME;
}


static int set_modem_status(sdla_t *card, unsigned char data)
{
    CHDLC_MAILBOX_STRUCT *mb = card->mbox;
    int err;

    mb->buffer_length=1;
    mb->command=SET_MODEM_STATUS;
    mb->data[0]=data;
    err = sdla_exec(mb) ? mb->return_code : CMD_TIMEOUT;
    if (err != COMMAND_OK) 
        chdlc_error (card, err, mb);
    
    return err;
}

static void wanpipe_tty_hangup(struct tty_struct *tty)
{
    sdla_t *card;
    unsigned long smp_flags;

    printk(KERN_INFO "TTY Hangup!\n");
    
    if (!tty){
        return;
    }

    card = (sdla_t *)tty->driver_data;
    if (!card)
        return;

    lock_adapter_irq(&card->wandev.lock,&smp_flags);
    set_modem_status(card,0);
    unlock_adapter_irq(&card->wandev.lock,&smp_flags);
    return;
}

static void wanpipe_tty_break(struct tty_struct *tty, int break_state)
{
    return;
}

static void wanpipe_tty_wait_until_sent(struct tty_struct *tty, int timeout)
{
    return;
}

static void wanpipe_tty_throttle(struct tty_struct * tty)
{
    return;
}

static void wanpipe_tty_unthrottle(struct tty_struct * tty)
{
    return;
}

int wanpipe_tty_read_proc(char *page, char **start, off_t off, int count,
         int *eof, void *data)
{
    return 0;
}

/*
 * The serial driver boot-time initialization code!
 */
int wanpipe_tty_init(sdla_t *card)
{
    struct serial_state * state;
    
    /* Initialize the tty_driver structure */

    if (card->tty_minor < 0 || card->tty_minor > NR_PORTS){
        printk(KERN_INFO "%s: Illegal Minor TTY number (0-4): %i\n",
                card->devname,card->tty_minor);
        return -EINVAL;
    }

    if (WAN_CARD(card->tty_minor)){
        printk(KERN_INFO "%s: TTY Minor %i, already in use\n",
                card->devname,card->tty_minor);
        return -EBUSY;
    }

    if (tty_init_cnt==0){
        
        printk(KERN_INFO "%s: TTY %s Driver Init: Major %i, Minor Range %i-%i\n",
                card->devname,
                card->u.c.async_mode ? "ASYNC" : "SYNC",
                WAN_TTY_MAJOR,MIN_PORT,MAX_PORT);
        
        tty_driver_mode = card->u.c.async_mode;
        
        memset(&serial_driver, 0, sizeof(struct tty_driver));
        serial_driver.magic = TTY_DRIVER_MAGIC;
        serial_driver.driver_name = "wanpipe_tty"; 
        serial_driver.name = "ttyW";
        serial_driver.major = WAN_TTY_MAJOR;
        serial_driver.minor_start = WAN_TTY_MINOR;
        serial_driver.num = NR_PORTS; 
        serial_driver.type = TTY_DRIVER_TYPE_SERIAL;
        serial_driver.subtype = SERIAL_TYPE_NORMAL;
        
        serial_driver.init_termios = tty_std_termios;
        serial_driver.init_termios.c_cflag =
            B9600 | CS8 | CREAD | HUPCL | CLOCAL;
        serial_driver.flags = TTY_DRIVER_REAL_RAW;
        
        serial_driver.refcount = &serial_refcount;
        serial_driver.table = serial_table;
        serial_driver.termios = serial_termios;
        serial_driver.termios_locked = serial_termios_locked;

        serial_driver.open = wanpipe_tty_open;
        serial_driver.close = wanpipe_tty_close;
        serial_driver.write = wanpipe_tty_write;
        
        serial_driver.put_char = wanpipe_tty_put_char;
        serial_driver.flush_chars = wanpipe_tty_flush_chars;
        serial_driver.write_room = wanpipe_tty_write_room;
        serial_driver.chars_in_buffer = wanpipe_tty_chars_in_buffer;
        serial_driver.flush_buffer = wanpipe_tty_flush_buffer;
        //serial_driver.ioctl = wanpipe_tty_ioctl;
        serial_driver.throttle = wanpipe_tty_throttle;
        serial_driver.unthrottle = wanpipe_tty_unthrottle;
        serial_driver.send_xchar = wanpipe_tty_send_xchar;
        serial_driver.set_termios = wanpipe_tty_set_termios;
        serial_driver.stop = wanpipe_tty_stop;
        serial_driver.start = wanpipe_tty_start;
        serial_driver.hangup = wanpipe_tty_hangup;
        serial_driver.break_ctl = wanpipe_tty_break;
        serial_driver.wait_until_sent = wanpipe_tty_wait_until_sent;
        serial_driver.read_proc = wanpipe_tty_read_proc;
        
        /*
         * The callout device is just like normal device except for
         * major number and the subtype code.
         */
        callout_driver = serial_driver;
        callout_driver.name = "cuw";
        callout_driver.major = TTYAUX_MAJOR;
        callout_driver.subtype = SERIAL_TYPE_CALLOUT;
        callout_driver.read_proc = 0;
        callout_driver.proc_entry = 0;

        if (tty_register_driver(&serial_driver)){
            printk(KERN_INFO "%s: Failed to register serial driver!\n",
                    card->devname);
        }

        if (tty_register_driver(&callout_driver)){
            printk(KERN_INFO "%s: Failed to register callout driver!\n",
                    card->devname);
        }

    }


    /* The subsequent ports must comply to the initial configuration */
    if (tty_driver_mode != card->u.c.async_mode){
        printk(KERN_INFO "%s: Error: TTY Driver operation mode mismatch!\n",
                card->devname);
        printk(KERN_INFO "%s: The TTY driver is configured for %s!\n",
                card->devname, tty_driver_mode ? "ASYNC" : "SYNC");
        return -EINVAL;
    }
    
    tty_init_cnt++;
    
    printk(KERN_INFO "%s: Initializing TTY %s Driver Minor %i\n",
            card->devname,
            tty_driver_mode ? "ASYNC" : "SYNC",
            card->tty_minor);
    
    tty_card_map[card->tty_minor] = card;
    state = &rs_table[card->tty_minor];
    
    state->magic = SSTATE_MAGIC;
    state->line = 0;
    state->type = PORT_UNKNOWN;
    state->custom_divisor = 0;
    state->close_delay = 5*HZ/10;
    state->closing_wait = 30*HZ;
    state->callout_termios = callout_driver.init_termios;
    state->normal_termios = serial_driver.init_termios;
    state->icount.cts = state->icount.dsr = 
        state->icount.rng = state->icount.dcd = 0;
    state->icount.rx = state->icount.tx = 0;
    state->icount.frame = state->icount.parity = 0;
    state->icount.overrun = state->icount.brk = 0;
    state->irq = card->wandev.irq; 

    card->tty_task_queue.routine = tty_poll_task;
    card->tty_task_queue.data = (void*)card;
    return 0;
}

#endif


MODULE_LICENSE("GPL");

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