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synclink_cs.c

/*
 * linux/drivers/char/pcmcia/synclink_cs.c
 *
 * $Id: synclink_cs.c,v 4.34 2005/09/08 13:20:54 paulkf Exp $
 *
 * Device driver for Microgate SyncLink PC Card
 * multiprotocol serial adapter.
 *
 * written by Paul Fulghum for Microgate Corporation
 * paulkf@microgate.com
 *
 * Microgate and SyncLink are trademarks of Microgate Corporation
 *
 * This code is released under the GNU General Public License (GPL)
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#define VERSION(ver,rel,seq) (((ver)<<16) | ((rel)<<8) | (seq))
#if defined(__i386__)
#  define BREAKPOINT() asm("   int $3");
#else
#  define BREAKPOINT() { }
#endif

#define MAX_DEVICE_COUNT 4

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/ioctl.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/dma.h>
#include <linux/bitops.h>
#include <asm/types.h>
#include <linux/termios.h>
#include <linux/workqueue.h>
#include <linux/hdlc.h>

#include <pcmcia/cs_types.h>
#include <pcmcia/cs.h>
#include <pcmcia/cistpl.h>
#include <pcmcia/cisreg.h>
#include <pcmcia/ds.h>

#if defined(CONFIG_HDLC) || (defined(CONFIG_HDLC_MODULE) && defined(CONFIG_SYNCLINK_CS_MODULE))
#define SYNCLINK_GENERIC_HDLC 1
#else
#define SYNCLINK_GENERIC_HDLC 0
#endif

#define GET_USER(error,value,addr) error = get_user(value,addr)
#define COPY_FROM_USER(error,dest,src,size) error = copy_from_user(dest,src,size) ? -EFAULT : 0
#define PUT_USER(error,value,addr) error = put_user(value,addr)
#define COPY_TO_USER(error,dest,src,size) error = copy_to_user(dest,src,size) ? -EFAULT : 0

#include <asm/uaccess.h>

#include "linux/synclink.h"

static MGSL_PARAMS default_params = {
      MGSL_MODE_HDLC,               /* unsigned long mode */
      0,                      /* unsigned char loopback; */
      HDLC_FLAG_UNDERRUN_ABORT15,   /* unsigned short flags; */
      HDLC_ENCODING_NRZI_SPACE,     /* unsigned char encoding; */
      0,                      /* unsigned long clock_speed; */
      0xff,                   /* unsigned char addr_filter; */
      HDLC_CRC_16_CCITT,            /* unsigned short crc_type; */
      HDLC_PREAMBLE_LENGTH_8BITS,   /* unsigned char preamble_length; */
      HDLC_PREAMBLE_PATTERN_NONE,   /* unsigned char preamble; */
      9600,                   /* unsigned long data_rate; */
      8,                      /* unsigned char data_bits; */
      1,                      /* unsigned char stop_bits; */
      ASYNC_PARITY_NONE       /* unsigned char parity; */
};

typedef struct
{
      int count;
      unsigned char status;
      char data[1];
} RXBUF;

/* The queue of BH actions to be performed */

#define BH_RECEIVE  1
#define BH_TRANSMIT 2
#define BH_STATUS   4

#define IO_PIN_SHUTDOWN_LIMIT 100

#define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))

struct _input_signal_events {
      int   ri_up;
      int   ri_down;
      int   dsr_up;
      int   dsr_down;
      int   dcd_up;
      int   dcd_down;
      int   cts_up;
      int   cts_down;
};


/*
 * Device instance data structure
 */

typedef struct _mgslpc_info {
      void *if_ptr;     /* General purpose pointer (used by SPPP) */
      int               magic;
      int               flags;
      int               count;            /* count of opens */
      int               line;
      unsigned short          close_delay;
      unsigned short          closing_wait;     /* time to wait before closing */

      struct mgsl_icount      icount;

      struct tty_struct       *tty;
      int               timeout;
      int               x_char;           /* xon/xoff character */
      int               blocked_open;     /* # of blocked opens */
      unsigned char           read_status_mask;
      unsigned char           ignore_status_mask;

      unsigned char *tx_buf;
      int            tx_put;
      int            tx_get;
      int            tx_count;

      /* circular list of fixed length rx buffers */

      unsigned char  *rx_buf;        /* memory allocated for all rx buffers */
      int            rx_buf_total_size; /* size of memory allocated for rx buffers */
      int            rx_put;         /* index of next empty rx buffer */
      int            rx_get;         /* index of next full rx buffer */
      int            rx_buf_size;    /* size in bytes of single rx buffer */
      int            rx_buf_count;   /* total number of rx buffers */
      int            rx_frame_count; /* number of full rx buffers */

      wait_queue_head_t open_wait;
      wait_queue_head_t close_wait;

      wait_queue_head_t status_event_wait_q;
      wait_queue_head_t event_wait_q;
      struct timer_list tx_timer;   /* HDLC transmit timeout timer */
      struct _mgslpc_info     *next_device;     /* device list link */

      unsigned short imra_value;
      unsigned short imrb_value;
      unsigned char  pim_value;

      spinlock_t lock;
      struct work_struct task;            /* task structure for scheduling bh */

      u32 max_frame_size;

      u32 pending_bh;

      int bh_running;
      int bh_requested;

      int dcd_chkcount; /* check counts to prevent */
      int cts_chkcount; /* too many IRQs if a signal */
      int dsr_chkcount; /* is floating */
      int ri_chkcount;

      int rx_enabled;
      int rx_overflow;

      int tx_enabled;
      int tx_active;
      int tx_aborting;
      u32 idle_mode;

      int if_mode; /* serial interface selection (RS-232, v.35 etc) */

      char device_name[25];         /* device instance name */

      unsigned int io_base;   /* base I/O address of adapter */
      unsigned int irq_level;

      MGSL_PARAMS params;           /* communications parameters */

      unsigned char serial_signals; /* current serial signal states */

      char irq_occurred;            /* for diagnostics use */
      char testing_irq;
      unsigned int init_error;      /* startup error (DIAGS)      */

      char flag_buf[MAX_ASYNC_BUFFER_SIZE];
      BOOLEAN drop_rts_on_tx_done;

      struct      _input_signal_events    input_signal_events;

      /* PCMCIA support */
      struct pcmcia_device    *p_dev;
      dev_node_t        node;
      int               stop;

      /* SPPP/Cisco HDLC device parts */
      int netcount;
      int dosyncppp;
      spinlock_t netlock;

#if SYNCLINK_GENERIC_HDLC
      struct net_device *netdev;
#endif

} MGSLPC_INFO;

#define MGSLPC_MAGIC 0x5402

/*
 * The size of the serial xmit buffer is 1 page, or 4096 bytes
 */
#define TXBUFSIZE 4096


#define CHA     0x00   /* channel A offset */
#define CHB     0x40   /* channel B offset */

/*
 *  FIXME: PPC has PVR defined in asm/reg.h.  For now we just undef it.
 */
#undef PVR

#define RXFIFO  0
#define TXFIFO  0
#define STAR    0x20
#define CMDR    0x20
#define RSTA    0x21
#define PRE     0x21
#define MODE    0x22
#define TIMR    0x23
#define XAD1    0x24
#define XAD2    0x25
#define RAH1    0x26
#define RAH2    0x27
#define DAFO    0x27
#define RAL1    0x28
#define RFC     0x28
#define RHCR    0x29
#define RAL2    0x29
#define RBCL    0x2a
#define XBCL    0x2a
#define RBCH    0x2b
#define XBCH    0x2b
#define CCR0    0x2c
#define CCR1    0x2d
#define CCR2    0x2e
#define CCR3    0x2f
#define VSTR    0x34
#define BGR     0x34
#define RLCR    0x35
#define AML     0x36
#define AMH     0x37
#define GIS     0x38
#define IVA     0x38
#define IPC     0x39
#define ISR     0x3a
#define IMR     0x3a
#define PVR     0x3c
#define PIS     0x3d
#define PIM     0x3d
#define PCR     0x3e
#define CCR4    0x3f

// IMR/ISR

#define IRQ_BREAK_ON    BIT15   // rx break detected
#define IRQ_DATAOVERRUN BIT14 // receive data overflow
#define IRQ_ALLSENT     BIT13 // all sent
#define IRQ_UNDERRUN    BIT12 // transmit data underrun
#define IRQ_TIMER       BIT11 // timer interrupt
#define IRQ_CTS         BIT10 // CTS status change
#define IRQ_TXREPEAT    BIT9  // tx message repeat
#define IRQ_TXFIFO      BIT8  // transmit pool ready
#define IRQ_RXEOM       BIT7  // receive message end
#define IRQ_EXITHUNT    BIT6  // receive frame start
#define IRQ_RXTIME      BIT6    // rx char timeout
#define IRQ_DCD         BIT2  // carrier detect status change
#define IRQ_OVERRUN     BIT1  // receive frame overflow
#define IRQ_RXFIFO      BIT0  // receive pool full

// STAR

#define XFW   BIT6            // transmit FIFO write enable
#define CEC   BIT2            // command executing
#define CTS   BIT1            // CTS state

#define PVR_DTR      BIT0
#define PVR_DSR      BIT1
#define PVR_RI       BIT2
#define PVR_AUTOCTS  BIT3
#define PVR_RS232    0x20   /* 0010b */
#define PVR_V35      0xe0   /* 1110b */
#define PVR_RS422    0x40   /* 0100b */

/* Register access functions */

#define write_reg(info, reg, val) outb((val),(info)->io_base + (reg))
#define read_reg(info, reg) inb((info)->io_base + (reg))

#define read_reg16(info, reg) inw((info)->io_base + (reg))
#define write_reg16(info, reg, val) outw((val), (info)->io_base + (reg))

#define set_reg_bits(info, reg, mask) \
    write_reg(info, (reg), \
             (unsigned char) (read_reg(info, (reg)) | (mask)))
#define clear_reg_bits(info, reg, mask) \
    write_reg(info, (reg), \
             (unsigned char) (read_reg(info, (reg)) & ~(mask)))
/*
 * interrupt enable/disable routines
 */
static void irq_disable(MGSLPC_INFO *info, unsigned char channel, unsigned short mask)
{
      if (channel == CHA) {
            info->imra_value |= mask;
            write_reg16(info, CHA + IMR, info->imra_value);
      } else {
            info->imrb_value |= mask;
            write_reg16(info, CHB + IMR, info->imrb_value);
      }
}
static void irq_enable(MGSLPC_INFO *info, unsigned char channel, unsigned short mask)
{
      if (channel == CHA) {
            info->imra_value &= ~mask;
            write_reg16(info, CHA + IMR, info->imra_value);
      } else {
            info->imrb_value &= ~mask;
            write_reg16(info, CHB + IMR, info->imrb_value);
      }
}

#define port_irq_disable(info, mask) \
  { info->pim_value |= (mask); write_reg(info, PIM, info->pim_value); }

#define port_irq_enable(info, mask) \
  { info->pim_value &= ~(mask); write_reg(info, PIM, info->pim_value); }

static void rx_start(MGSLPC_INFO *info);
static void rx_stop(MGSLPC_INFO *info);

static void tx_start(MGSLPC_INFO *info);
static void tx_stop(MGSLPC_INFO *info);
static void tx_set_idle(MGSLPC_INFO *info);

static void get_signals(MGSLPC_INFO *info);
static void set_signals(MGSLPC_INFO *info);

static void reset_device(MGSLPC_INFO *info);

static void hdlc_mode(MGSLPC_INFO *info);
static void async_mode(MGSLPC_INFO *info);

static void tx_timeout(unsigned long context);

static int ioctl_common(MGSLPC_INFO *info, unsigned int cmd, unsigned long arg);

#if SYNCLINK_GENERIC_HDLC
#define dev_to_port(D) (dev_to_hdlc(D)->priv)
static void hdlcdev_tx_done(MGSLPC_INFO *info);
static void hdlcdev_rx(MGSLPC_INFO *info, char *buf, int size);
static int  hdlcdev_init(MGSLPC_INFO *info);
static void hdlcdev_exit(MGSLPC_INFO *info);
#endif

static void trace_block(MGSLPC_INFO *info,const char* data, int count, int xmit);

static BOOLEAN register_test(MGSLPC_INFO *info);
static BOOLEAN irq_test(MGSLPC_INFO *info);
static int adapter_test(MGSLPC_INFO *info);

static int claim_resources(MGSLPC_INFO *info);
static void release_resources(MGSLPC_INFO *info);
static void mgslpc_add_device(MGSLPC_INFO *info);
static void mgslpc_remove_device(MGSLPC_INFO *info);

static int  rx_get_frame(MGSLPC_INFO *info);
static void rx_reset_buffers(MGSLPC_INFO *info);
static int  rx_alloc_buffers(MGSLPC_INFO *info);
static void rx_free_buffers(MGSLPC_INFO *info);

static irqreturn_t mgslpc_isr(int irq, void *dev_id);

/*
 * Bottom half interrupt handlers
 */
static void bh_handler(struct work_struct *work);
static void bh_transmit(MGSLPC_INFO *info);
static void bh_status(MGSLPC_INFO *info);

/*
 * ioctl handlers
 */
static int tiocmget(struct tty_struct *tty, struct file *file);
static int tiocmset(struct tty_struct *tty, struct file *file,
                unsigned int set, unsigned int clear);
static int get_stats(MGSLPC_INFO *info, struct mgsl_icount __user *user_icount);
static int get_params(MGSLPC_INFO *info, MGSL_PARAMS __user *user_params);
static int set_params(MGSLPC_INFO *info, MGSL_PARAMS __user *new_params);
static int get_txidle(MGSLPC_INFO *info, int __user *idle_mode);
static int set_txidle(MGSLPC_INFO *info, int idle_mode);
static int set_txenable(MGSLPC_INFO *info, int enable);
static int tx_abort(MGSLPC_INFO *info);
static int set_rxenable(MGSLPC_INFO *info, int enable);
static int wait_events(MGSLPC_INFO *info, int __user *mask);

static MGSLPC_INFO *mgslpc_device_list = NULL;
static int mgslpc_device_count = 0;

/*
 * Set this param to non-zero to load eax with the
 * .text section address and breakpoint on module load.
 * This is useful for use with gdb and add-symbol-file command.
 */
static int break_on_load=0;

/*
 * Driver major number, defaults to zero to get auto
 * assigned major number. May be forced as module parameter.
 */
static int ttymajor=0;

static int debug_level = 0;
static int maxframe[MAX_DEVICE_COUNT] = {0,};
static int dosyncppp[MAX_DEVICE_COUNT] = {1,1,1,1};

module_param(break_on_load, bool, 0);
module_param(ttymajor, int, 0);
module_param(debug_level, int, 0);
module_param_array(maxframe, int, NULL, 0);
module_param_array(dosyncppp, int, NULL, 0);

MODULE_LICENSE("GPL");

static char *driver_name = "SyncLink PC Card driver";
static char *driver_version = "$Revision: 4.34 $";

static struct tty_driver *serial_driver;

/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256

static void mgslpc_change_params(MGSLPC_INFO *info);
static void mgslpc_wait_until_sent(struct tty_struct *tty, int timeout);

/* PCMCIA prototypes */

static int mgslpc_config(struct pcmcia_device *link);
static void mgslpc_release(u_long arg);
static void mgslpc_detach(struct pcmcia_device *p_dev);

/*
 * 1st function defined in .text section. Calling this function in
 * init_module() followed by a breakpoint allows a remote debugger
 * (gdb) to get the .text address for the add-symbol-file command.
 * This allows remote debugging of dynamically loadable modules.
 */
static void* mgslpc_get_text_ptr(void)
{
      return mgslpc_get_text_ptr;
}

/**
 * line discipline callback wrappers
 *
 * The wrappers maintain line discipline references
 * while calling into the line discipline.
 *
 * ldisc_flush_buffer - flush line discipline receive buffers
 * ldisc_receive_buf  - pass receive data to line discipline
 */

static void ldisc_flush_buffer(struct tty_struct *tty)
{
      struct tty_ldisc *ld = tty_ldisc_ref(tty);
      if (ld) {
            if (ld->flush_buffer)
                  ld->flush_buffer(tty);
            tty_ldisc_deref(ld);
      }
}

static void ldisc_receive_buf(struct tty_struct *tty,
                        const __u8 *data, char *flags, int count)
{
      struct tty_ldisc *ld;
      if (!tty)
            return;
      ld = tty_ldisc_ref(tty);
      if (ld) {
            if (ld->receive_buf)
                  ld->receive_buf(tty, data, flags, count);
            tty_ldisc_deref(ld);
      }
}

static int mgslpc_probe(struct pcmcia_device *link)
{
    MGSLPC_INFO *info;
    int ret;

    if (debug_level >= DEBUG_LEVEL_INFO)
          printk("mgslpc_attach\n");

    info = kzalloc(sizeof(MGSLPC_INFO), GFP_KERNEL);
    if (!info) {
          printk("Error can't allocate device instance data\n");
          return -ENOMEM;
    }

    info->magic = MGSLPC_MAGIC;
    INIT_WORK(&info->task, bh_handler);
    info->max_frame_size = 4096;
    info->close_delay = 5*HZ/10;
    info->closing_wait = 30*HZ;
    init_waitqueue_head(&info->open_wait);
    init_waitqueue_head(&info->close_wait);
    init_waitqueue_head(&info->status_event_wait_q);
    init_waitqueue_head(&info->event_wait_q);
    spin_lock_init(&info->lock);
    spin_lock_init(&info->netlock);
    memcpy(&info->params,&default_params,sizeof(MGSL_PARAMS));
    info->idle_mode = HDLC_TXIDLE_FLAGS;
    info->imra_value = 0xffff;
    info->imrb_value = 0xffff;
    info->pim_value = 0xff;

    info->p_dev = link;
    link->priv = info;

    /* Initialize the struct pcmcia_device structure */

    /* Interrupt setup */
    link->irq.Attributes = IRQ_TYPE_EXCLUSIVE;
    link->irq.IRQInfo1   = IRQ_LEVEL_ID;
    link->irq.Handler = NULL;

    link->conf.Attributes = 0;
    link->conf.IntType = INT_MEMORY_AND_IO;

    ret = mgslpc_config(link);
    if (ret)
          return ret;

    mgslpc_add_device(info);

    return 0;
}

/* Card has been inserted.
 */

#define CS_CHECK(fn, ret) \
do { last_fn = (fn); if ((last_ret = (ret)) != 0) goto cs_failed; } while (0)

static int mgslpc_config(struct pcmcia_device *link)
{
    MGSLPC_INFO *info = link->priv;
    tuple_t tuple;
    cisparse_t parse;
    int last_fn, last_ret;
    u_char buf[64];
    cistpl_cftable_entry_t dflt = { 0 };
    cistpl_cftable_entry_t *cfg;

    if (debug_level >= DEBUG_LEVEL_INFO)
          printk("mgslpc_config(0x%p)\n", link);

    tuple.Attributes = 0;
    tuple.TupleData = buf;
    tuple.TupleDataMax = sizeof(buf);
    tuple.TupleOffset = 0;

    /* get CIS configuration entry */

    tuple.DesiredTuple = CISTPL_CFTABLE_ENTRY;
    CS_CHECK(GetFirstTuple, pcmcia_get_first_tuple(link, &tuple));

    cfg = &(parse.cftable_entry);
    CS_CHECK(GetTupleData, pcmcia_get_tuple_data(link, &tuple));
    CS_CHECK(ParseTuple, pcmcia_parse_tuple(link, &tuple, &parse));

    if (cfg->flags & CISTPL_CFTABLE_DEFAULT) dflt = *cfg;
    if (cfg->index == 0)
          goto cs_failed;

    link->conf.ConfigIndex = cfg->index;
    link->conf.Attributes |= CONF_ENABLE_IRQ;

    /* IO window settings */
    link->io.NumPorts1 = 0;
    if ((cfg->io.nwin > 0) || (dflt.io.nwin > 0)) {
          cistpl_io_t *io = (cfg->io.nwin) ? &cfg->io : &dflt.io;
          link->io.Attributes1 = IO_DATA_PATH_WIDTH_AUTO;
          if (!(io->flags & CISTPL_IO_8BIT))
                link->io.Attributes1 = IO_DATA_PATH_WIDTH_16;
          if (!(io->flags & CISTPL_IO_16BIT))
                link->io.Attributes1 = IO_DATA_PATH_WIDTH_8;
          link->io.IOAddrLines = io->flags & CISTPL_IO_LINES_MASK;
          link->io.BasePort1 = io->win[0].base;
          link->io.NumPorts1 = io->win[0].len;
          CS_CHECK(RequestIO, pcmcia_request_io(link, &link->io));
    }

    link->conf.Attributes = CONF_ENABLE_IRQ;
    link->conf.IntType = INT_MEMORY_AND_IO;
    link->conf.ConfigIndex = 8;
    link->conf.Present = PRESENT_OPTION;

    link->irq.Attributes |= IRQ_HANDLE_PRESENT;
    link->irq.Handler     = mgslpc_isr;
    link->irq.Instance    = info;
    CS_CHECK(RequestIRQ, pcmcia_request_irq(link, &link->irq));

    CS_CHECK(RequestConfiguration, pcmcia_request_configuration(link, &link->conf));

    info->io_base = link->io.BasePort1;
    info->irq_level = link->irq.AssignedIRQ;

    /* add to linked list of devices */
    sprintf(info->node.dev_name, "mgslpc0");
    info->node.major = info->node.minor = 0;
    link->dev_node = &info->node;

    printk(KERN_INFO "%s: index 0x%02x:",
         info->node.dev_name, link->conf.ConfigIndex);
    if (link->conf.Attributes & CONF_ENABLE_IRQ)
          printk(", irq %d", link->irq.AssignedIRQ);
    if (link->io.NumPorts1)
          printk(", io 0x%04x-0x%04x", link->io.BasePort1,
               link->io.BasePort1+link->io.NumPorts1-1);
    printk("\n");
    return 0;

cs_failed:
    cs_error(link, last_fn, last_ret);
    mgslpc_release((u_long)link);
    return -ENODEV;
}

/* Card has been removed.
 * Unregister device and release PCMCIA configuration.
 * If device is open, postpone until it is closed.
 */
static void mgslpc_release(u_long arg)
{
      struct pcmcia_device *link = (struct pcmcia_device *)arg;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("mgslpc_release(0x%p)\n", link);

      pcmcia_disable_device(link);
}

static void mgslpc_detach(struct pcmcia_device *link)
{
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("mgslpc_detach(0x%p)\n", link);

      ((MGSLPC_INFO *)link->priv)->stop = 1;
      mgslpc_release((u_long)link);

      mgslpc_remove_device((MGSLPC_INFO *)link->priv);
}

static int mgslpc_suspend(struct pcmcia_device *link)
{
      MGSLPC_INFO *info = link->priv;

      info->stop = 1;

      return 0;
}

static int mgslpc_resume(struct pcmcia_device *link)
{
      MGSLPC_INFO *info = link->priv;

      info->stop = 0;

      return 0;
}


static inline int mgslpc_paranoia_check(MGSLPC_INFO *info,
                              char *name, const char *routine)
{
#ifdef MGSLPC_PARANOIA_CHECK
      static const char *badmagic =
            "Warning: bad magic number for mgsl struct (%s) in %s\n";
      static const char *badinfo =
            "Warning: null mgslpc_info for (%s) in %s\n";

      if (!info) {
            printk(badinfo, name, routine);
            return 1;
      }
      if (info->magic != MGSLPC_MAGIC) {
            printk(badmagic, name, routine);
            return 1;
      }
#else
      if (!info)
            return 1;
#endif
      return 0;
}


#define CMD_RXFIFO      BIT7  // release current rx FIFO
#define CMD_RXRESET     BIT6  // receiver reset
#define CMD_RXFIFO_READ BIT5
#define CMD_START_TIMER BIT4
#define CMD_TXFIFO      BIT3  // release current tx FIFO
#define CMD_TXEOM       BIT1  // transmit end message
#define CMD_TXRESET     BIT0  // transmit reset

static BOOLEAN wait_command_complete(MGSLPC_INFO *info, unsigned char channel)
{
      int i = 0;
      /* wait for command completion */
      while (read_reg(info, (unsigned char)(channel+STAR)) & BIT2) {
            udelay(1);
            if (i++ == 1000)
                  return FALSE;
      }
      return TRUE;
}

static void issue_command(MGSLPC_INFO *info, unsigned char channel, unsigned char cmd)
{
      wait_command_complete(info, channel);
      write_reg(info, (unsigned char) (channel + CMDR), cmd);
}

static void tx_pause(struct tty_struct *tty)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (mgslpc_paranoia_check(info, tty->name, "tx_pause"))
            return;
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("tx_pause(%s)\n",info->device_name);

      spin_lock_irqsave(&info->lock,flags);
      if (info->tx_enabled)
            tx_stop(info);
      spin_unlock_irqrestore(&info->lock,flags);
}

static void tx_release(struct tty_struct *tty)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (mgslpc_paranoia_check(info, tty->name, "tx_release"))
            return;
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("tx_release(%s)\n",info->device_name);

      spin_lock_irqsave(&info->lock,flags);
      if (!info->tx_enabled)
            tx_start(info);
      spin_unlock_irqrestore(&info->lock,flags);
}

/* Return next bottom half action to perform.
 * or 0 if nothing to do.
 */
static int bh_action(MGSLPC_INFO *info)
{
      unsigned long flags;
      int rc = 0;

      spin_lock_irqsave(&info->lock,flags);

      if (info->pending_bh & BH_RECEIVE) {
            info->pending_bh &= ~BH_RECEIVE;
            rc = BH_RECEIVE;
      } else if (info->pending_bh & BH_TRANSMIT) {
            info->pending_bh &= ~BH_TRANSMIT;
            rc = BH_TRANSMIT;
      } else if (info->pending_bh & BH_STATUS) {
            info->pending_bh &= ~BH_STATUS;
            rc = BH_STATUS;
      }

      if (!rc) {
            /* Mark BH routine as complete */
            info->bh_running   = 0;
            info->bh_requested = 0;
      }

      spin_unlock_irqrestore(&info->lock,flags);

      return rc;
}

static void bh_handler(struct work_struct *work)
{
      MGSLPC_INFO *info = container_of(work, MGSLPC_INFO, task);
      int action;

      if (!info)
            return;

      if (debug_level >= DEBUG_LEVEL_BH)
            printk( "%s(%d):bh_handler(%s) entry\n",
                  __FILE__,__LINE__,info->device_name);

      info->bh_running = 1;

      while((action = bh_action(info)) != 0) {

            /* Process work item */
            if ( debug_level >= DEBUG_LEVEL_BH )
                  printk( "%s(%d):bh_handler() work item action=%d\n",
                        __FILE__,__LINE__,action);

            switch (action) {

            case BH_RECEIVE:
                  while(rx_get_frame(info));
                  break;
            case BH_TRANSMIT:
                  bh_transmit(info);
                  break;
            case BH_STATUS:
                  bh_status(info);
                  break;
            default:
                  /* unknown work item ID */
                  printk("Unknown work item ID=%08X!\n", action);
                  break;
            }
      }

      if (debug_level >= DEBUG_LEVEL_BH)
            printk( "%s(%d):bh_handler(%s) exit\n",
                  __FILE__,__LINE__,info->device_name);
}

static void bh_transmit(MGSLPC_INFO *info)
{
      struct tty_struct *tty = info->tty;
      if (debug_level >= DEBUG_LEVEL_BH)
            printk("bh_transmit() entry on %s\n", info->device_name);

      if (tty)
            tty_wakeup(tty);
}

static void bh_status(MGSLPC_INFO *info)
{
      info->ri_chkcount = 0;
      info->dsr_chkcount = 0;
      info->dcd_chkcount = 0;
      info->cts_chkcount = 0;
}

/* eom: non-zero = end of frame */
static void rx_ready_hdlc(MGSLPC_INFO *info, int eom)
{
      unsigned char data[2];
      unsigned char fifo_count, read_count, i;
      RXBUF *buf = (RXBUF*)(info->rx_buf + (info->rx_put * info->rx_buf_size));

      if (debug_level >= DEBUG_LEVEL_ISR)
            printk("%s(%d):rx_ready_hdlc(eom=%d)\n",__FILE__,__LINE__,eom);

      if (!info->rx_enabled)
            return;

      if (info->rx_frame_count >= info->rx_buf_count) {
            /* no more free buffers */
            issue_command(info, CHA, CMD_RXRESET);
            info->pending_bh |= BH_RECEIVE;
            info->rx_overflow = 1;
            info->icount.buf_overrun++;
            return;
      }

      if (eom) {
            /* end of frame, get FIFO count from RBCL register */
            if (!(fifo_count = (unsigned char)(read_reg(info, CHA+RBCL) & 0x1f)))
                  fifo_count = 32;
      } else
            fifo_count = 32;

      do {
            if (fifo_count == 1) {
                  read_count = 1;
                  data[0] = read_reg(info, CHA + RXFIFO);
            } else {
                  read_count = 2;
                  *((unsigned short *) data) = read_reg16(info, CHA + RXFIFO);
            }
            fifo_count -= read_count;
            if (!fifo_count && eom)
                  buf->status = data[--read_count];

            for (i = 0; i < read_count; i++) {
                  if (buf->count >= info->max_frame_size) {
                        /* frame too large, reset receiver and reset current buffer */
                        issue_command(info, CHA, CMD_RXRESET);
                        buf->count = 0;
                        return;
                  }
                  *(buf->data + buf->count) = data[i];
                  buf->count++;
            }
      } while (fifo_count);

      if (eom) {
            info->pending_bh |= BH_RECEIVE;
            info->rx_frame_count++;
            info->rx_put++;
            if (info->rx_put >= info->rx_buf_count)
                  info->rx_put = 0;
      }
      issue_command(info, CHA, CMD_RXFIFO);
}

static void rx_ready_async(MGSLPC_INFO *info, int tcd)
{
      unsigned char data, status, flag;
      int fifo_count;
      int work = 0;
      struct tty_struct *tty = info->tty;
      struct mgsl_icount *icount = &info->icount;

      if (tcd) {
            /* early termination, get FIFO count from RBCL register */
            fifo_count = (unsigned char)(read_reg(info, CHA+RBCL) & 0x1f);

            /* Zero fifo count could mean 0 or 32 bytes available.
             * If BIT5 of STAR is set then at least 1 byte is available.
             */
            if (!fifo_count && (read_reg(info,CHA+STAR) & BIT5))
                  fifo_count = 32;
      } else
            fifo_count = 32;

      tty_buffer_request_room(tty, fifo_count);
      /* Flush received async data to receive data buffer. */
      while (fifo_count) {
            data   = read_reg(info, CHA + RXFIFO);
            status = read_reg(info, CHA + RXFIFO);
            fifo_count -= 2;

            icount->rx++;
            flag = TTY_NORMAL;

            // if no frameing/crc error then save data
            // BIT7:parity error
            // BIT6:framing error

            if (status & (BIT7 + BIT6)) {
                  if (status & BIT7)
                        icount->parity++;
                  else
                        icount->frame++;

                  /* discard char if tty control flags say so */
                  if (status & info->ignore_status_mask)
                        continue;

                  status &= info->read_status_mask;

                  if (status & BIT7)
                        flag = TTY_PARITY;
                  else if (status & BIT6)
                        flag = TTY_FRAME;
            }
            work += tty_insert_flip_char(tty, data, flag);
      }
      issue_command(info, CHA, CMD_RXFIFO);

      if (debug_level >= DEBUG_LEVEL_ISR) {
            printk("%s(%d):rx_ready_async",
                  __FILE__,__LINE__);
            printk("%s(%d):rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
                  __FILE__,__LINE__,icount->rx,icount->brk,
                  icount->parity,icount->frame,icount->overrun);
      }

      if (work)
            tty_flip_buffer_push(tty);
}


static void tx_done(MGSLPC_INFO *info)
{
      if (!info->tx_active)
            return;

      info->tx_active = 0;
      info->tx_aborting = 0;

      if (info->params.mode == MGSL_MODE_ASYNC)
            return;

      info->tx_count = info->tx_put = info->tx_get = 0;
      del_timer(&info->tx_timer);

      if (info->drop_rts_on_tx_done) {
            get_signals(info);
            if (info->serial_signals & SerialSignal_RTS) {
                  info->serial_signals &= ~SerialSignal_RTS;
                  set_signals(info);
            }
            info->drop_rts_on_tx_done = 0;
      }

#if SYNCLINK_GENERIC_HDLC
      if (info->netcount)
            hdlcdev_tx_done(info);
      else
#endif
      {
            if (info->tty->stopped || info->tty->hw_stopped) {
                  tx_stop(info);
                  return;
            }
            info->pending_bh |= BH_TRANSMIT;
      }
}

static void tx_ready(MGSLPC_INFO *info)
{
      unsigned char fifo_count = 32;
      int c;

      if (debug_level >= DEBUG_LEVEL_ISR)
            printk("%s(%d):tx_ready(%s)\n", __FILE__,__LINE__,info->device_name);

      if (info->params.mode == MGSL_MODE_HDLC) {
            if (!info->tx_active)
                  return;
      } else {
            if (info->tty->stopped || info->tty->hw_stopped) {
                  tx_stop(info);
                  return;
            }
            if (!info->tx_count)
                  info->tx_active = 0;
      }

      if (!info->tx_count)
            return;

      while (info->tx_count && fifo_count) {
            c = min(2, min_t(int, fifo_count, min(info->tx_count, TXBUFSIZE - info->tx_get)));

            if (c == 1) {
                  write_reg(info, CHA + TXFIFO, *(info->tx_buf + info->tx_get));
            } else {
                  write_reg16(info, CHA + TXFIFO,
                                *((unsigned short*)(info->tx_buf + info->tx_get)));
            }
            info->tx_count -= c;
            info->tx_get = (info->tx_get + c) & (TXBUFSIZE - 1);
            fifo_count -= c;
      }

      if (info->params.mode == MGSL_MODE_ASYNC) {
            if (info->tx_count < WAKEUP_CHARS)
                  info->pending_bh |= BH_TRANSMIT;
            issue_command(info, CHA, CMD_TXFIFO);
      } else {
            if (info->tx_count)
                  issue_command(info, CHA, CMD_TXFIFO);
            else
                  issue_command(info, CHA, CMD_TXFIFO + CMD_TXEOM);
      }
}

static void cts_change(MGSLPC_INFO *info)
{
      get_signals(info);
      if ((info->cts_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
            irq_disable(info, CHB, IRQ_CTS);
      info->icount.cts++;
      if (info->serial_signals & SerialSignal_CTS)
            info->input_signal_events.cts_up++;
      else
            info->input_signal_events.cts_down++;
      wake_up_interruptible(&info->status_event_wait_q);
      wake_up_interruptible(&info->event_wait_q);

      if (info->flags & ASYNC_CTS_FLOW) {
            if (info->tty->hw_stopped) {
                  if (info->serial_signals & SerialSignal_CTS) {
                        if (debug_level >= DEBUG_LEVEL_ISR)
                              printk("CTS tx start...");
                        if (info->tty)
                              info->tty->hw_stopped = 0;
                        tx_start(info);
                        info->pending_bh |= BH_TRANSMIT;
                        return;
                  }
            } else {
                  if (!(info->serial_signals & SerialSignal_CTS)) {
                        if (debug_level >= DEBUG_LEVEL_ISR)
                              printk("CTS tx stop...");
                        if (info->tty)
                              info->tty->hw_stopped = 1;
                        tx_stop(info);
                  }
            }
      }
      info->pending_bh |= BH_STATUS;
}

static void dcd_change(MGSLPC_INFO *info)
{
      get_signals(info);
      if ((info->dcd_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
            irq_disable(info, CHB, IRQ_DCD);
      info->icount.dcd++;
      if (info->serial_signals & SerialSignal_DCD) {
            info->input_signal_events.dcd_up++;
      }
      else
            info->input_signal_events.dcd_down++;
#if SYNCLINK_GENERIC_HDLC
      if (info->netcount) {
            if (info->serial_signals & SerialSignal_DCD)
                  netif_carrier_on(info->netdev);
            else
                  netif_carrier_off(info->netdev);
      }
#endif
      wake_up_interruptible(&info->status_event_wait_q);
      wake_up_interruptible(&info->event_wait_q);

      if (info->flags & ASYNC_CHECK_CD) {
            if (debug_level >= DEBUG_LEVEL_ISR)
                  printk("%s CD now %s...", info->device_name,
                         (info->serial_signals & SerialSignal_DCD) ? "on" : "off");
            if (info->serial_signals & SerialSignal_DCD)
                  wake_up_interruptible(&info->open_wait);
            else {
                  if (debug_level >= DEBUG_LEVEL_ISR)
                        printk("doing serial hangup...");
                  if (info->tty)
                        tty_hangup(info->tty);
            }
      }
      info->pending_bh |= BH_STATUS;
}

static void dsr_change(MGSLPC_INFO *info)
{
      get_signals(info);
      if ((info->dsr_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
            port_irq_disable(info, PVR_DSR);
      info->icount.dsr++;
      if (info->serial_signals & SerialSignal_DSR)
            info->input_signal_events.dsr_up++;
      else
            info->input_signal_events.dsr_down++;
      wake_up_interruptible(&info->status_event_wait_q);
      wake_up_interruptible(&info->event_wait_q);
      info->pending_bh |= BH_STATUS;
}

static void ri_change(MGSLPC_INFO *info)
{
      get_signals(info);
      if ((info->ri_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
            port_irq_disable(info, PVR_RI);
      info->icount.rng++;
      if (info->serial_signals & SerialSignal_RI)
            info->input_signal_events.ri_up++;
      else
            info->input_signal_events.ri_down++;
      wake_up_interruptible(&info->status_event_wait_q);
      wake_up_interruptible(&info->event_wait_q);
      info->pending_bh |= BH_STATUS;
}

/* Interrupt service routine entry point.
 *
 * Arguments:
 *
 * irq     interrupt number that caused interrupt
 * dev_id  device ID supplied during interrupt registration
 */
static irqreturn_t mgslpc_isr(int irq, void *dev_id)
{
      MGSLPC_INFO * info = (MGSLPC_INFO *)dev_id;
      unsigned short isr;
      unsigned char gis, pis;
      int count=0;

      if (debug_level >= DEBUG_LEVEL_ISR)
            printk("mgslpc_isr(%d) entry.\n", irq);
      if (!info)
            return IRQ_NONE;

      if (!(info->p_dev->_locked))
            return IRQ_HANDLED;

      spin_lock(&info->lock);

      while ((gis = read_reg(info, CHA + GIS))) {
            if (debug_level >= DEBUG_LEVEL_ISR)
                  printk("mgslpc_isr %s gis=%04X\n", info->device_name,gis);

            if ((gis & 0x70) || count > 1000) {
                  printk("synclink_cs:hardware failed or ejected\n");
                  break;
            }
            count++;

            if (gis & (BIT1 + BIT0)) {
                  isr = read_reg16(info, CHB + ISR);
                  if (isr & IRQ_DCD)
                        dcd_change(info);
                  if (isr & IRQ_CTS)
                        cts_change(info);
            }
            if (gis & (BIT3 + BIT2))
            {
                  isr = read_reg16(info, CHA + ISR);
                  if (isr & IRQ_TIMER) {
                        info->irq_occurred = 1;
                        irq_disable(info, CHA, IRQ_TIMER);
                  }

                  /* receive IRQs */
                  if (isr & IRQ_EXITHUNT) {
                        info->icount.exithunt++;
                        wake_up_interruptible(&info->event_wait_q);
                  }
                  if (isr & IRQ_BREAK_ON) {
                        info->icount.brk++;
                        if (info->flags & ASYNC_SAK)
                              do_SAK(info->tty);
                  }
                  if (isr & IRQ_RXTIME) {
                        issue_command(info, CHA, CMD_RXFIFO_READ);
                  }
                  if (isr & (IRQ_RXEOM + IRQ_RXFIFO)) {
                        if (info->params.mode == MGSL_MODE_HDLC)
                              rx_ready_hdlc(info, isr & IRQ_RXEOM);
                        else
                              rx_ready_async(info, isr & IRQ_RXEOM);
                  }

                  /* transmit IRQs */
                  if (isr & IRQ_UNDERRUN) {
                        if (info->tx_aborting)
                              info->icount.txabort++;
                        else
                              info->icount.txunder++;
                        tx_done(info);
                  }
                  else if (isr & IRQ_ALLSENT) {
                        info->icount.txok++;
                        tx_done(info);
                  }
                  else if (isr & IRQ_TXFIFO)
                        tx_ready(info);
            }
            if (gis & BIT7) {
                  pis = read_reg(info, CHA + PIS);
                  if (pis & BIT1)
                        dsr_change(info);
                  if (pis & BIT2)
                        ri_change(info);
            }
      }

      /* Request bottom half processing if there's something
       * for it to do and the bh is not already running
       */

      if (info->pending_bh && !info->bh_running && !info->bh_requested) {
            if ( debug_level >= DEBUG_LEVEL_ISR )
                  printk("%s(%d):%s queueing bh task.\n",
                        __FILE__,__LINE__,info->device_name);
            schedule_work(&info->task);
            info->bh_requested = 1;
      }

      spin_unlock(&info->lock);

      if (debug_level >= DEBUG_LEVEL_ISR)
            printk("%s(%d):mgslpc_isr(%d)exit.\n",
                   __FILE__,__LINE__,irq);

      return IRQ_HANDLED;
}

/* Initialize and start device.
 */
static int startup(MGSLPC_INFO * info)
{
      int retval = 0;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):startup(%s)\n",__FILE__,__LINE__,info->device_name);

      if (info->flags & ASYNC_INITIALIZED)
            return 0;

      if (!info->tx_buf) {
            /* allocate a page of memory for a transmit buffer */
            info->tx_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
            if (!info->tx_buf) {
                  printk(KERN_ERR"%s(%d):%s can't allocate transmit buffer\n",
                        __FILE__,__LINE__,info->device_name);
                  return -ENOMEM;
            }
      }

      info->pending_bh = 0;

      memset(&info->icount, 0, sizeof(info->icount));

      setup_timer(&info->tx_timer, tx_timeout, (unsigned long)info);

      /* Allocate and claim adapter resources */
      retval = claim_resources(info);

      /* perform existance check and diagnostics */
      if ( !retval )
            retval = adapter_test(info);

      if ( retval ) {
            if (capable(CAP_SYS_ADMIN) && info->tty)
                  set_bit(TTY_IO_ERROR, &info->tty->flags);
            release_resources(info);
            return retval;
      }

      /* program hardware for current parameters */
      mgslpc_change_params(info);

      if (info->tty)
            clear_bit(TTY_IO_ERROR, &info->tty->flags);

      info->flags |= ASYNC_INITIALIZED;

      return 0;
}

/* Called by mgslpc_close() and mgslpc_hangup() to shutdown hardware
 */
static void shutdown(MGSLPC_INFO * info)
{
      unsigned long flags;

      if (!(info->flags & ASYNC_INITIALIZED))
            return;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_shutdown(%s)\n",
                   __FILE__,__LINE__, info->device_name );

      /* clear status wait queue because status changes */
      /* can't happen after shutting down the hardware */
      wake_up_interruptible(&info->status_event_wait_q);
      wake_up_interruptible(&info->event_wait_q);

      del_timer_sync(&info->tx_timer);

      if (info->tx_buf) {
            free_page((unsigned long) info->tx_buf);
            info->tx_buf = NULL;
      }

      spin_lock_irqsave(&info->lock,flags);

      rx_stop(info);
      tx_stop(info);

      /* TODO:disable interrupts instead of reset to preserve signal states */
      reset_device(info);

      if (!info->tty || info->tty->termios->c_cflag & HUPCL) {
            info->serial_signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
            set_signals(info);
      }

      spin_unlock_irqrestore(&info->lock,flags);

      release_resources(info);

      if (info->tty)
            set_bit(TTY_IO_ERROR, &info->tty->flags);

      info->flags &= ~ASYNC_INITIALIZED;
}

static void mgslpc_program_hw(MGSLPC_INFO *info)
{
      unsigned long flags;

      spin_lock_irqsave(&info->lock,flags);

      rx_stop(info);
      tx_stop(info);
      info->tx_count = info->tx_put = info->tx_get = 0;

      if (info->params.mode == MGSL_MODE_HDLC || info->netcount)
            hdlc_mode(info);
      else
            async_mode(info);

      set_signals(info);

      info->dcd_chkcount = 0;
      info->cts_chkcount = 0;
      info->ri_chkcount = 0;
      info->dsr_chkcount = 0;

      irq_enable(info, CHB, IRQ_DCD | IRQ_CTS);
      port_irq_enable(info, (unsigned char) PVR_DSR | PVR_RI);
      get_signals(info);

      if (info->netcount || info->tty->termios->c_cflag & CREAD)
            rx_start(info);

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

/* Reconfigure adapter based on new parameters
 */
static void mgslpc_change_params(MGSLPC_INFO *info)
{
      unsigned cflag;
      int bits_per_char;

      if (!info->tty || !info->tty->termios)
            return;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_change_params(%s)\n",
                   __FILE__,__LINE__, info->device_name );

      cflag = info->tty->termios->c_cflag;

      /* if B0 rate (hangup) specified then negate DTR and RTS */
      /* otherwise assert DTR and RTS */
      if (cflag & CBAUD)
            info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
      else
            info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);

      /* byte size and parity */

      switch (cflag & CSIZE) {
      case CS5: info->params.data_bits = 5; break;
      case CS6: info->params.data_bits = 6; break;
      case CS7: info->params.data_bits = 7; break;
      case CS8: info->params.data_bits = 8; break;
      default:  info->params.data_bits = 7; break;
      }

      if (cflag & CSTOPB)
            info->params.stop_bits = 2;
      else
            info->params.stop_bits = 1;

      info->params.parity = ASYNC_PARITY_NONE;
      if (cflag & PARENB) {
            if (cflag & PARODD)
                  info->params.parity = ASYNC_PARITY_ODD;
            else
                  info->params.parity = ASYNC_PARITY_EVEN;
#ifdef CMSPAR
            if (cflag & CMSPAR)
                  info->params.parity = ASYNC_PARITY_SPACE;
#endif
      }

      /* calculate number of jiffies to transmit a full
       * FIFO (32 bytes) at specified data rate
       */
      bits_per_char = info->params.data_bits +
                  info->params.stop_bits + 1;

      /* if port data rate is set to 460800 or less then
       * allow tty settings to override, otherwise keep the
       * current data rate.
       */
      if (info->params.data_rate <= 460800) {
            info->params.data_rate = tty_get_baud_rate(info->tty);
      }

      if ( info->params.data_rate ) {
            info->timeout = (32*HZ*bits_per_char) /
                        info->params.data_rate;
      }
      info->timeout += HZ/50;       /* Add .02 seconds of slop */

      if (cflag & CRTSCTS)
            info->flags |= ASYNC_CTS_FLOW;
      else
            info->flags &= ~ASYNC_CTS_FLOW;

      if (cflag & CLOCAL)
            info->flags &= ~ASYNC_CHECK_CD;
      else
            info->flags |= ASYNC_CHECK_CD;

      /* process tty input control flags */

      info->read_status_mask = 0;
      if (I_INPCK(info->tty))
            info->read_status_mask |= BIT7 | BIT6;
      if (I_IGNPAR(info->tty))
            info->ignore_status_mask |= BIT7 | BIT6;

      mgslpc_program_hw(info);
}

/* Add a character to the transmit buffer
 */
static void mgslpc_put_char(struct tty_struct *tty, unsigned char ch)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO) {
            printk( "%s(%d):mgslpc_put_char(%d) on %s\n",
                  __FILE__,__LINE__,ch,info->device_name);
      }

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_put_char"))
            return;

      if (!info->tx_buf)
            return;

      spin_lock_irqsave(&info->lock,flags);

      if (info->params.mode == MGSL_MODE_ASYNC || !info->tx_active) {
            if (info->tx_count < TXBUFSIZE - 1) {
                  info->tx_buf[info->tx_put++] = ch;
                  info->tx_put &= TXBUFSIZE-1;
                  info->tx_count++;
            }
      }

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

/* Enable transmitter so remaining characters in the
 * transmit buffer are sent.
 */
static void mgslpc_flush_chars(struct tty_struct *tty)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk( "%s(%d):mgslpc_flush_chars() entry on %s tx_count=%d\n",
                  __FILE__,__LINE__,info->device_name,info->tx_count);

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_flush_chars"))
            return;

      if (info->tx_count <= 0 || tty->stopped ||
          tty->hw_stopped || !info->tx_buf)
            return;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk( "%s(%d):mgslpc_flush_chars() entry on %s starting transmitter\n",
                  __FILE__,__LINE__,info->device_name);

      spin_lock_irqsave(&info->lock,flags);
      if (!info->tx_active)
            tx_start(info);
      spin_unlock_irqrestore(&info->lock,flags);
}

/* Send a block of data
 *
 * Arguments:
 *
 * tty        pointer to tty information structure
 * buf            pointer to buffer containing send data
 * count      size of send data in bytes
 *
 * Returns: number of characters written
 */
static int mgslpc_write(struct tty_struct * tty,
                  const unsigned char *buf, int count)
{
      int c, ret = 0;
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk( "%s(%d):mgslpc_write(%s) count=%d\n",
                  __FILE__,__LINE__,info->device_name,count);

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_write") ||
            !info->tx_buf)
            goto cleanup;

      if (info->params.mode == MGSL_MODE_HDLC) {
            if (count > TXBUFSIZE) {
                  ret = -EIO;
                  goto cleanup;
            }
            if (info->tx_active)
                  goto cleanup;
            else if (info->tx_count)
                  goto start;
      }

      for (;;) {
            c = min(count,
                  min(TXBUFSIZE - info->tx_count - 1,
                      TXBUFSIZE - info->tx_put));
            if (c <= 0)
                  break;

            memcpy(info->tx_buf + info->tx_put, buf, c);

            spin_lock_irqsave(&info->lock,flags);
            info->tx_put = (info->tx_put + c) & (TXBUFSIZE-1);
            info->tx_count += c;
            spin_unlock_irqrestore(&info->lock,flags);

            buf += c;
            count -= c;
            ret += c;
      }
start:
      if (info->tx_count && !tty->stopped && !tty->hw_stopped) {
            spin_lock_irqsave(&info->lock,flags);
            if (!info->tx_active)
                  tx_start(info);
            spin_unlock_irqrestore(&info->lock,flags);
      }
cleanup:
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk( "%s(%d):mgslpc_write(%s) returning=%d\n",
                  __FILE__,__LINE__,info->device_name,ret);
      return ret;
}

/* Return the count of free bytes in transmit buffer
 */
static int mgslpc_write_room(struct tty_struct *tty)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      int ret;

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_write_room"))
            return 0;

      if (info->params.mode == MGSL_MODE_HDLC) {
            /* HDLC (frame oriented) mode */
            if (info->tx_active)
                  return 0;
            else
                  return HDLC_MAX_FRAME_SIZE;
      } else {
            ret = TXBUFSIZE - info->tx_count - 1;
            if (ret < 0)
                  ret = 0;
      }

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_write_room(%s)=%d\n",
                   __FILE__,__LINE__, info->device_name, ret);
      return ret;
}

/* Return the count of bytes in transmit buffer
 */
static int mgslpc_chars_in_buffer(struct tty_struct *tty)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      int rc;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_chars_in_buffer(%s)\n",
                   __FILE__,__LINE__, info->device_name );

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_chars_in_buffer"))
            return 0;

      if (info->params.mode == MGSL_MODE_HDLC)
            rc = info->tx_active ? info->max_frame_size : 0;
      else
            rc = info->tx_count;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_chars_in_buffer(%s)=%d\n",
                   __FILE__,__LINE__, info->device_name, rc);

      return rc;
}

/* Discard all data in the send buffer
 */
static void mgslpc_flush_buffer(struct tty_struct *tty)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_flush_buffer(%s) entry\n",
                   __FILE__,__LINE__, info->device_name );

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_flush_buffer"))
            return;

      spin_lock_irqsave(&info->lock,flags);
      info->tx_count = info->tx_put = info->tx_get = 0;
      del_timer(&info->tx_timer);
      spin_unlock_irqrestore(&info->lock,flags);

      wake_up_interruptible(&tty->write_wait);
      tty_wakeup(tty);
}

/* Send a high-priority XON/XOFF character
 */
static void mgslpc_send_xchar(struct tty_struct *tty, char ch)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_send_xchar(%s,%d)\n",
                   __FILE__,__LINE__, info->device_name, ch );

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_send_xchar"))
            return;

      info->x_char = ch;
      if (ch) {
            spin_lock_irqsave(&info->lock,flags);
            if (!info->tx_enabled)
                  tx_start(info);
            spin_unlock_irqrestore(&info->lock,flags);
      }
}

/* Signal remote device to throttle send data (our receive data)
 */
static void mgslpc_throttle(struct tty_struct * tty)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_throttle(%s) entry\n",
                   __FILE__,__LINE__, info->device_name );

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_throttle"))
            return;

      if (I_IXOFF(tty))
            mgslpc_send_xchar(tty, STOP_CHAR(tty));

      if (tty->termios->c_cflag & CRTSCTS) {
            spin_lock_irqsave(&info->lock,flags);
            info->serial_signals &= ~SerialSignal_RTS;
            set_signals(info);
            spin_unlock_irqrestore(&info->lock,flags);
      }
}

/* Signal remote device to stop throttling send data (our receive data)
 */
static void mgslpc_unthrottle(struct tty_struct * tty)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_unthrottle(%s) entry\n",
                   __FILE__,__LINE__, info->device_name );

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_unthrottle"))
            return;

      if (I_IXOFF(tty)) {
            if (info->x_char)
                  info->x_char = 0;
            else
                  mgslpc_send_xchar(tty, START_CHAR(tty));
      }

      if (tty->termios->c_cflag & CRTSCTS) {
            spin_lock_irqsave(&info->lock,flags);
            info->serial_signals |= SerialSignal_RTS;
            set_signals(info);
            spin_unlock_irqrestore(&info->lock,flags);
      }
}

/* get the current serial statistics
 */
static int get_stats(MGSLPC_INFO * info, struct mgsl_icount __user *user_icount)
{
      int err;
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("get_params(%s)\n", info->device_name);
      if (!user_icount) {
            memset(&info->icount, 0, sizeof(info->icount));
      } else {
            COPY_TO_USER(err, user_icount, &info->icount, sizeof(struct mgsl_icount));
            if (err)
                  return -EFAULT;
      }
      return 0;
}

/* get the current serial parameters
 */
static int get_params(MGSLPC_INFO * info, MGSL_PARAMS __user *user_params)
{
      int err;
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("get_params(%s)\n", info->device_name);
      COPY_TO_USER(err,user_params, &info->params, sizeof(MGSL_PARAMS));
      if (err)
            return -EFAULT;
      return 0;
}

/* set the serial parameters
 *
 * Arguments:
 *
 *    info        pointer to device instance data
 *    new_params  user buffer containing new serial params
 *
 * Returns: 0 if success, otherwise error code
 */
static int set_params(MGSLPC_INFO * info, MGSL_PARAMS __user *new_params)
{
      unsigned long flags;
      MGSL_PARAMS tmp_params;
      int err;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):set_params %s\n", __FILE__,__LINE__,
                  info->device_name );
      COPY_FROM_USER(err,&tmp_params, new_params, sizeof(MGSL_PARAMS));
      if (err) {
            if ( debug_level >= DEBUG_LEVEL_INFO )
                  printk( "%s(%d):set_params(%s) user buffer copy failed\n",
                        __FILE__,__LINE__,info->device_name);
            return -EFAULT;
      }

      spin_lock_irqsave(&info->lock,flags);
      memcpy(&info->params,&tmp_params,sizeof(MGSL_PARAMS));
      spin_unlock_irqrestore(&info->lock,flags);

      mgslpc_change_params(info);

      return 0;
}

static int get_txidle(MGSLPC_INFO * info, int __user *idle_mode)
{
      int err;
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("get_txidle(%s)=%d\n", info->device_name, info->idle_mode);
      COPY_TO_USER(err,idle_mode, &info->idle_mode, sizeof(int));
      if (err)
            return -EFAULT;
      return 0;
}

static int set_txidle(MGSLPC_INFO * info, int idle_mode)
{
      unsigned long flags;
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("set_txidle(%s,%d)\n", info->device_name, idle_mode);
      spin_lock_irqsave(&info->lock,flags);
      info->idle_mode = idle_mode;
      tx_set_idle(info);
      spin_unlock_irqrestore(&info->lock,flags);
      return 0;
}

static int get_interface(MGSLPC_INFO * info, int __user *if_mode)
{
      int err;
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("get_interface(%s)=%d\n", info->device_name, info->if_mode);
      COPY_TO_USER(err,if_mode, &info->if_mode, sizeof(int));
      if (err)
            return -EFAULT;
      return 0;
}

static int set_interface(MGSLPC_INFO * info, int if_mode)
{
      unsigned long flags;
      unsigned char val;
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("set_interface(%s,%d)\n", info->device_name, if_mode);
      spin_lock_irqsave(&info->lock,flags);
      info->if_mode = if_mode;

      val = read_reg(info, PVR) & 0x0f;
      switch (info->if_mode)
      {
      case MGSL_INTERFACE_RS232: val |= PVR_RS232; break;
      case MGSL_INTERFACE_V35:   val |= PVR_V35;   break;
      case MGSL_INTERFACE_RS422: val |= PVR_RS422; break;
      }
      write_reg(info, PVR, val);

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

static int set_txenable(MGSLPC_INFO * info, int enable)
{
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("set_txenable(%s,%d)\n", info->device_name, enable);

      spin_lock_irqsave(&info->lock,flags);
      if (enable) {
            if (!info->tx_enabled)
                  tx_start(info);
      } else {
            if (info->tx_enabled)
                  tx_stop(info);
      }
      spin_unlock_irqrestore(&info->lock,flags);
      return 0;
}

static int tx_abort(MGSLPC_INFO * info)
{
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("tx_abort(%s)\n", info->device_name);

      spin_lock_irqsave(&info->lock,flags);
      if (info->tx_active && info->tx_count &&
          info->params.mode == MGSL_MODE_HDLC) {
            /* clear data count so FIFO is not filled on next IRQ.
             * This results in underrun and abort transmission.
             */
            info->tx_count = info->tx_put = info->tx_get = 0;
            info->tx_aborting = TRUE;
      }
      spin_unlock_irqrestore(&info->lock,flags);
      return 0;
}

static int set_rxenable(MGSLPC_INFO * info, int enable)
{
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("set_rxenable(%s,%d)\n", info->device_name, enable);

      spin_lock_irqsave(&info->lock,flags);
      if (enable) {
            if (!info->rx_enabled)
                  rx_start(info);
      } else {
            if (info->rx_enabled)
                  rx_stop(info);
      }
      spin_unlock_irqrestore(&info->lock,flags);
      return 0;
}

/* wait for specified event to occur
 *
 * Arguments:           info  pointer to device instance data
 *                mask  pointer to bitmask of events to wait for
 * Return Value:  0     if successful and bit mask updated with
 *                      of events triggerred,
 *                otherwise error code
 */
static int wait_events(MGSLPC_INFO * info, int __user *mask_ptr)
{
      unsigned long flags;
      int s;
      int rc=0;
      struct mgsl_icount cprev, cnow;
      int events;
      int mask;
      struct      _input_signal_events oldsigs, newsigs;
      DECLARE_WAITQUEUE(wait, current);

      COPY_FROM_USER(rc,&mask, mask_ptr, sizeof(int));
      if (rc)
            return  -EFAULT;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("wait_events(%s,%d)\n", info->device_name, mask);

      spin_lock_irqsave(&info->lock,flags);

      /* return immediately if state matches requested events */
      get_signals(info);
      s = info->serial_signals;
      events = mask &
            ( ((s & SerialSignal_DSR) ? MgslEvent_DsrActive:MgslEvent_DsrInactive) +
              ((s & SerialSignal_DCD) ? MgslEvent_DcdActive:MgslEvent_DcdInactive) +
              ((s & SerialSignal_CTS) ? MgslEvent_CtsActive:MgslEvent_CtsInactive) +
              ((s & SerialSignal_RI)  ? MgslEvent_RiActive :MgslEvent_RiInactive) );
      if (events) {
            spin_unlock_irqrestore(&info->lock,flags);
            goto exit;
      }

      /* save current irq counts */
      cprev = info->icount;
      oldsigs = info->input_signal_events;

      if ((info->params.mode == MGSL_MODE_HDLC) &&
          (mask & MgslEvent_ExitHuntMode))
            irq_enable(info, CHA, IRQ_EXITHUNT);

      set_current_state(TASK_INTERRUPTIBLE);
      add_wait_queue(&info->event_wait_q, &wait);

      spin_unlock_irqrestore(&info->lock,flags);


      for(;;) {
            schedule();
            if (signal_pending(current)) {
                  rc = -ERESTARTSYS;
                  break;
            }

            /* get current irq counts */
            spin_lock_irqsave(&info->lock,flags);
            cnow = info->icount;
            newsigs = info->input_signal_events;
            set_current_state(TASK_INTERRUPTIBLE);
            spin_unlock_irqrestore(&info->lock,flags);

            /* if no change, wait aborted for some reason */
            if (newsigs.dsr_up   == oldsigs.dsr_up   &&
                newsigs.dsr_down == oldsigs.dsr_down &&
                newsigs.dcd_up   == oldsigs.dcd_up   &&
                newsigs.dcd_down == oldsigs.dcd_down &&
                newsigs.cts_up   == oldsigs.cts_up   &&
                newsigs.cts_down == oldsigs.cts_down &&
                newsigs.ri_up    == oldsigs.ri_up    &&
                newsigs.ri_down  == oldsigs.ri_down  &&
                cnow.exithunt    == cprev.exithunt   &&
                cnow.rxidle      == cprev.rxidle) {
                  rc = -EIO;
                  break;
            }

            events = mask &
                  ( (newsigs.dsr_up   != oldsigs.dsr_up   ? MgslEvent_DsrActive:0)   +
                    (newsigs.dsr_down != oldsigs.dsr_down ? MgslEvent_DsrInactive:0) +
                    (newsigs.dcd_up   != oldsigs.dcd_up   ? MgslEvent_DcdActive:0)   +
                    (newsigs.dcd_down != oldsigs.dcd_down ? MgslEvent_DcdInactive:0) +
                    (newsigs.cts_up   != oldsigs.cts_up   ? MgslEvent_CtsActive:0)   +
                    (newsigs.cts_down != oldsigs.cts_down ? MgslEvent_CtsInactive:0) +
                    (newsigs.ri_up    != oldsigs.ri_up    ? MgslEvent_RiActive:0)    +
                    (newsigs.ri_down  != oldsigs.ri_down  ? MgslEvent_RiInactive:0)  +
                    (cnow.exithunt    != cprev.exithunt   ? MgslEvent_ExitHuntMode:0) +
                    (cnow.rxidle      != cprev.rxidle     ? MgslEvent_IdleReceived:0) );
            if (events)
                  break;

            cprev = cnow;
            oldsigs = newsigs;
      }

      remove_wait_queue(&info->event_wait_q, &wait);
      set_current_state(TASK_RUNNING);

      if (mask & MgslEvent_ExitHuntMode) {
            spin_lock_irqsave(&info->lock,flags);
            if (!waitqueue_active(&info->event_wait_q))
                  irq_disable(info, CHA, IRQ_EXITHUNT);
            spin_unlock_irqrestore(&info->lock,flags);
      }
exit:
      if (rc == 0)
            PUT_USER(rc, events, mask_ptr);
      return rc;
}

static int modem_input_wait(MGSLPC_INFO *info,int arg)
{
      unsigned long flags;
      int rc;
      struct mgsl_icount cprev, cnow;
      DECLARE_WAITQUEUE(wait, current);

      /* save current irq counts */
      spin_lock_irqsave(&info->lock,flags);
      cprev = info->icount;
      add_wait_queue(&info->status_event_wait_q, &wait);
      set_current_state(TASK_INTERRUPTIBLE);
      spin_unlock_irqrestore(&info->lock,flags);

      for(;;) {
            schedule();
            if (signal_pending(current)) {
                  rc = -ERESTARTSYS;
                  break;
            }

            /* get new irq counts */
            spin_lock_irqsave(&info->lock,flags);
            cnow = info->icount;
            set_current_state(TASK_INTERRUPTIBLE);
            spin_unlock_irqrestore(&info->lock,flags);

            /* if no change, wait aborted for some reason */
            if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
                cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) {
                  rc = -EIO;
                  break;
            }

            /* check for change in caller specified modem input */
            if ((arg & TIOCM_RNG && cnow.rng != cprev.rng) ||
                (arg & TIOCM_DSR && cnow.dsr != cprev.dsr) ||
                (arg & TIOCM_CD  && cnow.dcd != cprev.dcd) ||
                (arg & TIOCM_CTS && cnow.cts != cprev.cts)) {
                  rc = 0;
                  break;
            }

            cprev = cnow;
      }
      remove_wait_queue(&info->status_event_wait_q, &wait);
      set_current_state(TASK_RUNNING);
      return rc;
}

/* return the state of the serial control and status signals
 */
static int tiocmget(struct tty_struct *tty, struct file *file)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned int result;
      unsigned long flags;

      spin_lock_irqsave(&info->lock,flags);
      get_signals(info);
      spin_unlock_irqrestore(&info->lock,flags);

      result = ((info->serial_signals & SerialSignal_RTS) ? TIOCM_RTS:0) +
            ((info->serial_signals & SerialSignal_DTR) ? TIOCM_DTR:0) +
            ((info->serial_signals & SerialSignal_DCD) ? TIOCM_CAR:0) +
            ((info->serial_signals & SerialSignal_RI)  ? TIOCM_RNG:0) +
            ((info->serial_signals & SerialSignal_DSR) ? TIOCM_DSR:0) +
            ((info->serial_signals & SerialSignal_CTS) ? TIOCM_CTS:0);

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):%s tiocmget() value=%08X\n",
                   __FILE__,__LINE__, info->device_name, result );
      return result;
}

/* set modem control signals (DTR/RTS)
 */
static int tiocmset(struct tty_struct *tty, struct file *file,
                unsigned int set, unsigned int clear)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):%s tiocmset(%x,%x)\n",
                  __FILE__,__LINE__,info->device_name, set, clear);

      if (set & TIOCM_RTS)
            info->serial_signals |= SerialSignal_RTS;
      if (set & TIOCM_DTR)
            info->serial_signals |= SerialSignal_DTR;
      if (clear & TIOCM_RTS)
            info->serial_signals &= ~SerialSignal_RTS;
      if (clear & TIOCM_DTR)
            info->serial_signals &= ~SerialSignal_DTR;

      spin_lock_irqsave(&info->lock,flags);
      set_signals(info);
      spin_unlock_irqrestore(&info->lock,flags);

      return 0;
}

/* Set or clear transmit break condition
 *
 * Arguments:           tty         pointer to tty instance data
 *                break_state -1=set break condition, 0=clear
 */
static void mgslpc_break(struct tty_struct *tty, int break_state)
{
      MGSLPC_INFO * info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_break(%s,%d)\n",
                   __FILE__,__LINE__, info->device_name, break_state);

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_break"))
            return;

      spin_lock_irqsave(&info->lock,flags);
      if (break_state == -1)
            set_reg_bits(info, CHA+DAFO, BIT6);
      else
            clear_reg_bits(info, CHA+DAFO, BIT6);
      spin_unlock_irqrestore(&info->lock,flags);
}

/* Service an IOCTL request
 *
 * Arguments:
 *
 *    tty   pointer to tty instance data
 *    file  pointer to associated file object for device
 *    cmd   IOCTL command code
 *    arg   command argument/context
 *
 * Return Value:  0 if success, otherwise error code
 */
static int mgslpc_ioctl(struct tty_struct *tty, struct file * file,
                  unsigned int cmd, unsigned long arg)
{
      MGSLPC_INFO * info = (MGSLPC_INFO *)tty->driver_data;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_ioctl %s cmd=%08X\n", __FILE__,__LINE__,
                  info->device_name, cmd );

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_ioctl"))
            return -ENODEV;

      if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
          (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
            if (tty->flags & (1 << TTY_IO_ERROR))
                return -EIO;
      }

      return ioctl_common(info, cmd, arg);
}

static int ioctl_common(MGSLPC_INFO *info, unsigned int cmd, unsigned long arg)
{
      int error;
      struct mgsl_icount cnow;      /* kernel counter temps */
      struct serial_icounter_struct __user *p_cuser;  /* user space */
      void __user *argp = (void __user *)arg;
      unsigned long flags;

      switch (cmd) {
      case MGSL_IOCGPARAMS:
            return get_params(info, argp);
      case MGSL_IOCSPARAMS:
            return set_params(info, argp);
      case MGSL_IOCGTXIDLE:
            return get_txidle(info, argp);
      case MGSL_IOCSTXIDLE:
            return set_txidle(info, (int)arg);
      case MGSL_IOCGIF:
            return get_interface(info, argp);
      case MGSL_IOCSIF:
            return set_interface(info,(int)arg);
      case MGSL_IOCTXENABLE:
            return set_txenable(info,(int)arg);
      case MGSL_IOCRXENABLE:
            return set_rxenable(info,(int)arg);
      case MGSL_IOCTXABORT:
            return tx_abort(info);
      case MGSL_IOCGSTATS:
            return get_stats(info, argp);
      case MGSL_IOCWAITEVENT:
            return wait_events(info, argp);
      case TIOCMIWAIT:
            return modem_input_wait(info,(int)arg);
      case TIOCGICOUNT:
            spin_lock_irqsave(&info->lock,flags);
            cnow = info->icount;
            spin_unlock_irqrestore(&info->lock,flags);
            p_cuser = argp;
            PUT_USER(error,cnow.cts, &p_cuser->cts);
            if (error) return error;
            PUT_USER(error,cnow.dsr, &p_cuser->dsr);
            if (error) return error;
            PUT_USER(error,cnow.rng, &p_cuser->rng);
            if (error) return error;
            PUT_USER(error,cnow.dcd, &p_cuser->dcd);
            if (error) return error;
            PUT_USER(error,cnow.rx, &p_cuser->rx);
            if (error) return error;
            PUT_USER(error,cnow.tx, &p_cuser->tx);
            if (error) return error;
            PUT_USER(error,cnow.frame, &p_cuser->frame);
            if (error) return error;
            PUT_USER(error,cnow.overrun, &p_cuser->overrun);
            if (error) return error;
            PUT_USER(error,cnow.parity, &p_cuser->parity);
            if (error) return error;
            PUT_USER(error,cnow.brk, &p_cuser->brk);
            if (error) return error;
            PUT_USER(error,cnow.buf_overrun, &p_cuser->buf_overrun);
            if (error) return error;
            return 0;
      default:
            return -ENOIOCTLCMD;
      }
      return 0;
}

/* Set new termios settings
 *
 * Arguments:
 *
 *    tty         pointer to tty structure
 *    termios           pointer to buffer to hold returned old termios
 */
static void mgslpc_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
      MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_set_termios %s\n", __FILE__,__LINE__,
                  tty->driver->name );

      /* just return if nothing has changed */
      if ((tty->termios->c_cflag == old_termios->c_cflag)
          && (RELEVANT_IFLAG(tty->termios->c_iflag)
            == RELEVANT_IFLAG(old_termios->c_iflag)))
        return;

      mgslpc_change_params(info);

      /* Handle transition to B0 status */
      if (old_termios->c_cflag & CBAUD &&
          !(tty->termios->c_cflag & CBAUD)) {
            info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
            spin_lock_irqsave(&info->lock,flags);
            set_signals(info);
            spin_unlock_irqrestore(&info->lock,flags);
      }

      /* Handle transition away from B0 status */
      if (!(old_termios->c_cflag & CBAUD) &&
          tty->termios->c_cflag & CBAUD) {
            info->serial_signals |= SerialSignal_DTR;
            if (!(tty->termios->c_cflag & CRTSCTS) ||
                !test_bit(TTY_THROTTLED, &tty->flags)) {
                  info->serial_signals |= SerialSignal_RTS;
            }
            spin_lock_irqsave(&info->lock,flags);
            set_signals(info);
            spin_unlock_irqrestore(&info->lock,flags);
      }

      /* Handle turning off CRTSCTS */
      if (old_termios->c_cflag & CRTSCTS &&
          !(tty->termios->c_cflag & CRTSCTS)) {
            tty->hw_stopped = 0;
            tx_release(tty);
      }
}

static void mgslpc_close(struct tty_struct *tty, struct file * filp)
{
      MGSLPC_INFO * info = (MGSLPC_INFO *)tty->driver_data;

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_close"))
            return;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_close(%s) entry, count=%d\n",
                   __FILE__,__LINE__, info->device_name, info->count);

      if (!info->count)
            return;

      if (tty_hung_up_p(filp))
            goto cleanup;

      if ((tty->count == 1) && (info->count != 1)) {
            /*
             * tty->count is 1 and the tty structure will be freed.
             * info->count should be one in this case.
             * if it's not, correct it so that the port is shutdown.
             */
            printk("mgslpc_close: bad refcount; tty->count is 1, "
                   "info->count is %d\n", info->count);
            info->count = 1;
      }

      info->count--;

      /* if at least one open remaining, leave hardware active */
      if (info->count)
            goto cleanup;

      info->flags |= ASYNC_CLOSING;

      /* set tty->closing to notify line discipline to
       * only process XON/XOFF characters. Only the N_TTY
       * discipline appears to use this (ppp does not).
       */
      tty->closing = 1;

      /* wait for transmit data to clear all layers */

      if (info->closing_wait != ASYNC_CLOSING_WAIT_NONE) {
            if (debug_level >= DEBUG_LEVEL_INFO)
                  printk("%s(%d):mgslpc_close(%s) calling tty_wait_until_sent\n",
                         __FILE__,__LINE__, info->device_name );
            tty_wait_until_sent(tty, info->closing_wait);
      }

      if (info->flags & ASYNC_INITIALIZED)
            mgslpc_wait_until_sent(tty, info->timeout);

      if (tty->driver->flush_buffer)
            tty->driver->flush_buffer(tty);

      ldisc_flush_buffer(tty);

      shutdown(info);

      tty->closing = 0;
      info->tty = NULL;

      if (info->blocked_open) {
            if (info->close_delay) {
                  msleep_interruptible(jiffies_to_msecs(info->close_delay));
            }
            wake_up_interruptible(&info->open_wait);
      }

      info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING);

      wake_up_interruptible(&info->close_wait);

cleanup:
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_close(%s) exit, count=%d\n", __FILE__,__LINE__,
                  tty->driver->name, info->count);
}

/* Wait until the transmitter is empty.
 */
static void mgslpc_wait_until_sent(struct tty_struct *tty, int timeout)
{
      MGSLPC_INFO * info = (MGSLPC_INFO *)tty->driver_data;
      unsigned long orig_jiffies, char_time;

      if (!info )
            return;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_wait_until_sent(%s) entry\n",
                   __FILE__,__LINE__, info->device_name );

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_wait_until_sent"))
            return;

      if (!(info->flags & ASYNC_INITIALIZED))
            goto exit;

      orig_jiffies = jiffies;

      /* Set check interval to 1/5 of estimated time to
       * send a character, and make it at least 1. The check
       * interval should also be less than the timeout.
       * Note: use tight timings here to satisfy the NIST-PCTS.
       */

      if ( info->params.data_rate ) {
                  char_time = info->timeout/(32 * 5);
            if (!char_time)
                  char_time++;
      } else
            char_time = 1;

      if (timeout)
            char_time = min_t(unsigned long, char_time, timeout);

      if (info->params.mode == MGSL_MODE_HDLC) {
            while (info->tx_active) {
                  msleep_interruptible(jiffies_to_msecs(char_time));
                  if (signal_pending(current))
                        break;
                  if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;
            }
      } else {
            while ((info->tx_count || info->tx_active) &&
                  info->tx_enabled) {
                  msleep_interruptible(jiffies_to_msecs(char_time));
                  if (signal_pending(current))
                        break;
                  if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;
            }
      }

exit:
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_wait_until_sent(%s) exit\n",
                   __FILE__,__LINE__, info->device_name );
}

/* Called by tty_hangup() when a hangup is signaled.
 * This is the same as closing all open files for the port.
 */
static void mgslpc_hangup(struct tty_struct *tty)
{
      MGSLPC_INFO * info = (MGSLPC_INFO *)tty->driver_data;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_hangup(%s)\n",
                   __FILE__,__LINE__, info->device_name );

      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_hangup"))
            return;

      mgslpc_flush_buffer(tty);
      shutdown(info);

      info->count = 0;
      info->flags &= ~ASYNC_NORMAL_ACTIVE;
      info->tty = NULL;

      wake_up_interruptible(&info->open_wait);
}

/* Block the current process until the specified port
 * is ready to be opened.
 */
static int block_til_ready(struct tty_struct *tty, struct file *filp,
                     MGSLPC_INFO *info)
{
      DECLARE_WAITQUEUE(wait, current);
      int         retval;
      int         do_clocal = 0, extra_count = 0;
      unsigned long     flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):block_til_ready on %s\n",
                   __FILE__,__LINE__, tty->driver->name );

      if (filp->f_flags & O_NONBLOCK || tty->flags & (1 << TTY_IO_ERROR)){
            /* nonblock mode is set or port is not enabled */
            /* just verify that callout device is not active */
            info->flags |= ASYNC_NORMAL_ACTIVE;
            return 0;
      }

      if (tty->termios->c_cflag & CLOCAL)
            do_clocal = 1;

      /* Wait for carrier detect and the line to become
       * free (i.e., not in use by the callout).  While we are in
       * this loop, info->count is dropped by one, so that
       * mgslpc_close() knows when to free things.  We restore it upon
       * exit, either normal or abnormal.
       */

      retval = 0;
      add_wait_queue(&info->open_wait, &wait);

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):block_til_ready before block on %s count=%d\n",
                   __FILE__,__LINE__, tty->driver->name, info->count );

      spin_lock_irqsave(&info->lock, flags);
      if (!tty_hung_up_p(filp)) {
            extra_count = 1;
            info->count--;
      }
      spin_unlock_irqrestore(&info->lock, flags);
      info->blocked_open++;

      while (1) {
            if ((tty->termios->c_cflag & CBAUD)) {
                  spin_lock_irqsave(&info->lock,flags);
                  info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
                  set_signals(info);
                  spin_unlock_irqrestore(&info->lock,flags);
            }

            set_current_state(TASK_INTERRUPTIBLE);

            if (tty_hung_up_p(filp) || !(info->flags & ASYNC_INITIALIZED)){
                  retval = (info->flags & ASYNC_HUP_NOTIFY) ?
                              -EAGAIN : -ERESTARTSYS;
                  break;
            }

            spin_lock_irqsave(&info->lock,flags);
            get_signals(info);
            spin_unlock_irqrestore(&info->lock,flags);

            if (!(info->flags & ASYNC_CLOSING) &&
                (do_clocal || (info->serial_signals & SerialSignal_DCD)) ) {
                  break;
            }

            if (signal_pending(current)) {
                  retval = -ERESTARTSYS;
                  break;
            }

            if (debug_level >= DEBUG_LEVEL_INFO)
                  printk("%s(%d):block_til_ready blocking on %s count=%d\n",
                         __FILE__,__LINE__, tty->driver->name, info->count );

            schedule();
      }

      set_current_state(TASK_RUNNING);
      remove_wait_queue(&info->open_wait, &wait);

      if (extra_count)
            info->count++;
      info->blocked_open--;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):block_til_ready after blocking on %s count=%d\n",
                   __FILE__,__LINE__, tty->driver->name, info->count );

      if (!retval)
            info->flags |= ASYNC_NORMAL_ACTIVE;

      return retval;
}

static int mgslpc_open(struct tty_struct *tty, struct file * filp)
{
      MGSLPC_INFO *info;
      int               retval, line;
      unsigned long flags;

      /* verify range of specified line number */
      line = tty->index;
      if ((line < 0) || (line >= mgslpc_device_count)) {
            printk("%s(%d):mgslpc_open with invalid line #%d.\n",
                  __FILE__,__LINE__,line);
            return -ENODEV;
      }

      /* find the info structure for the specified line */
      info = mgslpc_device_list;
      while(info && info->line != line)
            info = info->next_device;
      if (mgslpc_paranoia_check(info, tty->name, "mgslpc_open"))
            return -ENODEV;

      tty->driver_data = info;
      info->tty = tty;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_open(%s), old ref count = %d\n",
                   __FILE__,__LINE__,tty->driver->name, info->count);

      /* If port is closing, signal caller to try again */
      if (tty_hung_up_p(filp) || info->flags & ASYNC_CLOSING){
            if (info->flags & ASYNC_CLOSING)
                  interruptible_sleep_on(&info->close_wait);
            retval = ((info->flags & ASYNC_HUP_NOTIFY) ?
                  -EAGAIN : -ERESTARTSYS);
            goto cleanup;
      }

      info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;

      spin_lock_irqsave(&info->netlock, flags);
      if (info->netcount) {
            retval = -EBUSY;
            spin_unlock_irqrestore(&info->netlock, flags);
            goto cleanup;
      }
      info->count++;
      spin_unlock_irqrestore(&info->netlock, flags);

      if (info->count == 1) {
            /* 1st open on this device, init hardware */
            retval = startup(info);
            if (retval < 0)
                  goto cleanup;
      }

      retval = block_til_ready(tty, filp, info);
      if (retval) {
            if (debug_level >= DEBUG_LEVEL_INFO)
                  printk("%s(%d):block_til_ready(%s) returned %d\n",
                         __FILE__,__LINE__, info->device_name, retval);
            goto cleanup;
      }

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):mgslpc_open(%s) success\n",
                   __FILE__,__LINE__, info->device_name);
      retval = 0;

cleanup:
      if (retval) {
            if (tty->count == 1)
                  info->tty = NULL; /* tty layer will release tty struct */
            if(info->count)
                  info->count--;
      }

      return retval;
}

/*
 * /proc fs routines....
 */

static inline int line_info(char *buf, MGSLPC_INFO *info)
{
      char  stat_buf[30];
      int   ret;
      unsigned long flags;

      ret = sprintf(buf, "%s:io:%04X irq:%d",
                  info->device_name, info->io_base, info->irq_level);

      /* output current serial signal states */
      spin_lock_irqsave(&info->lock,flags);
      get_signals(info);
      spin_unlock_irqrestore(&info->lock,flags);

      stat_buf[0] = 0;
      stat_buf[1] = 0;
      if (info->serial_signals & SerialSignal_RTS)
            strcat(stat_buf, "|RTS");
      if (info->serial_signals & SerialSignal_CTS)
            strcat(stat_buf, "|CTS");
      if (info->serial_signals & SerialSignal_DTR)
            strcat(stat_buf, "|DTR");
      if (info->serial_signals & SerialSignal_DSR)
            strcat(stat_buf, "|DSR");
      if (info->serial_signals & SerialSignal_DCD)
            strcat(stat_buf, "|CD");
      if (info->serial_signals & SerialSignal_RI)
            strcat(stat_buf, "|RI");

      if (info->params.mode == MGSL_MODE_HDLC) {
            ret += sprintf(buf+ret, " HDLC txok:%d rxok:%d",
                        info->icount.txok, info->icount.rxok);
            if (info->icount.txunder)
                  ret += sprintf(buf+ret, " txunder:%d", info->icount.txunder);
            if (info->icount.txabort)
                  ret += sprintf(buf+ret, " txabort:%d", info->icount.txabort);
            if (info->icount.rxshort)
                  ret += sprintf(buf+ret, " rxshort:%d", info->icount.rxshort);
            if (info->icount.rxlong)
                  ret += sprintf(buf+ret, " rxlong:%d", info->icount.rxlong);
            if (info->icount.rxover)
                  ret += sprintf(buf+ret, " rxover:%d", info->icount.rxover);
            if (info->icount.rxcrc)
                  ret += sprintf(buf+ret, " rxcrc:%d", info->icount.rxcrc);
      } else {
            ret += sprintf(buf+ret, " ASYNC tx:%d rx:%d",
                        info->icount.tx, info->icount.rx);
            if (info->icount.frame)
                  ret += sprintf(buf+ret, " fe:%d", info->icount.frame);
            if (info->icount.parity)
                  ret += sprintf(buf+ret, " pe:%d", info->icount.parity);
            if (info->icount.brk)
                  ret += sprintf(buf+ret, " brk:%d", info->icount.brk);
            if (info->icount.overrun)
                  ret += sprintf(buf+ret, " oe:%d", info->icount.overrun);
      }

      /* Append serial signal status to end */
      ret += sprintf(buf+ret, " %s\n", stat_buf+1);

      ret += sprintf(buf+ret, "txactive=%d bh_req=%d bh_run=%d pending_bh=%x\n",
                   info->tx_active,info->bh_requested,info->bh_running,
                   info->pending_bh);

      return ret;
}

/* Called to print information about devices
 */
static int mgslpc_read_proc(char *page, char **start, off_t off, int count,
             int *eof, void *data)
{
      int len = 0, l;
      off_t begin = 0;
      MGSLPC_INFO *info;

      len += sprintf(page, "synclink driver:%s\n", driver_version);

      info = mgslpc_device_list;
      while( info ) {
            l = line_info(page + len, info);
            len += l;
            if (len+begin > off+count)
                  goto done;
            if (len+begin < off) {
                  begin += len;
                  len = 0;
            }
            info = info->next_device;
      }

      *eof = 1;
done:
      if (off >= len+begin)
            return 0;
      *start = page + (off-begin);
      return ((count < begin+len-off) ? count : begin+len-off);
}

static int rx_alloc_buffers(MGSLPC_INFO *info)
{
      /* each buffer has header and data */
      info->rx_buf_size = sizeof(RXBUF) + info->max_frame_size;

      /* calculate total allocation size for 8 buffers */
      info->rx_buf_total_size = info->rx_buf_size * 8;

      /* limit total allocated memory */
      if (info->rx_buf_total_size > 0x10000)
            info->rx_buf_total_size = 0x10000;

      /* calculate number of buffers */
      info->rx_buf_count = info->rx_buf_total_size / info->rx_buf_size;

      info->rx_buf = kmalloc(info->rx_buf_total_size, GFP_KERNEL);
      if (info->rx_buf == NULL)
            return -ENOMEM;

      rx_reset_buffers(info);
      return 0;
}

static void rx_free_buffers(MGSLPC_INFO *info)
{
      kfree(info->rx_buf);
      info->rx_buf = NULL;
}

static int claim_resources(MGSLPC_INFO *info)
{
      if (rx_alloc_buffers(info) < 0 ) {
            printk( "Cant allocate rx buffer %s\n", info->device_name);
            release_resources(info);
            return -ENODEV;
      }
      return 0;
}

static void release_resources(MGSLPC_INFO *info)
{
      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("release_resources(%s)\n", info->device_name);
      rx_free_buffers(info);
}

/* Add the specified device instance data structure to the
 * global linked list of devices and increment the device count.
 *
 * Arguments:           info  pointer to device instance data
 */
static void mgslpc_add_device(MGSLPC_INFO *info)
{
      info->next_device = NULL;
      info->line = mgslpc_device_count;
      sprintf(info->device_name,"ttySLP%d",info->line);

      if (info->line < MAX_DEVICE_COUNT) {
            if (maxframe[info->line])
                  info->max_frame_size = maxframe[info->line];
            info->dosyncppp = dosyncppp[info->line];
      }

      mgslpc_device_count++;

      if (!mgslpc_device_list)
            mgslpc_device_list = info;
      else {
            MGSLPC_INFO *current_dev = mgslpc_device_list;
            while( current_dev->next_device )
                  current_dev = current_dev->next_device;
            current_dev->next_device = info;
      }

      if (info->max_frame_size < 4096)
            info->max_frame_size = 4096;
      else if (info->max_frame_size > 65535)
            info->max_frame_size = 65535;

      printk( "SyncLink PC Card %s:IO=%04X IRQ=%d\n",
            info->device_name, info->io_base, info->irq_level);

#if SYNCLINK_GENERIC_HDLC
      hdlcdev_init(info);
#endif
}

static void mgslpc_remove_device(MGSLPC_INFO *remove_info)
{
      MGSLPC_INFO *info = mgslpc_device_list;
      MGSLPC_INFO *last = NULL;

      while(info) {
            if (info == remove_info) {
                  if (last)
                        last->next_device = info->next_device;
                  else
                        mgslpc_device_list = info->next_device;
#if SYNCLINK_GENERIC_HDLC
                  hdlcdev_exit(info);
#endif
                  release_resources(info);
                  kfree(info);
                  mgslpc_device_count--;
                  return;
            }
            last = info;
            info = info->next_device;
      }
}

static struct pcmcia_device_id mgslpc_ids[] = {
      PCMCIA_DEVICE_MANF_CARD(0x02c5, 0x0050),
      PCMCIA_DEVICE_NULL
};
MODULE_DEVICE_TABLE(pcmcia, mgslpc_ids);

static struct pcmcia_driver mgslpc_driver = {
      .owner            = THIS_MODULE,
      .drv        = {
            .name = "synclink_cs",
      },
      .probe            = mgslpc_probe,
      .remove           = mgslpc_detach,
      .id_table   = mgslpc_ids,
      .suspend    = mgslpc_suspend,
      .resume           = mgslpc_resume,
};

static const struct tty_operations mgslpc_ops = {
      .open = mgslpc_open,
      .close = mgslpc_close,
      .write = mgslpc_write,
      .put_char = mgslpc_put_char,
      .flush_chars = mgslpc_flush_chars,
      .write_room = mgslpc_write_room,
      .chars_in_buffer = mgslpc_chars_in_buffer,
      .flush_buffer = mgslpc_flush_buffer,
      .ioctl = mgslpc_ioctl,
      .throttle = mgslpc_throttle,
      .unthrottle = mgslpc_unthrottle,
      .send_xchar = mgslpc_send_xchar,
      .break_ctl = mgslpc_break,
      .wait_until_sent = mgslpc_wait_until_sent,
      .read_proc = mgslpc_read_proc,
      .set_termios = mgslpc_set_termios,
      .stop = tx_pause,
      .start = tx_release,
      .hangup = mgslpc_hangup,
      .tiocmget = tiocmget,
      .tiocmset = tiocmset,
};

static void synclink_cs_cleanup(void)
{
      int rc;

      printk("Unloading %s: version %s\n", driver_name, driver_version);

      while(mgslpc_device_list)
            mgslpc_remove_device(mgslpc_device_list);

      if (serial_driver) {
            if ((rc = tty_unregister_driver(serial_driver)))
                  printk("%s(%d) failed to unregister tty driver err=%d\n",
                         __FILE__,__LINE__,rc);
            put_tty_driver(serial_driver);
      }

      pcmcia_unregister_driver(&mgslpc_driver);
}

static int __init synclink_cs_init(void)
{
    int rc;

    if (break_on_load) {
          mgslpc_get_text_ptr();
          BREAKPOINT();
    }

    printk("%s %s\n", driver_name, driver_version);

    if ((rc = pcmcia_register_driver(&mgslpc_driver)) < 0)
          return rc;

    serial_driver = alloc_tty_driver(MAX_DEVICE_COUNT);
    if (!serial_driver) {
          rc = -ENOMEM;
          goto error;
    }

    /* Initialize the tty_driver structure */

    serial_driver->owner = THIS_MODULE;
    serial_driver->driver_name = "synclink_cs";
    serial_driver->name = "ttySLP";
    serial_driver->major = ttymajor;
    serial_driver->minor_start = 64;
    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;
    tty_set_operations(serial_driver, &mgslpc_ops);

    if ((rc = tty_register_driver(serial_driver)) < 0) {
          printk("%s(%d):Couldn't register serial driver\n",
               __FILE__,__LINE__);
          put_tty_driver(serial_driver);
          serial_driver = NULL;
          goto error;
    }

    printk("%s %s, tty major#%d\n",
         driver_name, driver_version,
         serial_driver->major);

    return 0;

error:
    synclink_cs_cleanup();
    return rc;
}

static void __exit synclink_cs_exit(void)
{
      synclink_cs_cleanup();
}

module_init(synclink_cs_init);
module_exit(synclink_cs_exit);

static void mgslpc_set_rate(MGSLPC_INFO *info, unsigned char channel, unsigned int rate)
{
      unsigned int M, N;
      unsigned char val;

      /* note:standard BRG mode is broken in V3.2 chip
       * so enhanced mode is always used
       */

      if (rate) {
            N = 3686400 / rate;
            if (!N)
                  N = 1;
            N >>= 1;
            for (M = 1; N > 64 && M < 16; M++)
                  N >>= 1;
            N--;

            /* BGR[5..0] = N
             * BGR[9..6] = M
             * BGR[7..0] contained in BGR register
             * BGR[9..8] contained in CCR2[7..6]
             * divisor = (N+1)*2^M
             *
             * Note: M *must* not be zero (causes asymetric duty cycle)
             */
            write_reg(info, (unsigned char) (channel + BGR),
                          (unsigned char) ((M << 6) + N));
            val = read_reg(info, (unsigned char) (channel + CCR2)) & 0x3f;
            val |= ((M << 4) & 0xc0);
            write_reg(info, (unsigned char) (channel + CCR2), val);
      }
}

/* Enabled the AUX clock output at the specified frequency.
 */
static void enable_auxclk(MGSLPC_INFO *info)
{
      unsigned char val;

      /* MODE
       *
       * 07..06  MDS[1..0] 10 = transparent HDLC mode
       * 05      ADM Address Mode, 0 = no addr recognition
       * 04      TMD Timer Mode, 0 = external
       * 03      RAC Receiver Active, 0 = inactive
       * 02      RTS 0=RTS active during xmit, 1=RTS always active
       * 01      TRS Timer Resolution, 1=512
       * 00      TLP Test Loop, 0 = no loop
       *
       * 1000 0010
       */
      val = 0x82;

      /* channel B RTS is used to enable AUXCLK driver on SP505 */
      if (info->params.mode == MGSL_MODE_HDLC && info->params.clock_speed)
            val |= BIT2;
      write_reg(info, CHB + MODE, val);

      /* CCR0
       *
       * 07      PU Power Up, 1=active, 0=power down
       * 06      MCE Master Clock Enable, 1=enabled
       * 05      Reserved, 0
       * 04..02  SC[2..0] Encoding
       * 01..00  SM[1..0] Serial Mode, 00=HDLC
       *
       * 11000000
       */
      write_reg(info, CHB + CCR0, 0xc0);

      /* CCR1
       *
       * 07      SFLG Shared Flag, 0 = disable shared flags
       * 06      GALP Go Active On Loop, 0 = not used
       * 05      GLP Go On Loop, 0 = not used
       * 04      ODS Output Driver Select, 1=TxD is push-pull output
       * 03      ITF Interframe Time Fill, 0=mark, 1=flag
       * 02..00  CM[2..0] Clock Mode
       *
       * 0001 0111
       */
      write_reg(info, CHB + CCR1, 0x17);

      /* CCR2 (Channel B)
       *
       * 07..06  BGR[9..8] Baud rate bits 9..8
       * 05      BDF Baud rate divisor factor, 0=1, 1=BGR value
       * 04      SSEL Clock source select, 1=submode b
       * 03      TOE 0=TxCLK is input, 1=TxCLK is output
       * 02      RWX Read/Write Exchange 0=disabled
       * 01      C32, CRC select, 0=CRC-16, 1=CRC-32
       * 00      DIV, data inversion 0=disabled, 1=enabled
       *
       * 0011 1000
       */
      if (info->params.mode == MGSL_MODE_HDLC && info->params.clock_speed)
            write_reg(info, CHB + CCR2, 0x38);
      else
            write_reg(info, CHB + CCR2, 0x30);

      /* CCR4
       *
       * 07      MCK4 Master Clock Divide by 4, 1=enabled
       * 06      EBRG Enhanced Baud Rate Generator Mode, 1=enabled
       * 05      TST1 Test Pin, 0=normal operation
       * 04      ICD Ivert Carrier Detect, 1=enabled (active low)
       * 03..02  Reserved, must be 0
       * 01..00  RFT[1..0] RxFIFO Threshold 00=32 bytes
       *
       * 0101 0000
       */
      write_reg(info, CHB + CCR4, 0x50);

      /* if auxclk not enabled, set internal BRG so
       * CTS transitions can be detected (requires TxC)
       */
      if (info->params.mode == MGSL_MODE_HDLC && info->params.clock_speed)
            mgslpc_set_rate(info, CHB, info->params.clock_speed);
      else
            mgslpc_set_rate(info, CHB, 921600);
}

static void loopback_enable(MGSLPC_INFO *info)
{
      unsigned char val;

      /* CCR1:02..00  CM[2..0] Clock Mode = 111 (clock mode 7) */
      val = read_reg(info, CHA + CCR1) | (BIT2 + BIT1 + BIT0);
      write_reg(info, CHA + CCR1, val);

      /* CCR2:04 SSEL Clock source select, 1=submode b */
      val = read_reg(info, CHA + CCR2) | (BIT4 + BIT5);
      write_reg(info, CHA + CCR2, val);

      /* set LinkSpeed if available, otherwise default to 2Mbps */
      if (info->params.clock_speed)
            mgslpc_set_rate(info, CHA, info->params.clock_speed);
      else
            mgslpc_set_rate(info, CHA, 1843200);

      /* MODE:00 TLP Test Loop, 1=loopback enabled */
      val = read_reg(info, CHA + MODE) | BIT0;
      write_reg(info, CHA + MODE, val);
}

static void hdlc_mode(MGSLPC_INFO *info)
{
      unsigned char val;
      unsigned char clkmode, clksubmode;

      /* disable all interrupts */
      irq_disable(info, CHA, 0xffff);
      irq_disable(info, CHB, 0xffff);
      port_irq_disable(info, 0xff);

      /* assume clock mode 0a, rcv=RxC xmt=TxC */
      clkmode = clksubmode = 0;
      if (info->params.flags & HDLC_FLAG_RXC_DPLL
          && info->params.flags & HDLC_FLAG_TXC_DPLL) {
            /* clock mode 7a, rcv = DPLL, xmt = DPLL */
            clkmode = 7;
      } else if (info->params.flags & HDLC_FLAG_RXC_BRG
             && info->params.flags & HDLC_FLAG_TXC_BRG) {
            /* clock mode 7b, rcv = BRG, xmt = BRG */
            clkmode = 7;
            clksubmode = 1;
      } else if (info->params.flags & HDLC_FLAG_RXC_DPLL) {
            if (info->params.flags & HDLC_FLAG_TXC_BRG) {
                  /* clock mode 6b, rcv = DPLL, xmt = BRG/16 */
                  clkmode = 6;
                  clksubmode = 1;
            } else {
                  /* clock mode 6a, rcv = DPLL, xmt = TxC */
                  clkmode = 6;
            }
      } else if (info->params.flags & HDLC_FLAG_TXC_BRG) {
            /* clock mode 0b, rcv = RxC, xmt = BRG */
            clksubmode = 1;
      }

      /* MODE
       *
       * 07..06  MDS[1..0] 10 = transparent HDLC mode
       * 05      ADM Address Mode, 0 = no addr recognition
       * 04      TMD Timer Mode, 0 = external
       * 03      RAC Receiver Active, 0 = inactive
       * 02      RTS 0=RTS active during xmit, 1=RTS always active
       * 01      TRS Timer Resolution, 1=512
       * 00      TLP Test Loop, 0 = no loop
       *
       * 1000 0010
       */
      val = 0x82;
      if (info->params.loopback)
            val |= BIT0;

      /* preserve RTS state */
      if (info->serial_signals & SerialSignal_RTS)
            val |= BIT2;
      write_reg(info, CHA + MODE, val);

      /* CCR0
       *
       * 07      PU Power Up, 1=active, 0=power down
       * 06      MCE Master Clock Enable, 1=enabled
       * 05      Reserved, 0
       * 04..02  SC[2..0] Encoding
       * 01..00  SM[1..0] Serial Mode, 00=HDLC
       *
       * 11000000
       */
      val = 0xc0;
      switch (info->params.encoding)
      {
      case HDLC_ENCODING_NRZI:
            val |= BIT3;
            break;
      case HDLC_ENCODING_BIPHASE_SPACE:
            val |= BIT4;
            break;            // FM0
      case HDLC_ENCODING_BIPHASE_MARK:
            val |= BIT4 + BIT2;
            break;            // FM1
      case HDLC_ENCODING_BIPHASE_LEVEL:
            val |= BIT4 + BIT3;
            break;            // Manchester
      }
      write_reg(info, CHA + CCR0, val);

      /* CCR1
       *
       * 07      SFLG Shared Flag, 0 = disable shared flags
       * 06      GALP Go Active On Loop, 0 = not used
       * 05      GLP Go On Loop, 0 = not used
       * 04      ODS Output Driver Select, 1=TxD is push-pull output
       * 03      ITF Interframe Time Fill, 0=mark, 1=flag
       * 02..00  CM[2..0] Clock Mode
       *
       * 0001 0000
       */
      val = 0x10 + clkmode;
      write_reg(info, CHA + CCR1, val);

      /* CCR2
       *
       * 07..06  BGR[9..8] Baud rate bits 9..8
       * 05      BDF Baud rate divisor factor, 0=1, 1=BGR value
       * 04      SSEL Clock source select, 1=submode b
       * 03      TOE 0=TxCLK is input, 0=TxCLK is input
       * 02      RWX Read/Write Exchange 0=disabled
       * 01      C32, CRC select, 0=CRC-16, 1=CRC-32
       * 00      DIV, data inversion 0=disabled, 1=enabled
       *
       * 0000 0000
       */
      val = 0x00;
      if (clkmode == 2 || clkmode == 3 || clkmode == 6
          || clkmode == 7 || (clkmode == 0 && clksubmode == 1))
            val |= BIT5;
      if (clksubmode)
            val |= BIT4;
      if (info->params.crc_type == HDLC_CRC_32_CCITT)
            val |= BIT1;
      if (info->params.encoding == HDLC_ENCODING_NRZB)
            val |= BIT0;
      write_reg(info, CHA + CCR2, val);

      /* CCR3
       *
       * 07..06  PRE[1..0] Preamble count 00=1, 01=2, 10=4, 11=8
       * 05      EPT Enable preamble transmission, 1=enabled
       * 04      RADD Receive address pushed to FIFO, 0=disabled
       * 03      CRL CRC Reset Level, 0=FFFF
       * 02      RCRC Rx CRC 0=On 1=Off
       * 01      TCRC Tx CRC 0=On 1=Off
       * 00      PSD DPLL Phase Shift Disable
       *
       * 0000 0000
       */
      val = 0x00;
      if (info->params.crc_type == HDLC_CRC_NONE)
            val |= BIT2 + BIT1;
      if (info->params.preamble != HDLC_PREAMBLE_PATTERN_NONE)
            val |= BIT5;
      switch (info->params.preamble_length)
      {
      case HDLC_PREAMBLE_LENGTH_16BITS:
            val |= BIT6;
            break;
      case HDLC_PREAMBLE_LENGTH_32BITS:
            val |= BIT6;
            break;
      case HDLC_PREAMBLE_LENGTH_64BITS:
            val |= BIT7 + BIT6;
            break;
      }
      write_reg(info, CHA + CCR3, val);

      /* PRE - Preamble pattern */
      val = 0;
      switch (info->params.preamble)
      {
      case HDLC_PREAMBLE_PATTERN_FLAGS: val = 0x7e; break;
      case HDLC_PREAMBLE_PATTERN_10:    val = 0xaa; break;
      case HDLC_PREAMBLE_PATTERN_01:    val = 0x55; break;
      case HDLC_PREAMBLE_PATTERN_ONES:  val = 0xff; break;
      }
      write_reg(info, CHA + PRE, val);

      /* CCR4
       *
       * 07      MCK4 Master Clock Divide by 4, 1=enabled
       * 06      EBRG Enhanced Baud Rate Generator Mode, 1=enabled
       * 05      TST1 Test Pin, 0=normal operation
       * 04      ICD Ivert Carrier Detect, 1=enabled (active low)
       * 03..02  Reserved, must be 0
       * 01..00  RFT[1..0] RxFIFO Threshold 00=32 bytes
       *
       * 0101 0000
       */
      val = 0x50;
      write_reg(info, CHA + CCR4, val);
      if (info->params.flags & HDLC_FLAG_RXC_DPLL)
            mgslpc_set_rate(info, CHA, info->params.clock_speed * 16);
      else
            mgslpc_set_rate(info, CHA, info->params.clock_speed);

      /* RLCR Receive length check register
       *
       * 7     1=enable receive length check
       * 6..0  Max frame length = (RL + 1) * 32
       */
      write_reg(info, CHA + RLCR, 0);

      /* XBCH Transmit Byte Count High
       *
       * 07      DMA mode, 0 = interrupt driven
       * 06      NRM, 0=ABM (ignored)
       * 05      CAS Carrier Auto Start
       * 04      XC Transmit Continuously (ignored)
       * 03..00  XBC[10..8] Transmit byte count bits 10..8
       *
       * 0000 0000
       */
      val = 0x00;
      if (info->params.flags & HDLC_FLAG_AUTO_DCD)
            val |= BIT5;
      write_reg(info, CHA + XBCH, val);
      enable_auxclk(info);
      if (info->params.loopback || info->testing_irq)
            loopback_enable(info);
      if (info->params.flags & HDLC_FLAG_AUTO_CTS)
      {
            irq_enable(info, CHB, IRQ_CTS);
            /* PVR[3] 1=AUTO CTS active */
            set_reg_bits(info, CHA + PVR, BIT3);
      } else
            clear_reg_bits(info, CHA + PVR, BIT3);

      irq_enable(info, CHA,
                   IRQ_RXEOM + IRQ_RXFIFO + IRQ_ALLSENT +
                   IRQ_UNDERRUN + IRQ_TXFIFO);
      issue_command(info, CHA, CMD_TXRESET + CMD_RXRESET);
      wait_command_complete(info, CHA);
      read_reg16(info, CHA + ISR);  /* clear pending IRQs */

      /* Master clock mode enabled above to allow reset commands
       * to complete even if no data clocks are present.
       *
       * Disable master clock mode for normal communications because
       * V3.2 of the ESCC2 has a bug that prevents the transmit all sent
       * IRQ when in master clock mode.
       *
       * Leave master clock mode enabled for IRQ test because the
       * timer IRQ used by the test can only happen in master clock mode.
       */
      if (!info->testing_irq)
            clear_reg_bits(info, CHA + CCR0, BIT6);

      tx_set_idle(info);

      tx_stop(info);
      rx_stop(info);
}

static void rx_stop(MGSLPC_INFO *info)
{
      if (debug_level >= DEBUG_LEVEL_ISR)
            printk("%s(%d):rx_stop(%s)\n",
                   __FILE__,__LINE__, info->device_name );

      /* MODE:03 RAC Receiver Active, 0=inactive */
      clear_reg_bits(info, CHA + MODE, BIT3);

      info->rx_enabled = 0;
      info->rx_overflow = 0;
}

static void rx_start(MGSLPC_INFO *info)
{
      if (debug_level >= DEBUG_LEVEL_ISR)
            printk("%s(%d):rx_start(%s)\n",
                   __FILE__,__LINE__, info->device_name );

      rx_reset_buffers(info);
      info->rx_enabled = 0;
      info->rx_overflow = 0;

      /* MODE:03 RAC Receiver Active, 1=active */
      set_reg_bits(info, CHA + MODE, BIT3);

      info->rx_enabled = 1;
}

static void tx_start(MGSLPC_INFO *info)
{
      if (debug_level >= DEBUG_LEVEL_ISR)
            printk("%s(%d):tx_start(%s)\n",
                   __FILE__,__LINE__, info->device_name );

      if (info->tx_count) {
            /* If auto RTS enabled and RTS is inactive, then assert */
            /* RTS and set a flag indicating that the driver should */
            /* negate RTS when the transmission completes. */
            info->drop_rts_on_tx_done = 0;

            if (info->params.flags & HDLC_FLAG_AUTO_RTS) {
                  get_signals(info);
                  if (!(info->serial_signals & SerialSignal_RTS)) {
                        info->serial_signals |= SerialSignal_RTS;
                        set_signals(info);
                        info->drop_rts_on_tx_done = 1;
                  }
            }

            if (info->params.mode == MGSL_MODE_ASYNC) {
                  if (!info->tx_active) {
                        info->tx_active = 1;
                        tx_ready(info);
                  }
            } else {
                  info->tx_active = 1;
                  tx_ready(info);
                  mod_timer(&info->tx_timer, jiffies +
                              msecs_to_jiffies(5000));
            }
      }

      if (!info->tx_enabled)
            info->tx_enabled = 1;
}

static void tx_stop(MGSLPC_INFO *info)
{
      if (debug_level >= DEBUG_LEVEL_ISR)
            printk("%s(%d):tx_stop(%s)\n",
                   __FILE__,__LINE__, info->device_name );

      del_timer(&info->tx_timer);

      info->tx_enabled = 0;
      info->tx_active  = 0;
}

/* Reset the adapter to a known state and prepare it for further use.
 */
static void reset_device(MGSLPC_INFO *info)
{
      /* power up both channels (set BIT7) */
      write_reg(info, CHA + CCR0, 0x80);
      write_reg(info, CHB + CCR0, 0x80);
      write_reg(info, CHA + MODE, 0);
      write_reg(info, CHB + MODE, 0);

      /* disable all interrupts */
      irq_disable(info, CHA, 0xffff);
      irq_disable(info, CHB, 0xffff);
      port_irq_disable(info, 0xff);

      /* PCR Port Configuration Register
       *
       * 07..04  DEC[3..0] Serial I/F select outputs
       * 03      output, 1=AUTO CTS control enabled
       * 02      RI Ring Indicator input 0=active
       * 01      DSR input 0=active
       * 00      DTR output 0=active
       *
       * 0000 0110
       */
      write_reg(info, PCR, 0x06);

      /* PVR Port Value Register
       *
       * 07..04  DEC[3..0] Serial I/F select (0000=disabled)
       * 03      AUTO CTS output 1=enabled
       * 02      RI Ring Indicator input
       * 01      DSR input
       * 00      DTR output (1=inactive)
       *
       * 0000 0001
       */
//    write_reg(info, PVR, PVR_DTR);

      /* IPC Interrupt Port Configuration
       *
       * 07      VIS 1=Masked interrupts visible
       * 06..05  Reserved, 0
       * 04..03  SLA Slave address, 00 ignored
       * 02      CASM Cascading Mode, 1=daisy chain
       * 01..00  IC[1..0] Interrupt Config, 01=push-pull output, active low
       *
       * 0000 0101
       */
      write_reg(info, IPC, 0x05);
}

static void async_mode(MGSLPC_INFO *info)
{
      unsigned char val;

      /* disable all interrupts */
      irq_disable(info, CHA, 0xffff);
      irq_disable(info, CHB, 0xffff);
      port_irq_disable(info, 0xff);

      /* MODE
       *
       * 07      Reserved, 0
       * 06      FRTS RTS State, 0=active
       * 05      FCTS Flow Control on CTS
       * 04      FLON Flow Control Enable
       * 03      RAC Receiver Active, 0 = inactive
       * 02      RTS 0=Auto RTS, 1=manual RTS
       * 01      TRS Timer Resolution, 1=512
       * 00      TLP Test Loop, 0 = no loop
       *
       * 0000 0110
       */
      val = 0x06;
      if (info->params.loopback)
            val |= BIT0;

      /* preserve RTS state */
      if (!(info->serial_signals & SerialSignal_RTS))
            val |= BIT6;
      write_reg(info, CHA + MODE, val);

      /* CCR0
       *
       * 07      PU Power Up, 1=active, 0=power down
       * 06      MCE Master Clock Enable, 1=enabled
       * 05      Reserved, 0
       * 04..02  SC[2..0] Encoding, 000=NRZ
       * 01..00  SM[1..0] Serial Mode, 11=Async
       *
       * 1000 0011
       */
      write_reg(info, CHA + CCR0, 0x83);

      /* CCR1
       *
       * 07..05  Reserved, 0
       * 04      ODS Output Driver Select, 1=TxD is push-pull output
       * 03      BCR Bit Clock Rate, 1=16x
       * 02..00  CM[2..0] Clock Mode, 111=BRG
       *
       * 0001 1111
       */
      write_reg(info, CHA + CCR1, 0x1f);

      /* CCR2 (channel A)
       *
       * 07..06  BGR[9..8] Baud rate bits 9..8
       * 05      BDF Baud rate divisor factor, 0=1, 1=BGR value
       * 04      SSEL Clock source select, 1=submode b
       * 03      TOE 0=TxCLK is input, 0=TxCLK is input
       * 02      RWX Read/Write Exchange 0=disabled
       * 01      Reserved, 0
       * 00      DIV, data inversion 0=disabled, 1=enabled
       *
       * 0001 0000
       */
      write_reg(info, CHA + CCR2, 0x10);

      /* CCR3
       *
       * 07..01  Reserved, 0
       * 00      PSD DPLL Phase Shift Disable
       *
       * 0000 0000
       */
      write_reg(info, CHA + CCR3, 0);

      /* CCR4
       *
       * 07      MCK4 Master Clock Divide by 4, 1=enabled
       * 06      EBRG Enhanced Baud Rate Generator Mode, 1=enabled
       * 05      TST1 Test Pin, 0=normal operation
       * 04      ICD Ivert Carrier Detect, 1=enabled (active low)
       * 03..00  Reserved, must be 0
       *
       * 0101 0000
       */
      write_reg(info, CHA + CCR4, 0x50);
      mgslpc_set_rate(info, CHA, info->params.data_rate * 16);

      /* DAFO Data Format
       *
       * 07      Reserved, 0
       * 06      XBRK transmit break, 0=normal operation
       * 05      Stop bits (0=1, 1=2)
       * 04..03  PAR[1..0] Parity (01=odd, 10=even)
       * 02      PAREN Parity Enable
       * 01..00  CHL[1..0] Character Length (00=8, 01=7)
       *
       */
      val = 0x00;
      if (info->params.data_bits != 8)
            val |= BIT0;      /* 7 bits */
      if (info->params.stop_bits != 1)
            val |= BIT5;
      if (info->params.parity != ASYNC_PARITY_NONE)
      {
            val |= BIT2;      /* Parity enable */
            if (info->params.parity == ASYNC_PARITY_ODD)
                  val |= BIT3;
            else
                  val |= BIT4;
      }
      write_reg(info, CHA + DAFO, val);

      /* RFC Rx FIFO Control
       *
       * 07      Reserved, 0
       * 06      DPS, 1=parity bit not stored in data byte
       * 05      DXS, 0=all data stored in FIFO (including XON/XOFF)
       * 04      RFDF Rx FIFO Data Format, 1=status byte stored in FIFO
       * 03..02  RFTH[1..0], rx threshold, 11=16 status + 16 data byte
       * 01      Reserved, 0
       * 00      TCDE Terminate Char Detect Enable, 0=disabled
       *
       * 0101 1100
       */
      write_reg(info, CHA + RFC, 0x5c);

      /* RLCR Receive length check register
       *
       * Max frame length = (RL + 1) * 32
       */
      write_reg(info, CHA + RLCR, 0);

      /* XBCH Transmit Byte Count High
       *
       * 07      DMA mode, 0 = interrupt driven
       * 06      NRM, 0=ABM (ignored)
       * 05      CAS Carrier Auto Start
       * 04      XC Transmit Continuously (ignored)
       * 03..00  XBC[10..8] Transmit byte count bits 10..8
       *
       * 0000 0000
       */
      val = 0x00;
      if (info->params.flags & HDLC_FLAG_AUTO_DCD)
            val |= BIT5;
      write_reg(info, CHA + XBCH, val);
      if (info->params.flags & HDLC_FLAG_AUTO_CTS)
            irq_enable(info, CHA, IRQ_CTS);

      /* MODE:03 RAC Receiver Active, 1=active */
      set_reg_bits(info, CHA + MODE, BIT3);
      enable_auxclk(info);
      if (info->params.flags & HDLC_FLAG_AUTO_CTS) {
            irq_enable(info, CHB, IRQ_CTS);
            /* PVR[3] 1=AUTO CTS active */
            set_reg_bits(info, CHA + PVR, BIT3);
      } else
            clear_reg_bits(info, CHA + PVR, BIT3);
      irq_enable(info, CHA,
                    IRQ_RXEOM + IRQ_RXFIFO + IRQ_BREAK_ON + IRQ_RXTIME +
                    IRQ_ALLSENT + IRQ_TXFIFO);
      issue_command(info, CHA, CMD_TXRESET + CMD_RXRESET);
      wait_command_complete(info, CHA);
      read_reg16(info, CHA + ISR);  /* clear pending IRQs */
}

/* Set the HDLC idle mode for the transmitter.
 */
static void tx_set_idle(MGSLPC_INFO *info)
{
      /* Note: ESCC2 only supports flags and one idle modes */
      if (info->idle_mode == HDLC_TXIDLE_FLAGS)
            set_reg_bits(info, CHA + CCR1, BIT3);
      else
            clear_reg_bits(info, CHA + CCR1, BIT3);
}

/* get state of the V24 status (input) signals.
 */
static void get_signals(MGSLPC_INFO *info)
{
      unsigned char status = 0;

      /* preserve DTR and RTS */
      info->serial_signals &= SerialSignal_DTR + SerialSignal_RTS;

      if (read_reg(info, CHB + VSTR) & BIT7)
            info->serial_signals |= SerialSignal_DCD;
      if (read_reg(info, CHB + STAR) & BIT1)
            info->serial_signals |= SerialSignal_CTS;

      status = read_reg(info, CHA + PVR);
      if (!(status & PVR_RI))
            info->serial_signals |= SerialSignal_RI;
      if (!(status & PVR_DSR))
            info->serial_signals |= SerialSignal_DSR;
}

/* Set the state of DTR and RTS based on contents of
 * serial_signals member of device extension.
 */
static void set_signals(MGSLPC_INFO *info)
{
      unsigned char val;

      val = read_reg(info, CHA + MODE);
      if (info->params.mode == MGSL_MODE_ASYNC) {
            if (info->serial_signals & SerialSignal_RTS)
                  val &= ~BIT6;
            else
                  val |= BIT6;
      } else {
            if (info->serial_signals & SerialSignal_RTS)
                  val |= BIT2;
            else
                  val &= ~BIT2;
      }
      write_reg(info, CHA + MODE, val);

      if (info->serial_signals & SerialSignal_DTR)
            clear_reg_bits(info, CHA + PVR, PVR_DTR);
      else
            set_reg_bits(info, CHA + PVR, PVR_DTR);
}

static void rx_reset_buffers(MGSLPC_INFO *info)
{
      RXBUF *buf;
      int i;

      info->rx_put = 0;
      info->rx_get = 0;
      info->rx_frame_count = 0;
      for (i=0 ; i < info->rx_buf_count ; i++) {
            buf = (RXBUF*)(info->rx_buf + (i * info->rx_buf_size));
            buf->status = buf->count = 0;
      }
}

/* Attempt to return a received HDLC frame
 * Only frames received without errors are returned.
 *
 * Returns 1 if frame returned, otherwise 0
 */
static int rx_get_frame(MGSLPC_INFO *info)
{
      unsigned short status;
      RXBUF *buf;
      unsigned int framesize = 0;
      unsigned long flags;
      struct tty_struct *tty = info->tty;
      int return_frame = 0;

      if (info->rx_frame_count == 0)
            return 0;

      buf = (RXBUF*)(info->rx_buf + (info->rx_get * info->rx_buf_size));

      status = buf->status;

      /* 07  VFR  1=valid frame
       * 06  RDO  1=data overrun
       * 05  CRC  1=OK, 0=error
       * 04  RAB  1=frame aborted
       */
      if ((status & 0xf0) != 0xA0) {
            if (!(status & BIT7) || (status & BIT4))
                  info->icount.rxabort++;
            else if (status & BIT6)
                  info->icount.rxover++;
            else if (!(status & BIT5)) {
                  info->icount.rxcrc++;
                  if (info->params.crc_type & HDLC_CRC_RETURN_EX)
                        return_frame = 1;
            }
            framesize = 0;
#if SYNCLINK_GENERIC_HDLC
            {
                  struct net_device_stats *stats = hdlc_stats(info->netdev);
                  stats->rx_errors++;
                  stats->rx_frame_errors++;
            }
#endif
      } else
            return_frame = 1;

      if (return_frame)
            framesize = buf->count;

      if (debug_level >= DEBUG_LEVEL_BH)
            printk("%s(%d):rx_get_frame(%s) status=%04X size=%d\n",
                  __FILE__,__LINE__,info->device_name,status,framesize);

      if (debug_level >= DEBUG_LEVEL_DATA)
            trace_block(info, buf->data, framesize, 0);

      if (framesize) {
            if ((info->params.crc_type & HDLC_CRC_RETURN_EX &&
                  framesize+1 > info->max_frame_size) ||
                framesize > info->max_frame_size)
                  info->icount.rxlong++;
            else {
                  if (status & BIT5)
                        info->icount.rxok++;

                  if (info->params.crc_type & HDLC_CRC_RETURN_EX) {
                        *(buf->data + framesize) = status & BIT5 ? RX_OK:RX_CRC_ERROR;
                        ++framesize;
                  }

#if SYNCLINK_GENERIC_HDLC
                  if (info->netcount)
                        hdlcdev_rx(info, buf->data, framesize);
                  else
#endif
                        ldisc_receive_buf(tty, buf->data, info->flag_buf, framesize);
            }
      }

      spin_lock_irqsave(&info->lock,flags);
      buf->status = buf->count = 0;
      info->rx_frame_count--;
      info->rx_get++;
      if (info->rx_get >= info->rx_buf_count)
            info->rx_get = 0;
      spin_unlock_irqrestore(&info->lock,flags);

      return 1;
}

static BOOLEAN register_test(MGSLPC_INFO *info)
{
      static unsigned char patterns[] =
          { 0x00, 0xff, 0xaa, 0x55, 0x69, 0x96, 0x0f };
      static unsigned int count = ARRAY_SIZE(patterns);
      unsigned int i;
      BOOLEAN rc = TRUE;
      unsigned long flags;

      spin_lock_irqsave(&info->lock,flags);
      reset_device(info);

      for (i = 0; i < count; i++) {
            write_reg(info, XAD1, patterns[i]);
            write_reg(info, XAD2, patterns[(i + 1) % count]);
            if ((read_reg(info, XAD1) != patterns[i]) ||
                (read_reg(info, XAD2) != patterns[(i + 1) % count])) {
                  rc = FALSE;
                  break;
            }
      }

      spin_unlock_irqrestore(&info->lock,flags);
      return rc;
}

static BOOLEAN irq_test(MGSLPC_INFO *info)
{
      unsigned long end_time;
      unsigned long flags;

      spin_lock_irqsave(&info->lock,flags);
      reset_device(info);

      info->testing_irq = TRUE;
      hdlc_mode(info);

      info->irq_occurred = FALSE;

      /* init hdlc mode */

      irq_enable(info, CHA, IRQ_TIMER);
      write_reg(info, CHA + TIMR, 0);     /* 512 cycles */
      issue_command(info, CHA, CMD_START_TIMER);

      spin_unlock_irqrestore(&info->lock,flags);

      end_time=100;
      while(end_time-- && !info->irq_occurred) {
            msleep_interruptible(10);
      }

      info->testing_irq = FALSE;

      spin_lock_irqsave(&info->lock,flags);
      reset_device(info);
      spin_unlock_irqrestore(&info->lock,flags);

      return info->irq_occurred ? TRUE : FALSE;
}

static int adapter_test(MGSLPC_INFO *info)
{
      if (!register_test(info)) {
            info->init_error = DiagStatus_AddressFailure;
            printk( "%s(%d):Register test failure for device %s Addr=%04X\n",
                  __FILE__,__LINE__,info->device_name, (unsigned short)(info->io_base) );
            return -ENODEV;
      }

      if (!irq_test(info)) {
            info->init_error = DiagStatus_IrqFailure;
            printk( "%s(%d):Interrupt test failure for device %s IRQ=%d\n",
                  __FILE__,__LINE__,info->device_name, (unsigned short)(info->irq_level) );
            return -ENODEV;
      }

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s(%d):device %s passed diagnostics\n",
                  __FILE__,__LINE__,info->device_name);
      return 0;
}

static void trace_block(MGSLPC_INFO *info,const char* data, int count, int xmit)
{
      int i;
      int linecount;
      if (xmit)
            printk("%s tx data:\n",info->device_name);
      else
            printk("%s rx data:\n",info->device_name);

      while(count) {
            if (count > 16)
                  linecount = 16;
            else
                  linecount = count;

            for(i=0;i<linecount;i++)
                  printk("%02X ",(unsigned char)data[i]);
            for(;i<17;i++)
                  printk("   ");
            for(i=0;i<linecount;i++) {
                  if (data[i]>=040 && data[i]<=0176)
                        printk("%c",data[i]);
                  else
                        printk(".");
            }
            printk("\n");

            data  += linecount;
            count -= linecount;
      }
}

/* HDLC frame time out
 * update stats and do tx completion processing
 */
static void tx_timeout(unsigned long context)
{
      MGSLPC_INFO *info = (MGSLPC_INFO*)context;
      unsigned long flags;

      if ( debug_level >= DEBUG_LEVEL_INFO )
            printk( "%s(%d):tx_timeout(%s)\n",
                  __FILE__,__LINE__,info->device_name);
      if(info->tx_active &&
         info->params.mode == MGSL_MODE_HDLC) {
            info->icount.txtimeout++;
      }
      spin_lock_irqsave(&info->lock,flags);
      info->tx_active = 0;
      info->tx_count = info->tx_put = info->tx_get = 0;

      spin_unlock_irqrestore(&info->lock,flags);

#if SYNCLINK_GENERIC_HDLC
      if (info->netcount)
            hdlcdev_tx_done(info);
      else
#endif
            bh_transmit(info);
}

#if SYNCLINK_GENERIC_HDLC

/**
 * called by generic HDLC layer when protocol selected (PPP, frame relay, etc.)
 * set encoding and frame check sequence (FCS) options
 *
 * dev       pointer to network device structure
 * encoding  serial encoding setting
 * parity    FCS setting
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_attach(struct net_device *dev, unsigned short encoding,
                    unsigned short parity)
{
      MGSLPC_INFO *info = dev_to_port(dev);
      unsigned char  new_encoding;
      unsigned short new_crctype;

      /* return error if TTY interface open */
      if (info->count)
            return -EBUSY;

      switch (encoding)
      {
      case ENCODING_NRZ:        new_encoding = HDLC_ENCODING_NRZ; break;
      case ENCODING_NRZI:       new_encoding = HDLC_ENCODING_NRZI_SPACE; break;
      case ENCODING_FM_MARK:    new_encoding = HDLC_ENCODING_BIPHASE_MARK; break;
      case ENCODING_FM_SPACE:   new_encoding = HDLC_ENCODING_BIPHASE_SPACE; break;
      case ENCODING_MANCHESTER: new_encoding = HDLC_ENCODING_BIPHASE_LEVEL; break;
      default: return -EINVAL;
      }

      switch (parity)
      {
      case PARITY_NONE:            new_crctype = HDLC_CRC_NONE; break;
      case PARITY_CRC16_PR1_CCITT: new_crctype = HDLC_CRC_16_CCITT; break;
      case PARITY_CRC32_PR1_CCITT: new_crctype = HDLC_CRC_32_CCITT; break;
      default: return -EINVAL;
      }

      info->params.encoding = new_encoding;
      info->params.crc_type = new_crctype;

      /* if network interface up, reprogram hardware */
      if (info->netcount)
            mgslpc_program_hw(info);

      return 0;
}

/**
 * called by generic HDLC layer to send frame
 *
 * skb  socket buffer containing HDLC frame
 * dev  pointer to network device structure
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_xmit(struct sk_buff *skb, struct net_device *dev)
{
      MGSLPC_INFO *info = dev_to_port(dev);
      struct net_device_stats *stats = hdlc_stats(dev);
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk(KERN_INFO "%s:hdlc_xmit(%s)\n",__FILE__,dev->name);

      /* stop sending until this frame completes */
      netif_stop_queue(dev);

      /* copy data to device buffers */
      skb_copy_from_linear_data(skb, info->tx_buf, skb->len);
      info->tx_get = 0;
      info->tx_put = info->tx_count = skb->len;

      /* update network statistics */
      stats->tx_packets++;
      stats->tx_bytes += skb->len;

      /* done with socket buffer, so free it */
      dev_kfree_skb(skb);

      /* save start time for transmit timeout detection */
      dev->trans_start = jiffies;

      /* start hardware transmitter if necessary */
      spin_lock_irqsave(&info->lock,flags);
      if (!info->tx_active)
            tx_start(info);
      spin_unlock_irqrestore(&info->lock,flags);

      return 0;
}

/**
 * called by network layer when interface enabled
 * claim resources and initialize hardware
 *
 * dev  pointer to network device structure
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_open(struct net_device *dev)
{
      MGSLPC_INFO *info = dev_to_port(dev);
      int rc;
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s:hdlcdev_open(%s)\n",__FILE__,dev->name);

      /* generic HDLC layer open processing */
      if ((rc = hdlc_open(dev)))
            return rc;

      /* arbitrate between network and tty opens */
      spin_lock_irqsave(&info->netlock, flags);
      if (info->count != 0 || info->netcount != 0) {
            printk(KERN_WARNING "%s: hdlc_open returning busy\n", dev->name);
            spin_unlock_irqrestore(&info->netlock, flags);
            return -EBUSY;
      }
      info->netcount=1;
      spin_unlock_irqrestore(&info->netlock, flags);

      /* claim resources and init adapter */
      if ((rc = startup(info)) != 0) {
            spin_lock_irqsave(&info->netlock, flags);
            info->netcount=0;
            spin_unlock_irqrestore(&info->netlock, flags);
            return rc;
      }

      /* assert DTR and RTS, apply hardware settings */
      info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
      mgslpc_program_hw(info);

      /* enable network layer transmit */
      dev->trans_start = jiffies;
      netif_start_queue(dev);

      /* inform generic HDLC layer of current DCD status */
      spin_lock_irqsave(&info->lock, flags);
      get_signals(info);
      spin_unlock_irqrestore(&info->lock, flags);
      if (info->serial_signals & SerialSignal_DCD)
            netif_carrier_on(dev);
      else
            netif_carrier_off(dev);
      return 0;
}

/**
 * called by network layer when interface is disabled
 * shutdown hardware and release resources
 *
 * dev  pointer to network device structure
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_close(struct net_device *dev)
{
      MGSLPC_INFO *info = dev_to_port(dev);
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s:hdlcdev_close(%s)\n",__FILE__,dev->name);

      netif_stop_queue(dev);

      /* shutdown adapter and release resources */
      shutdown(info);

      hdlc_close(dev);

      spin_lock_irqsave(&info->netlock, flags);
      info->netcount=0;
      spin_unlock_irqrestore(&info->netlock, flags);

      return 0;
}

/**
 * called by network layer to process IOCTL call to network device
 *
 * dev  pointer to network device structure
 * ifr  pointer to network interface request structure
 * cmd  IOCTL command code
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
      const size_t size = sizeof(sync_serial_settings);
      sync_serial_settings new_line;
      sync_serial_settings __user *line = ifr->ifr_settings.ifs_ifsu.sync;
      MGSLPC_INFO *info = dev_to_port(dev);
      unsigned int flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("%s:hdlcdev_ioctl(%s)\n",__FILE__,dev->name);

      /* return error if TTY interface open */
      if (info->count)
            return -EBUSY;

      if (cmd != SIOCWANDEV)
            return hdlc_ioctl(dev, ifr, cmd);

      switch(ifr->ifr_settings.type) {
      case IF_GET_IFACE: /* return current sync_serial_settings */

            ifr->ifr_settings.type = IF_IFACE_SYNC_SERIAL;
            if (ifr->ifr_settings.size < size) {
                  ifr->ifr_settings.size = size; /* data size wanted */
                  return -ENOBUFS;
            }

            flags = info->params.flags & (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
                                    HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
                                    HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
                                    HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN);

            switch (flags){
            case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_TXCPIN): new_line.clock_type = CLOCK_EXT; break;
            case (HDLC_FLAG_RXC_BRG    | HDLC_FLAG_TXC_BRG):    new_line.clock_type = CLOCK_INT; break;
            case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_BRG):    new_line.clock_type = CLOCK_TXINT; break;
            case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_RXCPIN): new_line.clock_type = CLOCK_TXFROMRX; break;
            default: new_line.clock_type = CLOCK_DEFAULT;
            }

            new_line.clock_rate = info->params.clock_speed;
            new_line.loopback   = info->params.loopback ? 1:0;

            if (copy_to_user(line, &new_line, size))
                  return -EFAULT;
            return 0;

      case IF_IFACE_SYNC_SERIAL: /* set sync_serial_settings */

            if(!capable(CAP_NET_ADMIN))
                  return -EPERM;
            if (copy_from_user(&new_line, line, size))
                  return -EFAULT;

            switch (new_line.clock_type)
            {
            case CLOCK_EXT:      flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_TXCPIN; break;
            case CLOCK_TXFROMRX: flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_RXCPIN; break;
            case CLOCK_INT:      flags = HDLC_FLAG_RXC_BRG    | HDLC_FLAG_TXC_BRG;    break;
            case CLOCK_TXINT:    flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_BRG;    break;
            case CLOCK_DEFAULT:  flags = info->params.flags &
                                   (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
                                    HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
                                    HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
                                    HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN); break;
            default: return -EINVAL;
            }

            if (new_line.loopback != 0 && new_line.loopback != 1)
                  return -EINVAL;

            info->params.flags &= ~(HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
                              HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
                              HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
                              HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN);
            info->params.flags |= flags;

            info->params.loopback = new_line.loopback;

            if (flags & (HDLC_FLAG_RXC_BRG | HDLC_FLAG_TXC_BRG))
                  info->params.clock_speed = new_line.clock_rate;
            else
                  info->params.clock_speed = 0;

            /* if network interface up, reprogram hardware */
            if (info->netcount)
                  mgslpc_program_hw(info);
            return 0;

      default:
            return hdlc_ioctl(dev, ifr, cmd);
      }
}

/**
 * called by network layer when transmit timeout is detected
 *
 * dev  pointer to network device structure
 */
static void hdlcdev_tx_timeout(struct net_device *dev)
{
      MGSLPC_INFO *info = dev_to_port(dev);
      struct net_device_stats *stats = hdlc_stats(dev);
      unsigned long flags;

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("hdlcdev_tx_timeout(%s)\n",dev->name);

      stats->tx_errors++;
      stats->tx_aborted_errors++;

      spin_lock_irqsave(&info->lock,flags);
      tx_stop(info);
      spin_unlock_irqrestore(&info->lock,flags);

      netif_wake_queue(dev);
}

/**
 * called by device driver when transmit completes
 * reenable network layer transmit if stopped
 *
 * info  pointer to device instance information
 */
static void hdlcdev_tx_done(MGSLPC_INFO *info)
{
      if (netif_queue_stopped(info->netdev))
            netif_wake_queue(info->netdev);
}

/**
 * called by device driver when frame received
 * pass frame to network layer
 *
 * info  pointer to device instance information
 * buf   pointer to buffer contianing frame data
 * size  count of data bytes in buf
 */
static void hdlcdev_rx(MGSLPC_INFO *info, char *buf, int size)
{
      struct sk_buff *skb = dev_alloc_skb(size);
      struct net_device *dev = info->netdev;
      struct net_device_stats *stats = hdlc_stats(dev);

      if (debug_level >= DEBUG_LEVEL_INFO)
            printk("hdlcdev_rx(%s)\n",dev->name);

      if (skb == NULL) {
            printk(KERN_NOTICE "%s: can't alloc skb, dropping packet\n", dev->name);
            stats->rx_dropped++;
            return;
      }

      memcpy(skb_put(skb, size),buf,size);

      skb->protocol = hdlc_type_trans(skb, info->netdev);

      stats->rx_packets++;
      stats->rx_bytes += size;

      netif_rx(skb);

      info->netdev->last_rx = jiffies;
}

/**
 * called by device driver when adding device instance
 * do generic HDLC initialization
 *
 * info  pointer to device instance information
 *
 * returns 0 if success, otherwise error code
 */
static int hdlcdev_init(MGSLPC_INFO *info)
{
      int rc;
      struct net_device *dev;
      hdlc_device *hdlc;

      /* allocate and initialize network and HDLC layer objects */

      if (!(dev = alloc_hdlcdev(info))) {
            printk(KERN_ERR "%s:hdlc device allocation failure\n",__FILE__);
            return -ENOMEM;
      }

      /* for network layer reporting purposes only */
      dev->base_addr = info->io_base;
      dev->irq       = info->irq_level;

      /* network layer callbacks and settings */
      dev->do_ioctl       = hdlcdev_ioctl;
      dev->open           = hdlcdev_open;
      dev->stop           = hdlcdev_close;
      dev->tx_timeout     = hdlcdev_tx_timeout;
      dev->watchdog_timeo = 10*HZ;
      dev->tx_queue_len   = 50;

      /* generic HDLC layer callbacks and settings */
      hdlc         = dev_to_hdlc(dev);
      hdlc->attach = hdlcdev_attach;
      hdlc->xmit   = hdlcdev_xmit;

      /* register objects with HDLC layer */
      if ((rc = register_hdlc_device(dev))) {
            printk(KERN_WARNING "%s:unable to register hdlc device\n",__FILE__);
            free_netdev(dev);
            return rc;
      }

      info->netdev = dev;
      return 0;
}

/**
 * called by device driver when removing device instance
 * do generic HDLC cleanup
 *
 * info  pointer to device instance information
 */
static void hdlcdev_exit(MGSLPC_INFO *info)
{
      unregister_hdlc_device(info->netdev);
      free_netdev(info->netdev);
      info->netdev = NULL;
}

#endif /* CONFIG_HDLC */


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