text: /*
   * 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/seq_file.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 <linux/synclink.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/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 <linux/uaccess.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 {
  	struct tty_port		port;
  	void *if_ptr;	/* General purpose pointer (used by SPPP) */
  	int			magic;
  	int			line;
  
  	struct mgsl_icount	icount;
  
  	int			timeout;
  	int			x_char;		/* xon/xoff character */
  	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	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;
  
  	bool bh_running;
  	bool 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;
  
  	bool rx_enabled;
  	bool rx_overflow;
  
  	bool tx_enabled;
  	bool tx_active;
  	bool 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 */
  
  	bool irq_occurred;		/* for diagnostics use */
  	char testing_irq;
  	unsigned int init_error;	/* startup error (DIAGS)	*/
  
  	char *flag_buf;
  	bool drop_rts_on_tx_done;
  
  	struct	_input_signal_events	input_signal_events;
  
  	/* PCMCIA support */
  	struct pcmcia_device	*p_dev;
  	int		      stop;
  
  	/* SPPP/Cisco HDLC device parts */
  	int netcount;
  	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, struct tty_struct *tty);
  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(struct timer_list *t);
  
  static int carrier_raised(struct tty_port *port);
  static void dtr_rts(struct tty_port *port, int onoff);
  
  #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 bool register_test(MGSLPC_INFO *info);
  static bool 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 int mgslpc_add_device(MGSLPC_INFO *info);
  static void mgslpc_remove_device(MGSLPC_INFO *info);
  
  static bool rx_get_frame(MGSLPC_INFO *info, struct tty_struct *tty);
  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, struct tty_struct *tty);
  static void bh_status(MGSLPC_INFO *info);
  
  /*
   * ioctl handlers
   */
  static int tiocmget(struct tty_struct *tty);
  static int tiocmset(struct tty_struct *tty,
  					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, struct tty_struct *tty);
  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, struct tty_struct *tty);
  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 bool break_on_load;
  
  /*
   * 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,};
  
  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_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, struct tty_struct *tty);
  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_receive_buf  - pass receive data to line discipline
   */
  
  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->ops->receive_buf)
  			ld->ops->receive_buf(tty, data, flags, count);
  		tty_ldisc_deref(ld);
  	}
  }
  
  static const struct tty_port_operations mgslpc_port_ops = {
  	.carrier_raised = carrier_raised,
  	.dtr_rts = dtr_rts
  };
  
  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;
  	tty_port_init(&info->port);
  	info->port.ops = &mgslpc_port_ops;
  	INIT_WORK(&info->task, bh_handler);
  	info->max_frame_size = 4096;
  	info->port.close_delay = 5*HZ/10;
  	info->port.closing_wait = 30*HZ;
  	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 */
  
  	ret = mgslpc_config(link);
  	if (ret != 0)
  		goto failed;
  
  	ret = mgslpc_add_device(info);
  	if (ret != 0)
  		goto failed_release;
  
  	return 0;
  
  failed_release:
  	mgslpc_release((u_long)link);
  failed:
  	tty_port_destroy(&info->port);
  	kfree(info);
  	return ret;
  }
  
  /* Card has been inserted.
   */
  
  static int mgslpc_ioprobe(struct pcmcia_device *p_dev, void *priv_data)
  {
  	return pcmcia_request_io(p_dev);
  }
  
  static int mgslpc_config(struct pcmcia_device *link)
  {
  	MGSLPC_INFO *info = link->priv;
  	int ret;
  
  	if (debug_level >= DEBUG_LEVEL_INFO)
  		printk("mgslpc_config(0x%p)\n", link);
  
  	link->config_flags |= CONF_ENABLE_IRQ | CONF_AUTO_SET_IO;
  
  	ret = pcmcia_loop_config(link, mgslpc_ioprobe, NULL);
  	if (ret != 0)
  		goto failed;
  
  	link->config_index = 8;
  	link->config_regs = PRESENT_OPTION;
  
  	ret = pcmcia_request_irq(link, mgslpc_isr);
  	if (ret)
  		goto failed;
  	ret = pcmcia_enable_device(link);
  	if (ret)
  		goto failed;
  
  	info->io_base = link->resource[0]->start;
  	info->irq_level = link->irq;
  	return 0;
  
  failed:
  	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 bool 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 true;
  	}
  	if (info->magic != MGSLPC_MAGIC) {
  		printk(badmagic, name, routine);
  		return true;
  	}
  #else
  	if (!info)
  		return true;
  #endif
  	return false;
  }
  
  
  #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 bool 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, tty);
  	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 = false;
  		info->bh_requested = false;
  	}
  
  	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);
  	struct tty_struct *tty;
  	int action;
  
  	if (debug_level >= DEBUG_LEVEL_BH)
  		printk("%s(%d):bh_handler(%s) entry\n",
  			__FILE__,__LINE__,info->device_name);
  
  	info->bh_running = true;
  	tty = tty_port_tty_get(&info->port);
  
  	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, tty));
  			break;
  		case BH_TRANSMIT:
  			bh_transmit(info, tty);
  			break;
  		case BH_STATUS:
  			bh_status(info);
  			break;
  		default:
  			/* unknown work item ID */
  			printk("Unknown work item ID=%08X!\n", action);
  			break;
  		}
  	}
  
  	tty_kref_put(tty);
  	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)
  {
  	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 = true;
  		info->icount.buf_overrun++;
  		return;
  	}
  
  	if (eom) {
  		/* end of frame, get FIFO count from RBCL register */
  		fifo_count = (unsigned char)(read_reg(info, CHA+RBCL) & 0x1f);
  		if (fifo_count == 0)
  			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)
  {
  	struct tty_port *port = &info->port;
  	unsigned char data, status, flag;
  	int fifo_count;
  	int work = 0;
  	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(port, 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(port, 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(port);
  }
  
  
  static void tx_done(MGSLPC_INFO *info, struct tty_struct *tty)
  {
  	if (!info->tx_active)
  		return;
  
  	info->tx_active = false;
  	info->tx_aborting = false;
  
  	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 = false;
  	}
  
  #if SYNCLINK_GENERIC_HDLC
  	if (info->netcount)
  		hdlcdev_tx_done(info);
  	else
  #endif
  	{
  		if (tty && (tty->stopped || tty->hw_stopped)) {
  			tx_stop(info);
  			return;
  		}
  		info->pending_bh |= BH_TRANSMIT;
  	}
  }
  
  static void tx_ready(MGSLPC_INFO *info, struct tty_struct *tty)
  {
  	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 (tty && (tty->stopped || tty->hw_stopped)) {
  			tx_stop(info);
  			return;
  		}
  		if (!info->tx_count)
  			info->tx_active = false;
  	}
  
  	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, struct tty_struct *tty)
  {
  	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 (tty && tty_port_cts_enabled(&info->port)) {
  		if (tty->hw_stopped) {
  			if (info->serial_signals & SerialSignal_CTS) {
  				if (debug_level >= DEBUG_LEVEL_ISR)
  					printk("CTS tx start...");
  				tty->hw_stopped = 0;
  				tx_start(info, tty);
  				info->pending_bh |= BH_TRANSMIT;
  				return;
  			}
  		} else {
  			if (!(info->serial_signals & SerialSignal_CTS)) {
  				if (debug_level >= DEBUG_LEVEL_ISR)
  					printk("CTS tx stop...");
  				tty->hw_stopped = 1;
  				tx_stop(info);
  			}
  		}
  	}
  	info->pending_bh |= BH_STATUS;
  }
  
  static void dcd_change(MGSLPC_INFO *info, struct tty_struct *tty)
  {
  	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 (tty_port_check_carrier(&info->port)) {
  		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->port.open_wait);
  		else {
  			if (debug_level >= DEBUG_LEVEL_ISR)
  				printk("doing serial hangup...");
  			if (tty)
  				tty_hangup(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 dummy, void *dev_id)
  {
  	MGSLPC_INFO *info = dev_id;
  	struct tty_struct *tty;
  	unsigned short isr;
  	unsigned char gis, pis;
  	int count=0;
  
  	if (debug_level >= DEBUG_LEVEL_ISR)
  		printk("mgslpc_isr(%d) entry.\n", info->irq_level);
  
  	if (!(info->p_dev->_locked))
  		return IRQ_HANDLED;
  
  	tty = tty_port_tty_get(&info->port);
  
  	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, tty);
  			if (isr & IRQ_CTS)
  				cts_change(info, tty);
  		}
  		if (gis & (BIT3 | BIT2))
  		{
  			isr = read_reg16(info, CHA + ISR);
  			if (isr & IRQ_TIMER) {
  				info->irq_occurred = true;
  				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->port.flags & ASYNC_SAK)
  					do_SAK(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, tty);
  			}
  			else if (isr & IRQ_ALLSENT) {
  				info->icount.txok++;
  				tx_done(info, tty);
  			}
  			else if (isr & IRQ_TXFIFO)
  				tx_ready(info, tty);
  		}
  		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 = true;
  	}
  
  	spin_unlock(&info->lock);
  	tty_kref_put(tty);
  
  	if (debug_level >= DEBUG_LEVEL_ISR)
  		printk("%s(%d):mgslpc_isr(%d)exit.\n",
  		       __FILE__, __LINE__, info->irq_level);
  
  	return IRQ_HANDLED;
  }
  
  /* Initialize and start device.
   */
  static int startup(MGSLPC_INFO * info, struct tty_struct *tty)
  {
  	int retval = 0;
  
  	if (debug_level >= DEBUG_LEVEL_INFO)
  		printk("%s(%d):startup(%s)\n", __FILE__, __LINE__, info->device_name);
  
  	if (tty_port_initialized(&info->port))
  		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));
  
  	timer_setup(&info->tx_timer, tx_timeout, 0);
  
  	/* Allocate and claim adapter resources */
  	retval = claim_resources(info);
  
  	/* perform existence check and diagnostics */
  	if (!retval)
  		retval = adapter_test(info);
  
  	if (retval) {
  		if (capable(CAP_SYS_ADMIN) && tty)
  			set_bit(TTY_IO_ERROR, &tty->flags);
  		release_resources(info);
  		return retval;
  	}
  
  	/* program hardware for current parameters */
  	mgslpc_change_params(info, tty);
  
  	if (tty)
  		clear_bit(TTY_IO_ERROR, &tty->flags);
  
  	tty_port_set_initialized(&info->port, 1);
  
  	return 0;
  }
  
  /* Called by mgslpc_close() and mgslpc_hangup() to shutdown hardware
   */
  static void shutdown(MGSLPC_INFO * info, struct tty_struct *tty)
  {
  	unsigned long flags;
  
  	if (!tty_port_initialized(&info->port))
  		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 (!tty || C_HUPCL(tty)) {
  		info->serial_signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
  		set_signals(info);
  	}
  
  	spin_unlock_irqrestore(&info->lock, flags);
  
  	release_resources(info);
  
  	if (tty)
  		set_bit(TTY_IO_ERROR, &tty->flags);
  
  	tty_port_set_initialized(&info->port, 0);
  }
  
  static void mgslpc_program_hw(MGSLPC_INFO *info, struct tty_struct *tty)
  {
  	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 || (tty && C_CREAD(tty)))
  		rx_start(info);
  
  	spin_unlock_irqrestore(&info->lock, flags);
  }
  
  /* Reconfigure adapter based on new parameters
   */
  static void mgslpc_change_params(MGSLPC_INFO *info, struct tty_struct *tty)
  {
  	unsigned cflag;
  	int bits_per_char;
  
  	if (!tty)
  		return;
  
  	if (debug_level >= DEBUG_LEVEL_INFO)
  		printk("%s(%d):mgslpc_change_params(%s)\n",
  			 __FILE__, __LINE__, info->device_name);
  
  	cflag = tty->termios.c_cflag;
  
  	/* if B0 rate (hangup) specified then negate RTS and DTR */
  	/* otherwise assert RTS and DTR */
  	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(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 */
  
  	tty_port_set_cts_flow(&info->port, cflag & CRTSCTS);
  	tty_port_set_check_carrier(&info->port, ~cflag & CLOCAL);
  
  	/* process tty input control flags */
  
  	info->read_status_mask = 0;
  	if (I_INPCK(tty))
  		info->read_status_mask |= BIT7 | BIT6;
  	if (I_IGNPAR(tty))
  		info->ignore_status_mask |= BIT7 | BIT6;
  
  	mgslpc_program_hw(info, tty);
  }
  
  /* Add a character to the transmit buffer
   */
  static int 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 0;
  
  	if (!info->tx_buf)
  		return 0;
  
  	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);
  	return 1;
  }
  
  /* 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, tty);
  	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, tty);
  		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, tty);
  		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 (C_CRTSCTS(tty)) {
  		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 (C_CRTSCTS(tty)) {
  		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, struct tty_struct *tty)
  {
  	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, tty);
  
  	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, struct tty_struct *tty)
  {
  	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, tty);
  	} 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)
  {
  	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,
  		    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 int 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 -EINVAL;
  
  	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);
  	return 0;
  }
  
  static int mgslpc_get_icount(struct tty_struct *tty,
  				struct serial_icounter_struct *icount)
  {
  	MGSLPC_INFO * info = (MGSLPC_INFO *)tty->driver_data;
  	struct mgsl_icount cnow;	/* kernel counter temps */
  	unsigned long flags;
  
  	spin_lock_irqsave(&info->lock, flags);
  	cnow = info->icount;
  	spin_unlock_irqrestore(&info->lock, flags);
  
  	icount->cts = cnow.cts;
  	icount->dsr = cnow.dsr;
  	icount->rng = cnow.rng;
  	icount->dcd = cnow.dcd;
  	icount->rx = cnow.rx;
  	icount->tx = cnow.tx;
  	icount->frame = cnow.frame;
  	icount->overrun = cnow.overrun;
  	icount->parity = cnow.parity;
  	icount->brk = cnow.brk;
  	icount->buf_overrun = cnow.buf_overrun;
  
  	return 0;
  }
  
  /* Service an IOCTL request
   *
   * Arguments:
   *
   *	tty	pointer to tty instance data
   *	cmd	IOCTL command code
   *	arg	command argument/context
   *
   * Return Value:	0 if success, otherwise error code
   */
  static int mgslpc_ioctl(struct tty_struct *tty,
  			unsigned int cmd, unsigned long arg)
  {
  	MGSLPC_INFO * info = (MGSLPC_INFO *)tty->driver_data;
  	void __user *argp = (void __user *)arg;
  
  	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)) {
  		if (tty_io_error(tty))
  		    return -EIO;
  	}
  
  	switch (cmd) {
  	case MGSL_IOCGPARAMS:
  		return get_params(info, argp);
  	case MGSL_IOCSPARAMS:
  		return set_params(info, argp, tty);
  	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, tty);
  	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);
  	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, tty);
  
  	/* Handle transition to B0 status */
  	if ((old_termios->c_cflag & CBAUD) && !C_BAUD(tty)) {
  		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) && C_BAUD(tty)) {
  		info->serial_signals |= SerialSignal_DTR;
  		if (!C_CRTSCTS(tty) || !tty_throttled(tty))
  			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 && !C_CRTSCTS(tty)) {
  		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;
  	struct tty_port *port = &info->port;
  
  	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, port->count);
  
  	if (tty_port_close_start(port, tty, filp) == 0)
  		goto cleanup;
  
  	if (tty_port_initialized(port))
  		mgslpc_wait_until_sent(tty, info->timeout);
  
  	mgslpc_flush_buffer(tty);
  
  	tty_ldisc_flush(tty);
  	shutdown(info, tty);
  	
  	tty_port_close_end(port, tty);
  	tty_port_tty_set(port, NULL);
  cleanup:
  	if (debug_level >= DEBUG_LEVEL_INFO)
  		printk("%s(%d):mgslpc_close(%s) exit, count=%d\n", __FILE__, __LINE__,
  			tty->driver->name, port->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 (!tty_port_initialized(&info->port))
  		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, tty);
  	tty_port_hangup(&info->port);
  }
  
  static int carrier_raised(struct tty_port *port)
  {
  	MGSLPC_INFO *info = container_of(port, MGSLPC_INFO, port);
  	unsigned long flags;
  
  	spin_lock_irqsave(&info->lock, flags);
  	get_signals(info);
  	spin_unlock_irqrestore(&info->lock, flags);
  
  	if (info->serial_signals & SerialSignal_DCD)
  		return 1;
  	return 0;
  }
  
  static void dtr_rts(struct tty_port *port, int onoff)
  {
  	MGSLPC_INFO *info = container_of(port, MGSLPC_INFO, port);
  	unsigned long flags;
  
  	spin_lock_irqsave(&info->lock, flags);
  	if (onoff)
  		info->serial_signals |= SerialSignal_RTS | SerialSignal_DTR;
  	else
  		info->serial_signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
  	set_signals(info);
  	spin_unlock_irqrestore(&info->lock, flags);
  }
  
  
  static int mgslpc_open(struct tty_struct *tty, struct file * filp)
  {
  	MGSLPC_INFO	*info;
  	struct tty_port *port;
  	int		retval, line;
  	unsigned long	flags;
  
  	/* verify range of specified line number */
  	line = tty->index;
  	if (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;
  
  	port = &info->port;
  	tty->driver_data = info;
  	tty_port_tty_set(port, tty);
  
  	if (debug_level >= DEBUG_LEVEL_INFO)
  		printk("%s(%d):mgslpc_open(%s), old ref count = %d\n",
  			 __FILE__, __LINE__, tty->driver->name, port->count);
  
  	port->low_latency = (port->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;
  	}
  	spin_lock(&port->lock);
  	port->count++;
  	spin_unlock(&port->lock);
  	spin_unlock_irqrestore(&info->netlock, flags);
  
  	if (port->count == 1) {
  		/* 1st open on this device, init hardware */
  		retval = startup(info, tty);
  		if (retval < 0)
  			goto cleanup;
  	}
  
  	retval = tty_port_block_til_ready(&info->port, tty, filp);
  	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:
  	return retval;
  }
  
  /*
   * /proc fs routines....
   */
  
  static inline void line_info(struct seq_file *m, MGSLPC_INFO *info)
  {
  	char	stat_buf[30];
  	unsigned long flags;
  
  	seq_printf(m, "%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) {
  		seq_printf(m, " HDLC txok:%d rxok:%d",
  			      info->icount.txok, info->icount.rxok);
  		if (info->icount.txunder)
  			seq_printf(m, " txunder:%d", info->icount.txunder);
  		if (info->icount.txabort)
  			seq_printf(m, " txabort:%d", info->icount.txabort);
  		if (info->icount.rxshort)
  			seq_printf(m, " rxshort:%d", info->icount.rxshort);
  		if (info->icount.rxlong)
  			seq_printf(m, " rxlong:%d", info->icount.rxlong);
  		if (info->icount.rxover)
  			seq_printf(m, " rxover:%d", info->icount.rxover);
  		if (info->icount.rxcrc)
  			seq_printf(m, " rxcrc:%d", info->icount.rxcrc);
  	} else {
  		seq_printf(m, " ASYNC tx:%d rx:%d",
  			      info->icount.tx, info->icount.rx);
  		if (info->icount.frame)
  			seq_printf(m, " fe:%d", info->icount.frame);
  		if (info->icount.parity)
  			seq_printf(m, " pe:%d", info->icount.parity);
  		if (info->icount.brk)
  			seq_printf(m, " brk:%d", info->icount.brk);
  		if (info->icount.overrun)
  			seq_printf(m, " oe:%d", info->icount.overrun);
  	}
  
  	/* Append serial signal status to end */
  	seq_printf(m, " %s\n", stat_buf+1);
  
  	seq_printf(m, "txactive=%d bh_req=%d bh_run=%d pending_bh=%x\n",
  		       info->tx_active,info->bh_requested,info->bh_running,
  		       info->pending_bh);
  }
  
  /* Called to print information about devices
   */
  static int mgslpc_proc_show(struct seq_file *m, void *v)
  {
  	MGSLPC_INFO *info;
  
  	seq_printf(m, "synclink driver:%s\n", driver_version);
  
  	info = mgslpc_device_list;
  	while (info) {
  		line_info(m, info);
  		info = info->next_device;
  	}
  	return 0;
  }
  
  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;
  
  	/* unused flag buffer to satisfy receive_buf calling interface */
  	info->flag_buf = kzalloc(info->max_frame_size, GFP_KERNEL);
  	if (!info->flag_buf) {
  		kfree(info->rx_buf);
  		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;
  	kfree(info->flag_buf);
  	info->flag_buf = NULL;
  }
  
  static int claim_resources(MGSLPC_INFO *info)
  {
  	if (rx_alloc_buffers(info) < 0) {
  		printk("Can't 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 int mgslpc_add_device(MGSLPC_INFO *info)
  {
  	MGSLPC_INFO *current_dev = NULL;
  	struct device *tty_dev;
  	int ret;
  
  	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];
  	}
  
  	mgslpc_device_count++;
  
  	if (!mgslpc_device_list)
  		mgslpc_device_list = info;
  	else {
  		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
  	ret = hdlcdev_init(info);
  	if (ret != 0)
  		goto failed;
  #endif
  
  	tty_dev = tty_port_register_device(&info->port, serial_driver, info->line,
  			&info->p_dev->dev);
  	if (IS_ERR(tty_dev)) {
  		ret = PTR_ERR(tty_dev);
  #if SYNCLINK_GENERIC_HDLC
  		hdlcdev_exit(info);
  #endif
  		goto failed;
  	}
  
  	return 0;
  
  failed:
  	if (current_dev)
  		current_dev->next_device = NULL;
  	else
  		mgslpc_device_list = NULL;
  	mgslpc_device_count--;
  	return ret;
  }
  
  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;
  			tty_unregister_device(serial_driver, info->line);
  #if SYNCLINK_GENERIC_HDLC
  			hdlcdev_exit(info);
  #endif
  			release_resources(info);
  			tty_port_destroy(&info->port);
  			kfree(info);
  			mgslpc_device_count--;
  			return;
  		}
  		last = info;
  		info = info->next_device;
  	}
  }
  
  static const 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,
  	.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,
  	.set_termios = mgslpc_set_termios,
  	.stop = tx_pause,
  	.start = tx_release,
  	.hangup = mgslpc_hangup,
  	.tiocmget = tiocmget,
  	.tiocmset = tiocmset,
  	.get_icount = mgslpc_get_icount,
  	.proc_show = mgslpc_proc_show,
  };
  
  static int __init synclink_cs_init(void)
  {
  	int rc;
  
  	if (break_on_load) {
  		mgslpc_get_text_ptr();
  		BREAKPOINT();
  	}
  
  	serial_driver = tty_alloc_driver(MAX_DEVICE_COUNT,
  			TTY_DRIVER_REAL_RAW |
  			TTY_DRIVER_DYNAMIC_DEV);
  	if (IS_ERR(serial_driver)) {
  		rc = PTR_ERR(serial_driver);
  		goto err;
  	}
  
  	/* Initialize the tty_driver structure */
  	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;
  	tty_set_operations(serial_driver, &mgslpc_ops);
  
  	rc = tty_register_driver(serial_driver);
  	if (rc < 0) {
  		printk(KERN_ERR "%s(%d):Couldn't register serial driver\n",
  				__FILE__, __LINE__);
  		goto err_put_tty;
  	}
  
  	rc = pcmcia_register_driver(&mgslpc_driver);
  	if (rc < 0)
  		goto err_unreg_tty;
  
  	printk(KERN_INFO "%s %s, tty major#%d\n", driver_name, driver_version,
  			serial_driver->major);
  
  	return 0;
  err_unreg_tty:
  	tty_unregister_driver(serial_driver);
  err_put_tty:
  	put_tty_driver(serial_driver);
  err:
  	return rc;
  }
  
  static void __exit synclink_cs_exit(void)
  {
  	pcmcia_unregister_driver(&mgslpc_driver);
  	tty_unregister_driver(serial_driver);
  	put_tty_driver(serial_driver);
  }
  
  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 = false;
  	info->rx_overflow = false;
  }
  
  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 = false;
  	info->rx_overflow = false;
  
  	/* MODE:03 RAC Receiver Active, 1=active */
  	set_reg_bits(info, CHA + MODE, BIT3);
  
  	info->rx_enabled = true;
  }
  
  static void tx_start(MGSLPC_INFO *info, struct tty_struct *tty)
  {
  	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 = false;
  
  		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 = true;
  			}
  		}
  
  		if (info->params.mode == MGSL_MODE_ASYNC) {
  			if (!info->tx_active) {
  				info->tx_active = true;
  				tx_ready(info, tty);
  			}
  		} else {
  			info->tx_active = true;
  			tx_ready(info, tty);
  			mod_timer(&info->tx_timer, jiffies +
  					msecs_to_jiffies(5000));
  		}
  	}
  
  	if (!info->tx_enabled)
  		info->tx_enabled = true;
  }
  
  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 = false;
  	info->tx_active = false;
  }
  
  /* 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 RTS and DTR */
  	info->serial_signals &= SerialSignal_RTS | SerialSignal_DTR;
  
  	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 RTS and DTR 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 true if frame returned, otherwise false
   */
  static bool rx_get_frame(MGSLPC_INFO *info, struct tty_struct *tty)
  {
  	unsigned short status;
  	RXBUF *buf;
  	unsigned int framesize = 0;
  	unsigned long flags;
  	bool return_frame = false;
  
  	if (info->rx_frame_count == 0)
  		return false;
  
  	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 = true;
  		}
  		framesize = 0;
  #if SYNCLINK_GENERIC_HDLC
  		{
  			info->netdev->stats.rx_errors++;
  			info->netdev->stats.rx_frame_errors++;
  		}
  #endif
  	} else
  		return_frame = true;
  
  	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 true;
  }
  
  static bool 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;
  	bool 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 bool 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;
  }
  
  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(struct timer_list *t)
  {
  	MGSLPC_INFO *info = from_timer(info, t, tx_timer);
  	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 = false;
  	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
  	{
  		struct tty_struct *tty = tty_port_tty_get(&info->port);
  		bh_transmit(info, tty);
  		tty_kref_put(tty);
  	}
  }
  
  #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);
  	struct tty_struct *tty;
  	unsigned char  new_encoding;
  	unsigned short new_crctype;
  
  	/* return error if TTY interface open */
  	if (info->port.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) {
  		tty = tty_port_tty_get(&info->port);
  		mgslpc_program_hw(info, tty);
  		tty_kref_put(tty);
  	}
  
  	return 0;
  }
  
  /**
   * called by generic HDLC layer to send frame
   *
   * skb  socket buffer containing HDLC frame
   * dev  pointer to network device structure
   */
  static netdev_tx_t hdlcdev_xmit(struct sk_buff *skb,
  				      struct net_device *dev)
  {
  	MGSLPC_INFO *info = dev_to_port(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 */
  	dev->stats.tx_packets++;
  	dev->stats.tx_bytes += skb->len;
  
  	/* done with socket buffer, so free it */
  	dev_kfree_skb(skb);
  
  	/* save start time for transmit timeout detection */
  	netif_trans_update(dev);
  
  	/* start hardware transmitter if necessary */
  	spin_lock_irqsave(&info->lock, flags);
  	if (!info->tx_active) {
  		struct tty_struct *tty = tty_port_tty_get(&info->port);
  		tx_start(info, tty);
  		tty_kref_put(tty);
  	}
  	spin_unlock_irqrestore(&info->lock, flags);
  
  	return NETDEV_TX_OK;
  }
  
  /**
   * 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);
  	struct tty_struct *tty;
  	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 */
  	rc = hdlc_open(dev);
  	if (rc != 0)
  		return rc;
  
  	/* arbitrate between network and tty opens */
  	spin_lock_irqsave(&info->netlock, flags);
  	if (info->port.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);
  
  	tty = tty_port_tty_get(&info->port);
  	/* claim resources and init adapter */
  	rc = startup(info, tty);
  	if (rc != 0) {
  		tty_kref_put(tty);
  		spin_lock_irqsave(&info->netlock, flags);
  		info->netcount=0;
  		spin_unlock_irqrestore(&info->netlock, flags);
  		return rc;
  	}
  	/* assert RTS and DTR, apply hardware settings */
  	info->serial_signals |= SerialSignal_RTS | SerialSignal_DTR;
  	mgslpc_program_hw(info, tty);
  	tty_kref_put(tty);
  
  	/* enable network layer transmit */
  	netif_trans_update(dev);
  	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);
  	struct tty_struct *tty = tty_port_tty_get(&info->port);
  	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, tty);
  	tty_kref_put(tty);
  	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->port.count)
  		return -EBUSY;
  
  	if (cmd != SIOCWANDEV)
  		return hdlc_ioctl(dev, ifr, cmd);
  
  	memset(&new_line, 0, size);
  
  	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) {
  			struct tty_struct *tty = tty_port_tty_get(&info->port);
  			mgslpc_program_hw(info, tty);
  			tty_kref_put(tty);
  		}
  		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);
  	unsigned long flags;
  
  	if (debug_level >= DEBUG_LEVEL_INFO)
  		printk("hdlcdev_tx_timeout(%s)\n", dev->name);
  
  	dev->stats.tx_errors++;
  	dev->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;
  
  	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);
  		dev->stats.rx_dropped++;
  		return;
  	}
  
  	skb_put_data(skb, buf, size);
  
  	skb->protocol = hdlc_type_trans(skb, dev);
  
  	dev->stats.rx_packets++;
  	dev->stats.rx_bytes += size;
  
  	netif_rx(skb);
  }
  
  static const struct net_device_ops hdlcdev_ops = {
  	.ndo_open       = hdlcdev_open,
  	.ndo_stop       = hdlcdev_close,
  	.ndo_start_xmit = hdlc_start_xmit,
  	.ndo_do_ioctl   = hdlcdev_ioctl,
  	.ndo_tx_timeout = hdlcdev_tx_timeout,
  };
  
  /**
   * 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 */
  
  	dev = alloc_hdlcdev(info);
  	if (dev == NULL) {
  		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->netdev_ops	    = &hdlcdev_ops;
  	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 */
  	rc = register_hdlc_device(dev);
  	if (rc) {
  		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 */
  
  