drivers/tty/synclinkmp.c

/*
 * $Id: synclinkmp.c,v 4.38 2005/07/15 13:29:44 paulkf Exp $
 *
 * Device driver for Microgate SyncLink Multiport
 * high speed multiprotocol serial adapter.
 *
 * written by Paul Fulghum for Microgate Corporation
 * paulkf@microgate.com
 *
 * Microgate and SyncLink are trademarks of Microgate Corporation
 *
 * Derived from serial.c written by Theodore Ts'o and Linus Torvalds
 * 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_DEVICES 12

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/pci.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 <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/dma.h>
#include <linux/bitops.h>
#include <asm/types.h>
#include <linux/termios.h>
#include <linux/workqueue.h>
#include <linux/hdlc.h>
#include <linux/synclink.h>

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

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

#include <asm/uaccess.h>

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; */
};

/* size in bytes of DMA data buffers */
#define SCABUFSIZE 	1024
#define SCA_MEM_SIZE	0x40000
#define SCA_BASE_SIZE   512
#define SCA_REG_SIZE    16
#define SCA_MAX_PORTS   4
#define SCAMAXDESC 	128

#define	BUFFERLISTSIZE	4096

/* SCA-I style DMA buffer descriptor */
typedef struct _SCADESC
{
	u16	next;		/* lower l6 bits of next descriptor addr */
	u16	buf_ptr;	/* lower 16 bits of buffer addr */
	u8	buf_base;	/* upper 8 bits of buffer addr */
	u8	pad1;
	u16	length;		/* length of buffer */
	u8	status;		/* status of buffer */
	u8	pad2;
} SCADESC, *PSCADESC;

typedef struct _SCADESC_EX
{
	/* device driver bookkeeping section */
	char 	*virt_addr;    	/* virtual address of data buffer */
	u16	phys_entry;	/* lower 16-bits of physical address of this descriptor */
} SCADESC_EX, *PSCADESC_EX;

/* 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

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 _synclinkmp_info {
	void *if_ptr;				/* General purpose pointer (used by SPPP) */
	int			magic;
	struct tty_port		port;
	int			line;
	unsigned short		close_delay;
	unsigned short		closing_wait;	/* time to wait before closing */

	struct mgsl_icount	icount;

	int			timeout;
	int			x_char;		/* xon/xoff character */
	u16			read_status_mask1;  /* break detection (SR1 indications) */
	u16			read_status_mask2;  /* parity/framing/overun (SR2 indications) */
	unsigned char 		ignore_status_mask1;  /* break detection (SR1 indications) */
	unsigned char		ignore_status_mask2;  /* parity/framing/overun (SR2 indications) */
	unsigned char 		*tx_buf;
	int			tx_put;
	int			tx_get;
	int			tx_count;

	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 _synclinkmp_info	*next_device;	/* device list link */
	struct timer_list	status_timer;	/* input signal status check timer */

	spinlock_t lock;		/* spinlock for synchronizing with ISR */
	struct work_struct task;	 		/* task structure for scheduling bh */

	u32 max_frame_size;			/* as set by device config */

	u32 pending_bh;

	bool bh_running;				/* Protection from multiple */
	int isr_overflow;
	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;

	char *buffer_list;			/* virtual address of Rx & Tx buffer lists */
	unsigned long buffer_list_phys;

	unsigned int rx_buf_count;		/* count of total allocated Rx buffers */
	SCADESC *rx_buf_list;   		/* list of receive buffer entries */
	SCADESC_EX rx_buf_list_ex[SCAMAXDESC]; /* list of receive buffer entries */
	unsigned int current_rx_buf;

	unsigned int tx_buf_count;		/* count of total allocated Tx buffers */
	SCADESC *tx_buf_list;		/* list of transmit buffer entries */
	SCADESC_EX tx_buf_list_ex[SCAMAXDESC]; /* list of transmit buffer entries */
	unsigned int last_tx_buf;

	unsigned char *tmp_rx_buf;
	unsigned int tmp_rx_buf_count;

	bool rx_enabled;
	bool rx_overflow;

	bool tx_enabled;
	bool tx_active;
	u32 idle_mode;

	unsigned char ie0_value;
	unsigned char ie1_value;
	unsigned char ie2_value;
	unsigned char ctrlreg_value;
	unsigned char old_signals;

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

	int port_count;
	int adapter_num;
	int port_num;

	struct _synclinkmp_info *port_array[SCA_MAX_PORTS];

	unsigned int bus_type;			/* expansion bus type (ISA,EISA,PCI) */

	unsigned int irq_level;			/* interrupt level */
	unsigned long irq_flags;
	bool irq_requested;			/* true if IRQ requested */

	MGSL_PARAMS params;			/* communications parameters */

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

	bool irq_occurred;			/* for diagnostics use */
	unsigned int init_error;		/* Initialization startup error */

	u32 last_mem_alloc;
	unsigned char* memory_base;		/* shared memory address (PCI only) */
	u32 phys_memory_base;
    	int shared_mem_requested;

	unsigned char* sca_base;		/* HD64570 SCA Memory address */
	u32 phys_sca_base;
	u32 sca_offset;
	bool sca_base_requested;

	unsigned char* lcr_base;		/* local config registers (PCI only) */
	u32 phys_lcr_base;
	u32 lcr_offset;
	int lcr_mem_requested;

	unsigned char* statctrl_base;		/* status/control register memory */
	u32 phys_statctrl_base;
	u32 statctrl_offset;
	bool sca_statctrl_requested;

	u32 misc_ctrl_value;
	char flag_buf[MAX_ASYNC_BUFFER_SIZE];
	char char_buf[MAX_ASYNC_BUFFER_SIZE];
	bool drop_rts_on_tx_done;

	struct	_input_signal_events	input_signal_events;

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

#if SYNCLINK_GENERIC_HDLC
	struct net_device *netdev;
#endif

} SLMP_INFO;

#define MGSL_MAGIC 0x5401

/*
 * define serial signal status change macros
 */
#define	MISCSTATUS_DCD_LATCHED	(SerialSignal_DCD<<8)	/* indicates change in DCD */
#define MISCSTATUS_RI_LATCHED	(SerialSignal_RI<<8)	/* indicates change in RI */
#define MISCSTATUS_CTS_LATCHED	(SerialSignal_CTS<<8)	/* indicates change in CTS */
#define MISCSTATUS_DSR_LATCHED	(SerialSignal_DSR<<8)	/* change in DSR */

/* Common Register macros */
#define LPR	0x00
#define PABR0	0x02
#define PABR1	0x03
#define WCRL	0x04
#define WCRM	0x05
#define WCRH	0x06
#define DPCR	0x08
#define DMER	0x09
#define ISR0	0x10
#define ISR1	0x11
#define ISR2	0x12
#define IER0	0x14
#define IER1	0x15
#define IER2	0x16
#define ITCR	0x18
#define INTVR 	0x1a
#define IMVR	0x1c

/* MSCI Register macros */
#define TRB	0x20
#define TRBL	0x20
#define TRBH	0x21
#define SR0	0x22
#define SR1	0x23
#define SR2	0x24
#define SR3	0x25
#define FST	0x26
#define IE0	0x28
#define IE1	0x29
#define IE2	0x2a
#define FIE	0x2b
#define CMD	0x2c
#define MD0	0x2e
#define MD1	0x2f
#define MD2	0x30
#define CTL	0x31
#define SA0	0x32
#define SA1	0x33
#define IDL	0x34
#define TMC	0x35
#define RXS	0x36
#define TXS	0x37
#define TRC0	0x38
#define TRC1	0x39
#define RRC	0x3a
#define CST0	0x3c
#define CST1	0x3d

/* Timer Register Macros */
#define TCNT	0x60
#define TCNTL	0x60
#define TCNTH	0x61
#define TCONR	0x62
#define TCONRL	0x62
#define TCONRH	0x63
#define TMCS	0x64
#define TEPR	0x65

/* DMA Controller Register macros */
#define DARL	0x80
#define DARH	0x81
#define DARB	0x82
#define BAR	0x80
#define BARL	0x80
#define BARH	0x81
#define BARB	0x82
#define SAR	0x84
#define SARL	0x84
#define SARH	0x85
#define SARB	0x86
#define CPB	0x86
#define CDA	0x88
#define CDAL	0x88
#define CDAH	0x89
#define EDA	0x8a
#define EDAL	0x8a
#define EDAH	0x8b
#define BFL	0x8c
#define BFLL	0x8c
#define BFLH	0x8d
#define BCR	0x8e
#define BCRL	0x8e
#define BCRH	0x8f
#define DSR	0x90
#define DMR	0x91
#define FCT	0x93
#define DIR	0x94
#define DCMD	0x95

/* combine with timer or DMA register address */
#define TIMER0	0x00
#define TIMER1	0x08
#define TIMER2	0x10
#define TIMER3	0x18
#define RXDMA 	0x00
#define TXDMA 	0x20

/* SCA Command Codes */
#define NOOP		0x00
#define TXRESET		0x01
#define TXENABLE	0x02
#define TXDISABLE	0x03
#define TXCRCINIT	0x04
#define TXCRCEXCL	0x05
#define TXEOM		0x06
#define TXABORT		0x07
#define MPON		0x08
#define TXBUFCLR	0x09
#define RXRESET		0x11
#define RXENABLE	0x12
#define RXDISABLE	0x13
#define RXCRCINIT	0x14
#define RXREJECT	0x15
#define SEARCHMP	0x16
#define RXCRCEXCL	0x17
#define RXCRCCALC	0x18
#define CHRESET		0x21
#define HUNT		0x31

/* DMA command codes */
#define SWABORT		0x01
#define FEICLEAR	0x02

/* IE0 */
#define TXINTE 		BIT7
#define RXINTE 		BIT6
#define TXRDYE 		BIT1
#define RXRDYE 		BIT0

/* IE1 & SR1 */
#define UDRN   	BIT7
#define IDLE   	BIT6
#define SYNCD  	BIT4
#define FLGD   	BIT4
#define CCTS   	BIT3
#define CDCD   	BIT2
#define BRKD   	BIT1
#define ABTD   	BIT1
#define GAPD   	BIT1
#define BRKE   	BIT0
#define IDLD	BIT0

/* IE2 & SR2 */
#define EOM	BIT7
#define PMP	BIT6
#define SHRT	BIT6
#define PE	BIT5
#define ABT	BIT5
#define FRME	BIT4
#define RBIT	BIT4
#define OVRN	BIT3
#define CRCE	BIT2


/*
 * Global linked list of SyncLink devices
 */
static SLMP_INFO *synclinkmp_device_list = NULL;
static int synclinkmp_adapter_count = -1;
static int synclinkmp_device_count = 0;

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

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

/*
 * Array of user specified options for ISA adapters.
 */
static int debug_level = 0;
static int maxframe[MAX_DEVICES] = {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);

static char *driver_name = "SyncLink MultiPort driver";
static char *driver_version = "$Revision: 4.38 $";

static int synclinkmp_init_one(struct pci_dev *dev,const struct pci_device_id *ent);
static void synclinkmp_remove_one(struct pci_dev *dev);

static struct pci_device_id synclinkmp_pci_tbl[] = {
	{ PCI_VENDOR_ID_MICROGATE, PCI_DEVICE_ID_MICROGATE_SCA, PCI_ANY_ID, PCI_ANY_ID, },
	{ 0, }, /* terminate list */
};
MODULE_DEVICE_TABLE(pci, synclinkmp_pci_tbl);

MODULE_LICENSE("GPL");

static struct pci_driver synclinkmp_pci_driver = {
	.name		= "synclinkmp",
	.id_table	= synclinkmp_pci_tbl,
	.probe		= synclinkmp_init_one,
	.remove		= __devexit_p(synclinkmp_remove_one),
};


static struct tty_driver *serial_driver;

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


/* tty callbacks */

static int  open(struct tty_struct *tty, struct file * filp);
static void close(struct tty_struct *tty, struct file * filp);
static void hangup(struct tty_struct *tty);
static void set_termios(struct tty_struct *tty, struct ktermios *old_termios);

static int  write(struct tty_struct *tty, const unsigned char *buf, int count);
static int put_char(struct tty_struct *tty, unsigned char ch);
static void send_xchar(struct tty_struct *tty, char ch);
static void wait_until_sent(struct tty_struct *tty, int timeout);
static int  write_room(struct tty_struct *tty);
static void flush_chars(struct tty_struct *tty);
static void flush_buffer(struct tty_struct *tty);
static void tx_hold(struct tty_struct *tty);
static void tx_release(struct tty_struct *tty);

static int  ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
static int  chars_in_buffer(struct tty_struct *tty);
static void throttle(struct tty_struct * tty);
static void unthrottle(struct tty_struct * tty);
static int set_break(struct tty_struct *tty, int break_state);

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

/* ioctl handlers */

static int  get_stats(SLMP_INFO *info, struct mgsl_icount __user *user_icount);
static int  get_params(SLMP_INFO *info, MGSL_PARAMS __user *params);
static int  set_params(SLMP_INFO *info, MGSL_PARAMS __user *params);
static int  get_txidle(SLMP_INFO *info, int __user *idle_mode);
static int  set_txidle(SLMP_INFO *info, int idle_mode);
static int  tx_enable(SLMP_INFO *info, int enable);
static int  tx_abort(SLMP_INFO *info);
static int  rx_enable(SLMP_INFO *info, int enable);
static int  modem_input_wait(SLMP_INFO *info,int arg);
static int  wait_mgsl_event(SLMP_INFO *info, int __user *mask_ptr);
static int  tiocmget(struct tty_struct *tty);
static int  tiocmset(struct tty_struct *tty,
			unsigned int set, unsigned int clear);
static int  set_break(struct tty_struct *tty, int break_state);

static void add_device(SLMP_INFO *info);
static void device_init(int adapter_num, struct pci_dev *pdev);
static int  claim_resources(SLMP_INFO *info);
static void release_resources(SLMP_INFO *info);

static int  startup(SLMP_INFO *info);
static int  block_til_ready(struct tty_struct *tty, struct file * filp,SLMP_INFO *info);
static int carrier_raised(struct tty_port *port);
static void shutdown(SLMP_INFO *info);
static void program_hw(SLMP_INFO *info);
static void change_params(SLMP_INFO *info);

static bool init_adapter(SLMP_INFO *info);
static bool register_test(SLMP_INFO *info);
static bool irq_test(SLMP_INFO *info);
static bool loopback_test(SLMP_INFO *info);
static int  adapter_test(SLMP_INFO *info);
static bool memory_test(SLMP_INFO *info);

static void reset_adapter(SLMP_INFO *info);
static void reset_port(SLMP_INFO *info);
static void async_mode(SLMP_INFO *info);
static void hdlc_mode(SLMP_INFO *info);

static void rx_stop(SLMP_INFO *info);
static void rx_start(SLMP_INFO *info);
static void rx_reset_buffers(SLMP_INFO *info);
static void rx_free_frame_buffers(SLMP_INFO *info, unsigned int first, unsigned int last);
static bool rx_get_frame(SLMP_INFO *info);

static void tx_start(SLMP_INFO *info);
static void tx_stop(SLMP_INFO *info);
static void tx_load_fifo(SLMP_INFO *info);
static void tx_set_idle(SLMP_INFO *info);
static void tx_load_dma_buffer(SLMP_INFO *info, const char *buf, unsigned int count);

static void get_signals(SLMP_INFO *info);
static void set_signals(SLMP_INFO *info);
static void enable_loopback(SLMP_INFO *info, int enable);
static void set_rate(SLMP_INFO *info, u32 data_rate);

static int  bh_action(SLMP_INFO *info);
static void bh_handler(struct work_struct *work);
static void bh_receive(SLMP_INFO *info);
static void bh_transmit(SLMP_INFO *info);
static void bh_status(SLMP_INFO *info);
static void isr_timer(SLMP_INFO *info);
static void isr_rxint(SLMP_INFO *info);
static void isr_rxrdy(SLMP_INFO *info);
static void isr_txint(SLMP_INFO *info);
static void isr_txrdy(SLMP_INFO *info);
static void isr_rxdmaok(SLMP_INFO *info);
static void isr_rxdmaerror(SLMP_INFO *info);
static void isr_txdmaok(SLMP_INFO *info);
static void isr_txdmaerror(SLMP_INFO *info);
static void isr_io_pin(SLMP_INFO *info, u16 status);

static int  alloc_dma_bufs(SLMP_INFO *info);
static void free_dma_bufs(SLMP_INFO *info);
static int  alloc_buf_list(SLMP_INFO *info);
static int  alloc_frame_bufs(SLMP_INFO *info, SCADESC *list, SCADESC_EX *list_ex,int count);
static int  alloc_tmp_rx_buf(SLMP_INFO *info);
static void free_tmp_rx_buf(SLMP_INFO *info);

static void load_pci_memory(SLMP_INFO *info, char* dest, const char* src, unsigned short count);
static void trace_block(SLMP_INFO *info, const char* data, int count, int xmit);
static void tx_timeout(unsigned long context);
static void status_timeout(unsigned long context);

static unsigned char read_reg(SLMP_INFO *info, unsigned char addr);
static void write_reg(SLMP_INFO *info, unsigned char addr, unsigned char val);
static u16 read_reg16(SLMP_INFO *info, unsigned char addr);
static void write_reg16(SLMP_INFO *info, unsigned char addr, u16 val);
static unsigned char read_status_reg(SLMP_INFO * info);
static void write_control_reg(SLMP_INFO * info);


static unsigned char rx_active_fifo_level = 16;	// rx request FIFO activation level in bytes
static unsigned char tx_active_fifo_level = 16;	// tx request FIFO activation level in bytes
static unsigned char tx_negate_fifo_level = 32;	// tx request FIFO negation level in bytes

static u32 misc_ctrl_value = 0x007e4040;
static u32 lcr1_brdr_value = 0x00800028;

static u32 read_ahead_count = 8;

/* DPCR, DMA Priority Control
 *
 * 07..05  Not used, must be 0
 * 04      BRC, bus release condition: 0=all transfers complete
 *              1=release after 1 xfer on all channels
 * 03      CCC, channel change condition: 0=every cycle
 *              1=after each channel completes all xfers
 * 02..00  PR<2..0>, priority 100=round robin
 *
 * 00000100 = 0x00
 */
static unsigned char dma_priority = 0x04;

// Number of bytes that can be written to shared RAM
// in a single write operation
static u32 sca_pci_load_interval = 64;

/*
 * 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* synclinkmp_get_text_ptr(void);
static void* synclinkmp_get_text_ptr(void) {return synclinkmp_get_text_ptr;}

static inline int sanity_check(SLMP_INFO *info,
			       char *name, const char *routine)
{
#ifdef SANITY_CHECK
	static const char *badmagic =
		"Warning: bad magic number for synclinkmp_struct (%s) in %s\n";
	static const char *badinfo =
		"Warning: null synclinkmp_struct for (%s) in %s\n";

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

/**
 * 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);
	}
}

/* tty callbacks */

/* Called when a port is opened.  Init and enable port.
 */
static int open(struct tty_struct *tty, struct file *filp)
{
	SLMP_INFO *info;
	int retval, line;
	unsigned long flags;

	line = tty->index;
	if ((line < 0) || (line >= synclinkmp_device_count)) {
		printk("%s(%d): open with invalid line #%d.\n",
			__FILE__,__LINE__,line);
		return -ENODEV;
	}

	info = synclinkmp_device_list;
	while(info && info->line != line)
		info = info->next_device;
	if (sanity_check(info, tty->name, "open"))
		return -ENODEV;
	if ( info->init_error ) {
		printk("%s(%d):%s device is not allocated, init error=%d\n",
			__FILE__,__LINE__,info->device_name,info->init_error);
		return -ENODEV;
	}

	tty->driver_data = info;
	info->port.tty = tty;

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

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

	info->port.tty->low_latency = (info->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;
	}
	info->port.count++;
	spin_unlock_irqrestore(&info->netlock, flags);

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

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

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

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

	return retval;
}

/* Called when port is closed. Wait for remaining data to be
 * sent. Disable port and free resources.
 */
static void close(struct tty_struct *tty, struct file *filp)
{
	SLMP_INFO * info = tty->driver_data;

	if (sanity_check(info, tty->name, "close"))
		return;

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

	if (tty_port_close_start(&info->port, tty, filp) == 0)
		goto cleanup;

	mutex_lock(&info->port.mutex);
 	if (info->port.flags & ASYNC_INITIALIZED)
 		wait_until_sent(tty, info->timeout);

	flush_buffer(tty);
	tty_ldisc_flush(tty);
	shutdown(info);
	mutex_unlock(&info->port.mutex);

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

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

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

	if (sanity_check(info, tty->name, "hangup"))
		return;

	mutex_lock(&info->port.mutex);
	flush_buffer(tty);
	shutdown(info);

	spin_lock_irqsave(&info->port.lock, flags);
	info->port.count = 0;
	info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
	info->port.tty = NULL;
	spin_unlock_irqrestore(&info->port.lock, flags);
	mutex_unlock(&info->port.mutex);

	wake_up_interruptible(&info->port.open_wait);
}

/* Set new termios settings
 */
static void set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
	SLMP_INFO *info = tty->driver_data;
	unsigned long flags;

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

	change_params(info);

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

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

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

/* 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
 *
 * Return Value:	number of characters written
 */
static int write(struct tty_struct *tty,
		 const unsigned char *buf, int count)
{
	int	c, ret = 0;
	SLMP_INFO *info = tty->driver_data;
	unsigned long flags;

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

	if (sanity_check(info, tty->name, "write"))
		goto cleanup;

	if (!info->tx_buf)
		goto cleanup;

	if (info->params.mode == MGSL_MODE_HDLC) {
		if (count > info->max_frame_size) {
			ret = -EIO;
			goto cleanup;
		}
		if (info->tx_active)
			goto cleanup;
		if (info->tx_count) {
			/* send accumulated data from send_char() calls */
			/* as frame and wait before accepting more data. */
			tx_load_dma_buffer(info, info->tx_buf, info->tx_count);
			goto start;
		}
		ret = info->tx_count = count;
		tx_load_dma_buffer(info, buf, count);
		goto start;
	}

	for (;;) {
		c = min_t(int, count,
			min(info->max_frame_size - info->tx_count - 1,
			    info->max_frame_size - 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 += c;
		if (info->tx_put >= info->max_frame_size)
			info->tx_put -= info->max_frame_size;
		info->tx_count += c;
		spin_unlock_irqrestore(&info->lock,flags);

		buf += c;
		count -= c;
		ret += c;
	}

	if (info->params.mode == MGSL_MODE_HDLC) {
		if (count) {
			ret = info->tx_count = 0;
			goto cleanup;
		}
		tx_load_dma_buffer(info, info->tx_buf, info->tx_count);
	}
start:
 	if (info->tx_count && !tty->stopped && !tty->hw_stopped) {
		spin_lock_irqsave(&info->lock,flags);
		if (!info->tx_active)
		 	tx_start(info);
		spin_unlock_irqrestore(&info->lock,flags);
 	}

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

/* Add a character to the transmit buffer.
 */
static int put_char(struct tty_struct *tty, unsigned char ch)
{
	SLMP_INFO *info = tty->driver_data;
	unsigned long flags;
	int ret = 0;

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

	if (sanity_check(info, tty->name, "put_char"))
		return 0;

	if (!info->tx_buf)
		return 0;

	spin_lock_irqsave(&info->lock,flags);

	if ( (info->params.mode != MGSL_MODE_HDLC) ||
	     !info->tx_active ) {

		if (info->tx_count < info->max_frame_size - 1) {
			info->tx_buf[info->tx_put++] = ch;
			if (info->tx_put >= info->max_frame_size)
				info->tx_put -= info->max_frame_size;
			info->tx_count++;
			ret = 1;
		}
	}

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

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

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

	if (sanity_check(info, tty->name, "send_xchar"))
		return;

	info->x_char = ch;
	if (ch) {
		/* Make sure transmit interrupts are on */
		spin_lock_irqsave(&info->lock,flags);
		if (!info->tx_enabled)
		 	tx_start(info);
		spin_unlock_irqrestore(&info->lock,flags);
	}
}

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

	if (!info )
		return;

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

	if (sanity_check(info, tty->name, "wait_until_sent"))
		return;

	if (!test_bit(ASYNCB_INITIALIZED, &info->port.flags))
		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 {
		/*
		 * TODO: determine if there is something similar to USC16C32
		 * 	 TXSTATUS_ALL_SENT status
		 */
		while ( 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):%s wait_until_sent() exit\n",
			 __FILE__,__LINE__, info->device_name );
}

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

	if (sanity_check(info, tty->name, "write_room"))
		return 0;

	if (info->params.mode == MGSL_MODE_HDLC) {
		ret = (info->tx_active) ? 0 : HDLC_MAX_FRAME_SIZE;
	} else {
		ret = info->max_frame_size - info->tx_count - 1;
		if (ret < 0)
			ret = 0;
	}

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

	return ret;
}

/* enable transmitter and send remaining buffered characters
 */
static void flush_chars(struct tty_struct *tty)
{
	SLMP_INFO *info = tty->driver_data;
	unsigned long flags;

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

	if (sanity_check(info, tty->name, "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):%s flush_chars() entry, starting transmitter\n",
			__FILE__,__LINE__,info->device_name );

	spin_lock_irqsave(&info->lock,flags);

	if (!info->tx_active) {
		if ( (info->params.mode == MGSL_MODE_HDLC) &&
			info->tx_count ) {
			/* operating in synchronous (frame oriented) mode */
			/* copy data from circular tx_buf to */
			/* transmit DMA buffer. */
			tx_load_dma_buffer(info,
				 info->tx_buf,info->tx_count);
		}
	 	tx_start(info);
	}

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

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

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

	if (sanity_check(info, tty->name, "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);

	tty_wakeup(tty);
}

/* throttle (stop) transmitter
 */
static void tx_hold(struct tty_struct *tty)
{
	SLMP_INFO *info = tty->driver_data;
	unsigned long flags;

	if (sanity_check(info, tty->name, "tx_hold"))
		return;

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

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

/* release (start) transmitter
 */
static void tx_release(struct tty_struct *tty)
{
	SLMP_INFO *info = tty->driver_data;
	unsigned long flags;

	if (sanity_check(info, tty->name, "tx_release"))
		return;

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

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

/* 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 ioctl(struct tty_struct *tty,
		 unsigned int cmd, unsigned long arg)
{
	SLMP_INFO *info = tty->driver_data;
	void __user *argp = (void __user *)arg;

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

	if (sanity_check(info, tty->name, "ioctl"))
		return -ENODEV;

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

	switch (cmd) {
	case MGSL_IOCGPARAMS:
		return get_params(info, argp);
	case MGSL_IOCSPARAMS:
		return set_params(info, argp);
	case MGSL_IOCGTXIDLE:
		return get_txidle(info, argp);
	case MGSL_IOCSTXIDLE:
		return set_txidle(info, (int)arg);
	case MGSL_IOCTXENABLE:
		return tx_enable(info, (int)arg);
	case MGSL_IOCRXENABLE:
		return rx_enable(info, (int)arg);
	case MGSL_IOCTXABORT:
		return tx_abort(info);
	case MGSL_IOCGSTATS:
		return get_stats(info, argp);
	case MGSL_IOCWAITEVENT:
		return wait_mgsl_event(info, argp);
	case MGSL_IOCLOOPTXDONE:
		return 0; // TODO: Not supported, need to document
		/* Wait for modem input (DCD,RI,DSR,CTS) change
		 * as specified by mask in arg (TIOCM_RNG/DSR/CD/CTS)
		 */
	case TIOCMIWAIT:
		return modem_input_wait(info,(int)arg);
		
		/*
		 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
		 * Return: write counters to the user passed counter struct
		 * NB: both 1->0 and 0->1 transitions are counted except for
		 *     RI where only 0->1 is counted.
		 */
	default:
		return -ENOIOCTLCMD;
	}
	return 0;
}

static int get_icount(struct tty_struct *tty,
				struct serial_icounter_struct *icount)
{
	SLMP_INFO *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;
}

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

static inline void line_info(struct seq_file *m, SLMP_INFO *info)
{
	char	stat_buf[30];
	unsigned long flags;

	seq_printf(m, "%s: SCABase=%08x Mem=%08X StatusControl=%08x LCR=%08X\n"
		       "\tIRQ=%d MaxFrameSize=%u\n",
		info->device_name,
		info->phys_sca_base,
		info->phys_memory_base,
		info->phys_statctrl_base,
		info->phys_lcr_base,
		info->irq_level,
		info->max_frame_size );

	/* 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, "\tHDLC 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, " rxlong:%d", info->icount.rxcrc);
	} else {
		seq_printf(m, "\tASYNC 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, "\ttxactive=%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 synclinkmp_proc_show(struct seq_file *m, void *v)
{
	SLMP_INFO *info;

	seq_printf(m, "synclinkmp driver:%s\n", driver_version);

	info = synclinkmp_device_list;
	while( info ) {
		line_info(m, info);
		info = info->next_device;
	}
	return 0;
}

static int synclinkmp_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, synclinkmp_proc_show, NULL);
}

static const struct file_operations synclinkmp_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= synclinkmp_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

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

	if (sanity_check(info, tty->name, "chars_in_buffer"))
		return 0;

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

	return info->tx_count;
}

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

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

	if (sanity_check(info, tty->name, "throttle"))
		return;

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

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

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

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

	if (sanity_check(info, tty->name, "unthrottle"))
		return;

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

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

/* set or clear transmit break condition
 * break_state	-1=set break condition, 0=clear
 */
static int set_break(struct tty_struct *tty, int break_state)
{
	unsigned char RegValue;
	SLMP_INFO * info = tty->driver_data;
	unsigned long flags;

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

	if (sanity_check(info, tty->name, "set_break"))
		return -EINVAL;

	spin_lock_irqsave(&info->lock,flags);
	RegValue = read_reg(info, CTL);
 	if (break_state == -1)
		RegValue |= BIT3;
	else
		RegValue &= ~BIT3;
	write_reg(info, CTL, RegValue);
	spin_unlock_irqrestore(&info->lock,flags);
	return 0;
}

#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)
{
	SLMP_INFO *info = dev_to_port(dev);
	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)
		program_hw(info);

	return 0;
}

/**
 * called by generic HDLC layer to send frame
 *
 * skb  socket buffer containing HDLC frame
 * dev  pointer to network device structure
 */
static netdev_tx_t hdlcdev_xmit(struct sk_buff *skb,
				      struct net_device *dev)
{
	SLMP_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 */
	info->tx_count = skb->len;
	tx_load_dma_buffer(info, skb->data, 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 */
	dev->trans_start = jiffies;

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

	return 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)
{
	SLMP_INFO *info = dev_to_port(dev);
	int rc;
	unsigned long flags;

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

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

	/* arbitrate between network and tty opens */
	spin_lock_irqsave(&info->netlock, flags);
	if (info->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);

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

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

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

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

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

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

	netif_stop_queue(dev);

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

	hdlc_close(dev);

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

	return 0;
}

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

	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)
			program_hw(info);
		return 0;

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

/**
 * called by network layer when transmit timeout is detected
 *
 * dev  pointer to network device structure
 */
static void hdlcdev_tx_timeout(struct net_device *dev)
{
	SLMP_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(SLMP_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(SLMP_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;
	}

	memcpy(skb_put(skb, size), 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_change_mtu = hdlc_change_mtu,
	.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(SLMP_INFO *info)
{
	int rc;
	struct net_device *dev;
	hdlc_device *hdlc;

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

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

	/* for network layer reporting purposes only */
	dev->mem_start = info->phys_sca_base;
	dev->mem_end   = info->phys_sca_base + SCA_BASE_SIZE - 1;
	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 */
	if ((rc = register_hdlc_device(dev))) {
		printk(KERN_WARNING "%s:unable to register hdlc device\n",__FILE__);
		free_netdev(dev);
		return rc;
	}

	info->netdev = dev;
	return 0;
}

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

#endif /* CONFIG_HDLC */


/* Return next bottom half action to perform.
 * Return Value:	BH action code or 0 if nothing to do.
 */
static int bh_action(SLMP_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;
}

/* Perform bottom half processing of work items queued by ISR.
 */
static void bh_handler(struct work_struct *work)
{
	SLMP_INFO *info = container_of(work, SLMP_INFO, task);
	int action;

	if (!info)
		return;

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

	info->bh_running = true;

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

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

		switch (action) {

		case BH_RECEIVE:
			bh_receive(info);
			break;
		case BH_TRANSMIT:
			bh_transmit(info);
			break;
		case BH_STATUS:
			bh_status(info);
			break;
		default:
			/* unknown work item ID */
			printk("%s(%d):%s Unknown work item ID=%08X!\n",
				__FILE__,__LINE__,info->device_name,action);
			break;
		}
	}

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

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

	while( rx_get_frame(info) );
}

static void bh_transmit(SLMP_INFO *info)
{
	struct tty_struct *tty = info->port.tty;

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

	if (tty)
		tty_wakeup(tty);
}

static void bh_status(SLMP_INFO *info)
{
	if ( debug_level >= DEBUG_LEVEL_BH )
		printk( "%s(%d):%s bh_status() entry\n",
			__FILE__,__LINE__,info->device_name);

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

static void isr_timer(SLMP_INFO * info)
{
	unsigned char timer = (info->port_num & 1) ? TIMER2 : TIMER0;

	/* IER2<7..4> = timer<3..0> interrupt enables (0=disabled) */
	write_reg(info, IER2, 0);

	/* TMCS, Timer Control/Status Register
	 *
	 * 07      CMF, Compare match flag (read only) 1=match
	 * 06      ECMI, CMF Interrupt Enable: 0=disabled
	 * 05      Reserved, must be 0
	 * 04      TME, Timer Enable
	 * 03..00  Reserved, must be 0
	 *
	 * 0000 0000
	 */
	write_reg(info, (unsigned char)(timer + TMCS), 0);

	info->irq_occurred = true;

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

static void isr_rxint(SLMP_INFO * info)
{
 	struct tty_struct *tty = info->port.tty;
 	struct	mgsl_icount *icount = &info->icount;
	unsigned char status = read_reg(info, SR1) & info->ie1_value & (FLGD + IDLD + CDCD + BRKD);
	unsigned char status2 = read_reg(info, SR2) & info->ie2_value & OVRN;

	/* clear status bits */
	if (status)
		write_reg(info, SR1, status);

	if (status2)
		write_reg(info, SR2, status2);
	
	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):%s isr_rxint status=%02X %02x\n",
			__FILE__,__LINE__,info->device_name,status,status2);

	if (info->params.mode == MGSL_MODE_ASYNC) {
		if (status & BRKD) {
			icount->brk++;

			/* process break detection if tty control
			 * is not set to ignore it
			 */
			if ( tty ) {
				if (!(status & info->ignore_status_mask1)) {
					if (info->read_status_mask1 & BRKD) {
						tty_insert_flip_char(tty, 0, TTY_BREAK);
						if (info->port.flags & ASYNC_SAK)
							do_SAK(tty);
					}
				}
			}
		}
	}
	else {
		if (status & (FLGD|IDLD)) {
			if (status & FLGD)
				info->icount.exithunt++;
			else if (status & IDLD)
				info->icount.rxidle++;
			wake_up_interruptible(&info->event_wait_q);
		}
	}

	if (status & CDCD) {
		/* simulate a common modem status change interrupt
		 * for our handler
		 */
		get_signals( info );
		isr_io_pin(info,
			MISCSTATUS_DCD_LATCHED|(info->serial_signals&SerialSignal_DCD));
	}
}

/*
 * handle async rx data interrupts
 */
static void isr_rxrdy(SLMP_INFO * info)
{
	u16 status;
	unsigned char DataByte;
 	struct tty_struct *tty = info->port.tty;
 	struct	mgsl_icount *icount = &info->icount;

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

	while((status = read_reg(info,CST0)) & BIT0)
	{
		int flag = 0;
		bool over = false;
		DataByte = read_reg(info,TRB);

		icount->rx++;

		if ( status & (PE + FRME + OVRN) ) {
			printk("%s(%d):%s rxerr=%04X\n",
				__FILE__,__LINE__,info->device_name,status);

			/* update error statistics */
			if (status & PE)
				icount->parity++;
			else if (status & FRME)
				icount->frame++;
			else if (status & OVRN)
				icount->overrun++;

			/* discard char if tty control flags say so */
			if (status & info->ignore_status_mask2)
				continue;

			status &= info->read_status_mask2;

			if ( tty ) {
				if (status & PE)
					flag = TTY_PARITY;
				else if (status & FRME)
					flag = TTY_FRAME;
				if (status & OVRN) {
					/* Overrun is special, since it's
					 * reported immediately, and doesn't
					 * affect the current character
					 */
					over = true;
				}
			}
		}	/* end of if (error) */

		if ( tty ) {
			tty_insert_flip_char(tty, DataByte, flag);
			if (over)
				tty_insert_flip_char(tty, 0, TTY_OVERRUN);
		}
	}

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

	if ( tty )
		tty_flip_buffer_push(tty);
}

static void isr_txeom(SLMP_INFO * info, unsigned char status)
{
	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):%s isr_txeom status=%02x\n",
			__FILE__,__LINE__,info->device_name,status);

	write_reg(info, TXDMA + DIR, 0x00); /* disable Tx DMA IRQs */
	write_reg(info, TXDMA + DSR, 0xc0); /* clear IRQs and disable DMA */
	write_reg(info, TXDMA + DCMD, SWABORT);	/* reset/init DMA channel */

	if (status & UDRN) {
		write_reg(info, CMD, TXRESET);
		write_reg(info, CMD, TXENABLE);
	} else
		write_reg(info, CMD, TXBUFCLR);

	/* disable and clear tx interrupts */
	info->ie0_value &= ~TXRDYE;
	info->ie1_value &= ~(IDLE + UDRN);
	write_reg16(info, IE0, (unsigned short)((info->ie1_value << 8) + info->ie0_value));
	write_reg(info, SR1, (unsigned char)(UDRN + IDLE));

	if ( info->tx_active ) {
		if (info->params.mode != MGSL_MODE_ASYNC) {
			if (status & UDRN)
				info->icount.txunder++;
			else if (status & IDLE)
				info->icount.txok++;
		}

		info->tx_active = false;
		info->tx_count = info->tx_put = info->tx_get = 0;

		del_timer(&info->tx_timer);

		if (info->params.mode != MGSL_MODE_ASYNC && info->drop_rts_on_tx_done ) {
			info->serial_signals &= ~SerialSignal_RTS;
			info->drop_rts_on_tx_done = false;
			set_signals(info);
		}

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


/*
 * handle tx status interrupts
 */
static void isr_txint(SLMP_INFO * info)
{
	unsigned char status = read_reg(info, SR1) & info->ie1_value & (UDRN + IDLE + CCTS);

	/* clear status bits */
	write_reg(info, SR1, status);

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):%s isr_txint status=%02x\n",
			__FILE__,__LINE__,info->device_name,status);

	if (status & (UDRN + IDLE))
		isr_txeom(info, status);

	if (status & CCTS) {
		/* simulate a common modem status change interrupt
		 * for our handler
		 */
		get_signals( info );
		isr_io_pin(info,
			MISCSTATUS_CTS_LATCHED|(info->serial_signals&SerialSignal_CTS));

	}
}

/*
 * handle async tx data interrupts
 */
static void isr_txrdy(SLMP_INFO * info)
{
	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):%s isr_txrdy() tx_count=%d\n",
			__FILE__,__LINE__,info->device_name,info->tx_count);

	if (info->params.mode != MGSL_MODE_ASYNC) {
		/* disable TXRDY IRQ, enable IDLE IRQ */
		info->ie0_value &= ~TXRDYE;
		info->ie1_value |= IDLE;
		write_reg16(info, IE0, (unsigned short)((info->ie1_value << 8) + info->ie0_value));
		return;
	}

	if (info->port.tty && (info->port.tty->stopped || info->port.tty->hw_stopped)) {
		tx_stop(info);
		return;
	}

	if ( info->tx_count )
		tx_load_fifo( info );
	else {
		info->tx_active = false;
		info->ie0_value &= ~TXRDYE;
		write_reg(info, IE0, info->ie0_value);
	}

	if (info->tx_count < WAKEUP_CHARS)
		info->pending_bh |= BH_TRANSMIT;
}

static void isr_rxdmaok(SLMP_INFO * info)
{
	/* BIT7 = EOT (end of transfer)
	 * BIT6 = EOM (end of message/frame)
	 */
	unsigned char status = read_reg(info,RXDMA + DSR) & 0xc0;

	/* clear IRQ (BIT0 must be 1 to prevent clearing DE bit) */
	write_reg(info, RXDMA + DSR, (unsigned char)(status | 1));

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):%s isr_rxdmaok(), status=%02x\n",
			__FILE__,__LINE__,info->device_name,status);

	info->pending_bh |= BH_RECEIVE;
}

static void isr_rxdmaerror(SLMP_INFO * info)
{
	/* BIT5 = BOF (buffer overflow)
	 * BIT4 = COF (counter overflow)
	 */
	unsigned char status = read_reg(info,RXDMA + DSR) & 0x30;

	/* clear IRQ (BIT0 must be 1 to prevent clearing DE bit) */
	write_reg(info, RXDMA + DSR, (unsigned char)(status | 1));

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):%s isr_rxdmaerror(), status=%02x\n",
			__FILE__,__LINE__,info->device_name,status);

	info->rx_overflow = true;
	info->pending_bh |= BH_RECEIVE;
}

static void isr_txdmaok(SLMP_INFO * info)
{
	unsigned char status_reg1 = read_reg(info, SR1);

	write_reg(info, TXDMA + DIR, 0x00);	/* disable Tx DMA IRQs */
	write_reg(info, TXDMA + DSR, 0xc0); /* clear IRQs and disable DMA */
	write_reg(info, TXDMA + DCMD, SWABORT);	/* reset/init DMA channel */

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):%s isr_txdmaok(), status=%02x\n",
			__FILE__,__LINE__,info->device_name,status_reg1);

	/* program TXRDY as FIFO empty flag, enable TXRDY IRQ */
	write_reg16(info, TRC0, 0);
	info->ie0_value |= TXRDYE;
	write_reg(info, IE0, info->ie0_value);
}

static void isr_txdmaerror(SLMP_INFO * info)
{
	/* BIT5 = BOF (buffer overflow)
	 * BIT4 = COF (counter overflow)
	 */
	unsigned char status = read_reg(info,TXDMA + DSR) & 0x30;

	/* clear IRQ (BIT0 must be 1 to prevent clearing DE bit) */
	write_reg(info, TXDMA + DSR, (unsigned char)(status | 1));

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):%s isr_txdmaerror(), status=%02x\n",
			__FILE__,__LINE__,info->device_name,status);
}

/* handle input serial signal changes
 */
static void isr_io_pin( SLMP_INFO *info, u16 status )
{
 	struct	mgsl_icount *icount;

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):isr_io_pin status=%04X\n",
			__FILE__,__LINE__,status);

	if (status & (MISCSTATUS_CTS_LATCHED | MISCSTATUS_DCD_LATCHED |
	              MISCSTATUS_DSR_LATCHED | MISCSTATUS_RI_LATCHED) ) {
		icount = &info->icount;
		/* update input line counters */
		if (status & MISCSTATUS_RI_LATCHED) {
			icount->rng++;
			if ( status & SerialSignal_RI )
				info->input_signal_events.ri_up++;
			else
				info->input_signal_events.ri_down++;
		}
		if (status & MISCSTATUS_DSR_LATCHED) {
			icount->dsr++;
			if ( status & SerialSignal_DSR )
				info->input_signal_events.dsr_up++;
			else
				info->input_signal_events.dsr_down++;
		}
		if (status & MISCSTATUS_DCD_LATCHED) {
			if ((info->dcd_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT) {
				info->ie1_value &= ~CDCD;
				write_reg(info, IE1, info->ie1_value);
			}
			icount->dcd++;
			if (status & SerialSignal_DCD) {
				info->input_signal_events.dcd_up++;
			} else
				info->input_signal_events.dcd_down++;
#if SYNCLINK_GENERIC_HDLC
			if (info->netcount) {
				if (status & SerialSignal_DCD)
					netif_carrier_on(info->netdev);
				else
					netif_carrier_off(info->netdev);
			}
#endif
		}
		if (status & MISCSTATUS_CTS_LATCHED)
		{
			if ((info->cts_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT) {
				info->ie1_value &= ~CCTS;
				write_reg(info, IE1, info->ie1_value);
			}
			icount->cts++;
			if ( status & SerialSignal_CTS )
				info->input_signal_events.cts_up++;
			else
				info->input_signal_events.cts_down++;
		}
		wake_up_interruptible(&info->status_event_wait_q);
		wake_up_interruptible(&info->event_wait_q);

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

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

	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
 * 	regs		interrupted processor context
 */
static irqreturn_t synclinkmp_interrupt(int dummy, void *dev_id)
{
	SLMP_INFO *info = dev_id;
	unsigned char status, status0, status1=0;
	unsigned char dmastatus, dmastatus0, dmastatus1=0;
	unsigned char timerstatus0, timerstatus1=0;
	unsigned char shift;
	unsigned int i;
	unsigned short tmp;

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk(KERN_DEBUG "%s(%d): synclinkmp_interrupt(%d)entry.\n",
			__FILE__, __LINE__, info->irq_level);

	spin_lock(&info->lock);

	for(;;) {

		/* get status for SCA0 (ports 0-1) */
		tmp = read_reg16(info, ISR0);	/* get ISR0 and ISR1 in one read */
		status0 = (unsigned char)tmp;
		dmastatus0 = (unsigned char)(tmp>>8);
		timerstatus0 = read_reg(info, ISR2);

		if ( debug_level >= DEBUG_LEVEL_ISR )
			printk(KERN_DEBUG "%s(%d):%s status0=%02x, dmastatus0=%02x, timerstatus0=%02x\n",
				__FILE__, __LINE__, info->device_name,
				status0, dmastatus0, timerstatus0);

		if (info->port_count == 4) {
			/* get status for SCA1 (ports 2-3) */
			tmp = read_reg16(info->port_array[2], ISR0);
			status1 = (unsigned char)tmp;
			dmastatus1 = (unsigned char)(tmp>>8);
			timerstatus1 = read_reg(info->port_array[2], ISR2);

			if ( debug_level >= DEBUG_LEVEL_ISR )
				printk("%s(%d):%s status1=%02x, dmastatus1=%02x, timerstatus1=%02x\n",
					__FILE__,__LINE__,info->device_name,
					status1,dmastatus1,timerstatus1);
		}

		if (!status0 && !dmastatus0 && !timerstatus0 &&
			 !status1 && !dmastatus1 && !timerstatus1)
			break;

		for(i=0; i < info->port_count ; i++) {
			if (info->port_array[i] == NULL)
				continue;
			if (i < 2) {
				status = status0;
				dmastatus = dmastatus0;
			} else {
				status = status1;
				dmastatus = dmastatus1;
			}

			shift = i & 1 ? 4 :0;

			if (status & BIT0 << shift)
				isr_rxrdy(info->port_array[i]);
			if (status & BIT1 << shift)
				isr_txrdy(info->port_array[i]);
			if (status & BIT2 << shift)
				isr_rxint(info->port_array[i]);
			if (status & BIT3 << shift)
				isr_txint(info->port_array[i]);

			if (dmastatus & BIT0 << shift)
				isr_rxdmaerror(info->port_array[i]);
			if (dmastatus & BIT1 << shift)
				isr_rxdmaok(info->port_array[i]);
			if (dmastatus & BIT2 << shift)
				isr_txdmaerror(info->port_array[i]);
			if (dmastatus & BIT3 << shift)
				isr_txdmaok(info->port_array[i]);
		}

		if (timerstatus0 & (BIT5 | BIT4))
			isr_timer(info->port_array[0]);
		if (timerstatus0 & (BIT7 | BIT6))
			isr_timer(info->port_array[1]);
		if (timerstatus1 & (BIT5 | BIT4))
			isr_timer(info->port_array[2]);
		if (timerstatus1 & (BIT7 | BIT6))
			isr_timer(info->port_array[3]);
	}

	for(i=0; i < info->port_count ; i++) {
		SLMP_INFO * port = info->port_array[i];

		/* Request bottom half processing if there's something
		 * for it to do and the bh is not already running.
		 *
		 * Note: startup adapter diags require interrupts.
		 * do not request bottom half processing if the
		 * device is not open in a normal mode.
		 */
		if ( port && (port->port.count || port->netcount) &&
		     port->pending_bh && !port->bh_running &&
		     !port->bh_requested ) {
			if ( debug_level >= DEBUG_LEVEL_ISR )
				printk("%s(%d):%s queueing bh task.\n",
					__FILE__,__LINE__,port->device_name);
			schedule_work(&port->task);
			port->bh_requested = true;
		}
	}

	spin_unlock(&info->lock);

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk(KERN_DEBUG "%s(%d):synclinkmp_interrupt(%d)exit.\n",
			__FILE__, __LINE__, info->irq_level);
	return IRQ_HANDLED;
}

/* Initialize and start device.
 */
static int startup(SLMP_INFO * info)
{
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk("%s(%d):%s tx_releaseup()\n",__FILE__,__LINE__,info->device_name);

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

	if (!info->tx_buf) {
		info->tx_buf = kmalloc(info->max_frame_size, 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));

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

	change_params(info);

	mod_timer(&info->status_timer, jiffies + msecs_to_jiffies(10));

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

	info->port.flags |= ASYNC_INITIALIZED;

	return 0;
}

/* Called by close() and hangup() to shutdown hardware
 */
static void shutdown(SLMP_INFO * info)
{
	unsigned long flags;

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

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):%s synclinkmp_shutdown()\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(&info->tx_timer);
	del_timer(&info->status_timer);

	kfree(info->tx_buf);
	info->tx_buf = NULL;

	spin_lock_irqsave(&info->lock,flags);

	reset_port(info);

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

	spin_unlock_irqrestore(&info->lock,flags);

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

	info->port.flags &= ~ASYNC_INITIALIZED;
}

static void program_hw(SLMP_INFO *info)
{
	unsigned long flags;

	spin_lock_irqsave(&info->lock,flags);

	rx_stop(info);
	tx_stop(info);

	info->tx_count = info->tx_put = info->tx_get = 0;

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

	set_signals(info);

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

	info->ie1_value |= (CDCD|CCTS);
	write_reg(info, IE1, info->ie1_value);

	get_signals(info);

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

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

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

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

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

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

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

	/* byte size and parity */

	switch (cflag & CSIZE) {
	      case CS5: info->params.data_bits = 5; break;
	      case CS6: info->params.data_bits = 6; break;
	      case CS7: info->params.data_bits = 7; break;
	      case CS8: info->params.data_bits = 8; break;
	      /* Never happens, but GCC is too dumb to figure it out */
	      default:  info->params.data_bits = 7; break;
	      }

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

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

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

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

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

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

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

	/* process tty input control flags */

	info->read_status_mask2 = OVRN;
	if (I_INPCK(info->port.tty))
		info->read_status_mask2 |= PE | FRME;
 	if (I_BRKINT(info->port.tty) || I_PARMRK(info->port.tty))
 		info->read_status_mask1 |= BRKD;
	if (I_IGNPAR(info->port.tty))
		info->ignore_status_mask2 |= PE | FRME;
	if (I_IGNBRK(info->port.tty)) {
		info->ignore_status_mask1 |= BRKD;
		/* If ignoring parity and break indicators, ignore
		 * overruns too.  (For real raw support).
		 */
		if (I_IGNPAR(info->port.tty))
			info->ignore_status_mask2 |= OVRN;
	}

	program_hw(info);
}

static int get_stats(SLMP_INFO * info, struct mgsl_icount __user *user_icount)
{
	int err;

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

	if (!user_icount) {
		memset(&info->icount, 0, sizeof(info->icount));
	} else {
		mutex_lock(&info->port.mutex);
		COPY_TO_USER(err, user_icount, &info->icount, sizeof(struct mgsl_icount));
		mutex_unlock(&info->port.mutex);
		if (err)
			return -EFAULT;
	}

	return 0;
}

static int get_params(SLMP_INFO * info, MGSL_PARAMS __user *user_params)
{
	int err;
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):%s get_params()\n",
			 __FILE__,__LINE__, info->device_name);

	mutex_lock(&info->port.mutex);
	COPY_TO_USER(err,user_params, &info->params, sizeof(MGSL_PARAMS));
	mutex_unlock(&info->port.mutex);
	if (err) {
		if ( debug_level >= DEBUG_LEVEL_INFO )
			printk( "%s(%d):%s get_params() user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}

	return 0;
}

static int set_params(SLMP_INFO * info, MGSL_PARAMS __user *new_params)
{
 	unsigned long flags;
	MGSL_PARAMS tmp_params;
	int err;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):%s set_params\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):%s set_params() user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}

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

 	change_params(info);
	mutex_unlock(&info->port.mutex);

	return 0;
}

static int get_txidle(SLMP_INFO * info, int __user *idle_mode)
{
	int err;

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

	COPY_TO_USER(err,idle_mode, &info->idle_mode, sizeof(int));
	if (err) {
		if ( debug_level >= DEBUG_LEVEL_INFO )
			printk( "%s(%d):%s get_txidle() user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}

	return 0;
}

static int set_txidle(SLMP_INFO * info, int idle_mode)
{
 	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):%s set_txidle(%d)\n",
			__FILE__,__LINE__,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 tx_enable(SLMP_INFO * info, int enable)
{
 	unsigned long flags;

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

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

/* abort send HDLC frame
 */
static int tx_abort(SLMP_INFO * info)
{
 	unsigned long flags;

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

	spin_lock_irqsave(&info->lock,flags);
	if ( info->tx_active && info->params.mode == MGSL_MODE_HDLC ) {
		info->ie1_value &= ~UDRN;
		info->ie1_value |= IDLE;
		write_reg(info, IE1, info->ie1_value);	/* disable tx status interrupts */
		write_reg(info, SR1, (unsigned char)(IDLE + UDRN));	/* clear pending */

		write_reg(info, TXDMA + DSR, 0);		/* disable DMA channel */
		write_reg(info, TXDMA + DCMD, SWABORT);	/* reset/init DMA channel */

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

static int rx_enable(SLMP_INFO * info, int enable)
{
 	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):%s rx_enable(%d)\n",
			__FILE__,__LINE__,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
 */
static int wait_mgsl_event(SLMP_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("%s(%d):%s wait_mgsl_event(%d)\n",
			__FILE__,__LINE__,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 &