drivers/tty/synclink.c

/*
 * $Id: synclink.c,v 4.38 2005/11/07 16:30:34 paulkf Exp $
 *
 * Device driver for Microgate SyncLink ISA and PCI
 * high speed multiprotocol serial adapters.
 *
 * 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
 *
 * Original release 01/11/99
 *
 * This code is released under the GNU General Public License (GPL)
 *
 * This driver is primarily intended for use in synchronous
 * HDLC mode. Asynchronous mode is also provided.
 *
 * When operating in synchronous mode, each call to mgsl_write()
 * contains exactly one complete HDLC frame. Calling mgsl_put_char
 * will start assembling an HDLC frame that will not be sent until
 * mgsl_flush_chars or mgsl_write is called.
 * 
 * Synchronous receive data is reported as complete frames. To accomplish
 * this, the TTY flip buffer is bypassed (too small to hold largest
 * frame and may fragment frames) and the line discipline
 * receive entry point is called directly.
 *
 * This driver has been tested with a slightly modified ppp.c driver
 * for synchronous PPP.
 *
 * 2000/02/16
 * Added interface for syncppp.c driver (an alternate synchronous PPP
 * implementation that also supports Cisco HDLC). Each device instance
 * registers as a tty device AND a network device (if dosyncppp option
 * is set for the device). The functionality is determined by which
 * device interface is opened.
 *
 * 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.
 */

#if defined(__i386__)
#  define BREAKPOINT() asm("   int $3");
#else
#  define BREAKPOINT() { }
#endif

#define MAX_ISA_DEVICES 10
#define MAX_PCI_DEVICES 10
#define MAX_TOTAL_DEVICES 20

#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/delay.h>
#include <linux/netdevice.h>
#include <linux/vmalloc.h>
#include <linux/init.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 <linux/dma-mapping.h>

#if defined(CONFIG_HDLC) || (defined(CONFIG_HDLC_MODULE) && defined(CONFIG_SYNCLINK_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>

#define RCLRVALUE 0xffff

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; */
};

#define SHARED_MEM_ADDRESS_SIZE 0x40000
#define BUFFERLISTSIZE 4096
#define DMABUFFERSIZE 4096
#define MAXRXFRAMES 7

typedef struct _DMABUFFERENTRY
{
	u32 phys_addr;	/* 32-bit flat physical address of data buffer */
	volatile u16 count;	/* buffer size/data count */
	volatile u16 status;	/* Control/status field */
	volatile u16 rcc;	/* character count field */
	u16 reserved;	/* padding required by 16C32 */
	u32 link;	/* 32-bit flat link to next buffer entry */
	char *virt_addr;	/* virtual address of data buffer */
	u32 phys_entry;	/* physical address of this buffer entry */
	dma_addr_t dma_addr;
} DMABUFFERENTRY, *DMAPBUFFERENTRY;

/* 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;
};

/* transmit holding buffer definitions*/
#define MAX_TX_HOLDING_BUFFERS 5
struct tx_holding_buffer {
	int	buffer_size;
	unsigned char *	buffer;
};


/*
 * Device instance data structure
 */
 
struct mgsl_struct {
	int			magic;
	struct tty_port		port;
	int			line;
	int                     hw_version;
	
	struct mgsl_icount	icount;
	
	int			timeout;
	int			x_char;		/* xon/xoff character */
	u16			read_status_mask;
	u16			ignore_status_mask;	
	unsigned char 		*xmit_buf;
	int			xmit_head;
	int			xmit_tail;
	int			xmit_cnt;
	
	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 mgsl_struct	*next_device;	/* device list link */
	
	spinlock_t irq_spinlock;		/* spinlock for synchronizing with ISR */
	struct work_struct task;		/* task structure for scheduling bh */

	u32 EventMask;			/* event trigger mask */
	u32 RecordedEvents;		/* pending events */

	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 */
	u32 buffer_list_phys;
	dma_addr_t buffer_list_dma_addr;

	unsigned int rx_buffer_count;	/* count of total allocated Rx buffers */
	DMABUFFERENTRY *rx_buffer_list;	/* list of receive buffer entries */
	unsigned int current_rx_buffer;

	int num_tx_dma_buffers;		/* number of tx dma frames required */
 	int tx_dma_buffers_used;
	unsigned int tx_buffer_count;	/* count of total allocated Tx buffers */
	DMABUFFERENTRY *tx_buffer_list;	/* list of transmit buffer entries */
	int start_tx_dma_buffer;	/* tx dma buffer to start tx dma operation */
	int current_tx_buffer;          /* next tx dma buffer to be loaded */
	
	unsigned char *intermediate_rxbuffer;

	int num_tx_holding_buffers;	/* number of tx holding buffer allocated */
	int get_tx_holding_index;  	/* next tx holding buffer for adapter to load */
	int put_tx_holding_index;  	/* next tx holding buffer to store user request */
	int tx_holding_count;		/* number of tx holding buffers waiting */
	struct tx_holding_buffer tx_holding_buffers[MAX_TX_HOLDING_BUFFERS];

	bool rx_enabled;
	bool rx_overflow;
	bool rx_rcc_underrun;

	bool tx_enabled;
	bool tx_active;
	u32 idle_mode;

	u16 cmr_value;
	u16 tcsr_value;

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

	unsigned int bus_type;	/* expansion bus type (ISA,EISA,PCI) */
	unsigned char bus;		/* expansion bus number (zero based) */
	unsigned char function;		/* PCI device number */

	unsigned int io_base;		/* base I/O address of adapter */
	unsigned int io_addr_size;	/* size of the I/O address range */
	bool io_addr_requested;		/* true if I/O address requested */
	
	unsigned int irq_level;		/* interrupt level */
	unsigned long irq_flags;
	bool irq_requested;		/* true if IRQ requested */
	
	unsigned int dma_level;		/* DMA channel */
	bool dma_requested;		/* true if dma channel requested */

	u16 mbre_bit;
	u16 loopback_bits;
	u16 usc_idle_mode;

	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 		(DIAGS)	*/
	int	fDiagnosticsmode;	/* Driver in Diagnostic mode?			(DIAGS)	*/

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

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

	u32 misc_ctrl_value;
	char *flag_buf;
	bool drop_rts_on_tx_done;

	bool loopmode_insert_requested;
	bool loopmode_send_done_requested;
	
	struct	_input_signal_events	input_signal_events;

	/* generic HDLC device parts */
	int netcount;
	spinlock_t netlock;

#if SYNCLINK_GENERIC_HDLC
	struct net_device *netdev;
#endif
};

#define MGSL_MAGIC 0x5401

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

/*
 * These macros define the offsets used in calculating the
 * I/O address of the specified USC registers.
 */


#define DCPIN 2		/* Bit 1 of I/O address */
#define SDPIN 4		/* Bit 2 of I/O address */

#define DCAR 0		/* DMA command/address register */
#define CCAR SDPIN		/* channel command/address register */
#define DATAREG DCPIN + SDPIN	/* serial data register */
#define MSBONLY 0x41
#define LSBONLY 0x40

/*
 * These macros define the register address (ordinal number)
 * used for writing address/value pairs to the USC.
 */

#define CMR	0x02	/* Channel mode Register */
#define CCSR	0x04	/* Channel Command/status Register */
#define CCR	0x06	/* Channel Control Register */
#define PSR	0x08	/* Port status Register */
#define PCR	0x0a	/* Port Control Register */
#define TMDR	0x0c	/* Test mode Data Register */
#define TMCR	0x0e	/* Test mode Control Register */
#define CMCR	0x10	/* Clock mode Control Register */
#define HCR	0x12	/* Hardware Configuration Register */
#define IVR	0x14	/* Interrupt Vector Register */
#define IOCR	0x16	/* Input/Output Control Register */
#define ICR	0x18	/* Interrupt Control Register */
#define DCCR	0x1a	/* Daisy Chain Control Register */
#define MISR	0x1c	/* Misc Interrupt status Register */
#define SICR	0x1e	/* status Interrupt Control Register */
#define RDR	0x20	/* Receive Data Register */
#define RMR	0x22	/* Receive mode Register */
#define RCSR	0x24	/* Receive Command/status Register */
#define RICR	0x26	/* Receive Interrupt Control Register */
#define RSR	0x28	/* Receive Sync Register */
#define RCLR	0x2a	/* Receive count Limit Register */
#define RCCR	0x2c	/* Receive Character count Register */
#define TC0R	0x2e	/* Time Constant 0 Register */
#define TDR	0x30	/* Transmit Data Register */
#define TMR	0x32	/* Transmit mode Register */
#define TCSR	0x34	/* Transmit Command/status Register */
#define TICR	0x36	/* Transmit Interrupt Control Register */
#define TSR	0x38	/* Transmit Sync Register */
#define TCLR	0x3a	/* Transmit count Limit Register */
#define TCCR	0x3c	/* Transmit Character count Register */
#define TC1R	0x3e	/* Time Constant 1 Register */


/*
 * MACRO DEFINITIONS FOR DMA REGISTERS
 */

#define DCR	0x06	/* DMA Control Register (shared) */
#define DACR	0x08	/* DMA Array count Register (shared) */
#define BDCR	0x12	/* Burst/Dwell Control Register (shared) */
#define DIVR	0x14	/* DMA Interrupt Vector Register (shared) */	
#define DICR	0x18	/* DMA Interrupt Control Register (shared) */
#define CDIR	0x1a	/* Clear DMA Interrupt Register (shared) */
#define SDIR	0x1c	/* Set DMA Interrupt Register (shared) */

#define TDMR	0x02	/* Transmit DMA mode Register */
#define TDIAR	0x1e	/* Transmit DMA Interrupt Arm Register */
#define TBCR	0x2a	/* Transmit Byte count Register */
#define TARL	0x2c	/* Transmit Address Register (low) */
#define TARU	0x2e	/* Transmit Address Register (high) */
#define NTBCR	0x3a	/* Next Transmit Byte count Register */
#define NTARL	0x3c	/* Next Transmit Address Register (low) */
#define NTARU	0x3e	/* Next Transmit Address Register (high) */

#define RDMR	0x82	/* Receive DMA mode Register (non-shared) */
#define RDIAR	0x9e	/* Receive DMA Interrupt Arm Register */
#define RBCR	0xaa	/* Receive Byte count Register */
#define RARL	0xac	/* Receive Address Register (low) */
#define RARU	0xae	/* Receive Address Register (high) */
#define NRBCR	0xba	/* Next Receive Byte count Register */
#define NRARL	0xbc	/* Next Receive Address Register (low) */
#define NRARU	0xbe	/* Next Receive Address Register (high) */


/*
 * MACRO DEFINITIONS FOR MODEM STATUS BITS
 */

#define MODEMSTATUS_DTR 0x80
#define MODEMSTATUS_DSR 0x40
#define MODEMSTATUS_RTS 0x20
#define MODEMSTATUS_CTS 0x10
#define MODEMSTATUS_RI  0x04
#define MODEMSTATUS_DCD 0x01


/*
 * Channel Command/Address Register (CCAR) Command Codes
 */

#define RTCmd_Null			0x0000
#define RTCmd_ResetHighestIus		0x1000
#define RTCmd_TriggerChannelLoadDma	0x2000
#define RTCmd_TriggerRxDma		0x2800
#define RTCmd_TriggerTxDma		0x3000
#define RTCmd_TriggerRxAndTxDma		0x3800
#define RTCmd_PurgeRxFifo		0x4800
#define RTCmd_PurgeTxFifo		0x5000
#define RTCmd_PurgeRxAndTxFifo		0x5800
#define RTCmd_LoadRcc			0x6800
#define RTCmd_LoadTcc			0x7000
#define RTCmd_LoadRccAndTcc		0x7800
#define RTCmd_LoadTC0			0x8800
#define RTCmd_LoadTC1			0x9000
#define RTCmd_LoadTC0AndTC1		0x9800
#define RTCmd_SerialDataLSBFirst	0xa000
#define RTCmd_SerialDataMSBFirst	0xa800
#define RTCmd_SelectBigEndian		0xb000
#define RTCmd_SelectLittleEndian	0xb800


/*
 * DMA Command/Address Register (DCAR) Command Codes
 */

#define DmaCmd_Null			0x0000
#define DmaCmd_ResetTxChannel		0x1000
#define DmaCmd_ResetRxChannel		0x1200
#define DmaCmd_StartTxChannel		0x2000
#define DmaCmd_StartRxChannel		0x2200
#define DmaCmd_ContinueTxChannel	0x3000
#define DmaCmd_ContinueRxChannel	0x3200
#define DmaCmd_PauseTxChannel		0x4000
#define DmaCmd_PauseRxChannel		0x4200
#define DmaCmd_AbortTxChannel		0x5000
#define DmaCmd_AbortRxChannel		0x5200
#define DmaCmd_InitTxChannel		0x7000
#define DmaCmd_InitRxChannel		0x7200
#define DmaCmd_ResetHighestDmaIus	0x8000
#define DmaCmd_ResetAllChannels		0x9000
#define DmaCmd_StartAllChannels		0xa000
#define DmaCmd_ContinueAllChannels	0xb000
#define DmaCmd_PauseAllChannels		0xc000
#define DmaCmd_AbortAllChannels		0xd000
#define DmaCmd_InitAllChannels		0xf000

#define TCmd_Null			0x0000
#define TCmd_ClearTxCRC			0x2000
#define TCmd_SelectTicrTtsaData		0x4000
#define TCmd_SelectTicrTxFifostatus	0x5000
#define TCmd_SelectTicrIntLevel		0x6000
#define TCmd_SelectTicrdma_level		0x7000
#define TCmd_SendFrame			0x8000
#define TCmd_SendAbort			0x9000
#define TCmd_EnableDleInsertion		0xc000
#define TCmd_DisableDleInsertion	0xd000
#define TCmd_ClearEofEom		0xe000
#define TCmd_SetEofEom			0xf000

#define RCmd_Null			0x0000
#define RCmd_ClearRxCRC			0x2000
#define RCmd_EnterHuntmode		0x3000
#define RCmd_SelectRicrRtsaData		0x4000
#define RCmd_SelectRicrRxFifostatus	0x5000
#define RCmd_SelectRicrIntLevel		0x6000
#define RCmd_SelectRicrdma_level		0x7000

/*
 * Bits for enabling and disabling IRQs in Interrupt Control Register (ICR)
 */
 
#define RECEIVE_STATUS		BIT5
#define RECEIVE_DATA		BIT4
#define TRANSMIT_STATUS		BIT3
#define TRANSMIT_DATA		BIT2
#define IO_PIN			BIT1
#define MISC			BIT0


/*
 * Receive status Bits in Receive Command/status Register RCSR
 */

#define RXSTATUS_SHORT_FRAME		BIT8
#define RXSTATUS_CODE_VIOLATION		BIT8
#define RXSTATUS_EXITED_HUNT		BIT7
#define RXSTATUS_IDLE_RECEIVED		BIT6
#define RXSTATUS_BREAK_RECEIVED		BIT5
#define RXSTATUS_ABORT_RECEIVED		BIT5
#define RXSTATUS_RXBOUND		BIT4
#define RXSTATUS_CRC_ERROR		BIT3
#define RXSTATUS_FRAMING_ERROR		BIT3
#define RXSTATUS_ABORT			BIT2
#define RXSTATUS_PARITY_ERROR		BIT2
#define RXSTATUS_OVERRUN		BIT1
#define RXSTATUS_DATA_AVAILABLE		BIT0
#define RXSTATUS_ALL			0x01f6
#define usc_UnlatchRxstatusBits(a,b) usc_OutReg( (a), RCSR, (u16)((b) & RXSTATUS_ALL) )

/*
 * Values for setting transmit idle mode in 
 * Transmit Control/status Register (TCSR)
 */
#define IDLEMODE_FLAGS			0x0000
#define IDLEMODE_ALT_ONE_ZERO		0x0100
#define IDLEMODE_ZERO			0x0200
#define IDLEMODE_ONE			0x0300
#define IDLEMODE_ALT_MARK_SPACE		0x0500
#define IDLEMODE_SPACE			0x0600
#define IDLEMODE_MARK			0x0700
#define IDLEMODE_MASK			0x0700

/*
 * IUSC revision identifiers
 */
#define	IUSC_SL1660			0x4d44
#define IUSC_PRE_SL1660			0x4553

/*
 * Transmit status Bits in Transmit Command/status Register (TCSR)
 */

#define TCSR_PRESERVE			0x0F00

#define TCSR_UNDERWAIT			BIT11
#define TXSTATUS_PREAMBLE_SENT		BIT7
#define TXSTATUS_IDLE_SENT		BIT6
#define TXSTATUS_ABORT_SENT		BIT5
#define TXSTATUS_EOF_SENT		BIT4
#define TXSTATUS_EOM_SENT		BIT4
#define TXSTATUS_CRC_SENT		BIT3
#define TXSTATUS_ALL_SENT		BIT2
#define TXSTATUS_UNDERRUN		BIT1
#define TXSTATUS_FIFO_EMPTY		BIT0
#define TXSTATUS_ALL			0x00fa
#define usc_UnlatchTxstatusBits(a,b) usc_OutReg( (a), TCSR, (u16)((a)->tcsr_value + ((b) & 0x00FF)) )
				

#define MISCSTATUS_RXC_LATCHED		BIT15
#define MISCSTATUS_RXC			BIT14
#define MISCSTATUS_TXC_LATCHED		BIT13
#define MISCSTATUS_TXC			BIT12
#define MISCSTATUS_RI_LATCHED		BIT11
#define MISCSTATUS_RI			BIT10
#define MISCSTATUS_DSR_LATCHED		BIT9
#define MISCSTATUS_DSR			BIT8
#define MISCSTATUS_DCD_LATCHED		BIT7
#define MISCSTATUS_DCD			BIT6
#define MISCSTATUS_CTS_LATCHED		BIT5
#define MISCSTATUS_CTS			BIT4
#define MISCSTATUS_RCC_UNDERRUN		BIT3
#define MISCSTATUS_DPLL_NO_SYNC		BIT2
#define MISCSTATUS_BRG1_ZERO		BIT1
#define MISCSTATUS_BRG0_ZERO		BIT0

#define usc_UnlatchIostatusBits(a,b) usc_OutReg((a),MISR,(u16)((b) & 0xaaa0))
#define usc_UnlatchMiscstatusBits(a,b) usc_OutReg((a),MISR,(u16)((b) & 0x000f))

#define SICR_RXC_ACTIVE			BIT15
#define SICR_RXC_INACTIVE		BIT14
#define SICR_RXC			(BIT15|BIT14)
#define SICR_TXC_ACTIVE			BIT13
#define SICR_TXC_INACTIVE		BIT12
#define SICR_TXC			(BIT13|BIT12)
#define SICR_RI_ACTIVE			BIT11
#define SICR_RI_INACTIVE		BIT10
#define SICR_RI				(BIT11|BIT10)
#define SICR_DSR_ACTIVE			BIT9
#define SICR_DSR_INACTIVE		BIT8
#define SICR_DSR			(BIT9|BIT8)
#define SICR_DCD_ACTIVE			BIT7
#define SICR_DCD_INACTIVE		BIT6
#define SICR_DCD			(BIT7|BIT6)
#define SICR_CTS_ACTIVE			BIT5
#define SICR_CTS_INACTIVE		BIT4
#define SICR_CTS			(BIT5|BIT4)
#define SICR_RCC_UNDERFLOW		BIT3
#define SICR_DPLL_NO_SYNC		BIT2
#define SICR_BRG1_ZERO			BIT1
#define SICR_BRG0_ZERO			BIT0

void usc_DisableMasterIrqBit( struct mgsl_struct *info );
void usc_EnableMasterIrqBit( struct mgsl_struct *info );
void usc_EnableInterrupts( struct mgsl_struct *info, u16 IrqMask );
void usc_DisableInterrupts( struct mgsl_struct *info, u16 IrqMask );
void usc_ClearIrqPendingBits( struct mgsl_struct *info, u16 IrqMask );

#define usc_EnableInterrupts( a, b ) \
	usc_OutReg( (a), ICR, (u16)((usc_InReg((a),ICR) & 0xff00) + 0xc0 + (b)) )

#define usc_DisableInterrupts( a, b ) \
	usc_OutReg( (a), ICR, (u16)((usc_InReg((a),ICR) & 0xff00) + 0x80 + (b)) )

#define usc_EnableMasterIrqBit(a) \
	usc_OutReg( (a), ICR, (u16)((usc_InReg((a),ICR) & 0x0f00) + 0xb000) )

#define usc_DisableMasterIrqBit(a) \
	usc_OutReg( (a), ICR, (u16)(usc_InReg((a),ICR) & 0x7f00) )

#define usc_ClearIrqPendingBits( a, b ) usc_OutReg( (a), DCCR, 0x40 + (b) )

/*
 * Transmit status Bits in Transmit Control status Register (TCSR)
 * and Transmit Interrupt Control Register (TICR) (except BIT2, BIT0)
 */

#define TXSTATUS_PREAMBLE_SENT	BIT7
#define TXSTATUS_IDLE_SENT	BIT6
#define TXSTATUS_ABORT_SENT	BIT5
#define TXSTATUS_EOF		BIT4
#define TXSTATUS_CRC_SENT	BIT3
#define TXSTATUS_ALL_SENT	BIT2
#define TXSTATUS_UNDERRUN	BIT1
#define TXSTATUS_FIFO_EMPTY	BIT0

#define DICR_MASTER		BIT15
#define DICR_TRANSMIT		BIT0
#define DICR_RECEIVE		BIT1

#define usc_EnableDmaInterrupts(a,b) \
	usc_OutDmaReg( (a), DICR, (u16)(usc_InDmaReg((a),DICR) | (b)) )

#define usc_DisableDmaInterrupts(a,b) \
	usc_OutDmaReg( (a), DICR, (u16)(usc_InDmaReg((a),DICR) & ~(b)) )

#define usc_EnableStatusIrqs(a,b) \
	usc_OutReg( (a), SICR, (u16)(usc_InReg((a),SICR) | (b)) )

#define usc_DisablestatusIrqs(a,b) \
	usc_OutReg( (a), SICR, (u16)(usc_InReg((a),SICR) & ~(b)) )

/* Transmit status Bits in Transmit Control status Register (TCSR) */
/* and Transmit Interrupt Control Register (TICR) (except BIT2, BIT0) */


#define DISABLE_UNCONDITIONAL    0
#define DISABLE_END_OF_FRAME     1
#define ENABLE_UNCONDITIONAL     2
#define ENABLE_AUTO_CTS          3
#define ENABLE_AUTO_DCD          3
#define usc_EnableTransmitter(a,b) \
	usc_OutReg( (a), TMR, (u16)((usc_InReg((a),TMR) & 0xfffc) | (b)) )
#define usc_EnableReceiver(a,b) \
	usc_OutReg( (a), RMR, (u16)((usc_InReg((a),RMR) & 0xfffc) | (b)) )

static u16  usc_InDmaReg( struct mgsl_struct *info, u16 Port );
static void usc_OutDmaReg( struct mgsl_struct *info, u16 Port, u16 Value );
static void usc_DmaCmd( struct mgsl_struct *info, u16 Cmd );

static u16  usc_InReg( struct mgsl_struct *info, u16 Port );
static void usc_OutReg( struct mgsl_struct *info, u16 Port, u16 Value );
static void usc_RTCmd( struct mgsl_struct *info, u16 Cmd );
void usc_RCmd( struct mgsl_struct *info, u16 Cmd );
void usc_TCmd( struct mgsl_struct *info, u16 Cmd );

#define usc_TCmd(a,b) usc_OutReg((a), TCSR, (u16)((a)->tcsr_value + (b)))
#define usc_RCmd(a,b) usc_OutReg((a), RCSR, (b))

#define usc_SetTransmitSyncChars(a,s0,s1) usc_OutReg((a), TSR, (u16)(((u16)s0<<8)|(u16)s1))

static void usc_process_rxoverrun_sync( struct mgsl_struct *info );
static void usc_start_receiver( struct mgsl_struct *info );
static void usc_stop_receiver( struct mgsl_struct *info );

static void usc_start_transmitter( struct mgsl_struct *info );
static void usc_stop_transmitter( struct mgsl_struct *info );
static void usc_set_txidle( struct mgsl_struct *info );
static void usc_load_txfifo( struct mgsl_struct *info );

static void usc_enable_aux_clock( struct mgsl_struct *info, u32 DataRate );
static void usc_enable_loopback( struct mgsl_struct *info, int enable );

static void usc_get_serial_signals( struct mgsl_struct *info );
static void usc_set_serial_signals( struct mgsl_struct *info );

static void usc_reset( struct mgsl_struct *info );

static void usc_set_sync_mode( struct mgsl_struct *info );
static void usc_set_sdlc_mode( struct mgsl_struct *info );
static void usc_set_async_mode( struct mgsl_struct *info );
static void usc_enable_async_clock( struct mgsl_struct *info, u32 DataRate );

static void usc_loopback_frame( struct mgsl_struct *info );

static void mgsl_tx_timeout(unsigned long context);


static void usc_loopmode_cancel_transmit( struct mgsl_struct * info );
static void usc_loopmode_insert_request( struct mgsl_struct * info );
static int usc_loopmode_active( struct mgsl_struct * info);
static void usc_loopmode_send_done( struct mgsl_struct * info );

static int mgsl_ioctl_common(struct mgsl_struct *info, unsigned int cmd, unsigned long arg);

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

/*
 * Defines a BUS descriptor value for the PCI adapter
 * local bus address ranges.
 */

#define BUS_DESCRIPTOR( WrHold, WrDly, RdDly, Nwdd, Nwad, Nxda, Nrdd, Nrad ) \
(0x00400020 + \
((WrHold) << 30) + \
((WrDly)  << 28) + \
((RdDly)  << 26) + \
((Nwdd)   << 20) + \
((Nwad)   << 15) + \
((Nxda)   << 13) + \
((Nrdd)   << 11) + \
((Nrad)   <<  6) )

static void mgsl_trace_block(struct mgsl_struct *info,const char* data, int count, int xmit);

/*
 * Adapter diagnostic routines
 */
static bool mgsl_register_test( struct mgsl_struct *info );
static bool mgsl_irq_test( struct mgsl_struct *info );
static bool mgsl_dma_test( struct mgsl_struct *info );
static bool mgsl_memory_test( struct mgsl_struct *info );
static int mgsl_adapter_test( struct mgsl_struct *info );

/*
 * device and resource management routines
 */
static int mgsl_claim_resources(struct mgsl_struct *info);
static void mgsl_release_resources(struct mgsl_struct *info);
static void mgsl_add_device(struct mgsl_struct *info);
static struct mgsl_struct* mgsl_allocate_device(void);

/*
 * DMA buffer manupulation functions.
 */
static void mgsl_free_rx_frame_buffers( struct mgsl_struct *info, unsigned int StartIndex, unsigned int EndIndex );
static bool mgsl_get_rx_frame( struct mgsl_struct *info );
static bool mgsl_get_raw_rx_frame( struct mgsl_struct *info );
static void mgsl_reset_rx_dma_buffers( struct mgsl_struct *info );
static void mgsl_reset_tx_dma_buffers( struct mgsl_struct *info );
static int num_free_tx_dma_buffers(struct mgsl_struct *info);
static void mgsl_load_tx_dma_buffer( struct mgsl_struct *info, const char *Buffer, unsigned int BufferSize);
static void mgsl_load_pci_memory(char* TargetPtr, const char* SourcePtr, unsigned short count);

/*
 * DMA and Shared Memory buffer allocation and formatting
 */
static int  mgsl_allocate_dma_buffers(struct mgsl_struct *info);
static void mgsl_free_dma_buffers(struct mgsl_struct *info);
static int  mgsl_alloc_frame_memory(struct mgsl_struct *info, DMABUFFERENTRY *BufferList,int Buffercount);
static void mgsl_free_frame_memory(struct mgsl_struct *info, DMABUFFERENTRY *BufferList,int Buffercount);
static int  mgsl_alloc_buffer_list_memory(struct mgsl_struct *info);
static void mgsl_free_buffer_list_memory(struct mgsl_struct *info);
static int mgsl_alloc_intermediate_rxbuffer_memory(struct mgsl_struct *info);
static void mgsl_free_intermediate_rxbuffer_memory(struct mgsl_struct *info);
static int mgsl_alloc_intermediate_txbuffer_memory(struct mgsl_struct *info);
static void mgsl_free_intermediate_txbuffer_memory(struct mgsl_struct *info);
static bool load_next_tx_holding_buffer(struct mgsl_struct *info);
static int save_tx_buffer_request(struct mgsl_struct *info,const char *Buffer, unsigned int BufferSize);

/*
 * Bottom half interrupt handlers
 */
static void mgsl_bh_handler(struct work_struct *work);
static void mgsl_bh_receive(struct mgsl_struct *info);
static void mgsl_bh_transmit(struct mgsl_struct *info);
static void mgsl_bh_status(struct mgsl_struct *info);

/*
 * Interrupt handler routines and dispatch table.
 */
static void mgsl_isr_null( struct mgsl_struct *info );
static void mgsl_isr_transmit_data( struct mgsl_struct *info );
static void mgsl_isr_receive_data( struct mgsl_struct *info );
static void mgsl_isr_receive_status( struct mgsl_struct *info );
static void mgsl_isr_transmit_status( struct mgsl_struct *info );
static void mgsl_isr_io_pin( struct mgsl_struct *info );
static void mgsl_isr_misc( struct mgsl_struct *info );
static void mgsl_isr_receive_dma( struct mgsl_struct *info );
static void mgsl_isr_transmit_dma( struct mgsl_struct *info );

typedef void (*isr_dispatch_func)(struct mgsl_struct *);

static isr_dispatch_func UscIsrTable[7] =
{
	mgsl_isr_null,
	mgsl_isr_misc,
	mgsl_isr_io_pin,
	mgsl_isr_transmit_data,
	mgsl_isr_transmit_status,
	mgsl_isr_receive_data,
	mgsl_isr_receive_status
};

/*
 * ioctl call handlers
 */
static int tiocmget(struct tty_struct *tty);
static int tiocmset(struct tty_struct *tty,
		    unsigned int set, unsigned int clear);
static int mgsl_get_stats(struct mgsl_struct * info, struct mgsl_icount
	__user *user_icount);
static int mgsl_get_params(struct mgsl_struct * info, MGSL_PARAMS  __user *user_params);
static int mgsl_set_params(struct mgsl_struct * info, MGSL_PARAMS  __user *new_params);
static int mgsl_get_txidle(struct mgsl_struct * info, int __user *idle_mode);
static int mgsl_set_txidle(struct mgsl_struct * info, int idle_mode);
static int mgsl_txenable(struct mgsl_struct * info, int enable);
static int mgsl_txabort(struct mgsl_struct * info);
static int mgsl_rxenable(struct mgsl_struct * info, int enable);
static int mgsl_wait_event(struct mgsl_struct * info, int __user *mask);
static int mgsl_loopmode_send_done( struct mgsl_struct * info );

/* set non-zero on successful registration with PCI subsystem */
static bool pci_registered;

/*
 * Global linked list of SyncLink devices
 */
static struct mgsl_struct *mgsl_device_list;
static int mgsl_device_count;

/*
 * 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;

/*
 * Array of user specified options for ISA adapters.
 */
static int io[MAX_ISA_DEVICES];
static int irq[MAX_ISA_DEVICES];
static int dma[MAX_ISA_DEVICES];
static int debug_level;
static int maxframe[MAX_TOTAL_DEVICES];
static int txdmabufs[MAX_TOTAL_DEVICES];
static int txholdbufs[MAX_TOTAL_DEVICES];
	
module_param(break_on_load, bool, 0);
module_param(ttymajor, int, 0);
module_param_hw_array(io, int, ioport, NULL, 0);
module_param_hw_array(irq, int, irq, NULL, 0);
module_param_hw_array(dma, int, dma, NULL, 0);
module_param(debug_level, int, 0);
module_param_array(maxframe, int, NULL, 0);
module_param_array(txdmabufs, int, NULL, 0);
module_param_array(txholdbufs, int, NULL, 0);

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

static int synclink_init_one (struct pci_dev *dev,
				     const struct pci_device_id *ent);
static void synclink_remove_one (struct pci_dev *dev);

static const struct pci_device_id synclink_pci_tbl[] = {
	{ PCI_VENDOR_ID_MICROGATE, PCI_DEVICE_ID_MICROGATE_USC, PCI_ANY_ID, PCI_ANY_ID, },
	{ PCI_VENDOR_ID_MICROGATE, 0x0210, PCI_ANY_ID, PCI_ANY_ID, },
	{ 0, }, /* terminate list */
};
MODULE_DEVICE_TABLE(pci, synclink_pci_tbl);

MODULE_LICENSE("GPL");

static struct pci_driver synclink_pci_driver = {
	.name		= "synclink",
	.id_table	= synclink_pci_tbl,
	.probe		= synclink_init_one,
	.remove		= synclink_remove_one,
};

static struct tty_driver *serial_driver;

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


static void mgsl_change_params(struct mgsl_struct *info);
static void mgsl_wait_until_sent(struct tty_struct *tty, int timeout);

/*
 * 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* mgsl_get_text_ptr(void)
{
	return mgsl_get_text_ptr;
}

static inline int mgsl_paranoia_check(struct mgsl_struct *info,
					char *name, const char *routine)
{
#ifdef MGSL_PARANOIA_CHECK
	static const char *badmagic =
		"Warning: bad magic number for mgsl struct (%s) in %s\n";
	static const char *badinfo =
		"Warning: null mgsl_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);
	}
}

/* mgsl_stop()		throttle (stop) transmitter
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_stop(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_stop"))
		return;
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk("mgsl_stop(%s)\n",info->device_name);	
		
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if (info->tx_enabled)
	 	usc_stop_transmitter(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
}	/* end of mgsl_stop() */

/* mgsl_start()		release (start) transmitter
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_start(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_start"))
		return;
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk("mgsl_start(%s)\n",info->device_name);	
		
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if (!info->tx_enabled)
	 	usc_start_transmitter(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
}	/* end of mgsl_start() */

/*
 * Bottom half work queue access functions
 */

/* mgsl_bh_action()	Return next bottom half action to perform.
 * Return Value:	BH action code or 0 if nothing to do.
 */
static int mgsl_bh_action(struct mgsl_struct *info)
{
	unsigned long flags;
	int rc = 0;
	
	spin_lock_irqsave(&info->irq_spinlock,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->irq_spinlock,flags);
	
	return rc;
}

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

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

	while((action = mgsl_bh_action(info)) != 0) {
	
		/* Process work item */
		if ( debug_level >= DEBUG_LEVEL_BH )
			printk( "%s(%d):mgsl_bh_handler() work item action=%d\n",
				__FILE__,__LINE__,action);

		switch (action) {
		
		case BH_RECEIVE:
			mgsl_bh_receive(info);
			break;
		case BH_TRANSMIT:
			mgsl_bh_transmit(info);
			break;
		case BH_STATUS:
			mgsl_bh_status(info);
			break;
		default:
			/* unknown work item ID */
			printk("Unknown work item ID=%08X!\n", action);
			break;
		}
	}

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

static void mgsl_bh_receive(struct mgsl_struct *info)
{
	bool (*get_rx_frame)(struct mgsl_struct *info) =
		(info->params.mode == MGSL_MODE_HDLC ? mgsl_get_rx_frame : mgsl_get_raw_rx_frame);

	if ( debug_level >= DEBUG_LEVEL_BH )
		printk( "%s(%d):mgsl_bh_receive(%s)\n",
			__FILE__,__LINE__,info->device_name);
	
	do
	{
		if (info->rx_rcc_underrun) {
			unsigned long flags;
			spin_lock_irqsave(&info->irq_spinlock,flags);
			usc_start_receiver(info);
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
			return;
		}
	} while(get_rx_frame(info));
}

static void mgsl_bh_transmit(struct mgsl_struct *info)
{
	struct tty_struct *tty = info->port.tty;
	unsigned long flags;
	
	if ( debug_level >= DEBUG_LEVEL_BH )
		printk( "%s(%d):mgsl_bh_transmit() entry on %s\n",
			__FILE__,__LINE__,info->device_name);

	if (tty)
		tty_wakeup(tty);

	/* if transmitter idle and loopmode_send_done_requested
	 * then start echoing RxD to TxD
	 */
	spin_lock_irqsave(&info->irq_spinlock,flags);
 	if ( !info->tx_active && info->loopmode_send_done_requested )
 		usc_loopmode_send_done( info );
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
}

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

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

/* mgsl_isr_receive_status()
 * 
 *	Service a receive status interrupt. The type of status
 *	interrupt is indicated by the state of the RCSR.
 *	This is only used for HDLC mode.
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_receive_status( struct mgsl_struct *info )
{
	u16 status = usc_InReg( info, RCSR );

	if ( debug_level >= DEBUG_LEVEL_ISR )
		printk("%s(%d):mgsl_isr_receive_status status=%04X\n",
			__FILE__,__LINE__,status);
			
 	if ( (status & RXSTATUS_ABORT_RECEIVED) && 
		info->loopmode_insert_requested &&
 		usc_loopmode_active(info) )
 	{
		++info->icount.rxabort;
	 	info->loopmode_insert_requested = false;
 
 		/* clear CMR:13 to start echoing RxD to TxD */
		info->cmr_value &= ~BIT13;
 		usc_OutReg(info, CMR, info->cmr_value);
 
		/* disable received abort irq (no longer required) */
	 	usc_OutReg(info, RICR,
 			(usc_InReg(info, RICR) & ~RXSTATUS_ABORT_RECEIVED));
 	}

	if (status & (RXSTATUS_EXITED_HUNT | RXSTATUS_IDLE_RECEIVED)) {
		if (status & RXSTATUS_EXITED_HUNT)
			info->icount.exithunt++;
		if (status & RXSTATUS_IDLE_RECEIVED)
			info->icount.rxidle++;
		wake_up_interruptible(&info->event_wait_q);
	}

	if (status & RXSTATUS_OVERRUN){
		info->icount.rxover++;
		usc_process_rxoverrun_sync( info );
	}

	usc_ClearIrqPendingBits( info, RECEIVE_STATUS );
	usc_UnlatchRxstatusBits( info, status );

}	/* end of mgsl_isr_receive_status() */

/* mgsl_isr_transmit_status()
 * 
 * 	Service a transmit status interrupt
 *	HDLC mode :end of transmit frame
 *	Async mode:all data is sent
 * 	transmit status is indicated by bits in the TCSR.
 * 
 * Arguments:		info	       pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_transmit_status( struct mgsl_struct *info )
{
	u16 status = usc_InReg( info, TCSR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_transmit_status status=%04X\n",
			__FILE__,__LINE__,status);
	
	usc_ClearIrqPendingBits( info, TRANSMIT_STATUS );
	usc_UnlatchTxstatusBits( info, status );
	
	if ( status & (TXSTATUS_UNDERRUN | TXSTATUS_ABORT_SENT) )
	{
		/* finished sending HDLC abort. This may leave	*/
		/* the TxFifo with data from the aborted frame	*/
		/* so purge the TxFifo. Also shutdown the DMA	*/
		/* channel in case there is data remaining in 	*/
		/* the DMA buffer				*/
 		usc_DmaCmd( info, DmaCmd_ResetTxChannel );
 		usc_RTCmd( info, RTCmd_PurgeTxFifo );
	}
 
	if ( status & TXSTATUS_EOF_SENT )
		info->icount.txok++;
	else if ( status & TXSTATUS_UNDERRUN )
		info->icount.txunder++;
	else if ( status & TXSTATUS_ABORT_SENT )
		info->icount.txabort++;
	else
		info->icount.txunder++;
			
	info->tx_active = false;
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	del_timer(&info->tx_timer);	
	
	if ( info->drop_rts_on_tx_done ) {
		usc_get_serial_signals( info );
		if ( info->serial_signals & SerialSignal_RTS ) {
			info->serial_signals &= ~SerialSignal_RTS;
			usc_set_serial_signals( info );
		}
		info->drop_rts_on_tx_done = false;
	}

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

}	/* end of mgsl_isr_transmit_status() */

/* mgsl_isr_io_pin()
 * 
 * 	Service an Input/Output pin interrupt. The type of
 * 	interrupt is indicated by bits in the MISR
 * 	
 * Arguments:		info	       pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_io_pin( struct mgsl_struct *info )
{
 	struct	mgsl_icount *icount;
	u16 status = usc_InReg( info, MISR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_io_pin status=%04X\n",
			__FILE__,__LINE__,status);
			
	usc_ClearIrqPendingBits( info, IO_PIN );
	usc_UnlatchIostatusBits( info, 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) {
			if ((info->ri_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
				usc_DisablestatusIrqs(info,SICR_RI);
			icount->rng++;
			if ( status & MISCSTATUS_RI )
				info->input_signal_events.ri_up++;	
			else
				info->input_signal_events.ri_down++;	
		}
		if (status & MISCSTATUS_DSR_LATCHED) {
			if ((info->dsr_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
				usc_DisablestatusIrqs(info,SICR_DSR);
			icount->dsr++;
			if ( status & MISCSTATUS_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)
				usc_DisablestatusIrqs(info,SICR_DCD);
			icount->dcd++;
			if (status & MISCSTATUS_DCD) {
				info->input_signal_events.dcd_up++;
			} else
				info->input_signal_events.dcd_down++;
#if SYNCLINK_GENERIC_HDLC
			if (info->netcount) {
				if (status & MISCSTATUS_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)
				usc_DisablestatusIrqs(info,SICR_CTS);
			icount->cts++;
			if ( status & MISCSTATUS_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_port_check_carrier(&info->port) &&
		     (status & MISCSTATUS_DCD_LATCHED) ) {
			if ( debug_level >= DEBUG_LEVEL_ISR )
				printk("%s CD now %s...", info->device_name,
				       (status & MISCSTATUS_DCD) ? "on" : "off");
			if (status & MISCSTATUS_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 (tty_port_cts_enabled(&info->port) &&
		     (status & MISCSTATUS_CTS_LATCHED) ) {
			if (info->port.tty->hw_stopped) {
				if (status & MISCSTATUS_CTS) {
					if ( debug_level >= DEBUG_LEVEL_ISR )
						printk("CTS tx start...");
					info->port.tty->hw_stopped = 0;
					usc_start_transmitter(info);
					info->pending_bh |= BH_TRANSMIT;
					return;
				}
			} else {
				if (!(status & MISCSTATUS_CTS)) {
					if ( debug_level >= DEBUG_LEVEL_ISR )
						printk("CTS tx stop...");
					if (info->port.tty)
						info->port.tty->hw_stopped = 1;
					usc_stop_transmitter(info);
				}
			}
		}
	}

	info->pending_bh |= BH_STATUS;
	
	/* for diagnostics set IRQ flag */
	if ( status & MISCSTATUS_TXC_LATCHED ){
		usc_OutReg( info, SICR,
			(unsigned short)(usc_InReg(info,SICR) & ~(SICR_TXC_ACTIVE+SICR_TXC_INACTIVE)) );
		usc_UnlatchIostatusBits( info, MISCSTATUS_TXC_LATCHED );
		info->irq_occurred = true;
	}

}	/* end of mgsl_isr_io_pin() */

/* mgsl_isr_transmit_data()
 * 
 * 	Service a transmit data interrupt (async mode only).
 * 
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_transmit_data( struct mgsl_struct *info )
{
	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_transmit_data xmit_cnt=%d\n",
			__FILE__,__LINE__,info->xmit_cnt);
			
	usc_ClearIrqPendingBits( info, TRANSMIT_DATA );
	
	if (info->port.tty->stopped || info->port.tty->hw_stopped) {
		usc_stop_transmitter(info);
		return;
	}
	
	if ( info->xmit_cnt )
		usc_load_txfifo( info );
	else
		info->tx_active = false;
		
	if (info->xmit_cnt < WAKEUP_CHARS)
		info->pending_bh |= BH_TRANSMIT;

}	/* end of mgsl_isr_transmit_data() */

/* mgsl_isr_receive_data()
 * 
 * 	Service a receive data interrupt. This occurs
 * 	when operating in asynchronous interrupt transfer mode.
 *	The receive data FIFO is flushed to the receive data buffers. 
 * 
 * Arguments:		info		pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_receive_data( struct mgsl_struct *info )
{
	int Fifocount;
	u16 status;
	int work = 0;
	unsigned char DataByte;
 	struct	mgsl_icount *icount = &info->icount;
	
	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_receive_data\n",
			__FILE__,__LINE__);

	usc_ClearIrqPendingBits( info, RECEIVE_DATA );
	
	/* select FIFO status for RICR readback */
	usc_RCmd( info, RCmd_SelectRicrRxFifostatus );

	/* clear the Wordstatus bit so that status readback */
	/* only reflects the status of this byte */
	usc_OutReg( info, RICR+LSBONLY, (u16)(usc_InReg(info, RICR+LSBONLY) & ~BIT3 ));

	/* flush the receive FIFO */

	while( (Fifocount = (usc_InReg(info,RICR) >> 8)) ) {
		int flag;

		/* read one byte from RxFIFO */
		outw( (inw(info->io_base + CCAR) & 0x0780) | (RDR+LSBONLY),
		      info->io_base + CCAR );
		DataByte = inb( info->io_base + CCAR );

		/* get the status of the received byte */
		status = usc_InReg(info, RCSR);
		if ( status & (RXSTATUS_FRAMING_ERROR | RXSTATUS_PARITY_ERROR |
				RXSTATUS_OVERRUN | RXSTATUS_BREAK_RECEIVED) )
			usc_UnlatchRxstatusBits(info,RXSTATUS_ALL);
		
		icount->rx++;
		
		flag = 0;
		if ( status & (RXSTATUS_FRAMING_ERROR | RXSTATUS_PARITY_ERROR |
				RXSTATUS_OVERRUN | RXSTATUS_BREAK_RECEIVED) ) {
			printk("rxerr=%04X\n",status);
			/* update error statistics */
			if ( status & RXSTATUS_BREAK_RECEIVED ) {
				status &= ~(RXSTATUS_FRAMING_ERROR | RXSTATUS_PARITY_ERROR);
				icount->brk++;
			} else if (status & RXSTATUS_PARITY_ERROR)
				icount->parity++;
			else if (status & RXSTATUS_FRAMING_ERROR)
				icount->frame++;
			else if (status & RXSTATUS_OVERRUN) {
				/* must issue purge fifo cmd before */
				/* 16C32 accepts more receive chars */
				usc_RTCmd(info,RTCmd_PurgeRxFifo);
				icount->overrun++;
			}

			/* discard char if tty control flags say so */
			if (status & info->ignore_status_mask)
				continue;
				
			status &= info->read_status_mask;
		
			if (status & RXSTATUS_BREAK_RECEIVED) {
				flag = TTY_BREAK;
				if (info->port.flags & ASYNC_SAK)
					do_SAK(info->port.tty);
			} else if (status & RXSTATUS_PARITY_ERROR)
				flag = TTY_PARITY;
			else if (status & RXSTATUS_FRAMING_ERROR)
				flag = TTY_FRAME;
		}	/* end of if (error) */
		tty_insert_flip_char(&info->port, DataByte, flag);
		if (status & RXSTATUS_OVERRUN) {
			/* Overrun is special, since it's
			 * reported immediately, and doesn't
			 * affect the current character
			 */
			work += tty_insert_flip_char(&info->port, 0, TTY_OVERRUN);
		}
	}

	if ( debug_level >= DEBUG_LEVEL_ISR ) {
		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(&info->port);
}

/* mgsl_isr_misc()
 * 
 * 	Service a miscellaneous interrupt source.
 * 	
 * Arguments:		info		pointer to device extension (instance data)
 * Return Value:	None
 */
static void mgsl_isr_misc( struct mgsl_struct *info )
{
	u16 status = usc_InReg( info, MISR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_misc status=%04X\n",
			__FILE__,__LINE__,status);
			
	if ((status & MISCSTATUS_RCC_UNDERRUN) &&
	    (info->params.mode == MGSL_MODE_HDLC)) {

		/* turn off receiver and rx DMA */
		usc_EnableReceiver(info,DISABLE_UNCONDITIONAL);
		usc_DmaCmd(info, DmaCmd_ResetRxChannel);
		usc_UnlatchRxstatusBits(info, RXSTATUS_ALL);
		usc_ClearIrqPendingBits(info, RECEIVE_DATA | RECEIVE_STATUS);
		usc_DisableInterrupts(info, RECEIVE_DATA | RECEIVE_STATUS);

		/* schedule BH handler to restart receiver */
		info->pending_bh |= BH_RECEIVE;
		info->rx_rcc_underrun = true;
	}

	usc_ClearIrqPendingBits( info, MISC );
	usc_UnlatchMiscstatusBits( info, status );

}	/* end of mgsl_isr_misc() */

/* mgsl_isr_null()
 *
 * 	Services undefined interrupt vectors from the
 * 	USC. (hence this function SHOULD never be called)
 * 
 * Arguments:		info		pointer to device extension (instance data)
 * Return Value:	None
 */
static void mgsl_isr_null( struct mgsl_struct *info )
{

}	/* end of mgsl_isr_null() */

/* mgsl_isr_receive_dma()
 * 
 * 	Service a receive DMA channel interrupt.
 * 	For this driver there are two sources of receive DMA interrupts
 * 	as identified in the Receive DMA mode Register (RDMR):
 * 
 * 	BIT3	EOA/EOL		End of List, all receive buffers in receive
 * 				buffer list have been filled (no more free buffers
 * 				available). The DMA controller has shut down.
 * 
 * 	BIT2	EOB		End of Buffer. This interrupt occurs when a receive
 * 				DMA buffer is terminated in response to completion
 * 				of a good frame or a frame with errors. The status
 * 				of the frame is stored in the buffer entry in the
 * 				list of receive buffer entries.
 * 
 * Arguments:		info		pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_receive_dma( struct mgsl_struct *info )
{
	u16 status;
	
	/* clear interrupt pending and IUS bit for Rx DMA IRQ */
	usc_OutDmaReg( info, CDIR, BIT9 | BIT1 );

	/* Read the receive DMA status to identify interrupt type. */
	/* This also clears the status bits. */
	status = usc_InDmaReg( info, RDMR );

	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk("%s(%d):mgsl_isr_receive_dma(%s) status=%04X\n",
			__FILE__,__LINE__,info->device_name,status);
			
	info->pending_bh |= BH_RECEIVE;
	
	if ( status & BIT3 ) {
		info->rx_overflow = true;
		info->icount.buf_overrun++;
	}

}	/* end of mgsl_isr_receive_dma() */

/* mgsl_isr_transmit_dma()
 *
 *	This function services a transmit DMA channel interrupt.
 *
 *	For this driver there is one source of transmit DMA interrupts
 *	as identified in the Transmit DMA Mode Register (TDMR):
 *
 *     	BIT2  EOB       End of Buffer. This interrupt occurs when a
 *     			transmit DMA buffer has been emptied.
 *
 *     	The driver maintains enough transmit DMA buffers to hold at least
 *     	one max frame size transmit frame. When operating in a buffered
 *     	transmit mode, there may be enough transmit DMA buffers to hold at
 *     	least two or more max frame size frames. On an EOB condition,
 *     	determine if there are any queued transmit buffers and copy into
 *     	transmit DMA buffers if we have room.
 *
 * Arguments:		info		pointer to device instance data
 * Return Value:	None
 */
static void mgsl_isr_transmit_dma( struct mgsl_struct *info )
{
	u16 status;

	/* clear interrupt pending and IUS bit for Tx DMA IRQ */
	usc_OutDmaReg(info, CDIR, BIT8 | BIT0 );

	/* Read the transmit DMA status to identify interrupt type. */
	/* This also clears the status bits. */

	status = usc_InDmaReg( info, TDMR );

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

	if ( status & BIT2 ) {
		--info->tx_dma_buffers_used;

		/* if there are transmit frames queued,
		 *  try to load the next one
		 */
		if ( load_next_tx_holding_buffer(info) ) {
			/* if call returns non-zero value, we have
			 * at least one free tx holding buffer
			 */
			info->pending_bh |= BH_TRANSMIT;
		}
	}

}	/* end of mgsl_isr_transmit_dma() */

/* mgsl_interrupt()
 * 
 * 	Interrupt service routine entry point.
 * 	
 * Arguments:
 * 
 * 	irq		interrupt number that caused interrupt
 * 	dev_id		device ID supplied during interrupt registration
 * 	
 * Return Value: None
 */
static irqreturn_t mgsl_interrupt(int dummy, void *dev_id)
{
	struct mgsl_struct *info = dev_id;
	u16 UscVector;
	u16 DmaVector;

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

	spin_lock(&info->irq_spinlock);

	for(;;) {
		/* Read the interrupt vectors from hardware. */
		UscVector = usc_InReg(info, IVR) >> 9;
		DmaVector = usc_InDmaReg(info, DIVR);
		
		if ( debug_level >= DEBUG_LEVEL_ISR )	
			printk("%s(%d):%s UscVector=%08X DmaVector=%08X\n",
				__FILE__,__LINE__,info->device_name,UscVector,DmaVector);
			
		if ( !UscVector && !DmaVector )
			break;
			
		/* Dispatch interrupt vector */
		if ( UscVector )
			(*UscIsrTable[UscVector])(info);
		else if ( (DmaVector&(BIT10|BIT9)) == BIT10)
			mgsl_isr_transmit_dma(info);
		else
			mgsl_isr_receive_dma(info);

		if ( info->isr_overflow ) {
			printk(KERN_ERR "%s(%d):%s isr overflow irq=%d\n",
				__FILE__, __LINE__, info->device_name, info->irq_level);
			usc_DisableMasterIrqBit(info);
			usc_DisableDmaInterrupts(info,DICR_MASTER);
			break;
		}
	}
	
	/* 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->irq_spinlock);
	
	if ( debug_level >= DEBUG_LEVEL_ISR )	
		printk(KERN_DEBUG "%s(%d):mgsl_interrupt(%d)exit.\n",
			__FILE__, __LINE__, info->irq_level);

	return IRQ_HANDLED;
}	/* end of mgsl_interrupt() */

/* startup()
 * 
 * 	Initialize and start device.
 * 	
 * Arguments:		info	pointer to device instance data
 * Return Value:	0 if success, otherwise error code
 */
static int startup(struct mgsl_struct * info)
{
	int retval = 0;

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

	if (tty_port_initialized(&info->port))
		return 0;

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

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

	setup_timer(&info->tx_timer, mgsl_tx_timeout, (unsigned long)info);
	
	/* Allocate and claim adapter resources */
	retval = mgsl_claim_resources(info);
	
	/* perform existence check and diagnostics */
	if ( !retval )
		retval = mgsl_adapter_test(info);
		
	if ( retval ) {
  		if (capable(CAP_SYS_ADMIN) && info->port.tty)
			set_bit(TTY_IO_ERROR, &info->port.tty->flags);
		mgsl_release_resources(info);
  		return retval;
  	}

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

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

	tty_port_set_initialized(&info->port, 1);

	return 0;
}	/* end of startup() */

/* shutdown()
 *
 * Called by mgsl_close() and mgsl_hangup() to shutdown hardware
 *
 * Arguments:		info	pointer to device instance data
 * Return Value:	None
 */
static void shutdown(struct mgsl_struct * info)
{
	unsigned long flags;

	if (!tty_port_initialized(&info->port))
		return;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_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->xmit_buf) {
		free_page((unsigned long) info->xmit_buf);
		info->xmit_buf = NULL;
	}

	spin_lock_irqsave(&info->irq_spinlock,flags);
	usc_DisableMasterIrqBit(info);
	usc_stop_receiver(info);
	usc_stop_transmitter(info);
	usc_DisableInterrupts(info,RECEIVE_DATA | RECEIVE_STATUS |
		TRANSMIT_DATA | TRANSMIT_STATUS | IO_PIN | MISC );
	usc_DisableDmaInterrupts(info,DICR_MASTER + DICR_TRANSMIT + DICR_RECEIVE);

	/* Disable DMAEN (Port 7, Bit 14) */
	/* This disconnects the DMA request signal from the ISA bus */
	/* on the ISA adapter. This has no effect for the PCI adapter */
	usc_OutReg(info, PCR, (u16)((usc_InReg(info, PCR) | BIT15) | BIT14));

	/* Disable INTEN (Port 6, Bit12) */
	/* This disconnects the IRQ request signal to the ISA bus */
	/* on the ISA adapter. This has no effect for the PCI adapter */
	usc_OutReg(info, PCR, (u16)((usc_InReg(info, PCR) | BIT13) | BIT12));

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

	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	mgsl_release_resources(info);

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

	tty_port_set_initialized(&info->port, 0);
}	/* end of shutdown() */

static void mgsl_program_hw(struct mgsl_struct *info)
{
	unsigned long flags;

	spin_lock_irqsave(&info->irq_spinlock,flags);
	
	usc_stop_receiver(info);
	usc_stop_transmitter(info);
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	
	if (info->params.mode == MGSL_MODE_HDLC ||
	    info->params.mode == MGSL_MODE_RAW ||
	    info->netcount)
		usc_set_sync_mode(info);
	else
		usc_set_async_mode(info);
		
	usc_set_serial_signals(info);
	
	info->dcd_chkcount = 0;
	info->cts_chkcount = 0;
	info->ri_chkcount = 0;
	info->dsr_chkcount = 0;

	usc_EnableStatusIrqs(info,SICR_CTS+SICR_DSR+SICR_DCD+SICR_RI);
	usc_EnableInterrupts(info, IO_PIN);
	usc_get_serial_signals(info);
		
	if (info->netcount || info->port.tty->termios.c_cflag & CREAD)
		usc_start_receiver(info);
		
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
}

/* Reconfigure adapter based on new parameters
 */
static void mgsl_change_params(struct mgsl_struct *info)
{
	unsigned cflag;
	int bits_per_char;

	if (!info->port.tty)
		return;
		
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_change_params(%s)\n",
			 __FILE__,__LINE__, info->device_name );
			 
	cflag = info->port.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;
	      /* 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 */

	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 = RXSTATUS_OVERRUN;
	if (I_INPCK(info->port.tty))
		info->read_status_mask |= RXSTATUS_PARITY_ERROR | RXSTATUS_FRAMING_ERROR;
 	if (I_BRKINT(info->port.tty) || I_PARMRK(info->port.tty))
 		info->read_status_mask |= RXSTATUS_BREAK_RECEIVED;
	
	if (I_IGNPAR(info->port.tty))
		info->ignore_status_mask |= RXSTATUS_PARITY_ERROR | RXSTATUS_FRAMING_ERROR;
	if (I_IGNBRK(info->port.tty)) {
		info->ignore_status_mask |= RXSTATUS_BREAK_RECEIVED;
		/* If ignoring parity and break indicators, ignore 
		 * overruns too.  (For real raw support).
		 */
		if (I_IGNPAR(info->port.tty))
			info->ignore_status_mask |= RXSTATUS_OVERRUN;
	}

	mgsl_program_hw(info);

}	/* end of mgsl_change_params() */

/* mgsl_put_char()
 * 
 * 	Add a character to the transmit buffer.
 * 	
 * Arguments:		tty	pointer to tty information structure
 * 			ch	character to add to transmit buffer
 * 		
 * Return Value:	None
 */
static int mgsl_put_char(struct tty_struct *tty, unsigned char ch)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	int ret = 0;

	if (debug_level >= DEBUG_LEVEL_INFO) {
		printk(KERN_DEBUG "%s(%d):mgsl_put_char(%d) on %s\n",
			__FILE__, __LINE__, ch, info->device_name);
	}		
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_put_char"))
		return 0;

	if (!info->xmit_buf)
		return 0;

	spin_lock_irqsave(&info->irq_spinlock, flags);
	
	if ((info->params.mode == MGSL_MODE_ASYNC ) || !info->tx_active) {
		if (info->xmit_cnt < SERIAL_XMIT_SIZE - 1) {
			info->xmit_buf[info->xmit_head++] = ch;
			info->xmit_head &= SERIAL_XMIT_SIZE-1;
			info->xmit_cnt++;
			ret = 1;
		}
	}
	spin_unlock_irqrestore(&info->irq_spinlock, flags);
	return ret;
	
}	/* end of mgsl_put_char() */

/* mgsl_flush_chars()
 * 
 * 	Enable transmitter so remaining characters in the
 * 	transmit buffer are sent.
 * 	
 * Arguments:		tty	pointer to tty information structure
 * Return Value:	None
 */
static void mgsl_flush_chars(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
				
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_flush_chars() entry on %s xmit_cnt=%d\n",
			__FILE__,__LINE__,info->device_name,info->xmit_cnt);
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_flush_chars"))
		return;

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

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

	spin_lock_irqsave(&info->irq_spinlock,flags);
	
	if (!info->tx_active) {
		if ( (info->params.mode == MGSL_MODE_HDLC ||
			info->params.mode == MGSL_MODE_RAW) && info->xmit_cnt ) {
			/* operating in synchronous (frame oriented) mode */
			/* copy data from circular xmit_buf to */
			/* transmit DMA buffer. */
			mgsl_load_tx_dma_buffer(info,
				 info->xmit_buf,info->xmit_cnt);
		}
	 	usc_start_transmitter(info);
	}
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
}	/* end of mgsl_flush_chars() */

/* mgsl_write()
 * 
 * 	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 mgsl_write(struct tty_struct * tty,
		    const unsigned char *buf, int count)
{
	int	c, ret = 0;
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_write(%s) count=%d\n",
			__FILE__,__LINE__,info->device_name,count);
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_write"))
		goto cleanup;

	if (!info->xmit_buf)
		goto cleanup;

	if ( info->params.mode == MGSL_MODE_HDLC ||
			info->params.mode == MGSL_MODE_RAW ) {
		/* operating in synchronous (frame oriented) mode */
		if (info->tx_active) {

			if ( info->params.mode == MGSL_MODE_HDLC ) {
				ret = 0;
				goto cleanup;
			}
			/* transmitter is actively sending data -
			 * if we have multiple transmit dma and
			 * holding buffers, attempt to queue this
			 * frame for transmission at a later time.
			 */
			if (info->tx_holding_count >= info->num_tx_holding_buffers ) {
				/* no tx holding buffers available */
				ret = 0;
				goto cleanup;
			}

			/* queue transmit frame request */
			ret = count;
			save_tx_buffer_request(info,buf,count);

			/* if we have sufficient tx dma buffers,
			 * load the next buffered tx request
			 */
			spin_lock_irqsave(&info->irq_spinlock,flags);
			load_next_tx_holding_buffer(info);
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
			goto cleanup;
		}
	
		/* if operating in HDLC LoopMode and the adapter  */
		/* has yet to be inserted into the loop, we can't */
		/* transmit					  */

		if ( (info->params.flags & HDLC_FLAG_HDLC_LOOPMODE) &&
			!usc_loopmode_active(info) )
		{
			ret = 0;
			goto cleanup;
		}

		if ( info->xmit_cnt ) {
			/* Send accumulated from send_char() calls */
			/* as frame and wait before accepting more data. */
			ret = 0;
			
			/* copy data from circular xmit_buf to */
			/* transmit DMA buffer. */
			mgsl_load_tx_dma_buffer(info,
				info->xmit_buf,info->xmit_cnt);
			if ( debug_level >= DEBUG_LEVEL_INFO )
				printk( "%s(%d):mgsl_write(%s) sync xmit_cnt flushing\n",
					__FILE__,__LINE__,info->device_name);
		} else {
			if ( debug_level >= DEBUG_LEVEL_INFO )
				printk( "%s(%d):mgsl_write(%s) sync transmit accepted\n",
					__FILE__,__LINE__,info->device_name);
			ret = count;
			info->xmit_cnt = count;
			mgsl_load_tx_dma_buffer(info,buf,count);
		}
	} else {
		while (1) {
			spin_lock_irqsave(&info->irq_spinlock,flags);
			c = min_t(int, count,
				min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
				    SERIAL_XMIT_SIZE - info->xmit_head));
			if (c <= 0) {
				spin_unlock_irqrestore(&info->irq_spinlock,flags);
				break;
			}
			memcpy(info->xmit_buf + info->xmit_head, buf, c);
			info->xmit_head = ((info->xmit_head + c) &
					   (SERIAL_XMIT_SIZE-1));
			info->xmit_cnt += c;
			spin_unlock_irqrestore(&info->irq_spinlock,flags);
			buf += c;
			count -= c;
			ret += c;
		}
	}	
	
 	if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped) {
		spin_lock_irqsave(&info->irq_spinlock,flags);
		if (!info->tx_active)
		 	usc_start_transmitter(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
 	}
cleanup:	
	if ( debug_level >= DEBUG_LEVEL_INFO )
		printk( "%s(%d):mgsl_write(%s) returning=%d\n",
			__FILE__,__LINE__,info->device_name,ret);
			
	return ret;
	
}	/* end of mgsl_write() */

/* mgsl_write_room()
 *
 *	Return the count of free bytes in transmit buffer
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static int mgsl_write_room(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	int	ret;
				
	if (mgsl_paranoia_check(info, tty->name, "mgsl_write_room"))
		return 0;
	ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
	if (ret < 0)
		ret = 0;
		
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_write_room(%s)=%d\n",
			 __FILE__,__LINE__, info->device_name,ret );
			 
	if ( info->params.mode == MGSL_MODE_HDLC ||
		info->params.mode == MGSL_MODE_RAW ) {
		/* operating in synchronous (frame oriented) mode */
		if ( info->tx_active )
			return 0;
		else
			return HDLC_MAX_FRAME_SIZE;
	}
	
	return ret;
	
}	/* end of mgsl_write_room() */

/* mgsl_chars_in_buffer()
 *
 *	Return the count of bytes in transmit buffer
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static int mgsl_chars_in_buffer(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
			 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_chars_in_buffer(%s)\n",
			 __FILE__,__LINE__, info->device_name );
			 
	if (mgsl_paranoia_check(info, tty->name, "mgsl_chars_in_buffer"))
		return 0;
		
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_chars_in_buffer(%s)=%d\n",
			 __FILE__,__LINE__, info->device_name,info->xmit_cnt );
			 
	if ( info->params.mode == MGSL_MODE_HDLC ||
		info->params.mode == MGSL_MODE_RAW ) {
		/* operating in synchronous (frame oriented) mode */
		if ( info->tx_active )
			return info->max_frame_size;
		else
			return 0;
	}
			 
	return info->xmit_cnt;
}	/* end of mgsl_chars_in_buffer() */

/* mgsl_flush_buffer()
 *
 *	Discard all data in the send buffer
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_flush_buffer(struct tty_struct *tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_flush_buffer(%s) entry\n",
			 __FILE__,__LINE__, info->device_name );
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_flush_buffer"))
		return;
		
	spin_lock_irqsave(&info->irq_spinlock,flags); 
	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
	del_timer(&info->tx_timer);	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
	tty_wakeup(tty);
}

/* mgsl_send_xchar()
 *
 *	Send a high-priority XON/XOFF character
 * 	
 * Arguments:		tty	pointer to tty info structure
 *			ch	character to send
 * Return Value:	None
 */
static void mgsl_send_xchar(struct tty_struct *tty, char ch)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;

	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_send_xchar(%s,%d)\n",
			 __FILE__,__LINE__, info->device_name, ch );
			 
	if (mgsl_paranoia_check(info, tty->name, "mgsl_send_xchar"))
		return;

	info->x_char = ch;
	if (ch) {
		/* Make sure transmit interrupts are on */
		spin_lock_irqsave(&info->irq_spinlock,flags);
		if (!info->tx_enabled)
		 	usc_start_transmitter(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
}	/* end of mgsl_send_xchar() */

/* mgsl_throttle()
 * 
 * 	Signal remote device to throttle send data (our receive data)
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_throttle(struct tty_struct * tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_throttle(%s) entry\n",
			 __FILE__,__LINE__, info->device_name );

	if (mgsl_paranoia_check(info, tty->name, "mgsl_throttle"))
		return;
	
	if (I_IXOFF(tty))
		mgsl_send_xchar(tty, STOP_CHAR(tty));

	if (C_CRTSCTS(tty)) {
		spin_lock_irqsave(&info->irq_spinlock,flags);
		info->serial_signals &= ~SerialSignal_RTS;
	 	usc_set_serial_signals(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
}	/* end of mgsl_throttle() */

/* mgsl_unthrottle()
 * 
 * 	Signal remote device to stop throttling send data (our receive data)
 * 	
 * Arguments:		tty	pointer to tty info structure
 * Return Value:	None
 */
static void mgsl_unthrottle(struct tty_struct * tty)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_unthrottle(%s) entry\n",
			 __FILE__,__LINE__, info->device_name );

	if (mgsl_paranoia_check(info, tty->name, "mgsl_unthrottle"))
		return;
	
	if (I_IXOFF(tty)) {
		if (info->x_char)
			info->x_char = 0;
		else
			mgsl_send_xchar(tty, START_CHAR(tty));
	}

	if (C_CRTSCTS(tty)) {
		spin_lock_irqsave(&info->irq_spinlock,flags);
		info->serial_signals |= SerialSignal_RTS;
	 	usc_set_serial_signals(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
	
}	/* end of mgsl_unthrottle() */

/* mgsl_get_stats()
 * 
 * 	get the current serial parameters information
 *
 * Arguments:	info		pointer to device instance data
 * 		user_icount	pointer to buffer to hold returned stats
 * 	
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_get_stats(struct mgsl_struct * info, struct mgsl_icount __user *user_icount)
{
	int err;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_get_params(%s)\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;
	
}	/* end of mgsl_get_stats() */

/* mgsl_get_params()
 * 
 * 	get the current serial parameters information
 *
 * Arguments:	info		pointer to device instance data
 * 		user_params	pointer to buffer to hold returned params
 * 	
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_get_params(struct mgsl_struct * info, MGSL_PARAMS __user *user_params)
{
	int err;
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_get_params(%s)\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):mgsl_get_params(%s) user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}
	
	return 0;
	
}	/* end of mgsl_get_params() */

/* mgsl_set_params()
 * 
 * 	set the serial parameters
 * 	
 * Arguments:
 * 
 * 	info		pointer to device instance data
 * 	new_params	user buffer containing new serial params
 *
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_set_params(struct mgsl_struct * info, MGSL_PARAMS __user *new_params)
{
 	unsigned long flags;
	MGSL_PARAMS tmp_params;
	int err;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_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):mgsl_set_params(%s) user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}
	
	mutex_lock(&info->port.mutex);
	spin_lock_irqsave(&info->irq_spinlock,flags);
	memcpy(&info->params,&tmp_params,sizeof(MGSL_PARAMS));
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	
 	mgsl_change_params(info);
	mutex_unlock(&info->port.mutex);
	
	return 0;
	
}	/* end of mgsl_set_params() */

/* mgsl_get_txidle()
 * 
 * 	get the current transmit idle mode
 *
 * Arguments:	info		pointer to device instance data
 * 		idle_mode	pointer to buffer to hold returned idle mode
 * 	
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_get_txidle(struct mgsl_struct * info, int __user *idle_mode)
{
	int err;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_get_txidle(%s)=%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):mgsl_get_txidle(%s) user buffer copy failed\n",
				__FILE__,__LINE__,info->device_name);
		return -EFAULT;
	}
	
	return 0;
	
}	/* end of mgsl_get_txidle() */

/* mgsl_set_txidle()	service ioctl to set transmit idle mode
 * 	
 * Arguments:	 	info		pointer to device instance data
 * 			idle_mode	new idle mode
 *
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_set_txidle(struct mgsl_struct * info, int idle_mode)
{
 	unsigned long flags;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_set_txidle(%s,%d)\n", __FILE__,__LINE__,
			info->device_name, idle_mode );
			
	spin_lock_irqsave(&info->irq_spinlock,flags);
	info->idle_mode = idle_mode;
	usc_set_txidle( info );
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_set_txidle() */

/* mgsl_txenable()
 * 
 * 	enable or disable the transmitter
 * 	
 * Arguments:
 * 
 * 	info		pointer to device instance data
 * 	enable		1 = enable, 0 = disable
 *
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_txenable(struct mgsl_struct * info, int enable)
{
 	unsigned long flags;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_txenable(%s,%d)\n", __FILE__,__LINE__,
			info->device_name, enable);
			
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if ( enable ) {
		if ( !info->tx_enabled ) {

			usc_start_transmitter(info);
			/*--------------------------------------------------
			 * if HDLC/SDLC Loop mode, attempt to insert the
			 * station in the 'loop' by setting CMR:13. Upon
			 * receipt of the next GoAhead (RxAbort) sequence,
			 * the OnLoop indicator (CCSR:7) should go active
			 * to indicate that we are on the loop
			 *--------------------------------------------------*/
			if ( info->params.flags & HDLC_FLAG_HDLC_LOOPMODE )
				usc_loopmode_insert_request( info );
		}
	} else {
		if ( info->tx_enabled )
			usc_stop_transmitter(info);
	}
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_txenable() */

/* mgsl_txabort()	abort send HDLC frame
 * 	
 * Arguments:	 	info		pointer to device instance data
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_txabort(struct mgsl_struct * info)
{
 	unsigned long flags;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_txabort(%s)\n", __FILE__,__LINE__,
			info->device_name);
			
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if ( info->tx_active && info->params.mode == MGSL_MODE_HDLC )
	{
		if ( info->params.flags & HDLC_FLAG_HDLC_LOOPMODE )
			usc_loopmode_cancel_transmit( info );
		else
			usc_TCmd(info,TCmd_SendAbort);
	}
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_txabort() */

/* mgsl_rxenable() 	enable or disable the receiver
 * 	
 * Arguments:	 	info		pointer to device instance data
 * 			enable		1 = enable, 0 = disable
 * Return Value:	0 if success, otherwise error code
 */
static int mgsl_rxenable(struct mgsl_struct * info, int enable)
{
 	unsigned long flags;
 
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_rxenable(%s,%d)\n", __FILE__,__LINE__,
			info->device_name, enable);
			
	spin_lock_irqsave(&info->irq_spinlock,flags);
	if ( enable ) {
		if ( !info->rx_enabled )
			usc_start_receiver(info);
	} else {
		if ( info->rx_enabled )
			usc_stop_receiver(info);
	}
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_rxenable() */

/* mgsl_wait_event() 	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 mgsl_wait_event(struct mgsl_struct * 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):mgsl_wait_event(%s,%d)\n", __FILE__,__LINE__,
			info->device_name, mask);

	spin_lock_irqsave(&info->irq_spinlock,flags);

	/* return immediately if state matches requested events */
	usc_get_serial_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->irq_spinlock,flags);
		goto exit;
	}

	/* save current irq counts */
	cprev = info->icount;
	oldsigs = info->input_signal_events;
	
	/* enable hunt and idle irqs if needed */
	if (mask & (MgslEvent_ExitHuntMode + MgslEvent_IdleReceived)) {
		u16 oldreg = usc_InReg(info,RICR);
		u16 newreg = oldreg +
			 (mask & MgslEvent_ExitHuntMode ? RXSTATUS_EXITED_HUNT:0) +
			 (mask & MgslEvent_IdleReceived ? RXSTATUS_IDLE_RECEIVED:0);
		if (oldreg != newreg)
			usc_OutReg(info, RICR, newreg);
	}
	
	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&info->event_wait_q, &wait);
	
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	

	for(;;) {
		schedule();
		if (signal_pending(current)) {
			rc = -ERESTARTSYS;
			break;
		}
			
		/* get current irq counts */
		spin_lock_irqsave(&info->irq_spinlock,flags);
		cnow = info->icount;
		newsigs = info->input_signal_events;
		set_current_state(TASK_INTERRUPTIBLE);
		spin_unlock_irqrestore(&info->irq_spinlock,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 + MgslEvent_IdleReceived)) {
		spin_lock_irqsave(&info->irq_spinlock,flags);
		if (!waitqueue_active(&info->event_wait_q)) {
			/* disable enable exit hunt mode/idle rcvd IRQs */
			usc_OutReg(info, RICR, usc_InReg(info,RICR) &
				~(RXSTATUS_EXITED_HUNT | RXSTATUS_IDLE_RECEIVED));
		}
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}
exit:
	if ( rc == 0 )
		PUT_USER(rc, events, mask_ptr);
		
	return rc;
	
}	/* end of mgsl_wait_event() */

static int modem_input_wait(struct mgsl_struct *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->irq_spinlock,flags);
	cprev = info->icount;
	add_wait_queue(&info->status_event_wait_q, &wait);
	set_current_state(TASK_INTERRUPTIBLE);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

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

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

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

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

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

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

	spin_lock_irqsave(&info->irq_spinlock,flags);
 	usc_get_serial_signals(info);
	spin_unlock_irqrestore(&info->irq_spinlock,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)
{
	struct mgsl_struct *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->irq_spinlock,flags);
 	usc_set_serial_signals(info);
	spin_unlock_irqrestore(&info->irq_spinlock,flags);

	return 0;
}

/* mgsl_break()		Set or clear transmit break condition
 *
 * Arguments:		tty		pointer to tty instance data
 *			break_state	-1=set break condition, 0=clear
 * Return Value:	error code
 */
static int mgsl_break(struct tty_struct *tty, int break_state)
{
	struct mgsl_struct * info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_break(%s,%d)\n",
			 __FILE__,__LINE__, info->device_name, break_state);
			 
	if (mgsl_paranoia_check(info, tty->name, "mgsl_break"))
		return -EINVAL;

	spin_lock_irqsave(&info->irq_spinlock,flags);
 	if (break_state == -1)
		usc_OutReg(info,IOCR,(u16)(usc_InReg(info,IOCR) | BIT7));
	else 
		usc_OutReg(info,IOCR,(u16)(usc_InReg(info,IOCR) & ~BIT7));
	spin_unlock_irqrestore(&info->irq_spinlock,flags);
	return 0;
	
}	/* end of mgsl_break() */

/*
 * 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.
 */
static int msgl_get_icount(struct tty_struct *tty,
				struct serial_icounter_struct *icount)

{
	struct mgsl_struct * info = tty->driver_data;
	struct mgsl_icount cnow;	/* kernel counter temps */
	unsigned long flags;

	spin_lock_irqsave(&info->irq_spinlock,flags);
	cnow = info->icount;
	spin_unlock_irqrestore(&info->irq_spinlock,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;
}

/* mgsl_ioctl()	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 mgsl_ioctl(struct tty_struct *tty,
		    unsigned int cmd, unsigned long arg)
{
	struct mgsl_struct * info = tty->driver_data;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_ioctl %s cmd=%08X\n", __FILE__,__LINE__,
			info->device_name, cmd );
	
	if (mgsl_paranoia_check(info, tty->name, "mgsl_ioctl"))
		return -ENODEV;

	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
	    (cmd != TIOCMIWAIT)) {
		if (tty_io_error(tty))
		    return -EIO;
	}

	return mgsl_ioctl_common(info, cmd, arg);
}

static int mgsl_ioctl_common(struct mgsl_struct *info, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	
	switch (cmd) {
		case MGSL_IOCGPARAMS:
			return mgsl_get_params(info, argp);
		case MGSL_IOCSPARAMS:
			return mgsl_set_params(info, argp);
		case MGSL_IOCGTXIDLE:
			return mgsl_get_txidle(info, argp);
		case MGSL_IOCSTXIDLE:
			return mgsl_set_txidle(info,(int)arg);
		case MGSL_IOCTXENABLE:
			return mgsl_txenable(info,(int)arg);
		case MGSL_IOCRXENABLE:
			return mgsl_rxenable(info,(int)arg);
		case MGSL_IOCTXABORT:
			return mgsl_txabort(info);
		case MGSL_IOCGSTATS:
			return mgsl_get_stats(info, argp);
		case MGSL_IOCWAITEVENT:
			return mgsl_wait_event(info, argp);
		case MGSL_IOCLOOPTXDONE:
			return mgsl_loopmode_send_done(info);
		/* 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);

		default:
			return -ENOIOCTLCMD;
	}
	return 0;
}

/* mgsl_set_termios()
 * 
 * 	Set new termios settings
 * 	
 * Arguments:
 * 
 * 	tty		pointer to tty structure
 * 	termios		pointer to buffer to hold returned old termios
 * 	
 * Return Value:		None
 */
static void mgsl_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
	struct mgsl_struct *info = tty->driver_data;
	unsigned long flags;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_set_termios %s\n", __FILE__,__LINE__,
			tty->driver->name );
	
	mgsl_change_params(info);

	/* 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->irq_spinlock,flags);
	 	usc_set_serial_signals(info);
		spin_unlock_irqrestore(&info->irq_spinlock,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->irq_spinlock,flags);
	 	usc_set_serial_signals(info);
		spin_unlock_irqrestore(&info->irq_spinlock,flags);
	}

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

}	/* end of mgsl_set_termios() */

/* mgsl_close()
 * 
 * 	Called when port is closed. Wait for remaining data to be
 * 	sent. Disable port and free resources.
 * 	
 * Arguments:
 * 
 * 	tty	pointer to open tty structure
 * 	filp	pointer to open file object
 * 	
 * Return Value:	None
 */
static void mgsl_close(struct tty_struct *tty, struct file * filp)
{
	struct mgsl_struct * info = tty->driver_data;

	if (mgsl_paranoia_check(info, tty->name, "mgsl_close"))
		return;
	
	if (debug_level >= DEBUG_LEVEL_INFO)
		printk("%s(%d):mgsl_close(%s) 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 (tty_port_initialized(&info->port))
 		mgsl_wait_until_sent(tty, info->timeout);
	mgsl_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):mgsl_close(%s) exit, count=%d\n", __FILE__,__LINE__,
			tty->driver->name, info->port.count);
			
}	/* end of mgsl_close() */

/* mgsl_wait_until_sent()
 *
 *	Wait until the transmitter is empty.
 *
 * Arguments:
 *
 *	tty		pointer to tty info structure
 *	timeout		time to wait for send completion
 *
 * Return Value:	None
 */
static void mgsl_wait_until_sent(struct tty_struct *tty, int timeout)
{
	struct mgsl_struct * info = tty->driver_data;