[PATCH] new driver synclink_gt

New character device driver for the SyncLink GT and SyncLink AC families of
synchronous and asynchronous serial adapters

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 4510 insertions, 0 deletions

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index b1b34edcd70c..dd7e6901c575 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -220,6 +220,14 @@ config SYNCLINKMP
 	  The module will be called synclinkmp.  If you want to do that, say M
 	  here.
 
+config SYNCLINK_GT
+	tristate "SyncLink GT/AC support"
+	depends on SERIAL_NONSTANDARD
+	help
+	  Support for SyncLink GT and SyncLink AC families of
+	  synchronous and asynchronous serial adapters
+	  manufactured by Microgate Systems, Ltd. (www.microgate.com)
+
 config N_HDLC
 	tristate "HDLC line discipline support"
 	depends on SERIAL_NONSTANDARD
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 4aeae687e88a..d973d14d8f7f 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_RISCOM8)		+= riscom8.o
 obj-$(CONFIG_ISI)		+= isicom.o
 obj-$(CONFIG_SYNCLINK)		+= synclink.o
 obj-$(CONFIG_SYNCLINKMP)	+= synclinkmp.o
+obj-$(CONFIG_SYNCLINK_GT)	+= synclink_gt.o
 obj-$(CONFIG_N_HDLC)		+= n_hdlc.o
 obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o
 obj-$(CONFIG_SX)		+= sx.o generic_serial.o
diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
new file mode 100644
index 000000000000..2b9cde94e2f7
--- /dev/null
+++ b/drivers/char/synclink_gt.c
@@ -0,0 +1,4501 @@
+/*
+ * $Id: synclink_gt.c,v 4.20 2005/11/08 19:51:55 paulkf Exp $
+ *
+ * Device driver for Microgate SyncLink GT serial adapters.
+ *
+ * written by Paul Fulghum for Microgate Corporation
+ * paulkf@microgate.com
+ *
+ * Microgate and SyncLink are trademarks of Microgate Corporation
+ *
+ * This code is released under the GNU General Public License (GPL)
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * DEBUG OUTPUT DEFINITIONS
+ *
+ * uncomment lines below to enable specific types of debug output
+ *
+ * DBGINFO   information - most verbose output
+ * DBGERR    serious errors
+ * DBGBH     bottom half service routine debugging
+ * DBGISR    interrupt service routine debugging
+ * DBGDATA   output receive and transmit data
+ * DBGTBUF   output transmit DMA buffers and registers
+ * DBGRBUF   output receive DMA buffers and registers
+ */
+
+#define DBGINFO(fmt) if (debug_level >= DEBUG_LEVEL_INFO) printk fmt
+#define DBGERR(fmt) if (debug_level >= DEBUG_LEVEL_ERROR) printk fmt
+#define DBGBH(fmt) if (debug_level >= DEBUG_LEVEL_BH) printk fmt
+#define DBGISR(fmt) if (debug_level >= DEBUG_LEVEL_ISR) printk fmt
+#define DBGDATA(info, buf, size, label) if (debug_level >= DEBUG_LEVEL_DATA) trace_block((info), (buf), (size), (label))
+//#define DBGTBUF(info) dump_tbufs(info)
+//#define DBGRBUF(info) dump_rbufs(info)
+
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/version.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/slab.h>
+#include <linux/netdevice.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/ioctl.h>
+#include <linux/termios.h>
+#include <linux/bitops.h>
+#include <linux/workqueue.h>
+#include <linux/hdlc.h>
+
+#include <asm/serial.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/dma.h>
+#include <asm/types.h>
+#include <asm/uaccess.h>
+
+#include "linux/synclink.h"
+
+#ifdef CONFIG_HDLC_MODULE
+#define CONFIG_HDLC 1
+#endif
+
+/*
+ * module identification
+ */
+static char *driver_name     = "SyncLink GT";
+static char *driver_version  = "$Revision: 4.20 $";
+static char *tty_driver_name = "synclink_gt";
+static char *tty_dev_prefix  = "ttySLG";
+MODULE_LICENSE("GPL");
+#define MGSL_MAGIC 0x5401
+#define MAX_DEVICES 12
+
+static struct pci_device_id pci_table[] = {
+	{PCI_VENDOR_ID_MICROGATE, SYNCLINK_GT_DEVICE_ID, PCI_ANY_ID, PCI_ANY_ID,},
+	{PCI_VENDOR_ID_MICROGATE, SYNCLINK_GT4_DEVICE_ID, PCI_ANY_ID, PCI_ANY_ID,},
+	{PCI_VENDOR_ID_MICROGATE, SYNCLINK_AC_DEVICE_ID, PCI_ANY_ID, PCI_ANY_ID,},
+	{0,}, /* terminate list */
+};
+MODULE_DEVICE_TABLE(pci, pci_table);
+
+static int  init_one(struct pci_dev *dev,const struct pci_device_id *ent);
+static void remove_one(struct pci_dev *dev);
+static struct pci_driver pci_driver = {
+	.name		= "synclink_gt",
+	.id_table	= pci_table,
+	.probe		= init_one,
+	.remove		= __devexit_p(remove_one),
+};
+
+static int pci_registered;
+
+/*
+ * module configuration and status
+ */
+static struct slgt_info *slgt_device_list;
+static int slgt_device_count;
+
+static int ttymajor;
+static int debug_level;
+static int maxframe[MAX_DEVICES];
+static int dosyncppp[MAX_DEVICES];
+
+module_param(ttymajor, int, 0);
+module_param(debug_level, int, 0);
+module_param_array(maxframe, int, NULL, 0);
+module_param_array(dosyncppp, int, NULL, 0);
+
+MODULE_PARM_DESC(ttymajor, "TTY major device number override: 0=auto assigned");
+MODULE_PARM_DESC(debug_level, "Debug syslog output: 0=disabled, 1 to 5=increasing detail");
+MODULE_PARM_DESC(maxframe, "Maximum frame size used by device (4096 to 65535)");
+MODULE_PARM_DESC(dosyncppp, "Enable synchronous net device, 0=disable 1=enable");
+
+/*
+ * tty support and callbacks
+ */
+#define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
+
+static struct tty_driver *serial_driver;
+
+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 termios *old_termios);
+
+static int  write(struct tty_struct *tty, const unsigned char *buf, int count);
+static void 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, struct file *file, unsigned int cmd, unsigned long arg);
+static int  read_proc(char *page, char **start, off_t off, int count,int *eof, void *data);
+static int  chars_in_buffer(struct tty_struct *tty);
+static void throttle(struct tty_struct * tty);
+static void unthrottle(struct tty_struct * tty);
+static void set_break(struct tty_struct *tty, int break_state);
+
+/*
+ * generic HDLC support and callbacks
+ */
+#ifdef CONFIG_HDLC
+#define dev_to_port(D) (dev_to_hdlc(D)->priv)
+static void hdlcdev_tx_done(struct slgt_info *info);
+static void hdlcdev_rx(struct slgt_info *info, char *buf, int size);
+static int  hdlcdev_init(struct slgt_info *info);
+static void hdlcdev_exit(struct slgt_info *info);
+#endif
+
+
+/*
+ * device specific structures, macros and functions
+ */
+
+#define SLGT_MAX_PORTS 4
+#define SLGT_REG_SIZE  256
+
+/*
+ * DMA buffer descriptor and access macros
+ */
+struct slgt_desc
+{
+	unsigned short count;
+	unsigned short status;
+	unsigned int pbuf;  /* physical address of data buffer */
+	unsigned int next;  /* physical address of next descriptor */
+
+	/* driver book keeping */
+	char *buf;          /* virtual  address of data buffer */
+    	unsigned int pdesc; /* physical address of this descriptor */
+	dma_addr_t buf_dma_addr;
+};
+
+#define set_desc_buffer(a,b) (a).pbuf = cpu_to_le32((unsigned int)(b))
+#define set_desc_next(a,b) (a).next   = cpu_to_le32((unsigned int)(b))
+#define set_desc_count(a,b)(a).count  = cpu_to_le16((unsigned short)(b))
+#define set_desc_eof(a,b)  (a).status = cpu_to_le16((b) ? (le16_to_cpu((a).status) | BIT0) : (le16_to_cpu((a).status) & ~BIT0))
+#define desc_count(a)      (le16_to_cpu((a).count))
+#define desc_status(a)     (le16_to_cpu((a).status))
+#define desc_complete(a)   (le16_to_cpu((a).status) & BIT15)
+#define desc_eof(a)        (le16_to_cpu((a).status) & BIT2)
+#define desc_crc_error(a)  (le16_to_cpu((a).status) & BIT1)
+#define desc_abort(a)      (le16_to_cpu((a).status) & BIT0)
+#define desc_residue(a)    ((le16_to_cpu((a).status) & 0x38) >> 3)
+
+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
+ */
+struct slgt_info {
+	void *if_ptr;		/* General purpose pointer (used by SPPP) */
+
+	struct slgt_info *next_device;	/* device list link */
+
+	int magic;
+	int flags;
+
+	char device_name[25];
+	struct pci_dev *pdev;
+
+	int port_count;  /* count of ports on adapter */
+	int adapter_num; /* adapter instance number */
+	int port_num;    /* port instance number */
+
+	/* array of pointers to port contexts on this adapter */
+	struct slgt_info *port_array[SLGT_MAX_PORTS];
+
+	int			count;		/* count of opens */
+	int			line;		/* tty line instance number */
+	unsigned short		close_delay;
+	unsigned short		closing_wait;	/* time to wait before closing */
+
+	struct mgsl_icount	icount;
+
+	struct tty_struct 	*tty;
+	int			timeout;
+	int			x_char;		/* xon/xoff character */
+	int			blocked_open;	/* # of blocked opens */
+	unsigned int		read_status_mask;
+	unsigned int 		ignore_status_mask;
+
+	wait_queue_head_t	open_wait;
+	wait_queue_head_t	close_wait;
+
+	wait_queue_head_t	status_event_wait_q;
+	wait_queue_head_t	event_wait_q;
+	struct timer_list	tx_timer;
+	struct timer_list	rx_timer;
+
+	spinlock_t lock;	/* spinlock for synchronizing with ISR */
+
+	struct work_struct task;
+	u32 pending_bh;
+	int bh_requested;
+	int bh_running;
+
+	int isr_overflow;
+	int irq_requested;	/* nonzero if IRQ requested */
+	int irq_occurred;	/* for diagnostics use */
+
+	/* device configuration */
+
+	unsigned int bus_type;
+	unsigned int irq_level;
+	unsigned long irq_flags;
+
+	unsigned char __iomem * reg_addr;  /* memory mapped registers address */
+	u32 phys_reg_addr;
+	u32 reg_offset;
+	int reg_addr_requested;
+
+	MGSL_PARAMS params;       /* communications parameters */
+	u32 idle_mode;
+	u32 max_frame_size;       /* as set by device config */
+
+	unsigned int raw_rx_size;
+	unsigned int if_mode;
+
+	/* device status */
+
+	int rx_enabled;
+	int rx_restart;
+
+	int tx_enabled;
+	int tx_active;
+
+	unsigned char signals;    /* serial signal states */
+	unsigned int init_error;  /* initialization error */
+
+	unsigned char *tx_buf;
+	int tx_count;
+
+	char flag_buf[MAX_ASYNC_BUFFER_SIZE];
+	char char_buf[MAX_ASYNC_BUFFER_SIZE];
+	BOOLEAN drop_rts_on_tx_done;
+	struct	_input_signal_events	input_signal_events;
+
+	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 *bufs;		/* virtual address of DMA buffer lists */
+	dma_addr_t bufs_dma_addr; /* physical address of buffer descriptors */
+
+	unsigned int rbuf_count;
+	struct slgt_desc *rbufs;
+	unsigned int rbuf_current;
+	unsigned int rbuf_index;
+
+	unsigned int tbuf_count;
+	struct slgt_desc *tbufs;
+	unsigned int tbuf_current;
+	unsigned int tbuf_start;
+
+	unsigned char *tmp_rbuf;
+	unsigned int tmp_rbuf_count;
+
+	/* SPPP/Cisco HDLC device parts */
+
+	int netcount;
+	int dosyncppp;
+	spinlock_t netlock;
+#ifdef CONFIG_HDLC
+	struct net_device *netdev;
+#endif
+
+};
+
+static MGSL_PARAMS default_params = {
+	.mode            = MGSL_MODE_HDLC,
+	.loopback        = 0,
+	.flags           = HDLC_FLAG_UNDERRUN_ABORT15,
+	.encoding        = HDLC_ENCODING_NRZI_SPACE,
+	.clock_speed     = 0,
+	.addr_filter     = 0xff,
+	.crc_type        = HDLC_CRC_16_CCITT,
+	.preamble_length = HDLC_PREAMBLE_LENGTH_8BITS,
+	.preamble        = HDLC_PREAMBLE_PATTERN_NONE,
+	.data_rate       = 9600,
+	.data_bits       = 8,
+	.stop_bits       = 1,
+	.parity          = ASYNC_PARITY_NONE
+};
+
+
+#define BH_RECEIVE  1
+#define BH_TRANSMIT 2
+#define BH_STATUS   4
+#define IO_PIN_SHUTDOWN_LIMIT 100
+
+#define DMABUFSIZE 256
+#define DESC_LIST_SIZE 4096
+
+#define MASK_PARITY  BIT1
+#define MASK_FRAMING BIT2
+#define MASK_BREAK   BIT3
+#define MASK_OVERRUN BIT4
+
+#define GSR   0x00 /* global status */
+#define TDR   0x80 /* tx data */
+#define RDR   0x80 /* rx data */
+#define TCR   0x82 /* tx control */
+#define TIR   0x84 /* tx idle */
+#define TPR   0x85 /* tx preamble */
+#define RCR   0x86 /* rx control */
+#define VCR   0x88 /* V.24 control */
+#define CCR   0x89 /* clock control */
+#define BDR   0x8a /* baud divisor */
+#define SCR   0x8c /* serial control */
+#define SSR   0x8e /* serial status */
+#define RDCSR 0x90 /* rx DMA control/status */
+#define TDCSR 0x94 /* tx DMA control/status */
+#define RDDAR 0x98 /* rx DMA descriptor address */
+#define TDDAR 0x9c /* tx DMA descriptor address */
+
+#define RXIDLE      BIT14
+#define RXBREAK     BIT14
+#define IRQ_TXDATA  BIT13
+#define IRQ_TXIDLE  BIT12
+#define IRQ_TXUNDER BIT11 /* HDLC */
+#define IRQ_RXDATA  BIT10
+#define IRQ_RXIDLE  BIT9  /* HDLC */
+#define IRQ_RXBREAK BIT9  /* async */
+#define IRQ_RXOVER  BIT8
+#define IRQ_DSR     BIT7
+#define IRQ_CTS     BIT6
+#define IRQ_DCD     BIT5
+#define IRQ_RI      BIT4
+#define IRQ_ALL     0x3ff0
+#define IRQ_MASTER  BIT0
+
+#define slgt_irq_on(info, mask) \
+	wr_reg16((info), SCR, (unsigned short)(rd_reg16((info), SCR) | (mask)))
+#define slgt_irq_off(info, mask) \
+	wr_reg16((info), SCR, (unsigned short)(rd_reg16((info), SCR) & ~(mask)))
+
+static __u8  rd_reg8(struct slgt_info *info, unsigned int addr);
+static void  wr_reg8(struct slgt_info *info, unsigned int addr, __u8 value);
+static __u16 rd_reg16(struct slgt_info *info, unsigned int addr);
+static void  wr_reg16(struct slgt_info *info, unsigned int addr, __u16 value);
+static __u32 rd_reg32(struct slgt_info *info, unsigned int addr);
+static void  wr_reg32(struct slgt_info *info, unsigned int addr, __u32 value);
+
+static void  msc_set_vcr(struct slgt_info *info);
+
+static int  startup(struct slgt_info *info);
+static int  block_til_ready(struct tty_struct *tty, struct file * filp,struct slgt_info *info);
+static void shutdown(struct slgt_info *info);
+static void program_hw(struct slgt_info *info);
+static void change_params(struct slgt_info *info);
+
+static int  register_test(struct slgt_info *info);
+static int  irq_test(struct slgt_info *info);
+static int  loopback_test(struct slgt_info *info);
+static int  adapter_test(struct slgt_info *info);
+
+static void reset_adapter(struct slgt_info *info);
+static void reset_port(struct slgt_info *info);
+static void async_mode(struct slgt_info *info);
+static void hdlc_mode(struct slgt_info *info);
+
+static void rx_stop(struct slgt_info *info);
+static void rx_start(struct slgt_info *info);
+static void reset_rbufs(struct slgt_info *info);
+static void free_rbufs(struct slgt_info *info, unsigned int first, unsigned int last);
+static void rdma_reset(struct slgt_info *info);
+static int  rx_get_frame(struct slgt_info *info);
+static int  rx_get_buf(struct slgt_info *info);
+
+static void tx_start(struct slgt_info *info);
+static void tx_stop(struct slgt_info *info);
+static void tx_set_idle(struct slgt_info *info);
+static unsigned int free_tbuf_count(struct slgt_info *info);
+static void reset_tbufs(struct slgt_info *info);
+static void tdma_reset(struct slgt_info *info);
+static void tx_load(struct slgt_info *info, const char *buf, unsigned int count);
+
+static void get_signals(struct slgt_info *info);
+static void set_signals(struct slgt_info *info);
+static void enable_loopback(struct slgt_info *info);
+static void set_rate(struct slgt_info *info, u32 data_rate);
+
+static int  bh_action(struct slgt_info *info);
+static void bh_handler(void* context);
+static void bh_transmit(struct slgt_info *info);
+static void isr_serial(struct slgt_info *info);
+static void isr_rdma(struct slgt_info *info);
+static void isr_txeom(struct slgt_info *info, unsigned short status);
+static void isr_tdma(struct slgt_info *info);
+static irqreturn_t slgt_interrupt(int irq, void *dev_id, struct pt_regs * regs);
+
+static int  alloc_dma_bufs(struct slgt_info *info);
+static void free_dma_bufs(struct slgt_info *info);
+static int  alloc_desc(struct slgt_info *info);
+static void free_desc(struct slgt_info *info);
+static int  alloc_bufs(struct slgt_info *info, struct slgt_desc *bufs, int count);
+static void free_bufs(struct slgt_info *info, struct slgt_desc *bufs, int count);
+
+static int  alloc_tmp_rbuf(struct slgt_info *info);
+static void free_tmp_rbuf(struct slgt_info *info);
+
+static void tx_timeout(unsigned long context);
+static void rx_timeout(unsigned long context);
+
+/*
+ * ioctl handlers
+ */
+static int  get_stats(struct slgt_info *info, struct mgsl_icount __user *user_icount);
+static int  get_params(struct slgt_info *info, MGSL_PARAMS __user *params);
+static int  set_params(struct slgt_info *info, MGSL_PARAMS __user *params);
+static int  get_txidle(struct slgt_info *info, int __user *idle_mode);
+static int  set_txidle(struct slgt_info *info, int idle_mode);
+static int  tx_enable(struct slgt_info *info, int enable);
+static int  tx_abort(struct slgt_info *info);
+static int  rx_enable(struct slgt_info *info, int enable);
+static int  modem_input_wait(struct slgt_info *info,int arg);
+static int  wait_mgsl_event(struct slgt_info *info, int __user *mask_ptr);
+static int  tiocmget(struct tty_struct *tty, struct file *file);
+static int  tiocmset(struct tty_struct *tty, struct file *file,
+		     unsigned int set, unsigned int clear);
+static void set_break(struct tty_struct *tty, int break_state);
+static int  get_interface(struct slgt_info *info, int __user *if_mode);
+static int  set_interface(struct slgt_info *info, int if_mode);
+
+/*
+ * driver functions
+ */
+static void add_device(struct slgt_info *info);
+static void device_init(int adapter_num, struct pci_dev *pdev);
+static int  claim_resources(struct slgt_info *info);
+static void release_resources(struct slgt_info *info);
+
+/*
+ * DEBUG OUTPUT CODE
+ */
+#ifndef DBGINFO
+#define DBGINFO(fmt)
+#endif
+#ifndef DBGERR
+#define DBGERR(fmt)
+#endif
+#ifndef DBGBH
+#define DBGBH(fmt)
+#endif
+#ifndef DBGISR
+#define DBGISR(fmt)
+#endif
+
+#ifdef DBGDATA
+static void trace_block(struct slgt_info *info, const char *data, int count, const char *label)
+{
+	int i;
+	int linecount;
+	printk("%s %s data:\n",info->device_name, label);
+	while(count) {
+		linecount = (count > 16) ? 16 : count;
+		for(i=0; i < linecount; i++)
+			printk("%02X ",(unsigned char)data[i]);
+		for(;i<17;i++)
+			printk("   ");
+		for(i=0;i<linecount;i++) {
+			if (data[i]>=040 && data[i]<=0176)
+				printk("%c",data[i]);
+			else
+				printk(".");
+		}
+		printk("\n");
+		data  += linecount;
+		count -= linecount;
+	}
+}
+#else
+#define DBGDATA(info, buf, size, label)
+#endif
+
+#ifdef DBGTBUF
+static void dump_tbufs(struct slgt_info *info)
+{
+	int i;
+	printk("tbuf_current=%d\n", info->tbuf_current);
+	for (i=0 ; i < info->tbuf_count ; i++) {
+		printk("%d: count=%04X status=%04X\n",
+			i, le16_to_cpu(info->tbufs[i].count), le16_to_cpu(info->tbufs[i].status));
+	}
+}
+#else
+#define DBGTBUF(info)
+#endif
+
+#ifdef DBGRBUF
+static void dump_rbufs(struct slgt_info *info)
+{
+	int i;
+	printk("rbuf_current=%d\n", info->rbuf_current);
+	for (i=0 ; i < info->rbuf_count ; i++) {
+		printk("%d: count=%04X status=%04X\n",
+			i, le16_to_cpu(info->rbufs[i].count), le16_to_cpu(info->rbufs[i].status));
+	}
+}
+#else
+#define DBGRBUF(info)
+#endif
+
+static inline int sanity_check(struct slgt_info *info, char *devname, const char *name)
+{
+#ifdef SANITY_CHECK
+	if (!info) {
+		printk("null struct slgt_info for (%s) in %s\n", devname, name);
+		return 1;
+	}
+	if (info->magic != MGSL_MAGIC) {
+		printk("bad magic number struct slgt_info (%s) in %s\n", devname, name);
+		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->receive_buf)
+			ld->receive_buf(tty, data, flags, count);
+		tty_ldisc_deref(ld);
+	}
+}
+
+/* tty callbacks */
+
+static int open(struct tty_struct *tty, struct file *filp)
+{
+	struct slgt_info *info;
+	int retval, line;
+	unsigned long flags;
+
+	line = tty->index;
+	if ((line < 0) || (line >= slgt_device_count)) {
+		DBGERR(("%s: open with invalid line #%d.\n", driver_name, line));
+		return -ENODEV;
+	}
+
+	info = slgt_device_list;
+	while(info && info->line != line)
+		info = info->next_device;
+	if (sanity_check(info, tty->name, "open"))
+		return -ENODEV;
+	if (info->init_error) {
+		DBGERR(("%s init error=%d\n", info->device_name, info->init_error));
+		return -ENODEV;
+	}
+
+	tty->driver_data = info;
+	info->tty = tty;
+
+	DBGINFO(("%s open, old ref count = %d\n", info->device_name, info->count));
+
+	/* If port is closing, signal caller to try again */
+	if (tty_hung_up_p(filp) || info->flags & ASYNC_CLOSING){
+		if (info->flags & ASYNC_CLOSING)
+			interruptible_sleep_on(&info->close_wait);
+		retval = ((info->flags & ASYNC_HUP_NOTIFY) ?
+			-EAGAIN : -ERESTARTSYS);
+		goto cleanup;
+	}
+
+	info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
+
+	spin_lock_irqsave(&info->netlock, flags);
+	if (info->netcount) {
+		retval = -EBUSY;
+		spin_unlock_irqrestore(&info->netlock, flags);
+		goto cleanup;
+	}
+	info->count++;
+	spin_unlock_irqrestore(&info->netlock, flags);
+
+	if (info->count == 1) {
+		/* 1st open on this device, init hardware */
+		retval = startup(info);
+		if (retval < 0)
+			goto cleanup;
+	}
+
+	retval = block_til_ready(tty, filp, info);
+	if (retval) {
+		DBGINFO(("%s block_til_ready rc=%d\n", info->device_name, retval));
+		goto cleanup;
+	}
+
+	retval = 0;
+
+cleanup:
+	if (retval) {
+		if (tty->count == 1)
+			info->tty = NULL; /* tty layer will release tty struct */
+		if(info->count)
+			info->count--;
+	}
+
+	DBGINFO(("%s open rc=%d\n", info->device_name, retval));
+	return retval;
+}
+
+static void close(struct tty_struct *tty, struct file *filp)
+{
+	struct slgt_info *info = tty->driver_data;
+
+	if (sanity_check(info, tty->name, "close"))
+		return;
+	DBGINFO(("%s close entry, count=%d\n", info->device_name, info->count));
+
+	if (!info->count)
+		return;
+
+	if (tty_hung_up_p(filp))
+		goto cleanup;
+
+	if ((tty->count == 1) && (info->count != 1)) {
+		/*
+		 * tty->count is 1 and the tty structure will be freed.
+		 * info->count should be one in this case.
+		 * if it's not, correct it so that the port is shutdown.
+		 */
+		DBGERR(("%s close: bad refcount; tty->count=1, "
+		       "info->count=%d\n", info->device_name, info->count));
+		info->count = 1;
+	}
+
+	info->count--;
+
+	/* if at least one open remaining, leave hardware active */
+	if (info->count)
+		goto cleanup;
+
+	info->flags |= ASYNC_CLOSING;
+
+	/* set tty->closing to notify line discipline to
+	 * only process XON/XOFF characters. Only the N_TTY
+	 * discipline appears to use this (ppp does not).
+	 */
+	tty->closing = 1;
+
+	/* wait for transmit data to clear all layers */
+
+	if (info->closing_wait != ASYNC_CLOSING_WAIT_NONE) {
+		DBGINFO(("%s call tty_wait_until_sent\n", info->device_name));
+		tty_wait_until_sent(tty, info->closing_wait);
+	}
+
+ 	if (info->flags & ASYNC_INITIALIZED)
+ 		wait_until_sent(tty, info->timeout);
+	if (tty->driver->flush_buffer)
+		tty->driver->flush_buffer(tty);
+	tty_ldisc_flush(tty);
+
+	shutdown(info);
+
+	tty->closing = 0;
+	info->tty = NULL;
+
+	if (info->blocked_open) {
+		if (info->close_delay) {
+			msleep_interruptible(jiffies_to_msecs(info->close_delay));
+		}
+		wake_up_interruptible(&info->open_wait);
+	}
+
+	info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING);
+
+	wake_up_interruptible(&info->close_wait);
+
+cleanup:
+	DBGINFO(("%s close exit, count=%d\n", tty->driver->name, info->count));
+}
+
+static void hangup(struct tty_struct *tty)
+{
+	struct slgt_info *info = tty->driver_data;
+
+	if (sanity_check(info, tty->name, "hangup"))
+		return;
+	DBGINFO(("%s hangup\n", info->device_name));
+
+	flush_buffer(tty);
+	shutdown(info);
+
+	info->count = 0;
+	info->flags &= ~ASYNC_NORMAL_ACTIVE;
+	info->tty = NULL;
+
+	wake_up_interruptible(&info->open_wait);
+}
+
+static void set_termios(struct tty_struct *tty, struct termios *old_termios)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	DBGINFO(("%s set_termios\n", tty->driver->name));
+
+	/* just return if nothing has changed */
+	if ((tty->termios->c_cflag == old_termios->c_cflag)
+	    && (RELEVANT_IFLAG(tty->termios->c_iflag)
+		== RELEVANT_IFLAG(old_termios->c_iflag)))
+		return;
+
+	change_params(info);
+
+	/* Handle transition to B0 status */
+	if (old_termios->c_cflag & CBAUD &&
+	    !(tty->termios->c_cflag & CBAUD)) {
+		info->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->signals |= SerialSignal_DTR;
+ 		if (!(tty->termios->c_cflag & CRTSCTS) ||
+ 		    !test_bit(TTY_THROTTLED, &tty->flags)) {
+			info->signals |= SerialSignal_RTS;
+ 		}
+		spin_lock_irqsave(&info->lock,flags);
+	 	set_signals(info);
+		spin_unlock_irqrestore(&info->lock,flags);
+	}
+
+	/* Handle turning off CRTSCTS */
+	if (old_termios->c_cflag & CRTSCTS &&
+	    !(tty->termios->c_cflag & CRTSCTS)) {
+		tty->hw_stopped = 0;
+		tx_release(tty);
+	}
+}
+
+static int write(struct tty_struct *tty,
+		 const unsigned char *buf, int count)
+{
+	int ret = 0;
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "write"))
+		goto cleanup;
+	DBGINFO(("%s write count=%d\n", info->device_name, count));
+
+	if (!tty || !info->tx_buf)
+		goto cleanup;
+
+	if (count > info->max_frame_size) {
+		ret = -EIO;
+		goto cleanup;
+	}
+
+	if (!count)
+		goto cleanup;
+
+	if (info->params.mode == MGSL_MODE_RAW) {
+		unsigned int bufs_needed = (count/DMABUFSIZE);
+		unsigned int bufs_free = free_tbuf_count(info);
+		if (count % DMABUFSIZE)
+			++bufs_needed;
+		if (bufs_needed > bufs_free)
+			goto cleanup;
+	} else {
+		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(info, info->tx_buf, info->tx_count);
+			goto start;
+		}
+	}
+
+	ret = info->tx_count = count;
+	tx_load(info, buf, count);
+	goto start;
+
+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:
+	DBGINFO(("%s write rc=%d\n", info->device_name, ret));
+	return ret;
+}
+
+static void put_char(struct tty_struct *tty, unsigned char ch)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "put_char"))
+		return;
+	DBGINFO(("%s put_char(%d)\n", info->device_name, ch));
+	if (!tty || !info->tx_buf)
+		return;
+	spin_lock_irqsave(&info->lock,flags);
+	if (!info->tx_active && (info->tx_count < info->max_frame_size))
+		info->tx_buf[info->tx_count++] = ch;
+	spin_unlock_irqrestore(&info->lock,flags);
+}
+
+static void send_xchar(struct tty_struct *tty, char ch)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "send_xchar"))
+		return;
+	DBGINFO(("%s send_xchar(%d)\n", info->device_name, ch));
+	info->x_char = ch;
+	if (ch) {
+		spin_lock_irqsave(&info->lock,flags);
+		if (!info->tx_enabled)
+		 	tx_start(info);
+		spin_unlock_irqrestore(&info->lock,flags);
+	}
+}
+
+static void wait_until_sent(struct tty_struct *tty, int timeout)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long orig_jiffies, char_time;
+
+	if (!info )
+		return;
+	if (sanity_check(info, tty->name, "wait_until_sent"))
+		return;
+	DBGINFO(("%s wait_until_sent entry\n", info->device_name));
+	if (!(info->flags & ASYNC_INITIALIZED))
+		goto exit;
+
+	orig_jiffies = jiffies;
+
+	/* Set check interval to 1/5 of estimated time to
+	 * send a character, and make it at least 1. The check
+	 * interval should also be less than the timeout.
+	 * Note: use tight timings here to satisfy the NIST-PCTS.
+	 */
+
+	if (info->params.data_rate) {
+	       	char_time = info->timeout/(32 * 5);
+		if (!char_time)
+			char_time++;
+	} else
+		char_time = 1;
+
+	if (timeout)
+		char_time = min_t(unsigned long, char_time, timeout);
+
+	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;
+	}
+
+exit:
+	DBGINFO(("%s wait_until_sent exit\n", info->device_name));
+}
+
+static int write_room(struct tty_struct *tty)
+{
+	struct slgt_info *info = tty->driver_data;
+	int ret;
+
+	if (sanity_check(info, tty->name, "write_room"))
+		return 0;
+	ret = (info->tx_active) ? 0 : HDLC_MAX_FRAME_SIZE;
+	DBGINFO(("%s write_room=%d\n", info->device_name, ret));
+	return ret;
+}
+
+static void flush_chars(struct tty_struct *tty)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "flush_chars"))
+		return;
+	DBGINFO(("%s flush_chars entry tx_count=%d\n", info->device_name, info->tx_count));
+
+	if (info->tx_count <= 0 || tty->stopped ||
+	    tty->hw_stopped || !info->tx_buf)
+		return;
+
+	DBGINFO(("%s flush_chars start transmit\n", info->device_name));
+
+	spin_lock_irqsave(&info->lock,flags);
+	if (!info->tx_active && info->tx_count) {
+		tx_load(info, info->tx_buf,info->tx_count);
+	 	tx_start(info);
+	}
+	spin_unlock_irqrestore(&info->lock,flags);
+}
+
+static void flush_buffer(struct tty_struct *tty)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "flush_buffer"))
+		return;
+	DBGINFO(("%s flush_buffer\n", info->device_name));
+
+	spin_lock_irqsave(&info->lock,flags);
+	if (!info->tx_active)
+		info->tx_count = 0;
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	wake_up_interruptible(&tty->write_wait);
+	tty_wakeup(tty);
+}
+
+/*
+ * throttle (stop) transmitter
+ */
+static void tx_hold(struct tty_struct *tty)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "tx_hold"))
+		return;
+	DBGINFO(("%s tx_hold\n", info->device_name));
+	spin_lock_irqsave(&info->lock,flags);
+	if (info->tx_enabled && info->params.mode == MGSL_MODE_ASYNC)
+	 	tx_stop(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+}
+
+/*
+ * release (start) transmitter
+ */
+static void tx_release(struct tty_struct *tty)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "tx_release"))
+		return;
+	DBGINFO(("%s tx_release\n", info->device_name));
+	spin_lock_irqsave(&info->lock,flags);
+	if (!info->tx_active && info->tx_count) {
+		tx_load(info, info->tx_buf, info->tx_count);
+	 	tx_start(info);
+	}
+	spin_unlock_irqrestore(&info->lock,flags);
+}
+
+/*
+ * Service an IOCTL request
+ *
+ * Arguments
+ *
+ * 	tty	pointer to tty instance data
+ * 	file	pointer to associated file object for device
+ * 	cmd	IOCTL command code
+ * 	arg	command argument/context
+ *
+ * Return 0 if success, otherwise error code
+ */
+static int ioctl(struct tty_struct *tty, struct file *file,
+		 unsigned int cmd, unsigned long arg)
+{
+	struct slgt_info *info = tty->driver_data;
+	struct mgsl_icount cnow;	/* kernel counter temps */
+	struct serial_icounter_struct __user *p_cuser;	/* user space */
+	unsigned long flags;
+	void __user *argp = (void __user *)arg;
+
+	if (sanity_check(info, tty->name, "ioctl"))
+		return -ENODEV;
+	DBGINFO(("%s ioctl() cmd=%08X\n", info->device_name, cmd));
+
+	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
+	    (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
+		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 TIOCMIWAIT:
+		return modem_input_wait(info,(int)arg);
+	case MGSL_IOCGIF:
+		return get_interface(info, argp);
+	case MGSL_IOCSIF:
+		return set_interface(info,(int)arg);
+	case TIOCGICOUNT:
+		spin_lock_irqsave(&info->lock,flags);
+		cnow = info->icount;
+		spin_unlock_irqrestore(&info->lock,flags);
+		p_cuser = argp;
+		if (put_user(cnow.cts, &p_cuser->cts) ||
+		    put_user(cnow.dsr, &p_cuser->dsr) ||
+		    put_user(cnow.rng, &p_cuser->rng) ||
+		    put_user(cnow.dcd, &p_cuser->dcd) ||
+		    put_user(cnow.rx, &p_cuser->rx) ||
+		    put_user(cnow.tx, &p_cuser->tx) ||
+		    put_user(cnow.frame, &p_cuser->frame) ||
+		    put_user(cnow.overrun, &p_cuser->overrun) ||
+		    put_user(cnow.parity, &p_cuser->parity) ||
+		    put_user(cnow.brk, &p_cuser->brk) ||
+		    put_user(cnow.buf_overrun, &p_cuser->buf_overrun))
+			return -EFAULT;
+		return 0;
+	default:
+		return -ENOIOCTLCMD;
+	}
+	return 0;
+}
+
+/*
+ * proc fs support
+ */
+static inline int line_info(char *buf, struct slgt_info *info)
+{
+	char stat_buf[30];
+	int ret;
+	unsigned long flags;
+
+	ret = sprintf(buf, "%s: IO=%08X IRQ=%d MaxFrameSize=%u\n",
+		      info->device_name, info->phys_reg_addr,
+		      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->signals & SerialSignal_RTS)
+		strcat(stat_buf, "|RTS");
+	if (info->signals & SerialSignal_CTS)
+		strcat(stat_buf, "|CTS");
+	if (info->signals & SerialSignal_DTR)
+		strcat(stat_buf, "|DTR");
+	if (info->signals & SerialSignal_DSR)
+		strcat(stat_buf, "|DSR");
+	if (info->signals & SerialSignal_DCD)
+		strcat(stat_buf, "|CD");
+	if (info->signals & SerialSignal_RI)
+		strcat(stat_buf, "|RI");
+
+	if (info->params.mode != MGSL_MODE_ASYNC) {
+		ret += sprintf(buf+ret, "\tHDLC txok:%d rxok:%d",
+			       info->icount.txok, info->icount.rxok);
+		if (info->icount.txunder)
+			ret += sprintf(buf+ret, " txunder:%d", info->icount.txunder);
+		if (info->icount.txabort)
+			ret += sprintf(buf+ret, " txabort:%d", info->icount.txabort);
+		if (info->icount.rxshort)
+			ret += sprintf(buf+ret, " rxshort:%d", info->icount.rxshort);
+		if (info->icount.rxlong)
+			ret += sprintf(buf+ret, " rxlong:%d", info->icount.rxlong);
+		if (info->icount.rxover)
+			ret += sprintf(buf+ret, " rxover:%d", info->icount.rxover);
+		if (info->icount.rxcrc)
+			ret += sprintf(buf+ret, " rxcrc:%d", info->icount.rxcrc);
+	} else {
+		ret += sprintf(buf+ret, "\tASYNC tx:%d rx:%d",
+			       info->icount.tx, info->icount.rx);
+		if (info->icount.frame)
+			ret += sprintf(buf+ret, " fe:%d", info->icount.frame);
+		if (info->icount.parity)
+			ret += sprintf(buf+ret, " pe:%d", info->icount.parity);
+		if (info->icount.brk)
+			ret += sprintf(buf+ret, " brk:%d", info->icount.brk);
+		if (info->icount.overrun)
+			ret += sprintf(buf+ret, " oe:%d", info->icount.overrun);
+	}
+
+	/* Append serial signal status to end */
+	ret += sprintf(buf+ret, " %s\n", stat_buf+1);
+
+	ret += sprintf(buf+ret, "\ttxactive=%d bh_req=%d bh_run=%d pending_bh=%x\n",
+		       info->tx_active,info->bh_requested,info->bh_running,
+		       info->pending_bh);
+
+	return ret;
+}
+
+/* Called to print information about devices
+ */
+static int read_proc(char *page, char **start, off_t off, int count,
+		     int *eof, void *data)
+{
+	int len = 0, l;
+	off_t	begin = 0;
+	struct slgt_info *info;
+
+	len += sprintf(page, "synclink_gt driver:%s\n", driver_version);
+
+	info = slgt_device_list;
+	while( info ) {
+		l = line_info(page + len, info);
+		len += l;
+		if (len+begin > off+count)
+			goto done;
+		if (len+begin < off) {
+			begin += len;
+			len = 0;
+		}
+		info = info->next_device;
+	}
+
+	*eof = 1;
+done:
+	if (off >= len+begin)
+		return 0;
+	*start = page + (off-begin);
+	return ((count < begin+len-off) ? count : begin+len-off);
+}
+
+/*
+ * return count of bytes in transmit buffer
+ */
+static int chars_in_buffer(struct tty_struct *tty)
+{
+	struct slgt_info *info = tty->driver_data;
+	if (sanity_check(info, tty->name, "chars_in_buffer"))
+		return 0;
+	DBGINFO(("%s chars_in_buffer()=%d\n", 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)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "throttle"))
+		return;
+	DBGINFO(("%s throttle\n", info->device_name));
+	if (I_IXOFF(tty))
+		send_xchar(tty, STOP_CHAR(tty));
+ 	if (tty->termios->c_cflag & CRTSCTS) {
+		spin_lock_irqsave(&info->lock,flags);
+		info->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)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "unthrottle"))
+		return;
+	DBGINFO(("%s unthrottle\n", info->device_name));
+	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->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 void set_break(struct tty_struct *tty, int break_state)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned short value;
+	unsigned long flags;
+
+	if (sanity_check(info, tty->name, "set_break"))
+		return;
+	DBGINFO(("%s set_break(%d)\n", info->device_name, break_state));
+
+	spin_lock_irqsave(&info->lock,flags);
+	value = rd_reg16(info, TCR);
+ 	if (break_state == -1)
+		value |= BIT6;
+	else
+		value &= ~BIT6;
+	wr_reg16(info, TCR, value);
+	spin_unlock_irqrestore(&info->lock,flags);
+}
+
+#ifdef CONFIG_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)
+{
+	struct slgt_info *info = dev_to_port(dev);
+	unsigned char  new_encoding;
+	unsigned short new_crctype;
+
+	/* return error if TTY interface open */
+	if (info->count)
+		return -EBUSY;
+
+	DBGINFO(("%s hdlcdev_attach\n", info->device_name));
+
+	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
+ *
+ * returns 0 if success, otherwise error code
+ */
+static int hdlcdev_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct slgt_info *info = dev_to_port(dev);
+	struct net_device_stats *stats = hdlc_stats(dev);
+	unsigned long flags;
+
+	DBGINFO(("%s hdlc_xmit\n", dev->name));
+
+	/* stop sending until this frame completes */
+	netif_stop_queue(dev);
+
+	/* copy data to device buffers */
+	info->tx_count = skb->len;
+	tx_load(info, skb->data, skb->len);
+
+	/* update network statistics */
+	stats->tx_packets++;
+	stats->tx_bytes += skb->len;
+
+	/* done with socket buffer, so free it */
+	dev_kfree_skb(skb);
+
+	/* save start time for transmit timeout detection */
+	dev->trans_start = jiffies;
+
+	/* start hardware transmitter if necessary */
+	spin_lock_irqsave(&info->lock,flags);
+	if (!info->tx_active)
+	 	tx_start(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	return 0;
+}
+
+/**
+ * called by network layer when interface enabled
+ * claim resources and initialize hardware
+ *
+ * dev  pointer to network device structure
+ *
+ * returns 0 if success, otherwise error code
+ */
+static int hdlcdev_open(struct net_device *dev)
+{
+	struct slgt_info *info = dev_to_port(dev);
+	int rc;
+	unsigned long flags;
+
+	DBGINFO(("%s hdlcdev_open\n", dev->name));
+
+	/* generic HDLC layer open processing */
+	if ((rc = hdlc_open(dev)))
+		return rc;
+
+	/* arbitrate between network and tty opens */
+	spin_lock_irqsave(&info->netlock, flags);
+	if (info->count != 0 || info->netcount != 0) {
+		DBGINFO(("%s hdlc_open 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->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);
+	hdlc_set_carrier(info->signals & SerialSignal_DCD, 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)
+{
+	struct slgt_info *info = dev_to_port(dev);
+	unsigned long flags;
+
+	DBGINFO(("%s hdlcdev_close\n", 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;
+	struct slgt_info *info = dev_to_port(dev);
+	unsigned int flags;
+
+	DBGINFO(("%s hdlcdev_ioctl\n", dev->name));
+
+	/* return error if TTY interface open */
+	if (info->count)
+		return -EBUSY;
+
+	if (cmd != SIOCWANDEV)
+		return hdlc_ioctl(dev, ifr, cmd);
+
+	switch(ifr->ifr_settings.type) {
+	case IF_GET_IFACE: /* return current sync_serial_settings */
+
+		ifr->ifr_settings.type = IF_IFACE_SYNC_SERIAL;
+		if (ifr->ifr_settings.size < size) {
+			ifr->ifr_settings.size = size; /* data size wanted */
+			return -ENOBUFS;
+		}
+
+		flags = info->params.flags & (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
+					      HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
+					      HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
+					      HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN);
+
+		switch (flags){
+		case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_TXCPIN): new_line.clock_type = CLOCK_EXT; break;
+		case (HDLC_FLAG_RXC_BRG    | HDLC_FLAG_TXC_BRG):    new_line.clock_type = CLOCK_INT; break;
+		case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_BRG):    new_line.clock_type = CLOCK_TXINT; break;
+		case (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_RXCPIN): new_line.clock_type = CLOCK_TXFROMRX; break;
+		default: new_line.clock_type = CLOCK_DEFAULT;
+		}
+
+		new_line.clock_rate = info->params.clock_speed;
+		new_line.loopback   = info->params.loopback ? 1:0;
+
+		if (copy_to_user(line, &new_line, size))
+			return -EFAULT;
+		return 0;
+
+	case IF_IFACE_SYNC_SERIAL: /* set sync_serial_settings */
+
+		if(!capable(CAP_NET_ADMIN))
+			return -EPERM;
+		if (copy_from_user(&new_line, line, size))
+			return -EFAULT;
+
+		switch (new_line.clock_type)
+		{
+		case CLOCK_EXT:      flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_TXCPIN; break;
+		case CLOCK_TXFROMRX: flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_RXCPIN; break;
+		case CLOCK_INT:      flags = HDLC_FLAG_RXC_BRG    | HDLC_FLAG_TXC_BRG;    break;
+		case CLOCK_TXINT:    flags = HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_TXC_BRG;    break;
+		case CLOCK_DEFAULT:  flags = info->params.flags &
+					     (HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
+					      HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
+					      HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
+					      HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN); break;
+		default: return -EINVAL;
+		}
+
+		if (new_line.loopback != 0 && new_line.loopback != 1)
+			return -EINVAL;
+
+		info->params.flags &= ~(HDLC_FLAG_RXC_RXCPIN | HDLC_FLAG_RXC_DPLL |
+					HDLC_FLAG_RXC_BRG    | HDLC_FLAG_RXC_TXCPIN |
+					HDLC_FLAG_TXC_TXCPIN | HDLC_FLAG_TXC_DPLL |
+					HDLC_FLAG_TXC_BRG    | HDLC_FLAG_TXC_RXCPIN);
+		info->params.flags |= flags;
+
+		info->params.loopback = new_line.loopback;
+
+		if (flags & (HDLC_FLAG_RXC_BRG | HDLC_FLAG_TXC_BRG))
+			info->params.clock_speed = new_line.clock_rate;
+		else
+			info->params.clock_speed = 0;
+
+		/* if network interface up, reprogram hardware */
+		if (info->netcount)
+			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)
+{
+	struct slgt_info *info = dev_to_port(dev);
+	struct net_device_stats *stats = hdlc_stats(dev);
+	unsigned long flags;
+
+	DBGINFO(("%s hdlcdev_tx_timeout\n", dev->name));
+
+	stats->tx_errors++;
+	stats->tx_aborted_errors++;
+
+	spin_lock_irqsave(&info->lock,flags);
+	tx_stop(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	netif_wake_queue(dev);
+}
+
+/**
+ * called by device driver when transmit completes
+ * reenable network layer transmit if stopped
+ *
+ * info  pointer to device instance information
+ */
+static void hdlcdev_tx_done(struct slgt_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(struct slgt_info *info, char *buf, int size)
+{
+	struct sk_buff *skb = dev_alloc_skb(size);
+	struct net_device *dev = info->netdev;
+	struct net_device_stats *stats = hdlc_stats(dev);
+
+	DBGINFO(("%s hdlcdev_rx\n", dev->name));
+
+	if (skb == NULL) {
+		DBGERR(("%s: can't alloc skb, drop packet\n", dev->name));
+		stats->rx_dropped++;
+		return;
+	}
+
+	memcpy(skb_put(skb, size),buf,size);
+
+	skb->protocol = hdlc_type_trans(skb, info->netdev);
+
+	stats->rx_packets++;
+	stats->rx_bytes += size;
+
+	netif_rx(skb);
+
+	info->netdev->last_rx = jiffies;
+}
+
+/**
+ * called by device driver when adding device instance
+ * do generic HDLC initialization
+ *
+ * info  pointer to device instance information
+ *
+ * returns 0 if success, otherwise error code
+ */
+static int hdlcdev_init(struct slgt_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 alloc failure\n", info->device_name);
+		return -ENOMEM;
+	}
+
+	/* for network layer reporting purposes only */
+	dev->mem_start = info->phys_reg_addr;
+	dev->mem_end   = info->phys_reg_addr + SLGT_REG_SIZE - 1;
+	dev->irq       = info->irq_level;
+
+	/* network layer callbacks and settings */
+	dev->do_ioctl       = hdlcdev_ioctl;
+	dev->open           = hdlcdev_open;
+	dev->stop           = hdlcdev_close;
+	dev->tx_timeout     = hdlcdev_tx_timeout;
+	dev->watchdog_timeo = 10*HZ;
+	dev->tx_queue_len   = 50;
+
+	/* generic HDLC layer callbacks and settings */
+	hdlc         = dev_to_hdlc(dev);
+	hdlc->attach = hdlcdev_attach;
+	hdlc->xmit   = hdlcdev_xmit;
+
+	/* register objects with HDLC layer */
+	if ((rc = register_hdlc_device(dev))) {
+		printk(KERN_WARNING "%s:unable to register hdlc device\n",__FILE__);
+		free_netdev(dev);
+		return rc;
+	}
+
+	info->netdev = dev;
+	return 0;
+}
+
+/**
+ * called by device driver when removing device instance
+ * do generic HDLC cleanup
+ *
+ * info  pointer to device instance information
+ */
+static void hdlcdev_exit(struct slgt_info *info)
+{
+	unregister_hdlc_device(info->netdev);
+	free_netdev(info->netdev);
+	info->netdev = NULL;
+}
+
+#endif /* ifdef CONFIG_HDLC */
+
+/*
+ * get async data from rx DMA buffers
+ */
+static void rx_async(struct slgt_info *info)
+{
+ 	struct tty_struct *tty = info->tty;
+ 	struct mgsl_icount *icount = &info->icount;
+	unsigned int start, end;
+	unsigned char *p;
+	unsigned char status;
+	struct slgt_desc *bufs = info->rbufs;
+	int i, count;
+
+	start = end = info->rbuf_current;
+
+	while(desc_complete(bufs[end])) {
+		count = desc_count(bufs[end]) - info->rbuf_index;
+		p     = bufs[end].buf + info->rbuf_index;
+
+		DBGISR(("%s rx_async count=%d\n", info->device_name, count));
+		DBGDATA(info, p, count, "rx");
+
+		for(i=0 ; i < count; i+=2, p+=2) {
+			if (tty) {
+				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
+					tty_flip_buffer_push(tty);
+				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
+					break;
+				*tty->flip.char_buf_ptr = *p;
+				*tty->flip.flag_buf_ptr = 0;
+			}
+			icount->rx++;
+
+			if ((status = *(p+1) & (BIT9 + BIT8))) {
+				if (status & BIT9)
+					icount->parity++;
+				else if (status & BIT8)
+					icount->frame++;
+				/* discard char if tty control flags say so */
+				if (status & info->ignore_status_mask)
+					continue;
+				if (tty) {
+					if (status & BIT9)
+						*tty->flip.flag_buf_ptr = TTY_PARITY;
+					else if (status & BIT8)
+						*tty->flip.flag_buf_ptr = TTY_FRAME;
+				}
+			}
+			if (tty) {
+				tty->flip.flag_buf_ptr++;
+				tty->flip.char_buf_ptr++;
+				tty->flip.count++;
+			}
+		}
+
+		if (i < count) {
+			/* receive buffer not completed */
+			info->rbuf_index += i;
+			info->rx_timer.expires = jiffies + 1;
+			add_timer(&info->rx_timer);
+			break;
+		}
+
+		info->rbuf_index = 0;
+		free_rbufs(info, end, end);
+
+		if (++end == info->rbuf_count)
+			end = 0;
+
+		/* if entire list searched then no frame available */
+		if (end == start)
+			break;
+	}
+
+	if (tty && tty->flip.count)
+		tty_flip_buffer_push(tty);
+}
+
+/*
+ * return next bottom half action to perform
+ */
+static int bh_action(struct slgt_info *info)
+{
+	unsigned long flags;
+	int rc;
+
+	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;
+	} else {
+		/* Mark BH routine as complete */
+		info->bh_running   = 0;
+		info->bh_requested = 0;
+		rc = 0;
+	}
+
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	return rc;
+}
+
+/*
+ * perform bottom half processing
+ */
+static void bh_handler(void* context)
+{
+	struct slgt_info *info = context;
+	int action;
+
+	if (!info)
+		return;
+	info->bh_running = 1;
+
+	while((action = bh_action(info))) {
+		switch (action) {
+		case BH_RECEIVE:
+			DBGBH(("%s bh receive\n", info->device_name));
+			switch(info->params.mode) {
+			case MGSL_MODE_ASYNC:
+				rx_async(info);
+				break;
+			case MGSL_MODE_HDLC:
+				while(rx_get_frame(info));
+				break;
+			case MGSL_MODE_RAW:
+				while(rx_get_buf(info));
+				break;
+			}
+			/* restart receiver if rx DMA buffers exhausted */
+			if (info->rx_restart)
+				rx_start(info);
+			break;
+		case BH_TRANSMIT:
+			bh_transmit(info);
+			break;
+		case BH_STATUS:
+			DBGBH(("%s bh status\n", info->device_name));
+			info->ri_chkcount = 0;
+			info->dsr_chkcount = 0;
+			info->dcd_chkcount = 0;
+			info->cts_chkcount = 0;
+			break;
+		default:
+			DBGBH(("%s unknown action\n", info->device_name));
+			break;
+		}
+	}
+	DBGBH(("%s bh_handler exit\n", info->device_name));
+}
+
+static void bh_transmit(struct slgt_info *info)
+{
+	struct tty_struct *tty = info->tty;
+
+	DBGBH(("%s bh_transmit\n", info->device_name));
+	if (tty) {
+		tty_wakeup(tty);
+		wake_up_interruptible(&tty->write_wait);
+	}
+}
+
+static void dsr_change(struct slgt_info *info)
+{
+	get_signals(info);
+	DBGISR(("dsr_change %s signals=%04X\n", info->device_name, info->signals));
+	if ((info->dsr_chkcount)++ == IO_PIN_SHUTDOWN_LIMIT) {
+		slgt_irq_off(info, IRQ_DSR);
+		return;
+	}
+	info->icount.dsr++;
+	if (info->signals & SerialSignal_DSR)
+		info->input_signal_events.dsr_up++;
+	else
+		info->input_signal_events.dsr_down++;
+	wake_up_interruptible(&info->status_event_wait_q);
+	wake_up_interruptible(&info->event_wait_q);
+	info->pending_bh |= BH_STATUS;
+}
+
+static void cts_change(struct slgt_info *info)
+{
+	get_signals(info);
+	DBGISR(("cts_change %s signals=%04X\n", info->device_name, info->signals));
+	if ((info->cts_chkcount)++ == IO_PIN_SHUTDOWN_LIMIT) {
+		slgt_irq_off(info, IRQ_CTS);
+		return;
+	}
+	info->icount.cts++;
+	if (info->signals & SerialSignal_CTS)
+		info->input_signal_events.cts_up++;
+	else
+		info->input_signal_events.cts_down++;
+	wake_up_interruptible(&info->status_event_wait_q);
+	wake_up_interruptible(&info->event_wait_q);
+	info->pending_bh |= BH_STATUS;
+
+	if (info->flags & ASYNC_CTS_FLOW) {
+		if (info->tty) {
+			if (info->tty->hw_stopped) {
+				if (info->signals & SerialSignal_CTS) {
+		 			info->tty->hw_stopped = 0;
+					info->pending_bh |= BH_TRANSMIT;
+					return;
+				}
+			} else {
+				if (!(info->signals & SerialSignal_CTS))
+		 			info->tty->hw_stopped = 1;
+			}
+		}
+	}
+}
+
+static void dcd_change(struct slgt_info *info)
+{
+	get_signals(info);
+	DBGISR(("dcd_change %s signals=%04X\n", info->device_name, info->signals));
+	if ((info->dcd_chkcount)++ == IO_PIN_SHUTDOWN_LIMIT) {
+		slgt_irq_off(info, IRQ_DCD);
+		return;
+	}
+	info->icount.dcd++;
+	if (info->signals & SerialSignal_DCD) {
+		info->input_signal_events.dcd_up++;
+	} else {
+		info->input_signal_events.dcd_down++;
+	}
+#ifdef CONFIG_HDLC
+	if (info->netcount)
+		hdlc_set_carrier(info->signals & SerialSignal_DCD, info->netdev);
+#endif
+	wake_up_interruptible(&info->status_event_wait_q);
+	wake_up_interruptible(&info->event_wait_q);
+	info->pending_bh |= BH_STATUS;
+
+	if (info->flags & ASYNC_CHECK_CD) {
+		if (info->signals & SerialSignal_DCD)
+			wake_up_interruptible(&info->open_wait);
+		else {
+			if (info->tty)
+				tty_hangup(info->tty);
+		}
+	}
+}
+
+static void ri_change(struct slgt_info *info)
+{
+	get_signals(info);
+	DBGISR(("ri_change %s signals=%04X\n", info->device_name, info->signals));
+	if ((info->ri_chkcount)++ == IO_PIN_SHUTDOWN_LIMIT) {
+		slgt_irq_off(info, IRQ_RI);
+		return;
+	}
+	info->icount.dcd++;
+	if (info->signals & SerialSignal_RI) {
+		info->input_signal_events.ri_up++;
+	} else {
+		info->input_signal_events.ri_down++;
+	}
+	wake_up_interruptible(&info->status_event_wait_q);
+	wake_up_interruptible(&info->event_wait_q);
+	info->pending_bh |= BH_STATUS;
+}
+
+static void isr_serial(struct slgt_info *info)
+{
+	unsigned short status = rd_reg16(info, SSR);
+
+	DBGISR(("%s isr_serial status=%04X\n", info->device_name, status));
+
+	wr_reg16(info, SSR, status); /* clear pending */
+
+	info->irq_occurred = 1;
+
+	if (info->params.mode == MGSL_MODE_ASYNC) {
+		if (status & IRQ_TXIDLE) {
+			if (info->tx_count)
+				isr_txeom(info, status);
+		}
+		if ((status & IRQ_RXBREAK) && (status & RXBREAK)) {
+			info->icount.brk++;
+			/* process break detection if tty control allows */
+			if (info->tty) {
+				if (!(status & info->ignore_status_mask)) {
+					if (info->read_status_mask & MASK_BREAK) {
+						*info->tty->flip.flag_buf_ptr = TTY_BREAK;
+						if (info->flags & ASYNC_SAK)
+							do_SAK(info->tty);
+					}
+				}
+			}
+		}
+	} else {
+		if (status & (IRQ_TXIDLE + IRQ_TXUNDER))
+			isr_txeom(info, status);
+
+		if (status & IRQ_RXIDLE) {
+			if (status & RXIDLE)
+				info->icount.rxidle++;
+			else
+				info->icount.exithunt++;
+			wake_up_interruptible(&info->event_wait_q);
+		}
+
+		if (status & IRQ_RXOVER)
+			rx_start(info);
+	}
+
+	if (status & IRQ_DSR)
+		dsr_change(info);
+	if (status & IRQ_CTS)
+		cts_change(info);
+	if (status & IRQ_DCD)
+		dcd_change(info);
+	if (status & IRQ_RI)
+		ri_change(info);
+}
+
+static void isr_rdma(struct slgt_info *info)
+{
+	unsigned int status = rd_reg32(info, RDCSR);
+
+	DBGISR(("%s isr_rdma status=%08x\n", info->device_name, status));
+
+	/* RDCSR (rx DMA control/status)
+	 *
+	 * 31..07  reserved
+	 * 06      save status byte to DMA buffer
+	 * 05      error
+	 * 04      eol (end of list)
+	 * 03      eob (end of buffer)
+	 * 02      IRQ enable
+	 * 01      reset
+	 * 00      enable
+	 */
+	wr_reg32(info, RDCSR, status);	/* clear pending */
+
+	if (status & (BIT5 + BIT4)) {
+		DBGISR(("%s isr_rdma rx_restart=1\n", info->device_name));
+		info->rx_restart = 1;
+	}
+	info->pending_bh |= BH_RECEIVE;
+}
+
+static void isr_tdma(struct slgt_info *info)
+{
+	unsigned int status = rd_reg32(info, TDCSR);
+
+	DBGISR(("%s isr_tdma status=%08x\n", info->device_name, status));
+
+	/* TDCSR (tx DMA control/status)
+	 *
+	 * 31..06  reserved
+	 * 05      error
+	 * 04      eol (end of list)
+	 * 03      eob (end of buffer)
+	 * 02      IRQ enable
+	 * 01      reset
+	 * 00      enable
+	 */
+	wr_reg32(info, TDCSR, status);	/* clear pending */
+
+	if (status & (BIT5 + BIT4 + BIT3)) {
+		// another transmit buffer has completed
+		// run bottom half to get more send data from user
+		info->pending_bh |= BH_TRANSMIT;
+	}
+}
+
+static void isr_txeom(struct slgt_info *info, unsigned short status)
+{
+	DBGISR(("%s txeom status=%04x\n", info->device_name, status));
+
+	slgt_irq_off(info, IRQ_TXDATA + IRQ_TXIDLE + IRQ_TXUNDER);
+	tdma_reset(info);
+	reset_tbufs(info);
+	if (status & IRQ_TXUNDER) {
+		unsigned short val = rd_reg16(info, TCR);
+		wr_reg16(info, TCR, (unsigned short)(val | BIT2)); /* set reset bit */
+		wr_reg16(info, TCR, val); /* clear reset bit */
+	}
+
+	if (info->tx_active) {
+		if (info->params.mode != MGSL_MODE_ASYNC) {
+			if (status & IRQ_TXUNDER)
+				info->icount.txunder++;
+			else if (status & IRQ_TXIDLE)
+				info->icount.txok++;
+		}
+
+		info->tx_active = 0;
+		info->tx_count = 0;
+
+		del_timer(&info->tx_timer);
+
+		if (info->params.mode != MGSL_MODE_ASYNC && info->drop_rts_on_tx_done) {
+			info->signals &= ~SerialSignal_RTS;
+			info->drop_rts_on_tx_done = 0;
+			set_signals(info);
+		}
+
+#ifdef CONFIG_HDLC
+		if (info->netcount)
+			hdlcdev_tx_done(info);
+		else
+#endif
+		{
+			if (info->tty && (info->tty->stopped || info->tty->hw_stopped)) {
+				tx_stop(info);
+				return;
+			}
+			info->pending_bh |= BH_TRANSMIT;
+		}
+	}
+}
+
+/* interrupt service routine
+ *
+ * 	irq	interrupt number
+ * 	dev_id	device ID supplied during interrupt registration
+ * 	regs	interrupted processor context
+ */
+static irqreturn_t slgt_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+{
+	struct slgt_info *info;
+	unsigned int gsr;
+	unsigned int i;
+
+	DBGISR(("slgt_interrupt irq=%d entry\n", irq));
+
+	info = dev_id;
+	if (!info)
+		return IRQ_NONE;
+
+	spin_lock(&info->lock);
+
+	while((gsr = rd_reg32(info, GSR) & 0xffffff00)) {
+		DBGISR(("%s gsr=%08x\n", info->device_name, gsr));
+		info->irq_occurred = 1;
+		for(i=0; i < info->port_count ; i++) {
+			if (info->port_array[i] == NULL)
+				continue;
+			if (gsr & (BIT8 << i))
+				isr_serial(info->port_array[i]);
+			if (gsr & (BIT16 << (i*2)))
+				isr_rdma(info->port_array[i]);
+			if (gsr & (BIT17 << (i*2)))
+				isr_tdma(info->port_array[i]);
+		}
+	}
+
+	for(i=0; i < info->port_count ; i++) {
+		struct slgt_info *port = info->port_array[i];
+
+		if (port && (port->count || port->netcount) &&
+		    port->pending_bh && !port->bh_running &&
+		    !port->bh_requested) {
+			DBGISR(("%s bh queued\n", port->device_name));
+			schedule_work(&port->task);
+			port->bh_requested = 1;
+		}
+	}
+
+	spin_unlock(&info->lock);
+
+	DBGISR(("slgt_interrupt irq=%d exit\n", irq));
+	return IRQ_HANDLED;
+}
+
+static int startup(struct slgt_info *info)
+{
+	DBGINFO(("%s startup\n", info->device_name));
+
+	if (info->flags & ASYNC_INITIALIZED)
+		return 0;
+
+	if (!info->tx_buf) {
+		info->tx_buf = kmalloc(info->max_frame_size, GFP_KERNEL);
+		if (!info->tx_buf) {
+			DBGERR(("%s can't allocate tx buffer\n", info->device_name));
+			return -ENOMEM;
+		}
+	}
+
+	info->pending_bh = 0;
+
+	memset(&info->icount, 0, sizeof(info->icount));
+
+	/* program hardware for current parameters */
+	change_params(info);
+
+	if (info->tty)
+		clear_bit(TTY_IO_ERROR, &info->tty->flags);
+
+	info->flags |= ASYNC_INITIALIZED;
+
+	return 0;
+}
+
+/*
+ *  called by close() and hangup() to shutdown hardware
+ */
+static void shutdown(struct slgt_info *info)
+{
+	unsigned long flags;
+
+	if (!(info->flags & ASYNC_INITIALIZED))
+		return;
+
+	DBGINFO(("%s shutdown\n", 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);
+	del_timer_sync(&info->rx_timer);
+
+	kfree(info->tx_buf);
+	info->tx_buf = NULL;
+
+	spin_lock_irqsave(&info->lock,flags);
+
+	tx_stop(info);
+	rx_stop(info);
+
+	slgt_irq_off(info, IRQ_ALL | IRQ_MASTER);
+
+ 	if (!info->tty || info->tty->termios->c_cflag & HUPCL) {
+ 		info->signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
+		set_signals(info);
+	}
+
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	if (info->tty)
+		set_bit(TTY_IO_ERROR, &info->tty->flags);
+
+	info->flags &= ~ASYNC_INITIALIZED;
+}
+
+static void program_hw(struct slgt_info *info)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&info->lock,flags);
+
+	rx_stop(info);
+	tx_stop(info);
+
+	if (info->params.mode == MGSL_MODE_HDLC ||
+	    info->params.mode == MGSL_MODE_RAW ||
+	    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;
+
+	slgt_irq_on(info, IRQ_DCD | IRQ_CTS | IRQ_DSR);
+	get_signals(info);
+
+	if (info->netcount ||
+	    (info->tty && info->tty->termios->c_cflag & CREAD))
+		rx_start(info);
+
+	spin_unlock_irqrestore(&info->lock,flags);
+}
+
+/*
+ * reconfigure adapter based on new parameters
+ */
+static void change_params(struct slgt_info *info)
+{
+	unsigned cflag;
+	int bits_per_char;
+
+	if (!info->tty || !info->tty->termios)
+		return;
+	DBGINFO(("%s change_params\n", info->device_name));
+
+	cflag = info->tty->termios->c_cflag;
+
+	/* if B0 rate (hangup) specified then negate DTR and RTS */
+	/* otherwise assert DTR and RTS */
+ 	if (cflag & CBAUD)
+		info->signals |= SerialSignal_RTS + SerialSignal_DTR;
+	else
+		info->signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+
+	/* byte size and parity */
+
+	switch (cflag & CSIZE) {
+	case CS5: info->params.data_bits = 5; break;
+	case CS6: info->params.data_bits = 6; break;
+	case CS7: info->params.data_bits = 7; break;
+	case CS8: info->params.data_bits = 8; break;
+	default:  info->params.data_bits = 7; break;
+	}
+
+	info->params.stop_bits = (cflag & CSTOPB) ? 2 : 1;
+
+	if (cflag & PARENB)
+		info->params.parity = (cflag & PARODD) ? ASYNC_PARITY_ODD : ASYNC_PARITY_EVEN;
+	else
+		info->params.parity = ASYNC_PARITY_NONE;
+
+	/* 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;
+
+	info->params.data_rate = tty_get_baud_rate(info->tty);
+
+	if (info->params.data_rate) {
+		info->timeout = (32*HZ*bits_per_char) /
+				info->params.data_rate;
+	}
+	info->timeout += HZ/50;		/* Add .02 seconds of slop */
+
+	if (cflag & CRTSCTS)
+		info->flags |= ASYNC_CTS_FLOW;
+	else
+		info->flags &= ~ASYNC_CTS_FLOW;
+
+	if (cflag & CLOCAL)
+		info->flags &= ~ASYNC_CHECK_CD;
+	else
+		info->flags |= ASYNC_CHECK_CD;
+
+	/* process tty input control flags */
+
+	info->read_status_mask = IRQ_RXOVER;
+	if (I_INPCK(info->tty))
+		info->read_status_mask |= MASK_PARITY | MASK_FRAMING;
+ 	if (I_BRKINT(info->tty) || I_PARMRK(info->tty))
+ 		info->read_status_mask |= MASK_BREAK;
+	if (I_IGNPAR(info->tty))
+		info->ignore_status_mask |= MASK_PARITY | MASK_FRAMING;
+	if (I_IGNBRK(info->tty)) {
+		info->ignore_status_mask |= MASK_BREAK;
+		/* If ignoring parity and break indicators, ignore
+		 * overruns too.  (For real raw support).
+		 */
+		if (I_IGNPAR(info->tty))
+			info->ignore_status_mask |= MASK_OVERRUN;
+	}
+
+	program_hw(info);
+}
+
+static int get_stats(struct slgt_info *info, struct mgsl_icount __user *user_icount)
+{
+	DBGINFO(("%s get_stats\n",  info->device_name));
+	if (!user_icount) {
+		memset(&info->icount, 0, sizeof(info->icount));
+	} else {
+		if (copy_to_user(user_icount, &info->icount, sizeof(struct mgsl_icount)))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+static int get_params(struct slgt_info *info, MGSL_PARAMS __user *user_params)
+{
+	DBGINFO(("%s get_params\n", info->device_name));
+	if (copy_to_user(user_params, &info->params, sizeof(MGSL_PARAMS)))
+		return -EFAULT;
+	return 0;
+}
+
+static int set_params(struct slgt_info *info, MGSL_PARAMS __user *new_params)
+{
+ 	unsigned long flags;
+	MGSL_PARAMS tmp_params;
+
+	DBGINFO(("%s set_params\n", info->device_name));
+	if (copy_from_user(&tmp_params, new_params, sizeof(MGSL_PARAMS)))
+		return -EFAULT;
+
+	spin_lock_irqsave(&info->lock, flags);
+	memcpy(&info->params, &tmp_params, sizeof(MGSL_PARAMS));
+	spin_unlock_irqrestore(&info->lock, flags);
+
+ 	change_params(info);
+
+	return 0;
+}
+
+static int get_txidle(struct slgt_info *info, int __user *idle_mode)
+{
+	DBGINFO(("%s get_txidle=%d\n", info->device_name, info->idle_mode));
+	if (put_user(info->idle_mode, idle_mode))
+		return -EFAULT;
+	return 0;
+}
+
+static int set_txidle(struct slgt_info *info, int idle_mode)
+{
+ 	unsigned long flags;
+	DBGINFO(("%s set_txidle(%d)\n", info->device_name, idle_mode));
+	spin_lock_irqsave(&info->lock,flags);
+	info->idle_mode = idle_mode;
+	tx_set_idle(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+	return 0;
+}
+
+static int tx_enable(struct slgt_info *info, int enable)
+{
+ 	unsigned long flags;
+	DBGINFO(("%s tx_enable(%d)\n", info->device_name, enable));
+	spin_lock_irqsave(&info->lock,flags);
+	if (enable) {
+		if (!info->tx_enabled)
+			tx_start(info);
+	} else {
+		if (info->tx_enabled)
+			tx_stop(info);
+	}
+	spin_unlock_irqrestore(&info->lock,flags);
+	return 0;
+}
+
+/*
+ * abort transmit HDLC frame
+ */
+static int tx_abort(struct slgt_info *info)
+{
+ 	unsigned long flags;
+	DBGINFO(("%s tx_abort\n", info->device_name));
+	spin_lock_irqsave(&info->lock,flags);
+	tdma_reset(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+	return 0;
+}
+
+static int rx_enable(struct slgt_info *info, int enable)
+{
+ 	unsigned long flags;
+	DBGINFO(("%s rx_enable(%d)\n", info->device_name, enable));
+	spin_lock_irqsave(&info->lock,flags);
+	if (enable) {
+		if (!info->rx_enabled)
+			rx_start(info);
+	} else {
+		if (info->rx_enabled)
+			rx_stop(info);
+	}
+	spin_unlock_irqrestore(&info->lock,flags);
+	return 0;
+}
+
+/*
+ *  wait for specified event to occur
+ */
+static int wait_mgsl_event(struct slgt_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);
+
+	if (get_user(mask, mask_ptr))
+		return -EFAULT;
+
+	DBGINFO(("%s wait_mgsl_event(%d)\n", info->device_name, mask));
+
+	spin_lock_irqsave(&info->lock,flags);
+
+	/* return immediately if state matches requested events */
+	get_signals(info);
+	s = info->signals;
+
+	events = mask &
+		( ((s & SerialSignal_DSR) ? MgslEvent_DsrActive:MgslEvent_DsrInactive) +
+ 		  ((s & SerialSignal_DCD) ? MgslEvent_DcdActive:MgslEvent_DcdInactive) +
+		  ((s & SerialSignal_CTS) ? MgslEvent_CtsActive:MgslEvent_CtsInactive) +
+		  ((s & SerialSignal_RI)  ? MgslEvent_RiActive :MgslEvent_RiInactive) );
+	if (events) {
+		spin_unlock_irqrestore(&info->lock,flags);
+		goto exit;
+	}
+
+	/* save current irq counts */
+	cprev = info->icount;
+	oldsigs = info->input_signal_events;
+
+	/* enable hunt and idle irqs if needed */
+	if (mask & (MgslEvent_ExitHuntMode+MgslEvent_IdleReceived)) {
+		unsigned short val = rd_reg16(info, SCR);
+		if (!(val & IRQ_RXIDLE))
+			wr_reg16(info, SCR, (unsigned short)(val | IRQ_RXIDLE));
+	}
+
+	set_current_state(TASK_INTERRUPTIBLE);
+	add_wait_queue(&info->event_wait_q, &wait);
+
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	for(;;) {
+		schedule();
+		if (signal_pending(current)) {
+			rc = -ERESTARTSYS;
+			break;
+		}
+
+		/* get current irq counts */
+		spin_lock_irqsave(&info->lock,flags);
+		cnow = info->icount;
+		newsigs = info->input_signal_events;
+		set_current_state(TASK_INTERRUPTIBLE);
+		spin_unlock_irqrestore(&info->lock,flags);
+
+		/* if no change, wait aborted for some reason */
+		if (newsigs.dsr_up   == oldsigs.dsr_up   &&
+		    newsigs.dsr_down == oldsigs.dsr_down &&
+		    newsigs.dcd_up   == oldsigs.dcd_up   &&
+		    newsigs.dcd_down == oldsigs.dcd_down &&
+		    newsigs.cts_up   == oldsigs.cts_up   &&
+		    newsigs.cts_down == oldsigs.cts_down &&
+		    newsigs.ri_up    == oldsigs.ri_up    &&
+		    newsigs.ri_down  == oldsigs.ri_down  &&
+		    cnow.exithunt    == cprev.exithunt   &&
+		    cnow.rxidle      == cprev.rxidle) {
+			rc = -EIO;
+			break;
+		}
+
+		events = mask &
+			( (newsigs.dsr_up   != oldsigs.dsr_up   ? MgslEvent_DsrActive:0)   +
+			  (newsigs.dsr_down != oldsigs.dsr_down ? MgslEvent_DsrInactive:0) +
+			  (newsigs.dcd_up   != oldsigs.dcd_up   ? MgslEvent_DcdActive:0)   +
+			  (newsigs.dcd_down != oldsigs.dcd_down ? MgslEvent_DcdInactive:0) +
+			  (newsigs.cts_up   != oldsigs.cts_up   ? MgslEvent_CtsActive:0)   +
+			  (newsigs.cts_down != oldsigs.cts_down ? MgslEvent_CtsInactive:0) +
+			  (newsigs.ri_up    != oldsigs.ri_up    ? MgslEvent_RiActive:0)    +
+			  (newsigs.ri_down  != oldsigs.ri_down  ? MgslEvent_RiInactive:0)  +
+			  (cnow.exithunt    != cprev.exithunt   ? MgslEvent_ExitHuntMode:0) +
+			  (cnow.rxidle      != cprev.rxidle     ? MgslEvent_IdleReceived:0) );
+		if (events)
+			break;
+
+		cprev = cnow;
+		oldsigs = newsigs;
+	}
+
+	remove_wait_queue(&info->event_wait_q, &wait);
+	set_current_state(TASK_RUNNING);
+
+
+	if (mask & (MgslEvent_ExitHuntMode + MgslEvent_IdleReceived)) {
+		spin_lock_irqsave(&info->lock,flags);
+		if (!waitqueue_active(&info->event_wait_q)) {
+			/* disable enable exit hunt mode/idle rcvd IRQs */
+			wr_reg16(info, SCR,
+				(unsigned short)(rd_reg16(info, SCR) & ~IRQ_RXIDLE));
+		}
+		spin_unlock_irqrestore(&info->lock,flags);
+	}
+exit:
+	if (rc == 0)
+		rc = put_user(events, mask_ptr);
+	return rc;
+}
+
+static int get_interface(struct slgt_info *info, int __user *if_mode)
+{
+	DBGINFO(("%s get_interface=%x\n", info->device_name, info->if_mode));
+	if (put_user(info->if_mode, if_mode))
+		return -EFAULT;
+	return 0;
+}
+
+static int set_interface(struct slgt_info *info, int if_mode)
+{
+ 	unsigned long flags;
+	unsigned char val;
+
+	DBGINFO(("%s set_interface=%x)\n", info->device_name, if_mode));
+	spin_lock_irqsave(&info->lock,flags);
+	info->if_mode = if_mode;
+
+	msc_set_vcr(info);
+
+	/* TCR (tx control) 07  1=RTS driver control */
+	val = rd_reg16(info, TCR);
+	if (info->if_mode & MGSL_INTERFACE_RTS_EN)
+		val |= BIT7;
+	else
+		val &= ~BIT7;
+	wr_reg16(info, TCR, val);
+
+	spin_unlock_irqrestore(&info->lock,flags);
+	return 0;
+}
+
+static int modem_input_wait(struct slgt_info *info,int arg)
+{
+ 	unsigned long flags;
+	int rc;
+	struct mgsl_icount cprev, cnow;
+	DECLARE_WAITQUEUE(wait, current);
+
+	/* save current irq counts */
+	spin_lock_irqsave(&info->lock,flags);
+	cprev = info->icount;
+	add_wait_queue(&info->status_event_wait_q, &wait);
+	set_current_state(TASK_INTERRUPTIBLE);
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	for(;;) {
+		schedule();
+		if (signal_pending(current)) {
+			rc = -ERESTARTSYS;
+			break;
+		}
+
+		/* get new irq counts */
+		spin_lock_irqsave(&info->lock,flags);
+		cnow = info->icount;
+		set_current_state(TASK_INTERRUPTIBLE);
+		spin_unlock_irqrestore(&info->lock,flags);
+
+		/* if no change, wait aborted for some reason */
+		if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
+		    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) {
+			rc = -EIO;
+			break;
+		}
+
+		/* check for change in caller specified modem input */
+		if ((arg & TIOCM_RNG && cnow.rng != cprev.rng) ||
+		    (arg & TIOCM_DSR && cnow.dsr != cprev.dsr) ||
+		    (arg & TIOCM_CD  && cnow.dcd != cprev.dcd) ||
+		    (arg & TIOCM_CTS && cnow.cts != cprev.cts)) {
+			rc = 0;
+			break;
+		}
+
+		cprev = cnow;
+	}
+	remove_wait_queue(&info->status_event_wait_q, &wait);
+	set_current_state(TASK_RUNNING);
+	return rc;
+}
+
+/*
+ *  return state of serial control and status signals
+ */
+static int tiocmget(struct tty_struct *tty, struct file *file)
+{
+	struct slgt_info *info = tty->driver_data;
+	unsigned int result;
+ 	unsigned long flags;
+
+	spin_lock_irqsave(&info->lock,flags);
+ 	get_signals(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	result = ((info->signals & SerialSignal_RTS) ? TIOCM_RTS:0) +
+		((info->signals & SerialSignal_DTR) ? TIOCM_DTR:0) +
+		((info->signals & SerialSignal_DCD) ? TIOCM_CAR:0) +
+		((info->signals & SerialSignal_RI)  ? TIOCM_RNG:0) +
+		((info->signals & SerialSignal_DSR) ? TIOCM_DSR:0) +
+		((info->signals & SerialSignal_CTS) ? TIOCM_CTS:0);
+
+	DBGINFO(("%s tiocmget value=%08X\n", info->device_name, result));
+	return result;
+}
+
+/*
+ * set modem control signals (DTR/RTS)
+ *
+ * 	cmd	signal command: TIOCMBIS = set bit TIOCMBIC = clear bit
+ *		TIOCMSET = set/clear signal values
+ * 	value	bit mask for command
+ */
+static int tiocmset(struct tty_struct *tty, struct file *file,
+		    unsigned int set, unsigned int clear)
+{
+	struct slgt_info *info = tty->driver_data;
+ 	unsigned long flags;
+
+	DBGINFO(("%s tiocmset(%x,%x)\n", info->device_name, set, clear));
+
+	if (set & TIOCM_RTS)
+		info->signals |= SerialSignal_RTS;
+	if (set & TIOCM_DTR)
+		info->signals |= SerialSignal_DTR;
+	if (clear & TIOCM_RTS)
+		info->signals &= ~SerialSignal_RTS;
+	if (clear & TIOCM_DTR)
+		info->signals &= ~SerialSignal_DTR;
+
+	spin_lock_irqsave(&info->lock,flags);
+ 	set_signals(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+	return 0;
+}
+
+/*
+ *  block current process until the device is ready to open
+ */
+static int block_til_ready(struct tty_struct *tty, struct file *filp,
+			   struct slgt_info *info)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	int		retval;
+	int		do_clocal = 0, extra_count = 0;
+	unsigned long	flags;
+
+	DBGINFO(("%s block_til_ready\n", tty->driver->name));
+
+	if (filp->f_flags & O_NONBLOCK || tty->flags & (1 << TTY_IO_ERROR)){
+		/* nonblock mode is set or port is not enabled */
+		info->flags |= ASYNC_NORMAL_ACTIVE;
+		return 0;
+	}
+
+	if (tty->termios->c_cflag & CLOCAL)
+		do_clocal = 1;
+
+	/* Wait for carrier detect and the line to become
+	 * free (i.e., not in use by the callout).  While we are in
+	 * this loop, info->count is dropped by one, so that
+	 * close() knows when to free things.  We restore it upon
+	 * exit, either normal or abnormal.
+	 */
+
+	retval = 0;
+	add_wait_queue(&info->open_wait, &wait);
+
+	spin_lock_irqsave(&info->lock, flags);
+	if (!tty_hung_up_p(filp)) {
+		extra_count = 1;
+		info->count--;
+	}
+	spin_unlock_irqrestore(&info->lock, flags);
+	info->blocked_open++;
+
+	while (1) {
+		if ((tty->termios->c_cflag & CBAUD)) {
+			spin_lock_irqsave(&info->lock,flags);
+			info->signals |= SerialSignal_RTS + SerialSignal_DTR;
+		 	set_signals(info);
+			spin_unlock_irqrestore(&info->lock,flags);
+		}
+
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		if (tty_hung_up_p(filp) || !(info->flags & ASYNC_INITIALIZED)){
+			retval = (info->flags & ASYNC_HUP_NOTIFY) ?
+					-EAGAIN : -ERESTARTSYS;
+			break;
+		}
+
+		spin_lock_irqsave(&info->lock,flags);
+	 	get_signals(info);
+		spin_unlock_irqrestore(&info->lock,flags);
+
+ 		if (!(info->flags & ASYNC_CLOSING) &&
+ 		    (do_clocal || (info->signals & SerialSignal_DCD)) ) {
+ 			break;
+		}
+
+		if (signal_pending(current)) {
+			retval = -ERESTARTSYS;
+			break;
+		}
+
+		DBGINFO(("%s block_til_ready wait\n", tty->driver->name));
+		schedule();
+	}
+
+	set_current_state(TASK_RUNNING);
+	remove_wait_queue(&info->open_wait, &wait);
+
+	if (extra_count)
+		info->count++;
+	info->blocked_open--;
+
+	if (!retval)
+		info->flags |= ASYNC_NORMAL_ACTIVE;
+
+	DBGINFO(("%s block_til_ready ready, rc=%d\n", tty->driver->name, retval));
+	return retval;
+}
+
+static int alloc_tmp_rbuf(struct slgt_info *info)
+{
+	info->tmp_rbuf = kmalloc(info->max_frame_size, GFP_KERNEL);
+	if (info->tmp_rbuf == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void free_tmp_rbuf(struct slgt_info *info)
+{
+	kfree(info->tmp_rbuf);
+	info->tmp_rbuf = NULL;
+}
+
+/*
+ * allocate DMA descriptor lists.
+ */
+static int alloc_desc(struct slgt_info *info)
+{
+	unsigned int i;
+	unsigned int pbufs;
+
+	/* allocate memory to hold descriptor lists */
+	info->bufs = pci_alloc_consistent(info->pdev, DESC_LIST_SIZE, &info->bufs_dma_addr);
+	if (info->bufs == NULL)
+		return -ENOMEM;
+
+	memset(info->bufs, 0, DESC_LIST_SIZE);
+
+	info->rbufs = (struct slgt_desc*)info->bufs;
+	info->tbufs = ((struct slgt_desc*)info->bufs) + info->rbuf_count;
+
+	pbufs = (unsigned int)info->bufs_dma_addr;
+
+	/*
+	 * Build circular lists of descriptors
+	 */
+
+	for (i=0; i < info->rbuf_count; i++) {
+		/* physical address of this descriptor */
+		info->rbufs[i].pdesc = pbufs + (i * sizeof(struct slgt_desc));
+
+		/* physical address of next descriptor */
+		if (i == info->rbuf_count - 1)
+			info->rbufs[i].next = cpu_to_le32(pbufs);
+		else
+			info->rbufs[i].next = cpu_to_le32(pbufs + ((i+1) * sizeof(struct slgt_desc)));
+		set_desc_count(info->rbufs[i], DMABUFSIZE);
+	}
+
+	for (i=0; i < info->tbuf_count; i++) {
+		/* physical address of this descriptor */
+		info->tbufs[i].pdesc = pbufs + ((info->rbuf_count + i) * sizeof(struct slgt_desc));
+
+		/* physical address of next descriptor */
+		if (i == info->tbuf_count - 1)
+			info->tbufs[i].next = cpu_to_le32(pbufs + info->rbuf_count * sizeof(struct slgt_desc));
+		else
+			info->tbufs[i].next = cpu_to_le32(pbufs + ((info->rbuf_count + i + 1) * sizeof(struct slgt_desc)));
+	}
+
+	return 0;
+}
+
+static void free_desc(struct slgt_info *info)
+{
+	if (info->bufs != NULL) {
+		pci_free_consistent(info->pdev, DESC_LIST_SIZE, info->bufs, info->bufs_dma_addr);
+		info->bufs  = NULL;
+		info->rbufs = NULL;
+		info->tbufs = NULL;
+	}
+}
+
+static int alloc_bufs(struct slgt_info *info, struct slgt_desc *bufs, int count)
+{
+	int i;
+	for (i=0; i < count; i++) {
+		if ((bufs[i].buf = pci_alloc_consistent(info->pdev, DMABUFSIZE, &bufs[i].buf_dma_addr)) == NULL)
+			return -ENOMEM;
+		bufs[i].pbuf  = cpu_to_le32((unsigned int)bufs[i].buf_dma_addr);
+	}
+	return 0;
+}
+
+static void free_bufs(struct slgt_info *info, struct slgt_desc *bufs, int count)
+{
+	int i;
+	for (i=0; i < count; i++) {
+		if (bufs[i].buf == NULL)
+			continue;
+		pci_free_consistent(info->pdev, DMABUFSIZE, bufs[i].buf, bufs[i].buf_dma_addr);
+		bufs[i].buf = NULL;
+	}
+}
+
+static int alloc_dma_bufs(struct slgt_info *info)
+{
+	info->rbuf_count = 32;
+	info->tbuf_count = 32;
+
+	if (alloc_desc(info) < 0 ||
+	    alloc_bufs(info, info->rbufs, info->rbuf_count) < 0 ||
+	    alloc_bufs(info, info->tbufs, info->tbuf_count) < 0 ||
+	    alloc_tmp_rbuf(info) < 0) {
+		DBGERR(("%s DMA buffer alloc fail\n", info->device_name));
+		return -ENOMEM;
+	}
+	reset_rbufs(info);
+	return 0;
+}
+
+static void free_dma_bufs(struct slgt_info *info)
+{
+	if (info->bufs) {
+		free_bufs(info, info->rbufs, info->rbuf_count);
+		free_bufs(info, info->tbufs, info->tbuf_count);
+		free_desc(info);
+	}
+	free_tmp_rbuf(info);
+}
+
+static int claim_resources(struct slgt_info *info)
+{
+	if (request_mem_region(info->phys_reg_addr, SLGT_REG_SIZE, "synclink_gt") == NULL) {
+		DBGERR(("%s reg addr conflict, addr=%08X\n",
+			info->device_name, info->phys_reg_addr));
+		info->init_error = DiagStatus_AddressConflict;
+		goto errout;
+	}
+	else
+		info->reg_addr_requested = 1;
+
+	info->reg_addr = ioremap(info->phys_reg_addr, PAGE_SIZE);
+	if (!info->reg_addr) {
+		DBGERR(("%s cant map device registers, addr=%08X\n",
+			info->device_name, info->phys_reg_addr));
+		info->init_error = DiagStatus_CantAssignPciResources;
+		goto errout;
+	}
+	info->reg_addr += info->reg_offset;
+	return 0;
+
+errout:
+	release_resources(info);
+	return -ENODEV;
+}
+
+static void release_resources(struct slgt_info *info)
+{
+	if (info->irq_requested) {
+		free_irq(info->irq_level, info);
+		info->irq_requested = 0;
+	}
+
+	if (info->reg_addr_requested) {
+		release_mem_region(info->phys_reg_addr, SLGT_REG_SIZE);
+		info->reg_addr_requested = 0;
+	}
+
+	if (info->reg_addr) {
+		iounmap(info->reg_addr - info->reg_offset);
+		info->reg_addr = NULL;
+	}
+}
+
+/* Add the specified device instance data structure to the
+ * global linked list of devices and increment the device count.
+ */
+static void add_device(struct slgt_info *info)
+{
+	char *devstr;
+
+	info->next_device = NULL;
+	info->line = slgt_device_count;
+	sprintf(info->device_name, "%s%d", tty_dev_prefix, info->line);
+
+	if (info->line < MAX_DEVICES) {
+		if (maxframe[info->line])
+			info->max_frame_size = maxframe[info->line];
+		info->dosyncppp = dosyncppp[info->line];
+	}
+
+	slgt_device_count++;
+
+	if (!slgt_device_list)
+		slgt_device_list = info;
+	else {
+		struct slgt_info *current_dev = slgt_device_list;
+		while(current_dev->next_device)
+			current_dev = current_dev->next_device;
+		current_dev->next_device = info;
+	}
+
+	if (info->max_frame_size < 4096)
+		info->max_frame_size = 4096;
+	else if (info->max_frame_size > 65535)
+		info->max_frame_size = 65535;
+
+	switch(info->pdev->device) {
+	case SYNCLINK_GT_DEVICE_ID:
+		devstr = "GT";
+		break;
+	case SYNCLINK_GT4_DEVICE_ID:
+		devstr = "GT4";
+		break;
+	case SYNCLINK_AC_DEVICE_ID:
+		devstr = "AC";
+		info->params.mode = MGSL_MODE_ASYNC;
+		break;
+	default:
+		devstr = "(unknown model)";
+	}
+	printk("SyncLink %s %s IO=%08x IRQ=%d MaxFrameSize=%u\n",
+		devstr, info->device_name, info->phys_reg_addr,
+		info->irq_level, info->max_frame_size);
+
+#ifdef CONFIG_HDLC
+	hdlcdev_init(info);
+#endif
+}
+
+/*
+ *  allocate device instance structure, return NULL on failure
+ */
+static struct slgt_info *alloc_dev(int adapter_num, int port_num, struct pci_dev *pdev)
+{
+	struct slgt_info *info;
+
+	info = kmalloc(sizeof(struct slgt_info), GFP_KERNEL);
+
+	if (!info) {
+		DBGERR(("%s device alloc failed adapter=%d port=%d\n",
+			driver_name, adapter_num, port_num));
+	} else {
+		memset(info, 0, sizeof(struct slgt_info));
+		info->magic = MGSL_MAGIC;
+		INIT_WORK(&info->task, bh_handler, info);
+		info->max_frame_size = 4096;
+		info->raw_rx_size = DMABUFSIZE;
+		info->close_delay = 5*HZ/10;
+		info->closing_wait = 30*HZ;
+		init_waitqueue_head(&info->open_wait);
+		init_waitqueue_head(&info->close_wait);
+		init_waitqueue_head(&info->status_event_wait_q);
+		init_waitqueue_head(&info->event_wait_q);
+		spin_lock_init(&info->netlock);
+		memcpy(&info->params,&default_params,sizeof(MGSL_PARAMS));
+		info->idle_mode = HDLC_TXIDLE_FLAGS;
+		info->adapter_num = adapter_num;
+		info->port_num = port_num;
+
+		init_timer(&info->tx_timer);
+		info->tx_timer.data = (unsigned long)info;
+		info->tx_timer.function = tx_timeout;
+
+		init_timer(&info->rx_timer);
+		info->rx_timer.data = (unsigned long)info;
+		info->rx_timer.function = rx_timeout;
+
+		/* Copy configuration info to device instance data */
+		info->pdev = pdev;
+		info->irq_level = pdev->irq;
+		info->phys_reg_addr = pci_resource_start(pdev,0);
+
+		/* veremap works on page boundaries
+		 * map full page starting at the page boundary
+		 */
+		info->reg_offset    = info->phys_reg_addr & (PAGE_SIZE-1);
+		info->phys_reg_addr &= ~(PAGE_SIZE-1);
+
+		info->bus_type = MGSL_BUS_TYPE_PCI;
+		info->irq_flags = SA_SHIRQ;
+
+		info->init_error = -1; /* assume error, set to 0 on successful init */
+	}
+
+	return info;
+}
+
+static void device_init(int adapter_num, struct pci_dev *pdev)
+{
+	struct slgt_info *port_array[SLGT_MAX_PORTS];
+	int i;
+	int port_count = 1;
+
+	if (pdev->device == SYNCLINK_GT4_DEVICE_ID)
+		port_count = 4;
+
+	/* allocate device instances for all ports */
+	for (i=0; i < port_count; ++i) {
+		port_array[i] = alloc_dev(adapter_num, i, pdev);
+		if (port_array[i] == NULL) {
+			for (--i; i >= 0; --i)
+				kfree(port_array[i]);
+			return;
+		}
+	}
+
+	/* give copy of port_array to all ports and add to device list  */
+	for (i=0; i < port_count; ++i) {
+		memcpy(port_array[i]->port_array, port_array, sizeof(port_array));
+		add_device(port_array[i]);
+		port_array[i]->port_count = port_count;
+		spin_lock_init(&port_array[i]->lock);
+	}
+
+	/* Allocate and claim adapter resources */
+	if (!claim_resources(port_array[0])) {
+
+		alloc_dma_bufs(port_array[0]);
+
+		/* copy resource information from first port to others */
+		for (i = 1; i < port_count; ++i) {
+			port_array[i]->lock      = port_array[0]->lock;
+			port_array[i]->irq_level = port_array[0]->irq_level;
+			port_array[i]->reg_addr  = port_array[0]->reg_addr;
+			alloc_dma_bufs(port_array[i]);
+		}
+
+		if (request_irq(port_array[0]->irq_level,
+					slgt_interrupt,
+					port_array[0]->irq_flags,
+					port_array[0]->device_name,
+					port_array[0]) < 0) {
+			DBGERR(("%s request_irq failed IRQ=%d\n",
+				port_array[0]->device_name,
+				port_array[0]->irq_level));
+		} else {
+			port_array[0]->irq_requested = 1;
+			adapter_test(port_array[0]);
+			for (i=1 ; i < port_count ; i++)
+				port_array[i]->init_error = port_array[0]->init_error;
+		}
+	}
+}
+
+static int __devinit init_one(struct pci_dev *dev,
+			      const struct pci_device_id *ent)
+{
+	if (pci_enable_device(dev)) {
+		printk("error enabling pci device %p\n", dev);
+		return -EIO;
+	}
+	pci_set_master(dev);
+	device_init(slgt_device_count, dev);
+	return 0;
+}
+
+static void __devexit remove_one(struct pci_dev *dev)
+{
+}
+
+static struct tty_operations ops = {
+	.open = open,
+	.close = close,
+	.write = write,
+	.put_char = put_char,
+	.flush_chars = flush_chars,
+	.write_room = write_room,
+	.chars_in_buffer = chars_in_buffer,
+	.flush_buffer = flush_buffer,
+	.ioctl = ioctl,
+	.throttle = throttle,
+	.unthrottle = unthrottle,
+	.send_xchar = send_xchar,
+	.break_ctl = set_break,
+	.wait_until_sent = wait_until_sent,
+ 	.read_proc = read_proc,
+	.set_termios = set_termios,
+	.stop = tx_hold,
+	.start = tx_release,
+	.hangup = hangup,
+	.tiocmget = tiocmget,
+	.tiocmset = tiocmset,
+};
+
+static void slgt_cleanup(void)
+{
+	int rc;
+	struct slgt_info *info;
+	struct slgt_info *tmp;
+
+	printk("unload %s %s\n", driver_name, driver_version);
+
+	if (serial_driver) {
+		if ((rc = tty_unregister_driver(serial_driver)))
+			DBGERR(("tty_unregister_driver error=%d\n", rc));
+		put_tty_driver(serial_driver);
+	}
+
+	/* reset devices */
+	info = slgt_device_list;
+	while(info) {
+		reset_port(info);
+		info = info->next_device;
+	}
+
+	/* release devices */
+	info = slgt_device_list;
+	while(info) {
+#ifdef CONFIG_HDLC
+		hdlcdev_exit(info);
+#endif
+		free_dma_bufs(info);
+		free_tmp_rbuf(info);
+		if (info->port_num == 0)
+			release_resources(info);
+		tmp = info;
+		info = info->next_device;
+		kfree(tmp);
+	}
+
+	if (pci_registered)
+		pci_unregister_driver(&pci_driver);
+}
+
+/*
+ *  Driver initialization entry point.
+ */
+static int __init slgt_init(void)
+{
+	int rc;
+
+ 	printk("%s %s\n", driver_name, driver_version);
+
+	slgt_device_count = 0;
+	if ((rc = pci_register_driver(&pci_driver)) < 0) {
+		printk("%s pci_register_driver error=%d\n", driver_name, rc);
+		return rc;
+	}
+	pci_registered = 1;
+
+	if (!slgt_device_list) {
+		printk("%s no devices found\n",driver_name);
+		return -ENODEV;
+	}
+
+	serial_driver = alloc_tty_driver(MAX_DEVICES);
+	if (!serial_driver) {
+		rc = -ENOMEM;
+		goto error;
+	}
+
+	/* Initialize the tty_driver structure */
+
+	serial_driver->owner = THIS_MODULE;
+	serial_driver->driver_name = tty_driver_name;
+	serial_driver->name = tty_dev_prefix;
+	serial_driver->major = ttymajor;
+	serial_driver->minor_start = 64;
+	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
+	serial_driver->subtype = SERIAL_TYPE_NORMAL;
+	serial_driver->init_termios = tty_std_termios;
+	serial_driver->init_termios.c_cflag =
+		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+	serial_driver->flags = TTY_DRIVER_REAL_RAW;
+	tty_set_operations(serial_driver, &ops);
+	if ((rc = tty_register_driver(serial_driver)) < 0) {
+		DBGERR(("%s can't register serial driver\n", driver_name));
+		put_tty_driver(serial_driver);
+		serial_driver = NULL;
+		goto error;
+	}
+
+ 	printk("%s %s, tty major#%d\n",
+		driver_name, driver_version,
+		serial_driver->major);
+
+	return 0;
+
+error:
+	slgt_cleanup();
+	return rc;
+}
+
+static void __exit slgt_exit(void)
+{
+	slgt_cleanup();
+}
+
+module_init(slgt_init);
+module_exit(slgt_exit);
+
+/*
+ * register access routines
+ */
+
+#define CALC_REGADDR() \
+	unsigned long reg_addr = ((unsigned long)info->reg_addr) + addr; \
+	if (addr >= 0x80) \
+		reg_addr += (info->port_num) * 32;
+
+static __u8 rd_reg8(struct slgt_info *info, unsigned int addr)
+{
+	CALC_REGADDR();
+	return readb((void __iomem *)reg_addr);
+}
+
+static void wr_reg8(struct slgt_info *info, unsigned int addr, __u8 value)
+{
+	CALC_REGADDR();
+	writeb(value, (void __iomem *)reg_addr);
+}
+
+static __u16 rd_reg16(struct slgt_info *info, unsigned int addr)
+{
+	CALC_REGADDR();
+	return readw((void __iomem *)reg_addr);
+}
+
+static void wr_reg16(struct slgt_info *info, unsigned int addr, __u16 value)
+{
+	CALC_REGADDR();
+	writew(value, (void __iomem *)reg_addr);
+}
+
+static __u32 rd_reg32(struct slgt_info *info, unsigned int addr)
+{
+	CALC_REGADDR();
+	return readl((void __iomem *)reg_addr);
+}
+
+static void wr_reg32(struct slgt_info *info, unsigned int addr, __u32 value)
+{
+	CALC_REGADDR();
+	writel(value, (void __iomem *)reg_addr);
+}
+
+static void rdma_reset(struct slgt_info *info)
+{
+	unsigned int i;
+
+	/* set reset bit */
+	wr_reg32(info, RDCSR, BIT1);
+
+	/* wait for enable bit cleared */
+	for(i=0 ; i < 1000 ; i++)
+		if (!(rd_reg32(info, RDCSR) & BIT0))
+			break;
+}
+
+static void tdma_reset(struct slgt_info *info)
+{
+	unsigned int i;
+
+	/* set reset bit */
+	wr_reg32(info, TDCSR, BIT1);
+
+	/* wait for enable bit cleared */
+	for(i=0 ; i < 1000 ; i++)
+		if (!(rd_reg32(info, TDCSR) & BIT0))
+			break;
+}
+
+/*
+ * enable internal loopback
+ * TxCLK and RxCLK are generated from BRG
+ * and TxD is looped back to RxD internally.
+ */
+static void enable_loopback(struct slgt_info *info)
+{
+	/* SCR (serial control) BIT2=looopback enable */
+	wr_reg16(info, SCR, (unsigned short)(rd_reg16(info, SCR) | BIT2));
+
+	if (info->params.mode != MGSL_MODE_ASYNC) {
+		/* CCR (clock control)
+		 * 07..05  tx clock source (010 = BRG)
+		 * 04..02  rx clock source (010 = BRG)
+		 * 01      auxclk enable   (0 = disable)
+		 * 00      BRG enable      (1 = enable)
+		 *
+		 * 0100 1001
+		 */
+		wr_reg8(info, CCR, 0x49);
+
+		/* set speed if available, otherwise use default */
+		if (info->params.clock_speed)
+			set_rate(info, info->params.clock_speed);
+		else
+			set_rate(info, 3686400);
+	}
+}
+
+/*
+ *  set baud rate generator to specified rate
+ */
+static void set_rate(struct slgt_info *info, u32 rate)
+{
+	unsigned int div;
+	static unsigned int osc = 14745600;
+
+	/* div = osc/rate - 1
+	 *
+	 * Round div up if osc/rate is not integer to
+	 * force to next slowest rate.
+	 */
+
+	if (rate) {
+		div = osc/rate;
+		if (!(osc % rate) && div)
+			div--;
+		wr_reg16(info, BDR, (unsigned short)div);
+	}
+}
+
+static void rx_stop(struct slgt_info *info)
+{
+	unsigned short val;
+
+	/* disable and reset receiver */
+	val = rd_reg16(info, RCR) & ~BIT1;          /* clear enable bit */
+	wr_reg16(info, RCR, (unsigned short)(val | BIT2)); /* set reset bit */
+	wr_reg16(info, RCR, val);                  /* clear reset bit */
+
+	slgt_irq_off(info, IRQ_RXOVER + IRQ_RXDATA + IRQ_RXIDLE);
+
+	/* clear pending rx interrupts */
+	wr_reg16(info, SSR, IRQ_RXIDLE + IRQ_RXOVER);
+
+	rdma_reset(info);
+
+	info->rx_enabled = 0;
+	info->rx_restart = 0;
+}
+
+static void rx_start(struct slgt_info *info)
+{
+	unsigned short val;
+
+	slgt_irq_off(info, IRQ_RXOVER + IRQ_RXDATA);
+
+	/* clear pending rx overrun IRQ */
+	wr_reg16(info, SSR, IRQ_RXOVER);
+
+	/* reset and disable receiver */
+	val = rd_reg16(info, RCR) & ~BIT1; /* clear enable bit */
+	wr_reg16(info, RCR, (unsigned short)(val | BIT2)); /* set reset bit */
+	wr_reg16(info, RCR, val);                  /* clear reset bit */
+
+	rdma_reset(info);
+	reset_rbufs(info);
+
+	/* set 1st descriptor address */
+	wr_reg32(info, RDDAR, info->rbufs[0].pdesc);
+
+	if (info->params.mode != MGSL_MODE_ASYNC) {
+		/* enable rx DMA and DMA interrupt */
+		wr_reg32(info, RDCSR, (BIT2 + BIT0));
+	} else {
+		/* enable saving of rx status, rx DMA and DMA interrupt */
+		wr_reg32(info, RDCSR, (BIT6 + BIT2 + BIT0));
+	}
+
+	slgt_irq_on(info, IRQ_RXOVER);
+
+	/* enable receiver */
+	wr_reg16(info, RCR, (unsigned short)(rd_reg16(info, RCR) | BIT1));
+
+	info->rx_restart = 0;
+	info->rx_enabled = 1;
+}
+
+static void tx_start(struct slgt_info *info)
+{
+	if (!info->tx_enabled) {
+		wr_reg16(info, TCR,
+			(unsigned short)(rd_reg16(info, TCR) | BIT1));
+		info->tx_enabled = TRUE;
+	}
+
+	if (info->tx_count) {
+		info->drop_rts_on_tx_done = 0;
+
+		if (info->params.mode != MGSL_MODE_ASYNC) {
+			if (info->params.flags & HDLC_FLAG_AUTO_RTS) {
+				get_signals(info);
+				if (!(info->signals & SerialSignal_RTS)) {
+					info->signals |= SerialSignal_RTS;
+					set_signals(info);
+					info->drop_rts_on_tx_done = 1;
+				}
+			}
+
+			slgt_irq_off(info, IRQ_TXDATA);
+			slgt_irq_on(info, IRQ_TXUNDER + IRQ_TXIDLE);
+			/* clear tx idle and underrun status bits */
+			wr_reg16(info, SSR, (unsigned short)(IRQ_TXIDLE + IRQ_TXUNDER));
+
+			if (!(rd_reg32(info, TDCSR) & BIT0)) {
+				/* tx DMA stopped, restart tx DMA */
+				tdma_reset(info);
+				/* set 1st descriptor address */
+				wr_reg32(info, TDDAR, info->tbufs[info->tbuf_start].pdesc);
+				if (info->params.mode == MGSL_MODE_RAW)
+					wr_reg32(info, TDCSR, BIT2 + BIT0); /* IRQ + DMA enable */
+				else
+					wr_reg32(info, TDCSR, BIT0); /* DMA enable */
+			}
+
+			if (info->params.mode != MGSL_MODE_RAW) {
+				info->tx_timer.expires = jiffies + msecs_to_jiffies(5000);
+				add_timer(&info->tx_timer);
+			}
+		} else {
+			tdma_reset(info);
+			/* set 1st descriptor address */
+			wr_reg32(info, TDDAR, info->tbufs[info->tbuf_start].pdesc);
+
+			slgt_irq_off(info, IRQ_TXDATA);
+			slgt_irq_on(info, IRQ_TXIDLE);
+			/* clear tx idle status bit */
+			wr_reg16(info, SSR, IRQ_TXIDLE);
+
+			/* enable tx DMA */
+			wr_reg32(info, TDCSR, BIT0);
+		}
+
+		info->tx_active = 1;
+	}
+}
+
+static void tx_stop(struct slgt_info *info)
+{
+	unsigned short val;
+
+	del_timer(&info->tx_timer);
+
+	tdma_reset(info);
+
+	/* reset and disable transmitter */
+	val = rd_reg16(info, TCR) & ~BIT1;          /* clear enable bit */
+	wr_reg16(info, TCR, (unsigned short)(val | BIT2)); /* set reset bit */
+	wr_reg16(info, TCR, val);                  /* clear reset */
+
+	slgt_irq_off(info, IRQ_TXDATA + IRQ_TXIDLE + IRQ_TXUNDER);
+
+	/* clear tx idle and underrun status bit */
+	wr_reg16(info, SSR, (unsigned short)(IRQ_TXIDLE + IRQ_TXUNDER));
+
+	reset_tbufs(info);
+
+	info->tx_enabled = 0;
+	info->tx_active  = 0;
+}
+
+static void reset_port(struct slgt_info *info)
+{
+	if (!info->reg_addr)
+		return;
+
+	tx_stop(info);
+	rx_stop(info);
+
+	info->signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
+	set_signals(info);
+
+	slgt_irq_off(info, IRQ_ALL | IRQ_MASTER);
+}
+
+static void reset_adapter(struct slgt_info *info)
+{
+	int i;
+	for (i=0; i < info->port_count; ++i) {
+		if (info->port_array[i])
+			reset_port(info->port_array[i]);
+	}
+}
+
+static void async_mode(struct slgt_info *info)
+{
+  	unsigned short val;
+
+	slgt_irq_off(info, IRQ_ALL | IRQ_MASTER);
+	tx_stop(info);
+	rx_stop(info);
+
+	/* TCR (tx control)
+	 *
+	 * 15..13  mode, 010=async
+	 * 12..10  encoding, 000=NRZ
+	 * 09      parity enable
+	 * 08      1=odd parity, 0=even parity
+	 * 07      1=RTS driver control
+	 * 06      1=break enable
+	 * 05..04  character length
+	 *         00=5 bits
+	 *         01=6 bits
+	 *         10=7 bits
+	 *         11=8 bits
+	 * 03      0=1 stop bit, 1=2 stop bits
+	 * 02      reset
+	 * 01      enable
+	 * 00      auto-CTS enable
+	 */
+	val = 0x4000;
+
+	if (info->if_mode & MGSL_INTERFACE_RTS_EN)
+		val |= BIT7;
+
+	if (info->params.parity != ASYNC_PARITY_NONE) {
+		val |= BIT9;
+		if (info->params.parity == ASYNC_PARITY_ODD)
+			val |= BIT8;
+	}
+
+	switch (info->params.data_bits)
+	{
+	case 6: val |= BIT4; break;
+	case 7: val |= BIT5; break;
+	case 8: val |= BIT5 + BIT4; break;
+	}
+
+	if (info->params.stop_bits != 1)
+		val |= BIT3;
+
+	if (info->params.flags & HDLC_FLAG_AUTO_CTS)
+		val |= BIT0;
+
+	wr_reg16(info, TCR, val);
+
+	/* RCR (rx control)
+	 *
+	 * 15..13  mode, 010=async
+	 * 12..10  encoding, 000=NRZ
+	 * 09      parity enable
+	 * 08      1=odd parity, 0=even parity
+	 * 07..06  reserved, must be 0
+	 * 05..04  character length
+	 *         00=5 bits
+	 *         01=6 bits
+	 *         10=7 bits
+	 *         11=8 bits
+	 * 03      reserved, must be zero
+	 * 02      reset
+	 * 01      enable
+	 * 00      auto-DCD enable
+	 */
+	val = 0x4000;
+
+	if (info->params.parity != ASYNC_PARITY_NONE) {
+		val |= BIT9;
+		if (info->params.parity == ASYNC_PARITY_ODD)
+			val |= BIT8;
+	}
+
+	switch (info->params.data_bits)
+	{
+	case 6: val |= BIT4; break;
+	case 7: val |= BIT5; break;
+	case 8: val |= BIT5 + BIT4; break;
+	}
+
+	if (info->params.flags & HDLC_FLAG_AUTO_DCD)
+		val |= BIT0;
+
+	wr_reg16(info, RCR, val);
+
+	/* CCR (clock control)
+	 *
+	 * 07..05  011 = tx clock source is BRG/16
+	 * 04..02  010 = rx clock source is BRG
+	 * 01      0 = auxclk disabled
+	 * 00      1 = BRG enabled
+	 *
+	 * 0110 1001
+	 */
+	wr_reg8(info, CCR, 0x69);
+
+	msc_set_vcr(info);
+
+	tx_set_idle(info);
+
+	/* SCR (serial control)
+	 *
+	 * 15  1=tx req on FIFO half empty
+	 * 14  1=rx req on FIFO half full
+	 * 13  tx data  IRQ enable
+	 * 12  tx idle  IRQ enable
+	 * 11  rx break on IRQ enable
+	 * 10  rx data  IRQ enable
+	 * 09  rx break off IRQ enable
+	 * 08  overrun  IRQ enable
+	 * 07  DSR      IRQ enable
+	 * 06  CTS      IRQ enable
+	 * 05  DCD      IRQ enable
+	 * 04  RI       IRQ enable
+	 * 03  reserved, must be zero
+	 * 02  1=txd->rxd internal loopback enable
+	 * 01  reserved, must be zero
+	 * 00  1=master IRQ enable
+	 */
+	val = BIT15 + BIT14 + BIT0;
+	wr_reg16(info, SCR, val);
+
+	slgt_irq_on(info, IRQ_RXBREAK | IRQ_RXOVER);
+
+	set_rate(info, info->params.data_rate * 16);
+
+	if (info->params.loopback)
+		enable_loopback(info);
+}
+
+static void hdlc_mode(struct slgt_info *info)
+{
+	unsigned short val;
+
+	slgt_irq_off(info, IRQ_ALL | IRQ_MASTER);
+	tx_stop(info);
+	rx_stop(info);
+
+	/* TCR (tx control)
+	 *
+	 * 15..13  mode, 000=HDLC 001=raw sync
+	 * 12..10  encoding
+	 * 09      CRC enable
+	 * 08      CRC32
+	 * 07      1=RTS driver control
+	 * 06      preamble enable
+	 * 05..04  preamble length
+	 * 03      share open/close flag
+	 * 02      reset
+	 * 01      enable
+	 * 00      auto-CTS enable
+	 */
+	val = 0;
+
+	if (info->params.mode == MGSL_MODE_RAW)
+		val |= BIT13;
+	if (info->if_mode & MGSL_INTERFACE_RTS_EN)
+		val |= BIT7;
+
+	switch(info->params.encoding)
+	{
+	case HDLC_ENCODING_NRZB:          val |= BIT10; break;
+	case HDLC_ENCODING_NRZI_MARK:     val |= BIT11; break;
+	case HDLC_ENCODING_NRZI:          val |= BIT11 + BIT10; break;
+	case HDLC_ENCODING_BIPHASE_MARK:  val |= BIT12; break;
+	case HDLC_ENCODING_BIPHASE_SPACE: val |= BIT12 + BIT10; break;
+	case HDLC_ENCODING_BIPHASE_LEVEL: val |= BIT12 + BIT11; break;
+	case HDLC_ENCODING_DIFF_BIPHASE_LEVEL: val |= BIT12 + BIT11 + BIT10; break;
+	}
+
+	switch (info->params.crc_type)
+	{
+	case HDLC_CRC_16_CCITT: val |= BIT9; break;
+	case HDLC_CRC_32_CCITT: val |= BIT9 + BIT8; break;
+	}
+
+	if (info->params.preamble != HDLC_PREAMBLE_PATTERN_NONE)
+		val |= BIT6;
+
+	switch (info->params.preamble_length)
+	{
+	case HDLC_PREAMBLE_LENGTH_16BITS: val |= BIT5; break;
+	case HDLC_PREAMBLE_LENGTH_32BITS: val |= BIT4; break;
+	case HDLC_PREAMBLE_LENGTH_64BITS: val |= BIT5 + BIT4; break;
+	}
+
+	if (info->params.flags & HDLC_FLAG_AUTO_CTS)
+		val |= BIT0;
+
+	wr_reg16(info, TCR, val);
+
+	/* TPR (transmit preamble) */
+
+	switch (info->params.preamble)
+	{
+	case HDLC_PREAMBLE_PATTERN_FLAGS: val = 0x7e; break;
+	case HDLC_PREAMBLE_PATTERN_ONES:  val = 0xff; break;
+	case HDLC_PREAMBLE_PATTERN_ZEROS: val = 0x00; break;
+	case HDLC_PREAMBLE_PATTERN_10:    val = 0x55; break;
+	case HDLC_PREAMBLE_PATTERN_01:    val = 0xaa; break;
+	default:                          val = 0x7e; break;
+	}
+	wr_reg8(info, TPR, (unsigned char)val);
+
+	/* RCR (rx control)
+	 *
+	 * 15..13  mode, 000=HDLC 001=raw sync
+	 * 12..10  encoding
+	 * 09      CRC enable
+	 * 08      CRC32
+	 * 07..03  reserved, must be 0
+	 * 02      reset
+	 * 01      enable
+	 * 00      auto-DCD enable
+	 */
+	val = 0;
+
+	if (info->params.mode == MGSL_MODE_RAW)
+		val |= BIT13;
+
+	switch(info->params.encoding)
+	{
+	case HDLC_ENCODING_NRZB:          val |= BIT10; break;
+	case HDLC_ENCODING_NRZI_MARK:     val |= BIT11; break;
+	case HDLC_ENCODING_NRZI:          val |= BIT11 + BIT10; break;
+	case HDLC_ENCODING_BIPHASE_MARK:  val |= BIT12; break;
+	case HDLC_ENCODING_BIPHASE_SPACE: val |= BIT12 + BIT10; break;
+	case HDLC_ENCODING_BIPHASE_LEVEL: val |= BIT12 + BIT11; break;
+	case HDLC_ENCODING_DIFF_BIPHASE_LEVEL: val |= BIT12 + BIT11 + BIT10; break;
+	}
+
+	switch (info->params.crc_type)
+	{
+	case HDLC_CRC_16_CCITT: val |= BIT9; break;
+	case HDLC_CRC_32_CCITT: val |= BIT9 + BIT8; break;
+	}
+
+	if (info->params.flags & HDLC_FLAG_AUTO_DCD)
+		val |= BIT0;
+
+	wr_reg16(info, RCR, val);
+
+	/* CCR (clock control)
+	 *
+	 * 07..05  tx clock source
+	 * 04..02  rx clock source
+	 * 01      auxclk enable
+	 * 00      BRG enable
+	 */
+	val = 0;
+
+	if (info->params.flags & HDLC_FLAG_TXC_BRG)
+	{
+		// when RxC source is DPLL, BRG generates 16X DPLL
+		// reference clock, so take TxC from BRG/16 to get
+		// transmit clock at actual data rate
+		if (info->params.flags & HDLC_FLAG_RXC_DPLL)
+			val |= BIT6 + BIT5;	/* 011, txclk = BRG/16 */
+		else
+			val |= BIT6;	/* 010, txclk = BRG */
+	}
+	else if (info->params.flags & HDLC_FLAG_TXC_DPLL)
+		val |= BIT7;	/* 100, txclk = DPLL Input */
+	else if (info->params.flags & HDLC_FLAG_TXC_RXCPIN)
+		val |= BIT5;	/* 001, txclk = RXC Input */
+
+	if (info->params.flags & HDLC_FLAG_RXC_BRG)
+		val |= BIT3;	/* 010, rxclk = BRG */
+	else if (info->params.flags & HDLC_FLAG_RXC_DPLL)
+		val |= BIT4;	/* 100, rxclk = DPLL */
+	else if (info->params.flags & HDLC_FLAG_RXC_TXCPIN)
+		val |= BIT2;	/* 001, rxclk = TXC Input */
+
+	if (info->params.clock_speed)
+		val |= BIT1 + BIT0;
+
+	wr_reg8(info, CCR, (unsigned char)val);
+
+	if (info->params.flags & (HDLC_FLAG_TXC_DPLL + HDLC_FLAG_RXC_DPLL))
+	{
+		// program DPLL mode
+		switch(info->params.encoding)
+		{
+		case HDLC_ENCODING_BIPHASE_MARK:
+		case HDLC_ENCODING_BIPHASE_SPACE:
+			val = BIT7; break;
+		case HDLC_ENCODING_BIPHASE_LEVEL:
+		case HDLC_ENCODING_DIFF_BIPHASE_LEVEL:
+			val = BIT7 + BIT6; break;
+		default: val = BIT6;	// NRZ encodings
+		}
+		wr_reg16(info, RCR, (unsigned short)(rd_reg16(info, RCR) | val));
+
+		// DPLL requires a 16X reference clock from BRG
+		set_rate(info, info->params.clock_speed * 16);
+	}
+	else
+		set_rate(info, info->params.clock_speed);
+
+	tx_set_idle(info);
+
+	msc_set_vcr(info);
+
+	/* SCR (serial control)
+	 *
+	 * 15  1=tx req on FIFO half empty
+	 * 14  1=rx req on FIFO half full
+	 * 13  tx data  IRQ enable
+	 * 12  tx idle  IRQ enable
+	 * 11  underrun IRQ enable
+	 * 10  rx data  IRQ enable
+	 * 09  rx idle  IRQ enable
+	 * 08  overrun  IRQ enable
+	 * 07  DSR      IRQ enable
+	 * 06  CTS      IRQ enable
+	 * 05  DCD      IRQ enable
+	 * 04  RI       IRQ enable
+	 * 03  reserved, must be zero
+	 * 02  1=txd->rxd internal loopback enable
+	 * 01  reserved, must be zero
+	 * 00  1=master IRQ enable
+	 */
+	wr_reg16(info, SCR, BIT15 + BIT14 + BIT0);
+
+	if (info->params.loopback)
+		enable_loopback(info);
+}
+
+/*
+ *  set transmit idle mode
+ */
+static void tx_set_idle(struct slgt_info *info)
+{
+	unsigned char val = 0xff;
+
+	switch(info->idle_mode)
+	{
+	case HDLC_TXIDLE_FLAGS:          val = 0x7e; break;
+	case HDLC_TXIDLE_ALT_ZEROS_ONES: val = 0xaa; break;
+	case HDLC_TXIDLE_ZEROS:          val = 0x00; break;
+	case HDLC_TXIDLE_ONES:           val = 0xff; break;
+	case HDLC_TXIDLE_ALT_MARK_SPACE: val = 0xaa; break;
+	case HDLC_TXIDLE_SPACE:          val = 0x00; break;
+	case HDLC_TXIDLE_MARK:           val = 0xff; break;
+	}
+
+	wr_reg8(info, TIR, val);
+}
+
+/*
+ * get state of V24 status (input) signals
+ */
+static void get_signals(struct slgt_info *info)
+{
+	unsigned short status = rd_reg16(info, SSR);
+
+	/* clear all serial signals except DTR and RTS */
+	info->signals &= SerialSignal_DTR + SerialSignal_RTS;
+
+	if (status & BIT3)
+		info->signals |= SerialSignal_DSR;
+	if (status & BIT2)
+		info->signals |= SerialSignal_CTS;
+	if (status & BIT1)
+		info->signals |= SerialSignal_DCD;
+	if (status & BIT0)
+		info->signals |= SerialSignal_RI;
+}
+
+/*
+ * set V.24 Control Register based on current configuration
+ */
+static void msc_set_vcr(struct slgt_info *info)
+{
+	unsigned char val = 0;
+
+	/* VCR (V.24 control)
+	 *
+	 * 07..04  serial IF select
+	 * 03      DTR
+	 * 02      RTS
+	 * 01      LL
+	 * 00      RL
+	 */
+
+	switch(info->if_mode & MGSL_INTERFACE_MASK)
+	{
+	case MGSL_INTERFACE_RS232:
+		val |= BIT5; /* 0010 */
+		break;
+	case MGSL_INTERFACE_V35:
+		val |= BIT7 + BIT6 + BIT5; /* 1110 */
+		break;
+	case MGSL_INTERFACE_RS422:
+		val |= BIT6; /* 0100 */
+		break;
+	}
+
+	if (info->signals & SerialSignal_DTR)
+		val |= BIT3;
+	if (info->signals & SerialSignal_RTS)
+		val |= BIT2;
+	if (info->if_mode & MGSL_INTERFACE_LL)
+		val |= BIT1;
+	if (info->if_mode & MGSL_INTERFACE_RL)
+		val |= BIT0;
+	wr_reg8(info, VCR, val);
+}
+
+/*
+ * set state of V24 control (output) signals
+ */
+static void set_signals(struct slgt_info *info)
+{
+	unsigned char val = rd_reg8(info, VCR);
+	if (info->signals & SerialSignal_DTR)
+		val |= BIT3;
+	else
+		val &= ~BIT3;
+	if (info->signals & SerialSignal_RTS)
+		val |= BIT2;
+	else
+		val &= ~BIT2;
+	wr_reg8(info, VCR, val);
+}
+
+/*
+ * free range of receive DMA buffers (i to last)
+ */
+static void free_rbufs(struct slgt_info *info, unsigned int i, unsigned int last)
+{
+	int done = 0;
+
+	while(!done) {
+		/* reset current buffer for reuse */
+		info->rbufs[i].status = 0;
+		if (info->params.mode == MGSL_MODE_RAW)
+			set_desc_count(info->rbufs[i], info->raw_rx_size);
+		else
+			set_desc_count(info->rbufs[i], DMABUFSIZE);
+
+		if (i == last)
+			done = 1;
+		if (++i == info->rbuf_count)
+			i = 0;
+	}
+	info->rbuf_current = i;
+}
+
+/*
+ * mark all receive DMA buffers as free
+ */
+static void reset_rbufs(struct slgt_info *info)
+{
+	free_rbufs(info, 0, info->rbuf_count - 1);
+}
+
+/*
+ * pass receive HDLC frame to upper layer
+ *
+ * return 1 if frame available, otherwise 0
+ */
+static int rx_get_frame(struct slgt_info *info)
+{
+	unsigned int start, end;
+	unsigned short status;
+	unsigned int framesize = 0;
+	int rc = 0;
+	unsigned long flags;
+	struct tty_struct *tty = info->tty;
+	unsigned char addr_field = 0xff;
+
+check_again:
+
+	framesize = 0;
+	addr_field = 0xff;
+	start = end = info->rbuf_current;
+
+	for (;;) {
+		if (!desc_complete(info->rbufs[end]))
+			goto cleanup;
+
+		if (framesize == 0 && info->params.addr_filter != 0xff)
+			addr_field = info->rbufs[end].buf[0];
+
+		framesize += desc_count(info->rbufs[end]);
+
+		if (desc_eof(info->rbufs[end]))
+			break;
+
+		if (++end == info->rbuf_count)
+			end = 0;
+
+		if (end == info->rbuf_current) {
+			if (info->rx_enabled){
+				spin_lock_irqsave(&info->lock,flags);
+				rx_start(info);
+				spin_unlock_irqrestore(&info->lock,flags);
+			}
+			goto cleanup;
+		}
+	}
+
+	/* status
+	 *
+	 * 15      buffer complete
+	 * 14..06  reserved
+	 * 05..04  residue
+	 * 02      eof (end of frame)
+	 * 01      CRC error
+	 * 00      abort
+	 */
+	status = desc_status(info->rbufs[end]);
+
+	/* ignore CRC bit if not using CRC (bit is undefined) */
+	if (info->params.crc_type == HDLC_CRC_NONE)
+		status &= ~BIT1;
+
+	if (framesize == 0 ||
+		 (addr_field != 0xff && addr_field != info->params.addr_filter)) {
+		free_rbufs(info, start, end);
+		goto check_again;
+	}
+
+	if (framesize < 2 || status & (BIT1+BIT0)) {
+		if (framesize < 2 || (status & BIT0))
+			info->icount.rxshort++;
+		else
+			info->icount.rxcrc++;
+		framesize = 0;
+
+#ifdef CONFIG_HDLC
+		{
+			struct net_device_stats *stats = hdlc_stats(info->netdev);
+			stats->rx_errors++;
+			stats->rx_frame_errors++;
+		}
+#endif
+	} else {
+		/* adjust frame size for CRC, if any */
+		if (info->params.crc_type == HDLC_CRC_16_CCITT)
+			framesize -= 2;
+		else if (info->params.crc_type == HDLC_CRC_32_CCITT)
+			framesize -= 4;
+	}
+
+	DBGBH(("%s rx frame status=%04X size=%d\n",
+		info->device_name, status, framesize));
+	DBGDATA(info, info->rbufs[start].buf, min_t(int, framesize, DMABUFSIZE), "rx");
+
+	if (framesize) {
+		if (framesize > info->max_frame_size)
+			info->icount.rxlong++;
+		else {
+			/* copy dma buffer(s) to contiguous temp buffer */
+			int copy_count = framesize;
+			int i = start;
+			unsigned char *p = info->tmp_rbuf;
+			info->tmp_rbuf_count = framesize;
+
+			info->icount.rxok++;
+
+			while(copy_count) {
+				int partial_count = min(copy_count, DMABUFSIZE);
+				memcpy(p, info->rbufs[i].buf, partial_count);
+				p += partial_count;
+				copy_count -= partial_count;
+				if (++i == info->rbuf_count)
+					i = 0;
+			}
+
+#ifdef CONFIG_HDLC
+			if (info->netcount)
+				hdlcdev_rx(info,info->tmp_rbuf, framesize);
+			else
+#endif
+				ldisc_receive_buf(tty, info->tmp_rbuf, info->flag_buf, framesize);
+		}
+	}
+	free_rbufs(info, start, end);
+	rc = 1;
+
+cleanup:
+	return rc;
+}
+
+/*
+ * pass receive buffer (RAW synchronous mode) to tty layer
+ * return 1 if buffer available, otherwise 0
+ */
+static int rx_get_buf(struct slgt_info *info)
+{
+	unsigned int i = info->rbuf_current;
+
+	if (!desc_complete(info->rbufs[i]))
+		return 0;
+	DBGDATA(info, info->rbufs[i].buf, desc_count(info->rbufs[i]), "rx");
+	DBGINFO(("rx_get_buf size=%d\n", desc_count(info->rbufs[i])));
+	ldisc_receive_buf(info->tty, info->rbufs[i].buf,
+			  info->flag_buf, desc_count(info->rbufs[i]));
+	free_rbufs(info, i, i);
+	return 1;
+}
+
+static void reset_tbufs(struct slgt_info *info)
+{
+	unsigned int i;
+	info->tbuf_current = 0;
+	for (i=0 ; i < info->tbuf_count ; i++) {
+		info->tbufs[i].status = 0;
+		info->tbufs[i].count  = 0;
+	}
+}
+
+/*
+ * return number of free transmit DMA buffers
+ */
+static unsigned int free_tbuf_count(struct slgt_info *info)
+{
+	unsigned int count = 0;
+	unsigned int i = info->tbuf_current;
+
+	do
+	{
+		if (desc_count(info->tbufs[i]))
+			break; /* buffer in use */
+		++count;
+		if (++i == info->tbuf_count)
+			i=0;
+	} while (i != info->tbuf_current);
+
+	/* last buffer with zero count may be in use, assume it is */
+	if (count)
+		--count;
+
+	return count;
+}
+
+/*
+ * load transmit DMA buffer(s) with data
+ */
+static void tx_load(struct slgt_info *info, const char *buf, unsigned int size)
+{
+	unsigned short count;
+	unsigned int i;
+	struct slgt_desc *d;
+
+	if (size == 0)
+		return;
+
+	DBGDATA(info, buf, size, "tx");
+
+	info->tbuf_start = i = info->tbuf_current;
+
+	while (size) {
+		d = &info->tbufs[i];
+		if (++i == info->tbuf_count)
+			i = 0;
+
+		count = (unsigned short)((size > DMABUFSIZE) ? DMABUFSIZE : size);
+		memcpy(d->buf, buf, count);
+
+		size -= count;
+		buf  += count;
+
+		if (!size && info->params.mode != MGSL_MODE_RAW)
+			set_desc_eof(*d, 1); /* HDLC: set EOF of last desc */
+		else
+			set_desc_eof(*d, 0);
+
+		set_desc_count(*d, count);
+	}
+
+	info->tbuf_current = i;
+}
+
+static int register_test(struct slgt_info *info)
+{
+	static unsigned short patterns[] =
+		{0x0000, 0xffff, 0xaaaa, 0x5555, 0x6969, 0x9696};
+	static unsigned int count = sizeof(patterns)/sizeof(patterns[0]);
+	unsigned int i;
+	int rc = 0;
+
+	for (i=0 ; i < count ; i++) {
+		wr_reg16(info, TIR, patterns[i]);
+		wr_reg16(info, BDR, patterns[(i+1)%count]);
+		if ((rd_reg16(info, TIR) != patterns[i]) ||
+		    (rd_reg16(info, BDR) != patterns[(i+1)%count])) {
+			rc = -ENODEV;
+			break;
+		}
+	}
+
+	info->init_error = rc ? 0 : DiagStatus_AddressFailure;
+	return rc;
+}
+
+static int irq_test(struct slgt_info *info)
+{
+	unsigned long timeout;
+	unsigned long flags;
+	struct tty_struct *oldtty = info->tty;
+	u32 speed = info->params.data_rate;
+
+	info->params.data_rate = 921600;
+	info->tty = NULL;
+
+	spin_lock_irqsave(&info->lock, flags);
+	async_mode(info);
+	slgt_irq_on(info, IRQ_TXIDLE);
+
+	/* enable transmitter */
+	wr_reg16(info, TCR,
+		(unsigned short)(rd_reg16(info, TCR) | BIT1));
+
+	/* write one byte and wait for tx idle */
+	wr_reg16(info, TDR, 0);
+
+	/* assume failure */
+	info->init_error = DiagStatus_IrqFailure;
+	info->irq_occurred = FALSE;
+
+	spin_unlock_irqrestore(&info->lock, flags);
+
+	timeout=100;
+	while(timeout-- && !info->irq_occurred)
+		msleep_interruptible(10);
+
+	spin_lock_irqsave(&info->lock,flags);
+	reset_port(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	info->params.data_rate = speed;
+	info->tty = oldtty;
+
+	info->init_error = info->irq_occurred ? 0 : DiagStatus_IrqFailure;
+	return info->irq_occurred ? 0 : -ENODEV;
+}
+
+static int loopback_test_rx(struct slgt_info *info)
+{
+	unsigned char *src, *dest;
+	int count;
+
+	if (desc_complete(info->rbufs[0])) {
+		count = desc_count(info->rbufs[0]);
+		src   = info->rbufs[0].buf;
+		dest  = info->tmp_rbuf;
+
+		for( ; count ; count-=2, src+=2) {
+			/* src=data byte (src+1)=status byte */
+			if (!(*(src+1) & (BIT9 + BIT8))) {
+				*dest = *src;
+				dest++;
+				info->tmp_rbuf_count++;
+			}
+		}
+		DBGDATA(info, info->tmp_rbuf, info->tmp_rbuf_count, "rx");
+		return 1;
+	}
+	return 0;
+}
+
+static int loopback_test(struct slgt_info *info)
+{
+#define TESTFRAMESIZE 20
+
+	unsigned long timeout;
+	u16 count = TESTFRAMESIZE;
+	unsigned char buf[TESTFRAMESIZE];
+	int rc = -ENODEV;
+	unsigned long flags;
+
+	struct tty_struct *oldtty = info->tty;
+	MGSL_PARAMS params;
+
+	memcpy(&params, &info->params, sizeof(params));
+
+	info->params.mode = MGSL_MODE_ASYNC;
+	info->params.data_rate = 921600;
+	info->params.loopback = 1;
+	info->tty = NULL;
+
+	/* build and send transmit frame */
+	for (count = 0; count < TESTFRAMESIZE; ++count)
+		buf[count] = (unsigned char)count;
+
+	info->tmp_rbuf_count = 0;
+	memset(info->tmp_rbuf, 0, TESTFRAMESIZE);
+
+	/* program hardware for HDLC and enabled receiver */
+	spin_lock_irqsave(&info->lock,flags);
+	async_mode(info);
+	rx_start(info);
+	info->tx_count = count;
+	tx_load(info, buf, count);
+	tx_start(info);
+	spin_unlock_irqrestore(&info->lock, flags);
+
+	/* wait for receive complete */
+	for (timeout = 100; timeout; --timeout) {
+		msleep_interruptible(10);
+		if (loopback_test_rx(info)) {
+			rc = 0;
+			break;
+		}
+	}
+
+	/* verify received frame length and contents */
+	if (!rc && (info->tmp_rbuf_count != count ||
+		  memcmp(buf, info->tmp_rbuf, count))) {
+		rc = -ENODEV;
+	}
+
+	spin_lock_irqsave(&info->lock,flags);
+	reset_adapter(info);
+	spin_unlock_irqrestore(&info->lock,flags);
+
+	memcpy(&info->params, &params, sizeof(info->params));
+	info->tty = oldtty;
+
+	info->init_error = rc ? DiagStatus_DmaFailure : 0;
+	return rc;
+}
+
+static int adapter_test(struct slgt_info *info)
+{
+	DBGINFO(("testing %s\n", info->device_name));
+	if ((info->init_error = register_test(info)) < 0) {
+		printk("register test failure %s addr=%08X\n",
+			info->device_name, info->phys_reg_addr);
+	} else if ((info->init_error = irq_test(info)) < 0) {
+		printk("IRQ test failure %s IRQ=%d\n",
+			info->device_name, info->irq_level);
+	} else if ((info->init_error = loopback_test(info)) < 0) {
+		printk("loopback test failure %s\n", info->device_name);
+	}
+	return info->init_error;
+}
+
+/*
+ * transmit timeout handler
+ */
+static void tx_timeout(unsigned long context)
+{
+	struct slgt_info *info = (struct slgt_info*)context;
+	unsigned long flags;
+
+	DBGINFO(("%s tx_timeout\n", info->device_name));
+	if(info->tx_active && info->params.mode == MGSL_MODE_HDLC) {
+		info->icount.txtimeout++;
+	}
+	spin_lock_irqsave(&info->lock,flags);
+	info->tx_active = 0;
+	info->tx_count = 0;
+	spin_unlock_irqrestore(&info->lock,flags);
+
+#ifdef CONFIG_HDLC
+	if (info->netcount)
+		hdlcdev_tx_done(info);
+	else
+#endif
+		bh_transmit(info);
+}
+
+/*
+ * receive buffer polling timer
+ */
+static void rx_timeout(unsigned long context)
+{
+	struct slgt_info *info = (struct slgt_info*)context;
+	unsigned long flags;
+
+	DBGINFO(("%s rx_timeout\n", info->device_name));
+	spin_lock_irqsave(&info->lock, flags);
+	info->pending_bh |= BH_RECEIVE;
+	spin_unlock_irqrestore(&info->lock, flags);
+	bh_handler(info);
+}
+