[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>

1 files changed, 4501 insertions, 0 deletions

diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
new file mode 100644
index 00000000000..2b9cde94e2f
--- /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_eve