[IPV6]: Add ip6_tunnel.h to headers_install

The Mobile IPv6 package (http://www.mobile-ipv6.org/software/) needs
this header file to build the tunnelctl component. The header
already looks sanitized so is safe to export.

Signed-off-by: Deepak Saxena <dsaxena@mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/Kbuild b/include/linux/Kbuild
index bcd01f269f6..e1013156c25 100644
--- a/include/linux/Kbuild
+++ b/include/linux/Kbuild
@@ -239,6 +239,7 @@ unifdef-y += ipc.h
 unifdef-y += ipmi.h
 unifdef-y += ipv6.h
 unifdef-y += ipv6_route.h
+unifdef-y += ip6_tunnel.h
 unifdef-y += isdn.h
 unifdef-y += isdnif.h
 unifdef-y += isdn_divertif.h

/*
 * $Id: synclink_gt.c,v 4.50 2007/07/25 19:29:25 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/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/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"

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

/*
 * module identification
 */
static char *driver_name     = "SyncLink GT";
static char *driver_version  = "$Revision: 4.50 $";
static char *tty_driver_name = "synclink_gt";
static char *tty_dev_prefix  = "ttySLG";
MODULE_LICENSE("GPL");
#define MGSL_MAGIC 0x5401
#define MAX_DEVICES 32

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_GT2_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
 */
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 ktermios *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
 */
#if SYNCLINK_GENERIC_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

/*
 * conditional wait facility
 */
struct cond_wait {
	struct cond_wait *next;
	wait_queue_head_t q;
	wait_queue_t wait;
	unsigned int data;
};
static void init_cond_wait(struct cond_wait *w, unsigned int data);
static void add_cond_wait(struct cond_wait **head, struct cond_wait *w);
static void remove_cond_wait(struct cond_wait **head, struct cond_wait *w);
static void flush_cond_wait(struct cond_wait **head);

/*
 * DMA buffer descriptor and access macros
 */
struct slgt_desc
{
	__le16 count;
	__le16 status;
	__le32 pbuf;  /* physical address of data buffer */
	__le32 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;

	unsigned int            gpio_present;
	struct cond_wait        *gpio_wait_q;

	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;
	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 */
	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;
#if SYNCLINK_GENERIC_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 BIT0
#define MASK_BREAK   BIT14
#define MASK_OVERRUN BIT4

#define GSR   0x00 /* global status */
#define JCR   0x04 /* JTAG control */
#define IODR  0x08 /* GPIO direction */
#define IOER  0x0c /* GPIO interrupt enable */
#define IOVR  0x10 /* GPIO value */
#define IOSR  0x14 /* GPIO interrupt 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 sync_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 tdma_start(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(struct work_struct *work);
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);

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);
static int  set_gpio(struct slgt_info *info, struct gpio_desc __user *gpio);
static int  get_gpio(struct slgt_info *info, struct gpio_desc __user *gpio);
static int  wait_gpio(struct slgt_info *info, struct gpio_desc __user *gpio);

/*
 * 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 ktermios *old_termios)
{
	struct slgt_info *info = tty->driver_data;
	unsigned long flags;

	DBGINFO(("%s set_termios\n", tty->driver->name));

	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 (!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 ||
	    info->params.mode == MGSL_MODE_MONOSYNC ||
	    info->params.mode == MGSL_MODE_BISYNC) {
		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);
		else
			tdma_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 (!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);

	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) &&