/*****************************************************************************/

/*
 *      stallion.c  -- stallion multiport serial driver.
 *
 *      Copyright (C) 1996-1999  Stallion Technologies
 *      Copyright (C) 1994-1996  Greg Ungerer.
 *
 *      This code is loosely based on the Linux serial driver, written by
 *      Linus Torvalds, Theodore T'so and others.
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation; either version 2 of the License, or
 *      (at your option) any later version.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU General Public License for more details.
 *
 *      You should have received a copy of the GNU General Public License
 *      along with this program; if not, write to the Free Software
 *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*****************************************************************************/

#include <linux/config.h>
#include <linux/module.h>
#include <linux/version.h> /* for linux/stallion.h */
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/cd1400.h>
#include <linux/sc26198.h>
#include <linux/comstats.h>
#include <linux/stallion.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>

#include <asm/io.h>
#include <asm/uaccess.h>

#ifdef CONFIG_PCI
#include <linux/pci.h>
#endif

/*****************************************************************************/

/*
 *      Define different board types. Use the standard Stallion "assigned"
 *      board numbers. Boards supported in this driver are abbreviated as
 *      EIO = EasyIO and ECH = EasyConnection 8/32.
 */
#define BRD_EASYIO      20
#define BRD_ECH         21
#define BRD_ECHMC       22
#define BRD_ECHPCI      26
#define BRD_ECH64PCI    27
#define BRD_EASYIOPCI   28

/*
 *      Define a configuration structure to hold the board configuration.
 *      Need to set this up in the code (for now) with the boards that are
 *      to be configured into the system. This is what needs to be modified
 *      when adding/removing/modifying boards. Each line entry in the
 *      stl_brdconf[] array is a board. Each line contains io/irq/memory
 *      ranges for that board (as well as what type of board it is).
 *      Some examples:
 *              { BRD_EASYIO, 0x2a0, 0, 0, 10, 0 },
 *      This line would configure an EasyIO board (4 or 8, no difference),
 *      at io address 2a0 and irq 10.
 *      Another example:
 *              { BRD_ECH, 0x2a8, 0x280, 0, 12, 0 },
 *      This line will configure an EasyConnection 8/32 board at primary io
 *      address 2a8, secondary io address 280 and irq 12.
 *      Enter as many lines into this array as you want (only the first 4
 *      will actually be used!). Any combination of EasyIO and EasyConnection
 *      boards can be specified. EasyConnection 8/32 boards can share their
 *      secondary io addresses between each other.
 *
 *      NOTE: there is no need to put any entries in this table for PCI
 *      boards. They will be found automatically by the driver - provided
 *      PCI BIOS32 support is compiled into the kernel.
 */

typedef struct {
        int             brdtype;
        int             ioaddr1;
        int             ioaddr2;
        unsigned long   memaddr;
        int             irq;
        int             irqtype;
} stlconf_t;

static stlconf_t        stl_brdconf[] = {
        /*{ BRD_EASYIO, 0x2a0, 0, 0, 10, 0 },*/
};

static int      stl_nrbrds = sizeof(stl_brdconf) / sizeof(stlconf_t);

/*****************************************************************************/

/*
 *      Define some important driver characteristics. Device major numbers
 *      allocated as per Linux Device Registry.
 */
#ifndef STL_SIOMEMMAJOR
#define STL_SIOMEMMAJOR         28
#endif
#ifndef STL_SERIALMAJOR
#define STL_SERIALMAJOR         24
#endif
#ifndef STL_CALLOUTMAJOR
#define STL_CALLOUTMAJOR        25
#endif

#define STL_DRVTYPSERIAL        1
#define STL_DRVTYPCALLOUT       2

/*
 *      Set the TX buffer size. Bigger is better, but we don't want
 *      to chew too much memory with buffers!
 */
#define STL_TXBUFLOW            512
#define STL_TXBUFSIZE           4096

/*****************************************************************************/

/*
 *      Define our local driver identity first. Set up stuff to deal with
 *      all the local structures required by a serial tty driver.
 */
static char     *stl_drvtitle = "Stallion Multiport Serial Driver";
static char     *stl_drvname = "stallion";
static char     *stl_drvversion = "5.6.0";
#ifdef CONFIG_DEVFS_FS
static char     *stl_serialname = "tts/E%d";
static char     *stl_calloutname = "cua/E%d";
#else
static char     *stl_serialname = "ttyE";
static char     *stl_calloutname = "cue";
#endif

static struct tty_driver        stl_serial;
static struct tty_driver        stl_callout;
static struct tty_struct        *stl_ttys[STL_MAXDEVS];
static struct termios           *stl_termios[STL_MAXDEVS];
static struct termios           *stl_termioslocked[STL_MAXDEVS];
static int                      stl_refcount;

/*
 *      We will need to allocate a temporary write buffer for chars that
 *      come direct from user space. The problem is that a copy from user
 *      space might cause a page fault (typically on a system that is
 *      swapping!). All ports will share one buffer - since if the system
 *      is already swapping a shared buffer won't make things any worse.
 */
static char                     *stl_tmpwritebuf;
static DECLARE_MUTEX(stl_tmpwritesem);

/*
 *      Define a local default termios struct. All ports will be created
 *      with this termios initially. Basically all it defines is a raw port
 *      at 9600, 8 data bits, 1 stop bit.
 */
static struct termios           stl_deftermios = {
        c_cflag:        (B9600 | CS8 | CREAD | HUPCL | CLOCAL),
        c_cc:           INIT_C_CC,
};

/*
 *      Define global stats structures. Not used often, and can be
 *      re-used for each stats call.
 */
static comstats_t       stl_comstats;
static combrd_t         stl_brdstats;
static stlbrd_t         stl_dummybrd;
static stlport_t        stl_dummyport;

/*
 *      Define global place to put buffer overflow characters.
 */
static char             stl_unwanted[SC26198_RXFIFOSIZE];

/*****************************************************************************/

static stlbrd_t         *stl_brds[STL_MAXBRDS];

/*
 *      Per board state flags. Used with the state field of the board struct.
 *      Not really much here!
 */
#define BRD_FOUND       0x1

/*
 *      Define the port structure istate flags. These set of flags are
 *      modified at interrupt time - so setting and reseting them needs
 *      to be atomic. Use the bit clear/setting routines for this.
 */
#define ASYI_TXBUSY     1
#define ASYI_TXLOW      2
#define ASYI_DCDCHANGE  3
#define ASYI_TXFLOWED   4

/*
 *      Define an array of board names as printable strings. Handy for
 *      referencing boards when printing trace and stuff.
 */
static char     *stl_brdnames[] = {
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        "EasyIO",
        "EC8/32-AT",
        "EC8/32-MC",
        (char *) NULL,
        (char *) NULL,
        (char *) NULL,
        "EC8/32-PCI",
        "EC8/64-PCI",
        "EasyIO-PCI",
};

/*****************************************************************************/

#ifdef MODULE
/*
 *      Define some string labels for arguments passed from the module
 *      load line. These allow for easy board definitions, and easy
 *      modification of the io, memory and irq resoucres.
 */

static char     *board0[4];
static char     *board1[4];
static char     *board2[4];
static char     *board3[4];

static char     **stl_brdsp[] = {
        (char **) &board0,
        (char **) &board1,
        (char **) &board2,
        (char **) &board3
};

/*
 *      Define a set of common board names, and types. This is used to
 *      parse any module arguments.
 */

typedef struct stlbrdtype {
        char    *name;
        int     type;
} stlbrdtype_t;

static stlbrdtype_t     stl_brdstr[] = {
        { "easyio", BRD_EASYIO },
        { "eio", BRD_EASYIO },
        { "20", BRD_EASYIO },
        { "ec8/32", BRD_ECH },
        { "ec8/32-at", BRD_ECH },
        { "ec8/32-isa", BRD_ECH },
        { "ech", BRD_ECH },
        { "echat", BRD_ECH },
        { "21", BRD_ECH },
        { "ec8/32-mc", BRD_ECHMC },
        { "ec8/32-mca", BRD_ECHMC },
        { "echmc", BRD_ECHMC },
        { "echmca", BRD_ECHMC },
        { "22", BRD_ECHMC },
        { "ec8/32-pc", BRD_ECHPCI },
        { "ec8/32-pci", BRD_ECHPCI },
        { "26", BRD_ECHPCI },
        { "ec8/64-pc", BRD_ECH64PCI },
        { "ec8/64-pci", BRD_ECH64PCI },
        { "ech-pci", BRD_ECH64PCI },
        { "echpci", BRD_ECH64PCI },
        { "echpc", BRD_ECH64PCI },
        { "27", BRD_ECH64PCI },
        { "easyio-pc", BRD_EASYIOPCI },
        { "easyio-pci", BRD_EASYIOPCI },
        { "eio-pci", BRD_EASYIOPCI },
        { "eiopci", BRD_EASYIOPCI },
        { "28", BRD_EASYIOPCI },
};

/*
 *      Define the module agruments.
 */
MODULE_AUTHOR("Greg Ungerer");
MODULE_DESCRIPTION("Stallion Multiport Serial Driver");
MODULE_LICENSE("GPL");

MODULE_PARM(board0, "1-4s");
MODULE_PARM_DESC(board0, "Board 0 config -> name[,ioaddr[,ioaddr2][,irq]]");
MODULE_PARM(board1, "1-4s");
MODULE_PARM_DESC(board1, "Board 1 config -> name[,ioaddr[,ioaddr2][,irq]]");
MODULE_PARM(board2, "1-4s");
MODULE_PARM_DESC(board2, "Board 2 config -> name[,ioaddr[,ioaddr2][,irq]]");
MODULE_PARM(board3, "1-4s");
MODULE_PARM_DESC(board3, "Board 3 config -> name[,ioaddr[,ioaddr2][,irq]]");

#endif

/*****************************************************************************/

/*
 *      Hardware ID bits for the EasyIO and ECH boards. These defines apply
 *      to the directly accessible io ports of these boards (not the uarts -
 *      they are in cd1400.h and sc26198.h).
 */
#define EIO_8PORTRS     0x04
#define EIO_4PORTRS     0x05
#define EIO_8PORTDI     0x00
#define EIO_8PORTM      0x06
#define EIO_MK3         0x03
#define EIO_IDBITMASK   0x07

#define EIO_BRDMASK     0xf0
#define ID_BRD4         0x10
#define ID_BRD8         0x20
#define ID_BRD16        0x30

#define EIO_INTRPEND    0x08
#define EIO_INTEDGE     0x00
#define EIO_INTLEVEL    0x08
#define EIO_0WS         0x10

#define ECH_ID          0xa0
#define ECH_IDBITMASK   0xe0
#define ECH_BRDENABLE   0x08
#define ECH_BRDDISABLE  0x00
#define ECH_INTENABLE   0x01
#define ECH_INTDISABLE  0x00
#define ECH_INTLEVEL    0x02
#define ECH_INTEDGE     0x00
#define ECH_INTRPEND    0x01
#define ECH_BRDRESET    0x01

#define ECHMC_INTENABLE 0x01
#define ECHMC_BRDRESET  0x02

#define ECH_PNLSTATUS   2
#define ECH_PNL16PORT   0x20
#define ECH_PNLIDMASK   0x07
#define ECH_PNLXPID     0x40
#define ECH_PNLINTRPEND 0x80

#define ECH_ADDR2MASK   0x1e0

/*
 *      Define the vector mapping bits for the programmable interrupt board
 *      hardware. These bits encode the interrupt for the board to use - it
 *      is software selectable (except the EIO-8M).
 */
static unsigned char    stl_vecmap[] = {
        0xff, 0xff, 0xff, 0x04, 0x06, 0x05, 0xff, 0x07,
        0xff, 0xff, 0x00, 0x02, 0x01, 0xff, 0xff, 0x03
};

/*
 *      Set up enable and disable macros for the ECH boards. They require
 *      the secondary io address space to be activated and deactivated.
 *      This way all ECH boards can share their secondary io region.
 *      If this is an ECH-PCI board then also need to set the page pointer
 *      to point to the correct page.
 */
#define BRDENABLE(brdnr,pagenr)                                         \
        if (stl_brds[(brdnr)]->brdtype == BRD_ECH)                      \
                outb((stl_brds[(brdnr)]->ioctrlval | ECH_BRDENABLE),    \
                        stl_brds[(brdnr)]->ioctrl);                     \
        else if (stl_brds[(brdnr)]->brdtype == BRD_ECHPCI)              \
                outb((pagenr), stl_brds[(brdnr)]->ioctrl);

#define BRDDISABLE(brdnr)                                               \
        if (stl_brds[(brdnr)]->brdtype == BRD_ECH)                      \
                outb((stl_brds[(brdnr)]->ioctrlval | ECH_BRDDISABLE),   \
                        stl_brds[(brdnr)]->ioctrl);

#define STL_CD1400MAXBAUD       230400
#define STL_SC26198MAXBAUD      460800

#define STL_BAUDBASE            115200
#define STL_CLOSEDELAY          (5 * HZ / 10)

/*****************************************************************************/

#ifdef CONFIG_PCI

/*
 *      Define the Stallion PCI vendor and device IDs.
 */
#ifndef PCI_VENDOR_ID_STALLION
#define PCI_VENDOR_ID_STALLION          0x124d
#endif
#ifndef PCI_DEVICE_ID_ECHPCI832
#define PCI_DEVICE_ID_ECHPCI832         0x0000
#endif
#ifndef PCI_DEVICE_ID_ECHPCI864
#define PCI_DEVICE_ID_ECHPCI864         0x0002
#endif
#ifndef PCI_DEVICE_ID_EIOPCI
#define PCI_DEVICE_ID_EIOPCI            0x0003
#endif

/*
 *      Define structure to hold all Stallion PCI boards.
 */
typedef struct stlpcibrd {
        unsigned short          vendid;
        unsigned short          devid;
        int                     brdtype;
} stlpcibrd_t;

static stlpcibrd_t      stl_pcibrds[] = {
        { PCI_VENDOR_ID_STALLION, PCI_DEVICE_ID_ECHPCI864, BRD_ECH64PCI },
        { PCI_VENDOR_ID_STALLION, PCI_DEVICE_ID_EIOPCI, BRD_EASYIOPCI },
        { PCI_VENDOR_ID_STALLION, PCI_DEVICE_ID_ECHPCI832, BRD_ECHPCI },
        { PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_87410, BRD_ECHPCI },
};

static int      stl_nrpcibrds = sizeof(stl_pcibrds) / sizeof(stlpcibrd_t);

#endif

/*****************************************************************************/

/*
 *      Define macros to extract a brd/port number from a minor number.
 */
#define MINOR2BRD(min)          (((min) & 0xc0) >> 6)
#define MINOR2PORT(min)         ((min) & 0x3f)

/*
 *      Define a baud rate table that converts termios baud rate selector
 *      into the actual baud rate value. All baud rate calculations are
 *      based on the actual baud rate required.
 */
static unsigned int     stl_baudrates[] = {
        0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
        9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600
};

/*
 *      Define some handy local macros...
 */
#undef  MIN
#define MIN(a,b)        (((a) <= (b)) ? (a) : (b))

#undef  TOLOWER
#define TOLOWER(x)      ((((x) >= 'A') && ((x) <= 'Z')) ? ((x) + 0x20) : (x))

/*****************************************************************************/

/*
 *      Declare all those functions in this driver!
 */

#ifdef MODULE
int             init_module(void);
void            cleanup_module(void);
static void     stl_argbrds(void);
static int      stl_parsebrd(stlconf_t *confp, char **argp);

static unsigned long stl_atol(char *str);
#endif

int             stl_init(void);
static int      stl_open(struct tty_struct *tty, struct file *filp);
static void     stl_close(struct tty_struct *tty, struct file *filp);
static int      stl_write(struct tty_struct *tty, int from_user, const unsigned char *buf, int count);
static void     stl_putchar(struct tty_struct *tty, unsigned char ch);
static void     stl_flushchars(struct tty_struct *tty);
static int      stl_writeroom(struct tty_struct *tty);
static int      stl_charsinbuffer(struct tty_struct *tty);
static int      stl_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg);
static void     stl_settermios(struct tty_struct *tty, struct termios *old);
static void     stl_throttle(struct tty_struct *tty);
static void     stl_unthrottle(struct tty_struct *tty);
static void     stl_stop(struct tty_struct *tty);
static void     stl_start(struct tty_struct *tty);
static void     stl_flushbuffer(struct tty_struct *tty);
static void     stl_breakctl(struct tty_struct *tty, int state);
static void     stl_waituntilsent(struct tty_struct *tty, int timeout);
static void     stl_sendxchar(struct tty_struct *tty, char ch);
static void     stl_hangup(struct tty_struct *tty);
static int      stl_memioctl(struct inode *ip, struct file *fp, unsigned int cmd, unsigned long arg);
static int      stl_portinfo(stlport_t *portp, int portnr, char *pos);
static int      stl_readproc(char *page, char **start, off_t off, int count, int *eof, void *data);

static int      stl_brdinit(stlbrd_t *brdp);
static int      stl_initports(stlbrd_t *brdp, stlpanel_t *panelp);
static void     stl_getserial(stlport_t *portp, struct serial_struct *sp);
static int      stl_setserial(stlport_t *portp, struct serial_struct *sp);
static int      stl_getbrdstats(combrd_t *bp);
static int      stl_getportstats(stlport_t *portp, comstats_t *cp);
static int      stl_clrportstats(stlport_t *portp, comstats_t *cp);
static int      stl_getportstruct(unsigned long arg);
static int      stl_getbrdstruct(unsigned long arg);
static int      stl_waitcarrier(stlport_t *portp, struct file *filp);
static void     stl_delay(int len);
static void     stl_intr(int irq, void *dev_id, struct pt_regs *regs);
static void     stl_eiointr(stlbrd_t *brdp);
static void     stl_echatintr(stlbrd_t *brdp);
static void     stl_echmcaintr(stlbrd_t *brdp);
static void     stl_echpciintr(stlbrd_t *brdp);
static void     stl_echpci64intr(stlbrd_t *brdp);
static void     stl_offintr(void *private);
static void     *stl_memalloc(int len);
static stlbrd_t *stl_allocbrd(void);
static stlport_t *stl_getport(int brdnr, int panelnr, int portnr);

static inline int       stl_initbrds(void);
static inline int       stl_initeio(stlbrd_t *brdp);
static inline int       stl_initech(stlbrd_t *brdp);
static inline int       stl_getbrdnr(void);

#ifdef  CONFIG_PCI
static inline int       stl_findpcibrds(void);
static inline int       stl_initpcibrd(int brdtype, struct pci_dev *devp);
#endif

/*
 *      CD1400 uart specific handling functions.
 */
static void     stl_cd1400setreg(stlport_t *portp, int regnr, int value);
static int      stl_cd1400getreg(stlport_t *portp, int regnr);
static int      stl_cd1400updatereg(stlport_t *portp, int regnr, int value);
static int      stl_cd1400panelinit(stlbrd_t *brdp, stlpanel_t *panelp);
static void     stl_cd1400portinit(stlbrd_t *brdp, stlpanel_t *panelp, stlport_t *portp);
static void     stl_cd1400setport(stlport_t *portp, struct termios *tiosp);
static int      stl_cd1400getsignals(stlport_t *portp);
static void     stl_cd1400setsignals(stlport_t *portp, int dtr, int rts);
static void     stl_cd1400ccrwait(stlport_t *portp);
static void     stl_cd1400enablerxtx(stlport_t *portp, int rx, int tx);
static void     stl_cd1400startrxtx(stlport_t *portp, int rx, int tx);
static void     stl_cd1400disableintrs(stlport_t *portp);
static void     stl_cd1400sendbreak(stlport_t *portp, int len);
static void     stl_cd1400flowctrl(stlport_t *portp, int state);
static void     stl_cd1400sendflow(stlport_t *portp, int state);
static void     stl_cd1400flush(stlport_t *portp);
static int      stl_cd1400datastate(stlport_t *portp);
static void     stl_cd1400eiointr(stlpanel_t *panelp, unsigned int iobase);
static void     stl_cd1400echintr(stlpanel_t *panelp, unsigned int iobase);
static void     stl_cd1400txisr(stlpanel_t *panelp, int ioaddr);
static void     stl_cd1400rxisr(stlpanel_t *panelp, int ioaddr);
static void     stl_cd1400mdmisr(stlpanel_t *panelp, int ioaddr);

static inline int       stl_cd1400breakisr(stlport_t *portp, int ioaddr);

/*
 *      SC26198 uart specific handling functions.
 */
static void     stl_sc26198setreg(stlport_t *portp, int regnr, int value);
static int      stl_sc26198getreg(stlport_t *portp, int regnr);
static int      stl_sc26198updatereg(stlport_t *portp, int regnr, int value);
static int      stl_sc26198getglobreg(stlport_t *portp, int regnr);
static int      stl_sc26198panelinit(stlbrd_t *brdp, stlpanel_t *panelp);
static void     stl_sc26198portinit(stlbrd_t *brdp, stlpanel_t *panelp, stlport_t *portp);
static void     stl_sc26198setport(stlport_t *portp, struct termios *tiosp);
static int      stl_sc26198getsignals(stlport_t *portp);
static void     stl_sc26198setsignals(stlport_t *portp, int dtr, int rts);
static void     stl_sc26198enablerxtx(stlport_t *portp, int rx, int tx);
static void     stl_sc26198startrxtx(stlport_t *portp, int rx, int tx);
static void     stl_sc26198disableintrs(stlport_t *portp);
static void     stl_sc26198sendbreak(stlport_t *portp, int len);
static void     stl_sc26198flowctrl(stlport_t *portp, int state);
static void     stl_sc26198sendflow(stlport_t *portp, int state);
static void     stl_sc26198flush(stlport_t *portp);
static int      stl_sc26198datastate(stlport_t *portp);
static void     stl_sc26198wait(stlport_t *portp);
static void     stl_sc26198txunflow(stlport_t *portp, struct tty_struct *tty);
static void     stl_sc26198intr(stlpanel_t *panelp, unsigned int iobase);
static void     stl_sc26198txisr(stlport_t *port);
static void     stl_sc26198rxisr(stlport_t *port, unsigned int iack);
static void     stl_sc26198rxbadch(stlport_t *portp, unsigned char status, char ch);
static void     stl_sc26198rxbadchars(stlport_t *portp);
static void     stl_sc26198otherisr(stlport_t *port, unsigned int iack);

/*****************************************************************************/

/*
 *      Generic UART support structure.
 */
typedef struct uart {
        int     (*panelinit)(stlbrd_t *brdp, stlpanel_t *panelp);
        void    (*portinit)(stlbrd_t *brdp, stlpanel_t *panelp, stlport_t *portp);
        void    (*setport)(stlport_t *portp, struct termios *tiosp);
        int     (*getsignals)(stlport_t *portp);
        void    (*setsignals)(stlport_t *portp, int dtr, int rts);
        void    (*enablerxtx)(stlport_t *portp, int rx, int tx);
        void    (*startrxtx)(stlport_t *portp, int rx, int tx);
        void    (*disableintrs)(stlport_t *portp);
        void    (*sendbreak)(stlport_t *portp, int len);
        void    (*flowctrl)(stlport_t *portp, int state);
        void    (*sendflow)(stlport_t *portp, int state);
        void    (*flush)(stlport_t *portp);
        int     (*datastate)(stlport_t *portp);
        void    (*intr)(stlpanel_t *panelp, unsigned int iobase);
} uart_t;

/*
 *      Define some macros to make calling these functions nice and clean.
 */
#define stl_panelinit           (* ((uart_t *) panelp->uartp)->panelinit)
#define stl_portinit            (* ((uart_t *) portp->uartp)->portinit)
#define stl_setport             (* ((uart_t *) portp->uartp)->setport)
#define stl_getsignals          (* ((uart_t *) portp->uartp)->getsignals)
#define stl_setsignals          (* ((uart_t *) portp->uartp)->setsignals)
#define stl_enablerxtx          (* ((uart_t *) portp->uartp)->enablerxtx)
#define stl_startrxtx           (* ((uart_t *) portp->uartp)->startrxtx)
#define stl_disableintrs        (* ((uart_t *) portp->uartp)->disableintrs)
#define stl_sendbreak           (* ((uart_t *) portp->uartp)->sendbreak)
#define stl_flowctrl            (* ((uart_t *) portp->uartp)->flowctrl)
#define stl_sendflow            (* ((uart_t *) portp->uartp)->sendflow)
#define stl_flush               (* ((uart_t *) portp->uartp)->flush)
#define stl_datastate           (* ((uart_t *) portp->uartp)->datastate)

/*****************************************************************************/

/*
 *      CD1400 UART specific data initialization.
 */
static uart_t stl_cd1400uart = {
        stl_cd1400panelinit,
        stl_cd1400portinit,
        stl_cd1400setport,
        stl_cd1400getsignals,
        stl_cd1400setsignals,
        stl_cd1400enablerxtx,
        stl_cd1400startrxtx,
        stl_cd1400disableintrs,
        stl_cd1400sendbreak,
        stl_cd1400flowctrl,
        stl_cd1400sendflow,
        stl_cd1400flush,
        stl_cd1400datastate,
        stl_cd1400eiointr
};

/*
 *      Define the offsets within the register bank of a cd1400 based panel.
 *      These io address offsets are common to the EasyIO board as well.
 */
#define EREG_ADDR       0
#define EREG_DATA       4
#define EREG_RXACK      5
#define EREG_TXACK      6
#define EREG_MDACK      7

#define EREG_BANKSIZE   8

#define CD1400_CLK      25000000
#define CD1400_CLK8M    20000000

/*
 *      Define the cd1400 baud rate clocks. These are used when calculating
 *      what clock and divisor to use for the required baud rate. Also
 *      define the maximum baud rate allowed, and the default base baud.
 */
static int      stl_cd1400clkdivs[] = {
        CD1400_CLK0, CD1400_CLK1, CD1400_CLK2, CD1400_CLK3, CD1400_CLK4
};

/*****************************************************************************/

/*
 *      SC26198 UART specific data initization.
 */
static uart_t stl_sc26198uart = {
        stl_sc26198panelinit,
        stl_sc26198portinit,
        stl_sc26198setport,
        stl_sc26198getsignals,
        stl_sc26198setsignals,
        stl_sc26198enablerxtx,
        stl_sc26198startrxtx,
        stl_sc26198disableintrs,
        stl_sc26198sendbreak,
        stl_sc26198flowctrl,
        stl_sc26198sendflow,
        stl_sc26198flush,
        stl_sc26198datastate,
        stl_sc26198intr
};

/*
 *      Define the offsets within the register bank of a sc26198 based panel.
 */
#define XP_DATA         0
#define XP_ADDR         1
#define XP_MODID        2
#define XP_STATUS       2
#define XP_IACK         3

#define XP_BANKSIZE     4

/*
 *      Define the sc26198 baud rate table. Offsets within the table
 *      represent the actual baud rate selector of sc26198 registers.
 */
static unsigned int     sc26198_baudtable[] = {
        50, 75, 150, 200, 300, 450, 600, 900, 1200, 1800, 2400, 3600,
        4800, 7200, 9600, 14400, 19200, 28800, 38400, 57600, 115200,
        230400, 460800, 921600
};

#define SC26198_NRBAUDS         (sizeof(sc26198_baudtable) / sizeof(unsigned int))

/*****************************************************************************/

/*
 *      Define the driver info for a user level control device. Used mainly
 *      to get at port stats - only not using the port device itself.
 */
static struct file_operations   stl_fsiomem = {
        owner:          THIS_MODULE,
        ioctl:          stl_memioctl,
};

/*****************************************************************************/

static devfs_handle_t devfs_handle;

#ifdef MODULE

/*
 *      Loadable module initialization stuff.
 */

int init_module()
{
        unsigned long   flags;

#if DEBUG
        printk("init_module()\n");
#endif

        save_flags(flags);
        cli();
        stl_init();
        restore_flags(flags);

        return(0);
}

/*****************************************************************************/

void cleanup_module()
{
        stlbrd_t        *brdp;
        stlpanel_t      *panelp;
        stlport_t       *portp;
        unsigned long   flags;
        int             i, j, k;

#if DEBUG
        printk("cleanup_module()\n");
#endif

        printk(KERN_INFO "Unloading %s: version %s\n", stl_drvtitle,
                stl_drvversion);

        save_flags(flags);
        cli();

/*
 *      Free up all allocated resources used by the ports. This includes
 *      memory and interrupts. As part of this process we will also do
 *      a hangup on every open port - to try to flush out any processes
 *      hanging onto ports.
 */
        i = tty_unregister_driver(&stl_serial);
        j = tty_unregister_driver(&stl_callout);
        if (i || j) {
                printk("STALLION: failed to un-register tty driver, "
                        "errno=%d,%d\n", -i, -j);
                restore_flags(flags);
                return;
        }
        devfs_unregister (devfs_handle);
        if ((i = devfs_unregister_chrdev(STL_SIOMEMMAJOR, "staliomem")))
                printk("STALLION: failed to un-register serial memory device, "
                        "errno=%d\n", -i);

        if (stl_tmpwritebuf != (char *) NULL)
                kfree(stl_tmpwritebuf);

        for (i = 0; (i < stl_nrbrds); i++) {
                if ((brdp = stl_brds[i]) == (stlbrd_t *) NULL)
                        continue;
                for (j = 0; (j < STL_MAXPANELS); j++) {
                        panelp = brdp->panels[j];
                        if (panelp == (stlpanel_t *) NULL)
                                continue;
                        for (k = 0; (k < STL_PORTSPERPANEL); k++) {
                                portp = panelp->ports[k];
                                if (portp == (stlport_t *) NULL)
                                        continue;
                                if (portp->tty != (struct tty_struct *) NULL)
                                        stl_hangup(portp->tty);
                                if (portp->tx.buf != (char *) NULL)
                                        kfree(portp->tx.buf);
                                kfree(portp);
                        }
                        kfree(panelp);
                }
                free_irq(brdp->irq, brdp);

                release_region(brdp->ioaddr1, brdp->iosize1);
                if (brdp->iosize2 > 0)
                        release_region(brdp->ioaddr2, brdp->iosize2);

                kfree(brdp);
                stl_brds[i] = (stlbrd_t *) NULL;
        }
        restore_flags(flags);
}

/*****************************************************************************/

/*
 *      Check for any arguments passed in on the module load command line.
 */

static void stl_argbrds()
{
        stlconf_t       conf;
        stlbrd_t        *brdp;
        int             nrargs, i;

#if DEBUG
        printk("stl_argbrds()\n");
#endif

        nrargs = sizeof(stl_brdsp) / sizeof(char **);

        for (i = stl_nrbrds; (i < nrargs); i++) {
                memset(&conf, 0, sizeof(conf));
                if (stl_parsebrd(&conf, stl_brdsp[i]) == 0)
                        continue;
                if ((brdp = stl_allocbrd()) == (stlbrd_t *) NULL)
                        continue;
                stl_nrbrds = i + 1;
                brdp->brdnr = i;
                brdp->brdtype = conf.brdtype;
                brdp->ioaddr1 = conf.ioaddr1;
                brdp->ioaddr2 = conf.ioaddr2;
                brdp->irq = conf.irq;
                brdp->irqtype = conf.irqtype;
                stl_brdinit(brdp);
        }
}

/*****************************************************************************/

/*
 *      Convert an ascii string number into an unsigned long.
 */

static unsigned long stl_atol(char *str)
{
        unsigned long   val;
        int             base, c;
        char            *sp;

        val = 0;
        sp = str;
        if ((*sp == '0') && (*(sp+1) == 'x')) {
                base = 16;
                sp += 2;
        } else if (*sp == '0') {
                base = 8;
                sp++;
        } else {
                base = 10;
        }

        for (; (*sp != 0); sp++) {
                c = (*sp > '9') ? (TOLOWER(*sp) - 'a' + 10) : (*sp - '0');
                if ((c < 0) || (c >= base)) {
                        printk("STALLION: invalid argument %s\n", str);
                        val = 0;
                        break;
                }
                val = (val * base) + c;
        }
        return(val);
}

/*****************************************************************************/

/*
 *      Parse the supplied argument string, into the board conf struct.
 */

static int stl_parsebrd(stlconf_t *confp, char **argp)
{
        char    *sp;
        int     nrbrdnames, i;

#if DEBUG
        printk("stl_parsebrd(confp=%x,argp=%x)\n", (int) confp, (int) argp);
#endif

        if ((argp[0] == (char *) NULL) || (*argp[0] == 0))
                return(0);

        for (sp = argp[0], i = 0; ((*sp != 0) && (i < 25)); sp++, i++)
                *sp = TOLOWER(*sp);

        nrbrdnames = sizeof(stl_brdstr) / sizeof(stlbrdtype_t);
        for (i = 0; (i < nrbrdnames); i++) {
                if (strcmp(stl_brdstr[i].name, argp[0]) == 0)
                        break;
        }
        if (i >= nrbrdnames) {
                printk("STALLION: unknown board name, %s?\n", argp[0]);
                return(0);
        }

        confp->brdtype = stl_brdstr[i].type;

        i = 1;
        if ((argp[i] != (char *) NULL) && (*argp[i] != 0))
                confp->ioaddr1 = stl_atol(argp[i]);
        i++;
        if (confp->brdtype == BRD_ECH) {
                if ((argp[i] != (char *) NULL) && (*argp[i] != 0))
                        confp->ioaddr2 = stl_atol(argp[i]);
                i++;
        }
        if ((argp[i] != (char *) NULL) && (*argp[i] != 0))
                confp->irq = stl_atol(argp[i]);
        return(1);
}

#endif

/*****************************************************************************/

/*
 *      Local driver kernel memory allocation routine.
 */

static void *stl_memalloc(int len)
{
        return((void *) kmalloc(len, GFP_KERNEL));
}

/*****************************************************************************/

/*
 *      Allocate a new board structure. Fill out the basic info in it.
 */

static stlbrd_t *stl_allocbrd()
{
        stlbrd_t        *brdp;

        brdp = (stlbrd_t *) stl_memalloc(sizeof(stlbrd_t));
        if (brdp == (stlbrd_t *) NULL) {
                printk("STALLION: failed to allocate memory (size=%d)\n",
                        sizeof(stlbrd_t));
                return((stlbrd_t *) NULL);
        }

        memset(brdp, 0, sizeof(stlbrd_t));
        brdp->magic = STL_BOARDMAGIC;
        return(brdp);
}

/*****************************************************************************/

static int stl_open(struct tty_struct *tty, struct file *filp)
{
        stlport_t       *portp;
        stlbrd_t        *brdp;

        unsigned int    minordev;
        int             brdnr, panelnr, portnr, rc;

#if DEBUG
        printk("stl_open(tty=%x,filp=%x): device=%x\n", (int) tty,
                (int) filp, tty->device);
#endif

        minordev = MINOR(tty->device);
        brdnr = MINOR2BRD(minordev);
        if (brdnr >= stl_nrbrds)
                return(-ENODEV);
        brdp = stl_brds[brdnr];
        if (brdp == (stlbrd_t *) NULL)
                return(-ENODEV);
        minordev = MINOR2PORT(minordev);
        for (portnr = -1, panelnr = 0; (panelnr < STL_MAXPANELS); panelnr++) {
                if (brdp->panels[panelnr] == (stlpanel_t *) NULL)
                        break;
                if (minordev < brdp->panels[panelnr]->nrports) {
                        portnr = minordev;
                        break;
                }
                minordev -= brdp->panels[panelnr]->nrports;
        }
        if (portnr < 0)
                return(-ENODEV);

        portp = brdp->panels[panelnr]->ports[portnr];
        if (portp == (stlport_t *) NULL)
                return(-ENODEV);

        MOD_INC_USE_COUNT;

/*
 *      On the first open of the device setup the port hardware, and
 *      initialize the per port data structure.
 */
        portp->tty = tty;
        tty->driver_data = portp;
        portp->refcount++;

        if ((portp->flags & ASYNC_INITIALIZED) == 0) {
                if (portp->tx.buf == (char *) NULL) {
                        portp->tx.buf = (char *) stl_memalloc(STL_TXBUFSIZE);
                        if (portp->tx.buf == (char *) NULL)
                                return(-ENOMEM);
                        portp->tx.head = portp->tx.buf;
                        portp->tx.tail = portp->tx.buf;
                }
                stl_setport(portp, tty->termios);
                portp->sigs = stl_getsignals(portp);
                stl_setsignals(portp, 1, 1);
                stl_enablerxtx(portp, 1, 1);
                stl_startrxtx(portp, 1, 0);
                clear_bit(TTY_IO_ERROR, &tty->flags);
                portp->flags |= ASYNC_INITIALIZED;
        }

/*
 *      Check if this port is in the middle of closing. If so then wait
 *      until it is closed then return error status, based on flag settings.
 *      The sleep here does not need interrupt protection since the wakeup
 *      for it is done with the same context.
 */
        if (portp->flags & ASYNC_CLOSING) {
                interruptible_sleep_on(&portp->close_wait);
                if (portp->flags & ASYNC_HUP_NOTIFY)
                        return(-EAGAIN);
                return(-ERESTARTSYS);
        }

/*
 *      Based on type of open being done check if it can overlap with any
 *      previous opens still in effect. If we are a normal serial device
 *      then also we might have to wait for carrier.
 */
        if (tty->driver.subtype == STL_DRVTYPCALLOUT) {
                if (portp->flags & ASYNC_NORMAL_ACTIVE)
                        return(-EBUSY);
                if (portp->flags & ASYNC_CALLOUT_ACTIVE) {
                        if ((portp->flags & ASYNC_SESSION_LOCKOUT) &&
                            (portp->session != current->session))
                                return(-EBUSY);
                        if ((portp->flags & ASYNC_PGRP_LOCKOUT) &&
                            (portp->pgrp != current->pgrp))
                                return(-EBUSY);
                }
                portp->flags |= ASYNC_CALLOUT_ACTIVE;
        } else {
                if (filp->f_flags & O_NONBLOCK) {
                        if (portp->flags & ASYNC_CALLOUT_ACTIVE)
                                return(-EBUSY);
                } else {
                        if ((rc = stl_waitcarrier(portp, filp)) != 0)
                                return(rc);
                }
                portp->flags |= ASYNC_NORMAL_ACTIVE;
        }

        if ((portp->refcount == 1) && (portp->flags & ASYNC_SPLIT_TERMIOS)) {
                if (tty->driver.subtype == STL_DRVTYPSERIAL)
                        *tty->termios = portp->normaltermios;
                else
                        *tty->termios = portp->callouttermios;
                stl_setport(portp, tty->termios);
        }

        portp->session = current->session;
        portp->pgrp = current->pgrp;
        return(0);
}

/*****************************************************************************/

/*
 *      Possibly need to wait for carrier (DCD signal) to come high. Say
 *      maybe because if we are clocal then we don't need to wait...
 */

static int stl_waitcarrier(stlport_t *portp, struct file *filp)
{
        unsigned long   flags;
        int             rc, doclocal;

#if DEBUG
        printk("stl_waitcarrier(portp=%x,filp=%x)\n", (int) portp, (int) filp);
#endif

        rc = 0;
        doclocal = 0;

        if (portp->flags & ASYNC_CALLOUT_ACTIVE) {
                if (portp->normaltermios.c_cflag & CLOCAL)
                        doclocal++;
        } else {
                if (portp->tty->termios->c_cflag & CLOCAL)
                        doclocal++;
        }

        save_flags(flags);
        cli();
        portp->openwaitcnt++;
        if (! tty_hung_up_p(filp))
                portp->refcount--;

        for (;;) {
                if ((portp->flags & ASYNC_CALLOUT_ACTIVE) == 0)
                        stl_setsignals(portp, 1, 1);
                if (tty_hung_up_p(filp) ||
                    ((portp->flags & ASYNC_INITIALIZED) == 0)) {
                        if (portp->flags & ASYNC_HUP_NOTIFY)
                                rc = -EBUSY;
                        else
                                rc = -ERESTARTSYS;
                        break;
                }
                if (((portp->flags & ASYNC_CALLOUT_ACTIVE) == 0) &&
                    ((portp->flags & ASYNC_CLOSING) == 0) &&
                    (doclocal || (portp->sigs & TIOCM_CD))) {
                        break;
                }
                if (signal_pending(current)) {
                        rc = -ERESTARTSYS;
                        break;
                }
                interruptible_sleep_on(&portp->open_wait);
        }

        if (! tty_hung_up_p(filp))
                portp->refcount++;
        portp->openwaitcnt--;
        restore_flags(flags);

        return(rc);
}

/*****************************************************************************/

static void stl_close(struct tty_struct *tty, struct file *filp)
{
        stlport_t       *portp;
        unsigned long   flags;

#if DEBUG
        printk("stl_close(tty=%x,filp=%x)\n", (int) tty, (int) filp);
#endif

        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;

        save_flags(flags);
        cli();
        if (tty_hung_up_p(filp)) {
                MOD_DEC_USE_COUNT;
                restore_flags(flags);
                return;
        }
        if ((tty->count == 1) && (portp->refcount != 1))
                portp->refcount = 1;
        if (portp->refcount-- > 1) {
                MOD_DEC_USE_COUNT;
                restore_flags(flags);
                return;
        }

        portp->refcount = 0;
        portp->flags |= ASYNC_CLOSING;

        if (portp->flags & ASYNC_NORMAL_ACTIVE)
                portp->normaltermios = *tty->termios;
        if (portp->flags & ASYNC_CALLOUT_ACTIVE)
                portp->callouttermios = *tty->termios;

/*
 *      May want to wait for any data to drain before closing. The BUSY
 *      flag keeps track of whether we are still sending or not - it is
 *      very accurate for the cd1400, not quite so for the sc26198.
 *      (The sc26198 has no "end-of-data" interrupt only empty FIFO)
 */
        tty->closing = 1;
        if (portp->closing_wait != ASYNC_CLOSING_WAIT_NONE)
                tty_wait_until_sent(tty, portp->closing_wait);
        stl_waituntilsent(tty, (HZ / 2));

        portp->flags &= ~ASYNC_INITIALIZED;
        stl_disableintrs(portp);
        if (tty->termios->c_cflag & HUPCL)
                stl_setsignals(portp, 0, 0);
        stl_enablerxtx(portp, 0, 0);
        stl_flushbuffer(tty);
        portp->istate = 0;
        if (portp->tx.buf != (char *) NULL) {
                kfree(portp->tx.buf);
                portp->tx.buf = (char *) NULL;
                portp->tx.head = (char *) NULL;
                portp->tx.tail = (char *) NULL;
        }
        set_bit(TTY_IO_ERROR, &tty->flags);
        tty_ldisc_flush(tty);

        tty->closing = 0;
        portp->tty = (struct tty_struct *) NULL;

        if (portp->openwaitcnt) {
                if (portp->close_delay)
                        stl_delay(portp->close_delay);
                wake_up_interruptible(&portp->open_wait);
        }

        portp->flags &= ~(ASYNC_CALLOUT_ACTIVE | ASYNC_NORMAL_ACTIVE |
                ASYNC_CLOSING);
        wake_up_interruptible(&portp->close_wait);
        MOD_DEC_USE_COUNT;
        restore_flags(flags);
}

/*****************************************************************************/

/*
 *      Wait for a specified delay period, this is not a busy-loop. It will
 *      give up the processor while waiting. Unfortunately this has some
 *      rather intimate knowledge of the process management stuff.
 */

static void stl_delay(int len)
{
#if DEBUG
        printk("stl_delay(len=%d)\n", len);
#endif
        if (len > 0) {
                current->state = TASK_INTERRUPTIBLE;
                schedule_timeout(len);
                current->state = TASK_RUNNING;
        }
}

/*****************************************************************************/

/*
 *      Write routine. Take data and stuff it in to the TX ring queue.
 *      If transmit interrupts are not running then start them.
 */

static int stl_write(struct tty_struct *tty, int from_user, const unsigned char *buf, int count)
{
        stlport_t       *portp;
        unsigned int    len, stlen;
        unsigned char   *chbuf;
        char            *head, *tail;

#if DEBUG
        printk("stl_write(tty=%x,from_user=%d,buf=%x,count=%d)\n",
                (int) tty, from_user, (int) buf, count);
#endif

        if ((tty == (struct tty_struct *) NULL) ||
            (stl_tmpwritebuf == (char *) NULL))
                return(0);
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return(0);
        if (portp->tx.buf == (char *) NULL)
                return(0);

/*
 *      If copying direct from user space we must cater for page faults,
 *      causing us to "sleep" here for a while. To handle this copy in all
 *      the data we need now, into a local buffer. Then when we got it all
 *      copy it into the TX buffer.
 */
        chbuf = (unsigned char *) buf;
        if (from_user) {
                head = portp->tx.head;
                tail = portp->tx.tail;
                len = (head >= tail) ? (STL_TXBUFSIZE - (head - tail) - 1) :
                        (tail - head - 1);
                count = MIN(len, count);
                
                down(&stl_tmpwritesem);
                copy_from_user(stl_tmpwritebuf, chbuf, count);
                chbuf = &stl_tmpwritebuf[0];
        }

        head = portp->tx.head;
        tail = portp->tx.tail;
        if (head >= tail) {
                len = STL_TXBUFSIZE - (head - tail) - 1;
                stlen = STL_TXBUFSIZE - (head - portp->tx.buf);
        } else {
                len = tail - head - 1;
                stlen = len;
        }

        len = MIN(len, count);
        count = 0;
        while (len > 0) {
                stlen = MIN(len, stlen);
                memcpy(head, chbuf, stlen);
                len -= stlen;
                chbuf += stlen;
                count += stlen;
                head += stlen;
                if (head >= (portp->tx.buf + STL_TXBUFSIZE)) {
                        head = portp->tx.buf;
                        stlen = tail - head;
                }
        }
        portp->tx.head = head;

        clear_bit(ASYI_TXLOW, &portp->istate);
        stl_startrxtx(portp, -1, 1);

        if (from_user)
                up(&stl_tmpwritesem);

        return(count);
}

/*****************************************************************************/

static void stl_putchar(struct tty_struct *tty, unsigned char ch)
{
        stlport_t       *portp;
        unsigned int    len;
        char            *head, *tail;

#if DEBUG
        printk("stl_putchar(tty=%x,ch=%x)\n", (int) tty, (int) ch);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;
        if (portp->tx.buf == (char *) NULL)
                return;

        head = portp->tx.head;
        tail = portp->tx.tail;

        len = (head >= tail) ? (STL_TXBUFSIZE - (head - tail)) : (tail - head);
        len--;

        if (len > 0) {
                *head++ = ch;
                if (head >= (portp->tx.buf + STL_TXBUFSIZE))
                        head = portp->tx.buf;
        }       
        portp->tx.head = head;
}

/*****************************************************************************/

/*
 *      If there are any characters in the buffer then make sure that TX
 *      interrupts are on and get'em out. Normally used after the putchar
 *      routine has been called.
 */

static void stl_flushchars(struct tty_struct *tty)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_flushchars(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;
        if (portp->tx.buf == (char *) NULL)
                return;

#if 0
        if (tty->stopped || tty->hw_stopped ||
            (portp->tx.head == portp->tx.tail))
                return;
#endif
        stl_startrxtx(portp, -1, 1);
}

/*****************************************************************************/

static int stl_writeroom(struct tty_struct *tty)
{
        stlport_t       *portp;
        char            *head, *tail;

#if DEBUG
        printk("stl_writeroom(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return(0);
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return(0);
        if (portp->tx.buf == (char *) NULL)
                return(0);

        head = portp->tx.head;
        tail = portp->tx.tail;
        return((head >= tail) ? (STL_TXBUFSIZE - (head - tail) - 1) : (tail - head - 1));
}

/*****************************************************************************/

/*
 *      Return number of chars in the TX buffer. Normally we would just
 *      calculate the number of chars in the buffer and return that, but if
 *      the buffer is empty and TX interrupts are still on then we return
 *      that the buffer still has 1 char in it. This way whoever called us
 *      will not think that ALL chars have drained - since the UART still
 *      must have some chars in it (we are busy after all).
 */

static int stl_charsinbuffer(struct tty_struct *tty)
{
        stlport_t       *portp;
        unsigned int    size;
        char            *head, *tail;

#if DEBUG
        printk("stl_charsinbuffer(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return(0);
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return(0);
        if (portp->tx.buf == (char *) NULL)
                return(0);

        head = portp->tx.head;
        tail = portp->tx.tail;
        size = (head >= tail) ? (head - tail) : (STL_TXBUFSIZE - (tail - head));
        if ((size == 0) && test_bit(ASYI_TXBUSY, &portp->istate))
                size = 1;
        return(size);
}

/*****************************************************************************/

/*
 *      Generate the serial struct info.
 */

static void stl_getserial(stlport_t *portp, struct serial_struct *sp)
{
        struct serial_struct    sio;
        stlbrd_t                *brdp;

#if DEBUG
        printk("stl_getserial(portp=%x,sp=%x)\n", (int) portp, (int) sp);
#endif

        memset(&sio, 0, sizeof(struct serial_struct));
        sio.line = portp->portnr;
        sio.port = portp->ioaddr;
        sio.flags = portp->flags;
        sio.baud_base = portp->baud_base;
        sio.close_delay = portp->close_delay;
        sio.closing_wait = portp->closing_wait;
        sio.custom_divisor = portp->custom_divisor;
        sio.hub6 = 0;
        if (portp->uartp == &stl_cd1400uart) {
                sio.type = PORT_CIRRUS;
                sio.xmit_fifo_size = CD1400_TXFIFOSIZE;
        } else {
                sio.type = PORT_UNKNOWN;
                sio.xmit_fifo_size = SC26198_TXFIFOSIZE;
        }

        brdp = stl_brds[portp->brdnr];
        if (brdp != (stlbrd_t *) NULL)
                sio.irq = brdp->irq;

        copy_to_user(sp, &sio, sizeof(struct serial_struct));
}

/*****************************************************************************/

/*
 *      Set port according to the serial struct info.
 *      At this point we do not do any auto-configure stuff, so we will
 *      just quietly ignore any requests to change irq, etc.
 */

static int stl_setserial(stlport_t *portp, struct serial_struct *sp)
{
        struct serial_struct    sio;

#if DEBUG
        printk("stl_setserial(portp=%x,sp=%x)\n", (int) portp, (int) sp);
#endif

        if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
                return -EFAULT;
        if (!capable(CAP_SYS_ADMIN)) {
                if ((sio.baud_base != portp->baud_base) ||
                    (sio.close_delay != portp->close_delay) ||
                    ((sio.flags & ~ASYNC_USR_MASK) !=
                    (portp->flags & ~ASYNC_USR_MASK)))
                        return(-EPERM);
        } 

        portp->flags = (portp->flags & ~ASYNC_USR_MASK) |
                (sio.flags & ASYNC_USR_MASK);
        portp->baud_base = sio.baud_base;
        portp->close_delay = sio.close_delay;
        portp->closing_wait = sio.closing_wait;
        portp->custom_divisor = sio.custom_divisor;
        stl_setport(portp, portp->tty->termios);
        return(0);
}

/*****************************************************************************/

static int stl_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
{
        stlport_t       *portp;
        unsigned int    ival;
        int             rc;

#if DEBUG
        printk("stl_ioctl(tty=%x,file=%x,cmd=%x,arg=%x)\n",
                (int) tty, (int) file, cmd, (int) arg);
#endif

        if (tty == (struct tty_struct *) NULL)
                return(-ENODEV);
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return(-ENODEV);

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

        rc = 0;

        switch (cmd) {
        case TIOCGSOFTCAR:
                rc = put_user(((tty->termios->c_cflag & CLOCAL) ? 1 : 0),
                        (unsigned int *) arg);
                break;
        case TIOCSSOFTCAR:
                if ((rc = verify_area(VERIFY_READ, (void *) arg,
                    sizeof(int))) == 0) {
                        get_user(ival, (unsigned int *) arg);
                        tty->termios->c_cflag =
                                (tty->termios->c_cflag & ~CLOCAL) |
                                (ival ? CLOCAL : 0);
                }
                break;
        case TIOCMGET:
                if ((rc = verify_area(VERIFY_WRITE, (void *) arg,
                    sizeof(unsigned int))) == 0) {
                        ival = stl_getsignals(portp);
                        put_user(ival, (unsigned int *) arg);
                }
                break;
        case TIOCMBIS:
                if ((rc = verify_area(VERIFY_READ, (void *) arg,
                    sizeof(unsigned int))) == 0) {
                        get_user(ival, (unsigned int *) arg);
                        stl_setsignals(portp, ((ival & TIOCM_DTR) ? 1 : -1),
                                ((ival & TIOCM_RTS) ? 1 : -1));
                }
                break;
        case TIOCMBIC:
                if ((rc = verify_area(VERIFY_READ, (void *) arg,
                    sizeof(unsigned int))) == 0) {
                        get_user(ival, (unsigned int *) arg);
                        stl_setsignals(portp, ((ival & TIOCM_DTR) ? 0 : -1),
                                ((ival & TIOCM_RTS) ? 0 : -1));
                }
                break;
        case TIOCMSET:
                if ((rc = verify_area(VERIFY_READ, (void *) arg,
                    sizeof(unsigned int))) == 0) {
                        get_user(ival, (unsigned int *) arg);
                        stl_setsignals(portp, ((ival & TIOCM_DTR) ? 1 : 0),
                                ((ival & TIOCM_RTS) ? 1 : 0));
                }
                break;
        case TIOCGSERIAL:
                if ((rc = verify_area(VERIFY_WRITE, (void *) arg,
                    sizeof(struct serial_struct))) == 0)
                        stl_getserial(portp, (struct serial_struct *) arg);
                break;
        case TIOCSSERIAL:
                if ((rc = verify_area(VERIFY_READ, (void *) arg,
                    sizeof(struct serial_struct))) == 0)
                        rc = stl_setserial(portp, (struct serial_struct *) arg);
                break;
        case COM_GETPORTSTATS:
                if ((rc = verify_area(VERIFY_WRITE, (void *) arg,
                    sizeof(comstats_t))) == 0)
                        rc = stl_getportstats(portp, (comstats_t *) arg);
                break;
        case COM_CLRPORTSTATS:
                if ((rc = verify_area(VERIFY_WRITE, (void *) arg,
                    sizeof(comstats_t))) == 0)
                        rc = stl_clrportstats(portp, (comstats_t *) arg);
                break;
        case TIOCSERCONFIG:
        case TIOCSERGWILD:
        case TIOCSERSWILD:
        case TIOCSERGETLSR:
        case TIOCSERGSTRUCT:
        case TIOCSERGETMULTI:
        case TIOCSERSETMULTI:
        default:
                rc = -ENOIOCTLCMD;
                break;
        }

        return(rc);
}

/*****************************************************************************/

static void stl_settermios(struct tty_struct *tty, struct termios *old)
{
        stlport_t       *portp;
        struct termios  *tiosp;

#if DEBUG
        printk("stl_settermios(tty=%x,old=%x)\n", (int) tty, (int) old);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;

        tiosp = tty->termios;
        if ((tiosp->c_cflag == old->c_cflag) &&
            (tiosp->c_iflag == old->c_iflag))
                return;

        stl_setport(portp, tiosp);
        stl_setsignals(portp, ((tiosp->c_cflag & (CBAUD & ~CBAUDEX)) ? 1 : 0),
                -1);
        if ((old->c_cflag & CRTSCTS) && ((tiosp->c_cflag & CRTSCTS) == 0)) {
                tty->hw_stopped = 0;
                stl_start(tty);
        }
        if (((old->c_cflag & CLOCAL) == 0) && (tiosp->c_cflag & CLOCAL))
                wake_up_interruptible(&portp->open_wait);
}

/*****************************************************************************/

/*
 *      Attempt to flow control who ever is sending us data. Based on termios
 *      settings use software or/and hardware flow control.
 */

static void stl_throttle(struct tty_struct *tty)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_throttle(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;
        stl_flowctrl(portp, 0);
}

/*****************************************************************************/

/*
 *      Unflow control the device sending us data...
 */

static void stl_unthrottle(struct tty_struct *tty)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_unthrottle(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;
        stl_flowctrl(portp, 1);
}

/*****************************************************************************/

/*
 *      Stop the transmitter. Basically to do this we will just turn TX
 *      interrupts off.
 */

static void stl_stop(struct tty_struct *tty)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_stop(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;
        stl_startrxtx(portp, -1, 0);
}

/*****************************************************************************/

/*
 *      Start the transmitter again. Just turn TX interrupts back on.
 */

static void stl_start(struct tty_struct *tty)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_start(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;
        stl_startrxtx(portp, -1, 1);
}

/*****************************************************************************/

/*
 *      Hangup this port. This is pretty much like closing the port, only
 *      a little more brutal. No waiting for data to drain. Shutdown the
 *      port and maybe drop signals.
 */

static void stl_hangup(struct tty_struct *tty)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_hangup(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;

        portp->flags &= ~ASYNC_INITIALIZED;
        stl_disableintrs(portp);
        if (tty->termios->c_cflag & HUPCL)
                stl_setsignals(portp, 0, 0);
        stl_enablerxtx(portp, 0, 0);
        stl_flushbuffer(tty);
        portp->istate = 0;
        set_bit(TTY_IO_ERROR, &tty->flags);
        if (portp->tx.buf != (char *) NULL) {
                kfree(portp->tx.buf);
                portp->tx.buf = (char *) NULL;
                portp->tx.head = (char *) NULL;
                portp->tx.tail = (char *) NULL;
        }
        portp->tty = (struct tty_struct *) NULL;
        portp->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CALLOUT_ACTIVE);
        portp->refcount = 0;
        wake_up_interruptible(&portp->open_wait);
}

/*****************************************************************************/

static void stl_flushbuffer(struct tty_struct *tty)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_flushbuffer(tty=%x)\n", (int) tty);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;

        stl_flush(portp);
        tty_wakeup(tty);
}

/*****************************************************************************/

static void stl_breakctl(struct tty_struct *tty, int state)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_breakctl(tty=%x,state=%d)\n", (int) tty, state);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;

        stl_sendbreak(portp, ((state == -1) ? 1 : 2));
}

/*****************************************************************************/

static void stl_waituntilsent(struct tty_struct *tty, int timeout)
{
        stlport_t       *portp;
        unsigned long   tend;

#if DEBUG
        printk("stl_waituntilsent(tty=%x,timeout=%d)\n", (int) tty, timeout);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;

        if (timeout == 0)
                timeout = HZ;
        tend = jiffies + timeout;

        while (stl_datastate(portp)) {
                if (signal_pending(current))
                        break;
                stl_delay(2);
                if (time_after_eq(jiffies, tend))
                        break;
        }
}

/*****************************************************************************/

static void stl_sendxchar(struct tty_struct *tty, char ch)
{
        stlport_t       *portp;

#if DEBUG
        printk("stl_sendxchar(tty=%x,ch=%x)\n", (int) tty, ch);
#endif

        if (tty == (struct tty_struct *) NULL)
                return;
        portp = tty->driver_data;
        if (portp == (stlport_t *) NULL)
                return;

        if (ch == STOP_CHAR(tty))
                stl_sendflow(portp, 0);
        else if (ch == START_CHAR(tty))
                stl_sendflow(portp, 1);
        else
                stl_putchar(tty, ch);
}

/*****************************************************************************/

#define MAXLINE         80

/*
 *      Format info for a specified port. The line is deliberately limited
 *      to 80 characters. (If it is too long it will be truncated, if too
 *      short then padded with spaces).
 */

static int stl_portinfo(stlport_t *portp, int portnr, char *pos)
{
        char    *sp;
        int     sigs, cnt;

        sp = pos;
        sp += sprintf(sp, "%d: uart:%s tx:%d rx:%d",
                portnr, (portp->hwid == 1) ? "SC26198" : "CD1400",
                (int) portp->stats.txtotal, (int) portp->stats.rxtotal);

        if (portp->stats.rxframing)
                sp += sprintf(sp, " fe:%d", (int) portp->stats.rxframing);
        if (portp->stats.rxparity)
                sp += sprintf(sp, " pe:%d", (int) portp->stats.rxparity);
        if (portp->stats.rxbreaks)
                sp += sprintf(sp, " brk:%d", (int) portp->stats.rxbreaks);
        if (portp->stats.rxoverrun)
                sp += sprintf(sp, " oe:%d", (int) portp->stats.rxoverrun);

        sigs = stl_getsignals(portp);
        cnt = sprintf(sp, "%s%s%s%s%s ",
                (sigs & TIOCM_RTS) ? "|RTS" : "",
                (sigs & TIOCM_CTS) ? "|CTS" : "",
                (sigs & TIOCM_DTR) ? "|DTR" : "",
                (sigs & TIOCM_CD) ? "|DCD" : "",
                (sigs & TIOCM_DSR) ? "|DSR" : "");
        *sp = ' ';
        sp += cnt;

        for (cnt = (sp - pos); (cnt < (MAXLINE - 1)); cnt++)
                *sp++ = ' ';
        if (cnt >= MAXLINE)
                pos[(MAXLINE - 2)] = '+';
        pos[(MAXLINE - 1)] = '\n';

        return(MAXLINE);
}

/*****************************************************************************/

/*
 *      Port info, read from the /proc file system.
 */

static int stl_readproc(char *page, char **start, off_t off, int count, int *eof, void *data)
{
        stlbrd_t        *brdp;
        stlpanel_t      *panelp;
        stlport_t       *portp;
        int             brdnr, panelnr, portnr, totalport;
        int             curoff, maxoff;
        char            *pos;

#if DEBUG
        printk("stl_readproc(page=%x,start=%x,off=%x,count=%d,eof=%x,"
                "data=%x\n", (int) page, (int) start, (int) off, count,
                (int) eof, (int) data);
#endif

        pos = page;
        totalport = 0;
        curoff = 0;

        if (off == 0) {
                pos += sprintf(pos, "%s: version %s", stl_drvtitle,
                        stl_drvversion);
                while (pos < (page + MAXLINE - 1))
                        *pos++ = ' ';
                *pos++ = '\n';
        }
        curoff =  MAXLINE;

/*
 *      We scan through for each board, panel and port. The offset is
 *      calculated on the fly, and irrelevant ports are skipped.
 */
        for (brdnr = 0; (brdnr < stl_nrbrds); brdnr++) {
                brdp = stl_brds[brdnr];
                if (brdp == (stlbrd_t *) NULL)
                        continue;
                if (brdp->state == 0)
                        continue;

                maxoff = curoff + (brdp->nrports * MAXLINE);
                if (off >= maxoff) {
                        curoff = maxoff;
                        continue;
                }

                totalport = brdnr * STL_MAXPORTS;
                for (panelnr = 0; (panelnr < brdp->nrpanels); panelnr++) {
                        panelp = brdp->panels[panelnr];
                        if (panelp == (stlpanel_t *) NULL)
                                continue;

                        maxoff = curoff + (panelp->nrports * MAXLINE);
                        if (off >= maxoff) {
                                curoff = maxoff;
                                totalport += panelp->nrports;
                                continue;
                        }

                        for (portnr = 0; (portnr < panelp->nrports); portnr++,
                            totalport++) {
                                portp = panelp->ports[portnr];
                                if (portp == (stlport_t *) NULL)
                                        continue;
                                if (off >= (curoff += MAXLINE))
                                        continue;
                                if ((pos - page + MAXLINE) > count)
                                        goto stl_readdone;
                                pos += stl_portinfo(portp, totalport, pos);
                        }
                }
        }

        *eof = 1;

stl_readdone:
        *start = page;
        return(pos - page);
}

/*****************************************************************************/

/*
 *      All board interrupts are vectored through here first. This code then
 *      calls off to the approrpriate board interrupt handlers.
 */

static void stl_intr(int irq, void *dev_id, struct pt_regs *regs)
{
        stlbrd_t        *brdp;

#if DEBUG
        printk("stl_intr(irq=%d,regs=%x)\n", irq, (int) regs);
#endif
        brdp = (stlbrd_t *) dev_id;
        (* brdp->isr)(brdp);
}

/*****************************************************************************/

/*
 *      Interrupt service routine for EasyIO board types.
 */

static void stl_eiointr(stlbrd_t *brdp)
{
        stlpanel_t      *panelp;
        unsigned int    iobase;

        panelp = brdp->panels[0];
        iobase = panelp->iobase;
        while (inb(brdp->iostatus) & EIO_INTRPEND)
                (* panelp->isr)(panelp, iobase);
}

/*****************************************************************************/

/*
 *      Interrupt service routine for ECH-AT board types.
 */

static void stl_echatintr(stlbrd_t *brdp)
{
        stlpanel_t      *panelp;
        unsigned int    ioaddr;
        int             bnknr;

        outb((brdp->ioctrlval | ECH_BRDENABLE), brdp->ioctrl);

        while (inb(brdp->iostatus) & ECH_INTRPEND) {
                for (bnknr = 0; (bnknr < brdp->nrbnks); bnknr++) {
                        ioaddr = brdp->bnkstataddr[bnknr];
                        if (inb(ioaddr) & ECH_PNLINTRPEND) {
                                panelp = brdp->bnk2panel[bnknr];
                                (* panelp->isr)(panelp, (ioaddr & 0xfffc));
                        }
                }
        }

        outb((brdp->ioctrlval | ECH_BRDDISABLE), brdp->ioctrl);
}

/*****************************************************************************/

/*
 *      Interrupt service routine for ECH-MCA board types.
 */

static void stl_echmcaintr(stlbrd_t *brdp)
{
        stlpanel_t      *panelp;
        unsigned int    ioaddr;
        int             bnknr;

        while (inb(brdp->iostatus) & ECH_INTRPEND) {
                for (bnknr = 0; (bnknr < brdp->nrbnks); bnknr++) {
                        ioaddr = brdp->bnkstataddr[bnknr];
                        if (inb(ioaddr) & ECH_PNLINTRPEND) {
                                panelp = brdp->bnk2panel[bnknr];
                                (* panelp->isr)(panelp, (ioaddr & 0xfffc));
                        }
                }
        }
}

/*****************************************************************************/

/*
 *      Interrupt service routine for ECH-PCI board types.
 */

static void stl_echpciintr(stlbrd_t *brdp)
{
        stlpanel_t      *panelp;
        unsigned int    ioaddr;
        int             bnknr, recheck;

        while (1) {
                recheck = 0;
                for (bnknr = 0; (bnknr < brdp->nrbnks); bnknr++) {
                        outb(brdp->bnkpageaddr[bnknr], brdp->ioctrl);
                        ioaddr = brdp->bnkstataddr[bnknr];
                        if (inb(ioaddr) & ECH_PNLINTRPEND) {
                                panelp = brdp->bnk2panel[bnknr];
                                (* panelp->isr)(panelp, (ioaddr & 0xfffc));
                                recheck++;
                        }
                }
                if (! recheck)
                        break;
        }
}

/*****************************************************************************/

/*
 *      Interrupt service routine for ECH-8/64-PCI board types.
 */

static void stl_echpci64intr(stlbrd_t *brdp)
{
        stlpanel_t      *panelp;
        unsigned int    ioaddr;
        int             bnknr;

        while (inb(brdp->ioctrl) & 0x1) {
                for (bnknr = 0; (bnknr < brdp->nrbnks); bnknr++) {
                        ioaddr = brdp->bnkstataddr[bnknr];
                        if (inb(ioaddr) & ECH_PNLINTRPEND) {
                                panelp = brdp->bnk2panel[bnknr];
                                (* panelp->isr)(panelp, (ioaddr & 0xfffc));
                        }
                }
        }
}

/*****************************************************************************/

/*
 *      Service an off-level request for some channel.
 */
static void stl_offintr(void *private)
{
        stlport_t               *portp;
        struct tty_struct       *tty;
        unsigned int            oldsigs;

        portp = private;

#if DEBUG
        printk("stl_offintr(portp=%x)\n", (int) portp);
#endif

        if (portp == (stlport_t *) NULL)
                goto out;

        tty = portp->tty;
        if (tty == (struct tty_struct *) NULL)
                goto out;

        lock_kernel();
        if (test_bit(ASYI_TXLOW, &portp->istate)) {
                tty_wakeup(tty);
        }
        if (test_bit(ASYI_DCDCHANGE, &portp->istate)) {
                clear_bit(ASYI_DCDCHANGE, &portp->istate);
                oldsigs = portp->sigs;
                portp->sigs = stl_getsignals(portp);
                if ((portp->sigs & TIOCM_CD) && ((oldsigs & TIOCM_CD) == 0))
                        wake_up_interruptible(&portp->open_wait);
                if ((oldsigs & TIOCM_CD) && ((portp->sigs & TIOCM_CD) == 0)) {
                        if (portp->flags & ASYNC_CHECK_CD) {
                                if (! ((portp->flags & ASYNC_CALLOUT_ACTIVE) &&
                                    (portp->flags & ASYNC_CALLOUT_NOHUP))) {
                                        tty_hangup(tty);        /* FIXME: module removal race here - AKPM */
                                }
                        }
                }
        }
        unlock_kernel();
out:
        MOD_DEC_USE_COUNT;
}

/*****************************************************************************/

/*
 *      Initialize all the ports on a panel.
 */

static int __init stl_initports(stlbrd_t *brdp, stlpanel_t *panelp)
{
        stlport_t       *portp;
        int             chipmask, i;

#if DEBUG
        printk("stl_initports(brdp=%x,panelp=%x)\n", (int) brdp, (int) panelp);
#endif

        chipmask = stl_panelinit(brdp, panelp);

/*
 *      All UART's are initialized (if found!). Now go through and setup
 *      each ports data structures.
 */
        for (i = 0; (i < panelp->nrports); i++) {
                portp = (stlport_t *) stl_memalloc(sizeof(stlport_t));
                if (portp == (stlport_t *) NULL) {
                        printk("STALLION: failed to allocate memory "
                                "(size=%d)\n", sizeof(stlport_t));
                        break;
                }
                memset(portp, 0, sizeof(stlport_t));

                portp->magic = STL_PORTMAGIC;
                portp->portnr = i;
                portp->brdnr = panelp->brdnr;
                portp->panelnr = panelp->panelnr;
                portp->uartp = panelp->uartp;
                portp->clk = brdp->clk;
                portp->baud_base = STL_BAUDBASE;
                portp->close_delay = STL_CLOSEDELAY;
                portp->closing_wait = 30 * HZ;
                portp->normaltermios = stl_deftermios;
                portp->callouttermios = stl_deftermios;
                portp->tqueue.routine = stl_offintr;
                portp->tqueue.data = portp;
                init_waitqueue_head(&portp->open_wait);
                init_waitqueue_head(&portp->close_wait);
                portp->stats.brd = portp->brdnr;
                portp->stats.panel = portp->panelnr;
                portp->stats.port = portp->portnr;
                panelp->ports[i] = portp;
                stl_portinit(brdp, panelp, portp);
        }

        return(0);
}

/*****************************************************************************/

/*
 *      Try to find and initialize an EasyIO board.
 */

static inline int stl_initeio(stlbrd_t *brdp)
{
        stlpanel_t      *panelp;
        unsigned int    status;
        char            *name;

#if DEBUG
        printk("stl_initeio(brdp=%x)\n", (int) brdp);
#endif

        brdp->ioctrl = brdp->ioaddr1 + 1;
        brdp->iostatus = brdp->ioaddr1 + 2;

        status = inb(brdp->iostatus);
        if ((status & EIO_IDBITMASK) == EIO_MK3)
                brdp->ioctrl++;

/*
 *      Handle board specific stuff now. The real difference is PCI
 *      or not PCI.
 */
        if (brdp->brdtype == BRD_EASYIOPCI) {
                brdp->iosize1 = 0x80;
                brdp->iosize2 = 0x80;
                name = "serial(EIO-PCI)";
                outb(0x41, (brdp->ioaddr2 + 0x4c));
        } else {
                brdp->iosize1 = 8;
                name = "serial(EIO)";
                if ((brdp->irq < 0) || (brdp->irq > 15) ||
                    (stl_vecmap[brdp->irq] == (unsigned char) 0xff)) {
                        printk("STALLION: invalid irq=%d for brd=%d\n",
                                brdp->irq, brdp->brdnr);
                        return(-EINVAL);
                }
                outb((stl_vecmap[brdp->irq] | EIO_0WS |
                        ((brdp->irqtype) ? EIO_INTLEVEL : EIO_INTEDGE)),
                        brdp->ioctrl);
        }

        if (check_region(brdp->ioaddr1, brdp->iosize1)) {
                printk("STALLION: Warning, board %d I/O address %x conflicts "
                        "with another device\n", brdp->brdnr, brdp->ioaddr1);
        }
        if (brdp->iosize2 > 0) {
                if (check_region(brdp->ioaddr2, brdp->iosize2)) {
                        printk("STALLION: Warning, board %d I/O address %x "
                                "conflicts with another device\n",
                                brdp->brdnr, brdp->ioaddr2);
                }
        }
 
/*
 *      Everything looks OK, so let's go ahead and probe for the hardware.
 */
        brdp->clk = CD1400_CLK;
        brdp->isr = stl_eiointr;

        switch (status & EIO_IDBITMASK) {
        case EIO_8PORTM:
                brdp->clk = CD1400_CLK8M;
                /* fall thru */
        case EIO_8PORTRS:
        case EIO_8PORTDI:
                brdp->nrports = 8;
                break;
        case EIO_4PORTRS:
                brdp->nrports = 4;
                break;
        case EIO_MK3:
                switch (status & EIO_BRDMASK) {
                case ID_BRD4:
                        brdp->nrports = 4;
                        break;
                case ID_BRD8:
                        brdp->nrports = 8;
                        break;
                case ID_BRD16:
                        brdp->nrports = 16;
                        break;
                default:
                        return(-ENODEV);
                }
                break;
        default:
                return(-ENODEV);
        }

/*
 *      We have verfied that the board is actually present, so now we
 *      can complete the setup.
 */
        request_region(brdp->ioaddr1, brdp->iosize1, name);
        if (brdp->iosize2 > 0)
                request_region(brdp->ioaddr2, brdp->iosize2, name);

        panelp = (stlpanel_t *) stl_memalloc(sizeof(stlpanel_t));
        if (panelp == (stlpanel_t *) NULL) {
                printk("STALLION: failed to allocate memory (size=%d)\n",
                        sizeof(stlpanel_t));
                return(-ENOMEM);
        }
        memset(panelp, 0, sizeof(stlpanel_t));

        panelp->magic = STL_PANELMAGIC;
        panelp->brdnr = brdp->brdnr;
        panelp->panelnr = 0;
        panelp->nrports = brdp->nrports;
        panelp->iobase = brdp->ioaddr1;
        panelp->hwid = status;
        if ((status & EIO_IDBITMASK) == EIO_MK3) {
                panelp->uartp = (void *) &stl_sc26198uart;
                panelp->isr = stl_sc26198intr;
        } else {
                panelp->uartp = (void *) &stl_cd1400uart;
                panelp->isr = stl_cd1400eiointr;
        }

        brdp->panels[0] = panelp;
        brdp->nrpanels = 1;
        brdp->state |= BRD_FOUND;
        brdp->hwid = status;
        if (request_irq(brdp->irq, stl_intr, SA_SHIRQ, name, brdp) != 0) {
                printk("STALLION: failed to register interrupt "
                       "routine for %s irq=%d\n", name, brdp->irq);
                return -ENODEV;
        }

        return 0;
}

/*****************************************************************************/

/*
 *      Try to find an ECH board and initialize it. This code is capable of
 *      dealing with all types of ECH board.
 */

static int inline stl_initech(stlbrd_t *brdp)
{
        stlpanel_t      *panelp;
        unsigned int    status, nxtid, ioaddr, conflict;
        int             panelnr, banknr, i;
        char            *name;

#if DEBUG
        printk("stl_initech(brdp=%x)\n", (int) brdp);
#endif

        status = 0;
        conflict = 0;

/*
 *      Set up the initial board register contents for boards. This varies a
 *      bit between the different board types. So we need to handle each
 *      separately. Also do a check that the supplied IRQ is good.
 */
        switch (brdp->brdtype) {

        case BRD_ECH:
                brdp->isr = stl_echatintr;
                brdp->ioctrl = brdp->ioaddr1 + 1;
                brdp->iostatus = brdp->ioaddr1 + 1;
                status = inb(brdp->iostatus);
                if ((status & ECH_IDBITMASK) != ECH_ID)
                        return(-ENODEV);
                if ((brdp->irq < 0) || (brdp->irq > 15) ||
                    (stl_vecmap[brdp->irq] == (unsigned char) 0xff)) {
                        printk("STALLION: invalid irq=%d for brd=%d\n",
                                brdp->irq, brdp->brdnr);
                        return(-EINVAL);
                }
                status = ((brdp->ioaddr2 & ECH_ADDR2MASK) >> 1);
                status |= (stl_vecmap[brdp->irq] << 1);
                outb((status | ECH_BRDRESET), brdp->ioaddr1);
                brdp->ioctrlval = ECH_INTENABLE |
                        ((brdp->irqtype) ? ECH_INTLEVEL : ECH_INTEDGE);
                for (i = 0; (i < 10); i++)
                        outb((brdp->ioctrlval | ECH_BRDENABLE), brdp->ioctrl);
                brdp->iosize1 = 2;
                brdp->iosize2 = 32;
                name = "serial(EC8/32)";
                outb(status, brdp->ioaddr1);
                break;

        case BRD_ECHMC:
                brdp->isr = stl_echmcaintr;
                brdp->ioctrl = brdp->ioaddr1 + 0x20;
                brdp->iostatus = brdp->ioctrl;
                status = inb(brdp->iostatus);
                if ((status & ECH_IDBITMASK) != ECH_ID)
                        return(-ENODEV);
                if ((brdp->irq < 0) || (brdp->irq > 15) ||
                    (stl_vecmap[brdp->irq] == (unsigned char) 0xff)) {
                        printk("STALLION: invalid irq=%d for brd=%d\n",
                                brdp->irq, brdp->brdnr);
                        return(-EINVAL);
                }
                outb(ECHMC_BRDRESET, brdp->ioctrl);
                outb(ECHMC_INTENABLE, brdp->ioctrl);
                brdp->iosize1 = 64;
                name = "serial(EC8/32-MC)";
                break;

        case BRD_ECHPCI:
                brdp->isr = stl_echpciintr;
                brdp->ioctrl = brdp->ioaddr1 + 2;
                brdp->iosize1 = 4;
                brdp->iosize2 = 8;
                name = "serial(EC8/32-PCI)";
                break;

        case BRD_ECH64PCI:
                brdp->isr = stl_echpci64intr;
                brdp->ioctrl = brdp->ioaddr2 + 0x40;
                outb(0x43, (brdp->ioaddr1 + 0x4c));
                brdp->iosize1 = 0x80;
                brdp->iosize2 = 0x80;
                name = "serial(EC8/64-PCI)";
                break;

        default:
                printk("STALLION: unknown board type=%d\n", brdp->brdtype);
                return(-EINVAL);
                break;
        }

/*
 *      Check boards for possible IO address conflicts. We won't actually
 *      do anything about it here, just issue a warning...
 */
        conflict = check_region(brdp->ioaddr1, brdp->iosize1) ?
                brdp->ioaddr1 : 0;
        if ((conflict == 0) && (brdp->iosize2 > 0))
                conflict = check_region(brdp->ioaddr2, brdp->iosize2) ?
                        brdp->ioaddr2 : 0;
        if (conflict) {
                printk("STALLION: Warning, board %d I/O address %x conflicts "
                        "with another device\n", brdp->brdnr, conflict);
        }

        request_region(brdp->ioaddr1, brdp->iosize1, name);
        if (brdp->iosize2 > 0)
                request_region(brdp->ioaddr2, brdp->iosize2, name);

/*
 *      Scan through the secondary io address space looking for panels.
 *      As we find'em allocate and initialize panel structures for each.
 */
        brdp->clk = CD1400_CLK;
        brdp->hwid = status;

        ioaddr = brdp->ioaddr2;
        banknr = 0;
        panelnr = 0;
        nxtid = 0;

        for (i = 0; (i < STL_MAXPANELS); i++) {
                if (brdp->brdtype == BRD_ECHPCI) {
                        outb(nxtid, brdp->ioctrl);
                        ioaddr = brdp->ioaddr2;
                }
                status = inb(ioaddr + ECH_PNLSTATUS);
                if ((status & ECH_PNLIDMASK) != nxtid)
                        break;
                panelp = (stlpanel_t *) stl_memalloc(sizeof(stlpanel_t));
                if (panelp == (stlpanel_t *) NULL) {
                        printk("STALLION: failed to allocate memory "
                                "(size=%d)\n", sizeof(stlpanel_t));
                        break;
                }
                memset(panelp, 0, sizeof(stlpanel_t));
                panelp->magic = STL_PANELMAGIC;
                panelp->brdnr = brdp->brdnr;
                panelp->panelnr = panelnr;
                panelp->iobase = ioaddr;
                panelp->pagenr = nxtid;
                panelp->hwid = status;
                brdp->bnk2panel[banknr] = panelp;
                brdp->bnkpageaddr[banknr] = nxtid;
                brdp->bnkstataddr[banknr++] = ioaddr + ECH_PNLSTATUS;

                if (status & ECH_PNLXPID) {
                        panelp->uartp = (void *) &stl_sc26198uart;
                        panelp->isr = stl_sc26198intr;
                        if (status & ECH_PNL16PORT) {
                                panelp->nrports = 16;
                                brdp->bnk2panel[banknr] = panelp;
                                brdp->bnkpageaddr[banknr] = nxtid;
                                brdp->bnkstataddr[banknr++] = ioaddr + 4 +
                                        ECH_PNLSTATUS;
                        } else {
                                panelp->nrports = 8;
                        }
                } else {
                        panelp->uartp = (void *) &stl_cd1400uart;
                        panelp->isr = stl_cd1400echintr;
                        if (status & ECH_PNL16PORT) {
                                panelp->nrports = 16;
                                panelp->ackmask = 0x80;
                                if (brdp->brdtype != BRD_ECHPCI)
                                        ioaddr += EREG_BANKSIZE;
                                brdp->bnk2panel[banknr] = panelp;
                                brdp->bnkpageaddr[banknr] = ++nxtid;
                                brdp->bnkstataddr[banknr++] = ioaddr +
                                        ECH_PNLSTATUS;
                        } else {
                                panelp->nrports = 8;
                                panelp->ackmask = 0xc0;
                        }
                }

                nxtid++;
                ioaddr += EREG_BANKSIZE;
                brdp->nrports += panelp->nrports;
                brdp->panels[panelnr++] = panelp;
                if ((brdp->brdtype != BRD_ECHPCI) &&
                    (ioaddr >= (brdp->ioaddr2 + brdp->iosize2)))
                        break;
        }

        brdp->nrpanels = panelnr;
        brdp->nrbnks = banknr;
        if (brdp->brdtype == BRD_ECH)
                outb((brdp->ioctrlval | ECH_BRDDISABLE), brdp->ioctrl);

        brdp->state |= BRD_FOUND;
        if (request_irq(brdp->irq, stl_intr, SA_SHIRQ, name, brdp) != 0) {
                printk("STALLION: failed to register interrupt "
                       "routine for %s irq=%d\n", name, brdp->irq);
                i = -ENODEV;
        }

        return(i);
}

/*****************************************************************************/

/*
 *      Initialize and configure the specified board.
 *      Scan through all the boards in the configuration and see what we
 *      can find. Handle EIO and the ECH boards a little differently here
 *      since the initial search and setup is very different.
 */

static int __init stl_brdinit(stlbrd_t *brdp)
{
        int     i;

#if DEBUG
        printk("stl_brdinit(brdp=%x)\n", (int) brdp);
#endif

        switch (brdp->brdtype) {
        case BRD_EASYIO:
        case BRD_EASYIOPCI:
                stl_initeio(brdp);
                break;
        case BRD_ECH:
        case BRD_ECHMC:
        case BRD_ECHPCI:
        case BRD_ECH64PCI:
                stl_initech(brdp);
                break;
        default:
                printk("STALLION: board=%d is unknown board type=%d\n",
                        brdp->brdnr, brdp->brdtype);
                return(ENODEV);
        }

        stl_brds[brdp->brdnr] = brdp;
        if ((brdp->state & BRD_FOUND) == 0) {
                printk("STALLION: %s board not found, board=%d io=%x irq=%d\n",
                        stl_brdnames[brdp->brdtype], brdp->brdnr,
                        brdp->ioaddr1, brdp->irq);
                return(ENODEV);
        }

        for (i = 0; (i < STL_MAXPANELS); i++)
                if (brdp->panels[i] != (stlpanel_t *) NULL)
                        stl_initports(brdp, brdp->panels[i]);

        printk("STALLION: %s found, board=%d io=%x irq=%d "
                "nrpanels=%d nrports=%d\n", stl_brdnames[brdp->brdtype],
                brdp->brdnr, brdp->ioaddr1, brdp->irq, brdp->nrpanels,
                brdp->nrports);
        return(0);
}

/*****************************************************************************/

/*
 *      Find the next available board number that is free.
 */

static inline int stl_getbrdnr()
{
        int     i;

        for (i = 0; (i < STL_MAXBRDS); i++) {
                if (stl_brds[i] == (stlbrd_t *) NULL) {
                        if (i >= stl_nrbrds)
                                stl_nrbrds = i + 1;
                        return(i);
                }
        }
        return(-1);
}

/*****************************************************************************/

#ifdef  CONFIG_PCI

/*
 *      We have a Stallion board. Allocate a board structure and
 *      initialize it. Read its IO and IRQ resources from PCI
 *      configuration space.
 */

static inline int stl_initpcibrd(int brdtype, struct pci_dev *devp)
{
        stlbrd_t        *brdp;

#if DEBUG
        printk("stl_initpcibrd(brdtype=%d,busnr=%x,devnr=%x)\n", brdtype,
                devp->bus->number, devp->devfn);
#endif

        if (pci_enable_device(devp))
                return(-EIO);
        if ((brdp = stl_allocbrd()) == (stlbrd_t *) NULL)
                return(-ENOMEM);
        if ((brdp->brdnr = stl_getbrdnr()) < 0) {
                printk("STALLION: too many boards found, "
                        "maximum supported %d\n", STL_MAXBRDS);
                return(0);
        }
        brdp->brdtype = brdtype;

/*
 *      Different Stallion boards use the BAR registers in different ways,
 *      so set up io addresses based on board type.
 */
#if DEBUG
        printk("%s(%d): BAR[]=%x,%x,%x,%x IRQ=%x\n", __FILE__, __LINE__,
                pci_resource_start(devp, 0), pci_resource_start(devp, 1),
                pci_resource_start(devp, 2), pci_resource_start(devp, 3), devp->irq);
#endif

/*
 *      We have all resources from the board, so let's setup the actual
 *      board structure now.
 */
        switch (brdtype) {
        case BRD_ECHPCI:
                brdp->ioaddr2 = pci_resource_start(devp, 0);
                brdp->ioaddr1 = pci_resource_start(devp, 1);
                break;
        case BRD_ECH64PCI:
                brdp->ioaddr2 = pci_resource_start(devp, 2);
                brdp->ioaddr1 = pci_resource_start(devp, 1);
                break;
        case BRD_EASYIOPCI:
                brdp->ioaddr1 = pci_resource_start(devp, 2);
                brdp->ioaddr2 = pci_resource_start(devp, 1);
                break;
        default:
                printk("STALLION: unknown PCI board type=%d\n", brdtype);
                break;
        }

        brdp->irq = devp->irq;
        stl_brdinit(brdp);

        return(0);
}

/*****************************************************************************/

/*
 *      Find all Stallion PCI boards that might be installed. Initialize each
 *      one as it is found.
 */


static inline int stl_findpcibrds()
{
        struct pci_dev  *dev = NULL;
        int             i, rc;

#if DEBUG
        printk("stl_findpcibrds()\n");
#endif

        if (! pci_present())
                return(0);

        for (i = 0; (i < stl_nrpcibrds); i++)
                while ((dev = pci_find_device(stl_pcibrds[i].vendid,
                    stl_pcibrds[i].devid, dev))) {

/*
 *                      Found a device on the PCI bus that has our vendor and
 *                      device ID. Need to check now that it is really us.
 */
                        if ((dev->class >> 8) == PCI_CLASS_STORAGE_IDE)
                                continue;

                        rc = stl_initpcibrd(stl_pcibrds[i].brdtype, dev);
                        if (rc)
                                return(rc);
                }

        return(0);
}

#endif

/*****************************************************************************/

/*
 *      Scan through all the boards in the configuration and see what we
 *      can find. Handle EIO and the ECH boards a little differently here
 *      since the initial search and setup is too different.
 */

static inline int stl_initbrds()
{
        stlbrd_t        *brdp;
        stlconf_t       *confp;
        int             i;

#if DEBUG
        printk("stl_initbrds()\n");
#endif

        if (stl_nrbrds > STL_MAXBRDS) {
                printk("STALLION: too many boards in configuration table, "
                        "truncating to %d\n", STL_MAXBRDS);
                stl_nrbrds = STL_MAXBRDS;
        }

/*
 *      Firstly scan the list of static boards configured. Allocate
 *      resources and initialize the boards as found.
 */
        for (i = 0; (i < stl_nrbrds); i++) {
                confp = &stl_brdconf[i];
#ifdef MODULE
                stl_parsebrd(confp, stl_brdsp[i]);
#endif
                if ((brdp = stl_allocbrd()) == (stlbrd_t *) NULL)
                        return(-ENOMEM);
                brdp->brdnr = i;
                brdp->brdtype = confp->brdtype;
                brdp->ioaddr1 = confp->ioaddr1;
                brdp->ioaddr2 = confp->ioaddr2;
                brdp->irq = confp->irq;
                brdp->irqtype = confp->irqtype;
                stl_brdinit(brdp);
        }

/*
 *      Find any dynamically supported boards. That is via module load
 *      line options or auto-detected on the PCI bus.
 */
#ifdef MODULE
        stl_argbrds();
#endif
#ifdef CONFIG_PCI
        stl_findpcibrds();
#endif

        return(0);
}

/*****************************************************************************/

/*
 *      Return the board stats structure to user app.
 */

static int stl_getbrdstats(combrd_t *bp)
{
        stlbrd_t        *brdp;
        stlpanel_t      *panelp;
        int             i;

        if (copy_from_user(&stl_brdstats, bp, sizeof(combrd_t)))
                return -EFAULT;
        if (stl_brdstats.brd >= STL_MAXBRDS)
                return(-ENODEV);
        brdp = stl_brds[stl_brdstats.brd];
        if (brdp == (stlbrd_t *) NULL)
                return(-ENODEV);

        memset(&stl_brdstats, 0, sizeof(combrd_t));
        stl_brdstats.brd = brdp->brdnr;
        stl_brdstats.type = brdp->brdtype;
        stl_brdstats.hwid = brdp->hwid;
        stl_brdstats.state = brdp->state;
        stl_brdstats.ioaddr = brdp->ioaddr1;
        stl_brdstats.ioaddr2 = brdp->ioaddr2;
        stl_brdstats.irq = brdp->irq;
        stl_brdstats.nrpanels = brdp->nrpanels;
        stl_brdstats.nrports = brdp->nrports;
        for (i = 0; (i < brdp->nrpanels); i++) {
                panelp = brdp->panels[i];
                stl_brdstats.panels[i].panel = i;
                stl_brdstats.panels[i].hwid = panelp->hwid;
                stl_brdstats.panels[i].nrports = panelp->nrports;
        }

        return copy_to_user(bp, &stl_brdstats, sizeof(combrd_t)) ? -EFAULT : 0;
}

/*****************************************************************************/

/*
 *      Resolve the referenced port number into a port struct pointer.
 */

static stlport_t *stl_getport(int brdnr, int panelnr, int portnr)
{
        stlbrd_t        *brdp;
        stlpanel_t      *panelp;

        if ((brdnr < 0) || (brdnr >= STL_MAXBRDS))
                return((stlport_t *) NULL);
        brdp = stl_brds[brdnr];
        if (brdp == (stlbrd_t *) NULL)
                return((stlport_t *) NULL);
        if ((panelnr < 0) || (panelnr >= brdp->nrpanels))
                return((stlport_t *) NULL);
        panelp = brdp->panels[panelnr];
        if (panelp == (stlpanel_t *) NULL)
                return((stlport_t *) NULL);
        if ((portnr < 0) || (portnr >= panelp->nrports))
                return((stlport_t *) NULL);
        return(panelp->ports[portnr]);
}

/*****************************************************************************/

/*
 *      Return the port stats structure to user app. A NULL port struct
 *      pointer passed in means that we need to find out from the app
 *      what port to get stats for (used through board control device).
 */

static int stl_getportstats(stlport_t *portp, comstats_t *cp)
{
        unsigned char   *head, *tail;
        unsigned long   flags;

        if (portp == (stlport_t *) NULL) {
                if (copy_from_user(&stl_comstats, cp, sizeof(comstats_t)))
                        return -EFAULT;
                portp = stl_getport(stl_comstats.brd, stl_comstats.panel,
                        stl_comstats.port);
                if (portp == (stlport_t *) NULL)
                        return(-ENODEV);
        }

        portp->stats.state = portp->istate;
        portp->stats.flags = portp->flags;
        portp->stats.hwid = portp->hwid;

        portp->stats.ttystate = 0;
        portp->stats.cflags = 0;
        portp->stats.iflags = 0;
        portp->stats.oflags = 0;
        portp->stats.lflags = 0;
        portp->stats.rxbuffered = 0;

        save_flags(flags);
        cli();
        if (portp->tty != (struct tty_struct *) NULL) {
                if (portp->tty->driver_data == portp) {
                        portp->stats.ttystate = portp->tty->flags;
                        portp->stats.rxbuffered = portp->tty->flip.count;
                        if (portp->tty->termios != (struct termios *) NULL) {
                                portp->stats.cflags = portp->tty->termios->c_cflag;
                                portp->stats.iflags = portp->tty->termios->c_iflag;
                                portp->stats.oflags = portp->tty->termios->c_oflag;
                                portp->stats.lflags = portp->tty->termios->c_lflag;
                        }
                }
        }
        restore_flags(flags);

        head = portp->tx.head;
        tail = portp->tx.tail;
        portp->stats.txbuffered = ((head >= tail) ? (head - tail) :
                (STL_TXBUFSIZE - (tail - head)));