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/*

 * PC Watchdog Driver

 * by Ken Hollis (khollis@bitgate.com)

 *

 * Permission granted from Simon Machell (73244.1270@compuserve.com)

 * Written for the Linux Kernel, and GPLed by Ken Hollis

 *

 * 960107       Added request_region routines, modulized the whole thing.

 * 960108       Fixed end-of-file pointer (Thanks to Dan Hollis), added

 *              WD_TIMEOUT define.

 * 960216       Added eof marker on the file, and changed verbose messages.

 * 960716       Made functional and cosmetic changes to the source for

 *              inclusion in Linux 2.0.x kernels, thanks to Alan Cox.

 * 960717       Removed read/seek routines, replaced with ioctl.  Also, added

 *              check_region command due to Alan's suggestion.

 * 960821       Made changes to compile in newer 2.0.x kernels.  Added

 *              "cold reboot sense" entry.

 * 970819       Fixed use of is_open flag so pcwd_write does not always return

 *              -EIO; this prevented tickling. Enabled board on open and

 *              disabled on close.

 */

#include <linux/module.h>

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/sched.h>

#include <linux/tty.h>

#include <linux/timer.h>

#include <linux/kernel.h>

#include <linux/wait.h>

#include <linux/string.h>

#include <linux/malloc.h>

#include <linux/ioport.h>

#include <linux/delay.h>

#include <linux/miscdevice.h>

#include <linux/fs.h>

#include <linux/mm.h>

#include <linux/pcwd.h>

#include <asm/io.h>

#define WD_VER                  "0.50 (08/21/96)"

#define WD_MINOR                130     /* Minor device number */

#define WD_TIMEOUT              3       /* 1 1/2 seconds for a timeout */

#define WD_TIMERRESET_PORT1     0x270   /* Reset port - first choice */

#define WD_TIMERRESET_PORT2     0x370   /* Reset port - second choice */

#define WD_CTLSTAT_PORT1        0x271   /* Control port - first choice */

#define WD_CTLSTAT_PORT2        0x371   /* Control port - second choice */

#define WD_CTLSTAT2_PORT1       0x272   /* Control port#2 - first choice */

#define WD_CTLSTAT2_PORT2       0x372   /* Control port#2 - second choice */

#define WD_DISABLE_PORT1        0x273   /* Disable port - first choice  */

#define WD_DISABLE_PORT2        0x373   /* Disable port - second choice  */

#define WD_PORT_EXTENT          4       /* Takes up four addresses */

#define WD_WDRST                0x01    /* Previously reset state */

#define WD_T110                 0x02    /* Temperature overheat sense */

#define WD_HRTBT                0x04    /* Heartbeat sense */

#define WD_RLY2                 0x08    /* External relay triggered */

#define WD_SRLY2                0x80    /* Software external relay triggered */

static int current_ctlport, current_readport;

static int current_ctlport2, current_disport;

static int is_open, is_eof;

int pcwd_checkcard(void)

{

        int card_dat, prev_card_dat, found = 0, count = 0, done = 0;

        /* As suggested by Alan Cox */

        if (check_region(current_ctlport, WD_PORT_EXTENT)) {

                printk("pcwd: Port 0x%x unavailable.\n", current_ctlport);

                return 0;

        }

        card_dat = 0x00;

        prev_card_dat = 0x00;

        prev_card_dat = inb(current_readport);

        while(count < WD_TIMEOUT) {

#ifdef  DEBUG

                printk("pcwd: Run #%d on port 0x%03x\n", count, current_readport);

#endif

        /* Read the raw card data from the port, and strip off the

           first 4 bits */

                card_dat = inb_p(current_readport);

                card_dat &= 0x000F;

        /* Sleep 1/2 second (or 500000 microseconds :) */

                udelay(500000L);

                done = 0;

        /* 0x0F usually means that no card data is present, or the card

           is not installed on this port.  If 0x0F is present here, it's

           normally safe to assume there's no card at that base address. */

                if (card_dat == 0x0F) {

                        count++;

                        done = 1;

#ifdef  DEBUG

                        printk("pcwd: I show nothing on this port.\n");

#endif

                }

        /* If there's a heart beat in both instances, then this means we

           found our card.  This also means that either the card was

           previously reset, or the computer was power-cycled. */

                if ((card_dat & WD_HRTBT) && (prev_card_dat & WD_HRTBT) &&

                        (!done)) {

                        found = 1;

                        done = 1;

#ifdef  DEBUG

                        printk("pcwd: I show alternate heart beats.  Card detected.\n");

#endif

                        break;

                }

        /* If the card data is exactly the same as the previous card data,

           it's safe to assume that we should check again.  The manual says

           that the heart beat will change every second (or the bit will

           toggle), and this can be used to see if the card is there.  If

           the card was powered up with a cold boot, then the card will

           not start blinking until 2.5 minutes after a reboot, so this

           bit will stay at 1. */

                if ((card_dat == prev_card_dat) && (!done)) {

                        count++;

#ifdef  DEBUG

                        printk("pcwd: The card data is exactly the same (possibility).\n");

#endif

                        done = 1;

                }

        /* If the card data is toggling any bits, this means that the heart

           beat was detected, or something else about the card is set. */

                if ((card_dat != prev_card_dat) && (!done)) {

                        done = 1;

                        found = 1;

#ifdef  DEBUG

                        printk("pcwd: I show alternate heart beats.  Card detected.\n");

#endif

                        break;

                }

        /* Otherwise something else strange happened. */

                if (!done)

                        count++;

        }

        return((found) ? 1 : 0);

}

void pcwd_showprevstate(void)

{

        int card_status = 0x0000;

        card_status = inb(current_readport);

        if (card_status & WD_WDRST)

                printk("pcwd: Previous reboot was caused by the card.\n");

        if (card_status & WD_T110)

                printk("pcwd: CPU overheat sense.\n");

        if ((!(card_status & WD_WDRST)) &&

            (!(card_status & WD_T110)))

                printk("pcwd: Cold boot sense.\n");

}

static int pcwd_return_data(void)

{

        return(inb(current_readport));

}

static int pcwd_write(struct inode *inode, struct file *file, const char *data,

        int len)

{

        int wdrst_stat;

        if (!is_open)

                return -EIO;

#ifdef  DEBUG

        printk("pcwd: write request\n");

#endif

        wdrst_stat = inb_p(current_readport);

        wdrst_stat &= 0x0F;

        wdrst_stat |= WD_WDRST;

        outb_p(wdrst_stat, current_ctlport);

        return(len);

}

static int pcwd_ioctl(struct inode *inode, struct file *file,

        unsigned int cmd, unsigned long arg)

{

        int i, cdat, rv;

        switch(cmd) {

        default:

                return -ENOIOCTLCMD;

        case PCWD_GETSTAT:

                i = verify_area(VERIFY_WRITE, (void*) arg, sizeof(int));

                if (i)

                        return i;

                else {

                        cdat = pcwd_return_data();

                        rv = 0;

                        if (cdat & WD_WDRST)

                                rv |= 0x01;

                        if (cdat & WD_T110)

                                rv |= 0x02;

                        put_user(rv, (int *) arg);

                        return 0;

                }

                break;

        case PCWD_PING:

                pcwd_write(NULL, NULL, NULL, 1);        /* Is this legal? */

                break;

        }

        return 0;

}

static int pcwd_open(struct inode *ino, struct file *filep)

{

#ifdef  DEBUG

        int before, after;

        before = inb_p (current_ctlport2);

#endif

        if (is_open)

                return -EIO;

        /*  Enable the port  */

        outb_p (0, current_disport);

#ifdef  DEBUG

        after = inb_p (current_ctlport2);

        printk ("pcwd: open: control status #2 (b,a): %x, %x\n", before,after);

#endif

        MOD_INC_USE_COUNT;

        is_open = 1;

        is_eof = 0;

        return(0);

}

static void pcwd_close(struct inode *ino, struct file *filep)

{

#ifdef  DEBUG

        printk("pcwd: close request\n");

#endif

        is_open = 0;

        /*  Disable the board  */

        outb_p (0xa5, current_disport);

        outb_p (0xa5, current_disport);

        MOD_DEC_USE_COUNT;

}

static struct file_operations pcwd_fops = {

        NULL,           /* Seek */

        NULL,           /* Read */

        pcwd_write,     /* Write */

        NULL,           /* Readdir */

        NULL,           /* Select */

        pcwd_ioctl,     /* IOctl */

        NULL,           /* MMAP */

        pcwd_open,      /* Open */

        pcwd_close      /* Close */

};

static struct miscdevice pcwd_miscdev = {

        WD_MINOR,

        "pcwatchdog",

        &pcwd_fops

};

#ifdef  MODULE

int init_module(void)

#else

int pcwatchdog_init(void)

#endif

{

#ifdef  DEBUG

        printk("pcwd: Success.\n");

#endif

        printk("pcwd: v%s Ken Hollis (khollis@bitgate.com)\n", WD_VER);

#ifdef  DEBUG

        printk("pcwd: About to perform card autosense loop.\n");

#endif

        is_eof = 0;

        is_open = 0;

        current_ctlport = WD_TIMERRESET_PORT1;

        current_readport = WD_CTLSTAT_PORT1;

        current_ctlport2 = WD_CTLSTAT2_PORT1;

        current_disport = WD_DISABLE_PORT1;

        if (!pcwd_checkcard()) {

#ifdef  DEBUG

                printk("pcwd: Trying port 0x370.\n");

#endif

                current_ctlport = WD_TIMERRESET_PORT2;

                current_readport = WD_CTLSTAT_PORT2;

                current_ctlport2 = WD_CTLSTAT2_PORT2;

                current_disport = WD_DISABLE_PORT2;

                if (!pcwd_checkcard()) {

                        printk("pcwd: No card detected, or wrong port assigned.\n");

                        return(-EIO);

                } else

                        printk("pcwd: Watchdog Rev.A detected at port 0x370\n");

        } else

                printk("pcwd: Watchdog Rev.A detected at port 0x270\n");

        pcwd_showprevstate();

#ifdef  DEBUG

        printk("pcwd: Requesting region entry\n");

#endif

        request_region(current_ctlport, WD_PORT_EXTENT, "PCWD Rev.A (Berkshire)");

#ifdef  DEBUG

        printk("pcwd: character device creation.\n");

#endif

        misc_register(&pcwd_miscdev);

        return 0;

}

#ifdef  MODULE

void cleanup_module(void)

{

        /*  Disable the board  */

        outb_p (0xa5, current_disport);

        outb_p (0xa5, current_disport);

        misc_deregister(&pcwd_miscdev);

        release_region(current_ctlport, WD_PORT_EXTENT);

#ifdef  DEBUG

        printk("pcwd: Cleanup successful.\n");

#endif

}

#endif

/*

** TODO:

**

**      Both Revisions:

**      o) Support for revision B of the Watchdog Card

**      o) Implement the rest of the IOCTLs as discussed with Alan Cox

**      o) Implement only card heartbeat reset via IOCTL, not via write

**      o) Faster card detection routines

**      o) /proc device creation

**

**      Revision B functions:

**      o) /dev/temp device creation for temperature device (possibly use

**         the one from the WDT drivers?)

**      o) Direct Motorola controller chip access via read/write routines

**      o) Autoprobe IO Ports for autodetection (possibly by chip detect?)

*/