sch311x_wdt.c

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/*
 *  sch311x_wdt.c - Driver for the SCH311x Super-I/O chips
 *          integrated watchdog.
 *
 *  (c) Copyright 2008 Wim Van Sebroeck <[email protected]>.
 *
 *  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.
 *
 *  Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
 *  provide warranty for any of this software. This material is
 *  provided "AS-IS" and at no charge.
 */

/*
 *  Includes, defines, variables, module parameters, ...
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

/* Includes */
#include <linux/module.h>       /* For module specific items */
#include <linux/moduleparam.h>      /* For new moduleparam's */
#include <linux/types.h>        /* For standard types (like size_t) */
#include <linux/errno.h>        /* For the -ENODEV/... values */
#include <linux/kernel.h>       /* For printk/... */
#include <linux/miscdevice.h>       /* For MODULE_ALIAS_MISCDEV
                            (WATCHDOG_MINOR) */
#include <linux/watchdog.h>     /* For the watchdog specific items */
#include <linux/init.h>         /* For __init/__exit/... */
#include <linux/fs.h>           /* For file operations */
#include <linux/platform_device.h>  /* For platform_driver framework */
#include <linux/ioport.h>       /* For io-port access */
#include <linux/spinlock.h>     /* For spin_lock/spin_unlock/... */
#include <linux/uaccess.h>      /* For copy_to_user/put_user/... */
#include <linux/io.h>           /* For inb/outb/... */

/* Module and version information */
#define DRV_NAME    "sch311x_wdt"

/* Runtime registers */
#define GP60            0x47
#define WDT_TIME_OUT        0x65
#define WDT_VAL         0x66
#define WDT_CFG         0x67
#define WDT_CTRL        0x68

/* internal variables */
static unsigned long sch311x_wdt_is_open;
static char sch311x_wdt_expect_close;
static struct platform_device *sch311x_wdt_pdev;

static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e, 0x00 };

static struct { /* The devices private data */
    /* the Runtime Register base address */
    unsigned short runtime_reg;
    /* The card's boot status */
    int boot_status;
    /* the lock for io operations */
    spinlock_t io_lock;
} sch311x_wdt_data;

/* Module load parameters */
static unsigned short force_id;
module_param(force_id, ushort, 0);
MODULE_PARM_DESC(force_id, "Override the detected device ID");

#define WATCHDOG_TIMEOUT 60     /* 60 sec default timeout */
static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
    "Watchdog timeout in seconds. 1<= timeout <=15300, default="
        __MODULE_STRING(WATCHDOG_TIMEOUT) ".");

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
    "Watchdog cannot be stopped once started (default="
        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

/*
 *  Super-IO functions
 */

static inline void sch311x_sio_enter(int sio_config_port)
{
    outb(0x55, sio_config_port);
}

static inline void sch311x_sio_exit(int sio_config_port)
{
    outb(0xaa, sio_config_port);
}

static inline int sch311x_sio_inb(int sio_config_port, int reg)
{
    outb(reg, sio_config_port);
    return inb(sio_config_port + 1);
}

static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
{
    outb(reg, sio_config_port);
    outb(val, sio_config_port + 1);
}

/*
 *  Watchdog Operations
 */

static void sch311x_wdt_set_timeout(int t)
{
    unsigned char timeout_unit = 0x80;

    /* When new timeout is bigger then 255 seconds, we will use minutes */
    if (t > 255) {
        timeout_unit = 0;
        t /= 60;
    }

    /* -- Watchdog Timeout --
     * Bit 0-6 (Reserved)
     * Bit 7   WDT Time-out Value Units Select
     *         (0 = Minutes, 1 = Seconds)
     */
    outb(timeout_unit, sch311x_wdt_data.runtime_reg + WDT_TIME_OUT);

    /* -- Watchdog Timer Time-out Value --
     * Bit 0-7 Binary coded units (0=Disabled, 1..255)
     */
    outb(t, sch311x_wdt_data.runtime_reg + WDT_VAL);
}

static void sch311x_wdt_start(void)
{
    unsigned char t;

    spin_lock(&sch311x_wdt_data.io_lock);

    /* set watchdog's timeout */
    sch311x_wdt_set_timeout(timeout);
    /* enable the watchdog */
    /* -- General Purpose I/O Bit 6.0 --
     * Bit 0,   In/Out: 0 = Output, 1 = Input
     * Bit 1,   Polarity: 0 = No Invert, 1 = Invert
     * Bit 2-3, Function select: 00 = GPI/O, 01 = LED1, 11 = WDT,
     *                           10 = Either Edge Triggered Intr.4
     * Bit 4-6  (Reserved)
     * Bit 7,   Output Type: 0 = Push Pull Bit, 1 = Open Drain
     */
    t = inb(sch311x_wdt_data.runtime_reg + GP60);
    outb((t & ~0x0d) | 0x0c, sch311x_wdt_data.runtime_reg + GP60);

    spin_unlock(&sch311x_wdt_data.io_lock);

}

static void sch311x_wdt_stop(void)
{
    unsigned char t;

    spin_lock(&sch311x_wdt_data.io_lock);

    /* stop the watchdog */
    t = inb(sch311x_wdt_data.runtime_reg + GP60);
    outb((t & ~0x0d) | 0x01, sch311x_wdt_data.runtime_reg + GP60);
    /* disable timeout by setting it to 0 */
    sch311x_wdt_set_timeout(0);

    spin_unlock(&sch311x_wdt_data.io_lock);
}

static void sch311x_wdt_keepalive(void)
{
    spin_lock(&sch311x_wdt_data.io_lock);
    sch311x_wdt_set_timeout(timeout);
    spin_unlock(&sch311x_wdt_data.io_lock);
}

static int sch311x_wdt_set_heartbeat(int t)
{
    if (t < 1 || t > (255*60))
        return -EINVAL;

    /* When new timeout is bigger then 255 seconds,
     * we will round up to minutes (with a max of 255) */
    if (t > 255)
        t = (((t - 1) / 60) + 1) * 60;

    timeout = t;
    return 0;
}

static void sch311x_wdt_get_status(int *status)
{
    unsigned char new_status;

    *status = 0;

    spin_lock(&sch311x_wdt_data.io_lock);

    /* -- Watchdog timer control --
     * Bit 0   Status Bit: 0 = Timer counting, 1 = Timeout occurred
     * Bit 1   Reserved
     * Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)
     * Bit 3   P20 Force Timeout enabled:
     *          0 = P20 activity does not generate the WD timeout event
     *          1 = P20 Allows rising edge of P20, from the keyboard
     *              controller, to force the WD timeout event.
     * Bit 4-7 Reserved
     */
    new_status = inb(sch311x_wdt_data.runtime_reg + WDT_CTRL);
    if (new_status & 0x01)
        *status |= WDIOF_CARDRESET;

    spin_unlock(&sch311x_wdt_data.io_lock);
}

/*
 *  /dev/watchdog handling
 */

static ssize_t sch311x_wdt_write(struct file *file, const char __user *buf,
                        size_t count, loff_t *ppos)
{
    if (count) {
        if (!nowayout) {
            size_t i;

            sch311x_wdt_expect_close = 0;

            for (i = 0; i != count; i++) {
                char c;
                if (get_user(c, buf + i))
                    return -EFAULT;
                if (c == 'V')
                    sch311x_wdt_expect_close = 42;
            }
        }
        sch311x_wdt_keepalive();
    }
    return count;
}

static long sch311x_wdt_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
    int status;
    int new_timeout;
    void __user *argp = (void __user *)arg;
    int __user *p = argp;
    static const struct watchdog_info ident = {
        .options        = WDIOF_KEEPALIVEPING |
                      WDIOF_SETTIMEOUT |
                      WDIOF_MAGICCLOSE,
        .firmware_version   = 1,
        .identity       = DRV_NAME,
    };

    switch (cmd) {
    case WDIOC_GETSUPPORT:
        if (copy_to_user(argp, &ident, sizeof(ident)))
            return -EFAULT;
        break;

    case WDIOC_GETSTATUS:
    {
        sch311x_wdt_get_status(&status);
        return put_user(status, p);
    }
    case WDIOC_GETBOOTSTATUS:
        return put_user(sch311x_wdt_data.boot_status, p);

    case WDIOC_SETOPTIONS:
    {
        int options, retval = -EINVAL;

        if (get_user(options, p))
            return -EFAULT;
        if (options & WDIOS_DISABLECARD) {
            sch311x_wdt_stop();
            retval = 0;
        }
        if (options & WDIOS_ENABLECARD) {
            sch311x_wdt_start();
            retval = 0;
        }
        return retval;
    }
    case WDIOC_KEEPALIVE:
        sch311x_wdt_keepalive();
        break;

    case WDIOC_SETTIMEOUT:
        if (get_user(new_timeout, p))
            return -EFAULT;
        if (sch311x_wdt_set_heartbeat(new_timeout))
            return -EINVAL;
        sch311x_wdt_keepalive();
        /* Fall */
    case WDIOC_GETTIMEOUT:
        return put_user(timeout, p);
    default:
        return -ENOTTY;
    }
    return 0;
}

static int sch311x_wdt_open(struct inode *inode, struct file *file)
{
    if (test_and_set_bit(0, &sch311x_wdt_is_open))
        return -EBUSY;
    /*
     *  Activate
     */
    sch311x_wdt_start();
    return nonseekable_open(inode, file);
}

static int sch311x_wdt_close(struct inode *inode, struct file *file)
{
    if (sch311x_wdt_expect_close == 42) {
        sch311x_wdt_stop();
    } else {
        pr_crit("Unexpected close, not stopping watchdog!\n");
        sch311x_wdt_keepalive();
    }
    clear_bit(0, &sch311x_wdt_is_open);
    sch311x_wdt_expect_close = 0;
    return 0;
}

/*
 *  Kernel Interfaces
 */

static const struct file_operations sch311x_wdt_fops = {
    .owner      = THIS_MODULE,
    .llseek     = no_llseek,
    .write      = sch311x_wdt_write,
    .unlocked_ioctl = sch311x_wdt_ioctl,
    .open       = sch311x_wdt_open,
    .release    = sch311x_wdt_close,
};

static struct miscdevice sch311x_wdt_miscdev = {
    .minor  = WATCHDOG_MINOR,
    .name   = "watchdog",
    .fops   = &sch311x_wdt_fops,
};

/*
 *  Init & exit routines
 */

static int __devinit sch311x_wdt_probe(struct platform_device *pdev)
{
    struct device *dev = &pdev->dev;
    int err;

    spin_lock_init(&sch311x_wdt_data.io_lock);

    if (!request_region(sch311x_wdt_data.runtime_reg + GP60, 1, DRV_NAME)) {
        dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
            sch311x_wdt_data.runtime_reg + GP60,
            sch311x_wdt_data.runtime_reg + GP60);
        err = -EBUSY;
        goto exit;
    }

    if (!request_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4,
                                DRV_NAME)) {
        dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
            sch311x_wdt_data.runtime_reg + WDT_TIME_OUT,
            sch311x_wdt_data.runtime_reg + WDT_CTRL);
        err = -EBUSY;
        goto exit_release_region;
    }

    /* Make sure that the watchdog is not running */
    sch311x_wdt_stop();

    /* Disable keyboard and mouse interaction and interrupt */
    /* -- Watchdog timer configuration --
     * Bit 0   Reserved
     * Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
     * Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
     * Bit 3   Reserved
     * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
     *            0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
     */
    outb(0, sch311x_wdt_data.runtime_reg + WDT_CFG);

    /* Check that the heartbeat value is within it's range ;
     * if not reset to the default */
    if (sch311x_wdt_set_heartbeat(timeout)) {
        sch311x_wdt_set_heartbeat(WATCHDOG_TIMEOUT);
        dev_info(dev, "timeout value must be 1<=x<=15300, using %d\n",
            timeout);
    }

    /* Get status at boot */
    sch311x_wdt_get_status(&sch311x_wdt_data.boot_status);

    sch311x_wdt_miscdev.parent = dev;

    err = misc_register(&sch311x_wdt_miscdev);
    if (err != 0) {
        dev_err(dev, "cannot register miscdev on minor=%d (err=%d)\n",
                            WATCHDOG_MINOR, err);
        goto exit_release_region2;
    }

    dev_info(dev,
        "SMSC SCH311x WDT initialized. timeout=%d sec (nowayout=%d)\n",
        timeout, nowayout);

    return 0;

exit_release_region2:
    release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
exit_release_region:
    release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
    sch311x_wdt_data.runtime_reg = 0;
exit:
    return err;
}

static int __devexit sch311x_wdt_remove(struct platform_device *pdev)
{
    /* Stop the timer before we leave */
    if (!nowayout)
        sch311x_wdt_stop();

    /* Deregister */
    misc_deregister(&sch311x_wdt_miscdev);
    release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
    release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
    sch311x_wdt_data.runtime_reg = 0;
    return 0;
}

static void sch311x_wdt_shutdown(struct platform_device *dev)
{
    /* Turn the WDT off if we have a soft shutdown */
    sch311x_wdt_stop();
}

static struct platform_driver sch311x_wdt_driver = {
    .probe      = sch311x_wdt_probe,
    .remove     = __devexit_p(sch311x_wdt_remove),
    .shutdown   = sch311x_wdt_shutdown,
    .driver     = {
        .owner = THIS_MODULE,
        .name = DRV_NAME,
    },
};

static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
{
    int err = 0, reg;
    unsigned short base_addr;
    unsigned char dev_id;

    sch311x_sio_enter(sio_config_port);

    /* Check device ID. We currently know about:
     * SCH3112 (0x7c), SCH3114 (0x7d), and SCH3116 (0x7f). */
    reg = force_id ? force_id : sch311x_sio_inb(sio_config_port, 0x20);
    if (!(reg == 0x7c || reg == 0x7d || reg == 0x7f)) {
        err = -ENODEV;
        goto exit;
    }
    dev_id = reg == 0x7c ? 2 : reg == 0x7d ? 4 : 6;

    /* Select logical device A (runtime registers) */
    sch311x_sio_outb(sio_config_port, 0x07, 0x0a);

    /* Check if Logical Device Register is currently active */
    if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
        pr_info("Seems that LDN 0x0a is not active...\n");

    /* Get the base address of the runtime registers */
    base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
               sch311x_sio_inb(sio_config_port, 0x61);
    if (!base_addr) {
        pr_err("Base address not set\n");
        err = -ENODEV;
        goto exit;
    }
    *addr = base_addr;

    pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);

exit:
    sch311x_sio_exit(sio_config_port);
    return err;
}

static int __init sch311x_wdt_init(void)
{
    int err, i, found = 0;
    unsigned short addr = 0;

    for (i = 0; !found && sch311x_ioports[i]; i++)
        if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
            found++;

    if (!found)
        return -ENODEV;

    sch311x_wdt_data.runtime_reg = addr;

    err = platform_driver_register(&sch311x_wdt_driver);
    if (err)
        return err;

    sch311x_wdt_pdev = platform_device_register_simple(DRV_NAME, addr,
                                NULL, 0);

    if (IS_ERR(sch311x_wdt_pdev)) {
        err = PTR_ERR(sch311x_wdt_pdev);
        goto unreg_platform_driver;
    }

    return 0;

unreg_platform_driver:
    platform_driver_unregister(&sch311x_wdt_driver);
    return err;
}

static void __exit sch311x_wdt_exit(void)
{
    platform_device_unregister(sch311x_wdt_pdev);
    platform_driver_unregister(&sch311x_wdt_driver);
}

module_init(sch311x_wdt_init);
module_exit(sch311x_wdt_exit);

MODULE_AUTHOR("Wim Van Sebroeck <[email protected]>");
MODULE_DESCRIPTION("SMSC SCH311x WatchDog Timer Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);