drivers/watchdog/wdt977.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  Wdt977  0.04:   A Watchdog Device for Netwinder W83977AF chip
0004  *
0005  *  (c) Copyright 1998 Rebel.com (Woody Suwalski <woody@netwinder.org>)
0006  *
0007  *          -----------------------
0008  *
0009  *          -----------------------
0010  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
0011  *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
0012  *  19-Dec-2001 Woody Suwalski: Netwinder fixes, ioctl interface
0013  *  06-Jan-2002 Woody Suwalski: For compatibility, convert all timeouts
0014  *                  from minutes to seconds.
0015  *      07-Jul-2003 Daniele Bellucci: Audit return code of misc_register in
0016  *                                    nwwatchdog_init.
0017  *      25-Oct-2005 Woody Suwalski: Convert addresses to #defs, add spinlocks
0018  *                  remove limitiation to be used on
0019  *                  Netwinders only
0020  */
0021
0022 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0023
0024 #include <linux/module.h>
0025 #include <linux/moduleparam.h>
0026 #include <linux/types.h>
0027 #include <linux/kernel.h>
0028 #include <linux/fs.h>
0029 #include <linux/miscdevice.h>
0030 #include <linux/init.h>
0031 #include <linux/ioport.h>
0032 #include <linux/watchdog.h>
0033 #include <linux/notifier.h>
0034 #include <linux/reboot.h>
0035 #include <linux/io.h>
0036 #include <linux/uaccess.h>
0037
0038 #include <asm/mach-types.h>
0039
0040 #define WATCHDOG_VERSION  "0.04"
0041 #define WATCHDOG_NAME     "Wdt977"
0042
0043 #define IO_INDEX_PORT   0x370       /* on some systems it can be 0x3F0 */
0044 #define IO_DATA_PORT    (IO_INDEX_PORT + 1)
0045
0046 #define UNLOCK_DATA 0x87
0047 #define LOCK_DATA   0xAA
0048 #define DEVICE_REGISTER 0x07
0049
0050
0051 #define DEFAULT_TIMEOUT 60          /* default timeout in seconds */
0052
0053 static  int timeout = DEFAULT_TIMEOUT;
0054 static  int timeoutM;               /* timeout in minutes */
0055 static  unsigned long timer_alive;
0056 static  int testmode;
0057 static  char expect_close;
0058 static  DEFINE_SPINLOCK(spinlock);
0059
0060 module_param(timeout, int, 0);
0061 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (60..15300, default="
0062                 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
0063 module_param(testmode, int, 0);
0064 MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
0065
0066 static bool nowayout = WATCHDOG_NOWAYOUT;
0067 module_param(nowayout, bool, 0);
0068 MODULE_PARM_DESC(nowayout,
0069         "Watchdog cannot be stopped once started (default="
0070                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
0071
0072 /*
0073  * Start the watchdog
0074  */
0075
0076 static int wdt977_start(void)
0077 {
0078     unsigned long flags;
0079
0080     spin_lock_irqsave(&spinlock, flags);
0081
0082     /* unlock the SuperIO chip */
0083     outb_p(UNLOCK_DATA, IO_INDEX_PORT);
0084     outb_p(UNLOCK_DATA, IO_INDEX_PORT);
0085
0086     /* select device Aux2 (device=8) and set watchdog regs F2, F3 and F4
0087      * F2 has the timeout in minutes
0088      * F3 could be set to the POWER LED blink (with GP17 set to PowerLed)
0089      *   at timeout, and to reset timer on kbd/mouse activity (not impl.)
0090      * F4 is used to just clear the TIMEOUT'ed state (bit 0)
0091      */
0092     outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
0093     outb_p(0x08, IO_DATA_PORT);
0094     outb_p(0xF2, IO_INDEX_PORT);
0095     outb_p(timeoutM, IO_DATA_PORT);
0096     outb_p(0xF3, IO_INDEX_PORT);
0097     outb_p(0x00, IO_DATA_PORT); /* another setting is 0E for
0098                        kbd/mouse/LED */
0099     outb_p(0xF4, IO_INDEX_PORT);
0100     outb_p(0x00, IO_DATA_PORT);
0101
0102     /* At last select device Aux1 (dev=7) and set GP16 as a
0103      * watchdog output. In test mode watch the bit 1 on F4 to
0104      * indicate "triggered"
0105      */
0106     if (!testmode) {
0107         outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
0108         outb_p(0x07, IO_DATA_PORT);
0109         outb_p(0xE6, IO_INDEX_PORT);
0110         outb_p(0x08, IO_DATA_PORT);
0111     }
0112
0113     /* lock the SuperIO chip */
0114     outb_p(LOCK_DATA, IO_INDEX_PORT);
0115
0116     spin_unlock_irqrestore(&spinlock, flags);
0117     pr_info("activated\n");
0118
0119     return 0;
0120 }
0121
0122 /*
0123  * Stop the watchdog
0124  */
0125
0126 static int wdt977_stop(void)
0127 {
0128     unsigned long flags;
0129     spin_lock_irqsave(&spinlock, flags);
0130
0131     /* unlock the SuperIO chip */
0132     outb_p(UNLOCK_DATA, IO_INDEX_PORT);
0133     outb_p(UNLOCK_DATA, IO_INDEX_PORT);
0134
0135     /* select device Aux2 (device=8) and set watchdog regs F2,F3 and F4
0136     * F3 is reset to its default state
0137     * F4 can clear the TIMEOUT'ed state (bit 0) - back to default
0138     * We can not use GP17 as a PowerLed, as we use its usage as a RedLed
0139     */
0140     outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
0141     outb_p(0x08, IO_DATA_PORT);
0142     outb_p(0xF2, IO_INDEX_PORT);
0143     outb_p(0xFF, IO_DATA_PORT);
0144     outb_p(0xF3, IO_INDEX_PORT);
0145     outb_p(0x00, IO_DATA_PORT);
0146     outb_p(0xF4, IO_INDEX_PORT);
0147     outb_p(0x00, IO_DATA_PORT);
0148     outb_p(0xF2, IO_INDEX_PORT);
0149     outb_p(0x00, IO_DATA_PORT);
0150
0151     /* at last select device Aux1 (dev=7) and set
0152        GP16 as a watchdog output */
0153     outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
0154     outb_p(0x07, IO_DATA_PORT);
0155     outb_p(0xE6, IO_INDEX_PORT);
0156     outb_p(0x08, IO_DATA_PORT);
0157
0158     /* lock the SuperIO chip */
0159     outb_p(LOCK_DATA, IO_INDEX_PORT);
0160
0161     spin_unlock_irqrestore(&spinlock, flags);
0162     pr_info("shutdown\n");
0163
0164     return 0;
0165 }
0166
0167 /*
0168  * Send a keepalive ping to the watchdog
0169  * This is done by simply re-writing the timeout to reg. 0xF2
0170  */
0171
0172 static int wdt977_keepalive(void)
0173 {
0174     unsigned long flags;
0175     spin_lock_irqsave(&spinlock, flags);
0176
0177     /* unlock the SuperIO chip */
0178     outb_p(UNLOCK_DATA, IO_INDEX_PORT);
0179     outb_p(UNLOCK_DATA, IO_INDEX_PORT);
0180
0181     /* select device Aux2 (device=8) and kicks watchdog reg F2 */
0182     /* F2 has the timeout in minutes */
0183     outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
0184     outb_p(0x08, IO_DATA_PORT);
0185     outb_p(0xF2, IO_INDEX_PORT);
0186     outb_p(timeoutM, IO_DATA_PORT);
0187
0188     /* lock the SuperIO chip */
0189     outb_p(LOCK_DATA, IO_INDEX_PORT);
0190     spin_unlock_irqrestore(&spinlock, flags);
0191
0192     return 0;
0193 }
0194
0195 /*
0196  * Set the watchdog timeout value
0197  */
0198
0199 static int wdt977_set_timeout(int t)
0200 {
0201     int tmrval;
0202
0203     /* convert seconds to minutes, rounding up */
0204     tmrval = (t + 59) / 60;
0205
0206     if (machine_is_netwinder()) {
0207         /* we have a hw bug somewhere, so each 977 minute is actually
0208          * only 30sec. This limits the max timeout to half of device
0209          * max of 255 minutes...
0210          */
0211         tmrval += tmrval;
0212     }
0213
0214     if (tmrval < 1 || tmrval > 255)
0215         return -EINVAL;
0216
0217     /* timeout is the timeout in seconds, timeoutM is
0218        the timeout in minutes) */
0219     timeout = t;
0220     timeoutM = tmrval;
0221     return 0;
0222 }
0223
0224 /*
0225  * Get the watchdog status
0226  */
0227
0228 static int wdt977_get_status(int *status)
0229 {
0230     int new_status;
0231     unsigned long flags;
0232
0233     spin_lock_irqsave(&spinlock, flags);
0234
0235     /* unlock the SuperIO chip */
0236     outb_p(UNLOCK_DATA, IO_INDEX_PORT);
0237     outb_p(UNLOCK_DATA, IO_INDEX_PORT);
0238
0239     /* select device Aux2 (device=8) and read watchdog reg F4 */
0240     outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
0241     outb_p(0x08, IO_DATA_PORT);
0242     outb_p(0xF4, IO_INDEX_PORT);
0243     new_status = inb_p(IO_DATA_PORT);
0244
0245     /* lock the SuperIO chip */
0246     outb_p(LOCK_DATA, IO_INDEX_PORT);
0247
0248     spin_unlock_irqrestore(&spinlock, flags);
0249
0250     *status = 0;
0251     if (new_status & 1)
0252         *status |= WDIOF_CARDRESET;
0253
0254     return 0;
0255 }
0256
0257
0258 /*
0259  *  /dev/watchdog handling
0260  */
0261
0262 static int wdt977_open(struct inode *inode, struct file *file)
0263 {
0264     /* If the watchdog is alive we don't need to start it again */
0265     if (test_and_set_bit(0, &timer_alive))
0266         return -EBUSY;
0267
0268     if (nowayout)
0269         __module_get(THIS_MODULE);
0270
0271     wdt977_start();
0272     return stream_open(inode, file);
0273 }
0274
0275 static int wdt977_release(struct inode *inode, struct file *file)
0276 {
0277     /*
0278      *  Shut off the timer.
0279      *  Lock it in if it's a module and we set nowayout
0280      */
0281     if (expect_close == 42) {
0282         wdt977_stop();
0283         clear_bit(0, &timer_alive);
0284     } else {
0285         wdt977_keepalive();
0286         pr_crit("Unexpected close, not stopping watchdog!\n");
0287     }
0288     expect_close = 0;
0289     return 0;
0290 }
0291
0292
0293 /*
0294  *      wdt977_write:
0295  *      @file: file handle to the watchdog
0296  *      @buf: buffer to write (unused as data does not matter here
0297  *      @count: count of bytes
0298  *      @ppos: pointer to the position to write. No seeks allowed
0299  *
0300  *      A write to a watchdog device is defined as a keepalive signal. Any
0301  *      write of data will do, as we we don't define content meaning.
0302  */
0303
0304 static ssize_t wdt977_write(struct file *file, const char __user *buf,
0305                 size_t count, loff_t *ppos)
0306 {
0307     if (count) {
0308         if (!nowayout) {
0309             size_t i;
0310
0311             /* In case it was set long ago */
0312             expect_close = 0;
0313
0314             for (i = 0; i != count; i++) {
0315                 char c;
0316                 if (get_user(c, buf + i))
0317                     return -EFAULT;
0318                 if (c == 'V')
0319                     expect_close = 42;
0320             }
0321         }
0322
0323         /* someone wrote to us, we should restart timer */
0324         wdt977_keepalive();
0325     }
0326     return count;
0327 }
0328
0329 static const struct watchdog_info ident = {
0330     .options =      WDIOF_SETTIMEOUT |
0331                 WDIOF_MAGICCLOSE |
0332                 WDIOF_KEEPALIVEPING,
0333     .firmware_version = 1,
0334     .identity =     WATCHDOG_NAME,
0335 };
0336
0337 /*
0338  *      wdt977_ioctl:
0339  *      @inode: inode of the device
0340  *      @file: file handle to the device
0341  *      @cmd: watchdog command
0342  *      @arg: argument pointer
0343  *
0344  *      The watchdog API defines a common set of functions for all watchdogs
0345  *      according to their available features.
0346  */
0347
0348 static long wdt977_ioctl(struct file *file, unsigned int cmd,
0349                             unsigned long arg)
0350 {
0351     int status;
0352     int new_options, retval = -EINVAL;
0353     int new_timeout;
0354     union {
0355         struct watchdog_info __user *ident;
0356         int __user *i;
0357     } uarg;
0358
0359     uarg.i = (int __user *)arg;
0360
0361     switch (cmd) {
0362     case WDIOC_GETSUPPORT:
0363         return copy_to_user(uarg.ident, &ident,
0364             sizeof(ident)) ? -EFAULT : 0;
0365
0366     case WDIOC_GETSTATUS:
0367         wdt977_get_status(&status);
0368         return put_user(status, uarg.i);
0369
0370     case WDIOC_GETBOOTSTATUS:
0371         return put_user(0, uarg.i);
0372
0373     case WDIOC_SETOPTIONS:
0374         if (get_user(new_options, uarg.i))
0375             return -EFAULT;
0376
0377         if (new_options & WDIOS_DISABLECARD) {
0378             wdt977_stop();
0379             retval = 0;
0380         }
0381
0382         if (new_options & WDIOS_ENABLECARD) {
0383             wdt977_start();
0384             retval = 0;
0385         }
0386
0387         return retval;
0388
0389     case WDIOC_KEEPALIVE:
0390         wdt977_keepalive();
0391         return 0;
0392
0393     case WDIOC_SETTIMEOUT:
0394         if (get_user(new_timeout, uarg.i))
0395             return -EFAULT;
0396
0397         if (wdt977_set_timeout(new_timeout))
0398             return -EINVAL;
0399
0400         wdt977_keepalive();
0401         fallthrough;
0402
0403     case WDIOC_GETTIMEOUT:
0404         return put_user(timeout, uarg.i);
0405
0406     default:
0407         return -ENOTTY;
0408
0409     }
0410 }
0411
0412 static int wdt977_notify_sys(struct notifier_block *this, unsigned long code,
0413     void *unused)
0414 {
0415     if (code == SYS_DOWN || code == SYS_HALT)
0416         wdt977_stop();
0417     return NOTIFY_DONE;
0418 }
0419
0420 static const struct file_operations wdt977_fops = {
0421     .owner      = THIS_MODULE,
0422     .llseek     = no_llseek,
0423     .write      = wdt977_write,
0424     .unlocked_ioctl = wdt977_ioctl,
0425     .compat_ioctl   = compat_ptr_ioctl,
0426     .open       = wdt977_open,
0427     .release    = wdt977_release,
0428 };
0429
0430 static struct miscdevice wdt977_miscdev = {
0431     .minor      = WATCHDOG_MINOR,
0432     .name       = "watchdog",
0433     .fops       = &wdt977_fops,
0434 };
0435
0436 static struct notifier_block wdt977_notifier = {
0437     .notifier_call = wdt977_notify_sys,
0438 };
0439
0440 static int __init wd977_init(void)
0441 {
0442     int rc;
0443
0444     pr_info("driver v%s\n", WATCHDOG_VERSION);
0445
0446     /* Check that the timeout value is within its range;
0447        if not reset to the default */
0448     if (wdt977_set_timeout(timeout)) {
0449         wdt977_set_timeout(DEFAULT_TIMEOUT);
0450         pr_info("timeout value must be 60 < timeout < 15300, using %d\n",
0451             DEFAULT_TIMEOUT);
0452     }
0453
0454     /* on Netwinder the IOports are already reserved by
0455      * arch/arm/mach-footbridge/netwinder-hw.c
0456      */
0457     if (!machine_is_netwinder()) {
0458         if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
0459             pr_err("I/O address 0x%04x already in use\n",
0460                    IO_INDEX_PORT);
0461             rc = -EIO;
0462             goto err_out;
0463         }
0464     }
0465
0466     rc = register_reboot_notifier(&wdt977_notifier);
0467     if (rc) {
0468         pr_err("cannot register reboot notifier (err=%d)\n", rc);
0469         goto err_out_region;
0470     }
0471
0472     rc = misc_register(&wdt977_miscdev);
0473     if (rc) {
0474         pr_err("cannot register miscdev on minor=%d (err=%d)\n",
0475                wdt977_miscdev.minor, rc);
0476         goto err_out_reboot;
0477     }
0478
0479     pr_info("initialized. timeout=%d sec (nowayout=%d, testmode=%i)\n",
0480         timeout, nowayout, testmode);
0481
0482     return 0;
0483
0484 err_out_reboot:
0485     unregister_reboot_notifier(&wdt977_notifier);
0486 err_out_region:
0487     if (!machine_is_netwinder())
0488         release_region(IO_INDEX_PORT, 2);
0489 err_out:
0490     return rc;
0491 }
0492
0493 static void __exit wd977_exit(void)
0494 {
0495     wdt977_stop();
0496     misc_deregister(&wdt977_miscdev);
0497     unregister_reboot_notifier(&wdt977_notifier);
0498     release_region(IO_INDEX_PORT, 2);
0499 }
0500
0501 module_init(wd977_init);
0502 module_exit(wd977_exit);
0503
0504 MODULE_AUTHOR("Woody Suwalski <woodys@xandros.com>");
0505 MODULE_DESCRIPTION("W83977AF Watchdog driver");
0506 MODULE_LICENSE("GPL");