drivers/watchdog/advantechwdt.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  *  Advantech Single Board Computer WDT driver
0004  *
0005  *  (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
0006  *
0007  *  Based on acquirewdt.c which is based on wdt.c.
0008  *  Original copyright messages:
0009  *
0010  *  (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
0011  *                      All Rights Reserved.
0012  *
0013  *  Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
0014  *  warranty for any of this software. This material is provided
0015  *  "AS-IS" and at no charge.
0016  *
0017  *  (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
0018  *
0019  *  14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
0020  *      Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
0021  *
0022  *  16-Oct-2002 Rob Radez <rob@osinvestor.com>
0023  *      Clean up ioctls, clean up init + exit, add expect close support,
0024  *      add wdt_start and wdt_stop as parameters.
0025  */
0026
0027 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0028
0029 #include <linux/module.h>
0030 #include <linux/moduleparam.h>
0031 #include <linux/types.h>
0032 #include <linux/miscdevice.h>
0033 #include <linux/watchdog.h>
0034 #include <linux/fs.h>
0035 #include <linux/ioport.h>
0036 #include <linux/platform_device.h>
0037 #include <linux/init.h>
0038 #include <linux/io.h>
0039 #include <linux/uaccess.h>
0040
0041
0042 #define DRV_NAME "advantechwdt"
0043 #define WATCHDOG_NAME "Advantech WDT"
0044 #define WATCHDOG_TIMEOUT 60     /* 60 sec default timeout */
0045
0046 /* the watchdog platform device */
0047 static struct platform_device *advwdt_platform_device;
0048 static unsigned long advwdt_is_open;
0049 static char adv_expect_close;
0050
0051 /*
0052  *  You must set these - there is no sane way to probe for this board.
0053  *
0054  *  To enable or restart, write the timeout value in seconds (1 to 63)
0055  *  to I/O port wdt_start.  To disable, read I/O port wdt_stop.
0056  *  Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
0057  *  check your manual (at least the PCA-6159 seems to be different -
0058  *  the manual says wdt_stop is 0x43, not 0x443).
0059  *  (0x43 is also a write-only control register for the 8254 timer!)
0060  */
0061
0062 static int wdt_stop = 0x443;
0063 module_param(wdt_stop, int, 0);
0064 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
0065
0066 static int wdt_start = 0x443;
0067 module_param(wdt_start, int, 0);
0068 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
0069
0070 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
0071 module_param(timeout, int, 0);
0072 MODULE_PARM_DESC(timeout,
0073     "Watchdog timeout in seconds. 1<= timeout <=63, default="
0074         __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
0075
0076 static bool nowayout = WATCHDOG_NOWAYOUT;
0077 module_param(nowayout, bool, 0);
0078 MODULE_PARM_DESC(nowayout,
0079     "Watchdog cannot be stopped once started (default="
0080         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
0081
0082 /*
0083  *  Watchdog Operations
0084  */
0085
0086 static void advwdt_ping(void)
0087 {
0088     /* Write a watchdog value */
0089     outb_p(timeout, wdt_start);
0090 }
0091
0092 static void advwdt_disable(void)
0093 {
0094     inb_p(wdt_stop);
0095 }
0096
0097 static int advwdt_set_heartbeat(int t)
0098 {
0099     if (t < 1 || t > 63)
0100         return -EINVAL;
0101     timeout = t;
0102     return 0;
0103 }
0104
0105 /*
0106  *  /dev/watchdog handling
0107  */
0108
0109 static ssize_t advwdt_write(struct file *file, const char __user *buf,
0110                         size_t count, loff_t *ppos)
0111 {
0112     if (count) {
0113         if (!nowayout) {
0114             size_t i;
0115
0116             adv_expect_close = 0;
0117
0118             for (i = 0; i != count; i++) {
0119                 char c;
0120                 if (get_user(c, buf + i))
0121                     return -EFAULT;
0122                 if (c == 'V')
0123                     adv_expect_close = 42;
0124             }
0125         }
0126         advwdt_ping();
0127     }
0128     return count;
0129 }
0130
0131 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
0132 {
0133     int new_timeout;
0134     void __user *argp = (void __user *)arg;
0135     int __user *p = argp;
0136     static const struct watchdog_info ident = {
0137         .options = WDIOF_KEEPALIVEPING |
0138                WDIOF_SETTIMEOUT |
0139                WDIOF_MAGICCLOSE,
0140         .firmware_version = 1,
0141         .identity = WATCHDOG_NAME,
0142     };
0143
0144     switch (cmd) {
0145     case WDIOC_GETSUPPORT:
0146         if (copy_to_user(argp, &ident, sizeof(ident)))
0147             return -EFAULT;
0148         break;
0149
0150     case WDIOC_GETSTATUS:
0151     case WDIOC_GETBOOTSTATUS:
0152         return put_user(0, p);
0153
0154     case WDIOC_SETOPTIONS:
0155     {
0156         int options, retval = -EINVAL;
0157
0158         if (get_user(options, p))
0159             return -EFAULT;
0160         if (options & WDIOS_DISABLECARD) {
0161             advwdt_disable();
0162             retval = 0;
0163         }
0164         if (options & WDIOS_ENABLECARD) {
0165             advwdt_ping();
0166             retval = 0;
0167         }
0168         return retval;
0169     }
0170     case WDIOC_KEEPALIVE:
0171         advwdt_ping();
0172         break;
0173
0174     case WDIOC_SETTIMEOUT:
0175         if (get_user(new_timeout, p))
0176             return -EFAULT;
0177         if (advwdt_set_heartbeat(new_timeout))
0178             return -EINVAL;
0179         advwdt_ping();
0180         fallthrough;
0181     case WDIOC_GETTIMEOUT:
0182         return put_user(timeout, p);
0183     default:
0184         return -ENOTTY;
0185     }
0186     return 0;
0187 }
0188
0189 static int advwdt_open(struct inode *inode, struct file *file)
0190 {
0191     if (test_and_set_bit(0, &advwdt_is_open))
0192         return -EBUSY;
0193     /*
0194      *  Activate
0195      */
0196
0197     advwdt_ping();
0198     return stream_open(inode, file);
0199 }
0200
0201 static int advwdt_close(struct inode *inode, struct file *file)
0202 {
0203     if (adv_expect_close == 42) {
0204         advwdt_disable();
0205     } else {
0206         pr_crit("Unexpected close, not stopping watchdog!\n");
0207         advwdt_ping();
0208     }
0209     clear_bit(0, &advwdt_is_open);
0210     adv_expect_close = 0;
0211     return 0;
0212 }
0213
0214 /*
0215  *  Kernel Interfaces
0216  */
0217
0218 static const struct file_operations advwdt_fops = {
0219     .owner      = THIS_MODULE,
0220     .llseek     = no_llseek,
0221     .write      = advwdt_write,
0222     .unlocked_ioctl = advwdt_ioctl,
0223     .compat_ioctl   = compat_ptr_ioctl,
0224     .open       = advwdt_open,
0225     .release    = advwdt_close,
0226 };
0227
0228 static struct miscdevice advwdt_miscdev = {
0229     .minor  = WATCHDOG_MINOR,
0230     .name   = "watchdog",
0231     .fops   = &advwdt_fops,
0232 };
0233
0234 /*
0235  *  Init & exit routines
0236  */
0237
0238 static int __init advwdt_probe(struct platform_device *dev)
0239 {
0240     int ret;
0241
0242     if (wdt_stop != wdt_start) {
0243         if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
0244             pr_err("I/O address 0x%04x already in use\n",
0245                    wdt_stop);
0246             ret = -EIO;
0247             goto out;
0248         }
0249     }
0250
0251     if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
0252         pr_err("I/O address 0x%04x already in use\n", wdt_start);
0253         ret = -EIO;
0254         goto unreg_stop;
0255     }
0256
0257     /* Check that the heartbeat value is within it's range ;
0258      * if not reset to the default */
0259     if (advwdt_set_heartbeat(timeout)) {
0260         advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
0261         pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
0262     }
0263
0264     ret = misc_register(&advwdt_miscdev);
0265     if (ret != 0) {
0266         pr_err("cannot register miscdev on minor=%d (err=%d)\n",
0267                WATCHDOG_MINOR, ret);
0268         goto unreg_regions;
0269     }
0270     pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
0271         timeout, nowayout);
0272 out:
0273     return ret;
0274 unreg_regions:
0275     release_region(wdt_start, 1);
0276 unreg_stop:
0277     if (wdt_stop != wdt_start)
0278         release_region(wdt_stop, 1);
0279     goto out;
0280 }
0281
0282 static int advwdt_remove(struct platform_device *dev)
0283 {
0284     misc_deregister(&advwdt_miscdev);
0285     release_region(wdt_start, 1);
0286     if (wdt_stop != wdt_start)
0287         release_region(wdt_stop, 1);
0288
0289     return 0;
0290 }
0291
0292 static void advwdt_shutdown(struct platform_device *dev)
0293 {
0294     /* Turn the WDT off if we have a soft shutdown */
0295     advwdt_disable();
0296 }
0297
0298 static struct platform_driver advwdt_driver = {
0299     .remove     = advwdt_remove,
0300     .shutdown   = advwdt_shutdown,
0301     .driver     = {
0302         .name   = DRV_NAME,
0303     },
0304 };
0305
0306 static int __init advwdt_init(void)
0307 {
0308     int err;
0309
0310     pr_info("WDT driver for Advantech single board computer initialising\n");
0311
0312     advwdt_platform_device = platform_device_register_simple(DRV_NAME,
0313                                 -1, NULL, 0);
0314     if (IS_ERR(advwdt_platform_device))
0315         return PTR_ERR(advwdt_platform_device);
0316
0317     err = platform_driver_probe(&advwdt_driver, advwdt_probe);
0318     if (err)
0319         goto unreg_platform_device;
0320
0321     return 0;
0322
0323 unreg_platform_device:
0324     platform_device_unregister(advwdt_platform_device);
0325     return err;
0326 }
0327
0328 static void __exit advwdt_exit(void)
0329 {
0330     platform_device_unregister(advwdt_platform_device);
0331     platform_driver_unregister(&advwdt_driver);
0332     pr_info("Watchdog Module Unloaded\n");
0333 }
0334
0335 module_init(advwdt_init);
0336 module_exit(advwdt_exit);
0337
0338 MODULE_LICENSE("GPL");
0339 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
0340 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");