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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Advantech Single Board Computer WDT driver4 *5 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>6 *7 * Based on acquirewdt.c which is based on wdt.c.8 * Original copyright messages:9 *10 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,11 * All Rights Reserved.12 *13 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide14 * warranty for any of this software. This material is provided15 * "AS-IS" and at no charge.16 *17 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>18 *19 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>20 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT21 *22 * 16-Oct-2002 Rob Radez <rob@osinvestor.com>23 * Clean up ioctls, clean up init + exit, add expect close support,24 * add wdt_start and wdt_stop as parameters.25 */26 27#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt28 29#include <linux/module.h>30#include <linux/moduleparam.h>31#include <linux/types.h>32#include <linux/miscdevice.h>33#include <linux/watchdog.h>34#include <linux/fs.h>35#include <linux/ioport.h>36#include <linux/platform_device.h>37#include <linux/init.h>38#include <linux/io.h>39#include <linux/uaccess.h>40 41 42#define DRV_NAME "advantechwdt"43#define WATCHDOG_NAME "Advantech WDT"44#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */45 46/* the watchdog platform device */47static struct platform_device *advwdt_platform_device;48static unsigned long advwdt_is_open;49static char adv_expect_close;50 51/*52 * You must set these - there is no sane way to probe for this board.53 *54 * To enable or restart, write the timeout value in seconds (1 to 63)55 * to I/O port wdt_start. To disable, read I/O port wdt_stop.56 * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but57 * check your manual (at least the PCA-6159 seems to be different -58 * the manual says wdt_stop is 0x43, not 0x443).59 * (0x43 is also a write-only control register for the 8254 timer!)60 */61 62static int wdt_stop = 0x443;63module_param(wdt_stop, int, 0);64MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");65 66static int wdt_start = 0x443;67module_param(wdt_start, int, 0);68MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");69 70static int timeout = WATCHDOG_TIMEOUT; /* in seconds */71module_param(timeout, int, 0);72MODULE_PARM_DESC(timeout,73 "Watchdog timeout in seconds. 1<= timeout <=63, default="74 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");75 76static bool nowayout = WATCHDOG_NOWAYOUT;77module_param(nowayout, bool, 0);78MODULE_PARM_DESC(nowayout,79 "Watchdog cannot be stopped once started (default="80 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");81 82/*83 * Watchdog Operations84 */85 86static void advwdt_ping(void)87{88 /* Write a watchdog value */89 outb_p(timeout, wdt_start);90}91 92static void advwdt_disable(void)93{94 inb_p(wdt_stop);95}96 97static int advwdt_set_heartbeat(int t)98{99 if (t < 1 || t > 63)100 return -EINVAL;101 timeout = t;102 return 0;103}104 105/*106 * /dev/watchdog handling107 */108 109static ssize_t advwdt_write(struct file *file, const char __user *buf,110 size_t count, loff_t *ppos)111{112 if (count) {113 if (!nowayout) {114 size_t i;115 116 adv_expect_close = 0;117 118 for (i = 0; i != count; i++) {119 char c;120 if (get_user(c, buf + i))121 return -EFAULT;122 if (c == 'V')123 adv_expect_close = 42;124 }125 }126 advwdt_ping();127 }128 return count;129}130 131static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)132{133 int new_timeout;134 void __user *argp = (void __user *)arg;135 int __user *p = argp;136 static const struct watchdog_info ident = {137 .options = WDIOF_KEEPALIVEPING |138 WDIOF_SETTIMEOUT |139 WDIOF_MAGICCLOSE,140 .firmware_version = 1,141 .identity = WATCHDOG_NAME,142 };143 144 switch (cmd) {145 case WDIOC_GETSUPPORT:146 if (copy_to_user(argp, &ident, sizeof(ident)))147 return -EFAULT;148 break;149 150 case WDIOC_GETSTATUS:151 case WDIOC_GETBOOTSTATUS:152 return put_user(0, p);153 154 case WDIOC_SETOPTIONS:155 {156 int options, retval = -EINVAL;157 158 if (get_user(options, p))159 return -EFAULT;160 if (options & WDIOS_DISABLECARD) {161 advwdt_disable();162 retval = 0;163 }164 if (options & WDIOS_ENABLECARD) {165 advwdt_ping();166 retval = 0;167 }168 return retval;169 }170 case WDIOC_KEEPALIVE:171 advwdt_ping();172 break;173 174 case WDIOC_SETTIMEOUT:175 if (get_user(new_timeout, p))176 return -EFAULT;177 if (advwdt_set_heartbeat(new_timeout))178 return -EINVAL;179 advwdt_ping();180 fallthrough;181 case WDIOC_GETTIMEOUT:182 return put_user(timeout, p);183 default:184 return -ENOTTY;185 }186 return 0;187}188 189static int advwdt_open(struct inode *inode, struct file *file)190{191 if (test_and_set_bit(0, &advwdt_is_open))192 return -EBUSY;193 /*194 * Activate195 */196 197 advwdt_ping();198 return stream_open(inode, file);199}200 201static int advwdt_close(struct inode *inode, struct file *file)202{203 if (adv_expect_close == 42) {204 advwdt_disable();205 } else {206 pr_crit("Unexpected close, not stopping watchdog!\n");207 advwdt_ping();208 }209 clear_bit(0, &advwdt_is_open);210 adv_expect_close = 0;211 return 0;212}213 214/*215 * Kernel Interfaces216 */217 218static const struct file_operations advwdt_fops = {219 .owner = THIS_MODULE,220 .write = advwdt_write,221 .unlocked_ioctl = advwdt_ioctl,222 .compat_ioctl = compat_ptr_ioctl,223 .open = advwdt_open,224 .release = advwdt_close,225};226 227static struct miscdevice advwdt_miscdev = {228 .minor = WATCHDOG_MINOR,229 .name = "watchdog",230 .fops = &advwdt_fops,231};232 233/*234 * Init & exit routines235 */236 237static int __init advwdt_probe(struct platform_device *dev)238{239 int ret;240 241 if (wdt_stop != wdt_start) {242 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {243 pr_err("I/O address 0x%04x already in use\n",244 wdt_stop);245 ret = -EIO;246 goto out;247 }248 }249 250 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {251 pr_err("I/O address 0x%04x already in use\n", wdt_start);252 ret = -EIO;253 goto unreg_stop;254 }255 256 /* Check that the heartbeat value is within it's range ;257 * if not reset to the default */258 if (advwdt_set_heartbeat(timeout)) {259 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);260 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);261 }262 263 ret = misc_register(&advwdt_miscdev);264 if (ret != 0) {265 pr_err("cannot register miscdev on minor=%d (err=%d)\n",266 WATCHDOG_MINOR, ret);267 goto unreg_regions;268 }269 pr_info("initialized. timeout=%d sec (nowayout=%d)\n",270 timeout, nowayout);271out:272 return ret;273unreg_regions:274 release_region(wdt_start, 1);275unreg_stop:276 if (wdt_stop != wdt_start)277 release_region(wdt_stop, 1);278 goto out;279}280 281static void advwdt_remove(struct platform_device *dev)282{283 misc_deregister(&advwdt_miscdev);284 release_region(wdt_start, 1);285 if (wdt_stop != wdt_start)286 release_region(wdt_stop, 1);287}288 289static void advwdt_shutdown(struct platform_device *dev)290{291 /* Turn the WDT off if we have a soft shutdown */292 advwdt_disable();293}294 295static struct platform_driver advwdt_driver = {296 .remove_new = advwdt_remove,297 .shutdown = advwdt_shutdown,298 .driver = {299 .name = DRV_NAME,300 },301};302 303static int __init advwdt_init(void)304{305 int err;306 307 pr_info("WDT driver for Advantech single board computer initialising\n");308 309 advwdt_platform_device = platform_device_register_simple(DRV_NAME,310 -1, NULL, 0);311 if (IS_ERR(advwdt_platform_device))312 return PTR_ERR(advwdt_platform_device);313 314 err = platform_driver_probe(&advwdt_driver, advwdt_probe);315 if (err)316 goto unreg_platform_device;317 318 return 0;319 320unreg_platform_device:321 platform_device_unregister(advwdt_platform_device);322 return err;323}324 325static void __exit advwdt_exit(void)326{327 platform_device_unregister(advwdt_platform_device);328 platform_driver_unregister(&advwdt_driver);329 pr_info("Watchdog Module Unloaded\n");330}331 332module_init(advwdt_init);333module_exit(advwdt_exit);334 335MODULE_LICENSE("GPL");336MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");337MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");338