1 /* 2 * ICP Wafer 5823 Single Board Computer WDT driver 3 * http://www.icpamerica.com/wafer_5823.php 4 * May also work on other similar models 5 * 6 * (c) Copyright 2002 Justin Cormack <justin@street-vision.com> 7 * 8 * Release 0.02 9 * 10 * Based on advantechwdt.c which is based on wdt.c. 11 * Original copyright messages: 12 * 13 * (c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved. 14 * http://www.redhat.com 15 * 16 * This program is free software; you can redistribute it and/or 17 * modify it under the terms of the GNU General Public License 18 * as published by the Free Software Foundation; either version 19 * 2 of the License, or (at your option) any later version. 20 * 21 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide 22 * warranty for any of this software. This material is provided 23 * "AS-IS" and at no charge. 24 * 25 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> 26 * 27 */ 28 29 #include <linux/module.h> 30 #include <linux/moduleparam.h> 31 #include <linux/miscdevice.h> 32 #include <linux/watchdog.h> 33 #include <linux/fs.h> 34 #include <linux/ioport.h> 35 #include <linux/notifier.h> 36 #include <linux/reboot.h> 37 #include <linux/init.h> 38 #include <linux/spinlock.h> 39 #include <asm/io.h> 40 #include <asm/uaccess.h> 41 42 #define WATCHDOG_NAME "Wafer 5823 WDT" 43 #define PFX WATCHDOG_NAME ": " 44 #define WD_TIMO 60 /* 60 sec default timeout */ 45 46 static unsigned long wafwdt_is_open; 47 static char expect_close; 48 static DEFINE_SPINLOCK(wafwdt_lock); 49 50 /* 51 * You must set these - there is no sane way to probe for this board. 52 * 53 * To enable, write the timeout value in seconds (1 to 255) to I/O 54 * port WDT_START, then read the port to start the watchdog. To pat 55 * the dog, read port WDT_STOP to stop the timer, then read WDT_START 56 * to restart it again. 57 */ 58 59 static int wdt_stop = 0x843; 60 static int wdt_start = 0x443; 61 62 static int timeout = WD_TIMO; /* in seconds */ 63 module_param(timeout, int, 0); 64 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=255, default=" __MODULE_STRING(WD_TIMO) "."); 65 66 static int nowayout = WATCHDOG_NOWAYOUT; 67 module_param(nowayout, int, 0); 68 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 69 70 static void wafwdt_ping(void) 71 { 72 /* pat watchdog */ 73 spin_lock(&wafwdt_lock); 74 inb_p(wdt_stop); 75 inb_p(wdt_start); 76 spin_unlock(&wafwdt_lock); 77 } 78 79 static void wafwdt_start(void) 80 { 81 /* start up watchdog */ 82 outb_p(timeout, wdt_start); 83 inb_p(wdt_start); 84 } 85 86 static void 87 wafwdt_stop(void) 88 { 89 /* stop watchdog */ 90 inb_p(wdt_stop); 91 } 92 93 static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos) 94 { 95 /* See if we got the magic character 'V' and reload the timer */ 96 if (count) { 97 if (!nowayout) { 98 size_t i; 99 100 /* In case it was set long ago */ 101 expect_close = 0; 102 103 /* scan to see whether or not we got the magic character */ 104 for (i = 0; i != count; i++) { 105 char c; 106 if (get_user(c, buf + i)) 107 return -EFAULT; 108 if (c == 'V') 109 expect_close = 42; 110 } 111 } 112 /* Well, anyhow someone wrote to us, we should return that favour */ 113 wafwdt_ping(); 114 } 115 return count; 116 } 117 118 static int wafwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, 119 unsigned long arg) 120 { 121 int new_timeout; 122 void __user *argp = (void __user *)arg; 123 int __user *p = argp; 124 static struct watchdog_info ident = { 125 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, 126 .firmware_version = 1, 127 .identity = "Wafer 5823 WDT", 128 }; 129 130 switch (cmd) { 131 case WDIOC_GETSUPPORT: 132 if (copy_to_user(argp, &ident, sizeof (ident))) 133 return -EFAULT; 134 break; 135 136 case WDIOC_GETSTATUS: 137 case WDIOC_GETBOOTSTATUS: 138 return put_user(0, p); 139 140 case WDIOC_KEEPALIVE: 141 wafwdt_ping(); 142 break; 143 144 case WDIOC_SETTIMEOUT: 145 if (get_user(new_timeout, p)) 146 return -EFAULT; 147 if ((new_timeout < 1) || (new_timeout > 255)) 148 return -EINVAL; 149 timeout = new_timeout; 150 wafwdt_stop(); 151 wafwdt_start(); 152 /* Fall */ 153 case WDIOC_GETTIMEOUT: 154 return put_user(timeout, p); 155 156 case WDIOC_SETOPTIONS: 157 { 158 int options, retval = -EINVAL; 159 160 if (get_user(options, p)) 161 return -EFAULT; 162 163 if (options & WDIOS_DISABLECARD) { 164 wafwdt_start(); 165 retval = 0; 166 } 167 168 if (options & WDIOS_ENABLECARD) { 169 wafwdt_stop(); 170 retval = 0; 171 } 172 173 return retval; 174 } 175 176 default: 177 return -ENOTTY; 178 } 179 return 0; 180 } 181 182 static int wafwdt_open(struct inode *inode, struct file *file) 183 { 184 if (test_and_set_bit(0, &wafwdt_is_open)) 185 return -EBUSY; 186 187 /* 188 * Activate 189 */ 190 wafwdt_start(); 191 return nonseekable_open(inode, file); 192 } 193 194 static int 195 wafwdt_close(struct inode *inode, struct file *file) 196 { 197 if (expect_close == 42) { 198 wafwdt_stop(); 199 } else { 200 printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n"); 201 wafwdt_ping(); 202 } 203 clear_bit(0, &wafwdt_is_open); 204 expect_close = 0; 205 return 0; 206 } 207 208 /* 209 * Notifier for system down 210 */ 211 212 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) 213 { 214 if (code == SYS_DOWN || code == SYS_HALT) { 215 /* Turn the WDT off */ 216 wafwdt_stop(); 217 } 218 return NOTIFY_DONE; 219 } 220 221 /* 222 * Kernel Interfaces 223 */ 224 225 static const struct file_operations wafwdt_fops = { 226 .owner = THIS_MODULE, 227 .llseek = no_llseek, 228 .write = wafwdt_write, 229 .ioctl = wafwdt_ioctl, 230 .open = wafwdt_open, 231 .release = wafwdt_close, 232 }; 233 234 static struct miscdevice wafwdt_miscdev = { 235 .minor = WATCHDOG_MINOR, 236 .name = "watchdog", 237 .fops = &wafwdt_fops, 238 }; 239 240 /* 241 * The WDT needs to learn about soft shutdowns in order to 242 * turn the timebomb registers off. 243 */ 244 245 static struct notifier_block wafwdt_notifier = { 246 .notifier_call = wafwdt_notify_sys, 247 }; 248 249 static int __init wafwdt_init(void) 250 { 251 int ret; 252 253 printk(KERN_INFO "WDT driver for Wafer 5823 single board computer initialising.\n"); 254 255 if (timeout < 1 || timeout > 255) { 256 timeout = WD_TIMO; 257 printk (KERN_INFO PFX "timeout value must be 1<=x<=255, using %d\n", 258 timeout); 259 } 260 261 if (wdt_stop != wdt_start) { 262 if(!request_region(wdt_stop, 1, "Wafer 5823 WDT")) { 263 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", 264 wdt_stop); 265 ret = -EIO; 266 goto error; 267 } 268 } 269 270 if(!request_region(wdt_start, 1, "Wafer 5823 WDT")) { 271 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", 272 wdt_start); 273 ret = -EIO; 274 goto error2; 275 } 276 277 ret = register_reboot_notifier(&wafwdt_notifier); 278 if (ret != 0) { 279 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", 280 ret); 281 goto error3; 282 } 283 284 ret = misc_register(&wafwdt_miscdev); 285 if (ret != 0) { 286 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", 287 WATCHDOG_MINOR, ret); 288 goto error4; 289 } 290 291 printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n", 292 timeout, nowayout); 293 294 return ret; 295 error4: 296 unregister_reboot_notifier(&wafwdt_notifier); 297 error3: 298 release_region(wdt_start, 1); 299 error2: 300 if (wdt_stop != wdt_start) 301 release_region(wdt_stop, 1); 302 error: 303 return ret; 304 } 305 306 static void __exit wafwdt_exit(void) 307 { 308 misc_deregister(&wafwdt_miscdev); 309 unregister_reboot_notifier(&wafwdt_notifier); 310 if(wdt_stop != wdt_start) 311 release_region(wdt_stop, 1); 312 release_region(wdt_start, 1); 313 } 314 315 module_init(wafwdt_init); 316 module_exit(wafwdt_exit); 317 318 MODULE_AUTHOR("Justin Cormack"); 319 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver"); 320 MODULE_LICENSE("GPL"); 321 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 322 323 /* end of wafer5823wdt.c */ 324