1 /* 2 * Advantech Single Board Computer WDT driver 3 * 4 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl> 5 * 6 * Based on acquirewdt.c which is based on wdt.c. 7 * Original copyright messages: 8 * 9 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, 10 * All Rights Reserved. 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 * 17 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide 18 * warranty for any of this software. This material is provided 19 * "AS-IS" and at no charge. 20 * 21 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> 22 * 23 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> 24 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT 25 * 26 * 16-Oct-2002 Rob Radez <rob@osinvestor.com> 27 * Clean up ioctls, clean up init + exit, add expect close support, 28 * add wdt_start and wdt_stop as parameters. 29 */ 30 31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 32 33 #include <linux/module.h> 34 #include <linux/moduleparam.h> 35 #include <linux/types.h> 36 #include <linux/miscdevice.h> 37 #include <linux/watchdog.h> 38 #include <linux/fs.h> 39 #include <linux/ioport.h> 40 #include <linux/platform_device.h> 41 #include <linux/init.h> 42 #include <linux/io.h> 43 #include <linux/uaccess.h> 44 45 46 #define DRV_NAME "advantechwdt" 47 #define WATCHDOG_NAME "Advantech WDT" 48 #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ 49 50 /* the watchdog platform device */ 51 static struct platform_device *advwdt_platform_device; 52 static unsigned long advwdt_is_open; 53 static char adv_expect_close; 54 55 /* 56 * You must set these - there is no sane way to probe for this board. 57 * 58 * To enable or restart, write the timeout value in seconds (1 to 63) 59 * to I/O port wdt_start. To disable, read I/O port wdt_stop. 60 * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but 61 * check your manual (at least the PCA-6159 seems to be different - 62 * the manual says wdt_stop is 0x43, not 0x443). 63 * (0x43 is also a write-only control register for the 8254 timer!) 64 */ 65 66 static int wdt_stop = 0x443; 67 module_param(wdt_stop, int, 0); 68 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)"); 69 70 static int wdt_start = 0x443; 71 module_param(wdt_start, int, 0); 72 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)"); 73 74 static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ 75 module_param(timeout, int, 0); 76 MODULE_PARM_DESC(timeout, 77 "Watchdog timeout in seconds. 1<= timeout <=63, default=" 78 __MODULE_STRING(WATCHDOG_TIMEOUT) "."); 79 80 static bool nowayout = WATCHDOG_NOWAYOUT; 81 module_param(nowayout, bool, 0); 82 MODULE_PARM_DESC(nowayout, 83 "Watchdog cannot be stopped once started (default=" 84 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 85 86 /* 87 * Watchdog Operations 88 */ 89 90 static void advwdt_ping(void) 91 { 92 /* Write a watchdog value */ 93 outb_p(timeout, wdt_start); 94 } 95 96 static void advwdt_disable(void) 97 { 98 inb_p(wdt_stop); 99 } 100 101 static int advwdt_set_heartbeat(int t) 102 { 103 if (t < 1 || t > 63) 104 return -EINVAL; 105 timeout = t; 106 return 0; 107 } 108 109 /* 110 * /dev/watchdog handling 111 */ 112 113 static ssize_t advwdt_write(struct file *file, const char __user *buf, 114 size_t count, loff_t *ppos) 115 { 116 if (count) { 117 if (!nowayout) { 118 size_t i; 119 120 adv_expect_close = 0; 121 122 for (i = 0; i != count; i++) { 123 char c; 124 if (get_user(c, buf + i)) 125 return -EFAULT; 126 if (c == 'V') 127 adv_expect_close = 42; 128 } 129 } 130 advwdt_ping(); 131 } 132 return count; 133 } 134 135 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 136 { 137 int new_timeout; 138 void __user *argp = (void __user *)arg; 139 int __user *p = argp; 140 static const struct watchdog_info ident = { 141 .options = WDIOF_KEEPALIVEPING | 142 WDIOF_SETTIMEOUT | 143 WDIOF_MAGICCLOSE, 144 .firmware_version = 1, 145 .identity = WATCHDOG_NAME, 146 }; 147 148 switch (cmd) { 149 case WDIOC_GETSUPPORT: 150 if (copy_to_user(argp, &ident, sizeof(ident))) 151 return -EFAULT; 152 break; 153 154 case WDIOC_GETSTATUS: 155 case WDIOC_GETBOOTSTATUS: 156 return put_user(0, p); 157 158 case WDIOC_SETOPTIONS: 159 { 160 int options, retval = -EINVAL; 161 162 if (get_user(options, p)) 163 return -EFAULT; 164 if (options & WDIOS_DISABLECARD) { 165 advwdt_disable(); 166 retval = 0; 167 } 168 if (options & WDIOS_ENABLECARD) { 169 advwdt_ping(); 170 retval = 0; 171 } 172 return retval; 173 } 174 case WDIOC_KEEPALIVE: 175 advwdt_ping(); 176 break; 177 178 case WDIOC_SETTIMEOUT: 179 if (get_user(new_timeout, p)) 180 return -EFAULT; 181 if (advwdt_set_heartbeat(new_timeout)) 182 return -EINVAL; 183 advwdt_ping(); 184 /* Fall */ 185 case WDIOC_GETTIMEOUT: 186 return put_user(timeout, p); 187 default: 188 return -ENOTTY; 189 } 190 return 0; 191 } 192 193 static int advwdt_open(struct inode *inode, struct file *file) 194 { 195 if (test_and_set_bit(0, &advwdt_is_open)) 196 return -EBUSY; 197 /* 198 * Activate 199 */ 200 201 advwdt_ping(); 202 return nonseekable_open(inode, file); 203 } 204 205 static int advwdt_close(struct inode *inode, struct file *file) 206 { 207 if (adv_expect_close == 42) { 208 advwdt_disable(); 209 } else { 210 pr_crit("Unexpected close, not stopping watchdog!\n"); 211 advwdt_ping(); 212 } 213 clear_bit(0, &advwdt_is_open); 214 adv_expect_close = 0; 215 return 0; 216 } 217 218 /* 219 * Kernel Interfaces 220 */ 221 222 static const struct file_operations advwdt_fops = { 223 .owner = THIS_MODULE, 224 .llseek = no_llseek, 225 .write = advwdt_write, 226 .unlocked_ioctl = advwdt_ioctl, 227 .open = advwdt_open, 228 .release = advwdt_close, 229 }; 230 231 static struct miscdevice advwdt_miscdev = { 232 .minor = WATCHDOG_MINOR, 233 .name = "watchdog", 234 .fops = &advwdt_fops, 235 }; 236 237 /* 238 * Init & exit routines 239 */ 240 241 static int __init advwdt_probe(struct platform_device *dev) 242 { 243 int ret; 244 245 if (wdt_stop != wdt_start) { 246 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { 247 pr_err("I/O address 0x%04x already in use\n", 248 wdt_stop); 249 ret = -EIO; 250 goto out; 251 } 252 } 253 254 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { 255 pr_err("I/O address 0x%04x already in use\n", wdt_start); 256 ret = -EIO; 257 goto unreg_stop; 258 } 259 260 /* Check that the heartbeat value is within it's range ; 261 * if not reset to the default */ 262 if (advwdt_set_heartbeat(timeout)) { 263 advwdt_set_heartbeat(WATCHDOG_TIMEOUT); 264 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout); 265 } 266 267 ret = misc_register(&advwdt_miscdev); 268 if (ret != 0) { 269 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 270 WATCHDOG_MINOR, ret); 271 goto unreg_regions; 272 } 273 pr_info("initialized. timeout=%d sec (nowayout=%d)\n", 274 timeout, nowayout); 275 out: 276 return ret; 277 unreg_regions: 278 release_region(wdt_start, 1); 279 unreg_stop: 280 if (wdt_stop != wdt_start) 281 release_region(wdt_stop, 1); 282 goto out; 283 } 284 285 static int advwdt_remove(struct platform_device *dev) 286 { 287 misc_deregister(&advwdt_miscdev); 288 release_region(wdt_start, 1); 289 if (wdt_stop != wdt_start) 290 release_region(wdt_stop, 1); 291 292 return 0; 293 } 294 295 static void advwdt_shutdown(struct platform_device *dev) 296 { 297 /* Turn the WDT off if we have a soft shutdown */ 298 advwdt_disable(); 299 } 300 301 static struct platform_driver advwdt_driver = { 302 .remove = advwdt_remove, 303 .shutdown = advwdt_shutdown, 304 .driver = { 305 .name = DRV_NAME, 306 }, 307 }; 308 309 static int __init advwdt_init(void) 310 { 311 int err; 312 313 pr_info("WDT driver for Advantech single board computer initialising\n"); 314 315 advwdt_platform_device = platform_device_register_simple(DRV_NAME, 316 -1, NULL, 0); 317 if (IS_ERR(advwdt_platform_device)) 318 return PTR_ERR(advwdt_platform_device); 319 320 err = platform_driver_probe(&advwdt_driver, advwdt_probe); 321 if (err) 322 goto unreg_platform_device; 323 324 return 0; 325 326 unreg_platform_device: 327 platform_device_unregister(advwdt_platform_device); 328 return err; 329 } 330 331 static void __exit advwdt_exit(void) 332 { 333 platform_device_unregister(advwdt_platform_device); 334 platform_driver_unregister(&advwdt_driver); 335 pr_info("Watchdog Module Unloaded\n"); 336 } 337 338 module_init(advwdt_init); 339 module_exit(advwdt_exit); 340 341 MODULE_LICENSE("GPL"); 342 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>"); 343 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver"); 344