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#include <linux/module.h> 32#include <linux/moduleparam.h> 33#include <linux/types.h> 34#include <linux/miscdevice.h> 35#include <linux/watchdog.h> 36#include <linux/fs.h> 37#include <linux/ioport.h> 38#include <linux/platform_device.h> 39#include <linux/init.h> 40#include <linux/io.h> 41#include <linux/uaccess.h> 42 43#include <asm/system.h> 44 45#define DRV_NAME "advantechwdt" 46#define PFX DRV_NAME ": " 47#define WATCHDOG_NAME "Advantech WDT" 48#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ 49 50/* the watchdog platform device */ 51static struct platform_device *advwdt_platform_device; 52static unsigned long advwdt_is_open; 53static 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 66static int wdt_stop = 0x443; 67module_param(wdt_stop, int, 0); 68MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)"); 69 70static int wdt_start = 0x443; 71module_param(wdt_start, int, 0); 72MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)"); 73 74static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ 75module_param(timeout, int, 0); 76MODULE_PARM_DESC(timeout, 77 "Watchdog timeout in seconds. 1<= timeout <=63, default=" 78 __MODULE_STRING(WATCHDOG_TIMEOUT) "."); 79 80static int nowayout = WATCHDOG_NOWAYOUT; 81module_param(nowayout, int, 0); 82MODULE_PARM_DESC(nowayout, 83 "Watchdog cannot be stopped once started (default=" 84 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 85 86/* 87 * Watchdog Operations 88 */ 89 90static void advwdt_ping(void) 91{ 92 /* Write a watchdog value */ 93 outb_p(timeout, wdt_start); 94} 95 96static void advwdt_disable(void) 97{ 98 inb_p(wdt_stop); 99} 100 101static 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 113static 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 135static 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 193static 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 205static int advwdt_close(struct inode *inode, struct file *file) 206{ 207 if (adv_expect_close == 42) { 208 advwdt_disable(); 209 } else { 210 printk(KERN_CRIT PFX 211 "Unexpected close, not stopping watchdog!\n"); 212 advwdt_ping(); 213 } 214 clear_bit(0, &advwdt_is_open); 215 adv_expect_close = 0; 216 return 0; 217} 218 219/* 220 * Kernel Interfaces 221 */ 222 223static const struct file_operations advwdt_fops = { 224 .owner = THIS_MODULE, 225 .llseek = no_llseek, 226 .write = advwdt_write, 227 .unlocked_ioctl = advwdt_ioctl, 228 .open = advwdt_open, 229 .release = advwdt_close, 230}; 231 232static struct miscdevice advwdt_miscdev = { 233 .minor = WATCHDOG_MINOR, 234 .name = "watchdog", 235 .fops = &advwdt_fops, 236}; 237 238/* 239 * Init & exit routines 240 */ 241 242static int __devinit advwdt_probe(struct platform_device *dev) 243{ 244 int ret; 245 246 if (wdt_stop != wdt_start) { 247 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { 248 printk(KERN_ERR PFX 249 "I/O address 0x%04x already in use\n", 250 wdt_stop); 251 ret = -EIO; 252 goto out; 253 } 254 } 255 256 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { 257 printk(KERN_ERR PFX 258 "I/O address 0x%04x already in use\n", 259 wdt_start); 260 ret = -EIO; 261 goto unreg_stop; 262 } 263 264 /* Check that the heartbeat value is within it's range ; 265 * if not reset to the default */ 266 if (advwdt_set_heartbeat(timeout)) { 267 advwdt_set_heartbeat(WATCHDOG_TIMEOUT); 268 printk(KERN_INFO PFX 269 "timeout value must be 1<=x<=63, using %d\n", timeout); 270 } 271 272 ret = misc_register(&advwdt_miscdev); 273 if (ret != 0) { 274 printk(KERN_ERR PFX 275 "cannot register miscdev on minor=%d (err=%d)\n", 276 WATCHDOG_MINOR, ret); 277 goto unreg_regions; 278 } 279 printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n", 280 timeout, nowayout); 281out: 282 return ret; 283unreg_regions: 284 release_region(wdt_start, 1); 285unreg_stop: 286 if (wdt_stop != wdt_start) 287 release_region(wdt_stop, 1); 288 goto out; 289} 290 291static int __devexit advwdt_remove(struct platform_device *dev) 292{ 293 misc_deregister(&advwdt_miscdev); 294 release_region(wdt_start, 1); 295 if (wdt_stop != wdt_start) 296 release_region(wdt_stop, 1); 297 298 return 0; 299} 300 301static void advwdt_shutdown(struct platform_device *dev) 302{ 303 /* Turn the WDT off if we have a soft shutdown */ 304 advwdt_disable(); 305} 306 307static struct platform_driver advwdt_driver = { 308 .probe = advwdt_probe, 309 .remove = __devexit_p(advwdt_remove), 310 .shutdown = advwdt_shutdown, 311 .driver = { 312 .owner = THIS_MODULE, 313 .name = DRV_NAME, 314 }, 315}; 316 317static int __init advwdt_init(void) 318{ 319 int err; 320 321 printk(KERN_INFO 322 "WDT driver for Advantech single board computer initialising.\n"); 323 324 err = platform_driver_register(&advwdt_driver); 325 if (err) 326 return err; 327 328 advwdt_platform_device = platform_device_register_simple(DRV_NAME, 329 -1, NULL, 0); 330 if (IS_ERR(advwdt_platform_device)) { 331 err = PTR_ERR(advwdt_platform_device); 332 goto unreg_platform_driver; 333 } 334 335 return 0; 336 337unreg_platform_driver: 338 platform_driver_unregister(&advwdt_driver); 339 return err; 340} 341 342static void __exit advwdt_exit(void) 343{ 344 platform_device_unregister(advwdt_platform_device); 345 platform_driver_unregister(&advwdt_driver); 346 printk(KERN_INFO PFX "Watchdog Module Unloaded.\n"); 347} 348 349module_init(advwdt_init); 350module_exit(advwdt_exit); 351 352MODULE_LICENSE("GPL"); 353MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>"); 354MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver"); 355MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 356