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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 | /* * Acquire Single Board Computer Watchdog Timer driver * * Based on wdt.c. Original copyright messages: * * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. * http://www.redhat.com * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide * warranty for any of this software. This material is provided * "AS-IS" and at no charge. * * (c) Copyright 1995 Alan Cox <alan@redhat.com> * * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT * Can't add timeout - driver doesn't allow changing value */ /* * Theory of Operation: * The Watch-Dog Timer is provided to ensure that standalone * Systems can always recover from catastrophic conditions that * caused the CPU to crash. This condition may have occured by * external EMI or a software bug. When the CPU stops working * correctly, hardware on the board will either perform a hardware * reset (cold boot) or a non-maskable interrupt (NMI) to bring the * system back to a known state. * * The Watch-Dog Timer is controlled by two I/O Ports. * 443 hex - Read - Enable or refresh the Watch-Dog Timer * 043 hex - Read - Disable the Watch-Dog Timer * * To enable the Watch-Dog Timer, a read from I/O port 443h must * be performed. This will enable and activate the countdown timer * which will eventually time out and either reset the CPU or cause * an NMI depending on the setting of a jumper. To ensure that this * reset condition does not occur, the Watch-Dog Timer must be * periodically refreshed by reading the same I/O port 443h. * The Watch-Dog Timer is disabled by reading I/O port 043h. * * The Watch-Dog Timer Time-Out Period is set via jumpers. * It can be 1, 2, 10, 20, 110 or 220 seconds. */ /* * Includes, defines, variables, module parameters, ... */ /* Includes */ #include <linux/module.h> /* For module specific items */ #include <linux/moduleparam.h> /* For new moduleparam's */ #include <linux/types.h> /* For standard types (like size_t) */ #include <linux/errno.h> /* For the -ENODEV/... values */ #include <linux/kernel.h> /* For printk/panic/... */ #include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) */ #include <linux/watchdog.h> /* For the watchdog specific items */ #include <linux/fs.h> /* For file operations */ #include <linux/ioport.h> /* For io-port access */ #include <linux/platform_device.h> /* For platform_driver framework */ #include <linux/init.h> /* For __init/__exit/... */ #include <asm/uaccess.h> /* For copy_to_user/put_user/... */ #include <asm/io.h> /* For inb/outb/... */ /* Module information */ #define DRV_NAME "acquirewdt" #define PFX DRV_NAME ": " #define WATCHDOG_NAME "Acquire WDT" #define WATCHDOG_HEARTBEAT 0 /* There is no way to see what the correct time-out period is */ /* internal variables */ static struct platform_device *acq_platform_device; /* the watchdog platform device */ static unsigned long acq_is_open; static char expect_close; /* module parameters */ static int wdt_stop = 0x43; /* You must set this - there is no sane way to probe for this board. */ module_param(wdt_stop, int, 0); MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)"); static int wdt_start = 0x443; /* You must set this - there is no sane way to probe for this board. */ module_param(wdt_start, int, 0); MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)"); static int nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); /* * Watchdog Operations */ static void acq_keepalive(void) { /* Write a watchdog value */ inb_p(wdt_start); } static void acq_stop(void) { /* Turn the card off */ inb_p(wdt_stop); } /* * /dev/watchdog handling */ static ssize_t acq_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { /* See if we got the magic character 'V' and reload the timer */ if(count) { if (!nowayout) { size_t i; /* note: just in case someone wrote the magic character * five months ago... */ expect_close = 0; /* scan to see whether or not we got the magic character */ for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } /* Well, anyhow someone wrote to us, we should return that favour */ acq_keepalive(); } return count; } static int acq_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int options, retval = -EINVAL; void __user *argp = (void __user *)arg; int __user *p = argp; static struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = WATCHDOG_NAME, }; switch(cmd) { case WDIOC_GETSUPPORT: return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_KEEPALIVE: acq_keepalive(); return 0; case WDIOC_GETTIMEOUT: return put_user(WATCHDOG_HEARTBEAT, p); case WDIOC_SETOPTIONS: { if (get_user(options, p)) return -EFAULT; if (options & WDIOS_DISABLECARD) { acq_stop(); retval = 0; } if (options & WDIOS_ENABLECARD) { acq_keepalive(); retval = 0; } return retval; } default: return -ENOTTY; } } static int acq_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &acq_is_open)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); /* Activate */ acq_keepalive(); return nonseekable_open(inode, file); } static int acq_close(struct inode *inode, struct file *file) { if (expect_close == 42) { acq_stop(); } else { printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); acq_keepalive(); } clear_bit(0, &acq_is_open); expect_close = 0; return 0; } /* * Kernel Interfaces */ static const struct file_operations acq_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = acq_write, .ioctl = acq_ioctl, .open = acq_open, .release = acq_close, }; static struct miscdevice acq_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &acq_fops, }; /* * Init & exit routines */ static int __devinit acq_probe(struct platform_device *dev) { int ret; if (wdt_stop != wdt_start) { if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", wdt_stop); ret = -EIO; goto out; } } if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", wdt_start); ret = -EIO; goto unreg_stop; } ret = misc_register(&acq_miscdev); if (ret != 0) { printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); goto unreg_regions; } printk (KERN_INFO PFX "initialized. (nowayout=%d)\n", nowayout); return 0; unreg_regions: release_region(wdt_start, 1); unreg_stop: if (wdt_stop != wdt_start) release_region(wdt_stop, 1); out: return ret; } static int __devexit acq_remove(struct platform_device *dev) { misc_deregister(&acq_miscdev); release_region(wdt_start,1); if(wdt_stop != wdt_start) release_region(wdt_stop,1); return 0; } static void acq_shutdown(struct platform_device *dev) { /* Turn the WDT off if we have a soft shutdown */ acq_stop(); } static struct platform_driver acquirewdt_driver = { .probe = acq_probe, .remove = __devexit_p(acq_remove), .shutdown = acq_shutdown, .driver = { .owner = THIS_MODULE, .name = DRV_NAME, }, }; static int __init acq_init(void) { int err; printk(KERN_INFO "WDT driver for Acquire single board computer initialising.\n"); err = platform_driver_register(&acquirewdt_driver); if (err) return err; acq_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0); if (IS_ERR(acq_platform_device)) { err = PTR_ERR(acq_platform_device); goto unreg_platform_driver; } return 0; unreg_platform_driver: platform_driver_unregister(&acquirewdt_driver); return err; } static void __exit acq_exit(void) { platform_device_unregister(acq_platform_device); platform_driver_unregister(&acquirewdt_driver); printk(KERN_INFO PFX "Watchdog Module Unloaded.\n"); } module_init(acq_init); module_exit(acq_exit); MODULE_AUTHOR("David Woodhouse"); MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |