1 /* 2 * MachZ ZF-Logic Watchdog Timer driver for Linux 3 * 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License 7 * as published by the Free Software Foundation; either version 8 * 2 of the License, or (at your option) any later version. 9 * 10 * The author does NOT admit liability nor provide warranty for 11 * any of this software. This material is provided "AS-IS" in 12 * the hope that it may be useful for others. 13 * 14 * Author: Fernando Fuganti <fuganti@conectiva.com.br> 15 * 16 * Based on sbc60xxwdt.c by Jakob Oestergaard 17 * 18 * 19 * We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the 20 * following periods: 21 * wd#1 - 2 seconds; 22 * wd#2 - 7.2 ms; 23 * After the expiration of wd#1, it can generate a NMI, SCI, SMI, or 24 * a system RESET and it starts wd#2 that unconditionaly will RESET 25 * the system when the counter reaches zero. 26 * 27 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> 28 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT 29 */ 30 31 #include <linux/module.h> 32 #include <linux/moduleparam.h> 33 #include <linux/types.h> 34 #include <linux/timer.h> 35 #include <linux/jiffies.h> 36 #include <linux/miscdevice.h> 37 #include <linux/watchdog.h> 38 #include <linux/fs.h> 39 #include <linux/ioport.h> 40 #include <linux/notifier.h> 41 #include <linux/reboot.h> 42 #include <linux/init.h> 43 44 #include <asm/io.h> 45 #include <asm/uaccess.h> 46 #include <asm/system.h> 47 48 /* ports */ 49 #define ZF_IOBASE 0x218 50 #define INDEX 0x218 51 #define DATA_B 0x219 52 #define DATA_W 0x21A 53 #define DATA_D 0x21A 54 55 /* indexes */ /* size */ 56 #define ZFL_VERSION 0x02 /* 16 */ 57 #define CONTROL 0x10 /* 16 */ 58 #define STATUS 0x12 /* 8 */ 59 #define COUNTER_1 0x0C /* 16 */ 60 #define COUNTER_2 0x0E /* 8 */ 61 #define PULSE_LEN 0x0F /* 8 */ 62 63 /* controls */ 64 #define ENABLE_WD1 0x0001 65 #define ENABLE_WD2 0x0002 66 #define RESET_WD1 0x0010 67 #define RESET_WD2 0x0020 68 #define GEN_SCI 0x0100 69 #define GEN_NMI 0x0200 70 #define GEN_SMI 0x0400 71 #define GEN_RESET 0x0800 72 73 74 /* utilities */ 75 76 #define WD1 0 77 #define WD2 1 78 79 #define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); } 80 #define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); } 81 #define zf_get_ZFL_version() zf_readw(ZFL_VERSION) 82 83 84 static unsigned short zf_readw(unsigned char port) 85 { 86 outb(port, INDEX); 87 return inw(DATA_W); 88 } 89 90 91 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>"); 92 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver"); 93 MODULE_LICENSE("GPL"); 94 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 95 96 static int nowayout = WATCHDOG_NOWAYOUT; 97 module_param(nowayout, int, 0); 98 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 99 100 #define PFX "machzwd" 101 102 static struct watchdog_info zf_info = { 103 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 104 .firmware_version = 1, 105 .identity = "ZF-Logic watchdog", 106 }; 107 108 109 /* 110 * action refers to action taken when watchdog resets 111 * 0 = GEN_RESET 112 * 1 = GEN_SMI 113 * 2 = GEN_NMI 114 * 3 = GEN_SCI 115 * defaults to GEN_RESET (0) 116 */ 117 static int action = 0; 118 module_param(action, int, 0); 119 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI"); 120 121 static void zf_ping(unsigned long data); 122 123 static int zf_action = GEN_RESET; 124 static unsigned long zf_is_open; 125 static char zf_expect_close; 126 static spinlock_t zf_lock; 127 static spinlock_t zf_port_lock; 128 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0); 129 static unsigned long next_heartbeat = 0; 130 131 132 /* timeout for user land heart beat (10 seconds) */ 133 #define ZF_USER_TIMEO (HZ*10) 134 135 /* timeout for hardware watchdog (~500ms) */ 136 #define ZF_HW_TIMEO (HZ/2) 137 138 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */ 139 #define ZF_CTIMEOUT 0xffff 140 141 #ifndef ZF_DEBUG 142 # define dprintk(format, args...) 143 #else 144 # define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args) 145 #endif 146 147 148 static inline void zf_set_status(unsigned char new) 149 { 150 zf_writeb(STATUS, new); 151 } 152 153 154 /* CONTROL register functions */ 155 156 static inline unsigned short zf_get_control(void) 157 { 158 return zf_readw(CONTROL); 159 } 160 161 static inline void zf_set_control(unsigned short new) 162 { 163 zf_writew(CONTROL, new); 164 } 165 166 167 /* WD#? counter functions */ 168 /* 169 * Just set counter value 170 */ 171 172 static inline void zf_set_timer(unsigned short new, unsigned char n) 173 { 174 switch(n){ 175 case WD1: 176 zf_writew(COUNTER_1, new); 177 case WD2: 178 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new); 179 default: 180 return; 181 } 182 } 183 184 /* 185 * stop hardware timer 186 */ 187 static void zf_timer_off(void) 188 { 189 unsigned int ctrl_reg = 0; 190 unsigned long flags; 191 192 /* stop internal ping */ 193 del_timer_sync(&zf_timer); 194 195 spin_lock_irqsave(&zf_port_lock, flags); 196 /* stop watchdog timer */ 197 ctrl_reg = zf_get_control(); 198 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */ 199 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2); 200 zf_set_control(ctrl_reg); 201 spin_unlock_irqrestore(&zf_port_lock, flags); 202 203 printk(KERN_INFO PFX ": Watchdog timer is now disabled\n"); 204 } 205 206 207 /* 208 * start hardware timer 209 */ 210 static void zf_timer_on(void) 211 { 212 unsigned int ctrl_reg = 0; 213 unsigned long flags; 214 215 spin_lock_irqsave(&zf_port_lock, flags); 216 217 zf_writeb(PULSE_LEN, 0xff); 218 219 zf_set_timer(ZF_CTIMEOUT, WD1); 220 221 /* user land ping */ 222 next_heartbeat = jiffies + ZF_USER_TIMEO; 223 224 /* start the timer for internal ping */ 225 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); 226 227 /* start watchdog timer */ 228 ctrl_reg = zf_get_control(); 229 ctrl_reg |= (ENABLE_WD1|zf_action); 230 zf_set_control(ctrl_reg); 231 spin_unlock_irqrestore(&zf_port_lock, flags); 232 233 printk(KERN_INFO PFX ": Watchdog timer is now enabled\n"); 234 } 235 236 237 static void zf_ping(unsigned long data) 238 { 239 unsigned int ctrl_reg = 0; 240 unsigned long flags; 241 242 zf_writeb(COUNTER_2, 0xff); 243 244 if(time_before(jiffies, next_heartbeat)){ 245 246 dprintk("time_before: %ld\n", next_heartbeat - jiffies); 247 248 /* 249 * reset event is activated by transition from 0 to 1 on 250 * RESET_WD1 bit and we assume that it is already zero... 251 */ 252 253 spin_lock_irqsave(&zf_port_lock, flags); 254 ctrl_reg = zf_get_control(); 255 ctrl_reg |= RESET_WD1; 256 zf_set_control(ctrl_reg); 257 258 /* ...and nothing changes until here */ 259 ctrl_reg &= ~(RESET_WD1); 260 zf_set_control(ctrl_reg); 261 spin_unlock_irqrestore(&zf_port_lock, flags); 262 263 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); 264 }else{ 265 printk(KERN_CRIT PFX ": I will reset your machine\n"); 266 } 267 } 268 269 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count, 270 loff_t *ppos) 271 { 272 /* See if we got the magic character */ 273 if(count){ 274 275 /* 276 * no need to check for close confirmation 277 * no way to disable watchdog ;) 278 */ 279 if (!nowayout) { 280 size_t ofs; 281 282 /* 283 * note: just in case someone wrote the magic character 284 * five months ago... 285 */ 286 zf_expect_close = 0; 287 288 /* now scan */ 289 for (ofs = 0; ofs != count; ofs++){ 290 char c; 291 if (get_user(c, buf + ofs)) 292 return -EFAULT; 293 if (c == 'V'){ 294 zf_expect_close = 42; 295 dprintk("zf_expect_close = 42\n"); 296 } 297 } 298 } 299 300 /* 301 * Well, anyhow someone wrote to us, 302 * we should return that favour 303 */ 304 next_heartbeat = jiffies + ZF_USER_TIMEO; 305 dprintk("user ping at %ld\n", jiffies); 306 307 } 308 309 return count; 310 } 311 312 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd, 313 unsigned long arg) 314 { 315 void __user *argp = (void __user *)arg; 316 int __user *p = argp; 317 switch (cmd) { 318 case WDIOC_GETSUPPORT: 319 if (copy_to_user(argp, &zf_info, sizeof(zf_info))) 320 return -EFAULT; 321 break; 322 323 case WDIOC_GETSTATUS: 324 case WDIOC_GETBOOTSTATUS: 325 return put_user(0, p); 326 327 case WDIOC_KEEPALIVE: 328 zf_ping(0); 329 break; 330 331 default: 332 return -ENOTTY; 333 } 334 335 return 0; 336 } 337 338 static int zf_open(struct inode *inode, struct file *file) 339 { 340 spin_lock(&zf_lock); 341 if(test_and_set_bit(0, &zf_is_open)) { 342 spin_unlock(&zf_lock); 343 return -EBUSY; 344 } 345 346 if (nowayout) 347 __module_get(THIS_MODULE); 348 349 spin_unlock(&zf_lock); 350 351 zf_timer_on(); 352 353 return nonseekable_open(inode, file); 354 } 355 356 static int zf_close(struct inode *inode, struct file *file) 357 { 358 if(zf_expect_close == 42){ 359 zf_timer_off(); 360 } else { 361 del_timer(&zf_timer); 362 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n"); 363 } 364 365 spin_lock(&zf_lock); 366 clear_bit(0, &zf_is_open); 367 spin_unlock(&zf_lock); 368 369 zf_expect_close = 0; 370 371 return 0; 372 } 373 374 /* 375 * Notifier for system down 376 */ 377 378 static int zf_notify_sys(struct notifier_block *this, unsigned long code, 379 void *unused) 380 { 381 if(code == SYS_DOWN || code == SYS_HALT){ 382 zf_timer_off(); 383 } 384 385 return NOTIFY_DONE; 386 } 387 388 389 390 391 static const struct file_operations zf_fops = { 392 .owner = THIS_MODULE, 393 .llseek = no_llseek, 394 .write = zf_write, 395 .ioctl = zf_ioctl, 396 .open = zf_open, 397 .release = zf_close, 398 }; 399 400 static struct miscdevice zf_miscdev = { 401 .minor = WATCHDOG_MINOR, 402 .name = "watchdog", 403 .fops = &zf_fops, 404 }; 405 406 407 /* 408 * The device needs to learn about soft shutdowns in order to 409 * turn the timebomb registers off. 410 */ 411 static struct notifier_block zf_notifier = { 412 .notifier_call = zf_notify_sys, 413 }; 414 415 static void __init zf_show_action(int act) 416 { 417 char *str[] = { "RESET", "SMI", "NMI", "SCI" }; 418 419 printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]); 420 } 421 422 static int __init zf_init(void) 423 { 424 int ret; 425 426 printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n"); 427 428 ret = zf_get_ZFL_version(); 429 if ((!ret) || (ret == 0xffff)) { 430 printk(KERN_WARNING PFX ": no ZF-Logic found\n"); 431 return -ENODEV; 432 } 433 434 if((action <= 3) && (action >= 0)){ 435 zf_action = zf_action>>action; 436 } else 437 action = 0; 438 439 zf_show_action(action); 440 441 spin_lock_init(&zf_lock); 442 spin_lock_init(&zf_port_lock); 443 444 if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){ 445 printk(KERN_ERR "cannot reserve I/O ports at %d\n", 446 ZF_IOBASE); 447 ret = -EBUSY; 448 goto no_region; 449 } 450 451 ret = register_reboot_notifier(&zf_notifier); 452 if(ret){ 453 printk(KERN_ERR "can't register reboot notifier (err=%d)\n", 454 ret); 455 goto no_reboot; 456 } 457 458 ret = misc_register(&zf_miscdev); 459 if (ret){ 460 printk(KERN_ERR "can't misc_register on minor=%d\n", 461 WATCHDOG_MINOR); 462 goto no_misc; 463 } 464 465 zf_set_status(0); 466 zf_set_control(0); 467 468 return 0; 469 470 no_misc: 471 unregister_reboot_notifier(&zf_notifier); 472 no_reboot: 473 release_region(ZF_IOBASE, 3); 474 no_region: 475 return ret; 476 } 477 478 479 static void __exit zf_exit(void) 480 { 481 zf_timer_off(); 482 483 misc_deregister(&zf_miscdev); 484 unregister_reboot_notifier(&zf_notifier); 485 release_region(ZF_IOBASE, 3); 486 } 487 488 module_init(zf_init); 489 module_exit(zf_exit); 490