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 unconditionally 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 #include <linux/io.h> 44 #include <linux/uaccess.h> 45 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, 99 "Watchdog cannot be stopped once started (default=" 100 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 101 102 #define PFX "machzwd" 103 104 static const struct watchdog_info zf_info = { 105 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 106 .firmware_version = 1, 107 .identity = "ZF-Logic watchdog", 108 }; 109 110 111 /* 112 * action refers to action taken when watchdog resets 113 * 0 = GEN_RESET 114 * 1 = GEN_SMI 115 * 2 = GEN_NMI 116 * 3 = GEN_SCI 117 * defaults to GEN_RESET (0) 118 */ 119 static int action; 120 module_param(action, int, 0); 121 MODULE_PARM_DESC(action, "after watchdog resets, generate: " 122 "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI"); 123 124 static void zf_ping(unsigned long data); 125 126 static int zf_action = GEN_RESET; 127 static unsigned long zf_is_open; 128 static char zf_expect_close; 129 static DEFINE_SPINLOCK(zf_port_lock); 130 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0); 131 static unsigned long next_heartbeat; 132 133 134 /* timeout for user land heart beat (10 seconds) */ 135 #define ZF_USER_TIMEO (HZ*10) 136 137 /* timeout for hardware watchdog (~500ms) */ 138 #define ZF_HW_TIMEO (HZ/2) 139 140 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */ 141 #define ZF_CTIMEOUT 0xffff 142 143 #ifndef ZF_DEBUG 144 # define dprintk(format, args...) 145 #else 146 # define dprintk(format, args...) printk(KERN_DEBUG PFX 147 ":%s:%d: " format, __func__, __LINE__ , ## args) 148 #endif 149 150 151 static inline void zf_set_status(unsigned char new) 152 { 153 zf_writeb(STATUS, new); 154 } 155 156 157 /* CONTROL register functions */ 158 159 static inline unsigned short zf_get_control(void) 160 { 161 return zf_readw(CONTROL); 162 } 163 164 static inline void zf_set_control(unsigned short new) 165 { 166 zf_writew(CONTROL, new); 167 } 168 169 170 /* WD#? counter functions */ 171 /* 172 * Just set counter value 173 */ 174 175 static inline void zf_set_timer(unsigned short new, unsigned char n) 176 { 177 switch (n) { 178 case WD1: 179 zf_writew(COUNTER_1, new); 180 case WD2: 181 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new); 182 default: 183 return; 184 } 185 } 186 187 /* 188 * stop hardware timer 189 */ 190 static void zf_timer_off(void) 191 { 192 unsigned int ctrl_reg = 0; 193 unsigned long flags; 194 195 /* stop internal ping */ 196 del_timer_sync(&zf_timer); 197 198 spin_lock_irqsave(&zf_port_lock, flags); 199 /* stop watchdog timer */ 200 ctrl_reg = zf_get_control(); 201 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */ 202 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2); 203 zf_set_control(ctrl_reg); 204 spin_unlock_irqrestore(&zf_port_lock, flags); 205 206 printk(KERN_INFO PFX ": Watchdog timer is now disabled\n"); 207 } 208 209 210 /* 211 * start hardware timer 212 */ 213 static void zf_timer_on(void) 214 { 215 unsigned int ctrl_reg = 0; 216 unsigned long flags; 217 218 spin_lock_irqsave(&zf_port_lock, flags); 219 220 zf_writeb(PULSE_LEN, 0xff); 221 222 zf_set_timer(ZF_CTIMEOUT, WD1); 223 224 /* user land ping */ 225 next_heartbeat = jiffies + ZF_USER_TIMEO; 226 227 /* start the timer for internal ping */ 228 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); 229 230 /* start watchdog timer */ 231 ctrl_reg = zf_get_control(); 232 ctrl_reg |= (ENABLE_WD1|zf_action); 233 zf_set_control(ctrl_reg); 234 spin_unlock_irqrestore(&zf_port_lock, flags); 235 236 printk(KERN_INFO PFX ": Watchdog timer is now enabled\n"); 237 } 238 239 240 static void zf_ping(unsigned long data) 241 { 242 unsigned int ctrl_reg = 0; 243 unsigned long flags; 244 245 zf_writeb(COUNTER_2, 0xff); 246 247 if (time_before(jiffies, next_heartbeat)) { 248 dprintk("time_before: %ld\n", next_heartbeat - jiffies); 249 /* 250 * reset event is activated by transition from 0 to 1 on 251 * RESET_WD1 bit and we assume that it is already zero... 252 */ 253 254 spin_lock_irqsave(&zf_port_lock, flags); 255 ctrl_reg = zf_get_control(); 256 ctrl_reg |= RESET_WD1; 257 zf_set_control(ctrl_reg); 258 259 /* ...and nothing changes until here */ 260 ctrl_reg &= ~(RESET_WD1); 261 zf_set_control(ctrl_reg); 262 spin_unlock_irqrestore(&zf_port_lock, flags); 263 264 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); 265 } else 266 printk(KERN_CRIT PFX ": I will reset your machine\n"); 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 * no need to check for close confirmation 276 * no way to disable watchdog ;) 277 */ 278 if (!nowayout) { 279 size_t ofs; 280 /* 281 * note: just in case someone wrote the magic character 282 * five months ago... 283 */ 284 zf_expect_close = 0; 285 286 /* now scan */ 287 for (ofs = 0; ofs != count; ofs++) { 288 char c; 289 if (get_user(c, buf + ofs)) 290 return -EFAULT; 291 if (c == 'V') { 292 zf_expect_close = 42; 293 dprintk("zf_expect_close = 42\n"); 294 } 295 } 296 } 297 298 /* 299 * Well, anyhow someone wrote to us, 300 * we should return that favour 301 */ 302 next_heartbeat = jiffies + ZF_USER_TIMEO; 303 dprintk("user ping at %ld\n", jiffies); 304 } 305 return count; 306 } 307 308 static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 309 { 310 void __user *argp = (void __user *)arg; 311 int __user *p = argp; 312 switch (cmd) { 313 case WDIOC_GETSUPPORT: 314 if (copy_to_user(argp, &zf_info, sizeof(zf_info))) 315 return -EFAULT; 316 break; 317 case WDIOC_GETSTATUS: 318 case WDIOC_GETBOOTSTATUS: 319 return put_user(0, p); 320 case WDIOC_KEEPALIVE: 321 zf_ping(0); 322 break; 323 default: 324 return -ENOTTY; 325 } 326 return 0; 327 } 328 329 static int zf_open(struct inode *inode, struct file *file) 330 { 331 if (test_and_set_bit(0, &zf_is_open)) 332 return -EBUSY; 333 if (nowayout) 334 __module_get(THIS_MODULE); 335 zf_timer_on(); 336 return nonseekable_open(inode, file); 337 } 338 339 static int zf_close(struct inode *inode, struct file *file) 340 { 341 if (zf_expect_close == 42) 342 zf_timer_off(); 343 else { 344 del_timer(&zf_timer); 345 printk(KERN_ERR PFX ": device file closed unexpectedly. " 346 "Will not stop the WDT!\n"); 347 } 348 clear_bit(0, &zf_is_open); 349 zf_expect_close = 0; 350 return 0; 351 } 352 353 /* 354 * Notifier for system down 355 */ 356 357 static int zf_notify_sys(struct notifier_block *this, unsigned long code, 358 void *unused) 359 { 360 if (code == SYS_DOWN || code == SYS_HALT) 361 zf_timer_off(); 362 return NOTIFY_DONE; 363 } 364 365 static const struct file_operations zf_fops = { 366 .owner = THIS_MODULE, 367 .llseek = no_llseek, 368 .write = zf_write, 369 .unlocked_ioctl = zf_ioctl, 370 .open = zf_open, 371 .release = zf_close, 372 }; 373 374 static struct miscdevice zf_miscdev = { 375 .minor = WATCHDOG_MINOR, 376 .name = "watchdog", 377 .fops = &zf_fops, 378 }; 379 380 381 /* 382 * The device needs to learn about soft shutdowns in order to 383 * turn the timebomb registers off. 384 */ 385 static struct notifier_block zf_notifier = { 386 .notifier_call = zf_notify_sys, 387 }; 388 389 static void __init zf_show_action(int act) 390 { 391 char *str[] = { "RESET", "SMI", "NMI", "SCI" }; 392 393 printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]); 394 } 395 396 static int __init zf_init(void) 397 { 398 int ret; 399 400 printk(KERN_INFO PFX 401 ": MachZ ZF-Logic Watchdog driver initializing.\n"); 402 403 ret = zf_get_ZFL_version(); 404 if (!ret || ret == 0xffff) { 405 printk(KERN_WARNING PFX ": no ZF-Logic found\n"); 406 return -ENODEV; 407 } 408 409 if (action <= 3 && action >= 0) 410 zf_action = zf_action >> action; 411 else 412 action = 0; 413 414 zf_show_action(action); 415 416 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) { 417 printk(KERN_ERR "cannot reserve I/O ports at %d\n", 418 ZF_IOBASE); 419 ret = -EBUSY; 420 goto no_region; 421 } 422 423 ret = register_reboot_notifier(&zf_notifier); 424 if (ret) { 425 printk(KERN_ERR "can't register reboot notifier (err=%d)\n", 426 ret); 427 goto no_reboot; 428 } 429 430 ret = misc_register(&zf_miscdev); 431 if (ret) { 432 printk(KERN_ERR "can't misc_register on minor=%d\n", 433 WATCHDOG_MINOR); 434 goto no_misc; 435 } 436 437 zf_set_status(0); 438 zf_set_control(0); 439 440 return 0; 441 442 no_misc: 443 unregister_reboot_notifier(&zf_notifier); 444 no_reboot: 445 release_region(ZF_IOBASE, 3); 446 no_region: 447 return ret; 448 } 449 450 451 static void __exit zf_exit(void) 452 { 453 zf_timer_off(); 454 455 misc_deregister(&zf_miscdev); 456 unregister_reboot_notifier(&zf_notifier); 457 release_region(ZF_IOBASE, 3); 458 } 459 460 module_init(zf_init); 461 module_exit(zf_exit); 462