1 /* 2 * i6300esb: Watchdog timer driver for Intel 6300ESB chipset 3 * 4 * (c) Copyright 2004 Google Inc. 5 * (c) Copyright 2005 David Härdeman <david@2gen.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * based on i810-tco.c which is in turn based on softdog.c 13 * 14 * The timer is implemented in the following I/O controller hubs: 15 * (See the intel documentation on http://developer.intel.com.) 16 * 6300ESB chip : document number 300641-003 17 * 18 * 2004YYZZ Ross Biro 19 * Initial version 0.01 20 * 2004YYZZ Ross Biro 21 * Version 0.02 22 * 20050210 David Härdeman <david@2gen.com> 23 * Ported driver to kernel 2.6 24 */ 25 26 /* 27 * Includes, defines, variables, module parameters, ... 28 */ 29 30 #include <linux/module.h> 31 #include <linux/types.h> 32 #include <linux/kernel.h> 33 #include <linux/fs.h> 34 #include <linux/mm.h> 35 #include <linux/miscdevice.h> 36 #include <linux/watchdog.h> 37 #include <linux/reboot.h> 38 #include <linux/init.h> 39 #include <linux/pci.h> 40 #include <linux/ioport.h> 41 42 #include <asm/uaccess.h> 43 #include <asm/io.h> 44 45 /* Module and version information */ 46 #define ESB_VERSION "0.03" 47 #define ESB_MODULE_NAME "i6300ESB timer" 48 #define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION 49 #define PFX ESB_MODULE_NAME ": " 50 51 /* PCI configuration registers */ 52 #define ESB_CONFIG_REG 0x60 /* Config register */ 53 #define ESB_LOCK_REG 0x68 /* WDT lock register */ 54 55 /* Memory mapped registers */ 56 #define ESB_TIMER1_REG BASEADDR + 0x00 /* Timer1 value after each reset */ 57 #define ESB_TIMER2_REG BASEADDR + 0x04 /* Timer2 value after each reset */ 58 #define ESB_GINTSR_REG BASEADDR + 0x08 /* General Interrupt Status Register */ 59 #define ESB_RELOAD_REG BASEADDR + 0x0c /* Reload register */ 60 61 /* Lock register bits */ 62 #define ESB_WDT_FUNC ( 0x01 << 2 ) /* Watchdog functionality */ 63 #define ESB_WDT_ENABLE ( 0x01 << 1 ) /* Enable WDT */ 64 #define ESB_WDT_LOCK ( 0x01 << 0 ) /* Lock (nowayout) */ 65 66 /* Config register bits */ 67 #define ESB_WDT_REBOOT ( 0x01 << 5 ) /* Enable reboot on timeout */ 68 #define ESB_WDT_FREQ ( 0x01 << 2 ) /* Decrement frequency */ 69 #define ESB_WDT_INTTYPE ( 0x11 << 0 ) /* Interrupt type on timer1 timeout */ 70 71 /* Reload register bits */ 72 #define ESB_WDT_RELOAD ( 0x01 << 8 ) /* prevent timeout */ 73 74 /* Magic constants */ 75 #define ESB_UNLOCK1 0x80 /* Step 1 to unlock reset registers */ 76 #define ESB_UNLOCK2 0x86 /* Step 2 to unlock reset registers */ 77 78 /* internal variables */ 79 static void __iomem *BASEADDR; 80 static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */ 81 static unsigned long timer_alive; 82 static struct pci_dev *esb_pci; 83 static unsigned short triggered; /* The status of the watchdog upon boot */ 84 static char esb_expect_close; 85 86 /* module parameters */ 87 #define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (1<heartbeat<2*1023) */ 88 static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */ 89 module_param(heartbeat, int, 0); 90 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (1<heartbeat<2046, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")"); 91 92 static int nowayout = WATCHDOG_NOWAYOUT; 93 module_param(nowayout, int, 0); 94 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 95 96 /* 97 * Some i6300ESB specific functions 98 */ 99 100 /* 101 * Prepare for reloading the timer by unlocking the proper registers. 102 * This is performed by first writing 0x80 followed by 0x86 to the 103 * reload register. After this the appropriate registers can be written 104 * to once before they need to be unlocked again. 105 */ 106 static inline void esb_unlock_registers(void) { 107 writeb(ESB_UNLOCK1, ESB_RELOAD_REG); 108 writeb(ESB_UNLOCK2, ESB_RELOAD_REG); 109 } 110 111 static void esb_timer_start(void) 112 { 113 u8 val; 114 115 /* Enable or Enable + Lock? */ 116 val = 0x02 | (nowayout ? 0x01 : 0x00); 117 118 pci_write_config_byte(esb_pci, ESB_LOCK_REG, val); 119 } 120 121 static int esb_timer_stop(void) 122 { 123 u8 val; 124 125 spin_lock(&esb_lock); 126 /* First, reset timers as suggested by the docs */ 127 esb_unlock_registers(); 128 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG); 129 /* Then disable the WDT */ 130 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0); 131 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val); 132 spin_unlock(&esb_lock); 133 134 /* Returns 0 if the timer was disabled, non-zero otherwise */ 135 return (val & 0x01); 136 } 137 138 static void esb_timer_keepalive(void) 139 { 140 spin_lock(&esb_lock); 141 esb_unlock_registers(); 142 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG); 143 /* FIXME: Do we need to flush anything here? */ 144 spin_unlock(&esb_lock); 145 } 146 147 static int esb_timer_set_heartbeat(int time) 148 { 149 u32 val; 150 151 if (time < 0x1 || time > (2 * 0x03ff)) 152 return -EINVAL; 153 154 spin_lock(&esb_lock); 155 156 /* We shift by 9, so if we are passed a value of 1 sec, 157 * val will be 1 << 9 = 512, then write that to two 158 * timers => 2 * 512 = 1024 (which is decremented at 1KHz) 159 */ 160 val = time << 9; 161 162 /* Write timer 1 */ 163 esb_unlock_registers(); 164 writel(val, ESB_TIMER1_REG); 165 166 /* Write timer 2 */ 167 esb_unlock_registers(); 168 writel(val, ESB_TIMER2_REG); 169 170 /* Reload */ 171 esb_unlock_registers(); 172 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG); 173 174 /* FIXME: Do we need to flush everything out? */ 175 176 /* Done */ 177 heartbeat = time; 178 spin_unlock(&esb_lock); 179 return 0; 180 } 181 182 static int esb_timer_read (void) 183 { 184 u32 count; 185 186 /* This isn't documented, and doesn't take into 187 * acount which stage is running, but it looks 188 * like a 20 bit count down, so we might as well report it. 189 */ 190 pci_read_config_dword(esb_pci, 0x64, &count); 191 return (int)count; 192 } 193 194 /* 195 * /dev/watchdog handling 196 */ 197 198 static int esb_open (struct inode *inode, struct file *file) 199 { 200 /* /dev/watchdog can only be opened once */ 201 if (test_and_set_bit(0, &timer_alive)) 202 return -EBUSY; 203 204 /* Reload and activate timer */ 205 esb_timer_keepalive (); 206 esb_timer_start (); 207 208 return nonseekable_open(inode, file); 209 } 210 211 static int esb_release (struct inode *inode, struct file *file) 212 { 213 /* Shut off the timer. */ 214 if (esb_expect_close == 42) { 215 esb_timer_stop (); 216 } else { 217 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); 218 esb_timer_keepalive (); 219 } 220 clear_bit(0, &timer_alive); 221 esb_expect_close = 0; 222 return 0; 223 } 224 225 static ssize_t esb_write (struct file *file, const char __user *data, 226 size_t len, loff_t * ppos) 227 { 228 /* See if we got the magic character 'V' and reload the timer */ 229 if (len) { 230 if (!nowayout) { 231 size_t i; 232 233 /* note: just in case someone wrote the magic character 234 * five months ago... */ 235 esb_expect_close = 0; 236 237 /* scan to see whether or not we got the magic character */ 238 for (i = 0; i != len; i++) { 239 char c; 240 if(get_user(c, data+i)) 241 return -EFAULT; 242 if (c == 'V') 243 esb_expect_close = 42; 244 } 245 } 246 247 /* someone wrote to us, we should reload the timer */ 248 esb_timer_keepalive (); 249 } 250 return len; 251 } 252 253 static int esb_ioctl (struct inode *inode, struct file *file, 254 unsigned int cmd, unsigned long arg) 255 { 256 int new_options, retval = -EINVAL; 257 int new_heartbeat; 258 void __user *argp = (void __user *)arg; 259 int __user *p = argp; 260 static struct watchdog_info ident = { 261 .options = WDIOF_SETTIMEOUT | 262 WDIOF_KEEPALIVEPING | 263 WDIOF_MAGICCLOSE, 264 .firmware_version = 0, 265 .identity = ESB_MODULE_NAME, 266 }; 267 268 switch (cmd) { 269 case WDIOC_GETSUPPORT: 270 return copy_to_user(argp, &ident, 271 sizeof (ident)) ? -EFAULT : 0; 272 273 case WDIOC_GETSTATUS: 274 return put_user (esb_timer_read(), p); 275 276 case WDIOC_GETBOOTSTATUS: 277 return put_user (triggered, p); 278 279 case WDIOC_KEEPALIVE: 280 esb_timer_keepalive (); 281 return 0; 282 283 case WDIOC_SETOPTIONS: 284 { 285 if (get_user (new_options, p)) 286 return -EFAULT; 287 288 if (new_options & WDIOS_DISABLECARD) { 289 esb_timer_stop (); 290 retval = 0; 291 } 292 293 if (new_options & WDIOS_ENABLECARD) { 294 esb_timer_keepalive (); 295 esb_timer_start (); 296 retval = 0; 297 } 298 299 return retval; 300 } 301 302 case WDIOC_SETTIMEOUT: 303 { 304 if (get_user(new_heartbeat, p)) 305 return -EFAULT; 306 307 if (esb_timer_set_heartbeat(new_heartbeat)) 308 return -EINVAL; 309 310 esb_timer_keepalive (); 311 /* Fall */ 312 } 313 314 case WDIOC_GETTIMEOUT: 315 return put_user(heartbeat, p); 316 317 default: 318 return -ENOTTY; 319 } 320 } 321 322 /* 323 * Notify system 324 */ 325 326 static int esb_notify_sys (struct notifier_block *this, unsigned long code, void *unused) 327 { 328 if (code==SYS_DOWN || code==SYS_HALT) { 329 /* Turn the WDT off */ 330 esb_timer_stop (); 331 } 332 333 return NOTIFY_DONE; 334 } 335 336 /* 337 * Kernel Interfaces 338 */ 339 340 static const struct file_operations esb_fops = { 341 .owner = THIS_MODULE, 342 .llseek = no_llseek, 343 .write = esb_write, 344 .ioctl = esb_ioctl, 345 .open = esb_open, 346 .release = esb_release, 347 }; 348 349 static struct miscdevice esb_miscdev = { 350 .minor = WATCHDOG_MINOR, 351 .name = "watchdog", 352 .fops = &esb_fops, 353 }; 354 355 static struct notifier_block esb_notifier = { 356 .notifier_call = esb_notify_sys, 357 }; 358 359 /* 360 * Data for PCI driver interface 361 * 362 * This data only exists for exporting the supported 363 * PCI ids via MODULE_DEVICE_TABLE. We do not actually 364 * register a pci_driver, because someone else might one day 365 * want to register another driver on the same PCI id. 366 */ 367 static struct pci_device_id esb_pci_tbl[] = { 368 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), }, 369 { 0, }, /* End of list */ 370 }; 371 MODULE_DEVICE_TABLE (pci, esb_pci_tbl); 372 373 /* 374 * Init & exit routines 375 */ 376 377 static unsigned char __init esb_getdevice (void) 378 { 379 u8 val1; 380 unsigned short val2; 381 382 struct pci_dev *dev = NULL; 383 /* 384 * Find the PCI device 385 */ 386 387 for_each_pci_dev(dev) { 388 if (pci_match_id(esb_pci_tbl, dev)) { 389 esb_pci = dev; 390 break; 391 } 392 } 393 394 if (esb_pci) { 395 if (pci_enable_device(esb_pci)) { 396 printk (KERN_ERR PFX "failed to enable device\n"); 397 goto err_devput; 398 } 399 400 if (pci_request_region(esb_pci, 0, ESB_MODULE_NAME)) { 401 printk (KERN_ERR PFX "failed to request region\n"); 402 goto err_disable; 403 } 404 405 BASEADDR = ioremap(pci_resource_start(esb_pci, 0), 406 pci_resource_len(esb_pci, 0)); 407 if (BASEADDR == NULL) { 408 /* Something's wrong here, BASEADDR has to be set */ 409 printk (KERN_ERR PFX "failed to get BASEADDR\n"); 410 goto err_release; 411 } 412 413 /* 414 * The watchdog has two timers, it can be setup so that the 415 * expiry of timer1 results in an interrupt and the expiry of 416 * timer2 results in a reboot. We set it to not generate 417 * any interrupts as there is not much we can do with it 418 * right now. 419 * 420 * We also enable reboots and set the timer frequency to 421 * the PCI clock divided by 2^15 (approx 1KHz). 422 */ 423 pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003); 424 425 /* Check that the WDT isn't already locked */ 426 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1); 427 if (val1 & ESB_WDT_LOCK) 428 printk (KERN_WARNING PFX "nowayout already set\n"); 429 430 /* Set the timer to watchdog mode and disable it for now */ 431 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00); 432 433 /* Check if the watchdog was previously triggered */ 434 esb_unlock_registers(); 435 val2 = readw(ESB_RELOAD_REG); 436 triggered = (val2 & (0x01 << 9) >> 9); 437 438 /* Reset trigger flag and timers */ 439 esb_unlock_registers(); 440 writew((0x11 << 8), ESB_RELOAD_REG); 441 442 /* Done */ 443 return 1; 444 445 err_release: 446 pci_release_region(esb_pci, 0); 447 err_disable: 448 pci_disable_device(esb_pci); 449 err_devput: 450 pci_dev_put(esb_pci); 451 } 452 return 0; 453 } 454 455 static int __init watchdog_init (void) 456 { 457 int ret; 458 459 /* Check whether or not the hardware watchdog is there */ 460 if (!esb_getdevice () || esb_pci == NULL) 461 return -ENODEV; 462 463 /* Check that the heartbeat value is within it's range ; if not reset to the default */ 464 if (esb_timer_set_heartbeat (heartbeat)) { 465 esb_timer_set_heartbeat (WATCHDOG_HEARTBEAT); 466 printk(KERN_INFO PFX "heartbeat value must be 1<heartbeat<2046, using %d\n", 467 heartbeat); 468 } 469 470 ret = register_reboot_notifier(&esb_notifier); 471 if (ret != 0) { 472 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", 473 ret); 474 goto err_unmap; 475 } 476 477 ret = misc_register(&esb_miscdev); 478 if (ret != 0) { 479 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", 480 WATCHDOG_MINOR, ret); 481 goto err_notifier; 482 } 483 484 esb_timer_stop (); 485 486 printk (KERN_INFO PFX "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n", 487 BASEADDR, heartbeat, nowayout); 488 489 return 0; 490 491 err_notifier: 492 unregister_reboot_notifier(&esb_notifier); 493 err_unmap: 494 iounmap(BASEADDR); 495 /* err_release: */ 496 pci_release_region(esb_pci, 0); 497 /* err_disable: */ 498 pci_disable_device(esb_pci); 499 /* err_devput: */ 500 pci_dev_put(esb_pci); 501 return ret; 502 } 503 504 static void __exit watchdog_cleanup (void) 505 { 506 /* Stop the timer before we leave */ 507 if (!nowayout) 508 esb_timer_stop (); 509 510 /* Deregister */ 511 misc_deregister(&esb_miscdev); 512 unregister_reboot_notifier(&esb_notifier); 513 iounmap(BASEADDR); 514 pci_release_region(esb_pci, 0); 515 pci_disable_device(esb_pci); 516 pci_dev_put(esb_pci); 517 } 518 519 module_init(watchdog_init); 520 module_exit(watchdog_cleanup); 521 522 MODULE_AUTHOR("Ross Biro and David Härdeman"); 523 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets"); 524 MODULE_LICENSE("GPL"); 525 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 526