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 300641-004 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/platform_device.h> 38 #include <linux/init.h> 39 #include <linux/pci.h> 40 #include <linux/ioport.h> 41 #include <linux/uaccess.h> 42 #include <linux/io.h> 43 44 /* Module and version information */ 45 #define ESB_VERSION "0.04" 46 #define ESB_MODULE_NAME "i6300ESB timer" 47 #define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION 48 #define PFX ESB_MODULE_NAME ": " 49 50 /* PCI configuration registers */ 51 #define ESB_CONFIG_REG 0x60 /* Config register */ 52 #define ESB_LOCK_REG 0x68 /* WDT lock register */ 53 54 /* Memory mapped registers */ 55 #define ESB_TIMER1_REG BASEADDR + 0x00 /* Timer1 value after each reset */ 56 #define ESB_TIMER2_REG BASEADDR + 0x04 /* Timer2 value after each reset */ 57 #define ESB_GINTSR_REG BASEADDR + 0x08 /* General Interrupt Status Register */ 58 #define ESB_RELOAD_REG BASEADDR + 0x0c /* Reload register */ 59 60 /* Lock register bits */ 61 #define ESB_WDT_FUNC (0x01 << 2) /* Watchdog functionality */ 62 #define ESB_WDT_ENABLE (0x01 << 1) /* Enable WDT */ 63 #define ESB_WDT_LOCK (0x01 << 0) /* Lock (nowayout) */ 64 65 /* Config register bits */ 66 #define ESB_WDT_REBOOT (0x01 << 5) /* Enable reboot on timeout */ 67 #define ESB_WDT_FREQ (0x01 << 2) /* Decrement frequency */ 68 #define ESB_WDT_INTTYPE (0x11 << 0) /* Interrupt type on timer1 timeout */ 69 70 /* Reload register bits */ 71 #define ESB_WDT_RELOAD (0x01 << 8) /* prevent timeout */ 72 73 /* Magic constants */ 74 #define ESB_UNLOCK1 0x80 /* Step 1 to unlock reset registers */ 75 #define ESB_UNLOCK2 0x86 /* Step 2 to unlock reset registers */ 76 77 /* internal variables */ 78 static void __iomem *BASEADDR; 79 static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */ 80 static unsigned long timer_alive; 81 static struct pci_dev *esb_pci; 82 static unsigned short triggered; /* The status of the watchdog upon boot */ 83 static char esb_expect_close; 84 static struct platform_device *esb_platform_device; 85 86 /* module parameters */ 87 /* 30 sec default heartbeat (1 < heartbeat < 2*1023) */ 88 #define WATCHDOG_HEARTBEAT 30 89 static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */ 90 91 module_param(heartbeat, int, 0); 92 MODULE_PARM_DESC(heartbeat, 93 "Watchdog heartbeat in seconds. (1<heartbeat<2046, default=" 94 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")"); 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 /* 103 * Some i6300ESB specific functions 104 */ 105 106 /* 107 * Prepare for reloading the timer by unlocking the proper registers. 108 * This is performed by first writing 0x80 followed by 0x86 to the 109 * reload register. After this the appropriate registers can be written 110 * to once before they need to be unlocked again. 111 */ 112 static inline void esb_unlock_registers(void) 113 { 114 writeb(ESB_UNLOCK1, ESB_RELOAD_REG); 115 writeb(ESB_UNLOCK2, ESB_RELOAD_REG); 116 } 117 118 static int esb_timer_start(void) 119 { 120 u8 val; 121 122 spin_lock(&esb_lock); 123 esb_unlock_registers(); 124 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG); 125 /* Enable or Enable + Lock? */ 126 val = 0x02 | (nowayout ? 0x01 : 0x00); 127 pci_write_config_byte(esb_pci, ESB_LOCK_REG, val); 128 spin_unlock(&esb_lock); 129 return 0; 130 } 131 132 static int esb_timer_stop(void) 133 { 134 u8 val; 135 136 spin_lock(&esb_lock); 137 /* First, reset timers as suggested by the docs */ 138 esb_unlock_registers(); 139 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG); 140 /* Then disable the WDT */ 141 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0); 142 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val); 143 spin_unlock(&esb_lock); 144 145 /* Returns 0 if the timer was disabled, non-zero otherwise */ 146 return (val & 0x01); 147 } 148 149 static void esb_timer_keepalive(void) 150 { 151 spin_lock(&esb_lock); 152 esb_unlock_registers(); 153 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG); 154 /* FIXME: Do we need to flush anything here? */ 155 spin_unlock(&esb_lock); 156 } 157 158 static int esb_timer_set_heartbeat(int time) 159 { 160 u32 val; 161 162 if (time < 0x1 || time > (2 * 0x03ff)) 163 return -EINVAL; 164 165 spin_lock(&esb_lock); 166 167 /* We shift by 9, so if we are passed a value of 1 sec, 168 * val will be 1 << 9 = 512, then write that to two 169 * timers => 2 * 512 = 1024 (which is decremented at 1KHz) 170 */ 171 val = time << 9; 172 173 /* Write timer 1 */ 174 esb_unlock_registers(); 175 writel(val, ESB_TIMER1_REG); 176 177 /* Write timer 2 */ 178 esb_unlock_registers(); 179 writel(val, ESB_TIMER2_REG); 180 181 /* Reload */ 182 esb_unlock_registers(); 183 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG); 184 185 /* FIXME: Do we need to flush everything out? */ 186 187 /* Done */ 188 heartbeat = time; 189 spin_unlock(&esb_lock); 190 return 0; 191 } 192 193 static int esb_timer_read(void) 194 { 195 u32 count; 196 197 /* This isn't documented, and doesn't take into 198 * acount which stage is running, but it looks 199 * like a 20 bit count down, so we might as well report it. 200 */ 201 pci_read_config_dword(esb_pci, 0x64, &count); 202 return (int)count; 203 } 204 205 /* 206 * /dev/watchdog handling 207 */ 208 209 static int esb_open(struct inode *inode, struct file *file) 210 { 211 /* /dev/watchdog can only be opened once */ 212 if (test_and_set_bit(0, &timer_alive)) 213 return -EBUSY; 214 215 /* Reload and activate timer */ 216 esb_timer_start(); 217 218 return nonseekable_open(inode, file); 219 } 220 221 static int esb_release(struct inode *inode, struct file *file) 222 { 223 /* Shut off the timer. */ 224 if (esb_expect_close == 42) 225 esb_timer_stop(); 226 else { 227 printk(KERN_CRIT PFX 228 "Unexpected close, not stopping watchdog!\n"); 229 esb_timer_keepalive(); 230 } 231 clear_bit(0, &timer_alive); 232 esb_expect_close = 0; 233 return 0; 234 } 235 236 static ssize_t esb_write(struct file *file, const char __user *data, 237 size_t len, loff_t *ppos) 238 { 239 /* See if we got the magic character 'V' and reload the timer */ 240 if (len) { 241 if (!nowayout) { 242 size_t i; 243 244 /* note: just in case someone wrote the magic character 245 * five months ago... */ 246 esb_expect_close = 0; 247 248 /* scan to see whether or not we got the 249 * magic character */ 250 for (i = 0; i != len; i++) { 251 char c; 252 if (get_user(c, data + i)) 253 return -EFAULT; 254 if (c == 'V') 255 esb_expect_close = 42; 256 } 257 } 258 259 /* someone wrote to us, we should reload the timer */ 260 esb_timer_keepalive(); 261 } 262 return len; 263 } 264 265 static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 266 { 267 int new_options, retval = -EINVAL; 268 int new_heartbeat; 269 void __user *argp = (void __user *)arg; 270 int __user *p = argp; 271 static struct watchdog_info ident = { 272 .options = WDIOF_SETTIMEOUT | 273 WDIOF_KEEPALIVEPING | 274 WDIOF_MAGICCLOSE, 275 .firmware_version = 0, 276 .identity = ESB_MODULE_NAME, 277 }; 278 279 switch (cmd) { 280 case WDIOC_GETSUPPORT: 281 return copy_to_user(argp, &ident, 282 sizeof(ident)) ? -EFAULT : 0; 283 284 case WDIOC_GETSTATUS: 285 return put_user(esb_timer_read(), p); 286 287 case WDIOC_GETBOOTSTATUS: 288 return put_user(triggered, p); 289 290 case WDIOC_SETOPTIONS: 291 { 292 if (get_user(new_options, p)) 293 return -EFAULT; 294 295 if (new_options & WDIOS_DISABLECARD) { 296 esb_timer_stop(); 297 retval = 0; 298 } 299 300 if (new_options & WDIOS_ENABLECARD) { 301 esb_timer_start(); 302 retval = 0; 303 } 304 return retval; 305 } 306 case WDIOC_KEEPALIVE: 307 esb_timer_keepalive(); 308 return 0; 309 310 case WDIOC_SETTIMEOUT: 311 { 312 if (get_user(new_heartbeat, p)) 313 return -EFAULT; 314 if (esb_timer_set_heartbeat(new_heartbeat)) 315 return -EINVAL; 316 esb_timer_keepalive(); 317 /* Fall */ 318 } 319 case WDIOC_GETTIMEOUT: 320 return put_user(heartbeat, p); 321 default: 322 return -ENOTTY; 323 } 324 } 325 326 /* 327 * Kernel Interfaces 328 */ 329 330 static const struct file_operations esb_fops = { 331 .owner = THIS_MODULE, 332 .llseek = no_llseek, 333 .write = esb_write, 334 .unlocked_ioctl = esb_ioctl, 335 .open = esb_open, 336 .release = esb_release, 337 }; 338 339 static struct miscdevice esb_miscdev = { 340 .minor = WATCHDOG_MINOR, 341 .name = "watchdog", 342 .fops = &esb_fops, 343 }; 344 345 /* 346 * Data for PCI driver interface 347 * 348 * This data only exists for exporting the supported 349 * PCI ids via MODULE_DEVICE_TABLE. We do not actually 350 * register a pci_driver, because someone else might one day 351 * want to register another driver on the same PCI id. 352 */ 353 static struct pci_device_id esb_pci_tbl[] = { 354 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), }, 355 { 0, }, /* End of list */ 356 }; 357 MODULE_DEVICE_TABLE(pci, esb_pci_tbl); 358 359 /* 360 * Init & exit routines 361 */ 362 363 static unsigned char __devinit esb_getdevice(void) 364 { 365 u8 val1; 366 unsigned short val2; 367 /* 368 * Find the PCI device 369 */ 370 371 esb_pci = pci_get_device(PCI_VENDOR_ID_INTEL, 372 PCI_DEVICE_ID_INTEL_ESB_9, NULL); 373 374 if (esb_pci) { 375 if (pci_enable_device(esb_pci)) { 376 printk(KERN_ERR PFX "failed to enable device\n"); 377 goto err_devput; 378 } 379 380 if (pci_request_region(esb_pci, 0, ESB_MODULE_NAME)) { 381 printk(KERN_ERR PFX "failed to request region\n"); 382 goto err_disable; 383 } 384 385 BASEADDR = pci_ioremap_bar(esb_pci, 0); 386 if (BASEADDR == NULL) { 387 /* Something's wrong here, BASEADDR has to be set */ 388 printk(KERN_ERR PFX "failed to get BASEADDR\n"); 389 goto err_release; 390 } 391 392 /* 393 * The watchdog has two timers, it can be setup so that the 394 * expiry of timer1 results in an interrupt and the expiry of 395 * timer2 results in a reboot. We set it to not generate 396 * any interrupts as there is not much we can do with it 397 * right now. 398 * 399 * We also enable reboots and set the timer frequency to 400 * the PCI clock divided by 2^15 (approx 1KHz). 401 */ 402 pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003); 403 404 /* Check that the WDT isn't already locked */ 405 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1); 406 if (val1 & ESB_WDT_LOCK) 407 printk(KERN_WARNING PFX "nowayout already set\n"); 408 409 /* Set the timer to watchdog mode and disable it for now */ 410 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00); 411 412 /* Check if the watchdog was previously triggered */ 413 esb_unlock_registers(); 414 val2 = readw(ESB_RELOAD_REG); 415 triggered = (val2 & (0x01 << 9) >> 9); 416 417 /* Reset trigger flag and timers */ 418 esb_unlock_registers(); 419 writew((0x11 << 8), ESB_RELOAD_REG); 420 421 /* Done */ 422 return 1; 423 424 err_release: 425 pci_release_region(esb_pci, 0); 426 err_disable: 427 pci_disable_device(esb_pci); 428 err_devput: 429 pci_dev_put(esb_pci); 430 } 431 return 0; 432 } 433 434 static int __devinit esb_probe(struct platform_device *dev) 435 { 436 int ret; 437 438 /* Check whether or not the hardware watchdog is there */ 439 if (!esb_getdevice() || esb_pci == NULL) 440 return -ENODEV; 441 442 /* Check that the heartbeat value is within it's range; 443 if not reset to the default */ 444 if (esb_timer_set_heartbeat(heartbeat)) { 445 esb_timer_set_heartbeat(WATCHDOG_HEARTBEAT); 446 printk(KERN_INFO PFX 447 "heartbeat value must be 1<heartbeat<2046, using %d\n", 448 heartbeat); 449 } 450 451 ret = misc_register(&esb_miscdev); 452 if (ret != 0) { 453 printk(KERN_ERR PFX 454 "cannot register miscdev on minor=%d (err=%d)\n", 455 WATCHDOG_MINOR, ret); 456 goto err_unmap; 457 } 458 esb_timer_stop(); 459 printk(KERN_INFO PFX 460 "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n", 461 BASEADDR, heartbeat, nowayout); 462 return 0; 463 464 err_unmap: 465 iounmap(BASEADDR); 466 /* err_release: */ 467 pci_release_region(esb_pci, 0); 468 /* err_disable: */ 469 pci_disable_device(esb_pci); 470 /* err_devput: */ 471 pci_dev_put(esb_pci); 472 return ret; 473 } 474 475 static int __devexit esb_remove(struct platform_device *dev) 476 { 477 /* Stop the timer before we leave */ 478 if (!nowayout) 479 esb_timer_stop(); 480 481 /* Deregister */ 482 misc_deregister(&esb_miscdev); 483 iounmap(BASEADDR); 484 pci_release_region(esb_pci, 0); 485 pci_disable_device(esb_pci); 486 pci_dev_put(esb_pci); 487 return 0; 488 } 489 490 static void esb_shutdown(struct platform_device *dev) 491 { 492 esb_timer_stop(); 493 } 494 495 static struct platform_driver esb_platform_driver = { 496 .probe = esb_probe, 497 .remove = __devexit_p(esb_remove), 498 .shutdown = esb_shutdown, 499 .driver = { 500 .owner = THIS_MODULE, 501 .name = ESB_MODULE_NAME, 502 }, 503 }; 504 505 static int __init watchdog_init(void) 506 { 507 int err; 508 509 printk(KERN_INFO PFX "Intel 6300ESB WatchDog Timer Driver v%s\n", 510 ESB_VERSION); 511 512 err = platform_driver_register(&esb_platform_driver); 513 if (err) 514 return err; 515 516 esb_platform_device = platform_device_register_simple(ESB_MODULE_NAME, 517 -1, NULL, 0); 518 if (IS_ERR(esb_platform_device)) { 519 err = PTR_ERR(esb_platform_device); 520 goto unreg_platform_driver; 521 } 522 523 return 0; 524 525 unreg_platform_driver: 526 platform_driver_unregister(&esb_platform_driver); 527 return err; 528 } 529 530 static void __exit watchdog_cleanup(void) 531 { 532 platform_device_unregister(esb_platform_device); 533 platform_driver_unregister(&esb_platform_driver); 534 printk(KERN_INFO PFX "Watchdog Module Unloaded.\n"); 535 } 536 537 module_init(watchdog_init); 538 module_exit(watchdog_cleanup); 539 540 MODULE_AUTHOR("Ross Biro and David Härdeman"); 541 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets"); 542 MODULE_LICENSE("GPL"); 543 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 544