1/* 2 * ALi M7101 PMU Computer Watchdog Timer driver 3 * 4 * Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net> 5 * and the Cobalt kernel WDT timer driver by Tim Hockin 6 * <thockin@cobaltnet.com> 7 * 8 * (c)2002 Steve Hill <steve@navaho.co.uk> 9 * 10 * This WDT driver is different from most other Linux WDT 11 * drivers in that the driver will ping the watchdog by itself, 12 * because this particular WDT has a very short timeout (1.6 13 * seconds) and it would be insane to count on any userspace 14 * daemon always getting scheduled within that time frame. 15 * 16 * Additions: 17 * Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs 18 * found on very old cobalt hardware. 19 * -- Mike Waychison <michael.waychison@sun.com> 20 */ 21 22#include <linux/module.h> 23#include <linux/moduleparam.h> 24#include <linux/types.h> 25#include <linux/timer.h> 26#include <linux/miscdevice.h> 27#include <linux/watchdog.h> 28#include <linux/ioport.h> 29#include <linux/notifier.h> 30#include <linux/reboot.h> 31#include <linux/init.h> 32#include <linux/fs.h> 33#include <linux/pci.h> 34#include <linux/io.h> 35#include <linux/uaccess.h> 36 37#include <asm/system.h> 38 39#define OUR_NAME "alim7101_wdt" 40#define PFX OUR_NAME ": " 41 42#define WDT_ENABLE 0x9C 43#define WDT_DISABLE 0x8C 44 45#define ALI_7101_WDT 0x92 46#define ALI_7101_GPIO 0x7D 47#define ALI_7101_GPIO_O 0x7E 48#define ALI_WDT_ARM 0x01 49 50/* 51 * We're going to use a 1 second timeout. 52 * If we reset the watchdog every ~250ms we should be safe. */ 53 54#define WDT_INTERVAL (HZ/4+1) 55 56/* 57 * We must not require too good response from the userspace daemon. 58 * Here we require the userspace daemon to send us a heartbeat 59 * char to /dev/watchdog every 30 seconds. 60 */ 61 62#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ 63/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ 64static int timeout = WATCHDOG_TIMEOUT; 65module_param(timeout, int, 0); 66MODULE_PARM_DESC(timeout, 67 "Watchdog timeout in seconds. (1<=timeout<=3600, default=" 68 __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 69 70static int use_gpio; /* Use the pic (for a1d revision alim7101) */ 71module_param(use_gpio, int, 0); 72MODULE_PARM_DESC(use_gpio, 73 "Use the gpio watchdog (required by old cobalt boards)."); 74 75static void wdt_timer_ping(unsigned long); 76static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1); 77static unsigned long next_heartbeat; 78static unsigned long wdt_is_open; 79static char wdt_expect_close; 80static struct pci_dev *alim7101_pmu; 81 82static int nowayout = WATCHDOG_NOWAYOUT; 83module_param(nowayout, int, 0); 84MODULE_PARM_DESC(nowayout, 85 "Watchdog cannot be stopped once started (default=" 86 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 87 88/* 89 * Whack the dog 90 */ 91 92static void wdt_timer_ping(unsigned long data) 93{ 94 /* If we got a heartbeat pulse within the WDT_US_INTERVAL 95 * we agree to ping the WDT 96 */ 97 char tmp; 98 99 if (time_before(jiffies, next_heartbeat)) { 100 /* Ping the WDT (this is actually a disarm/arm sequence) */ 101 pci_read_config_byte(alim7101_pmu, 0x92, &tmp); 102 pci_write_config_byte(alim7101_pmu, 103 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); 104 pci_write_config_byte(alim7101_pmu, 105 ALI_7101_WDT, (tmp | ALI_WDT_ARM)); 106 if (use_gpio) { 107 pci_read_config_byte(alim7101_pmu, 108 ALI_7101_GPIO_O, &tmp); 109 pci_write_config_byte(alim7101_pmu, 110 ALI_7101_GPIO_O, tmp | 0x20); 111 pci_write_config_byte(alim7101_pmu, 112 ALI_7101_GPIO_O, tmp & ~0x20); 113 } 114 } else { 115 printk(KERN_WARNING PFX 116 "Heartbeat lost! Will not ping the watchdog\n"); 117 } 118 /* Re-set the timer interval */ 119 mod_timer(&timer, jiffies + WDT_INTERVAL); 120} 121 122/* 123 * Utility routines 124 */ 125 126static void wdt_change(int writeval) 127{ 128 char tmp; 129 130 pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp); 131 if (writeval == WDT_ENABLE) { 132 pci_write_config_byte(alim7101_pmu, 133 ALI_7101_WDT, (tmp | ALI_WDT_ARM)); 134 if (use_gpio) { 135 pci_read_config_byte(alim7101_pmu, 136 ALI_7101_GPIO_O, &tmp); 137 pci_write_config_byte(alim7101_pmu, 138 ALI_7101_GPIO_O, tmp & ~0x20); 139 } 140 141 } else { 142 pci_write_config_byte(alim7101_pmu, 143 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); 144 if (use_gpio) { 145 pci_read_config_byte(alim7101_pmu, 146 ALI_7101_GPIO_O, &tmp); 147 pci_write_config_byte(alim7101_pmu, 148 ALI_7101_GPIO_O, tmp | 0x20); 149 } 150 } 151} 152 153static void wdt_startup(void) 154{ 155 next_heartbeat = jiffies + (timeout * HZ); 156 157 /* We must enable before we kick off the timer in case the timer 158 occurs as we ping it */ 159 160 wdt_change(WDT_ENABLE); 161 162 /* Start the timer */ 163 mod_timer(&timer, jiffies + WDT_INTERVAL); 164 165 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); 166} 167 168static void wdt_turnoff(void) 169{ 170 /* Stop the timer */ 171 del_timer_sync(&timer); 172 wdt_change(WDT_DISABLE); 173 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); 174} 175 176static void wdt_keepalive(void) 177{ 178 /* user land ping */ 179 next_heartbeat = jiffies + (timeout * HZ); 180} 181 182/* 183 * /dev/watchdog handling 184 */ 185 186static ssize_t fop_write(struct file *file, const char __user *buf, 187 size_t count, loff_t *ppos) 188{ 189 /* See if we got the magic character 'V' and reload the timer */ 190 if (count) { 191 if (!nowayout) { 192 size_t ofs; 193 194 /* note: just in case someone wrote the magic character 195 * five months ago... */ 196 wdt_expect_close = 0; 197 198 /* now scan */ 199 for (ofs = 0; ofs != count; ofs++) { 200 char c; 201 if (get_user(c, buf + ofs)) 202 return -EFAULT; 203 if (c == 'V') 204 wdt_expect_close = 42; 205 } 206 } 207 /* someone wrote to us, we should restart timer */ 208 wdt_keepalive(); 209 } 210 return count; 211} 212 213static int fop_open(struct inode *inode, struct file *file) 214{ 215 /* Just in case we're already talking to someone... */ 216 if (test_and_set_bit(0, &wdt_is_open)) 217 return -EBUSY; 218 /* Good, fire up the show */ 219 wdt_startup(); 220 return nonseekable_open(inode, file); 221} 222 223static int fop_close(struct inode *inode, struct file *file) 224{ 225 if (wdt_expect_close == 42) 226 wdt_turnoff(); 227 else { 228 /* wim: shouldn't there be a: del_timer(&timer); */ 229 printk(KERN_CRIT PFX 230 "device file closed unexpectedly. Will not stop the WDT!\n"); 231 } 232 clear_bit(0, &wdt_is_open); 233 wdt_expect_close = 0; 234 return 0; 235} 236 237static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 238{ 239 void __user *argp = (void __user *)arg; 240 int __user *p = argp; 241 static const struct watchdog_info ident = { 242 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT 243 | WDIOF_MAGICCLOSE, 244 .firmware_version = 1, 245 .identity = "ALiM7101", 246 }; 247 248 switch (cmd) { 249 case WDIOC_GETSUPPORT: 250 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; 251 case WDIOC_GETSTATUS: 252 case WDIOC_GETBOOTSTATUS: 253 return put_user(0, p); 254 case WDIOC_SETOPTIONS: 255 { 256 int new_options, retval = -EINVAL; 257 258 if (get_user(new_options, p)) 259 return -EFAULT; 260 if (new_options & WDIOS_DISABLECARD) { 261 wdt_turnoff(); 262 retval = 0; 263 } 264 if (new_options & WDIOS_ENABLECARD) { 265 wdt_startup(); 266 retval = 0; 267 } 268 return retval; 269 } 270 case WDIOC_KEEPALIVE: 271 wdt_keepalive(); 272 return 0; 273 case WDIOC_SETTIMEOUT: 274 { 275 int new_timeout; 276 277 if (get_user(new_timeout, p)) 278 return -EFAULT; 279 /* arbitrary upper limit */ 280 if (new_timeout < 1 || new_timeout > 3600) 281 return -EINVAL; 282 timeout = new_timeout; 283 wdt_keepalive(); 284 /* Fall through */ 285 } 286 case WDIOC_GETTIMEOUT: 287 return put_user(timeout, p); 288 default: 289 return -ENOTTY; 290 } 291} 292 293static const struct file_operations wdt_fops = { 294 .owner = THIS_MODULE, 295 .llseek = no_llseek, 296 .write = fop_write, 297 .open = fop_open, 298 .release = fop_close, 299 .unlocked_ioctl = fop_ioctl, 300}; 301 302static struct miscdevice wdt_miscdev = { 303 .minor = WATCHDOG_MINOR, 304 .name = "watchdog", 305 .fops = &wdt_fops, 306}; 307 308/* 309 * Notifier for system down 310 */ 311 312static int wdt_notify_sys(struct notifier_block *this, 313 unsigned long code, void *unused) 314{ 315 if (code == SYS_DOWN || code == SYS_HALT) 316 wdt_turnoff(); 317 318 if (code == SYS_RESTART) { 319 /* 320 * Cobalt devices have no way of rebooting themselves other 321 * than getting the watchdog to pull reset, so we restart the 322 * watchdog on reboot with no heartbeat 323 */ 324 wdt_change(WDT_ENABLE); 325 printk(KERN_INFO PFX "Watchdog timer is now enabled " 326 "with no heartbeat - should reboot in ~1 second.\n"); 327 } 328 return NOTIFY_DONE; 329} 330 331/* 332 * The WDT needs to learn about soft shutdowns in order to 333 * turn the timebomb registers off. 334 */ 335 336static struct notifier_block wdt_notifier = { 337 .notifier_call = wdt_notify_sys, 338}; 339 340static void __exit alim7101_wdt_unload(void) 341{ 342 wdt_turnoff(); 343 /* Deregister */ 344 misc_deregister(&wdt_miscdev); 345 unregister_reboot_notifier(&wdt_notifier); 346 pci_dev_put(alim7101_pmu); 347} 348 349static int __init alim7101_wdt_init(void) 350{ 351 int rc = -EBUSY; 352 struct pci_dev *ali1543_south; 353 char tmp; 354 355 printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n"); 356 alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101, 357 NULL); 358 if (!alim7101_pmu) { 359 printk(KERN_INFO PFX 360 "ALi M7101 PMU not present - WDT not set\n"); 361 return -EBUSY; 362 } 363 364 /* Set the WDT in the PMU to 1 second */ 365 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02); 366 367 ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, 368 NULL); 369 if (!ali1543_south) { 370 printk(KERN_INFO PFX 371 "ALi 1543 South-Bridge not present - WDT not set\n"); 372 goto err_out; 373 } 374 pci_read_config_byte(ali1543_south, 0x5e, &tmp); 375 pci_dev_put(ali1543_south); 376 if ((tmp & 0x1e) == 0x00) { 377 if (!use_gpio) { 378 printk(KERN_INFO PFX 379 "Detected old alim7101 revision 'a1d'. " 380 "If this is a cobalt board, set the 'use_gpio' " 381 "module parameter.\n"); 382 goto err_out; 383 } 384 nowayout = 1; 385 } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) { 386 printk(KERN_INFO PFX 387 "ALi 1543 South-Bridge does not have the correct " 388 "revision number (???1001?) - WDT not set\n"); 389 goto err_out; 390 } 391 392 if (timeout < 1 || timeout > 3600) { 393 /* arbitrary upper limit */ 394 timeout = WATCHDOG_TIMEOUT; 395 printk(KERN_INFO PFX 396 "timeout value must be 1 <= x <= 3600, using %d\n", 397 timeout); 398 } 399 400 rc = register_reboot_notifier(&wdt_notifier); 401 if (rc) { 402 printk(KERN_ERR PFX 403 "cannot register reboot notifier (err=%d)\n", rc); 404 goto err_out; 405 } 406 407 rc = misc_register(&wdt_miscdev); 408 if (rc) { 409 printk(KERN_ERR PFX 410 "cannot register miscdev on minor=%d (err=%d)\n", 411 wdt_miscdev.minor, rc); 412 goto err_out_reboot; 413 } 414 415 if (nowayout) 416 __module_get(THIS_MODULE); 417 418 printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. " 419 "timeout=%d sec (nowayout=%d)\n", 420 timeout, nowayout); 421 return 0; 422 423err_out_reboot: 424 unregister_reboot_notifier(&wdt_notifier); 425err_out: 426 pci_dev_put(alim7101_pmu); 427 return rc; 428} 429 430module_init(alim7101_wdt_init); 431module_exit(alim7101_wdt_unload); 432 433static struct pci_device_id alim7101_pci_tbl[] __devinitdata = { 434 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) }, 435 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) }, 436 { } 437}; 438 439MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl); 440 441MODULE_AUTHOR("Steve Hill"); 442MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver"); 443MODULE_LICENSE("GPL"); 444MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 445