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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 23 24 #include <linux/module.h> 25 #include <linux/moduleparam.h> 26 #include <linux/types.h> 27 #include <linux/timer.h> 28 #include <linux/miscdevice.h> 29 #include <linux/watchdog.h> 30 #include <linux/ioport.h> 31 #include <linux/notifier.h> 32 #include <linux/reboot.h> 33 #include <linux/init.h> 34 #include <linux/fs.h> 35 #include <linux/pci.h> 36 #include <linux/io.h> 37 #include <linux/uaccess.h> 38 39 40 #define WDT_ENABLE 0x9C 41 #define WDT_DISABLE 0x8C 42 43 #define ALI_7101_WDT 0x92 44 #define ALI_7101_GPIO 0x7D 45 #define ALI_7101_GPIO_O 0x7E 46 #define ALI_WDT_ARM 0x01 47 48 /* 49 * We're going to use a 1 second timeout. 50 * If we reset the watchdog every ~250ms we should be safe. */ 51 52 #define WDT_INTERVAL (HZ/4+1) 53 54 /* 55 * We must not require too good response from the userspace daemon. 56 * Here we require the userspace daemon to send us a heartbeat 57 * char to /dev/watchdog every 30 seconds. 58 */ 59 60 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ 61 /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ 62 static int timeout = WATCHDOG_TIMEOUT; 63 module_param(timeout, int, 0); 64 MODULE_PARM_DESC(timeout, 65 "Watchdog timeout in seconds. (1<=timeout<=3600, default=" 66 __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 67 68 static int use_gpio; /* Use the pic (for a1d revision alim7101) */ 69 module_param(use_gpio, int, 0); 70 MODULE_PARM_DESC(use_gpio, 71 "Use the gpio watchdog (required by old cobalt boards)."); 72 73 static void wdt_timer_ping(struct timer_list *); 74 static DEFINE_TIMER(timer, wdt_timer_ping); 75 static unsigned long next_heartbeat; 76 static unsigned long wdt_is_open; 77 static char wdt_expect_close; 78 static struct pci_dev *alim7101_pmu; 79 80 static bool nowayout = WATCHDOG_NOWAYOUT; 81 module_param(nowayout, bool, 0); 82 MODULE_PARM_DESC(nowayout, 83 "Watchdog cannot be stopped once started (default=" 84 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 85 86 /* 87 * Whack the dog 88 */ 89 90 static void wdt_timer_ping(struct timer_list *unused) 91 { 92 /* If we got a heartbeat pulse within the WDT_US_INTERVAL 93 * we agree to ping the WDT 94 */ 95 char tmp; 96 97 if (time_before(jiffies, next_heartbeat)) { 98 /* Ping the WDT (this is actually a disarm/arm sequence) */ 99 pci_read_config_byte(alim7101_pmu, 0x92, &tmp); 100 pci_write_config_byte(alim7101_pmu, 101 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); 102 pci_write_config_byte(alim7101_pmu, 103 ALI_7101_WDT, (tmp | ALI_WDT_ARM)); 104 if (use_gpio) { 105 pci_read_config_byte(alim7101_pmu, 106 ALI_7101_GPIO_O, &tmp); 107 pci_write_config_byte(alim7101_pmu, 108 ALI_7101_GPIO_O, tmp | 0x20); 109 pci_write_config_byte(alim7101_pmu, 110 ALI_7101_GPIO_O, tmp & ~0x20); 111 } 112 } else { 113 pr_warn("Heartbeat lost! Will not ping the watchdog\n"); 114 } 115 /* Re-set the timer interval */ 116 mod_timer(&timer, jiffies + WDT_INTERVAL); 117 } 118 119 /* 120 * Utility routines 121 */ 122 123 static void wdt_change(int writeval) 124 { 125 char tmp; 126 127 pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp); 128 if (writeval == WDT_ENABLE) { 129 pci_write_config_byte(alim7101_pmu, 130 ALI_7101_WDT, (tmp | ALI_WDT_ARM)); 131 if (use_gpio) { 132 pci_read_config_byte(alim7101_pmu, 133 ALI_7101_GPIO_O, &tmp); 134 pci_write_config_byte(alim7101_pmu, 135 ALI_7101_GPIO_O, tmp & ~0x20); 136 } 137 138 } else { 139 pci_write_config_byte(alim7101_pmu, 140 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); 141 if (use_gpio) { 142 pci_read_config_byte(alim7101_pmu, 143 ALI_7101_GPIO_O, &tmp); 144 pci_write_config_byte(alim7101_pmu, 145 ALI_7101_GPIO_O, tmp | 0x20); 146 } 147 } 148 } 149 150 static void wdt_startup(void) 151 { 152 next_heartbeat = jiffies + (timeout * HZ); 153 154 /* We must enable before we kick off the timer in case the timer 155 occurs as we ping it */ 156 157 wdt_change(WDT_ENABLE); 158 159 /* Start the timer */ 160 mod_timer(&timer, jiffies + WDT_INTERVAL); 161 162 pr_info("Watchdog timer is now enabled\n"); 163 } 164 165 static void wdt_turnoff(void) 166 { 167 /* Stop the timer */ 168 del_timer_sync(&timer); 169 wdt_change(WDT_DISABLE); 170 pr_info("Watchdog timer is now disabled...\n"); 171 } 172 173 static void wdt_keepalive(void) 174 { 175 /* user land ping */ 176 next_heartbeat = jiffies + (timeout * HZ); 177 } 178 179 /* 180 * /dev/watchdog handling 181 */ 182 183 static ssize_t fop_write(struct file *file, const char __user *buf, 184 size_t count, loff_t *ppos) 185 { 186 /* See if we got the magic character 'V' and reload the timer */ 187 if (count) { 188 if (!nowayout) { 189 size_t ofs; 190 191 /* note: just in case someone wrote the magic character 192 * five months ago... */ 193 wdt_expect_close = 0; 194 195 /* now scan */ 196 for (ofs = 0; ofs != count; ofs++) { 197 char c; 198 if (get_user(c, buf + ofs)) 199 return -EFAULT; 200 if (c == 'V') 201 wdt_expect_close = 42; 202 } 203 } 204 /* someone wrote to us, we should restart timer */ 205 wdt_keepalive(); 206 } 207 return count; 208 } 209 210 static int fop_open(struct inode *inode, struct file *file) 211 { 212 /* Just in case we're already talking to someone... */ 213 if (test_and_set_bit(0, &wdt_is_open)) 214 return -EBUSY; 215 /* Good, fire up the show */ 216 wdt_startup(); 217 return stream_open(inode, file); 218 } 219 220 static int fop_close(struct inode *inode, struct file *file) 221 { 222 if (wdt_expect_close == 42) 223 wdt_turnoff(); 224 else { 225 /* wim: shouldn't there be a: del_timer(&timer); */ 226 pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); 227 } 228 clear_bit(0, &wdt_is_open); 229 wdt_expect_close = 0; 230 return 0; 231 } 232 233 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 234 { 235 void __user *argp = (void __user *)arg; 236 int __user *p = argp; 237 static const struct watchdog_info ident = { 238 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT 239 | WDIOF_MAGICCLOSE, 240 .firmware_version = 1, 241 .identity = "ALiM7101", 242 }; 243 244 switch (cmd) { 245 case WDIOC_GETSUPPORT: 246 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; 247 case WDIOC_GETSTATUS: 248 case WDIOC_GETBOOTSTATUS: 249 return put_user(0, p); 250 case WDIOC_SETOPTIONS: 251 { 252 int new_options, retval = -EINVAL; 253 254 if (get_user(new_options, p)) 255 return -EFAULT; 256 if (new_options & WDIOS_DISABLECARD) { 257 wdt_turnoff(); 258 retval = 0; 259 } 260 if (new_options & WDIOS_ENABLECARD) { 261 wdt_startup(); 262 retval = 0; 263 } 264 return retval; 265 } 266 case WDIOC_KEEPALIVE: 267 wdt_keepalive(); 268 return 0; 269 case WDIOC_SETTIMEOUT: 270 { 271 int new_timeout; 272 273 if (get_user(new_timeout, p)) 274 return -EFAULT; 275 /* arbitrary upper limit */ 276 if (new_timeout < 1 || new_timeout > 3600) 277 return -EINVAL; 278 timeout = new_timeout; 279 wdt_keepalive(); 280 } 281 /* Fall through */ 282 case WDIOC_GETTIMEOUT: 283 return put_user(timeout, p); 284 default: 285 return -ENOTTY; 286 } 287 } 288 289 static const struct file_operations wdt_fops = { 290 .owner = THIS_MODULE, 291 .llseek = no_llseek, 292 .write = fop_write, 293 .open = fop_open, 294 .release = fop_close, 295 .unlocked_ioctl = fop_ioctl, 296 }; 297 298 static struct miscdevice wdt_miscdev = { 299 .minor = WATCHDOG_MINOR, 300 .name = "watchdog", 301 .fops = &wdt_fops, 302 }; 303 304 static int wdt_restart_handle(struct notifier_block *this, unsigned long mode, 305 void *cmd) 306 { 307 /* 308 * Cobalt devices have no way of rebooting themselves other 309 * than getting the watchdog to pull reset, so we restart the 310 * watchdog on reboot with no heartbeat. 311 */ 312 wdt_change(WDT_ENABLE); 313 314 /* loop until the watchdog fires */ 315 while (true) 316 ; 317 318 return NOTIFY_DONE; 319 } 320 321 static struct notifier_block wdt_restart_handler = { 322 .notifier_call = wdt_restart_handle, 323 .priority = 128, 324 }; 325 326 /* 327 * Notifier for system down 328 */ 329 330 static int wdt_notify_sys(struct notifier_block *this, 331 unsigned long code, void *unused) 332 { 333 if (code == SYS_DOWN || code == SYS_HALT) 334 wdt_turnoff(); 335 336 return NOTIFY_DONE; 337 } 338 339 /* 340 * The WDT needs to learn about soft shutdowns in order to 341 * turn the timebomb registers off. 342 */ 343 344 static struct notifier_block wdt_notifier = { 345 .notifier_call = wdt_notify_sys, 346 }; 347 348 static void __exit alim7101_wdt_unload(void) 349 { 350 wdt_turnoff(); 351 /* Deregister */ 352 misc_deregister(&wdt_miscdev); 353 unregister_reboot_notifier(&wdt_notifier); 354 unregister_restart_handler(&wdt_restart_handler); 355 pci_dev_put(alim7101_pmu); 356 } 357 358 static int __init alim7101_wdt_init(void) 359 { 360 int rc = -EBUSY; 361 struct pci_dev *ali1543_south; 362 char tmp; 363 364 pr_info("Steve Hill <steve@navaho.co.uk>\n"); 365 alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101, 366 NULL); 367 if (!alim7101_pmu) { 368 pr_info("ALi M7101 PMU not present - WDT not set\n"); 369 return -EBUSY; 370 } 371 372 /* Set the WDT in the PMU to 1 second */ 373 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02); 374 375 ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, 376 NULL); 377 if (!ali1543_south) { 378 pr_info("ALi 1543 South-Bridge not present - WDT not set\n"); 379 goto err_out; 380 } 381 pci_read_config_byte(ali1543_south, 0x5e, &tmp); 382 pci_dev_put(ali1543_south); 383 if ((tmp & 0x1e) == 0x00) { 384 if (!use_gpio) { 385 pr_info("Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n"); 386 goto err_out; 387 } 388 nowayout = 1; 389 } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) { 390 pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n"); 391 goto err_out; 392 } 393 394 if (timeout < 1 || timeout > 3600) { 395 /* arbitrary upper limit */ 396 timeout = WATCHDOG_TIMEOUT; 397 pr_info("timeout value must be 1 <= x <= 3600, using %d\n", 398 timeout); 399 } 400 401 rc = register_reboot_notifier(&wdt_notifier); 402 if (rc) { 403 pr_err("cannot register reboot notifier (err=%d)\n", rc); 404 goto err_out; 405 } 406 407 rc = register_restart_handler(&wdt_restart_handler); 408 if (rc) { 409 pr_err("cannot register restart handler (err=%d)\n", rc); 410 goto err_out_reboot; 411 } 412 413 rc = misc_register(&wdt_miscdev); 414 if (rc) { 415 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 416 wdt_miscdev.minor, rc); 417 goto err_out_restart; 418 } 419 420 if (nowayout) 421 __module_get(THIS_MODULE); 422 423 pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n", 424 timeout, nowayout); 425 return 0; 426 427 err_out_restart: 428 unregister_restart_handler(&wdt_restart_handler); 429 err_out_reboot: 430 unregister_reboot_notifier(&wdt_notifier); 431 err_out: 432 pci_dev_put(alim7101_pmu); 433 return rc; 434 } 435 436 module_init(alim7101_wdt_init); 437 module_exit(alim7101_wdt_unload); 438 439 static const struct pci_device_id alim7101_pci_tbl[] __used = { 440 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) }, 441 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) }, 442 { } 443 }; 444 445 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl); 446 447 MODULE_AUTHOR("Steve Hill"); 448 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver"); 449 MODULE_LICENSE("GPL"); 450