drivers/watchdog/alim7101_wdt.c

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