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 #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 */
  64 static int timeout = WATCHDOG_TIMEOUT;
  65 module_param(timeout, int, 0);
  66 MODULE_PARM_DESC(timeout,
  67                 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
  68                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  69
  70 static int use_gpio; /* Use the pic (for a1d revision alim7101) */
  71 module_param(use_gpio, int, 0);
  72 MODULE_PARM_DESC(use_gpio,
  73                 "Use the gpio watchdog (required by old cobalt boards).");
  74
  75 static void wdt_timer_ping(unsigned long);
  76 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
  77 static unsigned long next_heartbeat;
  78 static unsigned long wdt_is_open;
  79 static char wdt_expect_close;
  80 static struct pci_dev *alim7101_pmu;
  81
  82 static int nowayout = WATCHDOG_NOWAYOUT;
  83 module_param(nowayout, int, 0);
  84 MODULE_PARM_DESC(nowayout,
  85                 "Watchdog cannot be stopped once started (default="
  86                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  87
  88 /*
  89  *      Whack the dog
  90  */
  91
  92 static 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
 126 static 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
 153 static 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
 168 static 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
 176 static void wdt_keepalive(void)
 177 {
 178         /* user land ping */
 179         next_heartbeat = jiffies + (timeout * HZ);
 180 }
 181
 182 /*
 183  * /dev/watchdog handling
 184  */
 185
 186 static 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
 213 static 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
 223 static 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
 237 static 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
 293 static 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
 302 static 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
 312 static 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
 336 static struct notifier_block wdt_notifier = {
 337         .notifier_call = wdt_notify_sys,
 338 };
 339
 340 static 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
 349 static 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
 423 err_out_reboot:
 424         unregister_reboot_notifier(&wdt_notifier);
 425 err_out:
 426         pci_dev_put(alim7101_pmu);
 427         return rc;
 428 }
 429
 430 module_init(alim7101_wdt_init);
 431 module_exit(alim7101_wdt_unload);
 432
 433 static DEFINE_PCI_DEVICE_TABLE(alim7101_pci_tbl) __used = {
 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
 439 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
 440
 441 MODULE_AUTHOR("Steve Hill");
 442 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
 443 MODULE_LICENSE("GPL");
 444 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);