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 #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(unsigned long);
  74 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
  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(unsigned long data)
  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 nonseekable_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                 /* Fall through */
 281         }
 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 /*
 305  *      Notifier for system down
 306  */
 307
 308 static int wdt_notify_sys(struct notifier_block *this,
 309                                         unsigned long code, void *unused)
 310 {
 311         if (code == SYS_DOWN || code == SYS_HALT)
 312                 wdt_turnoff();
 313
 314         if (code == SYS_RESTART) {
 315                 /*
 316                  * Cobalt devices have no way of rebooting themselves other
 317                  * than getting the watchdog to pull reset, so we restart the
 318                  * watchdog on reboot with no heartbeat
 319                  */
 320                 wdt_change(WDT_ENABLE);
 321                 pr_info("Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second\n");
 322         }
 323         return NOTIFY_DONE;
 324 }
 325
 326 /*
 327  *      The WDT needs to learn about soft shutdowns in order to
 328  *      turn the timebomb registers off.
 329  */
 330
 331 static struct notifier_block wdt_notifier = {
 332         .notifier_call = wdt_notify_sys,
 333 };
 334
 335 static void __exit alim7101_wdt_unload(void)
 336 {
 337         wdt_turnoff();
 338         /* Deregister */
 339         misc_deregister(&wdt_miscdev);
 340         unregister_reboot_notifier(&wdt_notifier);
 341         pci_dev_put(alim7101_pmu);
 342 }
 343
 344 static int __init alim7101_wdt_init(void)
 345 {
 346         int rc = -EBUSY;
 347         struct pci_dev *ali1543_south;
 348         char tmp;
 349
 350         pr_info("Steve Hill <steve@navaho.co.uk>\n");
 351         alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
 352                 NULL);
 353         if (!alim7101_pmu) {
 354                 pr_info("ALi M7101 PMU not present - WDT not set\n");
 355                 return -EBUSY;
 356         }
 357
 358         /* Set the WDT in the PMU to 1 second */
 359         pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
 360
 361         ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
 362                 NULL);
 363         if (!ali1543_south) {
 364                 pr_info("ALi 1543 South-Bridge not present - WDT not set\n");
 365                 goto err_out;
 366         }
 367         pci_read_config_byte(ali1543_south, 0x5e, &tmp);
 368         pci_dev_put(ali1543_south);
 369         if ((tmp & 0x1e) == 0x00) {
 370                 if (!use_gpio) {
 371                         pr_info("Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
 372                         goto err_out;
 373                 }
 374                 nowayout = 1;
 375         } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
 376                 pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
 377                 goto err_out;
 378         }
 379
 380         if (timeout < 1 || timeout > 3600) {
 381                 /* arbitrary upper limit */
 382                 timeout = WATCHDOG_TIMEOUT;
 383                 pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
 384                         timeout);
 385         }
 386
 387         rc = register_reboot_notifier(&wdt_notifier);
 388         if (rc) {
 389                 pr_err("cannot register reboot notifier (err=%d)\n", rc);
 390                 goto err_out;
 391         }
 392
 393         rc = misc_register(&wdt_miscdev);
 394         if (rc) {
 395                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 396                        wdt_miscdev.minor, rc);
 397                 goto err_out_reboot;
 398         }
 399
 400         if (nowayout)
 401                 __module_get(THIS_MODULE);
 402
 403         pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
 404                 timeout, nowayout);
 405         return 0;
 406
 407 err_out_reboot:
 408         unregister_reboot_notifier(&wdt_notifier);
 409 err_out:
 410         pci_dev_put(alim7101_pmu);
 411         return rc;
 412 }
 413
 414 module_init(alim7101_wdt_init);
 415 module_exit(alim7101_wdt_unload);
 416
 417 static DEFINE_PCI_DEVICE_TABLE(alim7101_pci_tbl) __used = {
 418         { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
 419         { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
 420         { }
 421 };
 422
 423 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
 424
 425 MODULE_AUTHOR("Steve Hill");
 426 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
 427 MODULE_LICENSE("GPL");
 428 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);