drivers/char/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
  35 #include <asm/io.h>
  36 #include <asm/uaccess.h>
  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 static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
  64 module_param(timeout, int, 0);
  65 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  66
  67 static int use_gpio = 0; /* Use the pic (for a1d revision alim7101) */
  68 module_param(use_gpio, int, 0);
  69 MODULE_PARM_DESC(use_gpio, "Use the gpio watchdog.  (required by old cobalt boards)");
  70
  71 static void wdt_timer_ping(unsigned long);
  72 static struct timer_list timer;
  73 static unsigned long next_heartbeat;
  74 static unsigned long wdt_is_open;
  75 static char wdt_expect_close;
  76 static struct pci_dev *alim7101_pmu;
  77
  78 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  79 static int nowayout = 1;
  80 #else
  81 static int nowayout = 0;
  82 #endif
  83
  84 module_param(nowayout, int, 0);
  85 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_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         {
 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, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
 103                 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
 104                 if (use_gpio) {
 105                         pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
 106                         pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp
 107                                         | 0x20);
 108                         pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp
 109                                         & ~0x20);
 110                 }
 111         } else {
 112                 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
 113         }
 114         /* Re-set the timer interval */
 115         timer.expires = jiffies + WDT_INTERVAL;
 116         add_timer(&timer);
 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, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
 130                 if (use_gpio) {
 131                         pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
 132                         pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp & ~0x20);
 133                 }
 134
 135         } else {
 136                 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
 137                 if (use_gpio) {
 138                         pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
 139                         pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp | 0x20);
 140                 }
 141         }
 142 }
 143
 144 static void wdt_startup(void)
 145 {
 146         next_heartbeat = jiffies + (timeout * HZ);
 147
 148         /* We must enable before we kick off the timer in case the timer
 149            occurs as we ping it */
 150
 151         wdt_change(WDT_ENABLE);
 152
 153         /* Start the timer */
 154         timer.expires = jiffies + WDT_INTERVAL;
 155         add_timer(&timer);
 156
 157
 158         printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
 159 }
 160
 161 static void wdt_turnoff(void)
 162 {
 163         /* Stop the timer */
 164         del_timer_sync(&timer);
 165         wdt_change(WDT_DISABLE);
 166         printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
 167 }
 168
 169 static void wdt_keepalive(void)
 170 {
 171         /* user land ping */
 172         next_heartbeat = jiffies + (timeout * HZ);
 173 }
 174
 175 /*
 176  * /dev/watchdog handling
 177  */
 178
 179 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
 180 {
 181         /* See if we got the magic character 'V' and reload the timer */
 182         if(count) {
 183                 if (!nowayout) {
 184                         size_t ofs;
 185
 186                         /* note: just in case someone wrote the magic character
 187                          * five months ago... */
 188                         wdt_expect_close = 0;
 189
 190                         /* now scan */
 191                         for (ofs = 0; ofs != count; ofs++) {
 192                                 char c;
 193                                 if (get_user(c, buf+ofs))
 194                                         return -EFAULT;
 195                                 if (c == 'V')
 196                                         wdt_expect_close = 42;
 197                         }
 198                 }
 199                 /* someone wrote to us, we should restart timer */
 200                 wdt_keepalive();
 201         }
 202         return count;
 203 }
 204
 205 static int fop_open(struct inode * inode, struct file * file)
 206 {
 207         /* Just in case we're already talking to someone... */
 208         if(test_and_set_bit(0, &wdt_is_open))
 209                 return -EBUSY;
 210         /* Good, fire up the show */
 211         wdt_startup();
 212         return nonseekable_open(inode, file);
 213 }
 214
 215 static int fop_close(struct inode * inode, struct file * file)
 216 {
 217         if(wdt_expect_close == 42)
 218                 wdt_turnoff();
 219         else {
 220                 /* wim: shouldn't there be a: del_timer(&timer); */
 221                 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
 222         }
 223         clear_bit(0, &wdt_is_open);
 224         wdt_expect_close = 0;
 225         return 0;
 226 }
 227
 228 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 229 {
 230         void __user *argp = (void __user *)arg;
 231         int __user *p = argp;
 232         static struct watchdog_info ident =
 233         {
 234                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 235                 .firmware_version = 1,
 236                 .identity = "ALiM7101",
 237         };
 238
 239         switch(cmd)
 240         {
 241                 case WDIOC_GETSUPPORT:
 242                         return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
 243                 case WDIOC_GETSTATUS:
 244                 case WDIOC_GETBOOTSTATUS:
 245                         return put_user(0, p);
 246                 case WDIOC_KEEPALIVE:
 247                         wdt_keepalive();
 248                         return 0;
 249                 case WDIOC_SETOPTIONS:
 250                 {
 251                         int new_options, retval = -EINVAL;
 252
 253                         if(get_user(new_options, p))
 254                                 return -EFAULT;
 255
 256                         if(new_options & WDIOS_DISABLECARD) {
 257                                 wdt_turnoff();
 258                                 retval = 0;
 259                         }
 260
 261                         if(new_options & WDIOS_ENABLECARD) {
 262                                 wdt_startup();
 263                                 retval = 0;
 264                         }
 265
 266                         return retval;
 267                 }
 268                 case WDIOC_SETTIMEOUT:
 269                 {
 270                         int new_timeout;
 271
 272                         if(get_user(new_timeout, p))
 273                                 return -EFAULT;
 274
 275                         if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
 276                                 return -EINVAL;
 277
 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 -ENOIOCTLCMD;
 286         }
 287 }
 288
 289 static 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         .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, unsigned long code, void *unused)
 309 {
 310         if (code==SYS_DOWN || code==SYS_HALT)
 311                 wdt_turnoff();
 312
 313         if (code==SYS_RESTART) {
 314                 /*
 315                  * Cobalt devices have no way of rebooting themselves other than
 316                  * getting the watchdog to pull reset, so we restart the watchdog on
 317                  * reboot with no heartbeat
 318                  */
 319                 wdt_change(WDT_ENABLE);
 320                 printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n");
 321         }
 322         return NOTIFY_DONE;
 323 }
 324
 325 /*
 326  *      The WDT needs to learn about soft shutdowns in order to
 327  *      turn the timebomb registers off.
 328  */
 329
 330 static struct notifier_block wdt_notifier=
 331 {
 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 }
 342
 343 static int __init alim7101_wdt_init(void)
 344 {
 345         int rc = -EBUSY;
 346         struct pci_dev *ali1543_south;
 347         char tmp;
 348
 349         printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
 350         alim7101_pmu = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,NULL);
 351         if (!alim7101_pmu) {
 352                 printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n");
 353                 return -EBUSY;
 354         }
 355
 356         /* Set the WDT in the PMU to 1 second */
 357         pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
 358
 359         ali1543_south = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, NULL);
 360         if (!ali1543_south) {
 361                 printk(KERN_INFO PFX "ALi 1543 South-Bridge not present - WDT not set\n");
 362                 return -EBUSY;
 363         }
 364         pci_read_config_byte(ali1543_south, 0x5e, &tmp);
 365         if ((tmp & 0x1e) == 0x00) {
 366                 if (!use_gpio) {
 367                         printk(KERN_INFO PFX "Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
 368                         return -EBUSY;
 369                 }
 370                 nowayout = 1;
 371         } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
 372                 printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
 373                 return -EBUSY;
 374         }
 375
 376         if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
 377         {
 378                 timeout = WATCHDOG_TIMEOUT;
 379                 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
 380                         timeout);
 381         }
 382
 383         init_timer(&timer);
 384         timer.function = wdt_timer_ping;
 385         timer.data = 1;
 386
 387         rc = misc_register(&wdt_miscdev);
 388         if (rc) {
 389                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 390                         wdt_miscdev.minor, rc);
 391                 goto err_out;
 392         }
 393
 394         rc = register_reboot_notifier(&wdt_notifier);
 395         if (rc) {
 396                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 397                         rc);
 398                 goto err_out_miscdev;
 399         }
 400
 401         if (nowayout) {
 402                 __module_get(THIS_MODULE);
 403         }
 404
 405         printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
 406                 timeout, nowayout);
 407         return 0;
 408
 409 err_out_miscdev:
 410         misc_deregister(&wdt_miscdev);
 411 err_out:
 412         return rc;
 413 }
 414
 415 module_init(alim7101_wdt_init);
 416 module_exit(alim7101_wdt_unload);
 417
 418 MODULE_AUTHOR("Steve Hill");
 419 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
 420 MODULE_LICENSE("GPL");
 421 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);