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