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 DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
  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="
  81                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  82
  83 /*
  84  *      Whack the dog
  85  */
  86
  87 static void wdt_timer_ping(unsigned long data)
  88 {
  89         /* If we got a heartbeat pulse within the WDT_US_INTERVAL
  90          * we agree to ping the WDT
  91          */
  92         char    tmp;
  93
  94         if(time_before(jiffies, next_heartbeat))
  95         {
  96                 /* Ping the WDT (this is actually a disarm/arm sequence) */
  97                 pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
  98                 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
  99                 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
 100                 if (use_gpio) {
 101                         pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
 102                         pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp
 103                                         | 0x20);
 104                         pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp
 105                                         & ~0x20);
 106                 }
 107         } else {
 108                 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
 109         }
 110         /* Re-set the timer interval */
 111         mod_timer(&timer, jiffies + WDT_INTERVAL);
 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         mod_timer(&timer, jiffies + WDT_INTERVAL);
 150
 151         printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
 152 }
 153
 154 static void wdt_turnoff(void)
 155 {
 156         /* Stop the timer */
 157         del_timer_sync(&timer);
 158         wdt_change(WDT_DISABLE);
 159         printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
 160 }
 161
 162 static void wdt_keepalive(void)
 163 {
 164         /* user land ping */
 165         next_heartbeat = jiffies + (timeout * HZ);
 166 }
 167
 168 /*
 169  * /dev/watchdog handling
 170  */
 171
 172 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
 173 {
 174         /* See if we got the magic character 'V' and reload the timer */
 175         if(count) {
 176                 if (!nowayout) {
 177                         size_t ofs;
 178
 179                         /* note: just in case someone wrote the magic character
 180                          * five months ago... */
 181                         wdt_expect_close = 0;
 182
 183                         /* now scan */
 184                         for (ofs = 0; ofs != count; ofs++) {
 185                                 char c;
 186                                 if (get_user(c, buf+ofs))
 187                                         return -EFAULT;
 188                                 if (c == 'V')
 189                                         wdt_expect_close = 42;
 190                         }
 191                 }
 192                 /* someone wrote to us, we should restart timer */
 193                 wdt_keepalive();
 194         }
 195         return count;
 196 }
 197
 198 static int fop_open(struct inode * inode, struct file * file)
 199 {
 200         /* Just in case we're already talking to someone... */
 201         if(test_and_set_bit(0, &wdt_is_open))
 202                 return -EBUSY;
 203         /* Good, fire up the show */
 204         wdt_startup();
 205         return nonseekable_open(inode, file);
 206 }
 207
 208 static int fop_close(struct inode * inode, struct file * file)
 209 {
 210         if(wdt_expect_close == 42)
 211                 wdt_turnoff();
 212         else {
 213                 /* wim: shouldn't there be a: del_timer(&timer); */
 214                 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
 215         }
 216         clear_bit(0, &wdt_is_open);
 217         wdt_expect_close = 0;
 218         return 0;
 219 }
 220
 221 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 222 {
 223         void __user *argp = (void __user *)arg;
 224         int __user *p = argp;
 225         static struct watchdog_info ident =
 226         {
 227                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 228                 .firmware_version = 1,
 229                 .identity = "ALiM7101",
 230         };
 231
 232         switch(cmd)
 233         {
 234                 case WDIOC_GETSUPPORT:
 235                         return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
 236                 case WDIOC_GETSTATUS:
 237                 case WDIOC_GETBOOTSTATUS:
 238                         return put_user(0, p);
 239                 case WDIOC_KEEPALIVE:
 240                         wdt_keepalive();
 241                         return 0;
 242                 case WDIOC_SETOPTIONS:
 243                 {
 244                         int new_options, retval = -EINVAL;
 245
 246                         if(get_user(new_options, p))
 247                                 return -EFAULT;
 248
 249                         if(new_options & WDIOS_DISABLECARD) {
 250                                 wdt_turnoff();
 251                                 retval = 0;
 252                         }
 253
 254                         if(new_options & WDIOS_ENABLECARD) {
 255                                 wdt_startup();
 256                                 retval = 0;
 257                         }
 258
 259                         return retval;
 260                 }
 261                 case WDIOC_SETTIMEOUT:
 262                 {
 263                         int new_timeout;
 264
 265                         if(get_user(new_timeout, p))
 266                                 return -EFAULT;
 267
 268                         if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
 269                                 return -EINVAL;
 270
 271                         timeout = new_timeout;
 272                         wdt_keepalive();
 273                         /* Fall through */
 274                 }
 275                 case WDIOC_GETTIMEOUT:
 276                         return put_user(timeout, p);
 277                 default:
 278                         return -ENOTTY;
 279         }
 280 }
 281
 282 static const struct file_operations wdt_fops = {
 283         .owner=         THIS_MODULE,
 284         .llseek=        no_llseek,
 285         .write=         fop_write,
 286         .open=          fop_open,
 287         .release=       fop_close,
 288         .ioctl=         fop_ioctl,
 289 };
 290
 291 static struct miscdevice wdt_miscdev = {
 292         .minor=WATCHDOG_MINOR,
 293         .name="watchdog",
 294         .fops=&wdt_fops,
 295 };
 296
 297 /*
 298  *      Notifier for system down
 299  */
 300
 301 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
 302 {
 303         if (code==SYS_DOWN || code==SYS_HALT)
 304                 wdt_turnoff();
 305
 306         if (code==SYS_RESTART) {
 307                 /*
 308                  * Cobalt devices have no way of rebooting themselves other than
 309                  * getting the watchdog to pull reset, so we restart the watchdog on
 310                  * reboot with no heartbeat
 311                  */
 312                 wdt_change(WDT_ENABLE);
 313                 printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n");
 314         }
 315         return NOTIFY_DONE;
 316 }
 317
 318 /*
 319  *      The WDT needs to learn about soft shutdowns in order to
 320  *      turn the timebomb registers off.
 321  */
 322
 323 static struct notifier_block wdt_notifier=
 324 {
 325         .notifier_call = wdt_notify_sys,
 326 };
 327
 328 static void __exit alim7101_wdt_unload(void)
 329 {
 330         wdt_turnoff();
 331         /* Deregister */
 332         misc_deregister(&wdt_miscdev);
 333         unregister_reboot_notifier(&wdt_notifier);
 334         pci_dev_put(alim7101_pmu);
 335 }
 336
 337 static int __init alim7101_wdt_init(void)
 338 {
 339         int rc = -EBUSY;
 340         struct pci_dev *ali1543_south;
 341         char tmp;
 342
 343         printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
 344         alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
 345                 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_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
 355                 NULL);
 356         if (!ali1543_south) {
 357                 printk(KERN_INFO PFX "ALi 1543 South-Bridge not present - WDT not set\n");
 358                 goto err_out;
 359         }
 360         pci_read_config_byte(ali1543_south, 0x5e, &tmp);
 361         pci_dev_put(ali1543_south);
 362         if ((tmp & 0x1e) == 0x00) {
 363                 if (!use_gpio) {
 364                         printk(KERN_INFO PFX "Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
 365                         goto err_out;
 366                 }
 367                 nowayout = 1;
 368         } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
 369                 printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
 370                 goto err_out;
 371         }
 372
 373         if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
 374         {
 375                 timeout = WATCHDOG_TIMEOUT;
 376                 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
 377                         timeout);
 378         }
 379
 380         rc = misc_register(&wdt_miscdev);
 381         if (rc) {
 382                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 383                         wdt_miscdev.minor, rc);
 384                 goto err_out;
 385         }
 386
 387         rc = register_reboot_notifier(&wdt_notifier);
 388         if (rc) {
 389                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 390                         rc);
 391                 goto err_out_miscdev;
 392         }
 393
 394         if (nowayout) {
 395                 __module_get(THIS_MODULE);
 396         }
 397
 398         printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
 399                 timeout, nowayout);
 400         return 0;
 401
 402 err_out_miscdev:
 403         misc_deregister(&wdt_miscdev);
 404 err_out:
 405         pci_dev_put(alim7101_pmu);
 406         return rc;
 407 }
 408
 409 module_init(alim7101_wdt_init);
 410 module_exit(alim7101_wdt_unload);
 411
 412 static struct pci_device_id alim7101_pci_tbl[] __devinitdata = {
 413         { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
 414         { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
 415         { }
 416 };
 417
 418 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
 419
 420 MODULE_AUTHOR("Steve Hill");
 421 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
 422 MODULE_LICENSE("GPL");
 423 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);