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="
  81                  __stringify(CONFIG_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         timer.expires = jiffies + WDT_INTERVAL;
 112         add_timer(&timer);
 113 }
 114
 115 /*
 116  * Utility routines
 117  */
 118
 119 static void wdt_change(int writeval)
 120 {
 121         char    tmp;
 122
 123         pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
 124         if (writeval == WDT_ENABLE) {
 125                 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
 126                 if (use_gpio) {
 127                         pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
 128                         pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp & ~0x20);
 129                 }
 130
 131         } else {
 132                 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
 133                 if (use_gpio) {
 134                         pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
 135                         pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp | 0x20);
 136                 }
 137         }
 138 }
 139
 140 static void wdt_startup(void)
 141 {
 142         next_heartbeat = jiffies + (timeout * HZ);
 143
 144         /* We must enable before we kick off the timer in case the timer
 145            occurs as we ping it */
 146
 147         wdt_change(WDT_ENABLE);
 148
 149         /* Start the timer */
 150         timer.expires = jiffies + WDT_INTERVAL;
 151         add_timer(&timer);
 152
 153
 154         printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
 155 }
 156
 157 static void wdt_turnoff(void)
 158 {
 159         /* Stop the timer */
 160         del_timer_sync(&timer);
 161         wdt_change(WDT_DISABLE);
 162         printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
 163 }
 164
 165 static void wdt_keepalive(void)
 166 {
 167         /* user land ping */
 168         next_heartbeat = jiffies + (timeout * HZ);
 169 }
 170
 171 /*
 172  * /dev/watchdog handling
 173  */
 174
 175 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
 176 {
 177         /* See if we got the magic character 'V' and reload the timer */
 178         if(count) {
 179                 if (!nowayout) {
 180                         size_t ofs;
 181
 182                         /* note: just in case someone wrote the magic character
 183                          * five months ago... */
 184                         wdt_expect_close = 0;
 185
 186                         /* now scan */
 187                         for (ofs = 0; ofs != count; ofs++) {
 188                                 char c;
 189                                 if (get_user(c, buf+ofs))
 190                                         return -EFAULT;
 191                                 if (c == 'V')
 192                                         wdt_expect_close = 42;
 193                         }
 194                 }
 195                 /* someone wrote to us, we should restart timer */
 196                 wdt_keepalive();
 197         }
 198         return count;
 199 }
 200
 201 static int fop_open(struct inode * inode, struct file * file)
 202 {
 203         /* Just in case we're already talking to someone... */
 204         if(test_and_set_bit(0, &wdt_is_open))
 205                 return -EBUSY;
 206         /* Good, fire up the show */
 207         wdt_startup();
 208         return nonseekable_open(inode, file);
 209 }
 210
 211 static int fop_close(struct inode * inode, struct file * file)
 212 {
 213         if(wdt_expect_close == 42)
 214                 wdt_turnoff();
 215         else {
 216                 /* wim: shouldn't there be a: del_timer(&timer); */
 217                 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
 218         }
 219         clear_bit(0, &wdt_is_open);
 220         wdt_expect_close = 0;
 221         return 0;
 222 }
 223
 224 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 225 {
 226         void __user *argp = (void __user *)arg;
 227         int __user *p = argp;
 228         static struct watchdog_info ident =
 229         {
 230                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 231                 .firmware_version = 1,
 232                 .identity = "ALiM7101",
 233         };
 234
 235         switch(cmd)
 236         {
 237                 case WDIOC_GETSUPPORT:
 238                         return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
 239                 case WDIOC_GETSTATUS:
 240                 case WDIOC_GETBOOTSTATUS:
 241                         return put_user(0, p);
 242                 case WDIOC_KEEPALIVE:
 243                         wdt_keepalive();
 244                         return 0;
 245                 case WDIOC_SETOPTIONS:
 246                 {
 247                         int new_options, retval = -EINVAL;
 248
 249                         if(get_user(new_options, p))
 250                                 return -EFAULT;
 251
 252                         if(new_options & WDIOS_DISABLECARD) {
 253                                 wdt_turnoff();
 254                                 retval = 0;
 255                         }
 256
 257                         if(new_options & WDIOS_ENABLECARD) {
 258                                 wdt_startup();
 259                                 retval = 0;
 260                         }
 261
 262                         return retval;
 263                 }
 264                 case WDIOC_SETTIMEOUT:
 265                 {
 266                         int new_timeout;
 267
 268                         if(get_user(new_timeout, p))
 269                                 return -EFAULT;
 270
 271                         if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
 272                                 return -EINVAL;
 273
 274                         timeout = new_timeout;
 275                         wdt_keepalive();
 276                         /* Fall through */
 277                 }
 278                 case WDIOC_GETTIMEOUT:
 279                         return put_user(timeout, p);
 280                 default:
 281                         return -ENOTTY;
 282         }
 283 }
 284
 285 static const struct file_operations wdt_fops = {
 286         .owner=         THIS_MODULE,
 287         .llseek=        no_llseek,
 288         .write=         fop_write,
 289         .open=          fop_open,
 290         .release=       fop_close,
 291         .ioctl=         fop_ioctl,
 292 };
 293
 294 static struct miscdevice wdt_miscdev = {
 295         .minor=WATCHDOG_MINOR,
 296         .name="watchdog",
 297         .fops=&wdt_fops,
 298 };
 299
 300 /*
 301  *      Notifier for system down
 302  */
 303
 304 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
 305 {
 306         if (code==SYS_DOWN || code==SYS_HALT)
 307                 wdt_turnoff();
 308
 309         if (code==SYS_RESTART) {
 310                 /*
 311                  * Cobalt devices have no way of rebooting themselves other than
 312                  * getting the watchdog to pull reset, so we restart the watchdog on
 313                  * reboot with no heartbeat
 314                  */
 315                 wdt_change(WDT_ENABLE);
 316                 printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n");
 317         }
 318         return NOTIFY_DONE;
 319 }
 320
 321 /*
 322  *      The WDT needs to learn about soft shutdowns in order to
 323  *      turn the timebomb registers off.
 324  */
 325
 326 static struct notifier_block wdt_notifier=
 327 {
 328         .notifier_call = wdt_notify_sys,
 329 };
 330
 331 static void __exit alim7101_wdt_unload(void)
 332 {
 333         wdt_turnoff();
 334         /* Deregister */
 335         misc_deregister(&wdt_miscdev);
 336         unregister_reboot_notifier(&wdt_notifier);
 337         pci_dev_put(alim7101_pmu);
 338 }
 339
 340 static int __init alim7101_wdt_init(void)
 341 {
 342         int rc = -EBUSY;
 343         struct pci_dev *ali1543_south;
 344         char tmp;
 345
 346         printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
 347         alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
 348                 NULL);
 349         if (!alim7101_pmu) {
 350                 printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n");
 351                 return -EBUSY;
 352         }
 353
 354         /* Set the WDT in the PMU to 1 second */
 355         pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
 356
 357         ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
 358                 NULL);
 359         if (!ali1543_south) {
 360                 printk(KERN_INFO PFX "ALi 1543 South-Bridge not present - WDT not set\n");
 361                 goto err_out;
 362         }
 363         pci_read_config_byte(ali1543_south, 0x5e, &tmp);
 364         pci_dev_put(ali1543_south);
 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                         goto err_out;
 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                 goto err_out;
 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         pci_dev_put(alim7101_pmu);
 413         return rc;
 414 }
 415
 416 module_init(alim7101_wdt_init);
 417 module_exit(alim7101_wdt_unload);
 418
 419 static struct pci_device_id alim7101_pci_tbl[] __devinitdata = {
 420         { PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
 421           PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
 422         { PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
 423           PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
 424         { }
 425 };
 426
 427 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
 428
 429 MODULE_AUTHOR("Steve Hill");
 430 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
 431 MODULE_LICENSE("GPL");
 432 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);