drivers/watchdog/alim1535_wdt.c

   1 /*
   2  *      Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License
   6  *      as published by the Free Software Foundation; either version
   7  *      2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/moduleparam.h>
  12 #include <linux/types.h>
  13 #include <linux/miscdevice.h>
  14 #include <linux/watchdog.h>
  15 #include <linux/ioport.h>
  16 #include <linux/notifier.h>
  17 #include <linux/reboot.h>
  18 #include <linux/init.h>
  19 #include <linux/fs.h>
  20 #include <linux/pci.h>
  21
  22 #include <linux/uaccess.h>
  23 #include <linux/io.h>
  24
  25 #define WATCHDOG_NAME "ALi_M1535"
  26 #define PFX WATCHDOG_NAME ": "
  27 #define WATCHDOG_TIMEOUT 60     /* 60 sec default timeout */
  28
  29 /* internal variables */
  30 static unsigned long ali_is_open;
  31 static char ali_expect_release;
  32 static struct pci_dev *ali_pci;
  33 static u32 ali_timeout_bits;            /* stores the computed timeout */
  34 static DEFINE_SPINLOCK(ali_lock);       /* Guards the hardware */
  35
  36 /* module parameters */
  37 static int timeout = WATCHDOG_TIMEOUT;
  38 module_param(timeout, int, 0);
  39 MODULE_PARM_DESC(timeout,
  40                 "Watchdog timeout in seconds. (0 < timeout < 18000, default="
  41                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  42
  43 static int nowayout = WATCHDOG_NOWAYOUT;
  44 module_param(nowayout, int, 0);
  45 MODULE_PARM_DESC(nowayout,
  46                 "Watchdog cannot be stopped once started (default="
  47                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  48
  49 /*
  50  *      ali_start       -       start watchdog countdown
  51  *
  52  *      Starts the timer running providing the timer has a counter
  53  *      configuration set.
  54  */
  55
  56 static void ali_start(void)
  57 {
  58         u32 val;
  59
  60         spin_lock(&ali_lock);
  61
  62         pci_read_config_dword(ali_pci, 0xCC, &val);
  63         val &= ~0x3F;   /* Mask count */
  64         val |= (1<<25) | ali_timeout_bits;
  65         pci_write_config_dword(ali_pci, 0xCC, val);
  66
  67         spin_unlock(&ali_lock);
  68 }
  69
  70 /*
  71  *      ali_stop        -       stop the timer countdown
  72  *
  73  *      Stop the ALi watchdog countdown
  74  */
  75
  76 static void ali_stop(void)
  77 {
  78         u32 val;
  79
  80         spin_lock(&ali_lock);
  81
  82         pci_read_config_dword(ali_pci, 0xCC, &val);
  83         val &= ~0x3F;   /* Mask count to zero (disabled) */
  84         val &= ~(1<<25);/* and for safety mask the reset enable */
  85         pci_write_config_dword(ali_pci, 0xCC, val);
  86
  87         spin_unlock(&ali_lock);
  88 }
  89
  90 /*
  91  *      ali_keepalive   -       send a keepalive to the watchdog
  92  *
  93  *      Send a keepalive to the timer (actually we restart the timer).
  94  */
  95
  96 static void ali_keepalive(void)
  97 {
  98         ali_start();
  99 }
 100
 101 /*
 102  *      ali_settimer    -       compute the timer reload value
 103  *      @t: time in seconds
 104  *
 105  *      Computes the timeout values needed
 106  */
 107
 108 static int ali_settimer(int t)
 109 {
 110         if (t < 0)
 111                 return -EINVAL;
 112         else if (t < 60)
 113                 ali_timeout_bits = t|(1<<6);
 114         else if (t < 3600)
 115                 ali_timeout_bits = (t/60)|(1<<7);
 116         else if (t < 18000)
 117                 ali_timeout_bits = (t/300)|(1<<6)|(1<<7);
 118         else
 119                 return -EINVAL;
 120
 121         timeout = t;
 122         return 0;
 123 }
 124
 125 /*
 126  *      /dev/watchdog handling
 127  */
 128
 129 /*
 130  *      ali_write       -       writes to ALi watchdog
 131  *      @file: file from VFS
 132  *      @data: user address of data
 133  *      @len: length of data
 134  *      @ppos: pointer to the file offset
 135  *
 136  *      Handle a write to the ALi watchdog. Writing to the file pings
 137  *      the watchdog and resets it. Writing the magic 'V' sequence allows
 138  *      the next close to turn off the watchdog.
 139  */
 140
 141 static ssize_t ali_write(struct file *file, const char __user *data,
 142                               size_t len, loff_t *ppos)
 143 {
 144         /* See if we got the magic character 'V' and reload the timer */
 145         if (len) {
 146                 if (!nowayout) {
 147                         size_t i;
 148
 149                         /* note: just in case someone wrote the
 150                            magic character five months ago... */
 151                         ali_expect_release = 0;
 152
 153                         /* scan to see whether or not we got
 154                            the magic character */
 155                         for (i = 0; i != len; i++) {
 156                                 char c;
 157                                 if (get_user(c, data+i))
 158                                         return -EFAULT;
 159                                 if (c == 'V')
 160                                         ali_expect_release = 42;
 161                         }
 162                 }
 163
 164                 /* someone wrote to us, we should reload the timer */
 165                 ali_start();
 166         }
 167         return len;
 168 }
 169
 170 /*
 171  *      ali_ioctl       -       handle watchdog ioctls
 172  *      @file: VFS file pointer
 173  *      @cmd: ioctl number
 174  *      @arg: arguments to the ioctl
 175  *
 176  *      Handle the watchdog ioctls supported by the ALi driver. Really
 177  *      we want an extension to enable irq ack monitoring and the like
 178  */
 179
 180 static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 181 {
 182         void __user *argp = (void __user *)arg;
 183         int __user *p = argp;
 184         static struct watchdog_info ident = {
 185                 .options =              WDIOF_KEEPALIVEPING |
 186                                         WDIOF_SETTIMEOUT |
 187                                         WDIOF_MAGICCLOSE,
 188                 .firmware_version =     0,
 189                 .identity =             "ALi M1535 WatchDog Timer",
 190         };
 191
 192         switch (cmd) {
 193         case WDIOC_GETSUPPORT:
 194                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 195
 196         case WDIOC_GETSTATUS:
 197         case WDIOC_GETBOOTSTATUS:
 198                 return put_user(0, p);
 199         case WDIOC_KEEPALIVE:
 200                 ali_keepalive();
 201                 return 0;
 202         case WDIOC_SETOPTIONS:
 203         {
 204                 int new_options, retval = -EINVAL;
 205
 206                 if (get_user(new_options, p))
 207                         return -EFAULT;
 208                 if (new_options & WDIOS_DISABLECARD) {
 209                         ali_stop();
 210                         retval = 0;
 211                 }
 212                 if (new_options & WDIOS_ENABLECARD) {
 213                         ali_start();
 214                         retval = 0;
 215                 }
 216                 return retval;
 217         }
 218         case WDIOC_SETTIMEOUT:
 219         {
 220                 int new_timeout;
 221                 if (get_user(new_timeout, p))
 222                         return -EFAULT;
 223                 if (ali_settimer(new_timeout))
 224                         return -EINVAL;
 225                 ali_keepalive();
 226                 /* Fall */
 227         }
 228         case WDIOC_GETTIMEOUT:
 229                 return put_user(timeout, p);
 230         default:
 231                 return -ENOTTY;
 232         }
 233 }
 234
 235 /*
 236  *      ali_open        -       handle open of ali watchdog
 237  *      @inode: inode from VFS
 238  *      @file: file from VFS
 239  *
 240  *      Open the ALi watchdog device. Ensure only one person opens it
 241  *      at a time. Also start the watchdog running.
 242  */
 243
 244 static int ali_open(struct inode *inode, struct file *file)
 245 {
 246         /* /dev/watchdog can only be opened once */
 247         if (test_and_set_bit(0, &ali_is_open))
 248                 return -EBUSY;
 249
 250         /* Activate */
 251         ali_start();
 252         return nonseekable_open(inode, file);
 253 }
 254
 255 /*
 256  *      ali_release     -       close an ALi watchdog
 257  *      @inode: inode from VFS
 258  *      @file: file from VFS
 259  *
 260  *      Close the ALi watchdog device. Actual shutdown of the timer
 261  *      only occurs if the magic sequence has been set.
 262  */
 263
 264 static int ali_release(struct inode *inode, struct file *file)
 265 {
 266         /*
 267          *      Shut off the timer.
 268          */
 269         if (ali_expect_release == 42)
 270                 ali_stop();
 271         else {
 272                 printk(KERN_CRIT PFX
 273                                 "Unexpected close, not stopping watchdog!\n");
 274                 ali_keepalive();
 275         }
 276         clear_bit(0, &ali_is_open);
 277         ali_expect_release = 0;
 278         return 0;
 279 }
 280
 281 /*
 282  *      ali_notify_sys  -       System down notifier
 283  *
 284  *      Notifier for system down
 285  */
 286
 287
 288 static int ali_notify_sys(struct notifier_block *this,
 289                                         unsigned long code, void *unused)
 290 {
 291         if (code == SYS_DOWN || code == SYS_HALT)
 292                 ali_stop();             /* Turn the WDT off */
 293         return NOTIFY_DONE;
 294 }
 295
 296 /*
 297  *      Data for PCI driver interface
 298  *
 299  *      This data only exists for exporting the supported
 300  *      PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 301  *      register a pci_driver, because someone else might one day
 302  *      want to register another driver on the same PCI id.
 303  */
 304
 305 static struct pci_device_id ali_pci_tbl[] = {
 306         { PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,},
 307         { PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,},
 308         { 0, },
 309 };
 310 MODULE_DEVICE_TABLE(pci, ali_pci_tbl);
 311
 312 /*
 313  *      ali_find_watchdog       -       find a 1535 and 7101
 314  *
 315  *      Scans the PCI hardware for a 1535 series bridge and matching 7101
 316  *      watchdog device. This may be overtight but it is better to be safe
 317  */
 318
 319 static int __init ali_find_watchdog(void)
 320 {
 321         struct pci_dev *pdev;
 322         u32 wdog;
 323
 324         /* Check for a 1533/1535 series bridge */
 325         pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL);
 326         if (pdev == NULL)
 327                 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL);
 328         if (pdev == NULL)
 329                 return -ENODEV;
 330         pci_dev_put(pdev);
 331
 332         /* Check for the a 7101 PMU */
 333         pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL);
 334         if (pdev == NULL)
 335                 return -ENODEV;
 336
 337         if (pci_enable_device(pdev)) {
 338                 pci_dev_put(pdev);
 339                 return -EIO;
 340         }
 341
 342         ali_pci = pdev;
 343
 344         /*
 345          *      Initialize the timer bits
 346          */
 347         pci_read_config_dword(pdev, 0xCC, &wdog);
 348
 349         /* Timer bits */
 350         wdog &= ~0x3F;
 351         /* Issued events */
 352         wdog &= ~((1<<27)|(1<<26)|(1<<25)|(1<<24));
 353         /* No monitor bits */
 354         wdog &= ~((1<<16)|(1<<13)|(1<<12)|(1<<11)|(1<<10)|(1<<9));
 355
 356         pci_write_config_dword(pdev, 0xCC, wdog);
 357
 358         return 0;
 359 }
 360
 361 /*
 362  *      Kernel Interfaces
 363  */
 364
 365 static const struct file_operations ali_fops = {
 366         .owner          =       THIS_MODULE,
 367         .llseek         =       no_llseek,
 368         .write          =       ali_write,
 369         .unlocked_ioctl =       ali_ioctl,
 370         .open           =       ali_open,
 371         .release        =       ali_release,
 372 };
 373
 374 static struct miscdevice ali_miscdev = {
 375         .minor =        WATCHDOG_MINOR,
 376         .name =         "watchdog",
 377         .fops =         &ali_fops,
 378 };
 379
 380 static struct notifier_block ali_notifier = {
 381         .notifier_call =        ali_notify_sys,
 382 };
 383
 384 /*
 385  *      watchdog_init   -       module initialiser
 386  *
 387  *      Scan for a suitable watchdog and if so initialize it. Return an error
 388  *      if we cannot, the error causes the module to unload
 389  */
 390
 391 static int __init watchdog_init(void)
 392 {
 393         int ret;
 394
 395         /* Check whether or not the hardware watchdog is there */
 396         if (ali_find_watchdog() != 0)
 397                 return -ENODEV;
 398
 399         /* Check that the timeout value is within it's range;
 400            if not reset to the default */
 401         if (timeout < 1 || timeout >= 18000) {
 402                 timeout = WATCHDOG_TIMEOUT;
 403                 printk(KERN_INFO PFX
 404                      "timeout value must be 0 < timeout < 18000, using %d\n",
 405                                                         timeout);
 406         }
 407
 408         /* Calculate the watchdog's timeout */
 409         ali_settimer(timeout);
 410
 411         ret = register_reboot_notifier(&ali_notifier);
 412         if (ret != 0) {
 413                 printk(KERN_ERR PFX
 414                         "cannot register reboot notifier (err=%d)\n", ret);
 415                 goto out;
 416         }
 417
 418         ret = misc_register(&ali_miscdev);
 419         if (ret != 0) {
 420                 printk(KERN_ERR PFX
 421                         "cannot register miscdev on minor=%d (err=%d)\n",
 422                                                 WATCHDOG_MINOR, ret);
 423                 goto unreg_reboot;
 424         }
 425
 426         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 427                 timeout, nowayout);
 428
 429 out:
 430         return ret;
 431 unreg_reboot:
 432         unregister_reboot_notifier(&ali_notifier);
 433         goto out;
 434 }
 435
 436 /*
 437  *      watchdog_exit   -       module de-initialiser
 438  *
 439  *      Called while unloading a successfully installed watchdog module.
 440  */
 441
 442 static void __exit watchdog_exit(void)
 443 {
 444         /* Stop the timer before we leave */
 445         ali_stop();
 446
 447         /* Deregister */
 448         misc_deregister(&ali_miscdev);
 449         unregister_reboot_notifier(&ali_notifier);
 450         pci_dev_put(ali_pci);
 451 }
 452
 453 module_init(watchdog_init);
 454 module_exit(watchdog_exit);
 455
 456 MODULE_AUTHOR("Alan Cox");
 457 MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");
 458 MODULE_LICENSE("GPL");
 459 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);