drivers/watchdog/nv_tco.c

   1 /*
   2  *      nv_tco 0.01:    TCO timer driver for NV chipsets
   3  *
   4  *      (c) Copyright 2005 Google Inc., All Rights Reserved.
   5  *
   6  *      Based off i8xx_tco.c:
   7  *      (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
   8  *      Reserved.
   9  *                              http://www.kernelconcepts.de
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  *
  16  *      TCO timer driver for NV chipsets
  17  *      based on softdog.c by Alan Cox <alan@redhat.com>
  18  */
  19
  20 /*
  21  *      Includes, defines, variables, module parameters, ...
  22  */
  23
  24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  25
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/types.h>
  29 #include <linux/miscdevice.h>
  30 #include <linux/watchdog.h>
  31 #include <linux/init.h>
  32 #include <linux/fs.h>
  33 #include <linux/pci.h>
  34 #include <linux/ioport.h>
  35 #include <linux/jiffies.h>
  36 #include <linux/platform_device.h>
  37 #include <linux/uaccess.h>
  38 #include <linux/io.h>
  39
  40 #include "nv_tco.h"
  41
  42 /* Module and version information */
  43 #define TCO_VERSION "0.01"
  44 #define TCO_MODULE_NAME "NV_TCO"
  45 #define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
  46
  47 /* internal variables */
  48 static unsigned int tcobase;
  49 static DEFINE_SPINLOCK(tco_lock);       /* Guards the hardware */
  50 static unsigned long timer_alive;
  51 static char tco_expect_close;
  52 static struct pci_dev *tco_pci;
  53
  54 /* the watchdog platform device */
  55 static struct platform_device *nv_tco_platform_device;
  56
  57 /* module parameters */
  58 #define WATCHDOG_HEARTBEAT 30   /* 30 sec default heartbeat (2<heartbeat<39) */
  59 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  60 module_param(heartbeat, int, 0);
  61 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
  62                             "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  63
  64 static bool nowayout = WATCHDOG_NOWAYOUT;
  65 module_param(nowayout, bool, 0);
  66 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
  67                 " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  68
  69 /*
  70  * Some TCO specific functions
  71  */
  72 static inline unsigned char seconds_to_ticks(int seconds)
  73 {
  74         /* the internal timer is stored as ticks which decrement
  75          * every 0.6 seconds */
  76         return (seconds * 10) / 6;
  77 }
  78
  79 static void tco_timer_start(void)
  80 {
  81         u32 val;
  82         unsigned long flags;
  83
  84         spin_lock_irqsave(&tco_lock, flags);
  85         val = inl(TCO_CNT(tcobase));
  86         val &= ~TCO_CNT_TCOHALT;
  87         outl(val, TCO_CNT(tcobase));
  88         spin_unlock_irqrestore(&tco_lock, flags);
  89 }
  90
  91 static void tco_timer_stop(void)
  92 {
  93         u32 val;
  94         unsigned long flags;
  95
  96         spin_lock_irqsave(&tco_lock, flags);
  97         val = inl(TCO_CNT(tcobase));
  98         val |= TCO_CNT_TCOHALT;
  99         outl(val, TCO_CNT(tcobase));
 100         spin_unlock_irqrestore(&tco_lock, flags);
 101 }
 102
 103 static void tco_timer_keepalive(void)
 104 {
 105         unsigned long flags;
 106
 107         spin_lock_irqsave(&tco_lock, flags);
 108         outb(0x01, TCO_RLD(tcobase));
 109         spin_unlock_irqrestore(&tco_lock, flags);
 110 }
 111
 112 static int tco_timer_set_heartbeat(int t)
 113 {
 114         int ret = 0;
 115         unsigned char tmrval;
 116         unsigned long flags;
 117         u8 val;
 118
 119         /*
 120          * note seconds_to_ticks(t) > t, so if t > 0x3f, so is
 121          * tmrval=seconds_to_ticks(t).  Check that the count in seconds isn't
 122          * out of range on it's own (to avoid overflow in tmrval).
 123          */
 124         if (t < 0 || t > 0x3f)
 125                 return -EINVAL;
 126         tmrval = seconds_to_ticks(t);
 127
 128         /* "Values of 0h-3h are ignored and should not be attempted" */
 129         if (tmrval > 0x3f || tmrval < 0x04)
 130                 return -EINVAL;
 131
 132         /* Write new heartbeat to watchdog */
 133         spin_lock_irqsave(&tco_lock, flags);
 134         val = inb(TCO_TMR(tcobase));
 135         val &= 0xc0;
 136         val |= tmrval;
 137         outb(val, TCO_TMR(tcobase));
 138         val = inb(TCO_TMR(tcobase));
 139
 140         if ((val & 0x3f) != tmrval)
 141                 ret = -EINVAL;
 142         spin_unlock_irqrestore(&tco_lock, flags);
 143
 144         if (ret)
 145                 return ret;
 146
 147         heartbeat = t;
 148         return 0;
 149 }
 150
 151 /*
 152  *      /dev/watchdog handling
 153  */
 154
 155 static int nv_tco_open(struct inode *inode, struct file *file)
 156 {
 157         /* /dev/watchdog can only be opened once */
 158         if (test_and_set_bit(0, &timer_alive))
 159                 return -EBUSY;
 160
 161         /* Reload and activate timer */
 162         tco_timer_keepalive();
 163         tco_timer_start();
 164         return nonseekable_open(inode, file);
 165 }
 166
 167 static int nv_tco_release(struct inode *inode, struct file *file)
 168 {
 169         /* Shut off the timer */
 170         if (tco_expect_close == 42) {
 171                 tco_timer_stop();
 172         } else {
 173                 pr_crit("Unexpected close, not stopping watchdog!\n");
 174                 tco_timer_keepalive();
 175         }
 176         clear_bit(0, &timer_alive);
 177         tco_expect_close = 0;
 178         return 0;
 179 }
 180
 181 static ssize_t nv_tco_write(struct file *file, const char __user *data,
 182                             size_t len, loff_t *ppos)
 183 {
 184         /* See if we got the magic character 'V' and reload the timer */
 185         if (len) {
 186                 if (!nowayout) {
 187                         size_t i;
 188
 189                         /*
 190                          * note: just in case someone wrote the magic character
 191                          * five months ago...
 192                          */
 193                         tco_expect_close = 0;
 194
 195                         /*
 196                          * scan to see whether or not we got the magic
 197                          * character
 198                          */
 199                         for (i = 0; i != len; i++) {
 200                                 char c;
 201                                 if (get_user(c, data + i))
 202                                         return -EFAULT;
 203                                 if (c == 'V')
 204                                         tco_expect_close = 42;
 205                         }
 206                 }
 207
 208                 /* someone wrote to us, we should reload the timer */
 209                 tco_timer_keepalive();
 210         }
 211         return len;
 212 }
 213
 214 static long nv_tco_ioctl(struct file *file, unsigned int cmd,
 215                          unsigned long arg)
 216 {
 217         int new_options, retval = -EINVAL;
 218         int new_heartbeat;
 219         void __user *argp = (void __user *)arg;
 220         int __user *p = argp;
 221         static const struct watchdog_info ident = {
 222                 .options =              WDIOF_SETTIMEOUT |
 223                                         WDIOF_KEEPALIVEPING |
 224                                         WDIOF_MAGICCLOSE,
 225                 .firmware_version =     0,
 226                 .identity =             TCO_MODULE_NAME,
 227         };
 228
 229         switch (cmd) {
 230         case WDIOC_GETSUPPORT:
 231                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 232         case WDIOC_GETSTATUS:
 233         case WDIOC_GETBOOTSTATUS:
 234                 return put_user(0, p);
 235         case WDIOC_SETOPTIONS:
 236                 if (get_user(new_options, p))
 237                         return -EFAULT;
 238                 if (new_options & WDIOS_DISABLECARD) {
 239                         tco_timer_stop();
 240                         retval = 0;
 241                 }
 242                 if (new_options & WDIOS_ENABLECARD) {
 243                         tco_timer_keepalive();
 244                         tco_timer_start();
 245                         retval = 0;
 246                 }
 247                 return retval;
 248         case WDIOC_KEEPALIVE:
 249                 tco_timer_keepalive();
 250                 return 0;
 251         case WDIOC_SETTIMEOUT:
 252                 if (get_user(new_heartbeat, p))
 253                         return -EFAULT;
 254                 if (tco_timer_set_heartbeat(new_heartbeat))
 255                         return -EINVAL;
 256                 tco_timer_keepalive();
 257                 /* Fall through */
 258         case WDIOC_GETTIMEOUT:
 259                 return put_user(heartbeat, p);
 260         default:
 261                 return -ENOTTY;
 262         }
 263 }
 264
 265 /*
 266  *      Kernel Interfaces
 267  */
 268
 269 static const struct file_operations nv_tco_fops = {
 270         .owner =                THIS_MODULE,
 271         .llseek =               no_llseek,
 272         .write =                nv_tco_write,
 273         .unlocked_ioctl =       nv_tco_ioctl,
 274         .open =                 nv_tco_open,
 275         .release =              nv_tco_release,
 276 };
 277
 278 static struct miscdevice nv_tco_miscdev = {
 279         .minor =        WATCHDOG_MINOR,
 280         .name =         "watchdog",
 281         .fops =         &nv_tco_fops,
 282 };
 283
 284 /*
 285  * Data for PCI driver interface
 286  *
 287  * This data only exists for exporting the supported
 288  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 289  * register a pci_driver, because someone else might one day
 290  * want to register another driver on the same PCI id.
 291  */
 292 static DEFINE_PCI_DEVICE_TABLE(tco_pci_tbl) = {
 293         { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
 294           PCI_ANY_ID, PCI_ANY_ID, },
 295         { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
 296           PCI_ANY_ID, PCI_ANY_ID, },
 297         { 0, },                 /* End of list */
 298 };
 299 MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
 300
 301 /*
 302  *      Init & exit routines
 303  */
 304
 305 static unsigned char nv_tco_getdevice(void)
 306 {
 307         struct pci_dev *dev = NULL;
 308         u32 val;
 309
 310         /* Find the PCI device */
 311         for_each_pci_dev(dev) {
 312                 if (pci_match_id(tco_pci_tbl, dev) != NULL) {
 313                         tco_pci = dev;
 314                         break;
 315                 }
 316         }
 317
 318         if (!tco_pci)
 319                 return 0;
 320
 321         /* Find the base io port */
 322         pci_read_config_dword(tco_pci, 0x64, &val);
 323         val &= 0xffff;
 324         if (val == 0x0001 || val == 0x0000) {
 325                 /* Something is wrong here, bar isn't setup */
 326                 pr_err("failed to get tcobase address\n");
 327                 return 0;
 328         }
 329         val &= 0xff00;
 330         tcobase = val + 0x40;
 331
 332         if (!request_region(tcobase, 0x10, "NV TCO")) {
 333                 pr_err("I/O address 0x%04x already in use\n", tcobase);
 334                 return 0;
 335         }
 336
 337         /* Set a reasonable heartbeat before we stop the timer */
 338         tco_timer_set_heartbeat(30);
 339
 340         /*
 341          * Stop the TCO before we change anything so we don't race with
 342          * a zeroed timer.
 343          */
 344         tco_timer_keepalive();
 345         tco_timer_stop();
 346
 347         /* Disable SMI caused by TCO */
 348         if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
 349                 pr_err("I/O address 0x%04x already in use\n",
 350                        MCP51_SMI_EN(tcobase));
 351                 goto out;
 352         }
 353         val = inl(MCP51_SMI_EN(tcobase));
 354         val &= ~MCP51_SMI_EN_TCO;
 355         outl(val, MCP51_SMI_EN(tcobase));
 356         val = inl(MCP51_SMI_EN(tcobase));
 357         release_region(MCP51_SMI_EN(tcobase), 4);
 358         if (val & MCP51_SMI_EN_TCO) {
 359                 pr_err("Could not disable SMI caused by TCO\n");
 360                 goto out;
 361         }
 362
 363         /* Check chipset's NO_REBOOT bit */
 364         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 365         val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 366         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 367         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 368         if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
 369                 pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
 370                 goto out;
 371         }
 372
 373         return 1;
 374 out:
 375         release_region(tcobase, 0x10);
 376         return 0;
 377 }
 378
 379 static int nv_tco_init(struct platform_device *dev)
 380 {
 381         int ret;
 382
 383         /* Check whether or not the hardware watchdog is there */
 384         if (!nv_tco_getdevice())
 385                 return -ENODEV;
 386
 387         /* Check to see if last reboot was due to watchdog timeout */
 388         pr_info("Watchdog reboot %sdetected\n",
 389                 inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");
 390
 391         /* Clear out the old status */
 392         outl(TCO_STS_RESET, TCO_STS(tcobase));
 393
 394         /*
 395          * Check that the heartbeat value is within it's range.
 396          * If not, reset to the default.
 397          */
 398         if (tco_timer_set_heartbeat(heartbeat)) {
 399                 heartbeat = WATCHDOG_HEARTBEAT;
 400                 tco_timer_set_heartbeat(heartbeat);
 401                 pr_info("heartbeat value must be 2<heartbeat<39, using %d\n",
 402                         heartbeat);
 403         }
 404
 405         ret = misc_register(&nv_tco_miscdev);
 406         if (ret != 0) {
 407                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 408                        WATCHDOG_MINOR, ret);
 409                 goto unreg_region;
 410         }
 411
 412         clear_bit(0, &timer_alive);
 413
 414         tco_timer_stop();
 415
 416         pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
 417                 tcobase, heartbeat, nowayout);
 418
 419         return 0;
 420
 421 unreg_region:
 422         release_region(tcobase, 0x10);
 423         return ret;
 424 }
 425
 426 static void nv_tco_cleanup(void)
 427 {
 428         u32 val;
 429
 430         /* Stop the timer before we leave */
 431         if (!nowayout)
 432                 tco_timer_stop();
 433
 434         /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
 435         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 436         val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 437         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 438         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 439         if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
 440                 pr_crit("Couldn't unset REBOOT bit.  Machine may soon reset\n");
 441         }
 442
 443         /* Deregister */
 444         misc_deregister(&nv_tco_miscdev);
 445         release_region(tcobase, 0x10);
 446 }
 447
 448 static int nv_tco_remove(struct platform_device *dev)
 449 {
 450         if (tcobase)
 451                 nv_tco_cleanup();
 452
 453         return 0;
 454 }
 455
 456 static void nv_tco_shutdown(struct platform_device *dev)
 457 {
 458         u32 val;
 459
 460         tco_timer_stop();
 461
 462         /* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
 463          * unset during shutdown. */
 464         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 465         val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 466         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 467 }
 468
 469 static struct platform_driver nv_tco_driver = {
 470         .probe          = nv_tco_init,
 471         .remove         = nv_tco_remove,
 472         .shutdown       = nv_tco_shutdown,
 473         .driver         = {
 474                 .owner  = THIS_MODULE,
 475                 .name   = TCO_MODULE_NAME,
 476         },
 477 };
 478
 479 static int __init nv_tco_init_module(void)
 480 {
 481         int err;
 482
 483         pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
 484
 485         err = platform_driver_register(&nv_tco_driver);
 486         if (err)
 487                 return err;
 488
 489         nv_tco_platform_device = platform_device_register_simple(
 490                                         TCO_MODULE_NAME, -1, NULL, 0);
 491         if (IS_ERR(nv_tco_platform_device)) {
 492                 err = PTR_ERR(nv_tco_platform_device);
 493                 goto unreg_platform_driver;
 494         }
 495
 496         return 0;
 497
 498 unreg_platform_driver:
 499         platform_driver_unregister(&nv_tco_driver);
 500         return err;
 501 }
 502
 503 static void __exit nv_tco_cleanup_module(void)
 504 {
 505         platform_device_unregister(nv_tco_platform_device);
 506         platform_driver_unregister(&nv_tco_driver);
 507         pr_info("NV TCO Watchdog Module Unloaded\n");
 508 }
 509
 510 module_init(nv_tco_init_module);
 511 module_exit(nv_tco_cleanup_module);
 512
 513 MODULE_AUTHOR("Mike Waychison");
 514 MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
 515 MODULE_LICENSE("GPL");
 516 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);