drivers/watchdog/nv_tco.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      nv_tco 0.01:    TCO timer driver for NV chipsets
   4  *
   5  *      (c) Copyright 2005 Google Inc., All Rights Reserved.
   6  *
   7  *      Based off i8xx_tco.c:
   8  *      (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
   9  *      Reserved.
  10  *                              https://www.kernelconcepts.de
  11  *
  12  *      TCO timer driver for NV chipsets
  13  *      based on softdog.c by Alan Cox <alan@redhat.com>
  14  */
  15
  16 /*
  17  *      Includes, defines, variables, module parameters, ...
  18  */
  19
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/types.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/watchdog.h>
  27 #include <linux/init.h>
  28 #include <linux/fs.h>
  29 #include <linux/pci.h>
  30 #include <linux/ioport.h>
  31 #include <linux/jiffies.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/uaccess.h>
  34 #include <linux/io.h>
  35
  36 #include "nv_tco.h"
  37
  38 /* Module and version information */
  39 #define TCO_VERSION "0.01"
  40 #define TCO_MODULE_NAME "NV_TCO"
  41 #define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
  42
  43 /* internal variables */
  44 static unsigned int tcobase;
  45 static DEFINE_SPINLOCK(tco_lock);       /* Guards the hardware */
  46 static unsigned long timer_alive;
  47 static char tco_expect_close;
  48 static struct pci_dev *tco_pci;
  49
  50 /* the watchdog platform device */
  51 static struct platform_device *nv_tco_platform_device;
  52
  53 /* module parameters */
  54 #define WATCHDOG_HEARTBEAT 30   /* 30 sec default heartbeat (2<heartbeat<39) */
  55 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  56 module_param(heartbeat, int, 0);
  57 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
  58                             "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  59
  60 static bool nowayout = WATCHDOG_NOWAYOUT;
  61 module_param(nowayout, bool, 0);
  62 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
  63                 " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  64
  65 /*
  66  * Some TCO specific functions
  67  */
  68 static inline unsigned char seconds_to_ticks(int seconds)
  69 {
  70         /* the internal timer is stored as ticks which decrement
  71          * every 0.6 seconds */
  72         return (seconds * 10) / 6;
  73 }
  74
  75 static void tco_timer_start(void)
  76 {
  77         u32 val;
  78         unsigned long flags;
  79
  80         spin_lock_irqsave(&tco_lock, flags);
  81         val = inl(TCO_CNT(tcobase));
  82         val &= ~TCO_CNT_TCOHALT;
  83         outl(val, TCO_CNT(tcobase));
  84         spin_unlock_irqrestore(&tco_lock, flags);
  85 }
  86
  87 static void tco_timer_stop(void)
  88 {
  89         u32 val;
  90         unsigned long flags;
  91
  92         spin_lock_irqsave(&tco_lock, flags);
  93         val = inl(TCO_CNT(tcobase));
  94         val |= TCO_CNT_TCOHALT;
  95         outl(val, TCO_CNT(tcobase));
  96         spin_unlock_irqrestore(&tco_lock, flags);
  97 }
  98
  99 static void tco_timer_keepalive(void)
 100 {
 101         unsigned long flags;
 102
 103         spin_lock_irqsave(&tco_lock, flags);
 104         outb(0x01, TCO_RLD(tcobase));
 105         spin_unlock_irqrestore(&tco_lock, flags);
 106 }
 107
 108 static int tco_timer_set_heartbeat(int t)
 109 {
 110         int ret = 0;
 111         unsigned char tmrval;
 112         unsigned long flags;
 113         u8 val;
 114
 115         /*
 116          * note seconds_to_ticks(t) > t, so if t > 0x3f, so is
 117          * tmrval=seconds_to_ticks(t).  Check that the count in seconds isn't
 118          * out of range on it's own (to avoid overflow in tmrval).
 119          */
 120         if (t < 0 || t > 0x3f)
 121                 return -EINVAL;
 122         tmrval = seconds_to_ticks(t);
 123
 124         /* "Values of 0h-3h are ignored and should not be attempted" */
 125         if (tmrval > 0x3f || tmrval < 0x04)
 126                 return -EINVAL;
 127
 128         /* Write new heartbeat to watchdog */
 129         spin_lock_irqsave(&tco_lock, flags);
 130         val = inb(TCO_TMR(tcobase));
 131         val &= 0xc0;
 132         val |= tmrval;
 133         outb(val, TCO_TMR(tcobase));
 134         val = inb(TCO_TMR(tcobase));
 135
 136         if ((val & 0x3f) != tmrval)
 137                 ret = -EINVAL;
 138         spin_unlock_irqrestore(&tco_lock, flags);
 139
 140         if (ret)
 141                 return ret;
 142
 143         heartbeat = t;
 144         return 0;
 145 }
 146
 147 /*
 148  *      /dev/watchdog handling
 149  */
 150
 151 static int nv_tco_open(struct inode *inode, struct file *file)
 152 {
 153         /* /dev/watchdog can only be opened once */
 154         if (test_and_set_bit(0, &timer_alive))
 155                 return -EBUSY;
 156
 157         /* Reload and activate timer */
 158         tco_timer_keepalive();
 159         tco_timer_start();
 160         return stream_open(inode, file);
 161 }
 162
 163 static int nv_tco_release(struct inode *inode, struct file *file)
 164 {
 165         /* Shut off the timer */
 166         if (tco_expect_close == 42) {
 167                 tco_timer_stop();
 168         } else {
 169                 pr_crit("Unexpected close, not stopping watchdog!\n");
 170                 tco_timer_keepalive();
 171         }
 172         clear_bit(0, &timer_alive);
 173         tco_expect_close = 0;
 174         return 0;
 175 }
 176
 177 static ssize_t nv_tco_write(struct file *file, const char __user *data,
 178                             size_t len, loff_t *ppos)
 179 {
 180         /* See if we got the magic character 'V' and reload the timer */
 181         if (len) {
 182                 if (!nowayout) {
 183                         size_t i;
 184
 185                         /*
 186                          * note: just in case someone wrote the magic character
 187                          * five months ago...
 188                          */
 189                         tco_expect_close = 0;
 190
 191                         /*
 192                          * scan to see whether or not we got the magic
 193                          * character
 194                          */
 195                         for (i = 0; i != len; i++) {
 196                                 char c;
 197                                 if (get_user(c, data + i))
 198                                         return -EFAULT;
 199                                 if (c == 'V')
 200                                         tco_expect_close = 42;
 201                         }
 202                 }
 203
 204                 /* someone wrote to us, we should reload the timer */
 205                 tco_timer_keepalive();
 206         }
 207         return len;
 208 }
 209
 210 static long nv_tco_ioctl(struct file *file, unsigned int cmd,
 211                          unsigned long arg)
 212 {
 213         int new_options, retval = -EINVAL;
 214         int new_heartbeat;
 215         void __user *argp = (void __user *)arg;
 216         int __user *p = argp;
 217         static const struct watchdog_info ident = {
 218                 .options =              WDIOF_SETTIMEOUT |
 219                                         WDIOF_KEEPALIVEPING |
 220                                         WDIOF_MAGICCLOSE,
 221                 .firmware_version =     0,
 222                 .identity =             TCO_MODULE_NAME,
 223         };
 224
 225         switch (cmd) {
 226         case WDIOC_GETSUPPORT:
 227                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 228         case WDIOC_GETSTATUS:
 229         case WDIOC_GETBOOTSTATUS:
 230                 return put_user(0, p);
 231         case WDIOC_SETOPTIONS:
 232                 if (get_user(new_options, p))
 233                         return -EFAULT;
 234                 if (new_options & WDIOS_DISABLECARD) {
 235                         tco_timer_stop();
 236                         retval = 0;
 237                 }
 238                 if (new_options & WDIOS_ENABLECARD) {
 239                         tco_timer_keepalive();
 240                         tco_timer_start();
 241                         retval = 0;
 242                 }
 243                 return retval;
 244         case WDIOC_KEEPALIVE:
 245                 tco_timer_keepalive();
 246                 return 0;
 247         case WDIOC_SETTIMEOUT:
 248                 if (get_user(new_heartbeat, p))
 249                         return -EFAULT;
 250                 if (tco_timer_set_heartbeat(new_heartbeat))
 251                         return -EINVAL;
 252                 tco_timer_keepalive();
 253                 fallthrough;
 254         case WDIOC_GETTIMEOUT:
 255                 return put_user(heartbeat, p);
 256         default:
 257                 return -ENOTTY;
 258         }
 259 }
 260
 261 /*
 262  *      Kernel Interfaces
 263  */
 264
 265 static const struct file_operations nv_tco_fops = {
 266         .owner =                THIS_MODULE,
 267         .llseek =               no_llseek,
 268         .write =                nv_tco_write,
 269         .unlocked_ioctl =       nv_tco_ioctl,
 270         .compat_ioctl =         compat_ptr_ioctl,
 271         .open =                 nv_tco_open,
 272         .release =              nv_tco_release,
 273 };
 274
 275 static struct miscdevice nv_tco_miscdev = {
 276         .minor =        WATCHDOG_MINOR,
 277         .name =         "watchdog",
 278         .fops =         &nv_tco_fops,
 279 };
 280
 281 /*
 282  * Data for PCI driver interface
 283  *
 284  * This data only exists for exporting the supported
 285  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 286  * register a pci_driver, because someone else might one day
 287  * want to register another driver on the same PCI id.
 288  */
 289 static const struct pci_device_id tco_pci_tbl[] = {
 290         { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
 291           PCI_ANY_ID, PCI_ANY_ID, },
 292         { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
 293           PCI_ANY_ID, PCI_ANY_ID, },
 294         { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS,
 295           PCI_ANY_ID, PCI_ANY_ID, },
 296         { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS,
 297           PCI_ANY_ID, PCI_ANY_ID, },
 298         { 0, },                 /* End of list */
 299 };
 300 MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
 301
 302 /*
 303  *      Init & exit routines
 304  */
 305
 306 static unsigned char nv_tco_getdevice(void)
 307 {
 308         struct pci_dev *dev = NULL;
 309         u32 val;
 310
 311         /* Find the PCI device */
 312         for_each_pci_dev(dev) {
 313                 if (pci_match_id(tco_pci_tbl, dev) != NULL) {
 314                         tco_pci = dev;
 315                         break;
 316                 }
 317         }
 318
 319         if (!tco_pci)
 320                 return 0;
 321
 322         /* Find the base io port */
 323         pci_read_config_dword(tco_pci, 0x64, &val);
 324         val &= 0xffff;
 325         if (val == 0x0001 || val == 0x0000) {
 326                 /* Something is wrong here, bar isn't setup */
 327                 pr_err("failed to get tcobase address\n");
 328                 return 0;
 329         }
 330         val &= 0xff00;
 331         tcobase = val + 0x40;
 332
 333         if (!request_region(tcobase, 0x10, "NV TCO")) {
 334                 pr_err("I/O address 0x%04x already in use\n", tcobase);
 335                 return 0;
 336         }
 337
 338         /* Set a reasonable heartbeat before we stop the timer */
 339         tco_timer_set_heartbeat(30);
 340
 341         /*
 342          * Stop the TCO before we change anything so we don't race with
 343          * a zeroed timer.
 344          */
 345         tco_timer_keepalive();
 346         tco_timer_stop();
 347
 348         /* Disable SMI caused by TCO */
 349         if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
 350                 pr_err("I/O address 0x%04x already in use\n",
 351                        MCP51_SMI_EN(tcobase));
 352                 goto out;
 353         }
 354         val = inl(MCP51_SMI_EN(tcobase));
 355         val &= ~MCP51_SMI_EN_TCO;
 356         outl(val, MCP51_SMI_EN(tcobase));
 357         val = inl(MCP51_SMI_EN(tcobase));
 358         release_region(MCP51_SMI_EN(tcobase), 4);
 359         if (val & MCP51_SMI_EN_TCO) {
 360                 pr_err("Could not disable SMI caused by TCO\n");
 361                 goto out;
 362         }
 363
 364         /* Check chipset's NO_REBOOT bit */
 365         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 366         val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 367         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 368         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 369         if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
 370                 pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
 371                 goto out;
 372         }
 373
 374         return 1;
 375 out:
 376         release_region(tcobase, 0x10);
 377         return 0;
 378 }
 379
 380 static int nv_tco_init(struct platform_device *dev)
 381 {
 382         int ret;
 383
 384         /* Check whether or not the hardware watchdog is there */
 385         if (!nv_tco_getdevice())
 386                 return -ENODEV;
 387
 388         /* Check to see if last reboot was due to watchdog timeout */
 389         pr_info("Watchdog reboot %sdetected\n",
 390                 inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");
 391
 392         /* Clear out the old status */
 393         outl(TCO_STS_RESET, TCO_STS(tcobase));
 394
 395         /*
 396          * Check that the heartbeat value is within it's range.
 397          * If not, reset to the default.
 398          */
 399         if (tco_timer_set_heartbeat(heartbeat)) {
 400                 heartbeat = WATCHDOG_HEARTBEAT;
 401                 tco_timer_set_heartbeat(heartbeat);
 402                 pr_info("heartbeat value must be 2<heartbeat<39, using %d\n",
 403                         heartbeat);
 404         }
 405
 406         ret = misc_register(&nv_tco_miscdev);
 407         if (ret != 0) {
 408                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 409                        WATCHDOG_MINOR, ret);
 410                 goto unreg_region;
 411         }
 412
 413         clear_bit(0, &timer_alive);
 414
 415         tco_timer_stop();
 416
 417         pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
 418                 tcobase, heartbeat, nowayout);
 419
 420         return 0;
 421
 422 unreg_region:
 423         release_region(tcobase, 0x10);
 424         return ret;
 425 }
 426
 427 static void nv_tco_cleanup(void)
 428 {
 429         u32 val;
 430
 431         /* Stop the timer before we leave */
 432         if (!nowayout)
 433                 tco_timer_stop();
 434
 435         /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
 436         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 437         val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 438         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 439         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 440         if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
 441                 pr_crit("Couldn't unset REBOOT bit.  Machine may soon reset\n");
 442         }
 443
 444         /* Deregister */
 445         misc_deregister(&nv_tco_miscdev);
 446         release_region(tcobase, 0x10);
 447 }
 448
 449 static int nv_tco_remove(struct platform_device *dev)
 450 {
 451         if (tcobase)
 452                 nv_tco_cleanup();
 453
 454         return 0;
 455 }
 456
 457 static void nv_tco_shutdown(struct platform_device *dev)
 458 {
 459         u32 val;
 460
 461         tco_timer_stop();
 462
 463         /* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
 464          * unset during shutdown. */
 465         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 466         val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 467         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 468 }
 469
 470 static struct platform_driver nv_tco_driver = {
 471         .probe          = nv_tco_init,
 472         .remove         = nv_tco_remove,
 473         .shutdown       = nv_tco_shutdown,
 474         .driver         = {
 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");