drivers/char/watchdog/i6300esb.c

   1 /*
   2  *      i6300esb:       Watchdog timer driver for Intel 6300ESB chipset
   3  *
   4  *      (c) Copyright 2004 Google Inc.
   5  *      (c) Copyright 2005 David Härdeman <david@2gen.com>
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  *
  12  *      based on i810-tco.c which is in turn based on softdog.c
  13  *
  14  *      The timer is implemented in the following I/O controller hubs:
  15  *      (See the intel documentation on http://developer.intel.com.)
  16  *      6300ESB chip : document number 300641-003
  17  *
  18  *  2004YYZZ Ross Biro
  19  *      Initial version 0.01
  20  *  2004YYZZ Ross Biro
  21  *      Version 0.02
  22  *  20050210 David Härdeman <david@2gen.com>
  23  *      Ported driver to kernel 2.6
  24  */
  25
  26 /*
  27  *      Includes, defines, variables, module parameters, ...
  28  */
  29
  30 #include <linux/module.h>
  31 #include <linux/types.h>
  32 #include <linux/kernel.h>
  33 #include <linux/fs.h>
  34 #include <linux/mm.h>
  35 #include <linux/miscdevice.h>
  36 #include <linux/watchdog.h>
  37 #include <linux/reboot.h>
  38 #include <linux/init.h>
  39 #include <linux/pci.h>
  40 #include <linux/ioport.h>
  41
  42 #include <asm/uaccess.h>
  43 #include <asm/io.h>
  44
  45 /* Module and version information */
  46 #define ESB_VERSION "0.03"
  47 #define ESB_MODULE_NAME "i6300ESB timer"
  48 #define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
  49 #define PFX ESB_MODULE_NAME ": "
  50
  51 /* PCI configuration registers */
  52 #define ESB_CONFIG_REG  0x60            /* Config register                   */
  53 #define ESB_LOCK_REG    0x68            /* WDT lock register                 */
  54
  55 /* Memory mapped registers */
  56 #define ESB_TIMER1_REG  BASEADDR + 0x00 /* Timer1 value after each reset     */
  57 #define ESB_TIMER2_REG  BASEADDR + 0x04 /* Timer2 value after each reset     */
  58 #define ESB_GINTSR_REG  BASEADDR + 0x08 /* General Interrupt Status Register */
  59 #define ESB_RELOAD_REG  BASEADDR + 0x0c /* Reload register                   */
  60
  61 /* Lock register bits */
  62 #define ESB_WDT_FUNC    ( 0x01 << 2 )   /* Watchdog functionality            */
  63 #define ESB_WDT_ENABLE  ( 0x01 << 1 )   /* Enable WDT                        */
  64 #define ESB_WDT_LOCK    ( 0x01 << 0 )   /* Lock (nowayout)                   */
  65
  66 /* Config register bits */
  67 #define ESB_WDT_REBOOT  ( 0x01 << 5 )   /* Enable reboot on timeout          */
  68 #define ESB_WDT_FREQ    ( 0x01 << 2 )   /* Decrement frequency               */
  69 #define ESB_WDT_INTTYPE ( 0x11 << 0 )   /* Interrupt type on timer1 timeout  */
  70
  71 /* Reload register bits */
  72 #define ESB_WDT_RELOAD ( 0x01 << 8 )    /* prevent timeout                   */
  73
  74 /* Magic constants */
  75 #define ESB_UNLOCK1     0x80            /* Step 1 to unlock reset registers  */
  76 #define ESB_UNLOCK2     0x86            /* Step 2 to unlock reset registers  */
  77
  78 /* internal variables */
  79 static void __iomem *BASEADDR;
  80 static spinlock_t esb_lock; /* Guards the hardware */
  81 static unsigned long timer_alive;
  82 static struct pci_dev *esb_pci;
  83 static unsigned short triggered; /* The status of the watchdog upon boot */
  84 static char esb_expect_close;
  85
  86 /* module parameters */
  87 #define WATCHDOG_HEARTBEAT 30   /* 30 sec default heartbeat (1<heartbeat<2*1023) */
  88 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  89 module_param(heartbeat, int, 0);
  90 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (1<heartbeat<2046, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  91
  92 static int nowayout = WATCHDOG_NOWAYOUT;
  93 module_param(nowayout, int, 0);
  94 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
  95
  96 /*
  97  * Some i6300ESB specific functions
  98  */
  99
 100 /*
 101  * Prepare for reloading the timer by unlocking the proper registers.
 102  * This is performed by first writing 0x80 followed by 0x86 to the
 103  * reload register. After this the appropriate registers can be written
 104  * to once before they need to be unlocked again.
 105  */
 106 static inline void esb_unlock_registers(void) {
 107         writeb(ESB_UNLOCK1, ESB_RELOAD_REG);
 108         writeb(ESB_UNLOCK2, ESB_RELOAD_REG);
 109 }
 110
 111 static void esb_timer_start(void)
 112 {
 113         u8 val;
 114
 115         /* Enable or Enable + Lock? */
 116         val = 0x02 | (nowayout ? 0x01 : 0x00);
 117
 118         pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
 119 }
 120
 121 static int esb_timer_stop(void)
 122 {
 123         u8 val;
 124
 125         spin_lock(&esb_lock);
 126         /* First, reset timers as suggested by the docs */
 127         esb_unlock_registers();
 128         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 129         /* Then disable the WDT */
 130         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
 131         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
 132         spin_unlock(&esb_lock);
 133
 134         /* Returns 0 if the timer was disabled, non-zero otherwise */
 135         return (val & 0x01);
 136 }
 137
 138 static void esb_timer_keepalive(void)
 139 {
 140         spin_lock(&esb_lock);
 141         esb_unlock_registers();
 142         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 143         /* FIXME: Do we need to flush anything here? */
 144         spin_unlock(&esb_lock);
 145 }
 146
 147 static int esb_timer_set_heartbeat(int time)
 148 {
 149         u32 val;
 150
 151         if (time < 0x1 || time > (2 * 0x03ff))
 152                 return -EINVAL;
 153
 154         spin_lock(&esb_lock);
 155
 156         /* We shift by 9, so if we are passed a value of 1 sec,
 157          * val will be 1 << 9 = 512, then write that to two
 158          * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
 159          */
 160         val = time << 9;
 161
 162         /* Write timer 1 */
 163         esb_unlock_registers();
 164         writel(val, ESB_TIMER1_REG);
 165
 166         /* Write timer 2 */
 167         esb_unlock_registers();
 168         writel(val, ESB_TIMER2_REG);
 169
 170         /* Reload */
 171         esb_unlock_registers();
 172         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 173
 174         /* FIXME: Do we need to flush everything out? */
 175
 176         /* Done */
 177         heartbeat = time;
 178         spin_unlock(&esb_lock);
 179         return 0;
 180 }
 181
 182 static int esb_timer_read (void)
 183 {
 184         u32 count;
 185
 186         /* This isn't documented, and doesn't take into
 187          * acount which stage is running, but it looks
 188          * like a 20 bit count down, so we might as well report it.
 189          */
 190         pci_read_config_dword(esb_pci, 0x64, &count);
 191         return (int)count;
 192 }
 193
 194 /*
 195  *      /dev/watchdog handling
 196  */
 197
 198 static int esb_open (struct inode *inode, struct file *file)
 199 {
 200         /* /dev/watchdog can only be opened once */
 201         if (test_and_set_bit(0, &timer_alive))
 202                 return -EBUSY;
 203
 204         /* Reload and activate timer */
 205         esb_timer_keepalive ();
 206         esb_timer_start ();
 207
 208         return nonseekable_open(inode, file);
 209 }
 210
 211 static int esb_release (struct inode *inode, struct file *file)
 212 {
 213         /* Shut off the timer. */
 214         if (esb_expect_close == 42) {
 215                 esb_timer_stop ();
 216         } else {
 217                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 218                 esb_timer_keepalive ();
 219         }
 220         clear_bit(0, &timer_alive);
 221         esb_expect_close = 0;
 222         return 0;
 223 }
 224
 225 static ssize_t esb_write (struct file *file, const char __user *data,
 226                           size_t len, loff_t * ppos)
 227 {
 228         /* See if we got the magic character 'V' and reload the timer */
 229         if (len) {
 230                 if (!nowayout) {
 231                         size_t i;
 232
 233                         /* note: just in case someone wrote the magic character
 234                          * five months ago... */
 235                         esb_expect_close = 0;
 236
 237                         /* scan to see whether or not we got the magic character */
 238                         for (i = 0; i != len; i++) {
 239                                 char c;
 240                                 if(get_user(c, data+i))
 241                                         return -EFAULT;
 242                                 if (c == 'V')
 243                                         esb_expect_close = 42;
 244                         }
 245                 }
 246
 247                 /* someone wrote to us, we should reload the timer */
 248                 esb_timer_keepalive ();
 249         }
 250         return len;
 251 }
 252
 253 static int esb_ioctl (struct inode *inode, struct file *file,
 254                       unsigned int cmd, unsigned long arg)
 255 {
 256         int new_options, retval = -EINVAL;
 257         int new_heartbeat;
 258         void __user *argp = (void __user *)arg;
 259         int __user *p = argp;
 260         static struct watchdog_info ident = {
 261                 .options =              WDIOF_SETTIMEOUT |
 262                                         WDIOF_KEEPALIVEPING |
 263                                         WDIOF_MAGICCLOSE,
 264                 .firmware_version =     0,
 265                 .identity =             ESB_MODULE_NAME,
 266         };
 267
 268         switch (cmd) {
 269                 case WDIOC_GETSUPPORT:
 270                         return copy_to_user(argp, &ident,
 271                                             sizeof (ident)) ? -EFAULT : 0;
 272
 273                 case WDIOC_GETSTATUS:
 274                         return put_user (esb_timer_read(), p);
 275
 276                 case WDIOC_GETBOOTSTATUS:
 277                         return put_user (triggered, p);
 278
 279                 case WDIOC_KEEPALIVE:
 280                         esb_timer_keepalive ();
 281                         return 0;
 282
 283                 case WDIOC_SETOPTIONS:
 284                 {
 285                         if (get_user (new_options, p))
 286                                 return -EFAULT;
 287
 288                         if (new_options & WDIOS_DISABLECARD) {
 289                                 esb_timer_stop ();
 290                                 retval = 0;
 291                         }
 292
 293                         if (new_options & WDIOS_ENABLECARD) {
 294                                 esb_timer_keepalive ();
 295                                 esb_timer_start ();
 296                                 retval = 0;
 297                         }
 298
 299                         return retval;
 300                 }
 301
 302                 case WDIOC_SETTIMEOUT:
 303                 {
 304                         if (get_user(new_heartbeat, p))
 305                                 return -EFAULT;
 306
 307                         if (esb_timer_set_heartbeat(new_heartbeat))
 308                             return -EINVAL;
 309
 310                         esb_timer_keepalive ();
 311                         /* Fall */
 312                 }
 313
 314                 case WDIOC_GETTIMEOUT:
 315                         return put_user(heartbeat, p);
 316
 317                 default:
 318                         return -ENOTTY;
 319         }
 320 }
 321
 322 /*
 323  *      Notify system
 324  */
 325
 326 static int esb_notify_sys (struct notifier_block *this, unsigned long code, void *unused)
 327 {
 328         if (code==SYS_DOWN || code==SYS_HALT) {
 329                 /* Turn the WDT off */
 330                 esb_timer_stop ();
 331         }
 332
 333         return NOTIFY_DONE;
 334 }
 335
 336 /*
 337  *      Kernel Interfaces
 338  */
 339
 340 static const struct file_operations esb_fops = {
 341         .owner =        THIS_MODULE,
 342         .llseek =       no_llseek,
 343         .write =        esb_write,
 344         .ioctl =        esb_ioctl,
 345         .open =         esb_open,
 346         .release =      esb_release,
 347 };
 348
 349 static struct miscdevice esb_miscdev = {
 350         .minor =        WATCHDOG_MINOR,
 351         .name =         "watchdog",
 352         .fops =         &esb_fops,
 353 };
 354
 355 static struct notifier_block esb_notifier = {
 356         .notifier_call =        esb_notify_sys,
 357 };
 358
 359 /*
 360  * Data for PCI driver interface
 361  *
 362  * This data only exists for exporting the supported
 363  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 364  * register a pci_driver, because someone else might one day
 365  * want to register another driver on the same PCI id.
 366  */
 367 static struct pci_device_id esb_pci_tbl[] = {
 368         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
 369         { 0, },                 /* End of list */
 370 };
 371 MODULE_DEVICE_TABLE (pci, esb_pci_tbl);
 372
 373 /*
 374  *      Init & exit routines
 375  */
 376
 377 static unsigned char __init esb_getdevice (void)
 378 {
 379         u8 val1;
 380         unsigned short val2;
 381
 382         struct pci_dev *dev = NULL;
 383         /*
 384          *      Find the PCI device
 385          */
 386
 387         for_each_pci_dev(dev) {
 388                 if (pci_match_id(esb_pci_tbl, dev)) {
 389                         esb_pci = dev;
 390                         break;
 391                 }
 392         }
 393
 394         if (esb_pci) {
 395                 if (pci_enable_device(esb_pci)) {
 396                         printk (KERN_ERR PFX "failed to enable device\n");
 397                         goto err_devput;
 398                 }
 399
 400                 if (pci_request_region(esb_pci, 0, ESB_MODULE_NAME)) {
 401                         printk (KERN_ERR PFX "failed to request region\n");
 402                         goto err_disable;
 403                 }
 404
 405                 BASEADDR = ioremap(pci_resource_start(esb_pci, 0),
 406                                    pci_resource_len(esb_pci, 0));
 407                 if (BASEADDR == NULL) {
 408                         /* Something's wrong here, BASEADDR has to be set */
 409                         printk (KERN_ERR PFX "failed to get BASEADDR\n");
 410                         goto err_release;
 411                 }
 412
 413                 /*
 414                  * The watchdog has two timers, it can be setup so that the
 415                  * expiry of timer1 results in an interrupt and the expiry of
 416                  * timer2 results in a reboot. We set it to not generate
 417                  * any interrupts as there is not much we can do with it
 418                  * right now.
 419                  *
 420                  * We also enable reboots and set the timer frequency to
 421                  * the PCI clock divided by 2^15 (approx 1KHz).
 422                  */
 423                 pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
 424
 425                 /* Check that the WDT isn't already locked */
 426                 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
 427                 if (val1 & ESB_WDT_LOCK)
 428                         printk (KERN_WARNING PFX "nowayout already set\n");
 429
 430                 /* Set the timer to watchdog mode and disable it for now */
 431                 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
 432
 433                 /* Check if the watchdog was previously triggered */
 434                 esb_unlock_registers();
 435                 val2 = readw(ESB_RELOAD_REG);
 436                 triggered = (val2 & (0x01 << 9) >> 9);
 437
 438                 /* Reset trigger flag and timers */
 439                 esb_unlock_registers();
 440                 writew((0x11 << 8), ESB_RELOAD_REG);
 441
 442                 /* Done */
 443                 return 1;
 444
 445 err_release:
 446                 pci_release_region(esb_pci, 0);
 447 err_disable:
 448                 pci_disable_device(esb_pci);
 449 err_devput:
 450                 pci_dev_put(esb_pci);
 451         }
 452         return 0;
 453 }
 454
 455 static int __init watchdog_init (void)
 456 {
 457         int ret;
 458
 459         spin_lock_init(&esb_lock);
 460
 461         /* Check whether or not the hardware watchdog is there */
 462         if (!esb_getdevice () || esb_pci == NULL)
 463                 return -ENODEV;
 464
 465         /* Check that the heartbeat value is within it's range ; if not reset to the default */
 466         if (esb_timer_set_heartbeat (heartbeat)) {
 467                 esb_timer_set_heartbeat (WATCHDOG_HEARTBEAT);
 468                 printk(KERN_INFO PFX "heartbeat value must be 1<heartbeat<2046, using %d\n",
 469                        heartbeat);
 470         }
 471
 472         ret = register_reboot_notifier(&esb_notifier);
 473         if (ret != 0) {
 474                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 475                         ret);
 476                 goto err_unmap;
 477         }
 478
 479         ret = misc_register(&esb_miscdev);
 480         if (ret != 0) {
 481                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 482                         WATCHDOG_MINOR, ret);
 483                 goto err_notifier;
 484         }
 485
 486         esb_timer_stop ();
 487
 488         printk (KERN_INFO PFX "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
 489                 BASEADDR, heartbeat, nowayout);
 490
 491         return 0;
 492
 493 err_notifier:
 494         unregister_reboot_notifier(&esb_notifier);
 495 err_unmap:
 496         iounmap(BASEADDR);
 497 /* err_release: */
 498         pci_release_region(esb_pci, 0);
 499 /* err_disable: */
 500         pci_disable_device(esb_pci);
 501 /* err_devput: */
 502         pci_dev_put(esb_pci);
 503         return ret;
 504 }
 505
 506 static void __exit watchdog_cleanup (void)
 507 {
 508         /* Stop the timer before we leave */
 509         if (!nowayout)
 510                 esb_timer_stop ();
 511
 512         /* Deregister */
 513         misc_deregister(&esb_miscdev);
 514         unregister_reboot_notifier(&esb_notifier);
 515         iounmap(BASEADDR);
 516         pci_release_region(esb_pci, 0);
 517         pci_disable_device(esb_pci);
 518         pci_dev_put(esb_pci);
 519 }
 520
 521 module_init(watchdog_init);
 522 module_exit(watchdog_cleanup);
 523
 524 MODULE_AUTHOR("Ross Biro and David Härdeman");
 525 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
 526 MODULE_LICENSE("GPL");
 527 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);