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