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 300641-004
  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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  31
  32 #include <linux/module.h>
  33 #include <linux/types.h>
  34 #include <linux/kernel.h>
  35 #include <linux/fs.h>
  36 #include <linux/mm.h>
  37 #include <linux/miscdevice.h>
  38 #include <linux/watchdog.h>
  39 #include <linux/init.h>
  40 #include <linux/pci.h>
  41 #include <linux/ioport.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/io.h>
  44
  45 /* Module and version information */
  46 #define ESB_VERSION "0.05"
  47 #define ESB_MODULE_NAME "i6300ESB timer"
  48 #define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
  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 (0x03 << 0)   /* Interrupt type on timer1 timeout  */
  69
  70 /* Reload register bits */
  71 #define ESB_WDT_TIMEOUT (0x01 << 9)    /* Watchdog timed out                */
  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 DEFINE_SPINLOCK(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 /* We can only use 1 card due to the /dev/watchdog restriction */
  87 static int cards_found;
  88
  89 /* module parameters */
  90 /* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
  91 #define WATCHDOG_HEARTBEAT 30
  92 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  93 module_param(heartbeat, int, 0);
  94 MODULE_PARM_DESC(heartbeat,
  95                 "Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
  96                                 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  97
  98 static bool nowayout = WATCHDOG_NOWAYOUT;
  99 module_param(nowayout, bool, 0);
 100 MODULE_PARM_DESC(nowayout,
 101                 "Watchdog cannot be stopped once started (default="
 102                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 103
 104 /*
 105  * Some i6300ESB specific functions
 106  */
 107
 108 /*
 109  * Prepare for reloading the timer by unlocking the proper registers.
 110  * This is performed by first writing 0x80 followed by 0x86 to the
 111  * reload register. After this the appropriate registers can be written
 112  * to once before they need to be unlocked again.
 113  */
 114 static inline void esb_unlock_registers(void)
 115 {
 116         writew(ESB_UNLOCK1, ESB_RELOAD_REG);
 117         writew(ESB_UNLOCK2, ESB_RELOAD_REG);
 118 }
 119
 120 static int esb_timer_start(void)
 121 {
 122         u8 val;
 123
 124         spin_lock(&esb_lock);
 125         esb_unlock_registers();
 126         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 127         /* Enable or Enable + Lock? */
 128         val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
 129         pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
 130         spin_unlock(&esb_lock);
 131         return 0;
 132 }
 133
 134 static int esb_timer_stop(void)
 135 {
 136         u8 val;
 137
 138         spin_lock(&esb_lock);
 139         /* First, reset timers as suggested by the docs */
 140         esb_unlock_registers();
 141         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 142         /* Then disable the WDT */
 143         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
 144         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
 145         spin_unlock(&esb_lock);
 146
 147         /* Returns 0 if the timer was disabled, non-zero otherwise */
 148         return val & ESB_WDT_ENABLE;
 149 }
 150
 151 static void esb_timer_keepalive(void)
 152 {
 153         spin_lock(&esb_lock);
 154         esb_unlock_registers();
 155         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 156         /* FIXME: Do we need to flush anything here? */
 157         spin_unlock(&esb_lock);
 158 }
 159
 160 static int esb_timer_set_heartbeat(int time)
 161 {
 162         u32 val;
 163
 164         if (time < 0x1 || time > (2 * 0x03ff))
 165                 return -EINVAL;
 166
 167         spin_lock(&esb_lock);
 168
 169         /* We shift by 9, so if we are passed a value of 1 sec,
 170          * val will be 1 << 9 = 512, then write that to two
 171          * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
 172          */
 173         val = time << 9;
 174
 175         /* Write timer 1 */
 176         esb_unlock_registers();
 177         writel(val, ESB_TIMER1_REG);
 178
 179         /* Write timer 2 */
 180         esb_unlock_registers();
 181         writel(val, ESB_TIMER2_REG);
 182
 183         /* Reload */
 184         esb_unlock_registers();
 185         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 186
 187         /* FIXME: Do we need to flush everything out? */
 188
 189         /* Done */
 190         heartbeat = time;
 191         spin_unlock(&esb_lock);
 192         return 0;
 193 }
 194
 195 /*
 196  *      /dev/watchdog handling
 197  */
 198
 199 static int esb_open(struct inode *inode, struct file *file)
 200 {
 201         /* /dev/watchdog can only be opened once */
 202         if (test_and_set_bit(0, &timer_alive))
 203                 return -EBUSY;
 204
 205         /* Reload and activate timer */
 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                 pr_crit("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
 238                          * magic character */
 239                         for (i = 0; i != len; i++) {
 240                                 char c;
 241                                 if (get_user(c, data + i))
 242                                         return -EFAULT;
 243                                 if (c == 'V')
 244                                         esb_expect_close = 42;
 245                         }
 246                 }
 247
 248                 /* someone wrote to us, we should reload the timer */
 249                 esb_timer_keepalive();
 250         }
 251         return len;
 252 }
 253
 254 static long esb_ioctl(struct file *file, 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 const 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(0, p);
 275
 276         case WDIOC_GETBOOTSTATUS:
 277                 return put_user(triggered, p);
 278
 279         case WDIOC_SETOPTIONS:
 280         {
 281                 if (get_user(new_options, p))
 282                         return -EFAULT;
 283
 284                 if (new_options & WDIOS_DISABLECARD) {
 285                         esb_timer_stop();
 286                         retval = 0;
 287                 }
 288
 289                 if (new_options & WDIOS_ENABLECARD) {
 290                         esb_timer_start();
 291                         retval = 0;
 292                 }
 293                 return retval;
 294         }
 295         case WDIOC_KEEPALIVE:
 296                 esb_timer_keepalive();
 297                 return 0;
 298
 299         case WDIOC_SETTIMEOUT:
 300         {
 301                 if (get_user(new_heartbeat, p))
 302                         return -EFAULT;
 303                 if (esb_timer_set_heartbeat(new_heartbeat))
 304                         return -EINVAL;
 305                 esb_timer_keepalive();
 306                 /* Fall */
 307         }
 308         case WDIOC_GETTIMEOUT:
 309                 return put_user(heartbeat, p);
 310         default:
 311                 return -ENOTTY;
 312         }
 313 }
 314
 315 /*
 316  *      Kernel Interfaces
 317  */
 318
 319 static const struct file_operations esb_fops = {
 320         .owner = THIS_MODULE,
 321         .llseek = no_llseek,
 322         .write = esb_write,
 323         .unlocked_ioctl = esb_ioctl,
 324         .open = esb_open,
 325         .release = esb_release,
 326 };
 327
 328 static struct miscdevice esb_miscdev = {
 329         .minor = WATCHDOG_MINOR,
 330         .name = "watchdog",
 331         .fops = &esb_fops,
 332 };
 333
 334 /*
 335  * Data for PCI driver interface
 336  */
 337 static DEFINE_PCI_DEVICE_TABLE(esb_pci_tbl) = {
 338         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
 339         { 0, },                 /* End of list */
 340 };
 341 MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
 342
 343 /*
 344  *      Init & exit routines
 345  */
 346
 347 static unsigned char esb_getdevice(struct pci_dev *pdev)
 348 {
 349         if (pci_enable_device(pdev)) {
 350                 pr_err("failed to enable device\n");
 351                 goto err_devput;
 352         }
 353
 354         if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
 355                 pr_err("failed to request region\n");
 356                 goto err_disable;
 357         }
 358
 359         BASEADDR = pci_ioremap_bar(pdev, 0);
 360         if (BASEADDR == NULL) {
 361                 /* Something's wrong here, BASEADDR has to be set */
 362                 pr_err("failed to get BASEADDR\n");
 363                 goto err_release;
 364         }
 365
 366         /* Done */
 367         esb_pci = pdev;
 368         return 1;
 369
 370 err_release:
 371         pci_release_region(pdev, 0);
 372 err_disable:
 373         pci_disable_device(pdev);
 374 err_devput:
 375         return 0;
 376 }
 377
 378 static void esb_initdevice(void)
 379 {
 380         u8 val1;
 381         u16 val2;
 382
 383         /*
 384          * Config register:
 385          * Bit    5 : 0 = Enable WDT_OUTPUT
 386          * Bit    2 : 0 = set the timer frequency to the PCI clock
 387          * divided by 2^15 (approx 1KHz).
 388          * Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
 389          * The watchdog has two timers, it can be setup so that the
 390          * expiry of timer1 results in an interrupt and the expiry of
 391          * timer2 results in a reboot. We set it to not generate
 392          * any interrupts as there is not much we can do with it
 393          * right now.
 394          */
 395         pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
 396
 397         /* Check that the WDT isn't already locked */
 398         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
 399         if (val1 & ESB_WDT_LOCK)
 400                 pr_warn("nowayout already set\n");
 401
 402         /* Set the timer to watchdog mode and disable it for now */
 403         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
 404
 405         /* Check if the watchdog was previously triggered */
 406         esb_unlock_registers();
 407         val2 = readw(ESB_RELOAD_REG);
 408         if (val2 & ESB_WDT_TIMEOUT)
 409                 triggered = WDIOF_CARDRESET;
 410
 411         /* Reset WDT_TIMEOUT flag and timers */
 412         esb_unlock_registers();
 413         writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
 414
 415         /* And set the correct timeout value */
 416         esb_timer_set_heartbeat(heartbeat);
 417 }
 418
 419 static int esb_probe(struct pci_dev *pdev,
 420                 const struct pci_device_id *ent)
 421 {
 422         int ret;
 423
 424         cards_found++;
 425         if (cards_found == 1)
 426                 pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
 427                         ESB_VERSION);
 428
 429         if (cards_found > 1) {
 430                 pr_err("This driver only supports 1 device\n");
 431                 return -ENODEV;
 432         }
 433
 434         /* Check whether or not the hardware watchdog is there */
 435         if (!esb_getdevice(pdev) || esb_pci == NULL)
 436                 return -ENODEV;
 437
 438         /* Check that the heartbeat value is within it's range;
 439            if not reset to the default */
 440         if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
 441                 heartbeat = WATCHDOG_HEARTBEAT;
 442                 pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
 443                         heartbeat);
 444         }
 445
 446         /* Initialize the watchdog and make sure it does not run */
 447         esb_initdevice();
 448
 449         /* Register the watchdog so that userspace has access to it */
 450         ret = misc_register(&esb_miscdev);
 451         if (ret != 0) {
 452                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 453                        WATCHDOG_MINOR, ret);
 454                 goto err_unmap;
 455         }
 456         pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
 457                 BASEADDR, heartbeat, nowayout);
 458         return 0;
 459
 460 err_unmap:
 461         iounmap(BASEADDR);
 462         pci_release_region(esb_pci, 0);
 463         pci_disable_device(esb_pci);
 464         esb_pci = NULL;
 465         return ret;
 466 }
 467
 468 static void esb_remove(struct pci_dev *pdev)
 469 {
 470         /* Stop the timer before we leave */
 471         if (!nowayout)
 472                 esb_timer_stop();
 473
 474         /* Deregister */
 475         misc_deregister(&esb_miscdev);
 476         iounmap(BASEADDR);
 477         pci_release_region(esb_pci, 0);
 478         pci_disable_device(esb_pci);
 479         esb_pci = NULL;
 480 }
 481
 482 static void esb_shutdown(struct pci_dev *pdev)
 483 {
 484         esb_timer_stop();
 485 }
 486
 487 static struct pci_driver esb_driver = {
 488         .name           = ESB_MODULE_NAME,
 489         .id_table       = esb_pci_tbl,
 490         .probe          = esb_probe,
 491         .remove         = esb_remove,
 492         .shutdown       = esb_shutdown,
 493 };
 494
 495 module_pci_driver(esb_driver);
 496
 497 MODULE_AUTHOR("Ross Biro and David Härdeman");
 498 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
 499 MODULE_LICENSE("GPL");
 500 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);