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 #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/platform_device.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 "0.04"
  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_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 static struct platform_device *esb_platform_device;
  86
  87 /* module parameters */
  88 /* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
  89 #define WATCHDOG_HEARTBEAT 30
  90 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  91 module_param(heartbeat, int, 0);
  92 MODULE_PARM_DESC(heartbeat,
  93                 "Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
  94                                 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  95
  96 static int nowayout = WATCHDOG_NOWAYOUT;
  97 module_param(nowayout, int, 0);
  98 MODULE_PARM_DESC(nowayout,
  99                 "Watchdog cannot be stopped once started (default="
 100                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 101
 102 /*
 103  * Some i6300ESB specific functions
 104  */
 105
 106 /*
 107  * Prepare for reloading the timer by unlocking the proper registers.
 108  * This is performed by first writing 0x80 followed by 0x86 to the
 109  * reload register. After this the appropriate registers can be written
 110  * to once before they need to be unlocked again.
 111  */
 112 static inline void esb_unlock_registers(void)
 113 {
 114         writeb(ESB_UNLOCK1, ESB_RELOAD_REG);
 115         writeb(ESB_UNLOCK2, ESB_RELOAD_REG);
 116 }
 117
 118 static int esb_timer_start(void)
 119 {
 120         u8 val;
 121
 122         spin_lock(&esb_lock);
 123         esb_unlock_registers();
 124         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 125         /* Enable or Enable + Lock? */
 126         val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
 127         pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
 128         spin_unlock(&esb_lock);
 129         return 0;
 130 }
 131
 132 static int esb_timer_stop(void)
 133 {
 134         u8 val;
 135
 136         spin_lock(&esb_lock);
 137         /* First, reset timers as suggested by the docs */
 138         esb_unlock_registers();
 139         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 140         /* Then disable the WDT */
 141         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
 142         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
 143         spin_unlock(&esb_lock);
 144
 145         /* Returns 0 if the timer was disabled, non-zero otherwise */
 146         return val & ESB_WDT_ENABLE;
 147 }
 148
 149 static void esb_timer_keepalive(void)
 150 {
 151         spin_lock(&esb_lock);
 152         esb_unlock_registers();
 153         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 154         /* FIXME: Do we need to flush anything here? */
 155         spin_unlock(&esb_lock);
 156 }
 157
 158 static int esb_timer_set_heartbeat(int time)
 159 {
 160         u32 val;
 161
 162         if (time < 0x1 || time > (2 * 0x03ff))
 163                 return -EINVAL;
 164
 165         spin_lock(&esb_lock);
 166
 167         /* We shift by 9, so if we are passed a value of 1 sec,
 168          * val will be 1 << 9 = 512, then write that to two
 169          * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
 170          */
 171         val = time << 9;
 172
 173         /* Write timer 1 */
 174         esb_unlock_registers();
 175         writel(val, ESB_TIMER1_REG);
 176
 177         /* Write timer 2 */
 178         esb_unlock_registers();
 179         writel(val, ESB_TIMER2_REG);
 180
 181         /* Reload */
 182         esb_unlock_registers();
 183         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 184
 185         /* FIXME: Do we need to flush everything out? */
 186
 187         /* Done */
 188         heartbeat = time;
 189         spin_unlock(&esb_lock);
 190         return 0;
 191 }
 192
 193 /*
 194  *      /dev/watchdog handling
 195  */
 196
 197 static int esb_open(struct inode *inode, struct file *file)
 198 {
 199         /* /dev/watchdog can only be opened once */
 200         if (test_and_set_bit(0, &timer_alive))
 201                 return -EBUSY;
 202
 203         /* Reload and activate timer */
 204         esb_timer_start();
 205
 206         return nonseekable_open(inode, file);
 207 }
 208
 209 static int esb_release(struct inode *inode, struct file *file)
 210 {
 211         /* Shut off the timer. */
 212         if (esb_expect_close == 42)
 213                 esb_timer_stop();
 214         else {
 215                 printk(KERN_CRIT PFX
 216                                 "Unexpected close, not stopping watchdog!\n");
 217                 esb_timer_keepalive();
 218         }
 219         clear_bit(0, &timer_alive);
 220         esb_expect_close = 0;
 221         return 0;
 222 }
 223
 224 static ssize_t esb_write(struct file *file, const char __user *data,
 225                           size_t len, loff_t *ppos)
 226 {
 227         /* See if we got the magic character 'V' and reload the timer */
 228         if (len) {
 229                 if (!nowayout) {
 230                         size_t i;
 231
 232                         /* note: just in case someone wrote the magic character
 233                          * five months ago... */
 234                         esb_expect_close = 0;
 235
 236                         /* scan to see whether or not we got the
 237                          * 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 long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 254 {
 255         int new_options, retval = -EINVAL;
 256         int new_heartbeat;
 257         void __user *argp = (void __user *)arg;
 258         int __user *p = argp;
 259         static struct watchdog_info ident = {
 260                 .options =              WDIOF_SETTIMEOUT |
 261                                         WDIOF_KEEPALIVEPING |
 262                                         WDIOF_MAGICCLOSE,
 263                 .firmware_version =     0,
 264                 .identity =             ESB_MODULE_NAME,
 265         };
 266
 267         switch (cmd) {
 268         case WDIOC_GETSUPPORT:
 269                 return copy_to_user(argp, &ident,
 270                                         sizeof(ident)) ? -EFAULT : 0;
 271
 272         case WDIOC_GETSTATUS:
 273                 return put_user(0, p);
 274
 275         case WDIOC_GETBOOTSTATUS:
 276                 return put_user(triggered, p);
 277
 278         case WDIOC_SETOPTIONS:
 279         {
 280                 if (get_user(new_options, p))
 281                         return -EFAULT;
 282
 283                 if (new_options & WDIOS_DISABLECARD) {
 284                         esb_timer_stop();
 285                         retval = 0;
 286                 }
 287
 288                 if (new_options & WDIOS_ENABLECARD) {
 289                         esb_timer_start();
 290                         retval = 0;
 291                 }
 292                 return retval;
 293         }
 294         case WDIOC_KEEPALIVE:
 295                 esb_timer_keepalive();
 296                 return 0;
 297
 298         case WDIOC_SETTIMEOUT:
 299         {
 300                 if (get_user(new_heartbeat, p))
 301                         return -EFAULT;
 302                 if (esb_timer_set_heartbeat(new_heartbeat))
 303                         return -EINVAL;
 304                 esb_timer_keepalive();
 305                 /* Fall */
 306         }
 307         case WDIOC_GETTIMEOUT:
 308                 return put_user(heartbeat, p);
 309         default:
 310                 return -ENOTTY;
 311         }
 312 }
 313
 314 /*
 315  *      Kernel Interfaces
 316  */
 317
 318 static const struct file_operations esb_fops = {
 319         .owner = THIS_MODULE,
 320         .llseek = no_llseek,
 321         .write = esb_write,
 322         .unlocked_ioctl = esb_ioctl,
 323         .open = esb_open,
 324         .release = esb_release,
 325 };
 326
 327 static struct miscdevice esb_miscdev = {
 328         .minor = WATCHDOG_MINOR,
 329         .name = "watchdog",
 330         .fops = &esb_fops,
 331 };
 332
 333 /*
 334  * Data for PCI driver interface
 335  *
 336  * This data only exists for exporting the supported
 337  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 338  * register a pci_driver, because someone else might one day
 339  * want to register another driver on the same PCI id.
 340  */
 341 static struct pci_device_id esb_pci_tbl[] = {
 342         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
 343         { 0, },                 /* End of list */
 344 };
 345 MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
 346
 347 /*
 348  *      Init & exit routines
 349  */
 350
 351 static unsigned char __devinit esb_getdevice(void)
 352 {
 353         /*
 354          *      Find the PCI device
 355          */
 356
 357         esb_pci = pci_get_device(PCI_VENDOR_ID_INTEL,
 358                                         PCI_DEVICE_ID_INTEL_ESB_9, NULL);
 359
 360         if (!esb_pci)
 361                 return 0;
 362
 363         if (pci_enable_device(esb_pci)) {
 364                 printk(KERN_ERR PFX "failed to enable device\n");
 365                 goto err_devput;
 366         }
 367
 368         if (pci_request_region(esb_pci, 0, ESB_MODULE_NAME)) {
 369                 printk(KERN_ERR PFX "failed to request region\n");
 370                 goto err_disable;
 371         }
 372
 373         BASEADDR = pci_ioremap_bar(esb_pci, 0);
 374         if (BASEADDR == NULL) {
 375                 /* Something's wrong here, BASEADDR has to be set */
 376                 printk(KERN_ERR PFX "failed to get BASEADDR\n");
 377                 goto err_release;
 378         }
 379
 380         /* Done */
 381         return 1;
 382
 383 err_release:
 384         pci_release_region(esb_pci, 0);
 385 err_disable:
 386         pci_disable_device(esb_pci);
 387 err_devput:
 388         pci_dev_put(esb_pci);
 389         return 0;
 390 }
 391
 392 static void __devinit esb_initdevice(void)
 393 {
 394         u8 val1;
 395         u16 val2;
 396
 397         /*
 398          * Config register:
 399          * Bit    5 : 0 = Enable WDT_OUTPUT
 400          * Bit    2 : 0 = set the timer frequency to the PCI clock
 401          * divided by 2^15 (approx 1KHz).
 402          * Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
 403          * The watchdog has two timers, it can be setup so that the
 404          * expiry of timer1 results in an interrupt and the expiry of
 405          * timer2 results in a reboot. We set it to not generate
 406          * any interrupts as there is not much we can do with it
 407          * right now.
 408          */
 409         pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
 410
 411         /* Check that the WDT isn't already locked */
 412         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
 413         if (val1 & ESB_WDT_LOCK)
 414                 printk(KERN_WARNING PFX "nowayout already set\n");
 415
 416         /* Set the timer to watchdog mode and disable it for now */
 417         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
 418
 419         /* Check if the watchdog was previously triggered */
 420         esb_unlock_registers();
 421         val2 = readw(ESB_RELOAD_REG);
 422         if (val2 & ESB_WDT_TIMEOUT)
 423                 triggered = WDIOF_CARDRESET;
 424
 425         /* Reset WDT_TIMEOUT flag and timers */
 426         esb_unlock_registers();
 427         writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
 428
 429         /* And set the correct timeout value */
 430         esb_timer_set_heartbeat(heartbeat);
 431 }
 432
 433 static int __devinit esb_probe(struct platform_device *dev)
 434 {
 435         int ret;
 436
 437         /* Check whether or not the hardware watchdog is there */
 438         if (!esb_getdevice() || esb_pci == NULL)
 439                 return -ENODEV;
 440
 441         /* Check that the heartbeat value is within it's range;
 442            if not reset to the default */
 443         if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
 444                 heartbeat = WATCHDOG_HEARTBEAT;
 445                 printk(KERN_INFO PFX
 446                         "heartbeat value must be 1<heartbeat<2046, using %d\n",
 447                                                                 heartbeat);
 448         }
 449
 450         /* Initialize the watchdog and make sure it does not run */
 451         esb_initdevice();
 452
 453         /* Register the watchdog so that userspace has access to it */
 454         ret = misc_register(&esb_miscdev);
 455         if (ret != 0) {
 456                 printk(KERN_ERR PFX
 457                         "cannot register miscdev on minor=%d (err=%d)\n",
 458                                                         WATCHDOG_MINOR, ret);
 459                 goto err_unmap;
 460         }
 461         printk(KERN_INFO PFX
 462                 "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
 463                                                 BASEADDR, heartbeat, nowayout);
 464         return 0;
 465
 466 err_unmap:
 467         iounmap(BASEADDR);
 468         pci_release_region(esb_pci, 0);
 469         pci_disable_device(esb_pci);
 470         pci_dev_put(esb_pci);
 471         return ret;
 472 }
 473
 474 static int __devexit esb_remove(struct platform_device *dev)
 475 {
 476         /* Stop the timer before we leave */
 477         if (!nowayout)
 478                 esb_timer_stop();
 479
 480         /* Deregister */
 481         misc_deregister(&esb_miscdev);
 482         iounmap(BASEADDR);
 483         pci_release_region(esb_pci, 0);
 484         pci_disable_device(esb_pci);
 485         pci_dev_put(esb_pci);
 486         return 0;
 487 }
 488
 489 static void esb_shutdown(struct platform_device *dev)
 490 {
 491         esb_timer_stop();
 492 }
 493
 494 static struct platform_driver esb_platform_driver = {
 495         .probe          = esb_probe,
 496         .remove         = __devexit_p(esb_remove),
 497         .shutdown       = esb_shutdown,
 498         .driver         = {
 499                 .owner  = THIS_MODULE,
 500                 .name   = ESB_MODULE_NAME,
 501         },
 502 };
 503
 504 static int __init watchdog_init(void)
 505 {
 506         int err;
 507
 508         printk(KERN_INFO PFX "Intel 6300ESB WatchDog Timer Driver v%s\n",
 509                 ESB_VERSION);
 510
 511         err = platform_driver_register(&esb_platform_driver);
 512         if (err)
 513                 return err;
 514
 515         esb_platform_device = platform_device_register_simple(ESB_MODULE_NAME,
 516                                                                 -1, NULL, 0);
 517         if (IS_ERR(esb_platform_device)) {
 518                 err = PTR_ERR(esb_platform_device);
 519                 goto unreg_platform_driver;
 520         }
 521
 522         return 0;
 523
 524 unreg_platform_driver:
 525         platform_driver_unregister(&esb_platform_driver);
 526         return err;
 527 }
 528
 529 static void __exit watchdog_cleanup(void)
 530 {
 531         platform_device_unregister(esb_platform_device);
 532         platform_driver_unregister(&esb_platform_driver);
 533         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
 534 }
 535
 536 module_init(watchdog_init);
 537 module_exit(watchdog_cleanup);
 538
 539 MODULE_AUTHOR("Ross Biro and David Härdeman");
 540 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
 541 MODULE_LICENSE("GPL");
 542 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);