drivers/watchdog/sp5100_tco.c

   1 /*
   2  *      sp5100_tco :    TCO timer driver for sp5100 chipsets
   3  *
   4  *      (c) Copyright 2009 Google Inc., All Rights Reserved.
   5  *
   6  *      Based on i8xx_tco.c:
   7  *      (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
   8  *      Reserved.
   9  *                              http://www.kernelconcepts.de
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  *
  16  *      See AMD Publication 43009 "AMD SB700/710/750 Register Reference Guide"
  17  */
  18
  19 /*
  20  *      Includes, defines, variables, module parameters, ...
  21  */
  22
  23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25 #include <linux/module.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/types.h>
  28 #include <linux/miscdevice.h>
  29 #include <linux/watchdog.h>
  30 #include <linux/init.h>
  31 #include <linux/fs.h>
  32 #include <linux/pci.h>
  33 #include <linux/ioport.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/uaccess.h>
  36 #include <linux/io.h>
  37
  38 #include "sp5100_tco.h"
  39
  40 /* Module and version information */
  41 #define TCO_VERSION "0.01"
  42 #define TCO_MODULE_NAME "SP5100 TCO timer"
  43 #define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
  44
  45 /* internal variables */
  46 static u32 tcobase_phys;
  47 static void __iomem *tcobase;
  48 static unsigned int pm_iobase;
  49 static DEFINE_SPINLOCK(tco_lock);       /* Guards the hardware */
  50 static unsigned long timer_alive;
  51 static char tco_expect_close;
  52 static struct pci_dev *sp5100_tco_pci;
  53
  54 /* the watchdog platform device */
  55 static struct platform_device *sp5100_tco_platform_device;
  56
  57 /* module parameters */
  58
  59 #define WATCHDOG_HEARTBEAT 60   /* 60 sec default heartbeat. */
  60 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  61 module_param(heartbeat, int, 0);
  62 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
  63                  __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  64
  65 static bool nowayout = WATCHDOG_NOWAYOUT;
  66 module_param(nowayout, bool, 0);
  67 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
  68                 " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  69
  70 /*
  71  * Some TCO specific functions
  72  */
  73 static void tco_timer_start(void)
  74 {
  75         u32 val;
  76         unsigned long flags;
  77
  78         spin_lock_irqsave(&tco_lock, flags);
  79         val = readl(SP5100_WDT_CONTROL(tcobase));
  80         val |= SP5100_WDT_START_STOP_BIT;
  81         writel(val, SP5100_WDT_CONTROL(tcobase));
  82         spin_unlock_irqrestore(&tco_lock, flags);
  83 }
  84
  85 static void tco_timer_stop(void)
  86 {
  87         u32 val;
  88         unsigned long flags;
  89
  90         spin_lock_irqsave(&tco_lock, flags);
  91         val = readl(SP5100_WDT_CONTROL(tcobase));
  92         val &= ~SP5100_WDT_START_STOP_BIT;
  93         writel(val, SP5100_WDT_CONTROL(tcobase));
  94         spin_unlock_irqrestore(&tco_lock, flags);
  95 }
  96
  97 static void tco_timer_keepalive(void)
  98 {
  99         u32 val;
 100         unsigned long flags;
 101
 102         spin_lock_irqsave(&tco_lock, flags);
 103         val = readl(SP5100_WDT_CONTROL(tcobase));
 104         val |= SP5100_WDT_TRIGGER_BIT;
 105         writel(val, SP5100_WDT_CONTROL(tcobase));
 106         spin_unlock_irqrestore(&tco_lock, flags);
 107 }
 108
 109 static int tco_timer_set_heartbeat(int t)
 110 {
 111         unsigned long flags;
 112
 113         if (t < 0 || t > 0xffff)
 114                 return -EINVAL;
 115
 116         /* Write new heartbeat to watchdog */
 117         spin_lock_irqsave(&tco_lock, flags);
 118         writel(t, SP5100_WDT_COUNT(tcobase));
 119         spin_unlock_irqrestore(&tco_lock, flags);
 120
 121         heartbeat = t;
 122         return 0;
 123 }
 124
 125 /*
 126  *      /dev/watchdog handling
 127  */
 128
 129 static int sp5100_tco_open(struct inode *inode, struct file *file)
 130 {
 131         /* /dev/watchdog can only be opened once */
 132         if (test_and_set_bit(0, &timer_alive))
 133                 return -EBUSY;
 134
 135         /* Reload and activate timer */
 136         tco_timer_start();
 137         tco_timer_keepalive();
 138         return nonseekable_open(inode, file);
 139 }
 140
 141 static int sp5100_tco_release(struct inode *inode, struct file *file)
 142 {
 143         /* Shut off the timer. */
 144         if (tco_expect_close == 42) {
 145                 tco_timer_stop();
 146         } else {
 147                 pr_crit("Unexpected close, not stopping watchdog!\n");
 148                 tco_timer_keepalive();
 149         }
 150         clear_bit(0, &timer_alive);
 151         tco_expect_close = 0;
 152         return 0;
 153 }
 154
 155 static ssize_t sp5100_tco_write(struct file *file, const char __user *data,
 156                                 size_t len, loff_t *ppos)
 157 {
 158         /* See if we got the magic character 'V' and reload the timer */
 159         if (len) {
 160                 if (!nowayout) {
 161                         size_t i;
 162
 163                         /* note: just in case someone wrote the magic character
 164                          * five months ago... */
 165                         tco_expect_close = 0;
 166
 167                         /* scan to see whether or not we got the magic character
 168                          */
 169                         for (i = 0; i != len; i++) {
 170                                 char c;
 171                                 if (get_user(c, data + i))
 172                                         return -EFAULT;
 173                                 if (c == 'V')
 174                                         tco_expect_close = 42;
 175                         }
 176                 }
 177
 178                 /* someone wrote to us, we should reload the timer */
 179                 tco_timer_keepalive();
 180         }
 181         return len;
 182 }
 183
 184 static long sp5100_tco_ioctl(struct file *file, unsigned int cmd,
 185                              unsigned long arg)
 186 {
 187         int new_options, retval = -EINVAL;
 188         int new_heartbeat;
 189         void __user *argp = (void __user *)arg;
 190         int __user *p = argp;
 191         static const struct watchdog_info ident = {
 192                 .options =              WDIOF_SETTIMEOUT |
 193                                         WDIOF_KEEPALIVEPING |
 194                                         WDIOF_MAGICCLOSE,
 195                 .firmware_version =     0,
 196                 .identity =             TCO_MODULE_NAME,
 197         };
 198
 199         switch (cmd) {
 200         case WDIOC_GETSUPPORT:
 201                 return copy_to_user(argp, &ident,
 202                         sizeof(ident)) ? -EFAULT : 0;
 203         case WDIOC_GETSTATUS:
 204         case WDIOC_GETBOOTSTATUS:
 205                 return put_user(0, p);
 206         case WDIOC_SETOPTIONS:
 207                 if (get_user(new_options, p))
 208                         return -EFAULT;
 209                 if (new_options & WDIOS_DISABLECARD) {
 210                         tco_timer_stop();
 211                         retval = 0;
 212                 }
 213                 if (new_options & WDIOS_ENABLECARD) {
 214                         tco_timer_start();
 215                         tco_timer_keepalive();
 216                         retval = 0;
 217                 }
 218                 return retval;
 219         case WDIOC_KEEPALIVE:
 220                 tco_timer_keepalive();
 221                 return 0;
 222         case WDIOC_SETTIMEOUT:
 223                 if (get_user(new_heartbeat, p))
 224                         return -EFAULT;
 225                 if (tco_timer_set_heartbeat(new_heartbeat))
 226                         return -EINVAL;
 227                 tco_timer_keepalive();
 228                 /* Fall through */
 229         case WDIOC_GETTIMEOUT:
 230                 return put_user(heartbeat, p);
 231         default:
 232                 return -ENOTTY;
 233         }
 234 }
 235
 236 /*
 237  * Kernel Interfaces
 238  */
 239
 240 static const struct file_operations sp5100_tco_fops = {
 241         .owner =                THIS_MODULE,
 242         .llseek =               no_llseek,
 243         .write =                sp5100_tco_write,
 244         .unlocked_ioctl =       sp5100_tco_ioctl,
 245         .open =                 sp5100_tco_open,
 246         .release =              sp5100_tco_release,
 247 };
 248
 249 static struct miscdevice sp5100_tco_miscdev = {
 250         .minor =        WATCHDOG_MINOR,
 251         .name =         "watchdog",
 252         .fops =         &sp5100_tco_fops,
 253 };
 254
 255 /*
 256  * Data for PCI driver interface
 257  *
 258  * This data only exists for exporting the supported
 259  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 260  * register a pci_driver, because someone else might
 261  * want to register another driver on the same PCI id.
 262  */
 263 static DEFINE_PCI_DEVICE_TABLE(sp5100_tco_pci_tbl) = {
 264         { PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS, PCI_ANY_ID,
 265           PCI_ANY_ID, },
 266         { 0, },                 /* End of list */
 267 };
 268 MODULE_DEVICE_TABLE(pci, sp5100_tco_pci_tbl);
 269
 270 /*
 271  * Init & exit routines
 272  */
 273
 274 static unsigned char __devinit sp5100_tco_setupdevice(void)
 275 {
 276         struct pci_dev *dev = NULL;
 277         u32 val;
 278
 279         /* Match the PCI device */
 280         for_each_pci_dev(dev) {
 281                 if (pci_match_id(sp5100_tco_pci_tbl, dev) != NULL) {
 282                         sp5100_tco_pci = dev;
 283                         break;
 284                 }
 285         }
 286
 287         if (!sp5100_tco_pci)
 288                 return 0;
 289
 290         /* Request the IO ports used by this driver */
 291         pm_iobase = SP5100_IO_PM_INDEX_REG;
 292         if (!request_region(pm_iobase, SP5100_PM_IOPORTS_SIZE, "SP5100 TCO")) {
 293                 pr_err("I/O address 0x%04x already in use\n", pm_iobase);
 294                 goto exit;
 295         }
 296
 297         /* Find the watchdog base address. */
 298         outb(SP5100_PM_WATCHDOG_BASE3, SP5100_IO_PM_INDEX_REG);
 299         val = inb(SP5100_IO_PM_DATA_REG);
 300         outb(SP5100_PM_WATCHDOG_BASE2, SP5100_IO_PM_INDEX_REG);
 301         val = val << 8 | inb(SP5100_IO_PM_DATA_REG);
 302         outb(SP5100_PM_WATCHDOG_BASE1, SP5100_IO_PM_INDEX_REG);
 303         val = val << 8 | inb(SP5100_IO_PM_DATA_REG);
 304         outb(SP5100_PM_WATCHDOG_BASE0, SP5100_IO_PM_INDEX_REG);
 305         /* Low three bits of BASE0 are reserved. */
 306         val = val << 8 | (inb(SP5100_IO_PM_DATA_REG) & 0xf8);
 307
 308         if (!request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE,
 309                                                                 "SP5100 TCO")) {
 310                 pr_err("mmio address 0x%04x already in use\n", val);
 311                 goto unreg_region;
 312         }
 313         tcobase_phys = val;
 314
 315         tcobase = ioremap(val, SP5100_WDT_MEM_MAP_SIZE);
 316         if (!tcobase) {
 317                 pr_err("failed to get tcobase address\n");
 318                 goto unreg_mem_region;
 319         }
 320
 321         /* Enable watchdog decode bit */
 322         pci_read_config_dword(sp5100_tco_pci,
 323                               SP5100_PCI_WATCHDOG_MISC_REG,
 324                               &val);
 325
 326         val |= SP5100_PCI_WATCHDOG_DECODE_EN;
 327
 328         pci_write_config_dword(sp5100_tco_pci,
 329                                SP5100_PCI_WATCHDOG_MISC_REG,
 330                                val);
 331
 332         /* Enable Watchdog timer and set the resolution to 1 sec. */
 333         outb(SP5100_PM_WATCHDOG_CONTROL, SP5100_IO_PM_INDEX_REG);
 334         val = inb(SP5100_IO_PM_DATA_REG);
 335         val |= SP5100_PM_WATCHDOG_SECOND_RES;
 336         val &= ~SP5100_PM_WATCHDOG_DISABLE;
 337         outb(val, SP5100_IO_PM_DATA_REG);
 338
 339         /* Check that the watchdog action is set to reset the system. */
 340         val = readl(SP5100_WDT_CONTROL(tcobase));
 341         val &= ~SP5100_PM_WATCHDOG_ACTION_RESET;
 342         writel(val, SP5100_WDT_CONTROL(tcobase));
 343
 344         /* Set a reasonable heartbeat before we stop the timer */
 345         tco_timer_set_heartbeat(heartbeat);
 346
 347         /*
 348          * Stop the TCO before we change anything so we don't race with
 349          * a zeroed timer.
 350          */
 351         tco_timer_stop();
 352
 353         /* Done */
 354         return 1;
 355
 356 unreg_mem_region:
 357         release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
 358 unreg_region:
 359         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 360 exit:
 361         return 0;
 362 }
 363
 364 static int __devinit sp5100_tco_init(struct platform_device *dev)
 365 {
 366         int ret;
 367         u32 val;
 368
 369         /* Check whether or not the hardware watchdog is there. If found, then
 370          * set it up.
 371          */
 372         if (!sp5100_tco_setupdevice())
 373                 return -ENODEV;
 374
 375         /* Check to see if last reboot was due to watchdog timeout */
 376         pr_info("Watchdog reboot %sdetected\n",
 377                 readl(SP5100_WDT_CONTROL(tcobase)) & SP5100_PM_WATCHDOG_FIRED ?
 378                 "" : "not ");
 379
 380         /* Clear out the old status */
 381         val = readl(SP5100_WDT_CONTROL(tcobase));
 382         val &= ~SP5100_PM_WATCHDOG_FIRED;
 383         writel(val, SP5100_WDT_CONTROL(tcobase));
 384
 385         /*
 386          * Check that the heartbeat value is within it's range.
 387          * If not, reset to the default.
 388          */
 389         if (tco_timer_set_heartbeat(heartbeat)) {
 390                 heartbeat = WATCHDOG_HEARTBEAT;
 391                 tco_timer_set_heartbeat(heartbeat);
 392         }
 393
 394         ret = misc_register(&sp5100_tco_miscdev);
 395         if (ret != 0) {
 396                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 397                        WATCHDOG_MINOR, ret);
 398                 goto exit;
 399         }
 400
 401         clear_bit(0, &timer_alive);
 402
 403         pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
 404                 tcobase, heartbeat, nowayout);
 405
 406         return 0;
 407
 408 exit:
 409         iounmap(tcobase);
 410         release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
 411         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 412         return ret;
 413 }
 414
 415 static void __devexit sp5100_tco_cleanup(void)
 416 {
 417         /* Stop the timer before we leave */
 418         if (!nowayout)
 419                 tco_timer_stop();
 420
 421         /* Deregister */
 422         misc_deregister(&sp5100_tco_miscdev);
 423         iounmap(tcobase);
 424         release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
 425         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 426 }
 427
 428 static int __devexit sp5100_tco_remove(struct platform_device *dev)
 429 {
 430         if (tcobase)
 431                 sp5100_tco_cleanup();
 432         return 0;
 433 }
 434
 435 static void sp5100_tco_shutdown(struct platform_device *dev)
 436 {
 437         tco_timer_stop();
 438 }
 439
 440 static struct platform_driver sp5100_tco_driver = {
 441         .probe          = sp5100_tco_init,
 442         .remove         = __devexit_p(sp5100_tco_remove),
 443         .shutdown       = sp5100_tco_shutdown,
 444         .driver         = {
 445                 .owner  = THIS_MODULE,
 446                 .name   = TCO_MODULE_NAME,
 447         },
 448 };
 449
 450 static int __init sp5100_tco_init_module(void)
 451 {
 452         int err;
 453
 454         pr_info("SP5100 TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
 455
 456         err = platform_driver_register(&sp5100_tco_driver);
 457         if (err)
 458                 return err;
 459
 460         sp5100_tco_platform_device = platform_device_register_simple(
 461                                         TCO_MODULE_NAME, -1, NULL, 0);
 462         if (IS_ERR(sp5100_tco_platform_device)) {
 463                 err = PTR_ERR(sp5100_tco_platform_device);
 464                 goto unreg_platform_driver;
 465         }
 466
 467         return 0;
 468
 469 unreg_platform_driver:
 470         platform_driver_unregister(&sp5100_tco_driver);
 471         return err;
 472 }
 473
 474 static void __exit sp5100_tco_cleanup_module(void)
 475 {
 476         platform_device_unregister(sp5100_tco_platform_device);
 477         platform_driver_unregister(&sp5100_tco_driver);
 478         pr_info("SP5100 TCO Watchdog Module Unloaded\n");
 479 }
 480
 481 module_init(sp5100_tco_init_module);
 482 module_exit(sp5100_tco_cleanup_module);
 483
 484 MODULE_AUTHOR("Priyanka Gupta");
 485 MODULE_DESCRIPTION("TCO timer driver for SP5100 chipset");
 486 MODULE_LICENSE("GPL");
 487 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);