drivers/watchdog/pc87413_wdt.c

   1 /*
   2  *      NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
   3  *
   4  *      This code is based on wdt.c with original copyright.
   5  *
   6  *      (C) Copyright 2006 Sven Anders, <anders@anduras.de>
   7  *                     and Marcus Junker, <junker@anduras.de>
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  *
  14  *      Neither Sven Anders, Marcus Junker nor ANDURAS AG
  15  *      admit liability nor provide warranty for any of this software.
  16  *      This material is provided "AS-IS" and at no charge.
  17  *
  18  *      Release 1.1
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/watchdog.h>
  25 #include <linux/ioport.h>
  26 #include <linux/delay.h>
  27 #include <linux/notifier.h>
  28 #include <linux/fs.h>
  29 #include <linux/reboot.h>
  30 #include <linux/init.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/moduleparam.h>
  33 #include <linux/io.h>
  34 #include <linux/uaccess.h>
  35
  36 #include <asm/system.h>
  37
  38 /* #define DEBUG 1 */
  39
  40 #define DEFAULT_TIMEOUT     1           /* 1 minute */
  41 #define MAX_TIMEOUT         255
  42
  43 #define VERSION             "1.1"
  44 #define MODNAME             "pc87413 WDT"
  45 #define PFX                 MODNAME ": "
  46 #define DPFX                MODNAME " - DEBUG: "
  47
  48 #define WDT_INDEX_IO_PORT   (io+0)      /* I/O port base (index register) */
  49 #define WDT_DATA_IO_PORT    (WDT_INDEX_IO_PORT+1)
  50 #define SWC_LDN             0x04
  51 #define SIOCFG2             0x22        /* Serial IO register */
  52 #define WDCTL               0x10        /* Watchdog-Timer-Controll-Register */
  53 #define WDTO                0x11        /* Watchdog timeout register */
  54 #define WDCFG               0x12        /* Watchdog config register */
  55
  56 static int io = 0x2E;                   /* Address used on Portwell Boards */
  57
  58 static int timeout = DEFAULT_TIMEOUT;   /* timeout value */
  59 static unsigned long timer_enabled;     /* is the timer enabled? */
  60
  61 static char expect_close;               /* is the close expected? */
  62
  63 static DEFINE_SPINLOCK(io_lock);        /* to guard us from io races */
  64
  65 static int nowayout = WATCHDOG_NOWAYOUT;
  66
  67 /* -- Low level function ----------------------------------------*/
  68
  69 /* Select pins for Watchdog output */
  70
  71 static inline void pc87413_select_wdt_out(void)
  72 {
  73         unsigned int cr_data = 0;
  74
  75         /* Step 1: Select multiple pin,pin55,as WDT output */
  76
  77         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  78
  79         cr_data = inb(WDT_DATA_IO_PORT);
  80
  81         cr_data |= 0x80; /* Set Bit7 to 1*/
  82         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  83
  84         outb_p(cr_data, WDT_DATA_IO_PORT);
  85
  86 #ifdef DEBUG
  87         printk(KERN_INFO DPFX
  88                 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
  89                                                                 cr_data);
  90 #endif
  91 }
  92
  93 /* Enable SWC functions */
  94
  95 static inline void pc87413_enable_swc(void)
  96 {
  97         unsigned int cr_data = 0;
  98
  99         /* Step 2: Enable SWC functions */
 100
 101         outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
 102         outb_p(SWC_LDN, WDT_DATA_IO_PORT);
 103
 104         outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
 105         cr_data = inb(WDT_DATA_IO_PORT);
 106         cr_data |= 0x01;                        /* Set Bit0 to 1 */
 107         outb_p(0x30, WDT_INDEX_IO_PORT);
 108         outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */
 109
 110 #ifdef DEBUG
 111         printk(KERN_INFO DPFX "pc87413 - Enable SWC functions\n");
 112 #endif
 113 }
 114
 115 /* Read SWC I/O base address */
 116
 117 static inline unsigned int pc87413_get_swc_base(void)
 118 {
 119         unsigned int  swc_base_addr = 0;
 120         unsigned char addr_l, addr_h = 0;
 121
 122         /* Step 3: Read SWC I/O Base Address */
 123
 124         outb_p(0x60, WDT_INDEX_IO_PORT);        /* Read Index 0x60 */
 125         addr_h = inb(WDT_DATA_IO_PORT);
 126
 127         outb_p(0x61, WDT_INDEX_IO_PORT);        /* Read Index 0x61 */
 128
 129         addr_l = inb(WDT_DATA_IO_PORT);
 130
 131         swc_base_addr = (addr_h << 8) + addr_l;
 132 #ifdef DEBUG
 133         printk(KERN_INFO DPFX
 134                 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
 135                                                 addr_l, addr_h, swc_base_addr);
 136 #endif
 137         return swc_base_addr;
 138 }
 139
 140 /* Select Bank 3 of SWC */
 141
 142 static inline void pc87413_swc_bank3(unsigned int swc_base_addr)
 143 {
 144         /* Step 4: Select Bank3 of SWC */
 145         outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
 146 #ifdef DEBUG
 147         printk(KERN_INFO DPFX "Select Bank3 of SWC\n");
 148 #endif
 149 }
 150
 151 /* Set watchdog timeout to x minutes */
 152
 153 static inline void pc87413_programm_wdto(unsigned int swc_base_addr,
 154                                          char pc87413_time)
 155 {
 156         /* Step 5: Programm WDTO, Twd. */
 157         outb_p(pc87413_time, swc_base_addr + WDTO);
 158 #ifdef DEBUG
 159         printk(KERN_INFO DPFX "Set WDTO to %d minutes\n", pc87413_time);
 160 #endif
 161 }
 162
 163 /* Enable WDEN */
 164
 165 static inline void pc87413_enable_wden(unsigned int swc_base_addr)
 166 {
 167         /* Step 6: Enable WDEN */
 168         outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
 169 #ifdef DEBUG
 170         printk(KERN_INFO DPFX "Enable WDEN\n");
 171 #endif
 172 }
 173
 174 /* Enable SW_WD_TREN */
 175 static inline void pc87413_enable_sw_wd_tren(unsigned int swc_base_addr)
 176 {
 177         /* Enable SW_WD_TREN */
 178         outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
 179 #ifdef DEBUG
 180         printk(KERN_INFO DPFX "Enable SW_WD_TREN\n");
 181 #endif
 182 }
 183
 184 /* Disable SW_WD_TREN */
 185
 186 static inline void pc87413_disable_sw_wd_tren(unsigned int swc_base_addr)
 187 {
 188         /* Disable SW_WD_TREN */
 189         outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
 190 #ifdef DEBUG
 191         printk(KERN_INFO DPFX "pc87413 - Disable SW_WD_TREN\n");
 192 #endif
 193 }
 194
 195 /* Enable SW_WD_TRG */
 196
 197 static inline void pc87413_enable_sw_wd_trg(unsigned int swc_base_addr)
 198 {
 199         /* Enable SW_WD_TRG */
 200         outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
 201 #ifdef DEBUG
 202         printk(KERN_INFO DPFX "pc87413 - Enable SW_WD_TRG\n");
 203 #endif
 204 }
 205
 206 /* Disable SW_WD_TRG */
 207
 208 static inline void pc87413_disable_sw_wd_trg(unsigned int swc_base_addr)
 209 {
 210         /* Disable SW_WD_TRG */
 211         outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
 212 #ifdef DEBUG
 213         printk(KERN_INFO DPFX "Disable SW_WD_TRG\n");
 214 #endif
 215 }
 216
 217 /* -- Higher level functions ------------------------------------*/
 218
 219 /* Enable the watchdog */
 220
 221 static void pc87413_enable(void)
 222 {
 223         unsigned int swc_base_addr;
 224
 225         spin_lock(&io_lock);
 226
 227         pc87413_select_wdt_out();
 228         pc87413_enable_swc();
 229         swc_base_addr = pc87413_get_swc_base();
 230         pc87413_swc_bank3(swc_base_addr);
 231         pc87413_programm_wdto(swc_base_addr, timeout);
 232         pc87413_enable_wden(swc_base_addr);
 233         pc87413_enable_sw_wd_tren(swc_base_addr);
 234         pc87413_enable_sw_wd_trg(swc_base_addr);
 235
 236         spin_unlock(&io_lock);
 237 }
 238
 239 /* Disable the watchdog */
 240
 241 static void pc87413_disable(void)
 242 {
 243         unsigned int swc_base_addr;
 244
 245         spin_lock(&io_lock);
 246
 247         pc87413_select_wdt_out();
 248         pc87413_enable_swc();
 249         swc_base_addr = pc87413_get_swc_base();
 250         pc87413_swc_bank3(swc_base_addr);
 251         pc87413_disable_sw_wd_tren(swc_base_addr);
 252         pc87413_disable_sw_wd_trg(swc_base_addr);
 253         pc87413_programm_wdto(swc_base_addr, 0);
 254
 255         spin_unlock(&io_lock);
 256 }
 257
 258 /* Refresh the watchdog */
 259
 260 static void pc87413_refresh(void)
 261 {
 262         unsigned int swc_base_addr;
 263
 264         spin_lock(&io_lock);
 265
 266         pc87413_select_wdt_out();
 267         pc87413_enable_swc();
 268         swc_base_addr = pc87413_get_swc_base();
 269         pc87413_swc_bank3(swc_base_addr);
 270         pc87413_disable_sw_wd_tren(swc_base_addr);
 271         pc87413_disable_sw_wd_trg(swc_base_addr);
 272         pc87413_programm_wdto(swc_base_addr, timeout);
 273         pc87413_enable_wden(swc_base_addr);
 274         pc87413_enable_sw_wd_tren(swc_base_addr);
 275         pc87413_enable_sw_wd_trg(swc_base_addr);
 276
 277         spin_unlock(&io_lock);
 278 }
 279
 280 /* -- File operations -------------------------------------------*/
 281
 282 /**
 283  *      pc87413_open:
 284  *      @inode: inode of device
 285  *      @file: file handle to device
 286  *
 287  */
 288
 289 static int pc87413_open(struct inode *inode, struct file *file)
 290 {
 291         /* /dev/watchdog can only be opened once */
 292
 293         if (test_and_set_bit(0, &timer_enabled))
 294                 return -EBUSY;
 295
 296         if (nowayout)
 297                 __module_get(THIS_MODULE);
 298
 299         /* Reload and activate timer */
 300         pc87413_refresh();
 301
 302         printk(KERN_INFO MODNAME
 303                 "Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
 304
 305         return nonseekable_open(inode, file);
 306 }
 307
 308 /**
 309  *      pc87413_release:
 310  *      @inode: inode to board
 311  *      @file: file handle to board
 312  *
 313  *      The watchdog has a configurable API. There is a religious dispute
 314  *      between people who want their watchdog to be able to shut down and
 315  *      those who want to be sure if the watchdog manager dies the machine
 316  *      reboots. In the former case we disable the counters, in the latter
 317  *      case you have to open it again very soon.
 318  */
 319
 320 static int pc87413_release(struct inode *inode, struct file *file)
 321 {
 322         /* Shut off the timer. */
 323
 324         if (expect_close == 42) {
 325                 pc87413_disable();
 326                 printk(KERN_INFO MODNAME
 327                                 "Watchdog disabled, sleeping again...\n");
 328         } else {
 329                 printk(KERN_CRIT MODNAME
 330                                 "Unexpected close, not stopping watchdog!\n");
 331                 pc87413_refresh();
 332         }
 333         clear_bit(0, &timer_enabled);
 334         expect_close = 0;
 335         return 0;
 336 }
 337
 338 /**
 339  *      pc87413_status:
 340  *
 341  *      return, if the watchdog is enabled (timeout is set...)
 342  */
 343
 344
 345 static int pc87413_status(void)
 346 {
 347           return 0; /* currently not supported */
 348 }
 349
 350 /**
 351  *      pc87413_write:
 352  *      @file: file handle to the watchdog
 353  *      @data: data buffer to write
 354  *      @len: length in bytes
 355  *      @ppos: pointer to the position to write. No seeks allowed
 356  *
 357  *      A write to a watchdog device is defined as a keepalive signal. Any
 358  *      write of data will do, as we we don't define content meaning.
 359  */
 360
 361 static ssize_t pc87413_write(struct file *file, const char __user *data,
 362                              size_t len, loff_t *ppos)
 363 {
 364         /* See if we got the magic character 'V' and reload the timer */
 365         if (len) {
 366                 if (!nowayout) {
 367                         size_t i;
 368
 369                         /* reset expect flag */
 370                         expect_close = 0;
 371
 372                         /* scan to see whether or not we got the
 373                            magic character */
 374                         for (i = 0; i != len; i++) {
 375                                 char c;
 376                                 if (get_user(c, data + i))
 377                                         return -EFAULT;
 378                                 if (c == 'V')
 379                                         expect_close = 42;
 380                         }
 381                 }
 382
 383                 /* someone wrote to us, we should reload the timer */
 384                 pc87413_refresh();
 385         }
 386         return len;
 387 }
 388
 389 /**
 390  *      pc87413_ioctl:
 391  *      @file: file handle to the device
 392  *      @cmd: watchdog command
 393  *      @arg: argument pointer
 394  *
 395  *      The watchdog API defines a common set of functions for all watchdogs
 396  *      according to their available features. We only actually usefully support
 397  *      querying capabilities and current status.
 398  */
 399
 400 static long pc87413_ioctl(struct file *file, unsigned int cmd,
 401                                                 unsigned long arg)
 402 {
 403         int new_timeout;
 404
 405         union {
 406                 struct watchdog_info __user *ident;
 407                 int __user *i;
 408         } uarg;
 409
 410         static struct watchdog_info ident = {
 411                 .options          = WDIOF_KEEPALIVEPING |
 412                                     WDIOF_SETTIMEOUT |
 413                                     WDIOF_MAGICCLOSE,
 414                 .firmware_version = 1,
 415                 .identity         = "PC87413(HF/F) watchdog",
 416         };
 417
 418         uarg.i = (int __user *)arg;
 419
 420         switch (cmd) {
 421         case WDIOC_GETSUPPORT:
 422                 return copy_to_user(uarg.ident, &ident,
 423                                         sizeof(ident)) ? -EFAULT : 0;
 424         case WDIOC_GETSTATUS:
 425                 return put_user(pc87413_status(), uarg.i);
 426         case WDIOC_GETBOOTSTATUS:
 427                 return put_user(0, uarg.i);
 428         case WDIOC_SETOPTIONS:
 429         {
 430                 int options, retval = -EINVAL;
 431                 if (get_user(options, uarg.i))
 432                         return -EFAULT;
 433                 if (options & WDIOS_DISABLECARD) {
 434                         pc87413_disable();
 435                         retval = 0;
 436                 }
 437                 if (options & WDIOS_ENABLECARD) {
 438                         pc87413_enable();
 439                         retval = 0;
 440                 }
 441                 return retval;
 442         }
 443         case WDIOC_KEEPALIVE:
 444                 pc87413_refresh();
 445 #ifdef DEBUG
 446                 printk(KERN_INFO DPFX "keepalive\n");
 447 #endif
 448                 return 0;
 449         case WDIOC_SETTIMEOUT:
 450                 if (get_user(new_timeout, uarg.i))
 451                         return -EFAULT;
 452                 /* the API states this is given in secs */
 453                 new_timeout /= 60;
 454                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 455                         return -EINVAL;
 456                 timeout = new_timeout;
 457                 pc87413_refresh();
 458                 /* fall through and return the new timeout... */
 459         case WDIOC_GETTIMEOUT:
 460                 new_timeout = timeout * 60;
 461                 return put_user(new_timeout, uarg.i);
 462         default:
 463                 return -ENOTTY;
 464         }
 465 }
 466
 467 /* -- Notifier funtions -----------------------------------------*/
 468
 469 /**
 470  *      notify_sys:
 471  *      @this: our notifier block
 472  *      @code: the event being reported
 473  *      @unused: unused
 474  *
 475  *      Our notifier is called on system shutdowns. We want to turn the card
 476  *      off at reboot otherwise the machine will reboot again during memory
 477  *      test or worse yet during the following fsck. This would suck, in fact
 478  *      trust me - if it happens it does suck.
 479  */
 480
 481 static int pc87413_notify_sys(struct notifier_block *this,
 482                               unsigned long code,
 483                               void *unused)
 484 {
 485         if (code == SYS_DOWN || code == SYS_HALT)
 486                 /* Turn the card off */
 487                 pc87413_disable();
 488         return NOTIFY_DONE;
 489 }
 490
 491 /* -- Module's structures ---------------------------------------*/
 492
 493 static const struct file_operations pc87413_fops = {
 494         .owner          = THIS_MODULE,
 495         .llseek         = no_llseek,
 496         .write          = pc87413_write,
 497         .unlocked_ioctl = pc87413_ioctl,
 498         .open           = pc87413_open,
 499         .release        = pc87413_release,
 500 };
 501
 502 static struct notifier_block pc87413_notifier = {
 503         .notifier_call  = pc87413_notify_sys,
 504 };
 505
 506 static struct miscdevice pc87413_miscdev = {
 507         .minor          = WATCHDOG_MINOR,
 508         .name           = "watchdog",
 509         .fops           = &pc87413_fops,
 510 };
 511
 512 /* -- Module init functions -------------------------------------*/
 513
 514 /**
 515  *      pc87413_init: module's "constructor"
 516  *
 517  *      Set up the WDT watchdog board. All we have to do is grab the
 518  *      resources we require and bitch if anyone beat us to them.
 519  *      The open() function will actually kick the board off.
 520  */
 521
 522 static int __init pc87413_init(void)
 523 {
 524         int ret;
 525
 526         printk(KERN_INFO PFX "Version " VERSION " at io 0x%X\n",
 527                                                         WDT_INDEX_IO_PORT);
 528
 529         /* request_region(io, 2, "pc87413"); */
 530
 531         ret = register_reboot_notifier(&pc87413_notifier);
 532         if (ret != 0) {
 533                 printk(KERN_ERR PFX
 534                         "cannot register reboot notifier (err=%d)\n", ret);
 535         }
 536
 537         ret = misc_register(&pc87413_miscdev);
 538         if (ret != 0) {
 539                 printk(KERN_ERR PFX
 540                         "cannot register miscdev on minor=%d (err=%d)\n",
 541                         WATCHDOG_MINOR, ret);
 542                 unregister_reboot_notifier(&pc87413_notifier);
 543                 return ret;
 544         }
 545         printk(KERN_INFO PFX "initialized. timeout=%d min \n", timeout);
 546         pc87413_enable();
 547         return 0;
 548 }
 549
 550 /**
 551  *      pc87413_exit: module's "destructor"
 552  *
 553  *      Unload the watchdog. You cannot do this with any file handles open.
 554  *      If your watchdog is set to continue ticking on close and you unload
 555  *      it, well it keeps ticking. We won't get the interrupt but the board
 556  *      will not touch PC memory so all is fine. You just have to load a new
 557  *      module in 60 seconds or reboot.
 558  */
 559
 560 static void __exit pc87413_exit(void)
 561 {
 562         /* Stop the timer before we leave */
 563         if (!nowayout) {
 564                 pc87413_disable();
 565                 printk(KERN_INFO MODNAME "Watchdog disabled.\n");
 566         }
 567
 568         misc_deregister(&pc87413_miscdev);
 569         unregister_reboot_notifier(&pc87413_notifier);
 570         /* release_region(io, 2); */
 571
 572         printk(KERN_INFO MODNAME " watchdog component driver removed.\n");
 573 }
 574
 575 module_init(pc87413_init);
 576 module_exit(pc87413_exit);
 577
 578 MODULE_AUTHOR("Sven Anders <anders@anduras.de>, "
 579                 "Marcus Junker <junker@anduras.de>,");
 580 MODULE_DESCRIPTION("PC87413 WDT driver");
 581 MODULE_LICENSE("GPL");
 582
 583 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 584
 585 module_param(io, int, 0);
 586 MODULE_PARM_DESC(io, MODNAME " I/O port (default: " __MODULE_STRING(io) ").");
 587
 588 module_param(timeout, int, 0);
 589 MODULE_PARM_DESC(timeout,
 590                 "Watchdog timeout in minutes (default="
 591                                 __MODULE_STRING(timeout) ").");
 592
 593 module_param(nowayout, int, 0);
 594 MODULE_PARM_DESC(nowayout,
 595                 "Watchdog cannot be stopped once started (default="
 596                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 597