drivers/watchdog/pc87413_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *      NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
   4  *
   5  *      This code is based on wdt.c with original copyright.
   6  *
   7  *      (C) Copyright 2006 Sven Anders, <anders@anduras.de>
   8  *                     and Marcus Junker, <junker@anduras.de>
   9  *
  10  *      Neither Sven Anders, Marcus Junker nor ANDURAS AG
  11  *      admit liability nor provide warranty for any of this software.
  12  *      This material is provided "AS-IS" and at no charge.
  13  *
  14  *      Release 1.1
  15  */
  16
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18
  19 #include <linux/module.h>
  20 #include <linux/types.h>
  21 #include <linux/miscdevice.h>
  22 #include <linux/watchdog.h>
  23 #include <linux/ioport.h>
  24 #include <linux/delay.h>
  25 #include <linux/notifier.h>
  26 #include <linux/fs.h>
  27 #include <linux/reboot.h>
  28 #include <linux/init.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/moduleparam.h>
  31 #include <linux/io.h>
  32 #include <linux/uaccess.h>
  33
  34
  35 /* #define DEBUG 1 */
  36
  37 #define DEFAULT_TIMEOUT     1           /* 1 minute */
  38 #define MAX_TIMEOUT         255
  39
  40 #define VERSION             "1.1"
  41 #define MODNAME             "pc87413 WDT"
  42 #define DPFX                MODNAME " - DEBUG: "
  43
  44 #define WDT_INDEX_IO_PORT   (io+0)      /* I/O port base (index register) */
  45 #define WDT_DATA_IO_PORT    (WDT_INDEX_IO_PORT+1)
  46 #define SWC_LDN             0x04
  47 #define SIOCFG2             0x22        /* Serial IO register */
  48 #define WDCTL               0x10        /* Watchdog-Timer-Control-Register */
  49 #define WDTO                0x11        /* Watchdog timeout register */
  50 #define WDCFG               0x12        /* Watchdog config register */
  51
  52 #define IO_DEFAULT      0x2E            /* Address used on Portwell Boards */
  53
  54 static int io = IO_DEFAULT;
  55 static int swc_base_addr = -1;
  56
  57 static int timeout = DEFAULT_TIMEOUT;   /* timeout value */
  58 static unsigned long timer_enabled;     /* is the timer enabled? */
  59
  60 static char expect_close;               /* is the close expected? */
  61
  62 static DEFINE_SPINLOCK(io_lock);        /* to guard us from io races */
  63
  64 static bool nowayout = WATCHDOG_NOWAYOUT;
  65
  66 /* -- Low level function ----------------------------------------*/
  67
  68 /* Select pins for Watchdog output */
  69
  70 static inline void pc87413_select_wdt_out(void)
  71 {
  72         unsigned int cr_data = 0;
  73
  74         /* Step 1: Select multiple pin,pin55,as WDT output */
  75
  76         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  77
  78         cr_data = inb(WDT_DATA_IO_PORT);
  79
  80         cr_data |= 0x80; /* Set Bit7 to 1*/
  81         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  82
  83         outb_p(cr_data, WDT_DATA_IO_PORT);
  84
  85 #ifdef DEBUG
  86         pr_info(DPFX
  87                 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
  88                                                                 cr_data);
  89 #endif
  90 }
  91
  92 /* Enable SWC functions */
  93
  94 static inline void pc87413_enable_swc(void)
  95 {
  96         unsigned int cr_data = 0;
  97
  98         /* Step 2: Enable SWC functions */
  99
 100         outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
 101         outb_p(SWC_LDN, WDT_DATA_IO_PORT);
 102
 103         outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
 104         cr_data = inb(WDT_DATA_IO_PORT);
 105         cr_data |= 0x01;                        /* Set Bit0 to 1 */
 106         outb_p(0x30, WDT_INDEX_IO_PORT);
 107         outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */
 108
 109 #ifdef DEBUG
 110         pr_info(DPFX "pc87413 - Enable SWC functions\n");
 111 #endif
 112 }
 113
 114 /* Read SWC I/O base address */
 115
 116 static void pc87413_get_swc_base_addr(void)
 117 {
 118         unsigned char addr_l, addr_h = 0;
 119
 120         /* Step 3: Read SWC I/O Base Address */
 121
 122         outb_p(0x60, WDT_INDEX_IO_PORT);        /* Read Index 0x60 */
 123         addr_h = inb(WDT_DATA_IO_PORT);
 124
 125         outb_p(0x61, WDT_INDEX_IO_PORT);        /* Read Index 0x61 */
 126
 127         addr_l = inb(WDT_DATA_IO_PORT);
 128
 129         swc_base_addr = (addr_h << 8) + addr_l;
 130 #ifdef DEBUG
 131         pr_info(DPFX
 132                 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
 133                                                 addr_l, addr_h, swc_base_addr);
 134 #endif
 135 }
 136
 137 /* Select Bank 3 of SWC */
 138
 139 static inline void pc87413_swc_bank3(void)
 140 {
 141         /* Step 4: Select Bank3 of SWC */
 142         outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
 143 #ifdef DEBUG
 144         pr_info(DPFX "Select Bank3 of SWC\n");
 145 #endif
 146 }
 147
 148 /* Set watchdog timeout to x minutes */
 149
 150 static inline void pc87413_programm_wdto(char pc87413_time)
 151 {
 152         /* Step 5: Programm WDTO, Twd. */
 153         outb_p(pc87413_time, swc_base_addr + WDTO);
 154 #ifdef DEBUG
 155         pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
 156 #endif
 157 }
 158
 159 /* Enable WDEN */
 160
 161 static inline void pc87413_enable_wden(void)
 162 {
 163         /* Step 6: Enable WDEN */
 164         outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
 165 #ifdef DEBUG
 166         pr_info(DPFX "Enable WDEN\n");
 167 #endif
 168 }
 169
 170 /* Enable SW_WD_TREN */
 171 static inline void pc87413_enable_sw_wd_tren(void)
 172 {
 173         /* Enable SW_WD_TREN */
 174         outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
 175 #ifdef DEBUG
 176         pr_info(DPFX "Enable SW_WD_TREN\n");
 177 #endif
 178 }
 179
 180 /* Disable SW_WD_TREN */
 181
 182 static inline void pc87413_disable_sw_wd_tren(void)
 183 {
 184         /* Disable SW_WD_TREN */
 185         outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
 186 #ifdef DEBUG
 187         pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
 188 #endif
 189 }
 190
 191 /* Enable SW_WD_TRG */
 192
 193 static inline void pc87413_enable_sw_wd_trg(void)
 194 {
 195         /* Enable SW_WD_TRG */
 196         outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
 197 #ifdef DEBUG
 198         pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
 199 #endif
 200 }
 201
 202 /* Disable SW_WD_TRG */
 203
 204 static inline void pc87413_disable_sw_wd_trg(void)
 205 {
 206         /* Disable SW_WD_TRG */
 207         outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
 208 #ifdef DEBUG
 209         pr_info(DPFX "Disable SW_WD_TRG\n");
 210 #endif
 211 }
 212
 213 /* -- Higher level functions ------------------------------------*/
 214
 215 /* Enable the watchdog */
 216
 217 static void pc87413_enable(void)
 218 {
 219         spin_lock(&io_lock);
 220
 221         pc87413_swc_bank3();
 222         pc87413_programm_wdto(timeout);
 223         pc87413_enable_wden();
 224         pc87413_enable_sw_wd_tren();
 225         pc87413_enable_sw_wd_trg();
 226
 227         spin_unlock(&io_lock);
 228 }
 229
 230 /* Disable the watchdog */
 231
 232 static void pc87413_disable(void)
 233 {
 234         spin_lock(&io_lock);
 235
 236         pc87413_swc_bank3();
 237         pc87413_disable_sw_wd_tren();
 238         pc87413_disable_sw_wd_trg();
 239         pc87413_programm_wdto(0);
 240
 241         spin_unlock(&io_lock);
 242 }
 243
 244 /* Refresh the watchdog */
 245
 246 static void pc87413_refresh(void)
 247 {
 248         spin_lock(&io_lock);
 249
 250         pc87413_swc_bank3();
 251         pc87413_disable_sw_wd_tren();
 252         pc87413_disable_sw_wd_trg();
 253         pc87413_programm_wdto(timeout);
 254         pc87413_enable_wden();
 255         pc87413_enable_sw_wd_tren();
 256         pc87413_enable_sw_wd_trg();
 257
 258         spin_unlock(&io_lock);
 259 }
 260
 261 /* -- File operations -------------------------------------------*/
 262
 263 /**
 264  *      pc87413_open:
 265  *      @inode: inode of device
 266  *      @file: file handle to device
 267  *
 268  */
 269
 270 static int pc87413_open(struct inode *inode, struct file *file)
 271 {
 272         /* /dev/watchdog can only be opened once */
 273
 274         if (test_and_set_bit(0, &timer_enabled))
 275                 return -EBUSY;
 276
 277         if (nowayout)
 278                 __module_get(THIS_MODULE);
 279
 280         /* Reload and activate timer */
 281         pc87413_refresh();
 282
 283         pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
 284
 285         return stream_open(inode, file);
 286 }
 287
 288 /**
 289  *      pc87413_release:
 290  *      @inode: inode to board
 291  *      @file: file handle to board
 292  *
 293  *      The watchdog has a configurable API. There is a religious dispute
 294  *      between people who want their watchdog to be able to shut down and
 295  *      those who want to be sure if the watchdog manager dies the machine
 296  *      reboots. In the former case we disable the counters, in the latter
 297  *      case you have to open it again very soon.
 298  */
 299
 300 static int pc87413_release(struct inode *inode, struct file *file)
 301 {
 302         /* Shut off the timer. */
 303
 304         if (expect_close == 42) {
 305                 pc87413_disable();
 306                 pr_info("Watchdog disabled, sleeping again...\n");
 307         } else {
 308                 pr_crit("Unexpected close, not stopping watchdog!\n");
 309                 pc87413_refresh();
 310         }
 311         clear_bit(0, &timer_enabled);
 312         expect_close = 0;
 313         return 0;
 314 }
 315
 316 /**
 317  *      pc87413_status:
 318  *
 319  *      return, if the watchdog is enabled (timeout is set...)
 320  */
 321
 322
 323 static int pc87413_status(void)
 324 {
 325           return 0; /* currently not supported */
 326 }
 327
 328 /**
 329  *      pc87413_write:
 330  *      @file: file handle to the watchdog
 331  *      @data: data buffer to write
 332  *      @len: length in bytes
 333  *      @ppos: pointer to the position to write. No seeks allowed
 334  *
 335  *      A write to a watchdog device is defined as a keepalive signal. Any
 336  *      write of data will do, as we we don't define content meaning.
 337  */
 338
 339 static ssize_t pc87413_write(struct file *file, const char __user *data,
 340                              size_t len, loff_t *ppos)
 341 {
 342         /* See if we got the magic character 'V' and reload the timer */
 343         if (len) {
 344                 if (!nowayout) {
 345                         size_t i;
 346
 347                         /* reset expect flag */
 348                         expect_close = 0;
 349
 350                         /* scan to see whether or not we got the
 351                            magic character */
 352                         for (i = 0; i != len; i++) {
 353                                 char c;
 354                                 if (get_user(c, data + i))
 355                                         return -EFAULT;
 356                                 if (c == 'V')
 357                                         expect_close = 42;
 358                         }
 359                 }
 360
 361                 /* someone wrote to us, we should reload the timer */
 362                 pc87413_refresh();
 363         }
 364         return len;
 365 }
 366
 367 /**
 368  *      pc87413_ioctl:
 369  *      @file: file handle to the device
 370  *      @cmd: watchdog command
 371  *      @arg: argument pointer
 372  *
 373  *      The watchdog API defines a common set of functions for all watchdogs
 374  *      according to their available features. We only actually usefully support
 375  *      querying capabilities and current status.
 376  */
 377
 378 static long pc87413_ioctl(struct file *file, unsigned int cmd,
 379                                                 unsigned long arg)
 380 {
 381         int new_timeout;
 382
 383         union {
 384                 struct watchdog_info __user *ident;
 385                 int __user *i;
 386         } uarg;
 387
 388         static const struct watchdog_info ident = {
 389                 .options          = WDIOF_KEEPALIVEPING |
 390                                     WDIOF_SETTIMEOUT |
 391                                     WDIOF_MAGICCLOSE,
 392                 .firmware_version = 1,
 393                 .identity         = "PC87413(HF/F) watchdog",
 394         };
 395
 396         uarg.i = (int __user *)arg;
 397
 398         switch (cmd) {
 399         case WDIOC_GETSUPPORT:
 400                 return copy_to_user(uarg.ident, &ident,
 401                                         sizeof(ident)) ? -EFAULT : 0;
 402         case WDIOC_GETSTATUS:
 403                 return put_user(pc87413_status(), uarg.i);
 404         case WDIOC_GETBOOTSTATUS:
 405                 return put_user(0, uarg.i);
 406         case WDIOC_SETOPTIONS:
 407         {
 408                 int options, retval = -EINVAL;
 409                 if (get_user(options, uarg.i))
 410                         return -EFAULT;
 411                 if (options & WDIOS_DISABLECARD) {
 412                         pc87413_disable();
 413                         retval = 0;
 414                 }
 415                 if (options & WDIOS_ENABLECARD) {
 416                         pc87413_enable();
 417                         retval = 0;
 418                 }
 419                 return retval;
 420         }
 421         case WDIOC_KEEPALIVE:
 422                 pc87413_refresh();
 423 #ifdef DEBUG
 424                 pr_info(DPFX "keepalive\n");
 425 #endif
 426                 return 0;
 427         case WDIOC_SETTIMEOUT:
 428                 if (get_user(new_timeout, uarg.i))
 429                         return -EFAULT;
 430                 /* the API states this is given in secs */
 431                 new_timeout /= 60;
 432                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 433                         return -EINVAL;
 434                 timeout = new_timeout;
 435                 pc87413_refresh();
 436                 fallthrough;    /* and return the new timeout */
 437         case WDIOC_GETTIMEOUT:
 438                 new_timeout = timeout * 60;
 439                 return put_user(new_timeout, uarg.i);
 440         default:
 441                 return -ENOTTY;
 442         }
 443 }
 444
 445 /* -- Notifier funtions -----------------------------------------*/
 446
 447 /**
 448  *      notify_sys:
 449  *      @this: our notifier block
 450  *      @code: the event being reported
 451  *      @unused: unused
 452  *
 453  *      Our notifier is called on system shutdowns. We want to turn the card
 454  *      off at reboot otherwise the machine will reboot again during memory
 455  *      test or worse yet during the following fsck. This would suck, in fact
 456  *      trust me - if it happens it does suck.
 457  */
 458
 459 static int pc87413_notify_sys(struct notifier_block *this,
 460                               unsigned long code,
 461                               void *unused)
 462 {
 463         if (code == SYS_DOWN || code == SYS_HALT)
 464                 /* Turn the card off */
 465                 pc87413_disable();
 466         return NOTIFY_DONE;
 467 }
 468
 469 /* -- Module's structures ---------------------------------------*/
 470
 471 static const struct file_operations pc87413_fops = {
 472         .owner          = THIS_MODULE,
 473         .llseek         = no_llseek,
 474         .write          = pc87413_write,
 475         .unlocked_ioctl = pc87413_ioctl,
 476         .compat_ioctl   = compat_ptr_ioctl,
 477         .open           = pc87413_open,
 478         .release        = pc87413_release,
 479 };
 480
 481 static struct notifier_block pc87413_notifier = {
 482         .notifier_call  = pc87413_notify_sys,
 483 };
 484
 485 static struct miscdevice pc87413_miscdev = {
 486         .minor          = WATCHDOG_MINOR,
 487         .name           = "watchdog",
 488         .fops           = &pc87413_fops,
 489 };
 490
 491 /* -- Module init functions -------------------------------------*/
 492
 493 /**
 494  *      pc87413_init: module's "constructor"
 495  *
 496  *      Set up the WDT watchdog board. All we have to do is grab the
 497  *      resources we require and bitch if anyone beat us to them.
 498  *      The open() function will actually kick the board off.
 499  */
 500
 501 static int __init pc87413_init(void)
 502 {
 503         int ret;
 504
 505         pr_info("Version " VERSION " at io 0x%X\n",
 506                                                         WDT_INDEX_IO_PORT);
 507
 508         if (!request_muxed_region(io, 2, MODNAME))
 509                 return -EBUSY;
 510
 511         ret = register_reboot_notifier(&pc87413_notifier);
 512         if (ret != 0)
 513                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
 514
 515         ret = misc_register(&pc87413_miscdev);
 516         if (ret != 0) {
 517                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 518                        WATCHDOG_MINOR, ret);
 519                 goto reboot_unreg;
 520         }
 521         pr_info("initialized. timeout=%d min\n", timeout);
 522
 523         pc87413_select_wdt_out();
 524         pc87413_enable_swc();
 525         pc87413_get_swc_base_addr();
 526
 527         if (!request_region(swc_base_addr, 0x20, MODNAME)) {
 528                 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
 529                 ret = -EBUSY;
 530                 goto misc_unreg;
 531         }
 532
 533         pc87413_enable();
 534
 535         release_region(io, 2);
 536         return 0;
 537
 538 misc_unreg:
 539         misc_deregister(&pc87413_miscdev);
 540 reboot_unreg:
 541         unregister_reboot_notifier(&pc87413_notifier);
 542         release_region(io, 2);
 543         return ret;
 544 }
 545
 546 /**
 547  *      pc87413_exit: module's "destructor"
 548  *
 549  *      Unload the watchdog. You cannot do this with any file handles open.
 550  *      If your watchdog is set to continue ticking on close and you unload
 551  *      it, well it keeps ticking. We won't get the interrupt but the board
 552  *      will not touch PC memory so all is fine. You just have to load a new
 553  *      module in 60 seconds or reboot.
 554  */
 555
 556 static void __exit pc87413_exit(void)
 557 {
 558         /* Stop the timer before we leave */
 559         if (!nowayout) {
 560                 pc87413_disable();
 561                 pr_info("Watchdog disabled\n");
 562         }
 563
 564         misc_deregister(&pc87413_miscdev);
 565         unregister_reboot_notifier(&pc87413_notifier);
 566         release_region(swc_base_addr, 0x20);
 567
 568         pr_info("watchdog component driver removed\n");
 569 }
 570
 571 module_init(pc87413_init);
 572 module_exit(pc87413_exit);
 573
 574 MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
 575 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");
 576 MODULE_DESCRIPTION("PC87413 WDT driver");
 577 MODULE_LICENSE("GPL");
 578
 579 module_param_hw(io, int, ioport, 0);
 580 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
 581                                         __MODULE_STRING(IO_DEFAULT) ").");
 582
 583 module_param(timeout, int, 0);
 584 MODULE_PARM_DESC(timeout,
 585                 "Watchdog timeout in minutes (default="
 586                                 __MODULE_STRING(DEFAULT_TIMEOUT) ").");
 587
 588 module_param(nowayout, bool, 0);
 589 MODULE_PARM_DESC(nowayout,
 590                 "Watchdog cannot be stopped once started (default="
 591                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 592