592 lines · c
1// SPDX-License-Identifier: GPL-2.0+2/*3 * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x4 *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 AG11 * admit liability nor provide warranty for any of this software.12 * This material is provided "AS-IS" and at no charge.13 *14 * Release 1.115 */16 17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt18 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 25539 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 0x0447#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 54static int io = IO_DEFAULT;55static int swc_base_addr = -1;56 57static int timeout = DEFAULT_TIMEOUT; /* timeout value */58static unsigned long timer_enabled; /* is the timer enabled? */59 60static char expect_close; /* is the close expected? */61 62static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */63 64static bool nowayout = WATCHDOG_NOWAYOUT;65 66/* -- Low level function ----------------------------------------*/67 68/* Select pins for Watchdog output */69 70static 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 DEBUG86 pr_info(DPFX87 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",88 cr_data);89#endif90}91 92/* Enable SWC functions */93 94static 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 DEBUG110 pr_info(DPFX "pc87413 - Enable SWC functions\n");111#endif112}113 114/* Read SWC I/O base address */115 116static 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 DEBUG131 pr_info(DPFX132 "Read SWC I/O Base Address: low %d, high %d, res %d\n",133 addr_l, addr_h, swc_base_addr);134#endif135}136 137/* Select Bank 3 of SWC */138 139static 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 DEBUG144 pr_info(DPFX "Select Bank3 of SWC\n");145#endif146}147 148/* Set watchdog timeout to x minutes */149 150static 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 DEBUG155 pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);156#endif157}158 159/* Enable WDEN */160 161static 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 DEBUG166 pr_info(DPFX "Enable WDEN\n");167#endif168}169 170/* Enable SW_WD_TREN */171static 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 DEBUG176 pr_info(DPFX "Enable SW_WD_TREN\n");177#endif178}179 180/* Disable SW_WD_TREN */181 182static 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 DEBUG187 pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");188#endif189}190 191/* Enable SW_WD_TRG */192 193static 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 DEBUG198 pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");199#endif200}201 202/* Disable SW_WD_TRG */203 204static 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 DEBUG209 pr_info(DPFX "Disable SW_WD_TRG\n");210#endif211}212 213/* -- Higher level functions ------------------------------------*/214 215/* Enable the watchdog */216 217static 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 232static 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 246static 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 device266 * @file: file handle to device267 *268 */269 270static 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 board291 * @file: file handle to board292 *293 * The watchdog has a configurable API. There is a religious dispute294 * between people who want their watchdog to be able to shut down and295 * those who want to be sure if the watchdog manager dies the machine296 * reboots. In the former case we disable the counters, in the latter297 * case you have to open it again very soon.298 */299 300static 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 323static int pc87413_status(void)324{325 return 0; /* currently not supported */326}327 328/**329 * pc87413_write:330 * @file: file handle to the watchdog331 * @data: data buffer to write332 * @len: length in bytes333 * @ppos: pointer to the position to write. No seeks allowed334 *335 * A write to a watchdog device is defined as a keepalive signal. Any336 * write of data will do, as we we don't define content meaning.337 */338 339static 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 the351 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 device370 * @cmd: watchdog command371 * @arg: argument pointer372 *373 * The watchdog API defines a common set of functions for all watchdogs374 * according to their available features. We only actually usefully support375 * querying capabilities and current status.376 */377 378static 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 DEBUG424 pr_info(DPFX "keepalive\n");425#endif426 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 functions -----------------------------------------*/446 447/**448 * pc87413_notify_sys:449 * @this: our notifier block450 * @code: the event being reported451 * @unused: unused452 *453 * Our notifier is called on system shutdowns. We want to turn the card454 * off at reboot otherwise the machine will reboot again during memory455 * test or worse yet during the following fsck. This would suck, in fact456 * trust me - if it happens it does suck.457 */458 459static 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 471static const struct file_operations pc87413_fops = {472 .owner = THIS_MODULE,473 .write = pc87413_write,474 .unlocked_ioctl = pc87413_ioctl,475 .compat_ioctl = compat_ptr_ioctl,476 .open = pc87413_open,477 .release = pc87413_release,478};479 480static struct notifier_block pc87413_notifier = {481 .notifier_call = pc87413_notify_sys,482};483 484static struct miscdevice pc87413_miscdev = {485 .minor = WATCHDOG_MINOR,486 .name = "watchdog",487 .fops = &pc87413_fops,488};489 490/* -- Module init functions -------------------------------------*/491 492/**493 * pc87413_init: module's "constructor"494 *495 * Set up the WDT watchdog board. All we have to do is grab the496 * resources we require and bitch if anyone beat us to them.497 * The open() function will actually kick the board off.498 */499 500static int __init pc87413_init(void)501{502 int ret;503 504 pr_info("Version " VERSION " at io 0x%X\n",505 WDT_INDEX_IO_PORT);506 507 if (!request_muxed_region(io, 2, MODNAME))508 return -EBUSY;509 510 ret = register_reboot_notifier(&pc87413_notifier);511 if (ret != 0)512 pr_err("cannot register reboot notifier (err=%d)\n", ret);513 514 ret = misc_register(&pc87413_miscdev);515 if (ret != 0) {516 pr_err("cannot register miscdev on minor=%d (err=%d)\n",517 WATCHDOG_MINOR, ret);518 goto reboot_unreg;519 }520 pr_info("initialized. timeout=%d min\n", timeout);521 522 pc87413_select_wdt_out();523 pc87413_enable_swc();524 pc87413_get_swc_base_addr();525 526 if (!request_region(swc_base_addr, 0x20, MODNAME)) {527 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);528 ret = -EBUSY;529 goto misc_unreg;530 }531 532 pc87413_enable();533 534 release_region(io, 2);535 return 0;536 537misc_unreg:538 misc_deregister(&pc87413_miscdev);539reboot_unreg:540 unregister_reboot_notifier(&pc87413_notifier);541 release_region(io, 2);542 return ret;543}544 545/**546 * pc87413_exit: module's "destructor"547 *548 * Unload the watchdog. You cannot do this with any file handles open.549 * If your watchdog is set to continue ticking on close and you unload550 * it, well it keeps ticking. We won't get the interrupt but the board551 * will not touch PC memory so all is fine. You just have to load a new552 * module in 60 seconds or reboot.553 */554 555static void __exit pc87413_exit(void)556{557 /* Stop the timer before we leave */558 if (!nowayout) {559 pc87413_disable();560 pr_info("Watchdog disabled\n");561 }562 563 misc_deregister(&pc87413_miscdev);564 unregister_reboot_notifier(&pc87413_notifier);565 release_region(swc_base_addr, 0x20);566 567 pr_info("watchdog component driver removed\n");568}569 570module_init(pc87413_init);571module_exit(pc87413_exit);572 573MODULE_AUTHOR("Sven Anders <anders@anduras.de>");574MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");575MODULE_DESCRIPTION("PC87413 WDT driver");576MODULE_LICENSE("GPL");577 578module_param_hw(io, int, ioport, 0);579MODULE_PARM_DESC(io, MODNAME " I/O port (default: "580 __MODULE_STRING(IO_DEFAULT) ").");581 582module_param(timeout, int, 0);583MODULE_PARM_DESC(timeout,584 "Watchdog timeout in minutes (default="585 __MODULE_STRING(DEFAULT_TIMEOUT) ").");586 587module_param(nowayout, bool, 0);588MODULE_PARM_DESC(nowayout,589 "Watchdog cannot be stopped once started (default="590 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");591 592