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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip4 *5 * (c) Copyright 2005 Jose Goncalves <jose.goncalves@inov.pt>6 *7 * Based on w83877f_wdt.c by Scott Jennings,8 * and wdt977.c by Woody Suwalski9 *10 * -----------------------11 */12 13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt14 15#include <linux/module.h>16#include <linux/moduleparam.h>17#include <linux/types.h>18#include <linux/kernel.h>19#include <linux/fs.h>20#include <linux/miscdevice.h>21#include <linux/init.h>22#include <linux/ioport.h>23#include <linux/watchdog.h>24#include <linux/notifier.h>25#include <linux/reboot.h>26#include <linux/uaccess.h>27#include <linux/io.h>28 29 30#define WATCHDOG_VERSION "1.00"31#define WATCHDOG_NAME "W83977F WDT"32 33#define IO_INDEX_PORT 0x3F034#define IO_DATA_PORT (IO_INDEX_PORT+1)35 36#define UNLOCK_DATA 0x8737#define LOCK_DATA 0xAA38#define DEVICE_REGISTER 0x0739 40#define DEFAULT_TIMEOUT 45 /* default timeout in seconds */41 42static int timeout = DEFAULT_TIMEOUT;43static int timeoutW; /* timeout in watchdog counter units */44static unsigned long timer_alive;45static int testmode;46static char expect_close;47static DEFINE_SPINLOCK(spinlock);48 49module_param(timeout, int, 0);50MODULE_PARM_DESC(timeout,51 "Watchdog timeout in seconds (15..7635), default="52 __MODULE_STRING(DEFAULT_TIMEOUT) ")");53module_param(testmode, int, 0);54MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");55 56static bool nowayout = WATCHDOG_NOWAYOUT;57module_param(nowayout, bool, 0);58MODULE_PARM_DESC(nowayout,59 "Watchdog cannot be stopped once started (default="60 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");61 62/*63 * Start the watchdog64 */65 66static int wdt_start(void)67{68 unsigned long flags;69 70 spin_lock_irqsave(&spinlock, flags);71 72 /* Unlock the SuperIO chip */73 outb_p(UNLOCK_DATA, IO_INDEX_PORT);74 outb_p(UNLOCK_DATA, IO_INDEX_PORT);75 76 /*77 * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.78 * F2 has the timeout in watchdog counter units.79 * F3 is set to enable watchdog LED blink at timeout.80 * F4 is used to just clear the TIMEOUT'ed state (bit 0).81 */82 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);83 outb_p(0x08, IO_DATA_PORT);84 outb_p(0xF2, IO_INDEX_PORT);85 outb_p(timeoutW, IO_DATA_PORT);86 outb_p(0xF3, IO_INDEX_PORT);87 outb_p(0x08, IO_DATA_PORT);88 outb_p(0xF4, IO_INDEX_PORT);89 outb_p(0x00, IO_DATA_PORT);90 91 /* Set device Aux2 active */92 outb_p(0x30, IO_INDEX_PORT);93 outb_p(0x01, IO_DATA_PORT);94 95 /*96 * Select device Aux1 (dev=7) to set GP16 as the watchdog output97 * (in reg E6) and GP13 as the watchdog LED output (in reg E3).98 * Map GP16 at pin 119.99 * In test mode watch the bit 0 on F4 to indicate "triggered" or100 * check watchdog LED on SBC.101 */102 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);103 outb_p(0x07, IO_DATA_PORT);104 if (!testmode) {105 unsigned pin_map;106 107 outb_p(0xE6, IO_INDEX_PORT);108 outb_p(0x0A, IO_DATA_PORT);109 outb_p(0x2C, IO_INDEX_PORT);110 pin_map = inb_p(IO_DATA_PORT);111 pin_map |= 0x10;112 pin_map &= ~(0x20);113 outb_p(0x2C, IO_INDEX_PORT);114 outb_p(pin_map, IO_DATA_PORT);115 }116 outb_p(0xE3, IO_INDEX_PORT);117 outb_p(0x08, IO_DATA_PORT);118 119 /* Set device Aux1 active */120 outb_p(0x30, IO_INDEX_PORT);121 outb_p(0x01, IO_DATA_PORT);122 123 /* Lock the SuperIO chip */124 outb_p(LOCK_DATA, IO_INDEX_PORT);125 126 spin_unlock_irqrestore(&spinlock, flags);127 128 pr_info("activated\n");129 130 return 0;131}132 133/*134 * Stop the watchdog135 */136 137static int wdt_stop(void)138{139 unsigned long flags;140 141 spin_lock_irqsave(&spinlock, flags);142 143 /* Unlock the SuperIO chip */144 outb_p(UNLOCK_DATA, IO_INDEX_PORT);145 outb_p(UNLOCK_DATA, IO_INDEX_PORT);146 147 /*148 * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.149 * F2 is reset to its default value (watchdog timer disabled).150 * F3 is reset to its default state.151 * F4 clears the TIMEOUT'ed state (bit 0) - back to default.152 */153 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);154 outb_p(0x08, IO_DATA_PORT);155 outb_p(0xF2, IO_INDEX_PORT);156 outb_p(0xFF, IO_DATA_PORT);157 outb_p(0xF3, IO_INDEX_PORT);158 outb_p(0x00, IO_DATA_PORT);159 outb_p(0xF4, IO_INDEX_PORT);160 outb_p(0x00, IO_DATA_PORT);161 outb_p(0xF2, IO_INDEX_PORT);162 outb_p(0x00, IO_DATA_PORT);163 164 /*165 * Select device Aux1 (dev=7) to set GP16 (in reg E6) and166 * Gp13 (in reg E3) as inputs.167 */168 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);169 outb_p(0x07, IO_DATA_PORT);170 if (!testmode) {171 outb_p(0xE6, IO_INDEX_PORT);172 outb_p(0x01, IO_DATA_PORT);173 }174 outb_p(0xE3, IO_INDEX_PORT);175 outb_p(0x01, IO_DATA_PORT);176 177 /* Lock the SuperIO chip */178 outb_p(LOCK_DATA, IO_INDEX_PORT);179 180 spin_unlock_irqrestore(&spinlock, flags);181 182 pr_info("shutdown\n");183 184 return 0;185}186 187/*188 * Send a keepalive ping to the watchdog189 * This is done by simply re-writing the timeout to reg. 0xF2190 */191 192static int wdt_keepalive(void)193{194 unsigned long flags;195 196 spin_lock_irqsave(&spinlock, flags);197 198 /* Unlock the SuperIO chip */199 outb_p(UNLOCK_DATA, IO_INDEX_PORT);200 outb_p(UNLOCK_DATA, IO_INDEX_PORT);201 202 /* Select device Aux2 (device=8) to kick watchdog reg F2 */203 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);204 outb_p(0x08, IO_DATA_PORT);205 outb_p(0xF2, IO_INDEX_PORT);206 outb_p(timeoutW, IO_DATA_PORT);207 208 /* Lock the SuperIO chip */209 outb_p(LOCK_DATA, IO_INDEX_PORT);210 211 spin_unlock_irqrestore(&spinlock, flags);212 213 return 0;214}215 216/*217 * Set the watchdog timeout value218 */219 220static int wdt_set_timeout(int t)221{222 unsigned int tmrval;223 224 /*225 * Convert seconds to watchdog counter time units, rounding up.226 * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup227 * value. This information is supplied in the PCM-5335 manual and was228 * checked by me on a real board. This is a bit strange because W83977f229 * datasheet says counter unit is in minutes!230 */231 if (t < 15)232 return -EINVAL;233 234 tmrval = ((t + 15) + 29) / 30;235 236 if (tmrval > 255)237 return -EINVAL;238 239 /*240 * timeout is the timeout in seconds,241 * timeoutW is the timeout in watchdog counter units.242 */243 timeoutW = tmrval;244 timeout = (timeoutW * 30) - 15;245 return 0;246}247 248/*249 * Get the watchdog status250 */251 252static int wdt_get_status(int *status)253{254 int new_status;255 unsigned long flags;256 257 spin_lock_irqsave(&spinlock, flags);258 259 /* Unlock the SuperIO chip */260 outb_p(UNLOCK_DATA, IO_INDEX_PORT);261 outb_p(UNLOCK_DATA, IO_INDEX_PORT);262 263 /* Select device Aux2 (device=8) to read watchdog reg F4 */264 outb_p(DEVICE_REGISTER, IO_INDEX_PORT);265 outb_p(0x08, IO_DATA_PORT);266 outb_p(0xF4, IO_INDEX_PORT);267 new_status = inb_p(IO_DATA_PORT);268 269 /* Lock the SuperIO chip */270 outb_p(LOCK_DATA, IO_INDEX_PORT);271 272 spin_unlock_irqrestore(&spinlock, flags);273 274 *status = 0;275 if (new_status & 1)276 *status |= WDIOF_CARDRESET;277 278 return 0;279}280 281 282/*283 * /dev/watchdog handling284 */285 286static int wdt_open(struct inode *inode, struct file *file)287{288 /* If the watchdog is alive we don't need to start it again */289 if (test_and_set_bit(0, &timer_alive))290 return -EBUSY;291 292 if (nowayout)293 __module_get(THIS_MODULE);294 295 wdt_start();296 return stream_open(inode, file);297}298 299static int wdt_release(struct inode *inode, struct file *file)300{301 /*302 * Shut off the timer.303 * Lock it in if it's a module and we set nowayout304 */305 if (expect_close == 42) {306 wdt_stop();307 clear_bit(0, &timer_alive);308 } else {309 wdt_keepalive();310 pr_crit("unexpected close, not stopping watchdog!\n");311 }312 expect_close = 0;313 return 0;314}315 316/*317 * wdt_write:318 * @file: file handle to the watchdog319 * @buf: buffer to write (unused as data does not matter here320 * @count: count of bytes321 * @ppos: pointer to the position to write. No seeks allowed322 *323 * A write to a watchdog device is defined as a keepalive signal. Any324 * write of data will do, as we don't define content meaning.325 */326 327static ssize_t wdt_write(struct file *file, const char __user *buf,328 size_t count, loff_t *ppos)329{330 /* See if we got the magic character 'V' and reload the timer */331 if (count) {332 if (!nowayout) {333 size_t ofs;334 335 /* note: just in case someone wrote the336 magic character long ago */337 expect_close = 0;338 339 /* scan to see whether or not we got the340 magic character */341 for (ofs = 0; ofs != count; ofs++) {342 char c;343 if (get_user(c, buf + ofs))344 return -EFAULT;345 if (c == 'V')346 expect_close = 42;347 }348 }349 350 /* someone wrote to us, we should restart timer */351 wdt_keepalive();352 }353 return count;354}355 356/*357 * wdt_ioctl:358 * @inode: inode of the device359 * @file: file handle to the device360 * @cmd: watchdog command361 * @arg: argument pointer362 *363 * The watchdog API defines a common set of functions for all watchdogs364 * according to their available features.365 */366 367static const struct watchdog_info ident = {368 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,369 .firmware_version = 1,370 .identity = WATCHDOG_NAME,371};372 373static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)374{375 int status;376 int new_options, retval = -EINVAL;377 int new_timeout;378 union {379 struct watchdog_info __user *ident;380 int __user *i;381 } uarg;382 383 uarg.i = (int __user *)arg;384 385 switch (cmd) {386 case WDIOC_GETSUPPORT:387 return copy_to_user(uarg.ident, &ident,388 sizeof(ident)) ? -EFAULT : 0;389 390 case WDIOC_GETSTATUS:391 wdt_get_status(&status);392 return put_user(status, uarg.i);393 394 case WDIOC_GETBOOTSTATUS:395 return put_user(0, uarg.i);396 397 case WDIOC_SETOPTIONS:398 if (get_user(new_options, uarg.i))399 return -EFAULT;400 401 if (new_options & WDIOS_DISABLECARD) {402 wdt_stop();403 retval = 0;404 }405 406 if (new_options & WDIOS_ENABLECARD) {407 wdt_start();408 retval = 0;409 }410 411 return retval;412 413 case WDIOC_KEEPALIVE:414 wdt_keepalive();415 return 0;416 417 case WDIOC_SETTIMEOUT:418 if (get_user(new_timeout, uarg.i))419 return -EFAULT;420 421 if (wdt_set_timeout(new_timeout))422 return -EINVAL;423 424 wdt_keepalive();425 fallthrough;426 427 case WDIOC_GETTIMEOUT:428 return put_user(timeout, uarg.i);429 430 default:431 return -ENOTTY;432 433 }434}435 436static int wdt_notify_sys(struct notifier_block *this, unsigned long code,437 void *unused)438{439 if (code == SYS_DOWN || code == SYS_HALT)440 wdt_stop();441 return NOTIFY_DONE;442}443 444static const struct file_operations wdt_fops = {445 .owner = THIS_MODULE,446 .write = wdt_write,447 .unlocked_ioctl = wdt_ioctl,448 .compat_ioctl = compat_ptr_ioctl,449 .open = wdt_open,450 .release = wdt_release,451};452 453static struct miscdevice wdt_miscdev = {454 .minor = WATCHDOG_MINOR,455 .name = "watchdog",456 .fops = &wdt_fops,457};458 459static struct notifier_block wdt_notifier = {460 .notifier_call = wdt_notify_sys,461};462 463static int __init w83977f_wdt_init(void)464{465 int rc;466 467 pr_info("driver v%s\n", WATCHDOG_VERSION);468 469 /*470 * Check that the timeout value is within it's range;471 * if not reset to the default472 */473 if (wdt_set_timeout(timeout)) {474 wdt_set_timeout(DEFAULT_TIMEOUT);475 pr_info("timeout value must be 15 <= timeout <= 7635, using %d\n",476 DEFAULT_TIMEOUT);477 }478 479 if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {480 pr_err("I/O address 0x%04x already in use\n", IO_INDEX_PORT);481 rc = -EIO;482 goto err_out;483 }484 485 rc = register_reboot_notifier(&wdt_notifier);486 if (rc) {487 pr_err("cannot register reboot notifier (err=%d)\n", rc);488 goto err_out_region;489 }490 491 rc = misc_register(&wdt_miscdev);492 if (rc) {493 pr_err("cannot register miscdev on minor=%d (err=%d)\n",494 wdt_miscdev.minor, rc);495 goto err_out_reboot;496 }497 498 pr_info("initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",499 timeout, nowayout, testmode);500 501 return 0;502 503err_out_reboot:504 unregister_reboot_notifier(&wdt_notifier);505err_out_region:506 release_region(IO_INDEX_PORT, 2);507err_out:508 return rc;509}510 511static void __exit w83977f_wdt_exit(void)512{513 wdt_stop();514 misc_deregister(&wdt_miscdev);515 unregister_reboot_notifier(&wdt_notifier);516 release_region(IO_INDEX_PORT, 2);517}518 519module_init(w83977f_wdt_init);520module_exit(w83977f_wdt_exit);521 522MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");523MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");524MODULE_LICENSE("GPL");525