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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * ALi M7101 PMU Computer Watchdog Timer driver4 *5 * Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>6 * and the Cobalt kernel WDT timer driver by Tim Hockin7 * <thockin@cobaltnet.com>8 *9 * (c)2002 Steve Hill <steve@navaho.co.uk>10 *11 * This WDT driver is different from most other Linux WDT12 * drivers in that the driver will ping the watchdog by itself,13 * because this particular WDT has a very short timeout (1.614 * seconds) and it would be insane to count on any userspace15 * daemon always getting scheduled within that time frame.16 *17 * Additions:18 * Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs19 * found on very old cobalt hardware.20 * -- Mike Waychison <michael.waychison@sun.com>21 */22 23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt24 25#include <linux/module.h>26#include <linux/moduleparam.h>27#include <linux/types.h>28#include <linux/timer.h>29#include <linux/miscdevice.h>30#include <linux/watchdog.h>31#include <linux/ioport.h>32#include <linux/notifier.h>33#include <linux/reboot.h>34#include <linux/init.h>35#include <linux/fs.h>36#include <linux/pci.h>37#include <linux/io.h>38#include <linux/uaccess.h>39 40 41#define WDT_ENABLE 0x9C42#define WDT_DISABLE 0x8C43 44#define ALI_7101_WDT 0x9245#define ALI_7101_GPIO 0x7D46#define ALI_7101_GPIO_O 0x7E47#define ALI_WDT_ARM 0x0148 49/*50 * We're going to use a 1 second timeout.51 * If we reset the watchdog every ~250ms we should be safe. */52 53#define WDT_INTERVAL (HZ/4+1)54 55/*56 * We must not require too good response from the userspace daemon.57 * Here we require the userspace daemon to send us a heartbeat58 * char to /dev/watchdog every 30 seconds.59 */60 61#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */62/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */63static int timeout = WATCHDOG_TIMEOUT;64module_param(timeout, int, 0);65MODULE_PARM_DESC(timeout,66 "Watchdog timeout in seconds. (1<=timeout<=3600, default="67 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");68 69static int use_gpio; /* Use the pic (for a1d revision alim7101) */70module_param(use_gpio, int, 0);71MODULE_PARM_DESC(use_gpio,72 "Use the gpio watchdog (required by old cobalt boards).");73 74static void wdt_timer_ping(struct timer_list *);75static DEFINE_TIMER(timer, wdt_timer_ping);76static unsigned long next_heartbeat;77static unsigned long wdt_is_open;78static char wdt_expect_close;79static struct pci_dev *alim7101_pmu;80 81static bool nowayout = WATCHDOG_NOWAYOUT;82module_param(nowayout, bool, 0);83MODULE_PARM_DESC(nowayout,84 "Watchdog cannot be stopped once started (default="85 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");86 87/*88 * Whack the dog89 */90 91static void wdt_timer_ping(struct timer_list *unused)92{93 /* If we got a heartbeat pulse within the WDT_US_INTERVAL94 * we agree to ping the WDT95 */96 char tmp;97 98 if (time_before(jiffies, next_heartbeat)) {99 /* Ping the WDT (this is actually a disarm/arm sequence) */100 pci_read_config_byte(alim7101_pmu, 0x92, &tmp);101 pci_write_config_byte(alim7101_pmu,102 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));103 pci_write_config_byte(alim7101_pmu,104 ALI_7101_WDT, (tmp | ALI_WDT_ARM));105 if (use_gpio) {106 pci_read_config_byte(alim7101_pmu,107 ALI_7101_GPIO_O, &tmp);108 pci_write_config_byte(alim7101_pmu,109 ALI_7101_GPIO_O, tmp | 0x20);110 pci_write_config_byte(alim7101_pmu,111 ALI_7101_GPIO_O, tmp & ~0x20);112 }113 } else {114 pr_warn("Heartbeat lost! Will not ping the watchdog\n");115 }116 /* Re-set the timer interval */117 mod_timer(&timer, jiffies + WDT_INTERVAL);118}119 120/*121 * Utility routines122 */123 124static void wdt_change(int writeval)125{126 char tmp;127 128 pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);129 if (writeval == WDT_ENABLE) {130 pci_write_config_byte(alim7101_pmu,131 ALI_7101_WDT, (tmp | ALI_WDT_ARM));132 if (use_gpio) {133 pci_read_config_byte(alim7101_pmu,134 ALI_7101_GPIO_O, &tmp);135 pci_write_config_byte(alim7101_pmu,136 ALI_7101_GPIO_O, tmp & ~0x20);137 }138 139 } else {140 pci_write_config_byte(alim7101_pmu,141 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));142 if (use_gpio) {143 pci_read_config_byte(alim7101_pmu,144 ALI_7101_GPIO_O, &tmp);145 pci_write_config_byte(alim7101_pmu,146 ALI_7101_GPIO_O, tmp | 0x20);147 }148 }149}150 151static void wdt_startup(void)152{153 next_heartbeat = jiffies + (timeout * HZ);154 155 /* We must enable before we kick off the timer in case the timer156 occurs as we ping it */157 158 wdt_change(WDT_ENABLE);159 160 /* Start the timer */161 mod_timer(&timer, jiffies + WDT_INTERVAL);162 163 pr_info("Watchdog timer is now enabled\n");164}165 166static void wdt_turnoff(void)167{168 /* Stop the timer */169 del_timer_sync(&timer);170 wdt_change(WDT_DISABLE);171 pr_info("Watchdog timer is now disabled...\n");172}173 174static void wdt_keepalive(void)175{176 /* user land ping */177 next_heartbeat = jiffies + (timeout * HZ);178}179 180/*181 * /dev/watchdog handling182 */183 184static ssize_t fop_write(struct file *file, const char __user *buf,185 size_t count, loff_t *ppos)186{187 /* See if we got the magic character 'V' and reload the timer */188 if (count) {189 if (!nowayout) {190 size_t ofs;191 192 /* note: just in case someone wrote the magic character193 * five months ago... */194 wdt_expect_close = 0;195 196 /* now scan */197 for (ofs = 0; ofs != count; ofs++) {198 char c;199 if (get_user(c, buf + ofs))200 return -EFAULT;201 if (c == 'V')202 wdt_expect_close = 42;203 }204 }205 /* someone wrote to us, we should restart timer */206 wdt_keepalive();207 }208 return count;209}210 211static int fop_open(struct inode *inode, struct file *file)212{213 /* Just in case we're already talking to someone... */214 if (test_and_set_bit(0, &wdt_is_open))215 return -EBUSY;216 /* Good, fire up the show */217 wdt_startup();218 return stream_open(inode, file);219}220 221static int fop_close(struct inode *inode, struct file *file)222{223 if (wdt_expect_close == 42)224 wdt_turnoff();225 else {226 /* wim: shouldn't there be a: del_timer(&timer); */227 pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");228 }229 clear_bit(0, &wdt_is_open);230 wdt_expect_close = 0;231 return 0;232}233 234static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)235{236 void __user *argp = (void __user *)arg;237 int __user *p = argp;238 static const struct watchdog_info ident = {239 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT240 | WDIOF_MAGICCLOSE,241 .firmware_version = 1,242 .identity = "ALiM7101",243 };244 245 switch (cmd) {246 case WDIOC_GETSUPPORT:247 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;248 case WDIOC_GETSTATUS:249 case WDIOC_GETBOOTSTATUS:250 return put_user(0, p);251 case WDIOC_SETOPTIONS:252 {253 int new_options, retval = -EINVAL;254 255 if (get_user(new_options, p))256 return -EFAULT;257 if (new_options & WDIOS_DISABLECARD) {258 wdt_turnoff();259 retval = 0;260 }261 if (new_options & WDIOS_ENABLECARD) {262 wdt_startup();263 retval = 0;264 }265 return retval;266 }267 case WDIOC_KEEPALIVE:268 wdt_keepalive();269 return 0;270 case WDIOC_SETTIMEOUT:271 {272 int new_timeout;273 274 if (get_user(new_timeout, p))275 return -EFAULT;276 /* arbitrary upper limit */277 if (new_timeout < 1 || new_timeout > 3600)278 return -EINVAL;279 timeout = new_timeout;280 wdt_keepalive();281 }282 fallthrough;283 case WDIOC_GETTIMEOUT:284 return put_user(timeout, p);285 default:286 return -ENOTTY;287 }288}289 290static const struct file_operations wdt_fops = {291 .owner = THIS_MODULE,292 .write = fop_write,293 .open = fop_open,294 .release = fop_close,295 .unlocked_ioctl = fop_ioctl,296 .compat_ioctl = compat_ptr_ioctl,297};298 299static struct miscdevice wdt_miscdev = {300 .minor = WATCHDOG_MINOR,301 .name = "watchdog",302 .fops = &wdt_fops,303};304 305static int wdt_restart_handle(struct notifier_block *this, unsigned long mode,306 void *cmd)307{308 /*309 * Cobalt devices have no way of rebooting themselves other310 * than getting the watchdog to pull reset, so we restart the311 * watchdog on reboot with no heartbeat.312 */313 wdt_change(WDT_ENABLE);314 315 /* loop until the watchdog fires */316 while (true)317 ;318 319 return NOTIFY_DONE;320}321 322static struct notifier_block wdt_restart_handler = {323 .notifier_call = wdt_restart_handle,324 .priority = 128,325};326 327/*328 * Notifier for system down329 */330 331static int wdt_notify_sys(struct notifier_block *this,332 unsigned long code, void *unused)333{334 if (code == SYS_DOWN || code == SYS_HALT)335 wdt_turnoff();336 337 return NOTIFY_DONE;338}339 340/*341 * The WDT needs to learn about soft shutdowns in order to342 * turn the timebomb registers off.343 */344 345static struct notifier_block wdt_notifier = {346 .notifier_call = wdt_notify_sys,347};348 349static void __exit alim7101_wdt_unload(void)350{351 wdt_turnoff();352 /* Deregister */353 misc_deregister(&wdt_miscdev);354 unregister_reboot_notifier(&wdt_notifier);355 unregister_restart_handler(&wdt_restart_handler);356 pci_dev_put(alim7101_pmu);357}358 359static int __init alim7101_wdt_init(void)360{361 int rc = -EBUSY;362 struct pci_dev *ali1543_south;363 char tmp;364 365 pr_info("Steve Hill <steve@navaho.co.uk>\n");366 alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,367 NULL);368 if (!alim7101_pmu) {369 pr_info("ALi M7101 PMU not present - WDT not set\n");370 return -EBUSY;371 }372 373 /* Set the WDT in the PMU to 1 second */374 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);375 376 ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,377 NULL);378 if (!ali1543_south) {379 pr_info("ALi 1543 South-Bridge not present - WDT not set\n");380 goto err_out;381 }382 pci_read_config_byte(ali1543_south, 0x5e, &tmp);383 pci_dev_put(ali1543_south);384 if ((tmp & 0x1e) == 0x00) {385 if (!use_gpio) {386 pr_info("Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n");387 goto err_out;388 }389 nowayout = 1;390 } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {391 pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");392 goto err_out;393 }394 395 if (timeout < 1 || timeout > 3600) {396 /* arbitrary upper limit */397 timeout = WATCHDOG_TIMEOUT;398 pr_info("timeout value must be 1 <= x <= 3600, using %d\n",399 timeout);400 }401 402 rc = register_reboot_notifier(&wdt_notifier);403 if (rc) {404 pr_err("cannot register reboot notifier (err=%d)\n", rc);405 goto err_out;406 }407 408 rc = register_restart_handler(&wdt_restart_handler);409 if (rc) {410 pr_err("cannot register restart handler (err=%d)\n", rc);411 goto err_out_reboot;412 }413 414 rc = misc_register(&wdt_miscdev);415 if (rc) {416 pr_err("cannot register miscdev on minor=%d (err=%d)\n",417 wdt_miscdev.minor, rc);418 goto err_out_restart;419 }420 421 if (nowayout)422 __module_get(THIS_MODULE);423 424 pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",425 timeout, nowayout);426 return 0;427 428err_out_restart:429 unregister_restart_handler(&wdt_restart_handler);430err_out_reboot:431 unregister_reboot_notifier(&wdt_notifier);432err_out:433 pci_dev_put(alim7101_pmu);434 return rc;435}436 437module_init(alim7101_wdt_init);438module_exit(alim7101_wdt_unload);439 440static const struct pci_device_id alim7101_pci_tbl[] __used = {441 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },442 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },443 { }444};445 446MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);447 448MODULE_AUTHOR("Steve Hill");449MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");450MODULE_LICENSE("GPL");451