// SPDX-License-Identifier: GPL-2.0+ /* * Advantech Single Board Computer WDT driver * * (c) Copyright 2000-2001 Marek Michalkiewicz * * Based on acquirewdt.c which is based on wdt.c. * Original copyright messages: * * (c) Copyright 1996 Alan Cox , * All Rights Reserved. * * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide * warranty for any of this software. This material is provided * "AS-IS" and at no charge. * * (c) Copyright 1995 Alan Cox * * 14-Dec-2001 Matt Domsch * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT * * 16-Oct-2002 Rob Radez * Clean up ioctls, clean up init + exit, add expect close support, * add wdt_start and wdt_stop as parameters. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #define DRV_NAME "advantechwdt" #define WATCHDOG_NAME "Advantech WDT" #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ /* the watchdog platform device */ static struct platform_device *advwdt_platform_device; static unsigned long advwdt_is_open; static char adv_expect_close; /* * You must set these - there is no sane way to probe for this board. * * To enable or restart, write the timeout value in seconds (1 to 63) * to I/O port wdt_start. To disable, read I/O port wdt_stop. * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but * check your manual (at least the PCA-6159 seems to be different - * the manual says wdt_stop is 0x43, not 0x443). * (0x43 is also a write-only control register for the 8254 timer!) */ static int wdt_stop = 0x443; module_param(wdt_stop, int, 0); MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)"); static int wdt_start = 0x443; module_param(wdt_start, int, 0); MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)"); static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) "."); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); /* * Watchdog Operations */ static void advwdt_ping(void) { /* Write a watchdog value */ outb_p(timeout, wdt_start); } static void advwdt_disable(void) { inb_p(wdt_stop); } static int advwdt_set_heartbeat(int t) { if (t < 1 || t > 63) return -EINVAL; timeout = t; return 0; } /* * /dev/watchdog handling */ static ssize_t advwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { if (count) { if (!nowayout) { size_t i; adv_expect_close = 0; for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') adv_expect_close = 42; } } advwdt_ping(); } return count; } static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int new_timeout; void __user *argp = (void __user *)arg; int __user *p = argp; static const struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = WATCHDOG_NAME, }; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &ident, sizeof(ident))) return -EFAULT; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_SETOPTIONS: { int options, retval = -EINVAL; if (get_user(options, p)) return -EFAULT; if (options & WDIOS_DISABLECARD) { advwdt_disable(); retval = 0; } if (options & WDIOS_ENABLECARD) { advwdt_ping(); retval = 0; } return retval; } case WDIOC_KEEPALIVE: advwdt_ping(); break; case WDIOC_SETTIMEOUT: if (get_user(new_timeout, p)) return -EFAULT; if (advwdt_set_heartbeat(new_timeout)) return -EINVAL; advwdt_ping(); fallthrough; case WDIOC_GETTIMEOUT: return put_user(timeout, p); default: return -ENOTTY; } return 0; } static int advwdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &advwdt_is_open)) return -EBUSY; /* * Activate */ advwdt_ping(); return stream_open(inode, file); } static int advwdt_close(struct inode *inode, struct file *file) { if (adv_expect_close == 42) { advwdt_disable(); } else { pr_crit("Unexpected close, not stopping watchdog!\n"); advwdt_ping(); } clear_bit(0, &advwdt_is_open); adv_expect_close = 0; return 0; } /* * Kernel Interfaces */ static const struct file_operations advwdt_fops = { .owner = THIS_MODULE, .write = advwdt_write, .unlocked_ioctl = advwdt_ioctl, .compat_ioctl = compat_ptr_ioctl, .open = advwdt_open, .release = advwdt_close, }; static struct miscdevice advwdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &advwdt_fops, }; /* * Init & exit routines */ static int __init advwdt_probe(struct platform_device *dev) { int ret; if (wdt_stop != wdt_start) { if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { pr_err("I/O address 0x%04x already in use\n", wdt_stop); ret = -EIO; goto out; } } if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { pr_err("I/O address 0x%04x already in use\n", wdt_start); ret = -EIO; goto unreg_stop; } /* Check that the heartbeat value is within it's range ; * if not reset to the default */ if (advwdt_set_heartbeat(timeout)) { advwdt_set_heartbeat(WATCHDOG_TIMEOUT); pr_info("timeout value must be 1<=x<=63, using %d\n", timeout); } ret = misc_register(&advwdt_miscdev); if (ret != 0) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); goto unreg_regions; } pr_info("initialized. timeout=%d sec (nowayout=%d)\n", timeout, nowayout); out: return ret; unreg_regions: release_region(wdt_start, 1); unreg_stop: if (wdt_stop != wdt_start) release_region(wdt_stop, 1); goto out; } static void advwdt_remove(struct platform_device *dev) { misc_deregister(&advwdt_miscdev); release_region(wdt_start, 1); if (wdt_stop != wdt_start) release_region(wdt_stop, 1); } static void advwdt_shutdown(struct platform_device *dev) { /* Turn the WDT off if we have a soft shutdown */ advwdt_disable(); } static struct platform_driver advwdt_driver = { .remove = advwdt_remove, .shutdown = advwdt_shutdown, .driver = { .name = DRV_NAME, }, }; static int __init advwdt_init(void) { int err; pr_info("WDT driver for Advantech single board computer initialising\n"); advwdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0); if (IS_ERR(advwdt_platform_device)) return PTR_ERR(advwdt_platform_device); err = platform_driver_probe(&advwdt_driver, advwdt_probe); if (err) goto unreg_platform_device; return 0; unreg_platform_device: platform_device_unregister(advwdt_platform_device); return err; } static void __exit advwdt_exit(void) { platform_device_unregister(advwdt_platform_device); platform_driver_unregister(&advwdt_driver); pr_info("Watchdog Module Unloaded\n"); } module_init(advwdt_init); module_exit(advwdt_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Marek Michalkiewicz "); MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");