/* * SBC8360 Watchdog driver * * (c) Copyright 2005 Webcon, Inc. * * Based on ib700wdt.c, which is based on advantechwdt.c which is based * on acquirewdt.c which is based on wdt.c. * * (c) Copyright 2001 Charles Howes * * Based on advantechwdt.c which is based on acquirewdt.c which * is based on wdt.c. * * (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. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * 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 * Added timeout module option to override default * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include static unsigned long sbc8360_is_open; static char expect_close; /* * * Watchdog Timer Configuration * * The function of the watchdog timer is to reset the system automatically * and is defined at I/O port 0120H and 0121H. To enable the watchdog timer * and allow the system to reset, write appropriate values from the table * below to I/O port 0120H and 0121H. To disable the timer, write a zero * value to I/O port 0121H for the system to stop the watchdog function. * * The following describes how the timer should be programmed (according to * the vendor documentation) * * Enabling Watchdog: * MOV AX,000AH (enable, phase I) * MOV DX,0120H * OUT DX,AX * MOV AX,000BH (enable, phase II) * MOV DX,0120H * OUT DX,AX * MOV AX,000nH (set multiplier n, from 1-4) * MOV DX,0120H * OUT DX,AX * MOV AX,000mH (set base timer m, from 0-F) * MOV DX,0121H * OUT DX,AX * * Reset timer: * MOV AX,000mH (same as set base timer, above) * MOV DX,0121H * OUT DX,AX * * Disabling Watchdog: * MOV AX,0000H (a zero value) * MOV DX,0120H * OUT DX,AX * * Watchdog timeout configuration values: * N * M | 1 2 3 4 * --|---------------------------------- * 0 | 0.5s 5s 50s 100s * 1 | 1s 10s 100s 200s * 2 | 1.5s 15s 150s 300s * 3 | 2s 20s 200s 400s * 4 | 2.5s 25s 250s 500s * 5 | 3s 30s 300s 600s * 6 | 3.5s 35s 350s 700s * 7 | 4s 40s 400s 800s * 8 | 4.5s 45s 450s 900s * 9 | 5s 50s 500s 1000s * A | 5.5s 55s 550s 1100s * B | 6s 60s 600s 1200s * C | 6.5s 65s 650s 1300s * D | 7s 70s 700s 1400s * E | 7.5s 75s 750s 1500s * F | 8s 80s 800s 1600s * * Another way to say the same things is: * For N=1, Timeout = (M+1) * 0.5s * For N=2, Timeout = (M+1) * 5s * For N=3, Timeout = (M+1) * 50s * For N=4, Timeout = (M+1) * 100s * */ static int wd_times[64][2] = { {0, 1}, /* 0 = 0.5s */ {1, 1}, /* 1 = 1s */ {2, 1}, /* 2 = 1.5s */ {3, 1}, /* 3 = 2s */ {4, 1}, /* 4 = 2.5s */ {5, 1}, /* 5 = 3s */ {6, 1}, /* 6 = 3.5s */ {7, 1}, /* 7 = 4s */ {8, 1}, /* 8 = 4.5s */ {9, 1}, /* 9 = 5s */ {0xA, 1}, /* 10 = 5.5s */ {0xB, 1}, /* 11 = 6s */ {0xC, 1}, /* 12 = 6.5s */ {0xD, 1}, /* 13 = 7s */ {0xE, 1}, /* 14 = 7.5s */ {0xF, 1}, /* 15 = 8s */ {0, 2}, /* 16 = 5s */ {1, 2}, /* 17 = 10s */ {2, 2}, /* 18 = 15s */ {3, 2}, /* 19 = 20s */ {4, 2}, /* 20 = 25s */ {5, 2}, /* 21 = 30s */ {6, 2}, /* 22 = 35s */ {7, 2}, /* 23 = 40s */ {8, 2}, /* 24 = 45s */ {9, 2}, /* 25 = 50s */ {0xA, 2}, /* 26 = 55s */ {0xB, 2}, /* 27 = 60s */ {0xC, 2}, /* 28 = 65s */ {0xD, 2}, /* 29 = 70s */ {0xE, 2}, /* 30 = 75s */ {0xF, 2}, /* 31 = 80s */ {0, 3}, /* 32 = 50s */ {1, 3}, /* 33 = 100s */ {2, 3}, /* 34 = 150s */ {3, 3}, /* 35 = 200s */ {4, 3}, /* 36 = 250s */ {5, 3}, /* 37 = 300s */ {6, 3}, /* 38 = 350s */ {7, 3}, /* 39 = 400s */ {8, 3}, /* 40 = 450s */ {9, 3}, /* 41 = 500s */ {0xA, 3}, /* 42 = 550s */ {0xB, 3}, /* 43 = 600s */ {0xC, 3}, /* 44 = 650s */ {0xD, 3}, /* 45 = 700s */ {0xE, 3}, /* 46 = 750s */ {0xF, 3}, /* 47 = 800s */ {0, 4}, /* 48 = 100s */ {1, 4}, /* 49 = 200s */ {2, 4}, /* 50 = 300s */ {3, 4}, /* 51 = 400s */ {4, 4}, /* 52 = 500s */ {5, 4}, /* 53 = 600s */ {6, 4}, /* 54 = 700s */ {7, 4}, /* 55 = 800s */ {8, 4}, /* 56 = 900s */ {9, 4}, /* 57 = 1000s */ {0xA, 4}, /* 58 = 1100s */ {0xB, 4}, /* 59 = 1200s */ {0xC, 4}, /* 60 = 1300s */ {0xD, 4}, /* 61 = 1400s */ {0xE, 4}, /* 62 = 1500s */ {0xF, 4} /* 63 = 1600s */ }; #define SBC8360_ENABLE 0x120 #define SBC8360_BASETIME 0x121 static int timeout = 27; static int wd_margin = 0xB; static int wd_multiplier = 2; static bool nowayout = WATCHDOG_NOWAYOUT; module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))"); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); /* * Kernel methods. */ /* Activate and pre-configure watchdog */ static void sbc8360_activate(void) { /* Enable the watchdog */ outb(0x0A, SBC8360_ENABLE); msleep_interruptible(100); outb(0x0B, SBC8360_ENABLE); msleep_interruptible(100); /* Set timeout multiplier */ outb(wd_multiplier, SBC8360_ENABLE); msleep_interruptible(100); /* Nothing happens until first sbc8360_ping() */ } /* Kernel pings watchdog */ static void sbc8360_ping(void) { /* Write the base timer register */ outb(wd_margin, SBC8360_BASETIME); } /* stop watchdog */ static void sbc8360_stop(void) { /* De-activate the watchdog */ outb(0, SBC8360_ENABLE); } /* Userspace pings kernel driver, or requests clean close */ static ssize_t sbc8360_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { if (count) { if (!nowayout) { size_t i; /* In case it was set long ago */ expect_close = 0; for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } sbc8360_ping(); } return count; } static int sbc8360_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &sbc8360_is_open)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); /* Activate and ping once to start the countdown */ sbc8360_activate(); sbc8360_ping(); return nonseekable_open(inode, file); } static int sbc8360_close(struct inode *inode, struct file *file) { if (expect_close == 42) sbc8360_stop(); else pr_crit("SBC8360 device closed unexpectedly. SBC8360 will not stop!\n"); clear_bit(0, &sbc8360_is_open); expect_close = 0; return 0; } /* * Notifier for system down */ static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) sbc8360_stop(); /* Disable the SBC8360 Watchdog */ return NOTIFY_DONE; } /* * Kernel Interfaces */ static const struct file_operations sbc8360_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = sbc8360_write, .open = sbc8360_open, .release = sbc8360_close, }; static struct miscdevice sbc8360_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &sbc8360_fops, }; /* * The SBC8360 needs to learn about soft shutdowns in order to * turn the timebomb registers off. */ static struct notifier_block sbc8360_notifier = { .notifier_call = sbc8360_notify_sys, }; static int __init sbc8360_init(void) { int res; unsigned long int mseconds = 60000; if (timeout < 0 || timeout > 63) { pr_err("Invalid timeout index (must be 0-63)\n"); res = -EINVAL; goto out; } if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) { pr_err("ENABLE method I/O %X is not available\n", SBC8360_ENABLE); res = -EIO; goto out; } if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) { pr_err("BASETIME method I/O %X is not available\n", SBC8360_BASETIME); res = -EIO; goto out_nobasetimereg; } res = register_reboot_notifier(&sbc8360_notifier); if (res) { pr_err("Failed to register reboot notifier\n"); goto out_noreboot; } res = misc_register(&sbc8360_miscdev); if (res) { pr_err("failed to register misc device\n"); goto out_nomisc; } wd_margin = wd_times[timeout][0]; wd_multiplier = wd_times[timeout][1]; if (wd_multiplier == 1) mseconds = (wd_margin + 1) * 500; else if (wd_multiplier == 2) mseconds = (wd_margin + 1) * 5000; else if (wd_multiplier == 3) mseconds = (wd_margin + 1) * 50000; else if (wd_multiplier == 4) mseconds = (wd_margin + 1) * 100000; /* My kingdom for the ability to print "0.5 seconds" in the kernel! */ pr_info("Timeout set at %ld ms\n", mseconds); return 0; out_nomisc: unregister_reboot_notifier(&sbc8360_notifier); out_noreboot: release_region(SBC8360_BASETIME, 1); out_nobasetimereg: release_region(SBC8360_ENABLE, 1); out: return res; } static void __exit sbc8360_exit(void) { misc_deregister(&sbc8360_miscdev); unregister_reboot_notifier(&sbc8360_notifier); release_region(SBC8360_ENABLE, 1); release_region(SBC8360_BASETIME, 1); } module_init(sbc8360_init); module_exit(sbc8360_exit); MODULE_AUTHOR("Ian E. Morgan "); MODULE_DESCRIPTION("SBC8360 watchdog driver"); MODULE_LICENSE("GPL"); MODULE_VERSION("1.01"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); /* end of sbc8360.c */