/* * drivers/char/watchdog/iop_wdt.c * * WDT driver for Intel I/O Processors * Copyright (C) 2005, Intel Corporation. * * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc., 59 Temple * Place - Suite 330, Boston, MA 02111-1307 USA. * * Curt E Bruns <curt.e.bruns@intel.com> * Peter Milne <peter.milne@d-tacq.com> * Dan Williams <dan.j.williams@intel.com> */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/device.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/uaccess.h> #include <mach/hardware.h> static int nowayout = WATCHDOG_NOWAYOUT; static unsigned long wdt_status; static unsigned long boot_status; static spinlock_t wdt_lock; #define WDT_IN_USE 0 #define WDT_OK_TO_CLOSE 1 #define WDT_ENABLED 2 static unsigned long iop_watchdog_timeout(void) { return (0xffffffffUL / get_iop_tick_rate()); } /** * wdt_supports_disable - determine if we are accessing a iop13xx watchdog * or iop3xx by whether it has a disable command */ static int wdt_supports_disable(void) { int can_disable; if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM) can_disable = 1; else can_disable = 0; return can_disable; } static void wdt_enable(void) { /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF * Takes approx. 10.7s to timeout */ spin_lock(&wdt_lock); write_wdtcr(IOP_WDTCR_EN_ARM); write_wdtcr(IOP_WDTCR_EN); spin_unlock(&wdt_lock); } /* returns 0 if the timer was successfully disabled */ static int wdt_disable(void) { /* Stop Counting */ if (wdt_supports_disable()) { spin_lock(&wdt_lock); write_wdtcr(IOP_WDTCR_DIS_ARM); write_wdtcr(IOP_WDTCR_DIS); clear_bit(WDT_ENABLED, &wdt_status); spin_unlock(&wdt_lock); printk(KERN_INFO "WATCHDOG: Disabled\n"); return 0; } else return 1; } static int iop_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(WDT_IN_USE, &wdt_status)) return -EBUSY; clear_bit(WDT_OK_TO_CLOSE, &wdt_status); wdt_enable(); set_bit(WDT_ENABLED, &wdt_status); return nonseekable_open(inode, file); } static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { if (len) { if (!nowayout) { size_t i; clear_bit(WDT_OK_TO_CLOSE, &wdt_status); for (i = 0; i != len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') set_bit(WDT_OK_TO_CLOSE, &wdt_status); } } wdt_enable(); } return len; } static const struct watchdog_info ident = { .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "iop watchdog", }; static long iop_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int options; int ret = -ENOTTY; int __user *argp = (int __user *)arg; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &ident, sizeof(ident))) ret = -EFAULT; else ret = 0; break; case WDIOC_GETSTATUS: ret = put_user(0, argp); break; case WDIOC_GETBOOTSTATUS: ret = put_user(boot_status, argp); break; case WDIOC_SETOPTIONS: if (get_user(options, (int *)arg)) return -EFAULT; if (options & WDIOS_DISABLECARD) { if (!nowayout) { if (wdt_disable() == 0) { set_bit(WDT_OK_TO_CLOSE, &wdt_status); ret = 0; } else ret = -ENXIO; } else ret = 0; } if (options & WDIOS_ENABLECARD) { wdt_enable(); ret = 0; } break; case WDIOC_KEEPALIVE: wdt_enable(); ret = 0; break; case WDIOC_GETTIMEOUT: ret = put_user(iop_watchdog_timeout(), argp); break; } return ret; } static int iop_wdt_release(struct inode *inode, struct file *file) { int state = 1; if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) if (test_bit(WDT_ENABLED, &wdt_status)) state = wdt_disable(); /* if the timer is not disabled reload and notify that we are still * going down */ if (state != 0) { wdt_enable(); printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " "reset in %lu seconds\n", iop_watchdog_timeout()); } clear_bit(WDT_IN_USE, &wdt_status); clear_bit(WDT_OK_TO_CLOSE, &wdt_status); return 0; } static const struct file_operations iop_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = iop_wdt_write, .unlocked_ioctl = iop_wdt_ioctl, .open = iop_wdt_open, .release = iop_wdt_release, }; static struct miscdevice iop_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &iop_wdt_fops, }; static int __init iop_wdt_init(void) { int ret; spin_lock_init(&wdt_lock); /* check if the reset was caused by the watchdog timer */ boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0; /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset * NOTE: An IB Reset will Reset both cores in the IOP342 */ write_wdtsr(IOP13XX_WDTCR_IB_RESET); /* Register after we have the device set up so we cannot race with an open */ ret = misc_register(&iop_wdt_miscdev); if (ret == 0) printk(KERN_INFO "iop watchdog timer: timeout %lu sec\n", iop_watchdog_timeout()); return ret; } static void __exit iop_wdt_exit(void) { misc_deregister(&iop_wdt_miscdev); } module_init(iop_wdt_init); module_exit(iop_wdt_exit); module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>"); MODULE_DESCRIPTION("iop watchdog timer driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);