// SPDX-License-Identifier: GPL-2.0-or-later /* * Intel 21285 watchdog driver * Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998 * * based on * * SoftDog 0.05: A Software Watchdog Device * * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, * All Rights Reserved. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/reboot.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/uaccess.h> #include <linux/irq.h> #include <mach/hardware.h> #include <asm/mach-types.h> #include <asm/system_info.h> #include <asm/hardware/dec21285.h> /* * Define this to stop the watchdog actually rebooting the machine. */ #undef ONLY_TESTING static unsigned int soft_margin = 60; /* in seconds */ static unsigned int reload; static unsigned long timer_alive; #ifdef ONLY_TESTING /* * If the timer expires.. */ static void watchdog_fire(int irq, void *dev_id) { pr_crit("Would Reboot\n"); *CSR_TIMER4_CNTL = 0; *CSR_TIMER4_CLR = 0; } #endif /* * Refresh the timer. */ static void watchdog_ping(void) { *CSR_TIMER4_LOAD = reload; } /* * Allow only one person to hold it open */ static int watchdog_open(struct inode *inode, struct file *file) { int ret; if (*CSR_SA110_CNTL & (1 << 13)) return -EBUSY; if (test_and_set_bit(1, &timer_alive)) return -EBUSY; reload = soft_margin * (mem_fclk_21285 / 256); *CSR_TIMER4_CLR = 0; watchdog_ping(); *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD | TIMER_CNTL_DIV256; #ifdef ONLY_TESTING ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL); if (ret) { *CSR_TIMER4_CNTL = 0; clear_bit(1, &timer_alive); } #else /* * Setting this bit is irreversible; once enabled, there is * no way to disable the watchdog. */ *CSR_SA110_CNTL |= 1 << 13; ret = 0; #endif stream_open(inode, file); return ret; } /* * Shut off the timer. * Note: if we really have enabled the watchdog, there * is no way to turn off. */ static int watchdog_release(struct inode *inode, struct file *file) { #ifdef ONLY_TESTING free_irq(IRQ_TIMER4, NULL); clear_bit(1, &timer_alive); #endif return 0; } static ssize_t watchdog_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { /* * Refresh the timer. */ if (len) watchdog_ping(); return len; } static const struct watchdog_info ident = { .options = WDIOF_SETTIMEOUT, .identity = "Footbridge Watchdog", }; static long watchdog_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int __user *int_arg = (int __user *)arg; int new_margin, ret = -ENOTTY; switch (cmd) { case WDIOC_GETSUPPORT: ret = 0; if (copy_to_user((void __user *)arg, &ident, sizeof(ident))) ret = -EFAULT; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: ret = put_user(0, int_arg); break; case WDIOC_KEEPALIVE: watchdog_ping(); ret = 0; break; case WDIOC_SETTIMEOUT: ret = get_user(new_margin, int_arg); if (ret) break; /* Arbitrary, can't find the card's limits */ if (new_margin < 0 || new_margin > 60) { ret = -EINVAL; break; } soft_margin = new_margin; reload = soft_margin * (mem_fclk_21285 / 256); watchdog_ping(); /* Fall */ case WDIOC_GETTIMEOUT: ret = put_user(soft_margin, int_arg); break; } return ret; } static const struct file_operations watchdog_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = watchdog_write, .unlocked_ioctl = watchdog_ioctl, .open = watchdog_open, .release = watchdog_release, }; static struct miscdevice watchdog_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &watchdog_fops, }; static int __init footbridge_watchdog_init(void) { int retval; if (machine_is_netwinder()) return -ENODEV; retval = misc_register(&watchdog_miscdev); if (retval < 0) return retval; pr_info("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n", soft_margin); if (machine_is_cats()) pr_warn("Warning: Watchdog reset may not work on this machine\n"); return 0; } static void __exit footbridge_watchdog_exit(void) { misc_deregister(&watchdog_miscdev); } MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>"); MODULE_DESCRIPTION("Footbridge watchdog driver"); MODULE_LICENSE("GPL"); module_param(soft_margin, int, 0); MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds"); module_init(footbridge_watchdog_init); module_exit(footbridge_watchdog_exit);