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227 lines
5.1 KiB
227 lines
5.1 KiB
/* |
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* drivers/watchdog/m54xx_wdt.c |
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* |
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* Watchdog driver for ColdFire MCF547x & MCF548x processors |
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* Copyright 2010 (c) Philippe De Muyter <[email protected]> |
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* |
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* Adapted from the IXP4xx watchdog driver, which carries these notices: |
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* |
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* Author: Deepak Saxena <[email protected]> |
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* |
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* Copyright 2004 (c) MontaVista, Software, Inc. |
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* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <[email protected]> |
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* |
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* This file is licensed under the terms of the GNU General Public |
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* License version 2. This program is licensed "as is" without any |
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* warranty of any kind, whether express or implied. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/fs.h> |
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#include <linux/miscdevice.h> |
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#include <linux/watchdog.h> |
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#include <linux/init.h> |
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#include <linux/bitops.h> |
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#include <linux/ioport.h> |
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#include <linux/uaccess.h> |
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#include <linux/io.h> |
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#include <asm/coldfire.h> |
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#include <asm/m54xxsim.h> |
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#include <asm/m54xxgpt.h> |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */ |
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static unsigned long wdt_status; |
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#define WDT_IN_USE 0 |
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#define WDT_OK_TO_CLOSE 1 |
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static void wdt_enable(void) |
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{ |
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unsigned int gms0; |
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/* preserve GPIO usage, if any */ |
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gms0 = __raw_readl(MCF_GPT_GMS0); |
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if (gms0 & MCF_GPT_GMS_TMS_GPIO) |
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gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK |
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| MCF_GPT_GMS_OD); |
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else |
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gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD; |
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__raw_writel(gms0, MCF_GPT_GMS0); |
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__raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) | |
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MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0); |
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gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE; |
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__raw_writel(gms0, MCF_GPT_GMS0); |
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} |
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static void wdt_disable(void) |
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{ |
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unsigned int gms0; |
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/* disable watchdog */ |
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gms0 = __raw_readl(MCF_GPT_GMS0); |
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gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE); |
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__raw_writel(gms0, MCF_GPT_GMS0); |
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} |
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static void wdt_keepalive(void) |
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{ |
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unsigned int gms0; |
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gms0 = __raw_readl(MCF_GPT_GMS0); |
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gms0 |= MCF_GPT_GMS_OCPW(0xA5); |
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__raw_writel(gms0, MCF_GPT_GMS0); |
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} |
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static int m54xx_wdt_open(struct inode *inode, struct file *file) |
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{ |
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if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
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return -EBUSY; |
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
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wdt_enable(); |
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return stream_open(inode, file); |
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} |
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static ssize_t m54xx_wdt_write(struct file *file, const char *data, |
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size_t len, loff_t *ppos) |
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{ |
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if (len) { |
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if (!nowayout) { |
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size_t i; |
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
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for (i = 0; i != len; i++) { |
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char c; |
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if (get_user(c, data + i)) |
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return -EFAULT; |
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if (c == 'V') |
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set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
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} |
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} |
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wdt_keepalive(); |
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} |
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return len; |
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} |
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static const struct watchdog_info ident = { |
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.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
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WDIOF_KEEPALIVEPING, |
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.identity = "Coldfire M54xx Watchdog", |
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}; |
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static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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int ret = -ENOTTY; |
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int time; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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ret = copy_to_user((struct watchdog_info *)arg, &ident, |
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sizeof(ident)) ? -EFAULT : 0; |
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break; |
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case WDIOC_GETSTATUS: |
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ret = put_user(0, (int *)arg); |
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break; |
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case WDIOC_GETBOOTSTATUS: |
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ret = put_user(0, (int *)arg); |
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break; |
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case WDIOC_KEEPALIVE: |
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wdt_keepalive(); |
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ret = 0; |
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break; |
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case WDIOC_SETTIMEOUT: |
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ret = get_user(time, (int *)arg); |
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if (ret) |
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break; |
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if (time <= 0 || time > 30) { |
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ret = -EINVAL; |
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break; |
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} |
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heartbeat = time; |
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wdt_enable(); |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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ret = put_user(heartbeat, (int *)arg); |
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break; |
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} |
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return ret; |
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} |
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static int m54xx_wdt_release(struct inode *inode, struct file *file) |
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{ |
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if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) |
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wdt_disable(); |
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else { |
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pr_crit("Device closed unexpectedly - timer will not stop\n"); |
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wdt_keepalive(); |
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} |
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clear_bit(WDT_IN_USE, &wdt_status); |
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
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return 0; |
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} |
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static const struct file_operations m54xx_wdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = m54xx_wdt_write, |
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.unlocked_ioctl = m54xx_wdt_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = m54xx_wdt_open, |
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.release = m54xx_wdt_release, |
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}; |
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static struct miscdevice m54xx_wdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &m54xx_wdt_fops, |
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}; |
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static int __init m54xx_wdt_init(void) |
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{ |
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if (!request_mem_region(MCF_GPT_GCIR0, 4, "Coldfire M54xx Watchdog")) { |
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pr_warn("I/O region busy\n"); |
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return -EBUSY; |
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} |
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pr_info("driver is loaded\n"); |
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return misc_register(&m54xx_wdt_miscdev); |
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} |
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static void __exit m54xx_wdt_exit(void) |
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{ |
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misc_deregister(&m54xx_wdt_miscdev); |
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release_mem_region(MCF_GPT_GCIR0, 4); |
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} |
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module_init(m54xx_wdt_init); |
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module_exit(m54xx_wdt_exit); |
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MODULE_AUTHOR("Philippe De Muyter <[email protected]>"); |
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MODULE_DESCRIPTION("Coldfire M54xx Watchdog"); |
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module_param(heartbeat, int, 0); |
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MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)"); |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
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MODULE_LICENSE("GPL");
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