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![Jean Delvare](/assets/img/avatar_default.png)
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements. Either the device is enumerated and the driver already has a module alias (e.g. PCI, USB etc.) that will get the right driver loaded automatically. Or the device is not enumerated and loading its driver will lead to more or less intrusive hardware poking. Such hardware poking should be limited to a bare minimum, so the user should really decide which drivers should be tried and in what order. Trying them all in arbitrary order can't do any good. On top of that, loading that many drivers at once bloats the kernel log. Also many drivers will stay loaded afterward, bloating the output of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets loaded as a dependency) can't even be unloaded! If defining char-major-10-130 is needed then it should happen in user-space. Signed-off-by: Jean Delvare <jdelvare@suse.de> Acked-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Mike Frysinger <vapier.adi@gmail.com> Cc: Wan ZongShun <mcuos.com@gmail.com> Cc: Ben Dooks <ben-linux@fluff.org> Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk> Cc: Jim Cromie <jim.cromie@gmail.com>
225 lines
5 KiB
C
225 lines
5 KiB
C
/*
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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 <phdm@macqel.be>
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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 <dsaxena@plexity.net>
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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 <green@crimea.edu>
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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 <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 nonseekable_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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/* Fall through */
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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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.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 <phdm@macqel.be>");
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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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