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/*
* drivers/watchdog/m54xx_wdt.c
*
* Watchdog driver for ColdFire MCF547x & MCF548x processors
* Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be>
*
* Adapted from the IXP4xx watchdog driver, which carries these notices:
*
* Author: Deepak Saxena <dsaxena@plexity.net>
*
* Copyright 2004 (c) MontaVista, Software, Inc.
* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#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/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <asm/coldfire.h>
#include <asm/m54xxsim.h>
#include <asm/m54xxgpt.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */
static unsigned long wdt_status;
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
static void wdt_enable(void)
{
unsigned int gms0;
/* preserve GPIO usage, if any */
gms0 = __raw_readl(MCF_GPT_GMS0);
if (gms0 & MCF_GPT_GMS_TMS_GPIO)
gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK
| MCF_GPT_GMS_OD);
else
gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD;
__raw_writel(gms0, MCF_GPT_GMS0);
__raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) |
MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0);
gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE;
__raw_writel(gms0, MCF_GPT_GMS0);
}
static void wdt_disable(void)
{
unsigned int gms0;
/* disable watchdog */
gms0 = __raw_readl(MCF_GPT_GMS0);
gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE);
__raw_writel(gms0, MCF_GPT_GMS0);
}
static void wdt_keepalive(void)
{
unsigned int gms0;
gms0 = __raw_readl(MCF_GPT_GMS0);
gms0 |= MCF_GPT_GMS_OCPW(0xA5);
__raw_writel(gms0, MCF_GPT_GMS0);
}
static int m54xx_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();
return nonseekable_open(inode, file);
}
static ssize_t m54xx_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_keepalive();
}
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING,
.identity = "Coldfire M54xx Watchdog",
};
static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = -ENOTTY;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_keepalive();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time <= 0 || time > 30) {
ret = -EINVAL;
break;
}
heartbeat = time;
wdt_enable();
/* Fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, (int *)arg);
break;
}
return ret;
}
static int m54xx_wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
wdt_disable();
else {
pr_crit("Device closed unexpectedly - timer will not stop\n");
wdt_keepalive();
}
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations m54xx_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = m54xx_wdt_write,
.unlocked_ioctl = m54xx_wdt_ioctl,
.open = m54xx_wdt_open,
.release = m54xx_wdt_release,
};
static struct miscdevice m54xx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &m54xx_wdt_fops,
};
static int __init m54xx_wdt_init(void)
{
if (!request_mem_region(MCF_GPT_GCIR0, 4, "Coldfire M54xx Watchdog")) {
pr_warn("I/O region busy\n");
return -EBUSY;
}
pr_info("driver is loaded\n");
return misc_register(&m54xx_wdt_miscdev);
}
static void __exit m54xx_wdt_exit(void)
{
misc_deregister(&m54xx_wdt_miscdev);
release_mem_region(MCF_GPT_GCIR0, 4);
}
module_init(m54xx_wdt_init);
module_exit(m54xx_wdt_exit);
MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
MODULE_DESCRIPTION("Coldfire M54xx Watchdog");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_LICENSE("GPL");
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