linux/drivers/watchdog/m54xx_wdt.c
Greg Ungerer 944c3d81db m68knommu: clean up ColdFire 54xx General Timer definitions
Convert the ColdFire 54xx CPU General Timer register address definitions to
include the MCF_MBAR peripheral region offset. This makes them consistent
with all other 54xx address register definitions (in m54xxsim.h).

The goal is to reduce different definitions used (some including offsets and
others not) causing bugs when used incorrectly.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
2012-09-27 23:34:03 +10:00

227 lines
5.0 KiB
C

/*
* 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");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);