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openwrt-xburst/target/linux/ar7/files/drivers/char/watchdog/ar7_wdt.c
nbd afb3c4be87 AR7 watchdog supports magic close
This patch adds the magic close flag (stopping the watchdog on an expected close
by wrting 'V' to the device before closing it) to the watchdogs list, which the
AR7 watchdog code actually supports.

Signed-off-by: Axel Gembe <ago@bastart.eu.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@12666 3c298f89-4303-0410-b956-a3cf2f4a3e73
2008-09-23 15:43:30 +00:00

350 lines
8.2 KiB
C

/*
* drivers/watchdog/ar7_wdt.c
*
* Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
* Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
*
* Some code taken from:
* National Semiconductor SCx200 Watchdog support
* Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <asm/addrspace.h>
#include <asm/ar7/ar7.h>
#define DRVNAME "ar7_wdt"
#define LONGNAME "TI AR7 Watchdog Timer"
MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
MODULE_DESCRIPTION(LONGNAME);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
static int margin = 60;
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
#define READ_REG(x) readl((void __iomem *)&(x))
#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
struct ar7_wdt {
u32 kick_lock;
u32 kick;
u32 change_lock;
u32 change;
u32 disable_lock;
u32 disable;
u32 prescale_lock;
u32 prescale;
};
static struct semaphore open_semaphore;
static unsigned expect_close;
/* XXX currently fixed, allows max margin ~68.72 secs */
#define prescale_value 0xffff
/* Offset of the WDT registers */
static unsigned long ar7_regs_wdt;
/* Pointer to the remapped WDT IO space */
static struct ar7_wdt *ar7_wdt;
static void ar7_wdt_get_regs(void)
{
u16 chip_id = ar7_chip_id();
switch (chip_id) {
case AR7_CHIP_7100:
case AR7_CHIP_7200:
ar7_regs_wdt = AR7_REGS_WDT;
break;
default:
ar7_regs_wdt = UR8_REGS_WDT;
break;
}
}
static void ar7_wdt_kick(u32 value)
{
WRITE_REG(ar7_wdt->kick_lock, 0x5555);
if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
WRITE_REG(ar7_wdt->kick, value);
return;
}
}
printk(KERN_ERR DRVNAME ": failed to unlock WDT kick reg\n");
}
static void ar7_wdt_prescale(u32 value)
{
WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
WRITE_REG(ar7_wdt->prescale, value);
return;
}
}
printk(KERN_ERR DRVNAME ": failed to unlock WDT prescale reg\n");
}
static void ar7_wdt_change(u32 value)
{
WRITE_REG(ar7_wdt->change_lock, 0x6666);
if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
WRITE_REG(ar7_wdt->change, value);
return;
}
}
printk(KERN_ERR DRVNAME ": failed to unlock WDT change reg\n");
}
static void ar7_wdt_disable(u32 value)
{
WRITE_REG(ar7_wdt->disable_lock, 0x7777);
if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
WRITE_REG(ar7_wdt->disable, value);
return;
}
}
}
printk(KERN_ERR DRVNAME ": failed to unlock WDT disable reg\n");
}
static void ar7_wdt_update_margin(int new_margin)
{
u32 change;
change = new_margin * (ar7_vbus_freq() / prescale_value);
if (change < 1) change = 1;
if (change > 0xffff) change = 0xffff;
ar7_wdt_change(change);
margin = change * prescale_value / ar7_vbus_freq();
printk(KERN_INFO DRVNAME
": timer margin %d seconds (prescale %d, change %d, freq %d)\n",
margin, prescale_value, change, ar7_vbus_freq());
}
static void ar7_wdt_enable_wdt(void)
{
printk(KERN_DEBUG DRVNAME ": enabling watchdog timer\n");
ar7_wdt_disable(1);
ar7_wdt_kick(1);
}
static void ar7_wdt_disable_wdt(void)
{
printk(KERN_DEBUG DRVNAME ": disabling watchdog timer\n");
ar7_wdt_disable(0);
}
static int ar7_wdt_open(struct inode *inode, struct file *file)
{
/* only allow one at a time */
if (down_trylock(&open_semaphore))
return -EBUSY;
ar7_wdt_enable_wdt();
expect_close = 0;
return nonseekable_open(inode, file);
}
static int ar7_wdt_release(struct inode *inode, struct file *file)
{
if (!expect_close)
printk(KERN_WARNING DRVNAME
": watchdog device closed unexpectedly,"
"will not disable the watchdog timer\n");
else if (!nowayout)
ar7_wdt_disable_wdt();
up(&open_semaphore);
return 0;
}
static int ar7_wdt_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_HALT || code == SYS_POWER_OFF)
if (!nowayout)
ar7_wdt_disable_wdt();
return NOTIFY_DONE;
}
static struct notifier_block ar7_wdt_notifier = {
.notifier_call = ar7_wdt_notify_sys
};
static ssize_t ar7_wdt_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
/* check for a magic close character */
if (len) {
size_t i;
ar7_wdt_kick(1);
expect_close = 0;
for (i = 0; i < len; ++i) {
char c;
if (get_user(c, data+i))
return -EFAULT;
if (c == 'V')
expect_close = 1;
}
}
return len;
}
static int ar7_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
static struct watchdog_info ident = {
.identity = LONGNAME,
.firmware_version = 1,
.options = (WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING),
};
int new_margin;
switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT:
if (copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
if (put_user(0, (int *)arg))
return -EFAULT;
return 0;
case WDIOC_KEEPALIVE:
ar7_wdt_kick(1);
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, (int *)arg))
return -EFAULT;
if (new_margin < 1)
return -EINVAL;
ar7_wdt_update_margin(new_margin);
ar7_wdt_kick(1);
case WDIOC_GETTIMEOUT:
if (put_user(margin, (int *)arg))
return -EFAULT;
return 0;
}
}
static struct file_operations ar7_wdt_fops = {
.owner = THIS_MODULE,
.write = ar7_wdt_write,
.ioctl = ar7_wdt_ioctl,
.open = ar7_wdt_open,
.release = ar7_wdt_release,
};
static struct miscdevice ar7_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ar7_wdt_fops,
};
static int __init ar7_wdt_init(void)
{
int rc;
ar7_wdt_get_regs();
if (!request_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt),
LONGNAME)) {
printk(KERN_WARNING DRVNAME ": watchdog I/O region busy\n");
return -EBUSY;
}
ar7_wdt = (struct ar7_wdt *)
ioremap(ar7_regs_wdt, sizeof(struct ar7_wdt));
ar7_wdt_disable_wdt();
ar7_wdt_prescale(prescale_value);
ar7_wdt_update_margin(margin);
sema_init(&open_semaphore, 1);
rc = register_reboot_notifier(&ar7_wdt_notifier);
if (rc) {
printk(KERN_ERR DRVNAME
": unable to register reboot notifier\n");
goto out_alloc;
}
rc = misc_register(&ar7_wdt_miscdev);
if (rc) {
printk(KERN_ERR DRVNAME ": unable to register misc device\n");
goto out_register;
}
goto out;
out_register:
unregister_reboot_notifier(&ar7_wdt_notifier);
out_alloc:
iounmap(ar7_wdt);
release_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt));
out:
return rc;
}
static void __exit ar7_wdt_cleanup(void)
{
misc_deregister(&ar7_wdt_miscdev);
unregister_reboot_notifier(&ar7_wdt_notifier);
iounmap(ar7_wdt);
release_mem_region(ar7_regs_wdt, sizeof(struct ar7_wdt));
}
module_init(ar7_wdt_init);
module_exit(ar7_wdt_cleanup);