[PATCH] cirrus ep93xx watchdog driver
Add a driver for the on-chip watchdog on the cirrus ep93xx series of ARM CPUs. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Cc: Wim Van Sebroeck <wim@iguana.be> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Alessandro Zummo
Linus Torvalds
parent
214fda1f6e
commit
f52ac8fec8
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@ -148,6 +148,16 @@ config MPCORE_WATCHDOG
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To compile this driver as a module, choose M here: the
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module will be called mpcore_wdt.
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config EP93XX_WATCHDOG
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tristate "EP93xx Watchdog"
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depends on WATCHDOG && ARCH_EP93XX
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help
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Say Y here if to include support for the watchdog timer
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embedded in the Cirrus Logic EP93xx family of devices.
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To compile this driver as a module, choose M here: the
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module will be called ep93xx_wdt.
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# X86 (i386 + ia64 + x86_64) Architecture
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config ACQUIRE_WDT
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@ -30,6 +30,7 @@ obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o
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obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o
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obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o
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obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o
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obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o
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# X86 (i386 + ia64 + x86_64) Architecture
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obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
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@ -0,0 +1,257 @@
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/*
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* Watchdog driver for Cirrus Logic EP93xx family of devices.
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*
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* Copyright (c) 2004 Ray Lehtiniemi
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* Copyright (c) 2006 Tower Technologies
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* Based on ep93xx driver, bits from alim7101_wdt.c
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*
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* Authors: Ray Lehtiniemi <rayl@mail.com>,
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* Alessandro Zummo <a.zummo@towertech.it>
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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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* This watchdog fires after 250msec, which is a too short interval
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* for us to rely on the user space daemon alone. So we ping the
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* wdt each ~200msec and eventually stop doing it if the user space
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* daemon dies.
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*
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* TODO:
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*
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* - Test last reset from watchdog status
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* - Add a few missing ioctls
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*/
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#include <linux/module.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/timer.h>
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#include <asm/hardware.h>
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#include <asm/uaccess.h>
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#define WDT_VERSION "0.3"
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#define PFX "ep93xx_wdt: "
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/* default timeout (secs) */
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#define WDT_TIMEOUT 30
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static int nowayout = WATCHDOG_NOWAYOUT;
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static int timeout = WDT_TIMEOUT;
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static struct timer_list timer;
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static unsigned long next_heartbeat;
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static unsigned long wdt_status;
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static unsigned long boot_status;
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#define WDT_IN_USE 0
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#define WDT_OK_TO_CLOSE 1
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#define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x))
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#define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00)
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#define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04)
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/* reset the wdt every ~200ms */
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#define WDT_INTERVAL (HZ/5)
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static void wdt_enable(void)
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{
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__raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG);
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}
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static void wdt_disable(void)
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{
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__raw_writew(0xaa55, EP93XX_WDT_WATCHDOG);
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}
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static inline void wdt_ping(void)
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{
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__raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
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}
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static void wdt_startup(void)
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{
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next_heartbeat = jiffies + (timeout * HZ);
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wdt_enable();
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mod_timer(&timer, jiffies + WDT_INTERVAL);
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}
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static void wdt_shutdown(void)
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{
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del_timer_sync(&timer);
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wdt_disable();
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}
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static void wdt_keepalive(void)
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{
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/* user land ping */
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next_heartbeat = jiffies + (timeout * HZ);
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}
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static int ep93xx_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_startup();
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return nonseekable_open(inode, file);
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}
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static ssize_t
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ep93xx_wdt_write(struct file *file, const char __user *data, size_t len,
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loff_t *ppos)
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{
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/* Can't seek (pwrite) on this device */
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if (*ppos != file->f_pos)
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return -ESPIPE;
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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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else
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clear_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 struct watchdog_info ident = {
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.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
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.identity = "EP93xx Watchdog",
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};
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static int
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ep93xx_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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int ret = -ENOIOCTLCMD;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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ret = copy_to_user((struct watchdog_info __user *)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 __user *)arg);
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break;
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case WDIOC_GETBOOTSTATUS:
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ret = put_user(boot_status, (int __user *)arg);
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break;
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case WDIOC_GETTIMEOUT:
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/* actually, it is 0.250 seconds.... */
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ret = put_user(1, (int __user *)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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}
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return ret;
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}
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static int ep93xx_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_shutdown();
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else
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printk(KERN_CRIT PFX "Device closed unexpectedly - "
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"timer will not stop\n");
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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 struct file_operations ep93xx_wdt_fops = {
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.owner = THIS_MODULE,
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.write = ep93xx_wdt_write,
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.ioctl = ep93xx_wdt_ioctl,
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.open = ep93xx_wdt_open,
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.release = ep93xx_wdt_release,
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};
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static struct miscdevice ep93xx_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &ep93xx_wdt_fops,
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};
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static void ep93xx_timer_ping(unsigned long data)
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{
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if (time_before(jiffies, next_heartbeat))
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wdt_ping();
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/* Re-set the timer interval */
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mod_timer(&timer, jiffies + WDT_INTERVAL);
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}
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static int __init ep93xx_wdt_init(void)
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{
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int err;
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err = misc_register(&ep93xx_wdt_miscdev);
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boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
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printk(KERN_INFO PFX "EP93XX watchdog, driver version "
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WDT_VERSION "%s\n",
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(__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
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? " (nCS1 disable detected)" : "");
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if (timeout < 1 || timeout > 3600) {
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timeout = WDT_TIMEOUT;
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printk(KERN_INFO PFX
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"timeout value must be 1<=x<=3600, using %d\n",
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timeout);
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}
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setup_timer(&timer, ep93xx_timer_ping, 1);
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return err;
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}
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static void __exit ep93xx_wdt_exit(void)
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{
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wdt_shutdown();
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misc_deregister(&ep93xx_wdt_miscdev);
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}
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module_init(ep93xx_wdt_init);
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module_exit(ep93xx_wdt_exit);
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
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"Alessandro Zummo <a.zummo@towertech.it>");
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MODULE_DESCRIPTION("EP93xx Watchdog");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(WDT_VERSION);
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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