[PATCH] cirrus ep93xx watchdog driver (f52ac8fe) · Commits · e / devices / android_kernel_sony_msm8994

drivers/char/watchdog/Kconfig

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Original line number	Diff line number	Diff line
		@@ -148,6 +148,16 @@ config MPCORE_WATCHDOG
		To compile this driver as a module, choose M here: the
		module will be called mpcore_wdt.

		config EP93XX_WATCHDOG
		tristate "EP93xx Watchdog"
		depends on WATCHDOG && ARCH_EP93XX
		help
		Say Y here if to include support for the watchdog timer
		embedded in the Cirrus Logic EP93xx family of devices.

		To compile this driver as a module, choose M here: the
		module will be called ep93xx_wdt.

		# X86 (i386 + ia64 + x86_64) Architecture

		config ACQUIRE_WDT

drivers/char/watchdog/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -30,6 +30,7 @@ obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o
		obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o
		obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o
		obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o
		obj-$(CONFIG_EP93XX_WATCHDOG) += ep93xx_wdt.o

		# X86 (i386 + ia64 + x86_64) Architecture
		obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o

drivers/char/watchdog/ep93xx_wdt.c

0 → 100644

+257 −0

Original line number	Diff line number	Diff line
		/*
		* Watchdog driver for Cirrus Logic EP93xx family of devices.
		*
		* Copyright (c) 2004 Ray Lehtiniemi
		* Copyright (c) 2006 Tower Technologies
		* Based on ep93xx driver, bits from alim7101_wdt.c
		*
		* Authors: Ray Lehtiniemi <rayl@mail.com>,
		* Alessandro Zummo <a.zummo@towertech.it>
		*
		* 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.
		*
		* This watchdog fires after 250msec, which is a too short interval
		* for us to rely on the user space daemon alone. So we ping the
		* wdt each ~200msec and eventually stop doing it if the user space
		* daemon dies.
		*
		* TODO:
		*
		* - Test last reset from watchdog status
		* - Add a few missing ioctls
		*/

		#include <linux/module.h>
		#include <linux/fs.h>
		#include <linux/miscdevice.h>
		#include <linux/watchdog.h>
		#include <linux/timer.h>

		#include <asm/hardware.h>
		#include <asm/uaccess.h>

		#define WDT_VERSION "0.3"
		#define PFX "ep93xx_wdt: "

		/* default timeout (secs) */
		#define WDT_TIMEOUT 30

		static int nowayout = WATCHDOG_NOWAYOUT;
		static int timeout = WDT_TIMEOUT;

		static struct timer_list timer;
		static unsigned long next_heartbeat;
		static unsigned long wdt_status;
		static unsigned long boot_status;

		#define WDT_IN_USE 0
		#define WDT_OK_TO_CLOSE 1

		#define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x))
		#define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00)
		#define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04)

		/* reset the wdt every ~200ms */
		#define WDT_INTERVAL (HZ/5)

		static void wdt_enable(void)
		{
		__raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG);
		}

		static void wdt_disable(void)
		{
		__raw_writew(0xaa55, EP93XX_WDT_WATCHDOG);
		}

		static inline void wdt_ping(void)
		{
		__raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
		}

		static void wdt_startup(void)
		{
		next_heartbeat = jiffies + (timeout * HZ);

		wdt_enable();
		mod_timer(&timer, jiffies + WDT_INTERVAL);
		}

		static void wdt_shutdown(void)
		{
		del_timer_sync(&timer);
		wdt_disable();
		}

		static void wdt_keepalive(void)
		{
		/* user land ping */
		next_heartbeat = jiffies + (timeout * HZ);
		}

		static int ep93xx_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_startup();

		return nonseekable_open(inode, file);
		}

		static ssize_t
		ep93xx_wdt_write(struct file file, const char __user data, size_t len,
		loff_t *ppos)
		{
		/* Can't seek (pwrite) on this device */
		if (*ppos != file->f_pos)
		return -ESPIPE;

		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);
		else
		clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
		}
		}
		wdt_keepalive();
		}

		return len;
		}

		static struct watchdog_info ident = {
		.options = WDIOF_CARDRESET \| WDIOF_MAGICCLOSE,
		.identity = "EP93xx Watchdog",
		};

		static int
		ep93xx_wdt_ioctl(struct inode inode, struct file file, unsigned int cmd,
		unsigned long arg)
		{
		int ret = -ENOIOCTLCMD;

		switch (cmd) {
		case WDIOC_GETSUPPORT:
		ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
		sizeof(ident)) ? -EFAULT : 0;
		break;

		case WDIOC_GETSTATUS:
		ret = put_user(0, (int __user *)arg);
		break;

		case WDIOC_GETBOOTSTATUS:
		ret = put_user(boot_status, (int __user *)arg);
		break;

		case WDIOC_GETTIMEOUT:
		/* actually, it is 0.250 seconds.... */
		ret = put_user(1, (int __user *)arg);
		break;

		case WDIOC_KEEPALIVE:
		wdt_keepalive();
		ret = 0;
		break;
		}
		return ret;
		}

		static int ep93xx_wdt_release(struct inode inode, struct file file)
		{
		if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
		wdt_shutdown();
		else
		printk(KERN_CRIT PFX "Device closed unexpectedly - "
		"timer will not stop\n");

		clear_bit(WDT_IN_USE, &wdt_status);
		clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

		return 0;
		}

		static struct file_operations ep93xx_wdt_fops = {
		.owner = THIS_MODULE,
		.write = ep93xx_wdt_write,
		.ioctl = ep93xx_wdt_ioctl,
		.open = ep93xx_wdt_open,
		.release = ep93xx_wdt_release,
		};

		static struct miscdevice ep93xx_wdt_miscdev = {
		.minor = WATCHDOG_MINOR,
		.name = "watchdog",
		.fops = &ep93xx_wdt_fops,
		};

		static void ep93xx_timer_ping(unsigned long data)
		{
		if (time_before(jiffies, next_heartbeat))
		wdt_ping();

		/* Re-set the timer interval */
		mod_timer(&timer, jiffies + WDT_INTERVAL);
		}

		static int __init ep93xx_wdt_init(void)
		{
		int err;

		err = misc_register(&ep93xx_wdt_miscdev);

		boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;

		printk(KERN_INFO PFX "EP93XX watchdog, driver version "
		WDT_VERSION "%s\n",
		(__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
		? " (nCS1 disable detected)" : "");

		if (timeout < 1 \|\| timeout > 3600) {
		timeout = WDT_TIMEOUT;
		printk(KERN_INFO PFX
		"timeout value must be 1<=x<=3600, using %d\n",
		timeout);
		}

		setup_timer(&timer, ep93xx_timer_ping, 1);
		return err;
		}

		static void __exit ep93xx_wdt_exit(void)
		{
		wdt_shutdown();
		misc_deregister(&ep93xx_wdt_miscdev);
		}

		module_init(ep93xx_wdt_init);
		module_exit(ep93xx_wdt_exit);

		module_param(nowayout, int, 0);
		MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");

		module_param(timeout, int, 0);
		MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");

		MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
		"Alessandro Zummo <a.zummo@towertech.it>");
		MODULE_DESCRIPTION("EP93xx Watchdog");
		MODULE_LICENSE("GPL");
		MODULE_VERSION(WDT_VERSION);
		MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);