[WATCHDOG] ks8695_wdt.c - new KS8695 watchdog driver

Watchdog driver for the Kendin/Micrel KS8695 processor.
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/char/watchdog/Kconfig

@@ -115,6 +115,13 @@ config IXP4XX_WATCHDOG
 
 	  Say N if you are unsure.
 
+config KS8695_WATCHDOG
+	tristate "KS8695 watchdog"
+	depends on ARCH_KS8695
+	help
+	  Watchdog timer embedded into KS8695 processor. This will reboot your
+	  system when the timeout is reached.
+
 config S3C2410_WATCHDOG
 	tristate "S3C2410 Watchdog"
 	depends on ARCH_S3C2410

drivers/char/watchdog/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_21285_WATCHDOG) += wdt285.o
 obj-$(CONFIG_977_WATCHDOG) += wdt977.o
 obj-$(CONFIG_IXP2000_WATCHDOG) += ixp2000_wdt.o
 obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o
+obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o
 obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o
 obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o
 obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o

drivers/char/watchdog/ks8695_wdt.c

+/*
+ * Watchdog driver for Kendin/Micrel KS8695.
+ *
+ * (C) 2007 Andrew Victor
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <asm/bitops.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/arch/regs-timer.h>
+
+
+#define WDT_DEFAULT_TIME	5	/* seconds */
+#define WDT_MAX_TIME		171	/* seconds */
+
+static int wdt_time = WDT_DEFAULT_TIME;
+static int nowayout = WATCHDOG_NOWAYOUT;
+
+module_param(wdt_time, int, 0);
+MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="__MODULE_STRING(WDT_DEFAULT_TIME) ")");
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+#endif
+
+
+static unsigned long ks8695wdt_busy;
+
+/* ......................................................................... */
+
+/*
+ * Disable the watchdog.
+ */
+static void inline ks8695_wdt_stop(void)
+{
+	unsigned long tmcon;
+
+	/* disable timer0 */
+	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
+	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+}
+
+/*
+ * Enable and reset the watchdog.
+ */
+static void inline ks8695_wdt_start(void)
+{
+	unsigned long tmcon;
+	unsigned long tval = wdt_time * CLOCK_TICK_RATE;
+
+	/* disable timer0 */
+	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
+	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+
+	/* program timer0 */
+	__raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
+
+	/* re-enable timer0 */
+	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
+	__raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+}
+
+/*
+ * Reload the watchdog timer.  (ie, pat the watchdog)
+ */
+static void inline ks8695_wdt_reload(void)
+{
+	unsigned long tmcon;
+
+	/* disable, then re-enable timer0 */
+	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
+	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+	__raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+}
+
+/*
+ * Change the watchdog time interval.
+ */
+static int ks8695_wdt_settimeout(int new_time)
+{
+	/*
+	 * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
+	 *
+	 * Since WDV is a 16-bit counter, the maximum period is
+	 * 65536 / 0.256 = 256 seconds.
+	 */
+	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
+		return -EINVAL;
+
+	/* Set new watchdog time. It will be used when ks8695_wdt_start() is called. */
+	wdt_time = new_time;
+	return 0;
+}
+
+/* ......................................................................... */
+
+/*
+ * Watchdog device is opened, and watchdog starts running.
+ */
+static int ks8695_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(0, &ks8695wdt_busy))
+		return -EBUSY;
+
+	ks8695_wdt_start();
+	return nonseekable_open(inode, file);
+}
+
+/*
+ * Close the watchdog device.
+ * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
+ *  disabled.
+ */
+static int ks8695_wdt_close(struct inode *inode, struct file *file)
+{
+	if (!nowayout)
+		ks8695_wdt_stop();	/* Disable the watchdog when file is closed */
+
+	clear_bit(0, &ks8695wdt_busy);
+	return 0;
+}
+
+static struct watchdog_info ks8695_wdt_info = {
+	.identity	= "ks8695 watchdog",
+	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+};
+
+/*
+ * Handle commands from user-space.
+ */
+static int ks8695_wdt_ioctl(struct inode *inode, struct file *file,
+		unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	int new_value;
+
+	switch(cmd) {
+		case WDIOC_KEEPALIVE:
+			ks8695_wdt_reload();	/* pat the watchdog */
+			return 0;
+
+		case WDIOC_GETSUPPORT:
+			return copy_to_user(argp, &ks8695_wdt_info, sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
+
+		case WDIOC_SETTIMEOUT:
+			if (get_user(new_value, p))
+				return -EFAULT;
+
+			if (ks8695_wdt_settimeout(new_value))
+				return -EINVAL;
+
+			/* Enable new time value */
+			ks8695_wdt_start();
+
+			/* Return current value */
+			return put_user(wdt_time, p);
+
+		case WDIOC_GETTIMEOUT:
+			return put_user(wdt_time, p);
+
+		case WDIOC_GETSTATUS:
+		case WDIOC_GETBOOTSTATUS:
+			return put_user(0, p);
+
+		case WDIOC_SETOPTIONS:
+			if (get_user(new_value, p))
+				return -EFAULT;
+
+			if (new_value & WDIOS_DISABLECARD)
+				ks8695_wdt_stop();
+			if (new_value & WDIOS_ENABLECARD)
+				ks8695_wdt_start();
+			return 0;
+
+		default:
+			return -ENOTTY;
+	}
+}
+
+/*
+ * Pat the watchdog whenever device is written to.
+ */
+static ssize_t ks8695_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
+{
+	ks8695_wdt_reload();		/* pat the watchdog */
+	return len;
+}
+
+/* ......................................................................... */
+
+static const struct file_operations ks8695wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.ioctl		= ks8695_wdt_ioctl,
+	.open		= ks8695_wdt_open,
+	.release	= ks8695_wdt_close,
+	.write		= ks8695_wdt_write,
+};
+
+static struct miscdevice ks8695wdt_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &ks8695wdt_fops,
+};
+
+static int __init ks8695wdt_probe(struct platform_device *pdev)
+{
+	int res;
+
+	if (ks8695wdt_miscdev.parent)
+		return -EBUSY;
+	ks8695wdt_miscdev.parent = &pdev->dev;
+
+	res = misc_register(&ks8695wdt_miscdev);
+	if (res)
+		return res;
+
+	printk("KS8695 Watchdog Timer enabled (%d seconds%s)\n", wdt_time, nowayout ? ", nowayout" : "");
+	return 0;
+}
+
+static int __exit ks8695wdt_remove(struct platform_device *pdev)
+{
+	int res;
+
+	res = misc_deregister(&ks8695wdt_miscdev);
+	if (!res)
+		ks8695wdt_miscdev.parent = NULL;
+
+	return res;
+}
+
+static void ks8695wdt_shutdown(struct platform_device *pdev)
+{
+	ks8695_wdt_stop();
+}
+
+#ifdef CONFIG_PM
+
+static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
+{
+	ks8695_wdt_stop();
+	return 0;
+}
+
+static int ks8695wdt_resume(struct platform_device *pdev)
+{
+	if (ks8695wdt_busy)
+		ks8695_wdt_start();
+	return 0;
+}
+
+#else
+#define ks8695wdt_suspend NULL
+#define ks8695wdt_resume	NULL
+#endif
+
+static struct platform_driver ks8695wdt_driver = {
+	.probe		= ks8695wdt_probe,
+	.remove		= __exit_p(ks8695wdt_remove),
+	.shutdown	= ks8695wdt_shutdown,
+	.suspend	= ks8695wdt_suspend,
+	.resume		= ks8695wdt_resume,
+	.driver		= {
+		.name	= "ks8695_wdt",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init ks8695_wdt_init(void)
+{
+	/* Check that the heartbeat value is within range; if not reset to the default */
+	if (ks8695_wdt_settimeout(wdt_time)) {
+		ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
+		pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i, using %d\n", wdt_time, WDT_MAX_TIME);
+	}
+
+	return platform_driver_register(&ks8695wdt_driver);
+}
+
+static void __exit ks8695_wdt_exit(void)
+{
+	platform_driver_unregister(&ks8695wdt_driver);
+}
+
+module_init(ks8695_wdt_init);
+module_exit(ks8695_wdt_exit);
+
+MODULE_AUTHOR("Andrew Victor");
+MODULE_DESCRIPTION("Watchdog driver for KS8695");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);