s390/watchdog: use watchdog API

Converted the vmwatchdog driver to use the kernel's watchdog API.

Signed-off-by: Philipp Hachtmann <phacht@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

8 files changed, 294 insertions, 341 deletions

diff --git a/arch/s390/configs/default_defconfig b/arch/s390/configs/default_defconfig
index 8df022c..350ea0d 100644
--- a/arch/s390/configs/default_defconfig
+++ b/arch/s390/configs/default_defconfig
@@ -456,6 +456,7 @@ CONFIG_TN3270_FS=y
 CONFIG_WATCHDOG=y
 CONFIG_WATCHDOG_NOWAYOUT=y
 CONFIG_SOFT_WATCHDOG=m
+CONFIG_DIAG288_WATCHDOG=m
 # CONFIG_HID is not set
 # CONFIG_USB_SUPPORT is not set
 CONFIG_INFINIBAND=m
diff --git a/arch/s390/configs/gcov_defconfig b/arch/s390/configs/gcov_defconfig
index c81a74e..6870648 100644
--- a/arch/s390/configs/gcov_defconfig
+++ b/arch/s390/configs/gcov_defconfig
@@ -453,6 +453,7 @@ CONFIG_TN3270_FS=y
 CONFIG_WATCHDOG=y
 CONFIG_WATCHDOG_NOWAYOUT=y
 CONFIG_SOFT_WATCHDOG=m
+CONFIG_DIAG288_WATCHDOG=m
 # CONFIG_HID is not set
 # CONFIG_USB_SUPPORT is not set
 CONFIG_INFINIBAND=m
diff --git a/arch/s390/configs/performance_defconfig b/arch/s390/configs/performance_defconfig
index b5ba8fe..54ebb85 100644
--- a/arch/s390/configs/performance_defconfig
+++ b/arch/s390/configs/performance_defconfig
@@ -451,6 +451,7 @@ CONFIG_TN3270_FS=y
 CONFIG_WATCHDOG=y
 CONFIG_WATCHDOG_NOWAYOUT=y
 CONFIG_SOFT_WATCHDOG=m
+CONFIG_DIAG288_WATCHDOG=m
 # CONFIG_HID is not set
 # CONFIG_USB_SUPPORT is not set
 CONFIG_INFINIBAND=m
diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
index 629fcc2..78b6ace 100644
--- a/drivers/s390/char/Makefile
+++ b/drivers/s390/char/Makefile
@@ -19,7 +19,6 @@ obj-$(CONFIG_SCLP_VT220_TTY) += sclp_vt220.o
 obj-$(CONFIG_SCLP_CPI) += sclp_cpi.o
 obj-$(CONFIG_SCLP_ASYNC) += sclp_async.o
 
-obj-$(CONFIG_ZVM_WATCHDOG) += vmwatchdog.o
 obj-$(CONFIG_VMLOGRDR) += vmlogrdr.o
 obj-$(CONFIG_VMCP) += vmcp.o
 
diff --git a/drivers/s390/char/vmwatchdog.c b/drivers/s390/char/vmwatchdog.c
deleted file mode 100644
index d5eac98..0000000
--- a/drivers/s390/char/vmwatchdog.c
+++ /dev/null
@@ -1,338 +0,0 @@
-/*
- * Watchdog implementation based on z/VM Watchdog Timer API
- *
- * Copyright IBM Corp. 2004, 2009
- *
- * The user space watchdog daemon can use this driver as
- * /dev/vmwatchdog to have z/VM execute the specified CP
- * command when the timeout expires. The default command is
- * "IPL", which which cause an immediate reboot.
- */
-#define KMSG_COMPONENT "vmwatchdog"
-#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
-
-#include <linux/init.h>
-#include <linux/fs.h>
-#include <linux/kernel.h>
-#include <linux/miscdevice.h>
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/slab.h>
-#include <linux/suspend.h>
-#include <linux/watchdog.h>
-
-#include <asm/ebcdic.h>
-#include <asm/io.h>
-#include <asm/uaccess.h>
-
-#define MAX_CMDLEN 240
-#define MIN_INTERVAL 15
-static char vmwdt_cmd[MAX_CMDLEN] = "IPL";
-static bool vmwdt_conceal;
-
-static bool vmwdt_nowayout = WATCHDOG_NOWAYOUT;
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
-MODULE_DESCRIPTION("z/VM Watchdog Timer");
-module_param_string(cmd, vmwdt_cmd, MAX_CMDLEN, 0644);
-MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers");
-module_param_named(conceal, vmwdt_conceal, bool, 0644);
-MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog "
-		" is active");
-module_param_named(nowayout, vmwdt_nowayout, bool, 0);
-MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
-		" (default=CONFIG_WATCHDOG_NOWAYOUT)");
-MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
-
-static unsigned int vmwdt_interval = 60;
-static unsigned long vmwdt_is_open;
-static int vmwdt_expect_close;
-
-static DEFINE_MUTEX(vmwdt_mutex);
-
-#define VMWDT_OPEN	0	/* devnode is open or suspend in progress */
-#define VMWDT_RUNNING	1	/* The watchdog is armed */
-
-enum vmwdt_func {
-	/* function codes */
-	wdt_init   = 0,
-	wdt_change = 1,
-	wdt_cancel = 2,
-	/* flags */
-	wdt_conceal = 0x80000000,
-};
-
-static int __diag288(enum vmwdt_func func, unsigned int timeout,
-			    char *cmd, size_t len)
-{
-	register unsigned long __func asm("2") = func;
-	register unsigned long __timeout asm("3") = timeout;
-	register unsigned long __cmdp asm("4") = virt_to_phys(cmd);
-	register unsigned long __cmdl asm("5") = len;
-	int err;
-
-	err = -EINVAL;
-	asm volatile(
-		"	diag	%1,%3,0x288\n"
-		"0:	la	%0,0\n"
-		"1:\n"
-		EX_TABLE(0b,1b)
-		: "+d" (err) : "d"(__func), "d"(__timeout),
-		  "d"(__cmdp), "d"(__cmdl) : "1", "cc");
-	return err;
-}
-
-static int vmwdt_keepalive(void)
-{
-	/* we allocate new memory every time to avoid having
-	 * to track the state. static allocation is not an
-	 * option since that might not be contiguous in real
-	 * storage in case of a modular build */
-	static char *ebc_cmd;
-	size_t len;
-	int ret;
-	unsigned int func;
-
-	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
-	if (!ebc_cmd)
-		return -ENOMEM;
-
-	len = strlcpy(ebc_cmd, vmwdt_cmd, MAX_CMDLEN);
-	ASCEBC(ebc_cmd, MAX_CMDLEN);
-	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
-
-	func = vmwdt_conceal ? (wdt_init | wdt_conceal) : wdt_init;
-	set_bit(VMWDT_RUNNING, &vmwdt_is_open);
-	ret = __diag288(func, vmwdt_interval, ebc_cmd, len);
-	WARN_ON(ret != 0);
-	kfree(ebc_cmd);
-	return ret;
-}
-
-static int vmwdt_disable(void)
-{
-	char cmd[] = {'\0'};
-	int ret = __diag288(wdt_cancel, 0, cmd, 0);
-	WARN_ON(ret != 0);
-	clear_bit(VMWDT_RUNNING, &vmwdt_is_open);
-	return ret;
-}
-
-static int __init vmwdt_probe(void)
-{
-	/* there is no real way to see if the watchdog is supported,
-	 * so we try initializing it with a NOP command ("BEGIN")
-	 * that won't cause any harm even if the following disable
-	 * fails for some reason */
-	char ebc_begin[] = {
-		194, 197, 199, 201, 213
-	};
-	if (__diag288(wdt_init, 15, ebc_begin, sizeof(ebc_begin)) != 0)
-		return -EINVAL;
-	return vmwdt_disable();
-}
-
-static int vmwdt_open(struct inode *i, struct file *f)
-{
-	int ret;
-	if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open))
-		return -EBUSY;
-	ret = vmwdt_keepalive();
-	if (ret)
-		clear_bit(VMWDT_OPEN, &vmwdt_is_open);
-	return ret ? ret : nonseekable_open(i, f);
-}
-
-static int vmwdt_close(struct inode *i, struct file *f)
-{
-	if (vmwdt_expect_close == 42)
-		vmwdt_disable();
-	vmwdt_expect_close = 0;
-	clear_bit(VMWDT_OPEN, &vmwdt_is_open);
-	return 0;
-}
-
-static struct watchdog_info vmwdt_info = {
-	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
-	.firmware_version = 0,
-	.identity = "z/VM Watchdog Timer",
-};
-
-static int __vmwdt_ioctl(unsigned int cmd, unsigned long arg)
-{
-	switch (cmd) {
-	case WDIOC_GETSUPPORT:
-		if (copy_to_user((void __user *)arg, &vmwdt_info,
-					sizeof(vmwdt_info)))
-			return -EFAULT;
-		return 0;
-	case WDIOC_GETSTATUS:
-	case WDIOC_GETBOOTSTATUS:
-		return put_user(0, (int __user *)arg);
-	case WDIOC_GETTEMP:
-		return -EINVAL;
-	case WDIOC_SETOPTIONS:
-		{
-			int options, ret;
-			if (get_user(options, (int __user *)arg))
-				return -EFAULT;
-			ret = -EINVAL;
-			if (options & WDIOS_DISABLECARD) {
-				ret = vmwdt_disable();
-				if (ret)
-					return ret;
-			}
-			if (options & WDIOS_ENABLECARD) {
-				ret = vmwdt_keepalive();
-			}
-			return ret;
-		}
-	case WDIOC_GETTIMEOUT:
-		return put_user(vmwdt_interval, (int __user *)arg);
-	case WDIOC_SETTIMEOUT:
-		{
-			int interval;
-			if (get_user(interval, (int __user *)arg))
-				return -EFAULT;
-			if (interval < MIN_INTERVAL)
-				return -EINVAL;
-			vmwdt_interval = interval;
-		}
-		return vmwdt_keepalive();
-	case WDIOC_KEEPALIVE:
-		return vmwdt_keepalive();
-	}
-	return -EINVAL;
-}
-
-static long vmwdt_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
-{
-	int rc;
-
-	mutex_lock(&vmwdt_mutex);
-	rc = __vmwdt_ioctl(cmd, arg);
-	mutex_unlock(&vmwdt_mutex);
-	return (long) rc;
-}
-
-static ssize_t vmwdt_write(struct file *f, const char __user *buf,
-				size_t count, loff_t *ppos)
-{
-	if(count) {
-		if (!vmwdt_nowayout) {
-			size_t i;
-
-			/* note: just in case someone wrote the magic character
-			 * five months ago... */
-			vmwdt_expect_close = 0;
-
-			for (i = 0; i != count; i++) {
-				char c;
-				if (get_user(c, buf+i))
-					return -EFAULT;
-				if (c == 'V')
-					vmwdt_expect_close = 42;
-			}
-		}
-		/* someone wrote to us, we should restart timer */
-		vmwdt_keepalive();
-	}
-	return count;
-}
-
-static int vmwdt_resume(void)
-{
-	clear_bit(VMWDT_OPEN, &vmwdt_is_open);
-	return NOTIFY_DONE;
-}
-
-/*
- * It makes no sense to go into suspend while the watchdog is running.
- * Depending on the memory size, the watchdog might trigger, while we
- * are still saving the memory.
- * We reuse the open flag to ensure that suspend and watchdog open are
- * exclusive operations
- */
-static int vmwdt_suspend(void)
-{
-	if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open)) {
-		pr_err("The system cannot be suspended while the watchdog"
-			" is in use\n");
-		return notifier_from_errno(-EBUSY);
-	}
-	if (test_bit(VMWDT_RUNNING, &vmwdt_is_open)) {
-		clear_bit(VMWDT_OPEN, &vmwdt_is_open);
-		pr_err("The system cannot be suspended while the watchdog"
-			" is running\n");
-		return notifier_from_errno(-EBUSY);
-	}
-	return NOTIFY_DONE;
-}
-
-/*
- * This function is called for suspend and resume.
- */
-static int vmwdt_power_event(struct notifier_block *this, unsigned long event,
-			     void *ptr)
-{
-	switch (event) {
-	case PM_POST_HIBERNATION:
-	case PM_POST_SUSPEND:
-		return vmwdt_resume();
-	case PM_HIBERNATION_PREPARE:
-	case PM_SUSPEND_PREPARE:
-		return vmwdt_suspend();
-	default:
-		return NOTIFY_DONE;
-	}
-}
-
-static struct notifier_block vmwdt_power_notifier = {
-	.notifier_call = vmwdt_power_event,
-};
-
-static const struct file_operations vmwdt_fops = {
-	.open    = &vmwdt_open,
-	.release = &vmwdt_close,
-	.unlocked_ioctl = &vmwdt_ioctl,
-	.write   = &vmwdt_write,
-	.owner   = THIS_MODULE,
-	.llseek  = noop_llseek,
-};
-
-static struct miscdevice vmwdt_dev = {
-	.minor      = WATCHDOG_MINOR,
-	.name       = "watchdog",
-	.fops       = &vmwdt_fops,
-};
-
-static int __init vmwdt_init(void)
-{
-	int ret;
-
-	ret = vmwdt_probe();
-	if (ret)
-		return ret;
-	ret = register_pm_notifier(&vmwdt_power_notifier);
-	if (ret)
-		return ret;
-	/*
-	 * misc_register() has to be the last action in module_init(), because
-	 * file operations will be available right after this.
-	 */
-	ret = misc_register(&vmwdt_dev);
-	if (ret) {
-		unregister_pm_notifier(&vmwdt_power_notifier);
-		return ret;
-	}
-	return 0;
-}
-module_init(vmwdt_init);
-
-static void __exit vmwdt_exit(void)
-{
-	unregister_pm_notifier(&vmwdt_power_notifier);
-	misc_deregister(&vmwdt_dev);
-}
-module_exit(vmwdt_exit);
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 74ec8fc..daf9441 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1295,9 +1295,10 @@ config WATCHDOG_RTAS
 
 # S390 Architecture
 
-config ZVM_WATCHDOG
-	tristate "z/VM Watchdog Timer"
+config DIAG288_WATCHDOG
+	tristate "System z diag288 Watchdog"
 	depends on S390
+	select WATCHDOG_CORE
 	help
 	  IBM s/390 and zSeries machines running under z/VM 5.1 or later
 	  provide a virtual watchdog timer to their guest that cause a
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 1b5f3d5..5a7fb1f 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -154,6 +154,7 @@ obj-$(CONFIG_MEN_A21_WDT) += mena21_wdt.o
 obj-$(CONFIG_WATCHDOG_RTAS) += wdrtas.o
 
 # S390 Architecture
+obj-$(CONFIG_DIAG288_WATCHDOG) += diag288_wdt.o
 
 # SUPERH (sh + sh64) Architecture
 obj-$(CONFIG_SH_WDT) += shwdt.o
diff --git a/drivers/watchdog/diag288_wdt.c b/drivers/watchdog/diag288_wdt.c
new file mode 100644
index 0000000..d406711
--- /dev/null
+++ b/drivers/watchdog/diag288_wdt.c
@@ -0,0 +1,287 @@
+/*
+ * Watchdog driver for z/VM using the diag 288 interface.
+ *
+ * Under z/VM, expiration of the watchdog will send a "system restart" command
+ * to CP.
+ *
+ * The command can be altered using the module parameter "cmd".
+ *
+ * Copyright IBM Corp. 2004, 2013
+ * Author(s): Arnd Bergmann (arndb@de.ibm.com)
+ *	      Philipp Hachtmann (phacht@de.ibm.com)
+ *
+ */
+
+#define KMSG_COMPONENT "diag288_wdt"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/suspend.h>
+#include <asm/ebcdic.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+#define MAX_CMDLEN 240
+#define DEFAULT_CMD "SYSTEM RESTART"
+
+#define MIN_INTERVAL 15     /* Minimal time supported by diag88 */
+#define MAX_INTERVAL 3600   /* One hour should be enough - pure estimation */
+
+#define WDT_DEFAULT_TIMEOUT 30
+
+/* Function codes - init, change, cancel */
+#define WDT_FUNC_INIT 0
+#define WDT_FUNC_CHANGE 1
+#define WDT_FUNC_CANCEL 2
+#define WDT_FUNC_CONCEAL 0x80000000
+
+static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
+static bool conceal_on;
+static bool nowayout_info = WATCHDOG_NOWAYOUT;
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
+MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
+
+MODULE_DESCRIPTION("System z diag288  Watchdog Timer");
+
+module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
+MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
+
+module_param_named(conceal, conceal_on, bool, 0644);
+MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
+
+module_param_named(nowayout, nowayout_info, bool, 0444);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
+
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("vmwatchdog");
+
+static int __diag288(unsigned int func, unsigned int timeout,
+		     unsigned long action, unsigned int len)
+{
+	register unsigned long __func asm("2") = func;
+	register unsigned long __timeout asm("3") = timeout;
+	register unsigned long __action asm("4") = action;
+	register unsigned long __len asm("5") = len;
+	int err;
+
+	err = -EINVAL;
+	asm volatile(
+		"	diag	%1, %3, 0x288\n"
+		"0:	la	%0, 0\n"
+		"1:\n"
+		EX_TABLE(0b, 1b)
+		: "+d" (err) : "d"(__func), "d"(__timeout),
+		  "d"(__action), "d"(__len) : "1", "cc");
+	return err;
+}
+
+static int __diag288_vm(unsigned int  func, unsigned int timeout,
+			char *cmd, size_t len)
+{
+	return __diag288(func, timeout, virt_to_phys(cmd), len);
+}
+
+static int wdt_start(struct watchdog_device *dev)
+{
+	char *ebc_cmd;
+	size_t len;
+	int ret;
+	unsigned int func;
+
+	ret = -ENODEV;
+
+	if (MACHINE_IS_VM) {
+		ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
+		if (!ebc_cmd)
+			return -ENOMEM;
+		len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
+		ASCEBC(ebc_cmd, MAX_CMDLEN);
+		EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
+
+		func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
+			: WDT_FUNC_INIT;
+		ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
+		WARN_ON(ret != 0);
+		kfree(ebc_cmd);
+	}
+
+	if (ret) {
+		pr_err("The watchdog cannot be activated\n");
+		return ret;
+	}
+	pr_info("The watchdog was activated\n");
+	return 0;
+}
+
+static int wdt_stop(struct watchdog_device *dev)
+{
+	int ret;
+
+	ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
+	pr_info("The watchdog was deactivated\n");
+	return ret;
+}
+
+static int wdt_ping(struct watchdog_device *dev)
+{
+	char *ebc_cmd;
+	size_t len;
+	int ret;
+	unsigned int func;
+
+	ret = -ENODEV;
+
+	if (MACHINE_IS_VM) {
+		ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
+		if (!ebc_cmd)
+			return -ENOMEM;
+		len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
+		ASCEBC(ebc_cmd, MAX_CMDLEN);
+		EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
+
+		/*
+		 * It seems to be ok to z/VM to use the init function to
+		 * retrigger the watchdog.
+		 */
+		func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
+			: WDT_FUNC_INIT;
+
+		ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
+		WARN_ON(ret != 0);
+		kfree(ebc_cmd);
+	}
+
+	if (ret)
+		pr_err("The watchdog timer cannot be started or reset\n");
+	return ret;
+}
+
+static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
+{
+	dev->timeout = new_to;
+	return wdt_ping(dev);
+}
+
+static struct watchdog_ops wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = wdt_start,
+	.stop = wdt_stop,
+	.ping = wdt_ping,
+	.set_timeout = wdt_set_timeout,
+};
+
+static struct watchdog_info wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+	.firmware_version = 0,
+	.identity = "z Watchdog",
+};
+
+static struct watchdog_device wdt_dev = {
+	.parent = NULL,
+	.info = &wdt_info,
+	.ops = &wdt_ops,
+	.bootstatus = 0,
+	.timeout = WDT_DEFAULT_TIMEOUT,
+	.min_timeout = MIN_INTERVAL,
+	.max_timeout = MAX_INTERVAL,
+};
+
+/*
+ * It makes no sense to go into suspend while the watchdog is running.
+ * Depending on the memory size, the watchdog might trigger, while we
+ * are still saving the memory.
+ * We reuse the open flag to ensure that suspend and watchdog open are
+ * exclusive operations
+ */
+static int wdt_suspend(void)
+{
+	if (test_and_set_bit(WDOG_DEV_OPEN, &wdt_dev.status)) {
+		pr_err("Linux cannot be suspended while the watchdog is in use\n");
+		return notifier_from_errno(-EBUSY);
+	}
+	if (test_bit(WDOG_ACTIVE, &wdt_dev.status)) {
+		clear_bit(WDOG_DEV_OPEN, &wdt_dev.status);
+		pr_err("Linux cannot be suspended while the watchdog is in use\n");
+		return notifier_from_errno(-EBUSY);
+	}
+	return NOTIFY_DONE;
+}
+
+static int wdt_resume(void)
+{
+	clear_bit(WDOG_DEV_OPEN, &wdt_dev.status);
+	return NOTIFY_DONE;
+}
+
+static int wdt_power_event(struct notifier_block *this, unsigned long event,
+			   void *ptr)
+{
+	switch (event) {
+	case PM_POST_HIBERNATION:
+	case PM_POST_SUSPEND:
+		return wdt_resume();
+	case PM_HIBERNATION_PREPARE:
+	case PM_SUSPEND_PREPARE:
+		return wdt_suspend();
+	default:
+		return NOTIFY_DONE;
+	}
+}
+
+static struct notifier_block wdt_power_notifier = {
+	.notifier_call = wdt_power_event,
+};
+
+static int __init diag288_init(void)
+{
+	int ret;
+	char ebc_begin[] = {
+		194, 197, 199, 201, 213
+	};
+
+	watchdog_set_nowayout(&wdt_dev, nowayout_info);
+
+	if (MACHINE_IS_VM) {
+		pr_info("The watchdog device driver detected a z/VM environment\n");
+		if (__diag288_vm(WDT_FUNC_INIT, 15,
+				 ebc_begin, sizeof(ebc_begin)) != 0) {
+			pr_err("The watchdog cannot be initialized\n");
+			return -EINVAL;
+		}
+	} else {
+		pr_err("Linux runs in an environment that does not support the diag288 watchdog\n");
+		return -ENODEV;
+	}
+
+	if (__diag288_vm(WDT_FUNC_CANCEL, 0, NULL, 0)) {
+		pr_err("The watchdog cannot be deactivated\n");
+		return -EINVAL;
+	}
+
+	ret = register_pm_notifier(&wdt_power_notifier);
+	if (ret)
+		return ret;
+
+	ret = watchdog_register_device(&wdt_dev);
+	if (ret)
+		unregister_pm_notifier(&wdt_power_notifier);
+
+	return ret;
+}
+
+static void __exit diag288_exit(void)
+{
+	watchdog_unregister_device(&wdt_dev);
+	unregister_pm_notifier(&wdt_power_notifier);
+}
+
+module_init(diag288_init);
+module_exit(diag288_exit);