drivers/watchdog/diag288_wdt.c - kernel/msm-4.9 - Gitiles

 /*
  * Watchdog driver for z/VM and LPAR 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". This is
  * not recommended because it's only supported on z/VM but not whith LPAR.
  *
  * On LPAR, the watchdog will always trigger a system restart. the module
  * paramter cmd is meaningless here.
  *
  *
  * 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

 /* Action codes for LPAR watchdog */
 #define LPARWDT_RESTART 0

 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 __diag288_lpar(unsigned int func, unsigned int timeout,
 			  unsigned long action)
 {
 	return __diag288(func, timeout, action, 0);
 }

 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);
 	} else {
 		ret = __diag288_lpar(WDT_FUNC_INIT,
 				     dev->timeout, LPARWDT_RESTART);
 	}

 	if (ret) {
 		pr_err("The watchdog cannot be activated\n");
 		return ret;
 	}
 	return 0;
 }

 static int wdt_stop(struct watchdog_device *dev)
 {
 	int ret;

 	ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
 	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. On LPAR WDT_FUNC_CHANGE must
 		 * be used when the watchdog is running.
 		 */
 		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);
 	} else {
 		ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
 	}

 	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_KEEPALIVEPING | 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) {
 		if (__diag288_vm(WDT_FUNC_INIT, 15,
 				 ebc_begin, sizeof(ebc_begin)) != 0) {
 			pr_err("The watchdog cannot be initialized\n");
 			return -EINVAL;
 		}
 	} else {
 		if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
 			pr_err("The watchdog cannot be initialized\n");
 			return -EINVAL;
 		}
 	}

 	if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 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);
	/*
	* Watchdog driver for z/VM and LPAR 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". This is
	* not recommended because it's only supported on z/VM but not whith LPAR.
	*
	* On LPAR, the watchdog will always trigger a system restart. the module
	* paramter cmd is meaningless here.
	*
	*
	* 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

	/* Action codes for LPAR watchdog */
	#define LPARWDT_RESTART 0

	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 __diag288_lpar(unsigned int func, unsigned int timeout,
	unsigned long action)
	{
	return __diag288(func, timeout, action, 0);
	}

	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);
	} else {
	ret = __diag288_lpar(WDT_FUNC_INIT,
	dev->timeout, LPARWDT_RESTART);
	}

	if (ret) {
	pr_err("The watchdog cannot be activated\n");
	return ret;
	}
	return 0;
	}

	static int wdt_stop(struct watchdog_device *dev)
	{
	int ret;

	ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
	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. On LPAR WDT_FUNC_CHANGE must
	* be used when the watchdog is running.
	*/
	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);
	} else {
	ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
	}

	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_KEEPALIVEPING \| 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) {
	if (__diag288_vm(WDT_FUNC_INIT, 15,
	ebc_begin, sizeof(ebc_begin)) != 0) {
	pr_err("The watchdog cannot be initialized\n");
	return -EINVAL;
	}
	} else {
	if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
	pr_err("The watchdog cannot be initialized\n");
	return -EINVAL;
	}
	}

	if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 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);