[deliverable/linux.git] / drivers / watchdog / diag288_wdt.c

/*
 * 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);
	}

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

	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. 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);
	}

	if (MACHINE_IS_LPAR)
		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_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 if (MACHINE_IS_LPAR) {
		pr_info("The watchdog device driver detected an LPAR environment\n");
		if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
			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_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);
Commit	Line	Data
f7a94db4	1	/*
646f919e	2	* Watchdog driver for z/VM and LPAR using the diag 288 interface.
f7a94db4 PH	3	*
	4	* Under z/VM, expiration of the watchdog will send a "system restart" command
	5	* to CP.
	6	*
646f919e PH	7	* The command can be altered using the module parameter "cmd". This is
	8	* not recommended because it's only supported on z/VM but not whith LPAR.
	9	*
	10	* On LPAR, the watchdog will always trigger a system restart. the module
	11	* paramter cmd is meaningless here.
	12	*
f7a94db4 PH	13	*
	14	* Copyright IBM Corp. 2004, 2013
	15	* Author(s): Arnd Bergmann (arndb@de.ibm.com)
	16	* Philipp Hachtmann (phacht@de.ibm.com)
	17	*
	18	*/
	19
	20	#define KMSG_COMPONENT "diag288_wdt"
	21	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	22
	23	#include <linux/init.h>
	24	#include <linux/kernel.h>
	25	#include <linux/module.h>
	26	#include <linux/moduleparam.h>
	27	#include <linux/slab.h>
	28	#include <linux/miscdevice.h>
	29	#include <linux/watchdog.h>
	30	#include <linux/suspend.h>
	31	#include <asm/ebcdic.h>
	32	#include <linux/io.h>
	33	#include <linux/uaccess.h>
	34
	35	#define MAX_CMDLEN 240
	36	#define DEFAULT_CMD "SYSTEM RESTART"
	37
	38	#define MIN_INTERVAL 15 /* Minimal time supported by diag88 */
	39	#define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */
	40
	41	#define WDT_DEFAULT_TIMEOUT 30
	42
	43	/* Function codes - init, change, cancel */
	44	#define WDT_FUNC_INIT 0
	45	#define WDT_FUNC_CHANGE 1
	46	#define WDT_FUNC_CANCEL 2
	47	#define WDT_FUNC_CONCEAL 0x80000000
	48
646f919e PH	49	/* Action codes for LPAR watchdog */
	50	#define LPARWDT_RESTART 0
	51
f7a94db4 PH	52	static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
	53	static bool conceal_on;
	54	static bool nowayout_info = WATCHDOG_NOWAYOUT;
	55
	56	MODULE_LICENSE("GPL");
	57	MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
	58	MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
	59
	60	MODULE_DESCRIPTION("System z diag288 Watchdog Timer");
	61
	62	module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
	63	MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
	64
	65	module_param_named(conceal, conceal_on, bool, 0644);
	66	MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
	67
	68	module_param_named(nowayout, nowayout_info, bool, 0444);
	69	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
	70
	71	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	72	MODULE_ALIAS("vmwatchdog");
	73
	74	static int __diag288(unsigned int func, unsigned int timeout,
	75	unsigned long action, unsigned int len)
	76	{
	77	register unsigned long __func asm("2") = func;
	78	register unsigned long __timeout asm("3") = timeout;
	79	register unsigned long __action asm("4") = action;
	80	register unsigned long __len asm("5") = len;
	81	int err;
	82
	83	err = -EINVAL;
	84	asm volatile(
	85	" diag %1, %3, 0x288\n"
	86	"0: la %0, 0\n"
	87	"1:\n"
	88	EX_TABLE(0b, 1b)
	89	: "+d" (err) : "d"(__func), "d"(__timeout),
	90	"d"(__action), "d"(__len) : "1", "cc");
	91	return err;
	92	}
	93
	94	static int __diag288_vm(unsigned int func, unsigned int timeout,
	95	char *cmd, size_t len)
	96	{
	97	return __diag288(func, timeout, virt_to_phys(cmd), len);
	98	}
	99
646f919e PH	100	static int __diag288_lpar(unsigned int func, unsigned int timeout,
	101	unsigned long action)
	102	{
	103	return __diag288(func, timeout, action, 0);
	104	}
	105
f7a94db4 PH	106	static int wdt_start(struct watchdog_device *dev)
	107	{
	108	char *ebc_cmd;
	109	size_t len;
	110	int ret;
	111	unsigned int func;
	112
	113	ret = -ENODEV;
	114
	115	if (MACHINE_IS_VM) {
	116	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
	117	if (!ebc_cmd)
	118	return -ENOMEM;
	119	len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
	120	ASCEBC(ebc_cmd, MAX_CMDLEN);
	121	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
	122
	123	func = conceal_on ? (WDT_FUNC_INIT \| WDT_FUNC_CONCEAL)
	124	: WDT_FUNC_INIT;
	125	ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
	126	WARN_ON(ret != 0);
	127	kfree(ebc_cmd);
	128	}
	129
646f919e PH	130	if (MACHINE_IS_LPAR) {
	131	ret = __diag288_lpar(WDT_FUNC_INIT,
	132	dev->timeout, LPARWDT_RESTART);
	133	}
	134
f7a94db4 PH	135	if (ret) {
	136	pr_err("The watchdog cannot be activated\n");
	137	return ret;
	138	}
	139	pr_info("The watchdog was activated\n");
	140	return 0;
	141	}
	142
	143	static int wdt_stop(struct watchdog_device *dev)
	144	{
	145	int ret;
	146
	147	ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
	148	pr_info("The watchdog was deactivated\n");
	149	return ret;
	150	}
	151
	152	static int wdt_ping(struct watchdog_device *dev)
	153	{
	154	char *ebc_cmd;
	155	size_t len;
	156	int ret;
	157	unsigned int func;
	158
	159	ret = -ENODEV;
	160
	161	if (MACHINE_IS_VM) {
	162	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
	163	if (!ebc_cmd)
	164	return -ENOMEM;
	165	len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
	166	ASCEBC(ebc_cmd, MAX_CMDLEN);
	167	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
	168
	169	/*
	170	* It seems to be ok to z/VM to use the init function to
646f919e PH	171	* retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
646f919e PH	172	* be used when the watchdog is running.
f7a94db4 PH	173	*/
	174	func = conceal_on ? (WDT_FUNC_INIT \| WDT_FUNC_CONCEAL)
	175	: WDT_FUNC_INIT;
	176
	177	ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
	178	WARN_ON(ret != 0);
	179	kfree(ebc_cmd);
	180	}
	181
646f919e PH	182	if (MACHINE_IS_LPAR)
	183	ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
	184
f7a94db4 PH	185	if (ret)
	186	pr_err("The watchdog timer cannot be started or reset\n");
	187	return ret;
	188	}
	189
	190	static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
	191	{
	192	dev->timeout = new_to;
	193	return wdt_ping(dev);
	194	}
	195
	196	static struct watchdog_ops wdt_ops = {
	197	.owner = THIS_MODULE,
	198	.start = wdt_start,
	199	.stop = wdt_stop,
	200	.ping = wdt_ping,
	201	.set_timeout = wdt_set_timeout,
	202	};
	203
	204	static struct watchdog_info wdt_info = {
	205	.options = WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE,
	206	.firmware_version = 0,
	207	.identity = "z Watchdog",
	208	};
	209
	210	static struct watchdog_device wdt_dev = {
	211	.parent = NULL,
	212	.info = &wdt_info,
	213	.ops = &wdt_ops,
	214	.bootstatus = 0,
	215	.timeout = WDT_DEFAULT_TIMEOUT,
	216	.min_timeout = MIN_INTERVAL,
	217	.max_timeout = MAX_INTERVAL,
	218	};
	219
	220	/*
	221	* It makes no sense to go into suspend while the watchdog is running.
	222	* Depending on the memory size, the watchdog might trigger, while we
	223	* are still saving the memory.
	224	* We reuse the open flag to ensure that suspend and watchdog open are
	225	* exclusive operations
	226	*/
	227	static int wdt_suspend(void)
	228	{
	229	if (test_and_set_bit(WDOG_DEV_OPEN, &wdt_dev.status)) {
	230	pr_err("Linux cannot be suspended while the watchdog is in use\n");
	231	return notifier_from_errno(-EBUSY);
	232	}
	233	if (test_bit(WDOG_ACTIVE, &wdt_dev.status)) {
	234	clear_bit(WDOG_DEV_OPEN, &wdt_dev.status);
	235	pr_err("Linux cannot be suspended while the watchdog is in use\n");
	236	return notifier_from_errno(-EBUSY);
	237	}
	238	return NOTIFY_DONE;
	239	}
	240
	241	static int wdt_resume(void)
	242	{
	243	clear_bit(WDOG_DEV_OPEN, &wdt_dev.status);
	244	return NOTIFY_DONE;
	245	}
	246
	247	static int wdt_power_event(struct notifier_block *this, unsigned long event,
	248	void *ptr)
249	{
250	switch (event) {
251	case PM_POST_HIBERNATION:
252	case PM_POST_SUSPEND:
253	return wdt_resume();
254	case PM_HIBERNATION_PREPARE:
255	case PM_SUSPEND_PREPARE:
256	return wdt_suspend();
257	default:
258	return NOTIFY_DONE;
259	}
260	}
261
262	static struct notifier_block wdt_power_notifier = {
263	.notifier_call = wdt_power_event,
264	};
265
266	static int __init diag288_init(void)
267	{
268	int ret;
269	char ebc_begin[] = {
270	194, 197, 199, 201, 213
271	};
272
273	watchdog_set_nowayout(&wdt_dev, nowayout_info);
274
275	if (MACHINE_IS_VM) {
276	pr_info("The watchdog device driver detected a z/VM environment\n");
277	if (__diag288_vm(WDT_FUNC_INIT, 15,
278	ebc_begin, sizeof(ebc_begin)) != 0) {
279	pr_err("The watchdog cannot be initialized\n");
280	return -EINVAL;
281	}
646f919e PH	282	} else if (MACHINE_IS_LPAR) {
	283	pr_info("The watchdog device driver detected an LPAR environment\n");
	284	if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
	285	pr_err("The watchdog cannot be initialized\n");
	286	return -EINVAL;
	287	}
f7a94db4 PH	288	} else {
	289	pr_err("Linux runs in an environment that does not support the diag288 watchdog\n");
	290	return -ENODEV;
	291	}
	292
646f919e	293	if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) {
f7a94db4 PH	294	pr_err("The watchdog cannot be deactivated\n");
	295	return -EINVAL;
	296	}
	297
	298	ret = register_pm_notifier(&wdt_power_notifier);
	299	if (ret)
	300	return ret;
	301
	302	ret = watchdog_register_device(&wdt_dev);
	303	if (ret)
	304	unregister_pm_notifier(&wdt_power_notifier);
	305
	306	return ret;
	307	}
	308
	309	static void __exit diag288_exit(void)
	310	{
	311	watchdog_unregister_device(&wdt_dev);
	312	unregister_pm_notifier(&wdt_power_notifier);
	313	}
	314
	315	module_init(diag288_init);
	316	module_exit(diag288_exit);