[people/arne_f/kernel.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 <asm/diag.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)
{
	diag_stat_inc(DIAG_STAT_X288);
	return __diag288(func, timeout, virt_to_phys(cmd), len);
}

static int __diag288_lpar(unsigned int func, unsigned int timeout,
			  unsigned long action)
{
	diag_stat_inc(DIAG_STAT_X288);
	return __diag288(func, timeout, action, 0);
}

static unsigned long wdt_status;

#define DIAG_WDOG_BUSY	0

static int wdt_start(struct watchdog_device *dev)
{
	char *ebc_cmd;
	size_t len;
	int ret;
	unsigned int func;

	if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status))
		return -EBUSY;

	ret = -ENODEV;

	if (MACHINE_IS_VM) {
		ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
		if (!ebc_cmd) {
			clear_bit(DIAG_WDOG_BUSY, &wdt_status);
			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");
		clear_bit(DIAG_WDOG_BUSY, &wdt_status);
		return ret;
	}
	return 0;
}

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

	diag_stat_inc(DIAG_STAT_X288);
	ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);

	clear_bit(DIAG_WDOG_BUSY, &wdt_status);

	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 const struct watchdog_ops wdt_ops = {
	.owner = THIS_MODULE,
	.start = wdt_start,
	.stop = wdt_stop,
	.ping = wdt_ping,
	.set_timeout = wdt_set_timeout,
};

static const 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.
 */
static int wdt_suspend(void)
{
	if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_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(DIAG_WDOG_BUSY, &wdt_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);
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>
1ec2772e	32	#include <asm/diag.h>
f7a94db4 PH	33	#include <linux/io.h>
	34	#include <linux/uaccess.h>
	35
	36	#define MAX_CMDLEN 240
	37	#define DEFAULT_CMD "SYSTEM RESTART"
	38
	39	#define MIN_INTERVAL 15 /* Minimal time supported by diag88 */
	40	#define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */
	41
	42	#define WDT_DEFAULT_TIMEOUT 30
	43
	44	/* Function codes - init, change, cancel */
	45	#define WDT_FUNC_INIT 0
	46	#define WDT_FUNC_CHANGE 1
	47	#define WDT_FUNC_CANCEL 2
	48	#define WDT_FUNC_CONCEAL 0x80000000
	49
646f919e PH	50	/* Action codes for LPAR watchdog */
	51	#define LPARWDT_RESTART 0
	52
f7a94db4 PH	53	static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
	54	static bool conceal_on;
	55	static bool nowayout_info = WATCHDOG_NOWAYOUT;
	56
	57	MODULE_LICENSE("GPL");
	58	MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
	59	MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
	60
	61	MODULE_DESCRIPTION("System z diag288 Watchdog Timer");
	62
	63	module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
	64	MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
	65
	66	module_param_named(conceal, conceal_on, bool, 0644);
	67	MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
	68
	69	module_param_named(nowayout, nowayout_info, bool, 0444);
	70	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
	71
	72	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	73	MODULE_ALIAS("vmwatchdog");
	74
	75	static int __diag288(unsigned int func, unsigned int timeout,
	76	unsigned long action, unsigned int len)
	77	{
	78	register unsigned long __func asm("2") = func;
	79	register unsigned long __timeout asm("3") = timeout;
	80	register unsigned long __action asm("4") = action;
	81	register unsigned long __len asm("5") = len;
	82	int err;
	83
	84	err = -EINVAL;
	85	asm volatile(
	86	" diag %1, %3, 0x288\n"
	87	"0: la %0, 0\n"
	88	"1:\n"
	89	EX_TABLE(0b, 1b)
	90	: "+d" (err) : "d"(__func), "d"(__timeout),
	91	"d"(__action), "d"(__len) : "1", "cc");
	92	return err;
	93	}
	94
	95	static int __diag288_vm(unsigned int func, unsigned int timeout,
	96	char *cmd, size_t len)
	97	{
1ec2772e	98	diag_stat_inc(DIAG_STAT_X288);
f7a94db4 PH	99	return __diag288(func, timeout, virt_to_phys(cmd), len);
	100	}
	101
646f919e PH	102	static int __diag288_lpar(unsigned int func, unsigned int timeout,
	103	unsigned long action)
	104	{
1ec2772e	105	diag_stat_inc(DIAG_STAT_X288);
646f919e PH	106	return __diag288(func, timeout, action, 0);
	107	}
	108
e7d162fa GR	109	static unsigned long wdt_status;
	110
	111	#define DIAG_WDOG_BUSY 0
	112
f7a94db4 PH	113	static int wdt_start(struct watchdog_device *dev)
	114	{
	115	char *ebc_cmd;
	116	size_t len;
	117	int ret;
	118	unsigned int func;
	119
e7d162fa GR	120	if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status))
	121	return -EBUSY;
	122
f7a94db4 PH	123	ret = -ENODEV;
	124
	125	if (MACHINE_IS_VM) {
	126	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
e7d162fa GR	127	if (!ebc_cmd) {
e7d162fa GR	128	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
f7a94db4	129	return -ENOMEM;
e7d162fa	130	}
f7a94db4 PH	131	len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
	132	ASCEBC(ebc_cmd, MAX_CMDLEN);
	133	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
	134
	135	func = conceal_on ? (WDT_FUNC_INIT \| WDT_FUNC_CONCEAL)
	136	: WDT_FUNC_INIT;
	137	ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
	138	WARN_ON(ret != 0);
	139	kfree(ebc_cmd);
b2527d20	140	} else {
646f919e PH	141	ret = __diag288_lpar(WDT_FUNC_INIT,
	142	dev->timeout, LPARWDT_RESTART);
	143	}
	144
f7a94db4 PH	145	if (ret) {
f7a94db4 PH	146	pr_err("The watchdog cannot be activated\n");
e7d162fa	147	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
f7a94db4 PH	148	return ret;
f7a94db4 PH	149	}
f7a94db4 PH	150	return 0;
	151	}
	152
	153	static int wdt_stop(struct watchdog_device *dev)
	154	{
	155	int ret;
	156
1ec2772e	157	diag_stat_inc(DIAG_STAT_X288);
f7a94db4	158	ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
e7d162fa GR	159
	160	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
	161
f7a94db4 PH	162	return ret;
	163	}
	164
	165	static int wdt_ping(struct watchdog_device *dev)
	166	{
	167	char *ebc_cmd;
	168	size_t len;
	169	int ret;
	170	unsigned int func;
	171
	172	ret = -ENODEV;
	173
	174	if (MACHINE_IS_VM) {
	175	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
	176	if (!ebc_cmd)
	177	return -ENOMEM;
	178	len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
	179	ASCEBC(ebc_cmd, MAX_CMDLEN);
	180	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
	181
	182	/*
	183	* It seems to be ok to z/VM to use the init function to
646f919e PH	184	* retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
646f919e PH	185	* be used when the watchdog is running.
f7a94db4 PH	186	*/
	187	func = conceal_on ? (WDT_FUNC_INIT \| WDT_FUNC_CONCEAL)
	188	: WDT_FUNC_INIT;
	189
	190	ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
	191	WARN_ON(ret != 0);
	192	kfree(ebc_cmd);
b2527d20	193	} else {
646f919e	194	ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
b2527d20	195	}
646f919e	196
f7a94db4 PH	197	if (ret)
	198	pr_err("The watchdog timer cannot be started or reset\n");
	199	return ret;
	200	}
	201
	202	static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
	203	{
	204	dev->timeout = new_to;
	205	return wdt_ping(dev);
	206	}
	207
b893e344	208	static const struct watchdog_ops wdt_ops = {
f7a94db4 PH	209	.owner = THIS_MODULE,
	210	.start = wdt_start,
	211	.stop = wdt_stop,
	212	.ping = wdt_ping,
	213	.set_timeout = wdt_set_timeout,
	214	};
	215
323edb2e	216	static const struct watchdog_info wdt_info = {
9ec6cb80	217	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
f7a94db4 PH	218	.firmware_version = 0,
	219	.identity = "z Watchdog",
	220	};
	221
	222	static struct watchdog_device wdt_dev = {
	223	.parent = NULL,
	224	.info = &wdt_info,
	225	.ops = &wdt_ops,
	226	.bootstatus = 0,
	227	.timeout = WDT_DEFAULT_TIMEOUT,
	228	.min_timeout = MIN_INTERVAL,
	229	.max_timeout = MAX_INTERVAL,
	230	};
	231
	232	/*
	233	* It makes no sense to go into suspend while the watchdog is running.
	234	* Depending on the memory size, the watchdog might trigger, while we
	235	* are still saving the memory.
f7a94db4 PH	236	*/
	237	static int wdt_suspend(void)
	238	{
e7d162fa	239	if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) {
f7a94db4 PH	240	pr_err("Linux cannot be suspended while the watchdog is in use\n");
	241	return notifier_from_errno(-EBUSY);
	242	}
	243	return NOTIFY_DONE;
	244	}
	245
	246	static int wdt_resume(void)
	247	{
e7d162fa	248	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
f7a94db4 PH	249	return NOTIFY_DONE;
	250	}
	251
	252	static int wdt_power_event(struct notifier_block *this, unsigned long event,
	253	void *ptr)
	254	{
	255	switch (event) {
	256	case PM_POST_HIBERNATION:
	257	case PM_POST_SUSPEND:
	258	return wdt_resume();
	259	case PM_HIBERNATION_PREPARE:
	260	case PM_SUSPEND_PREPARE:
	261	return wdt_suspend();
	262	default:
	263	return NOTIFY_DONE;
	264	}
	265	}
	266
	267	static struct notifier_block wdt_power_notifier = {
	268	.notifier_call = wdt_power_event,
	269	};
	270
	271	static int __init diag288_init(void)
	272	{
	273	int ret;
	274	char ebc_begin[] = {
	275	194, 197, 199, 201, 213
	276	};
	277
	278	watchdog_set_nowayout(&wdt_dev, nowayout_info);
	279
	280	if (MACHINE_IS_VM) {
f7a94db4 PH	281	if (__diag288_vm(WDT_FUNC_INIT, 15,
	282	ebc_begin, sizeof(ebc_begin)) != 0) {
	283	pr_err("The watchdog cannot be initialized\n");
	284	return -EINVAL;
	285	}
b2527d20	286	} else {
646f919e PH	287	if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
	288	pr_err("The watchdog cannot be initialized\n");
	289	return -EINVAL;
	290	}
f7a94db4 PH	291	}
f7a94db4 PH	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);