[linux-2.6-block.git] / drivers / watchdog / diag288_wdt.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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/watchdog.h>
#include <linux/suspend.h>
#include <asm/ebcdic.h>
#include <asm/diag.h>
#include <linux/io.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("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;

	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;

	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
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
f7a94db4	2	/*
646f919e	3	* Watchdog driver for z/VM and LPAR using the diag 288 interface.
f7a94db4 PH	4	*
	5	* Under z/VM, expiration of the watchdog will send a "system restart" command
	6	* to CP.
	7	*
646f919e PH	8	* The command can be altered using the module parameter "cmd". This is
	9	* not recommended because it's only supported on z/VM but not whith LPAR.
	10	*
	11	* On LPAR, the watchdog will always trigger a system restart. the module
	12	* paramter cmd is meaningless here.
	13	*
f7a94db4 PH	14	*
	15	* Copyright IBM Corp. 2004, 2013
	16	* Author(s): Arnd Bergmann (arndb@de.ibm.com)
	17	* Philipp Hachtmann (phacht@de.ibm.com)
	18	*
	19	*/
	20
	21	#define KMSG_COMPONENT "diag288_wdt"
	22	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	23
	24	#include <linux/init.h>
	25	#include <linux/kernel.h>
	26	#include <linux/module.h>
	27	#include <linux/moduleparam.h>
	28	#include <linux/slab.h>
f7a94db4 PH	29	#include <linux/watchdog.h>
	30	#include <linux/suspend.h>
	31	#include <asm/ebcdic.h>
1ec2772e	32	#include <asm/diag.h>
f7a94db4	33	#include <linux/io.h>
f7a94db4 PH	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
f7a94db4 PH	71	MODULE_ALIAS("vmwatchdog");
	72
	73	static int __diag288(unsigned int func, unsigned int timeout,
	74	unsigned long action, unsigned int len)
	75	{
	76	register unsigned long __func asm("2") = func;
	77	register unsigned long __timeout asm("3") = timeout;
	78	register unsigned long __action asm("4") = action;
	79	register unsigned long __len asm("5") = len;
	80	int err;
	81
	82	err = -EINVAL;
	83	asm volatile(
	84	" diag %1, %3, 0x288\n"
	85	"0: la %0, 0\n"
	86	"1:\n"
	87	EX_TABLE(0b, 1b)
	88	: "+d" (err) : "d"(__func), "d"(__timeout),
	89	"d"(__action), "d"(__len) : "1", "cc");
	90	return err;
	91	}
	92
	93	static int __diag288_vm(unsigned int func, unsigned int timeout,
	94	char *cmd, size_t len)
	95	{
1ec2772e	96	diag_stat_inc(DIAG_STAT_X288);
f7a94db4 PH	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	{
1ec2772e	103	diag_stat_inc(DIAG_STAT_X288);
646f919e PH	104	return __diag288(func, timeout, action, 0);
	105	}
	106
e7d162fa GR	107	static unsigned long wdt_status;
	108
	109	#define DIAG_WDOG_BUSY 0
	110
f7a94db4 PH	111	static int wdt_start(struct watchdog_device *dev)
	112	{
	113	char *ebc_cmd;
	114	size_t len;
	115	int ret;
	116	unsigned int func;
	117
e7d162fa GR	118	if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status))
	119	return -EBUSY;
	120
f7a94db4 PH	121	if (MACHINE_IS_VM) {
f7a94db4 PH	122	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
e7d162fa GR	123	if (!ebc_cmd) {
e7d162fa GR	124	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
f7a94db4	125	return -ENOMEM;
e7d162fa	126	}
f7a94db4 PH	127	len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
	128	ASCEBC(ebc_cmd, MAX_CMDLEN);
	129	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
	130
	131	func = conceal_on ? (WDT_FUNC_INIT \| WDT_FUNC_CONCEAL)
	132	: WDT_FUNC_INIT;
	133	ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
	134	WARN_ON(ret != 0);
	135	kfree(ebc_cmd);
b2527d20	136	} else {
646f919e PH	137	ret = __diag288_lpar(WDT_FUNC_INIT,
	138	dev->timeout, LPARWDT_RESTART);
	139	}
	140
f7a94db4 PH	141	if (ret) {
f7a94db4 PH	142	pr_err("The watchdog cannot be activated\n");
e7d162fa	143	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
f7a94db4 PH	144	return ret;
f7a94db4 PH	145	}
f7a94db4 PH	146	return 0;
	147	}
	148
	149	static int wdt_stop(struct watchdog_device *dev)
	150	{
	151	int ret;
	152
1ec2772e	153	diag_stat_inc(DIAG_STAT_X288);
f7a94db4	154	ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
e7d162fa GR	155
	156	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
	157
f7a94db4 PH	158	return ret;
	159	}
	160
	161	static int wdt_ping(struct watchdog_device *dev)
	162	{
	163	char *ebc_cmd;
	164	size_t len;
	165	int ret;
	166	unsigned int func;
	167
f7a94db4 PH	168	if (MACHINE_IS_VM) {
	169	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
	170	if (!ebc_cmd)
	171	return -ENOMEM;
	172	len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
	173	ASCEBC(ebc_cmd, MAX_CMDLEN);
	174	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
	175
	176	/*
	177	* It seems to be ok to z/VM to use the init function to
646f919e PH	178	* retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
646f919e PH	179	* be used when the watchdog is running.
f7a94db4 PH	180	*/
	181	func = conceal_on ? (WDT_FUNC_INIT \| WDT_FUNC_CONCEAL)
	182	: WDT_FUNC_INIT;
	183
	184	ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
	185	WARN_ON(ret != 0);
	186	kfree(ebc_cmd);
b2527d20	187	} else {
646f919e	188	ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
b2527d20	189	}
646f919e	190
f7a94db4 PH	191	if (ret)
	192	pr_err("The watchdog timer cannot be started or reset\n");
	193	return ret;
	194	}
	195
	196	static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
	197	{
	198	dev->timeout = new_to;
	199	return wdt_ping(dev);
	200	}
	201
b893e344	202	static const struct watchdog_ops wdt_ops = {
f7a94db4 PH	203	.owner = THIS_MODULE,
	204	.start = wdt_start,
	205	.stop = wdt_stop,
	206	.ping = wdt_ping,
	207	.set_timeout = wdt_set_timeout,
	208	};
	209
323edb2e	210	static const struct watchdog_info wdt_info = {
9ec6cb80	211	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
f7a94db4 PH	212	.firmware_version = 0,
	213	.identity = "z Watchdog",
	214	};
	215
	216	static struct watchdog_device wdt_dev = {
	217	.parent = NULL,
	218	.info = &wdt_info,
	219	.ops = &wdt_ops,
	220	.bootstatus = 0,
	221	.timeout = WDT_DEFAULT_TIMEOUT,
	222	.min_timeout = MIN_INTERVAL,
	223	.max_timeout = MAX_INTERVAL,
	224	};
	225
	226	/*
	227	* It makes no sense to go into suspend while the watchdog is running.
	228	* Depending on the memory size, the watchdog might trigger, while we
	229	* are still saving the memory.
f7a94db4 PH	230	*/
	231	static int wdt_suspend(void)
	232	{
e7d162fa	233	if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) {
f7a94db4 PH	234	pr_err("Linux cannot be suspended while the watchdog is in use\n");
	235	return notifier_from_errno(-EBUSY);
	236	}
	237	return NOTIFY_DONE;
	238	}
	239
	240	static int wdt_resume(void)
	241	{
e7d162fa	242	clear_bit(DIAG_WDOG_BUSY, &wdt_status);
f7a94db4 PH	243	return NOTIFY_DONE;
	244	}
	245
	246	static int wdt_power_event(struct notifier_block *this, unsigned long event,
	247	void *ptr)
	248	{
	249	switch (event) {
	250	case PM_POST_HIBERNATION:
	251	case PM_POST_SUSPEND:
	252	return wdt_resume();
	253	case PM_HIBERNATION_PREPARE:
	254	case PM_SUSPEND_PREPARE:
	255	return wdt_suspend();
	256	default:
	257	return NOTIFY_DONE;
	258	}
	259	}
	260
	261	static struct notifier_block wdt_power_notifier = {
	262	.notifier_call = wdt_power_event,
	263	};
	264
	265	static int __init diag288_init(void)
	266	{
	267	int ret;
	268	char ebc_begin[] = {
	269	194, 197, 199, 201, 213
	270	};
	271
	272	watchdog_set_nowayout(&wdt_dev, nowayout_info);
	273
	274	if (MACHINE_IS_VM) {
f7a94db4 PH	275	if (__diag288_vm(WDT_FUNC_INIT, 15,
	276	ebc_begin, sizeof(ebc_begin)) != 0) {
	277	pr_err("The watchdog cannot be initialized\n");
	278	return -EINVAL;
	279	}
b2527d20	280	} else {
646f919e PH	281	if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
	282	pr_err("The watchdog cannot be initialized\n");
	283	return -EINVAL;
	284	}
f7a94db4 PH	285	}
f7a94db4 PH	286
646f919e	287	if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) {
f7a94db4 PH	288	pr_err("The watchdog cannot be deactivated\n");
	289	return -EINVAL;
	290	}
	291
	292	ret = register_pm_notifier(&wdt_power_notifier);
	293	if (ret)
	294	return ret;
	295
	296	ret = watchdog_register_device(&wdt_dev);
	297	if (ret)
	298	unregister_pm_notifier(&wdt_power_notifier);
	299
	300	return ret;
	301	}
	302
	303	static void __exit diag288_exit(void)
	304	{
	305	watchdog_unregister_device(&wdt_dev);
	306	unregister_pm_notifier(&wdt_power_notifier);
	307	}
	308
	309	module_init(diag288_init);
	310	module_exit(diag288_exit);