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

// SPDX-License-Identifier: GPL-2.0-or-later
/* Watchdog timer for machines with the CS5535/CS5536 companion chip
 *
 * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
 * Copyright (C) 2009  Andres Salomon <dilinger@collabora.co.uk>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/uaccess.h>

#include <linux/cs5535.h>

#define GEODEWDT_HZ 500
#define GEODEWDT_SCALE 6
#define GEODEWDT_MAX_SECONDS 131

#define WDT_FLAGS_OPEN 1
#define WDT_FLAGS_ORPHAN 2

#define DRV_NAME "geodewdt"
#define WATCHDOG_NAME "Geode GX/LX WDT"
#define WATCHDOG_TIMEOUT 60

static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. 1<= timeout <=131, default="
				__MODULE_STRING(WATCHDOG_TIMEOUT) ".");

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
	"Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static struct platform_device *geodewdt_platform_device;
static unsigned long wdt_flags;
static struct cs5535_mfgpt_timer *wdt_timer;
static int safe_close;

static void geodewdt_ping(void)
{
	/* Stop the counter */
	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);

	/* Reset the counter */
	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);

	/* Enable the counter */
	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
}

static void geodewdt_disable(void)
{
	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
}

static int geodewdt_set_heartbeat(int val)
{
	if (val < 1 || val > GEODEWDT_MAX_SECONDS)
		return -EINVAL;

	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);

	timeout = val;
	return 0;
}

static int geodewdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
		return -EBUSY;

	if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
		__module_get(THIS_MODULE);

	geodewdt_ping();
	return stream_open(inode, file);
}

static int geodewdt_release(struct inode *inode, struct file *file)
{
	if (safe_close) {
		geodewdt_disable();
		module_put(THIS_MODULE);
	} else {
		pr_crit("Unexpected close - watchdog is not stopping\n");
		geodewdt_ping();

		set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
	}

	clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
	safe_close = 0;
	return 0;
}

static ssize_t geodewdt_write(struct file *file, const char __user *data,
				size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;
			safe_close = 0;

			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, data + i))
					return -EFAULT;

				if (c == 'V')
					safe_close = 1;
			}
		}

		geodewdt_ping();
	}
	return len;
}

static long geodewdt_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int interval;

	static const struct watchdog_info ident = {
		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
		| WDIOF_MAGICCLOSE,
		.firmware_version =     1,
		.identity =             WATCHDOG_NAME,
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident,
				    sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);

	case WDIOC_SETOPTIONS:
	{
		int options, ret = -EINVAL;

		if (get_user(options, p))
			return -EFAULT;

		if (options & WDIOS_DISABLECARD) {
			geodewdt_disable();
			ret = 0;
		}

		if (options & WDIOS_ENABLECARD) {
			geodewdt_ping();
			ret = 0;
		}

		return ret;
	}
	case WDIOC_KEEPALIVE:
		geodewdt_ping();
		return 0;

	case WDIOC_SETTIMEOUT:
		if (get_user(interval, p))
			return -EFAULT;

		if (geodewdt_set_heartbeat(interval))
			return -EINVAL;
	/* Fall through */
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, p);

	default:
		return -ENOTTY;
	}

	return 0;
}

static const struct file_operations geodewdt_fops = {
	.owner          = THIS_MODULE,
	.llseek         = no_llseek,
	.write          = geodewdt_write,
	.unlocked_ioctl = geodewdt_ioctl,
	.open           = geodewdt_open,
	.release        = geodewdt_release,
};

static struct miscdevice geodewdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &geodewdt_fops,
};

static int __init geodewdt_probe(struct platform_device *dev)
{
	int ret;

	wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
	if (!wdt_timer) {
		pr_err("No timers were available\n");
		return -ENODEV;
	}

	/* Set up the timer */

	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
			  GEODEWDT_SCALE | (3 << 8));

	/* Set up comparator 2 to reset when the event fires */
	cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);

	/* Set up the initial timeout */

	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
		timeout * GEODEWDT_HZ);

	ret = misc_register(&geodewdt_miscdev);

	return ret;
}

static int geodewdt_remove(struct platform_device *dev)
{
	misc_deregister(&geodewdt_miscdev);
	return 0;
}

static void geodewdt_shutdown(struct platform_device *dev)
{
	geodewdt_disable();
}

static struct platform_driver geodewdt_driver = {
	.remove		= geodewdt_remove,
	.shutdown	= geodewdt_shutdown,
	.driver		= {
		.name	= DRV_NAME,
	},
};

static int __init geodewdt_init(void)
{
	int ret;

	geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
								-1, NULL, 0);
	if (IS_ERR(geodewdt_platform_device))
		return PTR_ERR(geodewdt_platform_device);

	ret = platform_driver_probe(&geodewdt_driver, geodewdt_probe);
	if (ret)
		goto err;

	return 0;
err:
	platform_device_unregister(geodewdt_platform_device);
	return ret;
}

static void __exit geodewdt_exit(void)
{
	platform_device_unregister(geodewdt_platform_device);
	platform_driver_unregister(&geodewdt_driver);
}

module_init(geodewdt_init);
module_exit(geodewdt_exit);

MODULE_AUTHOR("Advanced Micro Devices, Inc");
MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
9b0fd114	2	/* Watchdog timer for machines with the CS5535/CS5536 companion chip
0b36086b JC	3	*
0b36086b JC	4	* Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
9b0fd114	5	* Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk>
0b36086b JC	6	*/
0b36086b JC	7
27c766aa	8	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0b36086b JC	9
	10	#include <linux/module.h>
	11	#include <linux/moduleparam.h>
	12	#include <linux/types.h>
	13	#include <linux/miscdevice.h>
	14	#include <linux/watchdog.h>
	15	#include <linux/fs.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/reboot.h>
089ab079	18	#include <linux/uaccess.h>
0b36086b	19
9b0fd114	20	#include <linux/cs5535.h>
0b36086b JC	21
	22	#define GEODEWDT_HZ 500
	23	#define GEODEWDT_SCALE 6
	24	#define GEODEWDT_MAX_SECONDS 131
	25
	26	#define WDT_FLAGS_OPEN 1
	27	#define WDT_FLAGS_ORPHAN 2
	28
	29	#define DRV_NAME "geodewdt"
	30	#define WATCHDOG_NAME "Geode GX/LX WDT"
	31	#define WATCHDOG_TIMEOUT 60
	32
	33	static int timeout = WATCHDOG_TIMEOUT;
	34	module_param(timeout, int, 0);
143a2e54 WVS	35	MODULE_PARM_DESC(timeout,
	36	"Watchdog timeout in seconds. 1<= timeout <=131, default="
	37	__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
0b36086b	38
86a1e189 WVS	39	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	40	module_param(nowayout, bool, 0);
143a2e54 WVS	41	MODULE_PARM_DESC(nowayout,
	42	"Watchdog cannot be stopped once started (default="
	43	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
0b36086b JC	44
	45	static struct platform_device *geodewdt_platform_device;
	46	static unsigned long wdt_flags;
9b0fd114	47	static struct cs5535_mfgpt_timer *wdt_timer;
0b36086b JC	48	static int safe_close;
	49
	50	static void geodewdt_ping(void)
	51	{
	52	/* Stop the counter */
9b0fd114	53	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
0b36086b JC	54
0b36086b JC	55	/* Reset the counter */
9b0fd114	56	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
0b36086b JC	57
0b36086b JC	58	/* Enable the counter */
9b0fd114	59	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
0b36086b JC	60	}
	61
	62	static void geodewdt_disable(void)
	63	{
9b0fd114 AS	64	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
9b0fd114 AS	65	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
0b36086b JC	66	}
	67
	68	static int geodewdt_set_heartbeat(int val)
	69	{
	70	if (val < 1 \|\| val > GEODEWDT_MAX_SECONDS)
	71	return -EINVAL;
	72
9b0fd114 AS	73	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
	74	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
	75	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
	76	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
0b36086b JC	77
	78	timeout = val;
	79	return 0;
	80	}
	81
7944d3a5	82	static int geodewdt_open(struct inode inode, struct file file)
0b36086b	83	{
7944d3a5 WVS	84	if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
7944d3a5 WVS	85	return -EBUSY;
0b36086b	86
7944d3a5 WVS	87	if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
7944d3a5 WVS	88	__module_get(THIS_MODULE);
0b36086b JC	89
0b36086b JC	90	geodewdt_ping();
c5bf68fe	91	return stream_open(inode, file);
0b36086b JC	92	}
0b36086b JC	93
7944d3a5	94	static int geodewdt_release(struct inode inode, struct file file)
0b36086b JC	95	{
	96	if (safe_close) {
	97	geodewdt_disable();
	98	module_put(THIS_MODULE);
7944d3a5	99	} else {
27c766aa	100	pr_crit("Unexpected close - watchdog is not stopping\n");
0b36086b JC	101	geodewdt_ping();
	102
	103	set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
	104	}
	105
	106	clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
	107	safe_close = 0;
	108	return 0;
	109	}
	110
7944d3a5 WVS	111	static ssize_t geodewdt_write(struct file file, const char __user data,
7944d3a5 WVS	112	size_t len, loff_t *ppos)
0b36086b	113	{
7944d3a5	114	if (len) {
0b36086b JC	115	if (!nowayout) {
	116	size_t i;
	117	safe_close = 0;
	118
	119	for (i = 0; i != len; i++) {
	120	char c;
	121
	122	if (get_user(c, data + i))
	123	return -EFAULT;
	124
	125	if (c == 'V')
	126	safe_close = 1;
	127	}
	128	}
	129
	130	geodewdt_ping();
	131	}
	132	return len;
	133	}
	134
7275fc8c WVS	135	static long geodewdt_ioctl(struct file *file, unsigned int cmd,
7275fc8c WVS	136	unsigned long arg)
0b36086b JC	137	{
	138	void __user argp = (void __user )arg;
	139	int __user *p = argp;
	140	int interval;
	141
42747d71	142	static const struct watchdog_info ident = {
0b36086b JC	143	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING
	144	\| WDIOF_MAGICCLOSE,
	145	.firmware_version = 1,
	146	.identity = WATCHDOG_NAME,
7944d3a5	147	};
0b36086b	148
5eb82498	149	switch (cmd) {
0b36086b JC	150	case WDIOC_GETSUPPORT:
	151	return copy_to_user(argp, &ident,
	152	sizeof(ident)) ? -EFAULT : 0;
	153	break;
	154
	155	case WDIOC_GETSTATUS:
	156	case WDIOC_GETBOOTSTATUS:
	157	return put_user(0, p);
	158
0b36086b JC	159	case WDIOC_SETOPTIONS:
	160	{
	161	int options, ret = -EINVAL;
	162
	163	if (get_user(options, p))
	164	return -EFAULT;
	165
	166	if (options & WDIOS_DISABLECARD) {
	167	geodewdt_disable();
	168	ret = 0;
	169	}
	170
	171	if (options & WDIOS_ENABLECARD) {
	172	geodewdt_ping();
	173	ret = 0;
	174	}
	175
	176	return ret;
	177	}
0c06090c WVS	178	case WDIOC_KEEPALIVE:
	179	geodewdt_ping();
	180	return 0;
	181
	182	case WDIOC_SETTIMEOUT:
	183	if (get_user(interval, p))
	184	return -EFAULT;
	185
	186	if (geodewdt_set_heartbeat(interval))
	187	return -EINVAL;
	188	/* Fall through */
	189	case WDIOC_GETTIMEOUT:
	190	return put_user(timeout, p);
	191
0b36086b JC	192	default:
	193	return -ENOTTY;
	194	}
	195
	196	return 0;
	197	}
	198
	199	static const struct file_operations geodewdt_fops = {
7944d3a5 WVS	200	.owner = THIS_MODULE,
	201	.llseek = no_llseek,
	202	.write = geodewdt_write,
7275fc8c	203	.unlocked_ioctl = geodewdt_ioctl,
7944d3a5 WVS	204	.open = geodewdt_open,
7944d3a5 WVS	205	.release = geodewdt_release,
0b36086b JC	206	};
	207
	208	static struct miscdevice geodewdt_miscdev = {
	209	.minor = WATCHDOG_MINOR,
	210	.name = "watchdog",
7944d3a5	211	.fops = &geodewdt_fops,
0b36086b JC	212	};
0b36086b JC	213
78411be4	214	static int __init geodewdt_probe(struct platform_device *dev)
0b36086b	215	{
9b0fd114	216	int ret;
0b36086b	217
9b0fd114 AS	218	wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
9b0fd114 AS	219	if (!wdt_timer) {
27c766aa	220	pr_err("No timers were available\n");
0b36086b JC	221	return -ENODEV;
	222	}
	223
0b36086b JC	224	/* Set up the timer */
0b36086b JC	225
9b0fd114	226	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
0b36086b JC	227	GEODEWDT_SCALE \| (3 << 8));
	228
	229	/* Set up comparator 2 to reset when the event fires */
9b0fd114	230	cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
0b36086b JC	231
	232	/* Set up the initial timeout */
	233
9b0fd114	234	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
0b36086b JC	235	timeout * GEODEWDT_HZ);
	236
	237	ret = misc_register(&geodewdt_miscdev);
	238
	239	return ret;
	240	}
	241
4b12b896	242	static int geodewdt_remove(struct platform_device *dev)
0b36086b JC	243	{
	244	misc_deregister(&geodewdt_miscdev);
	245	return 0;
	246	}
	247
7944d3a5	248	static void geodewdt_shutdown(struct platform_device *dev)
0b36086b JC	249	{
	250	geodewdt_disable();
	251	}
	252
	253	static struct platform_driver geodewdt_driver = {
82268714	254	.remove = geodewdt_remove,
0b36086b JC	255	.shutdown = geodewdt_shutdown,
0b36086b JC	256	.driver = {
0b36086b JC	257	.name = DRV_NAME,
	258	},
	259	};
	260
7944d3a5	261	static int __init geodewdt_init(void)
0b36086b JC	262	{
	263	int ret;
	264
143a2e54 WVS	265	geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
143a2e54 WVS	266	-1, NULL, 0);
78411be4 JD	267	if (IS_ERR(geodewdt_platform_device))
	268	return PTR_ERR(geodewdt_platform_device);
	269
	270	ret = platform_driver_probe(&geodewdt_driver, geodewdt_probe);
	271	if (ret)
0b36086b	272	goto err;
0b36086b JC	273
	274	return 0;
	275	err:
78411be4	276	platform_device_unregister(geodewdt_platform_device);
0b36086b JC	277	return ret;
	278	}
	279
7944d3a5	280	static void __exit geodewdt_exit(void)
0b36086b JC	281	{
	282	platform_device_unregister(geodewdt_platform_device);
	283	platform_driver_unregister(&geodewdt_driver);
	284	}
	285
	286	module_init(geodewdt_init);
	287	module_exit(geodewdt_exit);
	288
	289	MODULE_AUTHOR("Advanced Micro Devices, Inc");
	290	MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
	291	MODULE_LICENSE("GPL");