[net-next-2.6.git] / drivers / watchdog / txx9wdt.c

/*
 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
 *
 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#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/reboot.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <asm/txx9tmr.h>

#define TIMER_MARGIN	60		/* Default is 60 seconds */

static int timeout = TIMER_MARGIN;	/* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. "
	"(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
	"default=" __MODULE_STRING(TIMER_MARGIN) ")");

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

#define WD_TIMER_CCD	7	/* 1/256 */
#define WD_TIMER_CLK	(clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
#define WD_MAX_TIMEOUT	((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)

static unsigned long txx9wdt_alive;
static int expect_close;
static struct txx9_tmr_reg __iomem *txx9wdt_reg;
static struct clk *txx9_imclk;

static void txx9wdt_ping(void)
{
	__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
}

static void txx9wdt_start(void)
{
	__raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
	__raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
	__raw_writel(0, &txx9wdt_reg->tisr);	/* clear pending interrupt */
	__raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
		     &txx9wdt_reg->tcr);
	__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
}

static void txx9wdt_stop(void)
{
	__raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
	__raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
		     &txx9wdt_reg->tcr);
}

static int txx9wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &txx9wdt_alive))
		return -EBUSY;

	if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
		clear_bit(0, &txx9wdt_alive);
		return -EBUSY;
	}

	if (nowayout)
		__module_get(THIS_MODULE);

	txx9wdt_start();
	return nonseekable_open(inode, file);
}

static int txx9wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close)
		txx9wdt_stop();
	else {
		printk(KERN_CRIT "txx9wdt: "
		       "Unexpected close, not stopping watchdog!\n");
		txx9wdt_ping();
	}
	clear_bit(0, &txx9wdt_alive);
	expect_close = 0;
	return 0;
}

static ssize_t txx9wdt_write(struct file *file, const char __user *data,
			     size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			expect_close = 0;
			for (i = 0; i != len; i++) {
				char c;
				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					expect_close = 1;
			}
		}
		txx9wdt_ping();
	}
	return len;
}

static int txx9wdt_ioctl(struct inode *inode, struct file *file,
	unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_timeout;
	static struct watchdog_info ident = {
		.options =		WDIOF_SETTIMEOUT |
					WDIOF_KEEPALIVEPING |
					WDIOF_MAGICCLOSE,
		.firmware_version =	0,
		.identity =		"Hardware Watchdog for TXx9",
	};

	switch (cmd) {
	default:
		return -ENOTTY;
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_KEEPALIVE:
		txx9wdt_ping();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_timeout, p))
			return -EFAULT;
		if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT)
			return -EINVAL;
		timeout = new_timeout;
		txx9wdt_stop();
		txx9wdt_start();
		/* Fall */
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, p);
	}
}

static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code,
	void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		txx9wdt_stop();
	return NOTIFY_DONE;
}

static const struct file_operations txx9wdt_fops = {
	.owner =	THIS_MODULE,
	.llseek =	no_llseek,
	.write =	txx9wdt_write,
	.ioctl =	txx9wdt_ioctl,
	.open =		txx9wdt_open,
	.release =	txx9wdt_release,
};

static struct miscdevice txx9wdt_miscdev = {
	.minor =	WATCHDOG_MINOR,
	.name =		"watchdog",
	.fops =		&txx9wdt_fops,
};

static struct notifier_block txx9wdt_notifier = {
	.notifier_call = txx9wdt_notify_sys
};

static int __init txx9wdt_probe(struct platform_device *dev)
{
	struct resource *res;
	int ret;

	txx9_imclk = clk_get(NULL, "imbus_clk");
	if (IS_ERR(txx9_imclk)) {
		ret = PTR_ERR(txx9_imclk);
		txx9_imclk = NULL;
		goto exit;
	}
	ret = clk_enable(txx9_imclk);
	if (ret) {
		clk_put(txx9_imclk);
		txx9_imclk = NULL;
		goto exit;
	}

	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
	if (!res)
		goto exit_busy;
	if (!devm_request_mem_region(&dev->dev,
				     res->start, res->end - res->start + 1,
				     "txx9wdt"))
		goto exit_busy;
	txx9wdt_reg = devm_ioremap(&dev->dev,
				   res->start, res->end - res->start + 1);
	if (!txx9wdt_reg)
		goto exit_busy;

	ret = register_reboot_notifier(&txx9wdt_notifier);
	if (ret)
		goto exit;

	ret = misc_register(&txx9wdt_miscdev);
	if (ret) {
		unregister_reboot_notifier(&txx9wdt_notifier);
		goto exit;
	}

	printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
	       "timeout=%d sec (max %ld) (nowayout= %d)\n",
	       timeout, WD_MAX_TIMEOUT, nowayout);

	return 0;
exit_busy:
	ret = -EBUSY;
exit:
	if (txx9_imclk) {
		clk_disable(txx9_imclk);
		clk_put(txx9_imclk);
	}
	return ret;
}

static int __exit txx9wdt_remove(struct platform_device *dev)
{
	misc_deregister(&txx9wdt_miscdev);
	unregister_reboot_notifier(&txx9wdt_notifier);
	clk_disable(txx9_imclk);
	clk_put(txx9_imclk);
	return 0;
}

static struct platform_driver txx9wdt_driver = {
	.remove = __exit_p(txx9wdt_remove),
	.driver = {
		.name = "txx9wdt",
		.owner = THIS_MODULE,
	},
};

static int __init watchdog_init(void)
{
	return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
}

static void __exit watchdog_exit(void)
{
	platform_driver_unregister(&txx9wdt_driver);
}

module_init(watchdog_init);
module_exit(watchdog_exit);

MODULE_DESCRIPTION("TXx9 Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:txx9wdt");
Commit	Line	Data
6f702fce AN	1	/*
	2	* txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
	3	*
	4	* Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	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/reboot.h>
	17	#include <linux/init.h>
	18	#include <linux/uaccess.h>
	19	#include <linux/platform_device.h>
	20	#include <linux/clk.h>
	21	#include <linux/err.h>
	22	#include <linux/io.h>
	23	#include <asm/txx9tmr.h>
	24
	25	#define TIMER_MARGIN 60 /* Default is 60 seconds */
	26
	27	static int timeout = TIMER_MARGIN; /* in seconds */
	28	module_param(timeout, int, 0);
	29	MODULE_PARM_DESC(timeout,
	30	"Watchdog timeout in seconds. "
	31	"(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
	32	"default=" __MODULE_STRING(TIMER_MARGIN) ")");
	33
	34	static int nowayout = WATCHDOG_NOWAYOUT;
	35	module_param(nowayout, int, 0);
	36	MODULE_PARM_DESC(nowayout,
	37	"Watchdog cannot be stopped once started "
	38	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	39
	40	#define WD_TIMER_CCD 7 /* 1/256 */
	41	#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
	42	#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
	43
	44	static unsigned long txx9wdt_alive;
	45	static int expect_close;
	46	static struct txx9_tmr_reg __iomem *txx9wdt_reg;
	47	static struct clk *txx9_imclk;
	48
	49	static void txx9wdt_ping(void)
	50	{
	51	__raw_writel(TXx9_TMWTMR_TWIE \| TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
	52	}
	53
	54	static void txx9wdt_start(void)
	55	{
	56	__raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
	57	__raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
	58	__raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
	59	__raw_writel(TXx9_TMTCR_TCE \| TXx9_TMTCR_CCDE \| TXx9_TMTCR_TMODE_WDOG,
	60	&txx9wdt_reg->tcr);
	61	__raw_writel(TXx9_TMWTMR_TWIE \| TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
	62	}
	63
	64	static void txx9wdt_stop(void)
65	{
66	__raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
67	__raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
68	&txx9wdt_reg->tcr);
69	}
70
71	static int txx9wdt_open(struct inode inode, struct file file)
72	{
73	if (test_and_set_bit(0, &txx9wdt_alive))
74	return -EBUSY;
75
76	if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
77	clear_bit(0, &txx9wdt_alive);
78	return -EBUSY;
79	}
80
81	if (nowayout)
82	__module_get(THIS_MODULE);
83
84	txx9wdt_start();
85	return nonseekable_open(inode, file);
86	}
87
88	static int txx9wdt_release(struct inode inode, struct file file)
89	{
90	if (expect_close)
91	txx9wdt_stop();
92	else {
93	printk(KERN_CRIT "txx9wdt: "
94	"Unexpected close, not stopping watchdog!\n");
95	txx9wdt_ping();
96	}
97	clear_bit(0, &txx9wdt_alive);
98	expect_close = 0;
99	return 0;
100	}
101
102	static ssize_t txx9wdt_write(struct file file, const char __user data,
103	size_t len, loff_t *ppos)
104	{
105	if (len) {
106	if (!nowayout) {
107	size_t i;
108
109	expect_close = 0;
110	for (i = 0; i != len; i++) {
111	char c;
112	if (get_user(c, data + i))
113	return -EFAULT;
114	if (c == 'V')
115	expect_close = 1;
116	}
117	}
118	txx9wdt_ping();
119	}
120	return len;
121	}
122
123	static int txx9wdt_ioctl(struct inode inode, struct file file,
124	unsigned int cmd, unsigned long arg)
125	{
126	void __user argp = (void __user )arg;
127	int __user *p = argp;
128	int new_timeout;
129	static struct watchdog_info ident = {
130	.options = WDIOF_SETTIMEOUT \|
131	WDIOF_KEEPALIVEPING \|
132	WDIOF_MAGICCLOSE,
133	.firmware_version = 0,
134	.identity = "Hardware Watchdog for TXx9",
135	};
136
137	switch (cmd) {
138	default:
139	return -ENOTTY;
140	case WDIOC_GETSUPPORT:
141	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
142	case WDIOC_GETSTATUS:
143	case WDIOC_GETBOOTSTATUS:
144	return put_user(0, p);
145	case WDIOC_KEEPALIVE:
146	txx9wdt_ping();
147	return 0;
148	case WDIOC_SETTIMEOUT:
149	if (get_user(new_timeout, p))
150	return -EFAULT;
151	if (new_timeout < 1 \|\| new_timeout > WD_MAX_TIMEOUT)
152	return -EINVAL;
153	timeout = new_timeout;
154	txx9wdt_stop();
155	txx9wdt_start();
156	/* Fall */
157	case WDIOC_GETTIMEOUT:
158	return put_user(timeout, p);
159	}
160	}
161
162	static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code,
163	void *unused)
164	{
165	if (code == SYS_DOWN \|\| code == SYS_HALT)
166	txx9wdt_stop();
167	return NOTIFY_DONE;
168	}
169
170	static const struct file_operations txx9wdt_fops = {
171	.owner = THIS_MODULE,
172	.llseek = no_llseek,
173	.write = txx9wdt_write,
174	.ioctl = txx9wdt_ioctl,
175	.open = txx9wdt_open,
176	.release = txx9wdt_release,
177	};
178
179	static struct miscdevice txx9wdt_miscdev = {
180	.minor = WATCHDOG_MINOR,
181	.name = "watchdog",
182	.fops = &txx9wdt_fops,
183	};
184
185	static struct notifier_block txx9wdt_notifier = {
186	.notifier_call = txx9wdt_notify_sys
187	};
188
189	static int __init txx9wdt_probe(struct platform_device *dev)
190	{
191	struct resource *res;
192	int ret;
193
194	txx9_imclk = clk_get(NULL, "imbus_clk");
195	if (IS_ERR(txx9_imclk)) {
196	ret = PTR_ERR(txx9_imclk);
197	txx9_imclk = NULL;
198	goto exit;
199	}
200	ret = clk_enable(txx9_imclk);
201	if (ret) {
202	clk_put(txx9_imclk);
203	txx9_imclk = NULL;
204	goto exit;
205	}
206
207	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
208	if (!res)
209	goto exit_busy;
210	if (!devm_request_mem_region(&dev->dev,
211	res->start, res->end - res->start + 1,
212	"txx9wdt"))
213	goto exit_busy;
214	txx9wdt_reg = devm_ioremap(&dev->dev,
215	res->start, res->end - res->start + 1);
216	if (!txx9wdt_reg)
217	goto exit_busy;
218
219	ret = register_reboot_notifier(&txx9wdt_notifier);
220	if (ret)
221	goto exit;
222
223	ret = misc_register(&txx9wdt_miscdev);
224	if (ret) {
225	unregister_reboot_notifier(&txx9wdt_notifier);
226	goto exit;
227	}
228
229	printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
230	"timeout=%d sec (max %ld) (nowayout= %d)\n",
231	timeout, WD_MAX_TIMEOUT, nowayout);
232
233	return 0;
234	exit_busy:
235	ret = -EBUSY;
236	exit:
237	if (txx9_imclk) {
238	clk_disable(txx9_imclk);
239	clk_put(txx9_imclk);
240	}
241	return ret;
242	}
243
244	static int __exit txx9wdt_remove(struct platform_device *dev)
245	{
246	misc_deregister(&txx9wdt_miscdev);
247	unregister_reboot_notifier(&txx9wdt_notifier);
248	clk_disable(txx9_imclk);
249	clk_put(txx9_imclk);
250	return 0;
251	}
252
253	static struct platform_driver txx9wdt_driver = {
254	.remove = __exit_p(txx9wdt_remove),
255	.driver = {
256	.name = "txx9wdt",
257	.owner = THIS_MODULE,
258	},
259	};
260
261	static int __init watchdog_init(void)
262	{
263	return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
264	}
265
266	static void __exit watchdog_exit(void)
267	{
268	platform_driver_unregister(&txx9wdt_driver);
269	}
270
271	module_init(watchdog_init);
272	module_exit(watchdog_exit);
273
274	MODULE_DESCRIPTION("TXx9 Watchdog Driver");
275	MODULE_LICENSE("GPL");
276	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
f37d193c	277	MODULE_ALIAS("platform:txx9wdt");