[linux.git] / drivers / watchdog / txx9wdt.c

/*
 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
 *
 * Copyright (C) 2007 Atsushi Nemoto <[email protected]>
 *
 * 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/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 DEFINE_SPINLOCK(txx9_lock);

static void txx9wdt_ping(void)
{
	spin_lock(&txx9_lock);
	__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
	spin_unlock(&txx9_lock);
}

static void txx9wdt_start(void)
{
	spin_lock(&txx9_lock);
	__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);
	spin_unlock(&txx9_lock);
}

static void txx9wdt_stop(void)
{
	spin_lock(&txx9_lock);
	__raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
	__raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
		     &txx9wdt_reg->tcr);
	spin_unlock(&txx9_lock);
}

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

	switch (cmd) {
	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);
	default:
		return -ENOTTY;
	}
}

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

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

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, resource_size(res),
				     "txx9wdt"))
		goto exit_busy;
	txx9wdt_reg = devm_ioremap(&dev->dev, res->start, resource_size(res));
	if (!txx9wdt_reg)
		goto exit_busy;

	ret = misc_register(&txx9wdt_miscdev);
	if (ret) {
		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);
	clk_disable(txx9_imclk);
	clk_put(txx9_imclk);
	return 0;
}

static void txx9wdt_shutdown(struct platform_device *dev)
{
	txx9wdt_stop();
}

static struct platform_driver txx9wdt_driver = {
	.remove = __exit_p(txx9wdt_remove),
	.shutdown = txx9wdt_shutdown,
	.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 <[email protected]>
	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>
6f702fce AN	16	#include <linux/init.h>
	17	#include <linux/uaccess.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/clk.h>
	20	#include <linux/err.h>
	21	#include <linux/io.h>
	22	#include <asm/txx9tmr.h>
	23
	24	#define TIMER_MARGIN 60 /* Default is 60 seconds */
	25
	26	static int timeout = TIMER_MARGIN; /* in seconds */
	27	module_param(timeout, int, 0);
	28	MODULE_PARM_DESC(timeout,
	29	"Watchdog timeout in seconds. "
	30	"(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
	31	"default=" __MODULE_STRING(TIMER_MARGIN) ")");
	32
	33	static int nowayout = WATCHDOG_NOWAYOUT;
	34	module_param(nowayout, int, 0);
	35	MODULE_PARM_DESC(nowayout,
	36	"Watchdog cannot be stopped once started "
	37	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	38
	39	#define WD_TIMER_CCD 7 /* 1/256 */
	40	#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
	41	#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
	42
	43	static unsigned long txx9wdt_alive;
	44	static int expect_close;
	45	static struct txx9_tmr_reg __iomem *txx9wdt_reg;
	46	static struct clk *txx9_imclk;
f8494e06	47	static DEFINE_SPINLOCK(txx9_lock);
6f702fce AN	48
	49	static void txx9wdt_ping(void)
	50	{
8dc244f7	51	spin_lock(&txx9_lock);
6f702fce	52	__raw_writel(TXx9_TMWTMR_TWIE \| TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
8dc244f7	53	spin_unlock(&txx9_lock);
6f702fce AN	54	}
	55
	56	static void txx9wdt_start(void)
	57	{
8dc244f7	58	spin_lock(&txx9_lock);
6f702fce AN	59	__raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
	60	__raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
	61	__raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
	62	__raw_writel(TXx9_TMTCR_TCE \| TXx9_TMTCR_CCDE \| TXx9_TMTCR_TMODE_WDOG,
	63	&txx9wdt_reg->tcr);
	64	__raw_writel(TXx9_TMWTMR_TWIE \| TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
8dc244f7	65	spin_unlock(&txx9_lock);
6f702fce AN	66	}
	67
	68	static void txx9wdt_stop(void)
	69	{
8dc244f7	70	spin_lock(&txx9_lock);
6f702fce AN	71	__raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
	72	__raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
	73	&txx9wdt_reg->tcr);
8dc244f7	74	spin_unlock(&txx9_lock);
6f702fce AN	75	}
	76
	77	static int txx9wdt_open(struct inode inode, struct file file)
	78	{
	79	if (test_and_set_bit(0, &txx9wdt_alive))
	80	return -EBUSY;
	81
	82	if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
	83	clear_bit(0, &txx9wdt_alive);
	84	return -EBUSY;
	85	}
	86
	87	if (nowayout)
	88	__module_get(THIS_MODULE);
	89
	90	txx9wdt_start();
	91	return nonseekable_open(inode, file);
	92	}
	93
	94	static int txx9wdt_release(struct inode inode, struct file file)
	95	{
	96	if (expect_close)
	97	txx9wdt_stop();
	98	else {
	99	printk(KERN_CRIT "txx9wdt: "
	100	"Unexpected close, not stopping watchdog!\n");
	101	txx9wdt_ping();
	102	}
	103	clear_bit(0, &txx9wdt_alive);
	104	expect_close = 0;
	105	return 0;
	106	}
	107
	108	static ssize_t txx9wdt_write(struct file file, const char __user data,
	109	size_t len, loff_t *ppos)
	110	{
	111	if (len) {
	112	if (!nowayout) {
	113	size_t i;
	114
	115	expect_close = 0;
	116	for (i = 0; i != len; i++) {
	117	char c;
	118	if (get_user(c, data + i))
	119	return -EFAULT;
	120	if (c == 'V')
	121	expect_close = 1;
	122	}
	123	}
	124	txx9wdt_ping();
	125	}
	126	return len;
	127	}
	128
8dc244f7 AC	129	static long txx9wdt_ioctl(struct file *file, unsigned int cmd,
8dc244f7 AC	130	unsigned long arg)
6f702fce AN	131	{
	132	void __user argp = (void __user )arg;
	133	int __user *p = argp;
	134	int new_timeout;
8dc244f7	135	static const struct watchdog_info ident = {
6f702fce AN	136	.options = WDIOF_SETTIMEOUT \|
	137	WDIOF_KEEPALIVEPING \|
	138	WDIOF_MAGICCLOSE,
	139	.firmware_version = 0,
	140	.identity = "Hardware Watchdog for TXx9",
	141	};
	142
	143	switch (cmd) {
6f702fce AN	144	case WDIOC_GETSUPPORT:
	145	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	146	case WDIOC_GETSTATUS:
	147	case WDIOC_GETBOOTSTATUS:
	148	return put_user(0, p);
	149	case WDIOC_KEEPALIVE:
	150	txx9wdt_ping();
	151	return 0;
	152	case WDIOC_SETTIMEOUT:
	153	if (get_user(new_timeout, p))
	154	return -EFAULT;
	155	if (new_timeout < 1 \|\| new_timeout > WD_MAX_TIMEOUT)
	156	return -EINVAL;
	157	timeout = new_timeout;
	158	txx9wdt_stop();
	159	txx9wdt_start();
	160	/* Fall */
	161	case WDIOC_GETTIMEOUT:
	162	return put_user(timeout, p);
0c06090c WVS	163	default:
0c06090c WVS	164	return -ENOTTY;
6f702fce AN	165	}
	166	}
	167
6f702fce	168	static const struct file_operations txx9wdt_fops = {
8dc244f7 AC	169	.owner = THIS_MODULE,
	170	.llseek = no_llseek,
	171	.write = txx9wdt_write,
	172	.unlocked_ioctl = txx9wdt_ioctl,
	173	.open = txx9wdt_open,
	174	.release = txx9wdt_release,
6f702fce AN	175	};
	176
	177	static struct miscdevice txx9wdt_miscdev = {
8dc244f7 AC	178	.minor = WATCHDOG_MINOR,
	179	.name = "watchdog",
	180	.fops = &txx9wdt_fops,
6f702fce AN	181	};
6f702fce AN	182
6f702fce AN	183	static int __init txx9wdt_probe(struct platform_device *dev)
	184	{
	185	struct resource *res;
	186	int ret;
	187
	188	txx9_imclk = clk_get(NULL, "imbus_clk");
	189	if (IS_ERR(txx9_imclk)) {
	190	ret = PTR_ERR(txx9_imclk);
	191	txx9_imclk = NULL;
	192	goto exit;
	193	}
	194	ret = clk_enable(txx9_imclk);
	195	if (ret) {
	196	clk_put(txx9_imclk);
	197	txx9_imclk = NULL;
	198	goto exit;
	199	}
	200
	201	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
	202	if (!res)
	203	goto exit_busy;
b782a563	204	if (!devm_request_mem_region(&dev->dev, res->start, resource_size(res),
6f702fce AN	205	"txx9wdt"))
6f702fce AN	206	goto exit_busy;
b782a563	207	txx9wdt_reg = devm_ioremap(&dev->dev, res->start, resource_size(res));
6f702fce AN	208	if (!txx9wdt_reg)
	209	goto exit_busy;
	210
6f702fce AN	211	ret = misc_register(&txx9wdt_miscdev);
6f702fce AN	212	if (ret) {
6f702fce AN	213	goto exit;
	214	}
	215
	216	printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
	217	"timeout=%d sec (max %ld) (nowayout= %d)\n",
	218	timeout, WD_MAX_TIMEOUT, nowayout);
	219
	220	return 0;
	221	exit_busy:
	222	ret = -EBUSY;
	223	exit:
	224	if (txx9_imclk) {
	225	clk_disable(txx9_imclk);
	226	clk_put(txx9_imclk);
	227	}
	228	return ret;
	229	}
	230
	231	static int __exit txx9wdt_remove(struct platform_device *dev)
	232	{
	233	misc_deregister(&txx9wdt_miscdev);
6f702fce AN	234	clk_disable(txx9_imclk);
	235	clk_put(txx9_imclk);
	236	return 0;
	237	}
	238
168b5251 WVS	239	static void txx9wdt_shutdown(struct platform_device *dev)
	240	{
	241	txx9wdt_stop();
	242	}
	243
6f702fce AN	244	static struct platform_driver txx9wdt_driver = {
6f702fce AN	245	.remove = __exit_p(txx9wdt_remove),
168b5251	246	.shutdown = txx9wdt_shutdown,
6f702fce AN	247	.driver = {
	248	.name = "txx9wdt",
	249	.owner = THIS_MODULE,
	250	},
	251	};
	252
	253	static int __init watchdog_init(void)
	254	{
	255	return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
	256	}
	257
	258	static void __exit watchdog_exit(void)
	259	{
	260	platform_driver_unregister(&txx9wdt_driver);
	261	}
	262
	263	module_init(watchdog_init);
	264	module_exit(watchdog_exit);
	265
	266	MODULE_DESCRIPTION("TXx9 Watchdog Driver");
	267	MODULE_LICENSE("GPL");
	268	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
f37d193c	269	MODULE_ALIAS("platform:txx9wdt");