[linux.git] / drivers / watchdog / m54xx_wdt.c

/*
 * drivers/watchdog/m54xx_wdt.c
 *
 * Watchdog driver for ColdFire MCF547x & MCF548x processors
 * Copyright 2010 (c) Philippe De Muyter <[email protected]>
 *
 * Adapted from the IXP4xx watchdog driver, which carries these notices:
 *
 *  Author: Deepak Saxena <[email protected]>
 *
 *  Copyright 2004 (c) MontaVista, Software, Inc.
 *  Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <[email protected]>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>

#include <asm/coldfire.h>
#include <asm/m54xxsim.h>
#include <asm/m54xxgpt.h>

static int nowayout = WATCHDOG_NOWAYOUT;
static unsigned int heartbeat = 30;	/* (secs) Default is 0.5 minute */
static unsigned long wdt_status;

#define	WDT_IN_USE		0
#define	WDT_OK_TO_CLOSE		1

static void wdt_enable(void)
{
	unsigned int gms0;

	/* preserve GPIO usage, if any */
	gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
	if (gms0 & MCF_GPT_GMS_TMS_GPIO)
		gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK
							| MCF_GPT_GMS_OD);
	else
		gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD;
	__raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
	__raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) |
			MCF_GPT_GCIR_CNT(0xffff), MCF_MBAR + MCF_GPT_GCIR0);
	gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE;
	__raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
}

static void wdt_disable(void)
{
	unsigned int gms0;

	/* disable watchdog */
	gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
	gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE);
	__raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
}

static void wdt_keepalive(void)
{
	unsigned int gms0;

	gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
	gms0 |= MCF_GPT_GMS_OCPW(0xA5);
	__raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
}

static int m54xx_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
		return -EBUSY;

	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	wdt_enable();
	return nonseekable_open(inode, file);
}

static ssize_t m54xx_wdt_write(struct file *file, const char *data,
						size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

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

				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
			}
		}
		wdt_keepalive();
	}
	return len;
}

static const struct watchdog_info ident = {
	.options	= WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
				WDIOF_KEEPALIVEPING,
	.identity	= "Coldfire M54xx Watchdog",
};

static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
							 unsigned long arg)
{
	int ret = -ENOTTY;
	int time;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user((struct watchdog_info *)arg, &ident,
				   sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_KEEPALIVE:
		wdt_keepalive();
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(time, (int *)arg);
		if (ret)
			break;

		if (time <= 0 || time > 30) {
			ret = -EINVAL;
			break;
		}

		heartbeat = time;
		wdt_enable();
		/* Fall through */

	case WDIOC_GETTIMEOUT:
		ret = put_user(heartbeat, (int *)arg);
		break;
	}
	return ret;
}

static int m54xx_wdt_release(struct inode *inode, struct file *file)
{
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
		wdt_disable();
	else {
		printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
					"timer will not stop\n");
		wdt_keepalive();
	}
	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
}


static const struct file_operations m54xx_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= m54xx_wdt_write,
	.unlocked_ioctl	= m54xx_wdt_ioctl,
	.open		= m54xx_wdt_open,
	.release	= m54xx_wdt_release,
};

static struct miscdevice m54xx_wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &m54xx_wdt_fops,
};

static int __init m54xx_wdt_init(void)
{
	if (!request_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4,
						"Coldfire M54xx Watchdog")) {
		printk(KERN_WARNING
				"Coldfire M54xx Watchdog : I/O region busy\n");
		return -EBUSY;
	}
	printk(KERN_INFO "ColdFire watchdog driver is loaded.\n");

	return misc_register(&m54xx_wdt_miscdev);
}

static void __exit m54xx_wdt_exit(void)
{
	misc_deregister(&m54xx_wdt_miscdev);
	release_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4);
}

module_init(m54xx_wdt_init);
module_exit(m54xx_wdt_exit);

MODULE_AUTHOR("Philippe De Muyter <[email protected]>");
MODULE_DESCRIPTION("Coldfire M54xx Watchdog");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");

MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
88cce427	1	/*
9b9c63ff	2	* drivers/watchdog/m54xx_wdt.c
88cce427	3	*
9b9c63ff	4	* Watchdog driver for ColdFire MCF547x & MCF548x processors
88cce427 PDM	5	* Copyright 2010 (c) Philippe De Muyter <[email protected]>
	6	*
	7	* Adapted from the IXP4xx watchdog driver, which carries these notices:
	8	*
	9	* Author: Deepak Saxena <[email protected]>
	10	*
	11	* Copyright 2004 (c) MontaVista, Software, Inc.
	12	* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <[email protected]>
	13	*
	14	* This file is licensed under the terms of the GNU General Public
	15	* License version 2. This program is licensed "as is" without any
	16	* warranty of any kind, whether express or implied.
	17	*/
	18
	19	#include <linux/module.h>
	20	#include <linux/moduleparam.h>
	21	#include <linux/types.h>
	22	#include <linux/kernel.h>
	23	#include <linux/fs.h>
	24	#include <linux/miscdevice.h>
	25	#include <linux/watchdog.h>
	26	#include <linux/init.h>
	27	#include <linux/bitops.h>
	28	#include <linux/ioport.h>
	29	#include <linux/uaccess.h>
	30
	31	#include <asm/coldfire.h>
9b9c63ff PDM	32	#include <asm/m54xxsim.h>
9b9c63ff PDM	33	#include <asm/m54xxgpt.h>
88cce427 PDM	34
	35	static int nowayout = WATCHDOG_NOWAYOUT;
	36	static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */
	37	static unsigned long wdt_status;
	38
	39	#define WDT_IN_USE 0
	40	#define WDT_OK_TO_CLOSE 1
	41
	42	static void wdt_enable(void)
	43	{
	44	unsigned int gms0;
	45
	46	/* preserve GPIO usage, if any */
	47	gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
	48	if (gms0 & MCF_GPT_GMS_TMS_GPIO)
	49	gms0 &= (MCF_GPT_GMS_TMS_GPIO \| MCF_GPT_GMS_GPIO_MASK
	50	\| MCF_GPT_GMS_OD);
	51	else
	52	gms0 = MCF_GPT_GMS_TMS_GPIO \| MCF_GPT_GMS_OD;
	53	__raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
	54	__raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) \|
	55	MCF_GPT_GCIR_CNT(0xffff), MCF_MBAR + MCF_GPT_GCIR0);
	56	gms0 \|= MCF_GPT_GMS_OCPW(0xA5) \| MCF_GPT_GMS_WDEN \| MCF_GPT_GMS_CE;
	57	__raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
	58	}
	59
	60	static void wdt_disable(void)
	61	{
	62	unsigned int gms0;
	63
	64	/* disable watchdog */
	65	gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
	66	gms0 &= ~(MCF_GPT_GMS_WDEN \| MCF_GPT_GMS_CE);
	67	__raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
	68	}
	69
	70	static void wdt_keepalive(void)
	71	{
	72	unsigned int gms0;
	73
	74	gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
	75	gms0 \|= MCF_GPT_GMS_OCPW(0xA5);
	76	__raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
	77	}
	78
9b9c63ff	79	static int m54xx_wdt_open(struct inode inode, struct file file)
88cce427 PDM	80	{
	81	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	82	return -EBUSY;
	83
	84	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	85	wdt_enable();
	86	return nonseekable_open(inode, file);
	87	}
	88
9b9c63ff	89	static ssize_t m54xx_wdt_write(struct file file, const char data,
88cce427 PDM	90	size_t len, loff_t *ppos)
	91	{
	92	if (len) {
	93	if (!nowayout) {
	94	size_t i;
	95
	96	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	97
	98	for (i = 0; i != len; i++) {
	99	char c;
	100
	101	if (get_user(c, data + i))
	102	return -EFAULT;
	103	if (c == 'V')
	104	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	105	}
	106	}
	107	wdt_keepalive();
	108	}
	109	return len;
	110	}
	111
	112	static const struct watchdog_info ident = {
	113	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	114	WDIOF_KEEPALIVEPING,
9b9c63ff	115	.identity = "Coldfire M54xx Watchdog",
88cce427 PDM	116	};
88cce427 PDM	117
9b9c63ff	118	static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
88cce427 PDM	119	unsigned long arg)
	120	{
	121	int ret = -ENOTTY;
	122	int time;
	123
	124	switch (cmd) {
	125	case WDIOC_GETSUPPORT:
	126	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	127	sizeof(ident)) ? -EFAULT : 0;
	128	break;
	129
	130	case WDIOC_GETSTATUS:
	131	ret = put_user(0, (int *)arg);
	132	break;
	133
	134	case WDIOC_GETBOOTSTATUS:
	135	ret = put_user(0, (int *)arg);
	136	break;
	137
	138	case WDIOC_KEEPALIVE:
	139	wdt_keepalive();
	140	ret = 0;
	141	break;
	142
	143	case WDIOC_SETTIMEOUT:
	144	ret = get_user(time, (int *)arg);
	145	if (ret)
	146	break;
	147
	148	if (time <= 0 \|\| time > 30) {
	149	ret = -EINVAL;
	150	break;
	151	}
	152
	153	heartbeat = time;
	154	wdt_enable();
	155	/* Fall through */
	156
	157	case WDIOC_GETTIMEOUT:
	158	ret = put_user(heartbeat, (int *)arg);
	159	break;
	160	}
	161	return ret;
	162	}
	163
9b9c63ff	164	static int m54xx_wdt_release(struct inode inode, struct file file)
88cce427 PDM	165	{
	166	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
	167	wdt_disable();
	168	else {
	169	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
	170	"timer will not stop\n");
	171	wdt_keepalive();
	172	}
	173	clear_bit(WDT_IN_USE, &wdt_status);
	174	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	175
	176	return 0;
	177	}
	178
	179
9b9c63ff	180	static const struct file_operations m54xx_wdt_fops = {
88cce427 PDM	181	.owner = THIS_MODULE,
88cce427 PDM	182	.llseek = no_llseek,
9b9c63ff PDM	183	.write = m54xx_wdt_write,
	184	.unlocked_ioctl = m54xx_wdt_ioctl,
	185	.open = m54xx_wdt_open,
	186	.release = m54xx_wdt_release,
88cce427 PDM	187	};
88cce427 PDM	188
9b9c63ff	189	static struct miscdevice m54xx_wdt_miscdev = {
88cce427 PDM	190	.minor = WATCHDOG_MINOR,
88cce427 PDM	191	.name = "watchdog",
9b9c63ff	192	.fops = &m54xx_wdt_fops,
88cce427 PDM	193	};
88cce427 PDM	194
9b9c63ff	195	static int __init m54xx_wdt_init(void)
88cce427 PDM	196	{
88cce427 PDM	197	if (!request_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4,
9b9c63ff	198	"Coldfire M54xx Watchdog")) {
88cce427	199	printk(KERN_WARNING
9b9c63ff	200	"Coldfire M54xx Watchdog : I/O region busy\n");
88cce427 PDM	201	return -EBUSY;
	202	}
	203	printk(KERN_INFO "ColdFire watchdog driver is loaded.\n");
	204
9b9c63ff	205	return misc_register(&m54xx_wdt_miscdev);
88cce427 PDM	206	}
88cce427 PDM	207
9b9c63ff	208	static void __exit m54xx_wdt_exit(void)
88cce427	209	{
9b9c63ff	210	misc_deregister(&m54xx_wdt_miscdev);
88cce427 PDM	211	release_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4);
	212	}
	213
9b9c63ff PDM	214	module_init(m54xx_wdt_init);
9b9c63ff PDM	215	module_exit(m54xx_wdt_exit);
88cce427 PDM	216
88cce427 PDM	217	MODULE_AUTHOR("Philippe De Muyter <[email protected]>");
9b9c63ff	218	MODULE_DESCRIPTION("Coldfire M54xx Watchdog");
88cce427 PDM	219
	220	module_param(heartbeat, int, 0);
	221	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");
	222
	223	module_param(nowayout, int, 0);
	224	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	225
	226	MODULE_LICENSE("GPL");
	227	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);