[mirror_ubuntu-zesty-kernel.git] / drivers / watchdog / m54xx_wdt.c

/*
 * drivers/watchdog/m54xx_wdt.c
 *
 * Watchdog driver for ColdFire MCF547x & MCF548x processors
 * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be>
 *
 * Adapted from the IXP4xx watchdog driver, which carries these notices:
 *
 *  Author: Deepak Saxena <dsaxena@plexity.net>
 *
 *  Copyright 2004 (c) MontaVista, Software, Inc.
 *  Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 bool 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_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_GPT_GMS0);
	__raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) |
			MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0);
	gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE;
	__raw_writel(gms0, MCF_GPT_GMS0);
}

static void wdt_disable(void)
{
	unsigned int gms0;

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

static void wdt_keepalive(void)
{
	unsigned int gms0;

	gms0 = __raw_readl(MCF_GPT_GMS0);
	gms0 |= MCF_GPT_GMS_OCPW(0xA5);
	__raw_writel(gms0, 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 {
		pr_crit("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_GPT_GCIR0, 4, "Coldfire M54xx Watchdog")) {
		pr_warn("I/O region busy\n");
		return -EBUSY;
	}
	pr_info("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_GPT_GCIR0, 4);
}

module_init(m54xx_wdt_init);
module_exit(m54xx_wdt_exit);

MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
MODULE_DESCRIPTION("Coldfire M54xx Watchdog");

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

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

MODULE_LICENSE("GPL");
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 <phdm@macqel.be>
	6	*
	7	* Adapted from the IXP4xx watchdog driver, which carries these notices:
	8	*
	9	* Author: Deepak Saxena <dsaxena@plexity.net>
	10	*
	11	* Copyright 2004 (c) MontaVista, Software, Inc.
	12	* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
	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
27c766aa JP	19	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	20
88cce427 PDM	21	#include <linux/module.h>
	22	#include <linux/moduleparam.h>
	23	#include <linux/types.h>
	24	#include <linux/kernel.h>
	25	#include <linux/fs.h>
	26	#include <linux/miscdevice.h>
	27	#include <linux/watchdog.h>
	28	#include <linux/init.h>
	29	#include <linux/bitops.h>
	30	#include <linux/ioport.h>
	31	#include <linux/uaccess.h>
	32
	33	#include <asm/coldfire.h>
9b9c63ff PDM	34	#include <asm/m54xxsim.h>
9b9c63ff PDM	35	#include <asm/m54xxgpt.h>
88cce427	36
86a1e189	37	static bool nowayout = WATCHDOG_NOWAYOUT;
88cce427 PDM	38	static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */
	39	static unsigned long wdt_status;
	40
	41	#define WDT_IN_USE 0
	42	#define WDT_OK_TO_CLOSE 1
	43
	44	static void wdt_enable(void)
	45	{
	46	unsigned int gms0;
	47
	48	/* preserve GPIO usage, if any */
944c3d81	49	gms0 = __raw_readl(MCF_GPT_GMS0);
88cce427 PDM	50	if (gms0 & MCF_GPT_GMS_TMS_GPIO)
	51	gms0 &= (MCF_GPT_GMS_TMS_GPIO \| MCF_GPT_GMS_GPIO_MASK
	52	\| MCF_GPT_GMS_OD);
	53	else
	54	gms0 = MCF_GPT_GMS_TMS_GPIO \| MCF_GPT_GMS_OD;
944c3d81	55	__raw_writel(gms0, MCF_GPT_GMS0);
88cce427	56	__raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) \|
944c3d81	57	MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0);
88cce427	58	gms0 \|= MCF_GPT_GMS_OCPW(0xA5) \| MCF_GPT_GMS_WDEN \| MCF_GPT_GMS_CE;
944c3d81	59	__raw_writel(gms0, MCF_GPT_GMS0);
88cce427 PDM	60	}
	61
	62	static void wdt_disable(void)
	63	{
	64	unsigned int gms0;
	65
	66	/* disable watchdog */
944c3d81	67	gms0 = __raw_readl(MCF_GPT_GMS0);
88cce427	68	gms0 &= ~(MCF_GPT_GMS_WDEN \| MCF_GPT_GMS_CE);
944c3d81	69	__raw_writel(gms0, MCF_GPT_GMS0);
88cce427 PDM	70	}
	71
	72	static void wdt_keepalive(void)
	73	{
	74	unsigned int gms0;
	75
944c3d81	76	gms0 = __raw_readl(MCF_GPT_GMS0);
88cce427	77	gms0 \|= MCF_GPT_GMS_OCPW(0xA5);
944c3d81	78	__raw_writel(gms0, MCF_GPT_GMS0);
88cce427 PDM	79	}
88cce427 PDM	80
9b9c63ff	81	static int m54xx_wdt_open(struct inode inode, struct file file)
88cce427 PDM	82	{
	83	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	84	return -EBUSY;
	85
	86	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	87	wdt_enable();
	88	return nonseekable_open(inode, file);
	89	}
	90
9b9c63ff	91	static ssize_t m54xx_wdt_write(struct file file, const char data,
88cce427 PDM	92	size_t len, loff_t *ppos)
	93	{
	94	if (len) {
	95	if (!nowayout) {
	96	size_t i;
	97
	98	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	99
	100	for (i = 0; i != len; i++) {
	101	char c;
	102
	103	if (get_user(c, data + i))
	104	return -EFAULT;
	105	if (c == 'V')
	106	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	107	}
	108	}
	109	wdt_keepalive();
	110	}
	111	return len;
	112	}
	113
	114	static const struct watchdog_info ident = {
	115	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	116	WDIOF_KEEPALIVEPING,
9b9c63ff	117	.identity = "Coldfire M54xx Watchdog",
88cce427 PDM	118	};
88cce427 PDM	119
9b9c63ff	120	static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
88cce427 PDM	121	unsigned long arg)
	122	{
	123	int ret = -ENOTTY;
	124	int time;
	125
	126	switch (cmd) {
	127	case WDIOC_GETSUPPORT:
	128	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	129	sizeof(ident)) ? -EFAULT : 0;
	130	break;
	131
	132	case WDIOC_GETSTATUS:
	133	ret = put_user(0, (int *)arg);
	134	break;
	135
	136	case WDIOC_GETBOOTSTATUS:
	137	ret = put_user(0, (int *)arg);
	138	break;
	139
	140	case WDIOC_KEEPALIVE:
	141	wdt_keepalive();
	142	ret = 0;
	143	break;
	144
	145	case WDIOC_SETTIMEOUT:
	146	ret = get_user(time, (int *)arg);
	147	if (ret)
	148	break;
	149
	150	if (time <= 0 \|\| time > 30) {
	151	ret = -EINVAL;
	152	break;
	153	}
	154
	155	heartbeat = time;
	156	wdt_enable();
	157	/* Fall through */
	158
	159	case WDIOC_GETTIMEOUT:
	160	ret = put_user(heartbeat, (int *)arg);
	161	break;
	162	}
	163	return ret;
	164	}
	165
9b9c63ff	166	static int m54xx_wdt_release(struct inode inode, struct file file)
88cce427 PDM	167	{
	168	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
	169	wdt_disable();
	170	else {
27c766aa	171	pr_crit("Device closed unexpectedly - timer will not stop\n");
88cce427 PDM	172	wdt_keepalive();
	173	}
	174	clear_bit(WDT_IN_USE, &wdt_status);
	175	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	176
	177	return 0;
	178	}
	179
	180
9b9c63ff	181	static const struct file_operations m54xx_wdt_fops = {
88cce427 PDM	182	.owner = THIS_MODULE,
88cce427 PDM	183	.llseek = no_llseek,
9b9c63ff PDM	184	.write = m54xx_wdt_write,
	185	.unlocked_ioctl = m54xx_wdt_ioctl,
	186	.open = m54xx_wdt_open,
	187	.release = m54xx_wdt_release,
88cce427 PDM	188	};
88cce427 PDM	189
9b9c63ff	190	static struct miscdevice m54xx_wdt_miscdev = {
88cce427 PDM	191	.minor = WATCHDOG_MINOR,
88cce427 PDM	192	.name = "watchdog",
9b9c63ff	193	.fops = &m54xx_wdt_fops,
88cce427 PDM	194	};
88cce427 PDM	195
9b9c63ff	196	static int __init m54xx_wdt_init(void)
88cce427	197	{
944c3d81	198	if (!request_mem_region(MCF_GPT_GCIR0, 4, "Coldfire M54xx Watchdog")) {
27c766aa	199	pr_warn("I/O region busy\n");
88cce427 PDM	200	return -EBUSY;
88cce427 PDM	201	}
27c766aa	202	pr_info("driver is loaded\n");
88cce427	203
9b9c63ff	204	return misc_register(&m54xx_wdt_miscdev);
88cce427 PDM	205	}
88cce427 PDM	206
9b9c63ff	207	static void __exit m54xx_wdt_exit(void)
88cce427	208	{
9b9c63ff	209	misc_deregister(&m54xx_wdt_miscdev);
944c3d81	210	release_mem_region(MCF_GPT_GCIR0, 4);
88cce427 PDM	211	}
88cce427 PDM	212
9b9c63ff PDM	213	module_init(m54xx_wdt_init);
9b9c63ff PDM	214	module_exit(m54xx_wdt_exit);
88cce427 PDM	215
88cce427 PDM	216	MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
9b9c63ff	217	MODULE_DESCRIPTION("Coldfire M54xx Watchdog");
88cce427 PDM	218
	219	module_param(heartbeat, int, 0);
	220	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");
	221
86a1e189	222	module_param(nowayout, bool, 0);
88cce427 PDM	223	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	224
	225	MODULE_LICENSE("GPL");