[mirror_ubuntu-jammy-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 <linux/io.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 stream_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,
	.compat_ioctl	= compat_ptr_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>
072cb8b6	32	#include <linux/io.h>
88cce427 PDM	33
88cce427 PDM	34	#include <asm/coldfire.h>
9b9c63ff PDM	35	#include <asm/m54xxsim.h>
9b9c63ff PDM	36	#include <asm/m54xxgpt.h>
88cce427	37
86a1e189	38	static bool nowayout = WATCHDOG_NOWAYOUT;
88cce427 PDM	39	static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */
	40	static unsigned long wdt_status;
	41
	42	#define WDT_IN_USE 0
	43	#define WDT_OK_TO_CLOSE 1
	44
	45	static void wdt_enable(void)
	46	{
	47	unsigned int gms0;
	48
	49	/* preserve GPIO usage, if any */
944c3d81	50	gms0 = __raw_readl(MCF_GPT_GMS0);
88cce427 PDM	51	if (gms0 & MCF_GPT_GMS_TMS_GPIO)
	52	gms0 &= (MCF_GPT_GMS_TMS_GPIO \| MCF_GPT_GMS_GPIO_MASK
	53	\| MCF_GPT_GMS_OD);
	54	else
	55	gms0 = MCF_GPT_GMS_TMS_GPIO \| MCF_GPT_GMS_OD;
944c3d81	56	__raw_writel(gms0, MCF_GPT_GMS0);
88cce427	57	__raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) \|
944c3d81	58	MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0);
88cce427	59	gms0 \|= MCF_GPT_GMS_OCPW(0xA5) \| MCF_GPT_GMS_WDEN \| MCF_GPT_GMS_CE;
944c3d81	60	__raw_writel(gms0, MCF_GPT_GMS0);
88cce427 PDM	61	}
	62
	63	static void wdt_disable(void)
	64	{
	65	unsigned int gms0;
	66
	67	/* disable watchdog */
944c3d81	68	gms0 = __raw_readl(MCF_GPT_GMS0);
88cce427	69	gms0 &= ~(MCF_GPT_GMS_WDEN \| MCF_GPT_GMS_CE);
944c3d81	70	__raw_writel(gms0, MCF_GPT_GMS0);
88cce427 PDM	71	}
	72
	73	static void wdt_keepalive(void)
	74	{
	75	unsigned int gms0;
	76
944c3d81	77	gms0 = __raw_readl(MCF_GPT_GMS0);
88cce427	78	gms0 \|= MCF_GPT_GMS_OCPW(0xA5);
944c3d81	79	__raw_writel(gms0, MCF_GPT_GMS0);
88cce427 PDM	80	}
88cce427 PDM	81
9b9c63ff	82	static int m54xx_wdt_open(struct inode inode, struct file file)
88cce427 PDM	83	{
	84	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	85	return -EBUSY;
	86
	87	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	88	wdt_enable();
c5bf68fe	89	return stream_open(inode, file);
88cce427 PDM	90	}
88cce427 PDM	91
9b9c63ff	92	static ssize_t m54xx_wdt_write(struct file file, const char data,
88cce427 PDM	93	size_t len, loff_t *ppos)
	94	{
	95	if (len) {
	96	if (!nowayout) {
	97	size_t i;
	98
	99	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	100
	101	for (i = 0; i != len; i++) {
	102	char c;
	103
	104	if (get_user(c, data + i))
	105	return -EFAULT;
	106	if (c == 'V')
	107	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	108	}
	109	}
	110	wdt_keepalive();
	111	}
	112	return len;
	113	}
	114
	115	static const struct watchdog_info ident = {
	116	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	117	WDIOF_KEEPALIVEPING,
9b9c63ff	118	.identity = "Coldfire M54xx Watchdog",
88cce427 PDM	119	};
88cce427 PDM	120
9b9c63ff	121	static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
88cce427 PDM	122	unsigned long arg)
	123	{
	124	int ret = -ENOTTY;
	125	int time;
	126
	127	switch (cmd) {
	128	case WDIOC_GETSUPPORT:
	129	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	130	sizeof(ident)) ? -EFAULT : 0;
	131	break;
	132
	133	case WDIOC_GETSTATUS:
	134	ret = put_user(0, (int *)arg);
	135	break;
	136
	137	case WDIOC_GETBOOTSTATUS:
	138	ret = put_user(0, (int *)arg);
	139	break;
	140
	141	case WDIOC_KEEPALIVE:
	142	wdt_keepalive();
	143	ret = 0;
	144	break;
	145
	146	case WDIOC_SETTIMEOUT:
	147	ret = get_user(time, (int *)arg);
	148	if (ret)
	149	break;
	150
	151	if (time <= 0 \|\| time > 30) {
	152	ret = -EINVAL;
	153	break;
	154	}
	155
	156	heartbeat = time;
	157	wdt_enable();
	158	/* Fall through */
	159
	160	case WDIOC_GETTIMEOUT:
	161	ret = put_user(heartbeat, (int *)arg);
	162	break;
	163	}
	164	return ret;
	165	}
	166
9b9c63ff	167	static int m54xx_wdt_release(struct inode inode, struct file file)
88cce427 PDM	168	{
	169	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
	170	wdt_disable();
	171	else {
27c766aa	172	pr_crit("Device closed unexpectedly - timer will not stop\n");
88cce427 PDM	173	wdt_keepalive();
	174	}
	175	clear_bit(WDT_IN_USE, &wdt_status);
	176	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	177
	178	return 0;
	179	}
	180
	181
9b9c63ff	182	static const struct file_operations m54xx_wdt_fops = {
88cce427 PDM	183	.owner = THIS_MODULE,
88cce427 PDM	184	.llseek = no_llseek,
9b9c63ff PDM	185	.write = m54xx_wdt_write,
9b9c63ff PDM	186	.unlocked_ioctl = m54xx_wdt_ioctl,
b6dfb247	187	.compat_ioctl = compat_ptr_ioctl,
9b9c63ff PDM	188	.open = m54xx_wdt_open,
9b9c63ff PDM	189	.release = m54xx_wdt_release,
88cce427 PDM	190	};
88cce427 PDM	191
9b9c63ff	192	static struct miscdevice m54xx_wdt_miscdev = {
88cce427 PDM	193	.minor = WATCHDOG_MINOR,
88cce427 PDM	194	.name = "watchdog",
9b9c63ff	195	.fops = &m54xx_wdt_fops,
88cce427 PDM	196	};
88cce427 PDM	197
9b9c63ff	198	static int __init m54xx_wdt_init(void)
88cce427	199	{
944c3d81	200	if (!request_mem_region(MCF_GPT_GCIR0, 4, "Coldfire M54xx Watchdog")) {
27c766aa	201	pr_warn("I/O region busy\n");
88cce427 PDM	202	return -EBUSY;
88cce427 PDM	203	}
27c766aa	204	pr_info("driver is loaded\n");
88cce427	205
9b9c63ff	206	return misc_register(&m54xx_wdt_miscdev);
88cce427 PDM	207	}
88cce427 PDM	208
9b9c63ff	209	static void __exit m54xx_wdt_exit(void)
88cce427	210	{
9b9c63ff	211	misc_deregister(&m54xx_wdt_miscdev);
944c3d81	212	release_mem_region(MCF_GPT_GCIR0, 4);
88cce427 PDM	213	}
88cce427 PDM	214
9b9c63ff PDM	215	module_init(m54xx_wdt_init);
9b9c63ff PDM	216	module_exit(m54xx_wdt_exit);
88cce427 PDM	217
88cce427 PDM	218	MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
9b9c63ff	219	MODULE_DESCRIPTION("Coldfire M54xx Watchdog");
88cce427 PDM	220
	221	module_param(heartbeat, int, 0);
	222	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");
	223
86a1e189	224	module_param(nowayout, bool, 0);
88cce427 PDM	225	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	226
	227	MODULE_LICENSE("GPL");