[GitHub/mt8127/android_kernel_alcatel_ttab.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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 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 {
		pr_crit("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;
	}

	pr_info("Hardware Watchdog Timer: 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 <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	*/
27c766aa JP	10
	11	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	12
6f702fce AN	13	#include <linux/module.h>
	14	#include <linux/moduleparam.h>
	15	#include <linux/types.h>
	16	#include <linux/miscdevice.h>
	17	#include <linux/watchdog.h>
	18	#include <linux/fs.h>
6f702fce AN	19	#include <linux/init.h>
	20	#include <linux/uaccess.h>
	21	#include <linux/platform_device.h>
	22	#include <linux/clk.h>
	23	#include <linux/err.h>
	24	#include <linux/io.h>
	25	#include <asm/txx9tmr.h>
	26
	27	#define TIMER_MARGIN 60 /* Default is 60 seconds */
	28
	29	static int timeout = TIMER_MARGIN; /* in seconds */
	30	module_param(timeout, int, 0);
	31	MODULE_PARM_DESC(timeout,
	32	"Watchdog timeout in seconds. "
	33	"(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
	34	"default=" __MODULE_STRING(TIMER_MARGIN) ")");
	35
86a1e189 WVS	36	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	37	module_param(nowayout, bool, 0);
6f702fce AN	38	MODULE_PARM_DESC(nowayout,
	39	"Watchdog cannot be stopped once started "
	40	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	41
	42	#define WD_TIMER_CCD 7 /* 1/256 */
	43	#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
	44	#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
	45
	46	static unsigned long txx9wdt_alive;
	47	static int expect_close;
	48	static struct txx9_tmr_reg __iomem *txx9wdt_reg;
	49	static struct clk *txx9_imclk;
f8494e06	50	static DEFINE_SPINLOCK(txx9_lock);
6f702fce AN	51
	52	static void txx9wdt_ping(void)
	53	{
8dc244f7	54	spin_lock(&txx9_lock);
6f702fce	55	__raw_writel(TXx9_TMWTMR_TWIE \| TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
8dc244f7	56	spin_unlock(&txx9_lock);
6f702fce AN	57	}
	58
	59	static void txx9wdt_start(void)
	60	{
8dc244f7	61	spin_lock(&txx9_lock);
6f702fce AN	62	__raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
	63	__raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
	64	__raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
	65	__raw_writel(TXx9_TMTCR_TCE \| TXx9_TMTCR_CCDE \| TXx9_TMTCR_TMODE_WDOG,
	66	&txx9wdt_reg->tcr);
	67	__raw_writel(TXx9_TMWTMR_TWIE \| TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
8dc244f7	68	spin_unlock(&txx9_lock);
6f702fce AN	69	}
	70
	71	static void txx9wdt_stop(void)
	72	{
8dc244f7	73	spin_lock(&txx9_lock);
6f702fce AN	74	__raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
	75	__raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
	76	&txx9wdt_reg->tcr);
8dc244f7	77	spin_unlock(&txx9_lock);
6f702fce AN	78	}
	79
	80	static int txx9wdt_open(struct inode inode, struct file file)
	81	{
	82	if (test_and_set_bit(0, &txx9wdt_alive))
	83	return -EBUSY;
	84
	85	if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
	86	clear_bit(0, &txx9wdt_alive);
	87	return -EBUSY;
	88	}
	89
	90	if (nowayout)
	91	__module_get(THIS_MODULE);
	92
	93	txx9wdt_start();
	94	return nonseekable_open(inode, file);
	95	}
	96
	97	static int txx9wdt_release(struct inode inode, struct file file)
	98	{
	99	if (expect_close)
	100	txx9wdt_stop();
	101	else {
27c766aa	102	pr_crit("Unexpected close, not stopping watchdog!\n");
6f702fce AN	103	txx9wdt_ping();
	104	}
	105	clear_bit(0, &txx9wdt_alive);
	106	expect_close = 0;
	107	return 0;
	108	}
	109
	110	static ssize_t txx9wdt_write(struct file file, const char __user data,
	111	size_t len, loff_t *ppos)
	112	{
	113	if (len) {
	114	if (!nowayout) {
	115	size_t i;
	116
	117	expect_close = 0;
	118	for (i = 0; i != len; i++) {
	119	char c;
	120	if (get_user(c, data + i))
	121	return -EFAULT;
	122	if (c == 'V')
	123	expect_close = 1;
	124	}
	125	}
	126	txx9wdt_ping();
	127	}
	128	return len;
	129	}
	130
8dc244f7 AC	131	static long txx9wdt_ioctl(struct file *file, unsigned int cmd,
8dc244f7 AC	132	unsigned long arg)
6f702fce AN	133	{
	134	void __user argp = (void __user )arg;
	135	int __user *p = argp;
	136	int new_timeout;
8dc244f7	137	static const struct watchdog_info ident = {
6f702fce AN	138	.options = WDIOF_SETTIMEOUT \|
	139	WDIOF_KEEPALIVEPING \|
	140	WDIOF_MAGICCLOSE,
	141	.firmware_version = 0,
	142	.identity = "Hardware Watchdog for TXx9",
	143	};
	144
	145	switch (cmd) {
6f702fce AN	146	case WDIOC_GETSUPPORT:
	147	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	148	case WDIOC_GETSTATUS:
	149	case WDIOC_GETBOOTSTATUS:
	150	return put_user(0, p);
	151	case WDIOC_KEEPALIVE:
	152	txx9wdt_ping();
	153	return 0;
	154	case WDIOC_SETTIMEOUT:
	155	if (get_user(new_timeout, p))
	156	return -EFAULT;
	157	if (new_timeout < 1 \|\| new_timeout > WD_MAX_TIMEOUT)
	158	return -EINVAL;
	159	timeout = new_timeout;
	160	txx9wdt_stop();
	161	txx9wdt_start();
	162	/* Fall */
	163	case WDIOC_GETTIMEOUT:
	164	return put_user(timeout, p);
0c06090c WVS	165	default:
0c06090c WVS	166	return -ENOTTY;
6f702fce AN	167	}
	168	}
	169
6f702fce	170	static const struct file_operations txx9wdt_fops = {
8dc244f7 AC	171	.owner = THIS_MODULE,
	172	.llseek = no_llseek,
	173	.write = txx9wdt_write,
	174	.unlocked_ioctl = txx9wdt_ioctl,
	175	.open = txx9wdt_open,
	176	.release = txx9wdt_release,
6f702fce AN	177	};
	178
	179	static struct miscdevice txx9wdt_miscdev = {
8dc244f7 AC	180	.minor = WATCHDOG_MINOR,
	181	.name = "watchdog",
	182	.fops = &txx9wdt_fops,
6f702fce AN	183	};
6f702fce AN	184
6f702fce AN	185	static int __init txx9wdt_probe(struct platform_device *dev)
	186	{
	187	struct resource *res;
	188	int ret;
	189
	190	txx9_imclk = clk_get(NULL, "imbus_clk");
	191	if (IS_ERR(txx9_imclk)) {
	192	ret = PTR_ERR(txx9_imclk);
	193	txx9_imclk = NULL;
	194	goto exit;
	195	}
	196	ret = clk_enable(txx9_imclk);
	197	if (ret) {
	198	clk_put(txx9_imclk);
	199	txx9_imclk = NULL;
	200	goto exit;
	201	}
	202
	203	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
	204	if (!res)
	205	goto exit_busy;
b782a563	206	if (!devm_request_mem_region(&dev->dev, res->start, resource_size(res),
6f702fce AN	207	"txx9wdt"))
6f702fce AN	208	goto exit_busy;
b782a563	209	txx9wdt_reg = devm_ioremap(&dev->dev, res->start, resource_size(res));
6f702fce AN	210	if (!txx9wdt_reg)
	211	goto exit_busy;
	212
6f702fce AN	213	ret = misc_register(&txx9wdt_miscdev);
6f702fce AN	214	if (ret) {
6f702fce AN	215	goto exit;
	216	}
	217
27c766aa JP	218	pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n",
27c766aa JP	219	timeout, WD_MAX_TIMEOUT, nowayout);
6f702fce AN	220
	221	return 0;
	222	exit_busy:
	223	ret = -EBUSY;
	224	exit:
	225	if (txx9_imclk) {
	226	clk_disable(txx9_imclk);
	227	clk_put(txx9_imclk);
	228	}
	229	return ret;
	230	}
	231
	232	static int __exit txx9wdt_remove(struct platform_device *dev)
	233	{
	234	misc_deregister(&txx9wdt_miscdev);
6f702fce AN	235	clk_disable(txx9_imclk);
	236	clk_put(txx9_imclk);
	237	return 0;
	238	}
	239
168b5251 WVS	240	static void txx9wdt_shutdown(struct platform_device *dev)
	241	{
	242	txx9wdt_stop();
	243	}
	244
6f702fce AN	245	static struct platform_driver txx9wdt_driver = {
6f702fce AN	246	.remove = __exit_p(txx9wdt_remove),
168b5251	247	.shutdown = txx9wdt_shutdown,
6f702fce AN	248	.driver = {
	249	.name = "txx9wdt",
	250	.owner = THIS_MODULE,
	251	},
	252	};
	253
	254	static int __init watchdog_init(void)
	255	{
	256	return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
	257	}
	258
	259	static void __exit watchdog_exit(void)
	260	{
	261	platform_driver_unregister(&txx9wdt_driver);
	262	}
	263
	264	module_init(watchdog_init);
	265	module_exit(watchdog_exit);
	266
	267	MODULE_DESCRIPTION("TXx9 Watchdog Driver");
	268	MODULE_LICENSE("GPL");
	269	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
f37d193c	270	MODULE_ALIAS("platform:txx9wdt");