[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / char / watchdog / at32ap700x_wdt.c

/*
 * Watchdog driver for Atmel AT32AP700X devices
 *
 * Copyright (C) 2005-2006 Atmel Corporation
 *
 * 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/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/io.h>

#define TIMEOUT_MIN		1
#define TIMEOUT_DEFAULT		CONFIG_AT32AP700X_WDT_TIMEOUT
#define TIMEOUT_MAX		2

/* Watchdog registers and write/read macro */
#define WDT_CTRL		0x00
#define WDT_CTRL_EN		   0
#define WDT_CTRL_PSEL		   8
#define WDT_CTRL_KEY		  24

#define WDT_CLR			0x04

#define WDT_BIT(name)		(1 << WDT_##name)
#define WDT_BF(name,value)	((value) << WDT_##name)

#define wdt_readl(dev,reg)				\
	__raw_readl((dev)->regs + WDT_##reg)
#define wdt_writel(dev,reg,value)			\
	__raw_writel((value), (dev)->regs + WDT_##reg)

struct wdt_at32ap700x {
	void __iomem		*regs;
	int			timeout;
	int			users;
	struct miscdevice	miscdev;
};

static struct wdt_at32ap700x *wdt;

/*
 * Disable the watchdog.
 */
static void inline at32_wdt_stop(void)
{
	unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
	wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
	wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
}

/*
 * Enable and reset the watchdog.
 */
static void inline at32_wdt_start(void)
{
	/* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
	unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;

	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
			| WDT_BF(CTRL_PSEL, psel)
			| WDT_BF(CTRL_KEY, 0x55));
	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
			| WDT_BF(CTRL_PSEL, psel)
			| WDT_BF(CTRL_KEY, 0xaa));
}

/*
 * Pat the watchdog timer.
 */
static void inline at32_wdt_pat(void)
{
	wdt_writel(wdt, CLR, 0x42);
}

/*
 * Watchdog device is opened, and watchdog starts running.
 */
static int at32_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(1, &wdt->users))
		return -EBUSY;

	at32_wdt_start();
	return nonseekable_open(inode, file);
}

/*
 * Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then
 * the watchdog is also disabled.
 */
static int at32_wdt_close(struct inode *inode, struct file *file)
{
#ifndef CONFIG_WATCHDOG_NOWAYOUT
	at32_wdt_stop();
#endif
	clear_bit(1, &wdt->users);
	return 0;
}

/*
 * Change the watchdog time interval.
 */
static int at32_wdt_settimeout(int time)
{
	/*
	 * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
	 * 2 ^ 16 allowing up to 2 seconds timeout.
	 */
	if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
		return -EINVAL;

	/*
	 * Set new watchdog time. It will be used when at32_wdt_start() is
	 * called.
	 */
	wdt->timeout = time;
	return 0;
}

static struct watchdog_info at32_wdt_info = {
	.identity	= "at32ap700x watchdog",
	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
};

/*
 * Handle commands from user-space.
 */
static int at32_wdt_ioctl(struct inode *inode, struct file *file,
		unsigned int cmd, unsigned long arg)
{
	int ret = -ENOTTY;
	int time;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;

	switch (cmd) {
	case WDIOC_KEEPALIVE:
		at32_wdt_pat();
		ret = 0;
		break;
	case WDIOC_GETSUPPORT:
		ret = copy_to_user(argp, &at32_wdt_info,
				sizeof(at32_wdt_info)) ? -EFAULT : 0;
		break;
	case WDIOC_SETTIMEOUT:
		ret = get_user(time, p);
		if (ret)
			break;
		ret = at32_wdt_settimeout(time);
		if (ret)
			break;
		/* Enable new time value */
		at32_wdt_start();
		/* fall through */
	case WDIOC_GETTIMEOUT:
		ret = put_user(wdt->timeout, p);
		break;
	case WDIOC_GETSTATUS: /* fall through */
	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, p);
		break;
	case WDIOC_SETOPTIONS:
		ret = get_user(time, p);
		if (ret)
			break;
		if (time & WDIOS_DISABLECARD)
			at32_wdt_stop();
		if (time & WDIOS_ENABLECARD)
			at32_wdt_start();
		ret = 0;
		break;
	}

	return ret;
}

static ssize_t at32_wdt_write(struct file *file, const char *data, size_t len,
				loff_t *ppos)
{
	at32_wdt_pat();
	return len;
}

static const struct file_operations at32_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.ioctl		= at32_wdt_ioctl,
	.open		= at32_wdt_open,
	.release	= at32_wdt_close,
	.write		= at32_wdt_write,
};

static int __init at32_wdt_probe(struct platform_device *pdev)
{
	struct resource	*regs;
	int ret;

	if (wdt) {
		dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
		return -EBUSY;
	}

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!regs) {
		dev_dbg(&pdev->dev, "missing mmio resource\n");
		return -ENXIO;
	}

	wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
	if (!wdt) {
		dev_dbg(&pdev->dev, "no memory for wdt structure\n");
		return -ENOMEM;
	}

	wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
	wdt->users = 0;
	wdt->miscdev.minor = WATCHDOG_MINOR;
	wdt->miscdev.name = "watchdog";
	wdt->miscdev.fops = &at32_wdt_fops;

	if (at32_wdt_settimeout(TIMEOUT_DEFAULT)) {
		at32_wdt_settimeout(TIMEOUT_MAX);
		dev_dbg(&pdev->dev,
			"default timeout invalid, set to %d sec.\n",
			TIMEOUT_MAX);
	}

	ret = misc_register(&wdt->miscdev);
	if (ret) {
		dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
		goto err_register;
	}

	platform_set_drvdata(pdev, wdt);
	wdt->miscdev.parent = &pdev->dev;
	dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p\n", wdt->regs);

	return 0;

err_register:
	kfree(wdt);
	wdt = NULL;
	return ret;
}

static int __exit at32_wdt_remove(struct platform_device *pdev)
{
	if (wdt && platform_get_drvdata(pdev) == wdt) {
		misc_deregister(&wdt->miscdev);
		iounmap(wdt->regs);
		kfree(wdt);
		wdt = NULL;
		platform_set_drvdata(pdev, NULL);
	}

	return 0;
}

static void at32_wdt_shutdown(struct platform_device *pdev)
{
	at32_wdt_stop();
}

#ifdef CONFIG_PM
static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
{
	at32_wdt_stop();
	return 0;
}

static int at32_wdt_resume(struct platform_device *pdev)
{
	if (wdt->users)
		at32_wdt_start();
	return 0;
}
#else
#define at32_wdt_suspend NULL
#define at32_wdt_resume NULL
#endif

static struct platform_driver at32_wdt_driver = {
	.remove		= __exit_p(at32_wdt_remove),
	.suspend	= at32_wdt_suspend,
	.resume		= at32_wdt_resume,
	.driver		= {
		.name	= "at32_wdt",
		.owner	= THIS_MODULE,
	},
	.shutdown	= at32_wdt_shutdown,
};

static int __init at32_wdt_init(void)
{
	return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
}
module_init(at32_wdt_init);

static void __exit at32_wdt_exit(void)
{
	platform_driver_unregister(&at32_wdt_driver);
}
module_exit(at32_wdt_exit);

MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
a9cb3959 HCE	1	/*
	2	* Watchdog driver for Atmel AT32AP700X devices
	3	*
	4	* Copyright (C) 2005-2006 Atmel Corporation
	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
	11	#include <linux/init.h>
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/moduleparam.h>
	15	#include <linux/miscdevice.h>
	16	#include <linux/fs.h>
	17	#include <linux/platform_device.h>
	18	#include <linux/watchdog.h>
c37f2713 AM	19	#include <linux/uaccess.h>
c37f2713 AM	20	#include <linux/io.h>
a9cb3959 HCE	21
	22	#define TIMEOUT_MIN 1
	23	#define TIMEOUT_DEFAULT CONFIG_AT32AP700X_WDT_TIMEOUT
	24	#define TIMEOUT_MAX 2
	25
	26	/* Watchdog registers and write/read macro */
	27	#define WDT_CTRL 0x00
	28	#define WDT_CTRL_EN 0
	29	#define WDT_CTRL_PSEL 8
	30	#define WDT_CTRL_KEY 24
	31
	32	#define WDT_CLR 0x04
	33
	34	#define WDT_BIT(name) (1 << WDT_##name)
	35	#define WDT_BF(name,value) ((value) << WDT_##name)
	36
	37	#define wdt_readl(dev,reg) \
	38	__raw_readl((dev)->regs + WDT_##reg)
	39	#define wdt_writel(dev,reg,value) \
	40	__raw_writel((value), (dev)->regs + WDT_##reg)
	41
	42	struct wdt_at32ap700x {
	43	void __iomem *regs;
	44	int timeout;
	45	int users;
	46	struct miscdevice miscdev;
	47	};
	48
	49	static struct wdt_at32ap700x *wdt;
	50
	51	/*
	52	* Disable the watchdog.
	53	*/
	54	static void inline at32_wdt_stop(void)
	55	{
	56	unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
	57	wdt_writel(wdt, CTRL, psel \| WDT_BF(CTRL_KEY, 0x55));
	58	wdt_writel(wdt, CTRL, psel \| WDT_BF(CTRL_KEY, 0xaa));
	59	}
	60
	61	/*
	62	* Enable and reset the watchdog.
	63	*/
	64	static void inline at32_wdt_start(void)
	65	{
	66	/* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
	67	unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
	68
	69	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
	70	\| WDT_BF(CTRL_PSEL, psel)
	71	\| WDT_BF(CTRL_KEY, 0x55));
	72	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
	73	\| WDT_BF(CTRL_PSEL, psel)
	74	\| WDT_BF(CTRL_KEY, 0xaa));
	75	}
	76
	77	/*
	78	* Pat the watchdog timer.
	79	*/
	80	static void inline at32_wdt_pat(void)
	81	{
	82	wdt_writel(wdt, CLR, 0x42);
	83	}
	84
85	/*
86	* Watchdog device is opened, and watchdog starts running.
87	*/
88	static int at32_wdt_open(struct inode inode, struct file file)
89	{
90	if (test_and_set_bit(1, &wdt->users))
91	return -EBUSY;
92
93	at32_wdt_start();
94	return nonseekable_open(inode, file);
95	}
96
97	/*
98	* Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then
99	* the watchdog is also disabled.
100	*/
101	static int at32_wdt_close(struct inode inode, struct file file)
102	{
103	#ifndef CONFIG_WATCHDOG_NOWAYOUT
104	at32_wdt_stop();
105	#endif
106	clear_bit(1, &wdt->users);
107	return 0;
108	}
109
110	/*
111	* Change the watchdog time interval.
112	*/
113	static int at32_wdt_settimeout(int time)
114	{
115	/*
116	* All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
117	* 2 ^ 16 allowing up to 2 seconds timeout.
118	*/
119	if ((time < TIMEOUT_MIN) \|\| (time > TIMEOUT_MAX))
120	return -EINVAL;
121
c37f2713 AM	122	/*
	123	* Set new watchdog time. It will be used when at32_wdt_start() is
	124	* called.
	125	*/
a9cb3959 HCE	126	wdt->timeout = time;
	127	return 0;
	128	}
	129
	130	static struct watchdog_info at32_wdt_info = {
	131	.identity = "at32ap700x watchdog",
	132	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	133	};
	134
	135	/*
	136	* Handle commands from user-space.
	137	*/
	138	static int at32_wdt_ioctl(struct inode inode, struct file file,
	139	unsigned int cmd, unsigned long arg)
	140	{
	141	int ret = -ENOTTY;
	142	int time;
	143	void __user argp = (void __user )arg;
	144	int __user *p = argp;
	145
c37f2713	146	switch (cmd) {
a9cb3959 HCE	147	case WDIOC_KEEPALIVE:
	148	at32_wdt_pat();
	149	ret = 0;
	150	break;
	151	case WDIOC_GETSUPPORT:
	152	ret = copy_to_user(argp, &at32_wdt_info,
	153	sizeof(at32_wdt_info)) ? -EFAULT : 0;
	154	break;
	155	case WDIOC_SETTIMEOUT:
	156	ret = get_user(time, p);
	157	if (ret)
	158	break;
	159	ret = at32_wdt_settimeout(time);
	160	if (ret)
	161	break;
	162	/* Enable new time value */
	163	at32_wdt_start();
	164	/* fall through */
	165	case WDIOC_GETTIMEOUT:
	166	ret = put_user(wdt->timeout, p);
	167	break;
	168	case WDIOC_GETSTATUS: /* fall through */
	169	case WDIOC_GETBOOTSTATUS:
	170	ret = put_user(0, p);
	171	break;
	172	case WDIOC_SETOPTIONS:
	173	ret = get_user(time, p);
	174	if (ret)
	175	break;
	176	if (time & WDIOS_DISABLECARD)
	177	at32_wdt_stop();
	178	if (time & WDIOS_ENABLECARD)
	179	at32_wdt_start();
	180	ret = 0;
	181	break;
	182	}
	183
	184	return ret;
	185	}
	186
c37f2713 AM	187	static ssize_t at32_wdt_write(struct file file, const char data, size_t len,
c37f2713 AM	188	loff_t *ppos)
a9cb3959 HCE	189	{
	190	at32_wdt_pat();
	191	return len;
	192	}
	193
	194	static const struct file_operations at32_wdt_fops = {
	195	.owner = THIS_MODULE,
	196	.llseek = no_llseek,
	197	.ioctl = at32_wdt_ioctl,
	198	.open = at32_wdt_open,
	199	.release = at32_wdt_close,
	200	.write = at32_wdt_write,
	201	};
	202
	203	static int __init at32_wdt_probe(struct platform_device *pdev)
	204	{
	205	struct resource *regs;
	206	int ret;
	207
	208	if (wdt) {
	209	dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
	210	return -EBUSY;
	211	}
	212
	213	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	214	if (!regs) {
	215	dev_dbg(&pdev->dev, "missing mmio resource\n");
	216	return -ENXIO;
	217	}
	218
	219	wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
	220	if (!wdt) {
	221	dev_dbg(&pdev->dev, "no memory for wdt structure\n");
	222	return -ENOMEM;
	223	}
	224
	225	wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
	226	wdt->users = 0;
	227	wdt->miscdev.minor = WATCHDOG_MINOR;
	228	wdt->miscdev.name = "watchdog";
	229	wdt->miscdev.fops = &at32_wdt_fops;
	230
	231	if (at32_wdt_settimeout(TIMEOUT_DEFAULT)) {
	232	at32_wdt_settimeout(TIMEOUT_MAX);
	233	dev_dbg(&pdev->dev,
	234	"default timeout invalid, set to %d sec.\n",
	235	TIMEOUT_MAX);
	236	}
	237
	238	ret = misc_register(&wdt->miscdev);
	239	if (ret) {
	240	dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
	241	goto err_register;
	242	}
	243
	244	platform_set_drvdata(pdev, wdt);
	245	wdt->miscdev.parent = &pdev->dev;
	246	dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p\n", wdt->regs);
	247
	248	return 0;
	249
	250	err_register:
	251	kfree(wdt);
	252	wdt = NULL;
253	return ret;
254	}
255
256	static int __exit at32_wdt_remove(struct platform_device *pdev)
257	{
258	if (wdt && platform_get_drvdata(pdev) == wdt) {
259	misc_deregister(&wdt->miscdev);
ff732316	260	iounmap(wdt->regs);
a9cb3959 HCE	261	kfree(wdt);
	262	wdt = NULL;
	263	platform_set_drvdata(pdev, NULL);
	264	}
	265
	266	return 0;
	267	}
	268
	269	static void at32_wdt_shutdown(struct platform_device *pdev)
	270	{
	271	at32_wdt_stop();
	272	}
	273
	274	#ifdef CONFIG_PM
	275	static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
	276	{
	277	at32_wdt_stop();
	278	return 0;
	279	}
	280
	281	static int at32_wdt_resume(struct platform_device *pdev)
	282	{
	283	if (wdt->users)
	284	at32_wdt_start();
	285	return 0;
	286	}
97a2a2ea AM	287	#else
	288	#define at32_wdt_suspend NULL
	289	#define at32_wdt_resume NULL
a9cb3959 HCE	290	#endif
	291
	292	static struct platform_driver at32_wdt_driver = {
	293	.remove = __exit_p(at32_wdt_remove),
a9cb3959 HCE	294	.suspend = at32_wdt_suspend,
a9cb3959 HCE	295	.resume = at32_wdt_resume,
a9cb3959 HCE	296	.driver = {
	297	.name = "at32_wdt",
	298	.owner = THIS_MODULE,
	299	},
	300	.shutdown = at32_wdt_shutdown,
	301	};
	302
	303	static int __init at32_wdt_init(void)
	304	{
	305	return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
	306	}
	307	module_init(at32_wdt_init);
	308
	309	static void __exit at32_wdt_exit(void)
	310	{
	311	platform_driver_unregister(&at32_wdt_driver);
	312	}
	313	module_exit(at32_wdt_exit);
	314
	315	MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
	316	MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
	317	MODULE_LICENSE("GPL");
	318	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);