[mirror_ubuntu-bionic-kernel.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_MAX		2
#define TIMEOUT_DEFAULT		TIMEOUT_MAX

/* module parameters */
static int timeout =  TIMEOUT_DEFAULT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
		"Timeout value. Limited to be 1 or 2 seconds. (default="
		__MODULE_STRING(TIMEOUT_DEFAULT) ")");

/* 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 inline void 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 inline void 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 inline void 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);
	if (!wdt->regs) {
		ret = -ENOMEM;
		dev_dbg(&pdev->dev, "could not map I/O memory\n");
		goto err_free;
	}
	wdt->users = 0;
	wdt->miscdev.minor = WATCHDOG_MINOR;
	wdt->miscdev.name = "watchdog";
	wdt->miscdev.fops = &at32_wdt_fops;

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

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

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

	return 0;

err_iounmap:
	iounmap(wdt->regs);
err_free:
	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
a9cb3959 HCE	22	#define TIMEOUT_MIN 1
a9cb3959	23	#define TIMEOUT_MAX 2
726c9f61 WVS	24	#define TIMEOUT_DEFAULT TIMEOUT_MAX
	25
	26	/* module parameters */
	27	static int timeout = TIMEOUT_DEFAULT;
	28	module_param(timeout, int, 0);
	29	MODULE_PARM_DESC(timeout,
	30	"Timeout value. Limited to be 1 or 2 seconds. (default="
	31	__MODULE_STRING(TIMEOUT_DEFAULT) ")");
a9cb3959 HCE	32
	33	/* Watchdog registers and write/read macro */
	34	#define WDT_CTRL 0x00
	35	#define WDT_CTRL_EN 0
	36	#define WDT_CTRL_PSEL 8
	37	#define WDT_CTRL_KEY 24
	38
	39	#define WDT_CLR 0x04
	40
	41	#define WDT_BIT(name) (1 << WDT_##name)
c0ead7e0	42	#define WDT_BF(name, value) ((value) << WDT_##name)
a9cb3959	43
c0ead7e0	44	#define wdt_readl(dev, reg) \
a9cb3959	45	__raw_readl((dev)->regs + WDT_##reg)
c0ead7e0	46	#define wdt_writel(dev, reg, value) \
a9cb3959 HCE	47	__raw_writel((value), (dev)->regs + WDT_##reg)
	48
	49	struct wdt_at32ap700x {
	50	void __iomem *regs;
	51	int timeout;
	52	int users;
	53	struct miscdevice miscdev;
	54	};
	55
	56	static struct wdt_at32ap700x *wdt;
	57
	58	/*
	59	* Disable the watchdog.
	60	*/
c0ead7e0	61	static inline void at32_wdt_stop(void)
a9cb3959 HCE	62	{
	63	unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
	64	wdt_writel(wdt, CTRL, psel \| WDT_BF(CTRL_KEY, 0x55));
	65	wdt_writel(wdt, CTRL, psel \| WDT_BF(CTRL_KEY, 0xaa));
	66	}
	67
	68	/*
	69	* Enable and reset the watchdog.
	70	*/
c0ead7e0	71	static inline void at32_wdt_start(void)
a9cb3959 HCE	72	{
	73	/* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
	74	unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
	75
	76	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
	77	\| WDT_BF(CTRL_PSEL, psel)
	78	\| WDT_BF(CTRL_KEY, 0x55));
	79	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
	80	\| WDT_BF(CTRL_PSEL, psel)
	81	\| WDT_BF(CTRL_KEY, 0xaa));
	82	}
	83
	84	/*
	85	* Pat the watchdog timer.
	86	*/
c0ead7e0	87	static inline void at32_wdt_pat(void)
a9cb3959 HCE	88	{
	89	wdt_writel(wdt, CLR, 0x42);
	90	}
	91
	92	/*
	93	* Watchdog device is opened, and watchdog starts running.
	94	*/
	95	static int at32_wdt_open(struct inode inode, struct file file)
	96	{
	97	if (test_and_set_bit(1, &wdt->users))
	98	return -EBUSY;
	99
	100	at32_wdt_start();
	101	return nonseekable_open(inode, file);
	102	}
	103
	104	/*
	105	* Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then
	106	* the watchdog is also disabled.
	107	*/
	108	static int at32_wdt_close(struct inode inode, struct file file)
	109	{
	110	#ifndef CONFIG_WATCHDOG_NOWAYOUT
	111	at32_wdt_stop();
	112	#endif
	113	clear_bit(1, &wdt->users);
	114	return 0;
	115	}
	116
	117	/*
	118	* Change the watchdog time interval.
	119	*/
	120	static int at32_wdt_settimeout(int time)
	121	{
	122	/*
	123	* All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
	124	* 2 ^ 16 allowing up to 2 seconds timeout.
	125	*/
	126	if ((time < TIMEOUT_MIN) \|\| (time > TIMEOUT_MAX))
	127	return -EINVAL;
	128
c37f2713 AM	129	/*
	130	* Set new watchdog time. It will be used when at32_wdt_start() is
	131	* called.
	132	*/
a9cb3959 HCE	133	wdt->timeout = time;
	134	return 0;
	135	}
	136
	137	static struct watchdog_info at32_wdt_info = {
	138	.identity = "at32ap700x watchdog",
	139	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	140	};
	141
	142	/*
	143	* Handle commands from user-space.
	144	*/
	145	static int at32_wdt_ioctl(struct inode inode, struct file file,
	146	unsigned int cmd, unsigned long arg)
	147	{
	148	int ret = -ENOTTY;
	149	int time;
	150	void __user argp = (void __user )arg;
	151	int __user *p = argp;
	152
c37f2713	153	switch (cmd) {
a9cb3959 HCE	154	case WDIOC_KEEPALIVE:
	155	at32_wdt_pat();
	156	ret = 0;
	157	break;
	158	case WDIOC_GETSUPPORT:
	159	ret = copy_to_user(argp, &at32_wdt_info,
	160	sizeof(at32_wdt_info)) ? -EFAULT : 0;
	161	break;
	162	case WDIOC_SETTIMEOUT:
	163	ret = get_user(time, p);
	164	if (ret)
	165	break;
	166	ret = at32_wdt_settimeout(time);
	167	if (ret)
	168	break;
	169	/* Enable new time value */
	170	at32_wdt_start();
	171	/* fall through */
	172	case WDIOC_GETTIMEOUT:
	173	ret = put_user(wdt->timeout, p);
	174	break;
	175	case WDIOC_GETSTATUS: /* fall through */
	176	case WDIOC_GETBOOTSTATUS:
	177	ret = put_user(0, p);
	178	break;
	179	case WDIOC_SETOPTIONS:
	180	ret = get_user(time, p);
	181	if (ret)
	182	break;
	183	if (time & WDIOS_DISABLECARD)
	184	at32_wdt_stop();
	185	if (time & WDIOS_ENABLECARD)
	186	at32_wdt_start();
	187	ret = 0;
	188	break;
	189	}
	190
	191	return ret;
	192	}
	193
c37f2713 AM	194	static ssize_t at32_wdt_write(struct file file, const char data, size_t len,
c37f2713 AM	195	loff_t *ppos)
a9cb3959 HCE	196	{
	197	at32_wdt_pat();
	198	return len;
	199	}
	200
	201	static const struct file_operations at32_wdt_fops = {
	202	.owner = THIS_MODULE,
	203	.llseek = no_llseek,
	204	.ioctl = at32_wdt_ioctl,
	205	.open = at32_wdt_open,
	206	.release = at32_wdt_close,
	207	.write = at32_wdt_write,
	208	};
	209
	210	static int __init at32_wdt_probe(struct platform_device *pdev)
	211	{
	212	struct resource *regs;
	213	int ret;
	214
	215	if (wdt) {
	216	dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
	217	return -EBUSY;
	218	}
	219
	220	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	221	if (!regs) {
	222	dev_dbg(&pdev->dev, "missing mmio resource\n");
	223	return -ENXIO;
	224	}
	225
	226	wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
	227	if (!wdt) {
	228	dev_dbg(&pdev->dev, "no memory for wdt structure\n");
	229	return -ENOMEM;
	230	}
	231
	232	wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
47d17763 HCE	233	if (!wdt->regs) {
	234	ret = -ENOMEM;
	235	dev_dbg(&pdev->dev, "could not map I/O memory\n");
	236	goto err_free;
	237	}
a9cb3959 HCE	238	wdt->users = 0;
	239	wdt->miscdev.minor = WATCHDOG_MINOR;
	240	wdt->miscdev.name = "watchdog";
	241	wdt->miscdev.fops = &at32_wdt_fops;
	242
726c9f61 WVS	243	if (at32_wdt_settimeout(timeout)) {
726c9f61 WVS	244	at32_wdt_settimeout(TIMEOUT_DEFAULT);
a9cb3959 HCE	245	dev_dbg(&pdev->dev,
a9cb3959 HCE	246	"default timeout invalid, set to %d sec.\n",
726c9f61	247	TIMEOUT_DEFAULT);
a9cb3959 HCE	248	}
	249
	250	ret = misc_register(&wdt->miscdev);
	251	if (ret) {
	252	dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
47d17763	253	goto err_iounmap;
a9cb3959 HCE	254	}
	255
	256	platform_set_drvdata(pdev, wdt);
	257	wdt->miscdev.parent = &pdev->dev;
726c9f61 WVS	258	dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p, timeout %d sec\n",
726c9f61 WVS	259	wdt->regs, wdt->timeout);
a9cb3959 HCE	260
	261	return 0;
	262
47d17763 HCE	263	err_iounmap:
	264	iounmap(wdt->regs);
	265	err_free:
a9cb3959 HCE	266	kfree(wdt);
	267	wdt = NULL;
	268	return ret;
	269	}
	270
	271	static int __exit at32_wdt_remove(struct platform_device *pdev)
	272	{
	273	if (wdt && platform_get_drvdata(pdev) == wdt) {
	274	misc_deregister(&wdt->miscdev);
ff732316	275	iounmap(wdt->regs);
a9cb3959 HCE	276	kfree(wdt);
	277	wdt = NULL;
	278	platform_set_drvdata(pdev, NULL);
	279	}
	280
	281	return 0;
	282	}
	283
	284	static void at32_wdt_shutdown(struct platform_device *pdev)
	285	{
	286	at32_wdt_stop();
	287	}
	288
	289	#ifdef CONFIG_PM
	290	static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
	291	{
	292	at32_wdt_stop();
	293	return 0;
	294	}
	295
	296	static int at32_wdt_resume(struct platform_device *pdev)
	297	{
	298	if (wdt->users)
	299	at32_wdt_start();
	300	return 0;
	301	}
97a2a2ea AM	302	#else
	303	#define at32_wdt_suspend NULL
	304	#define at32_wdt_resume NULL
a9cb3959 HCE	305	#endif
	306
	307	static struct platform_driver at32_wdt_driver = {
	308	.remove = __exit_p(at32_wdt_remove),
a9cb3959 HCE	309	.suspend = at32_wdt_suspend,
a9cb3959 HCE	310	.resume = at32_wdt_resume,
a9cb3959 HCE	311	.driver = {
	312	.name = "at32_wdt",
	313	.owner = THIS_MODULE,
	314	},
	315	.shutdown = at32_wdt_shutdown,
	316	};
	317
	318	static int __init at32_wdt_init(void)
	319	{
	320	return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
	321	}
	322	module_init(at32_wdt_init);
	323
	324	static void __exit at32_wdt_exit(void)
	325	{
	326	platform_driver_unregister(&at32_wdt_driver);
	327	}
	328	module_exit(at32_wdt_exit);
	329
	330	MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
	331	MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
	332	MODULE_LICENSE("GPL");
	333	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);