[deliverable/linux.git] / drivers / watchdog / ath79_wdt.c

/*
 * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
 *
 * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
 * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
 *
 * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
 *	Author: Deepak Saxena <dsaxena@plexity.net>
 *	Copyright 2004 (c) MontaVista, Software, Inc.
 *
 * which again was based on sa1100 driver,
 *	Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
 *
 * 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/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_platform.h>

#define DRIVER_NAME	"ath79-wdt"

#define WDT_TIMEOUT	15	/* seconds */

#define WDOG_REG_CTRL		0x00
#define WDOG_REG_TIMER		0x04

#define WDOG_CTRL_LAST_RESET	BIT(31)
#define WDOG_CTRL_ACTION_MASK	3
#define WDOG_CTRL_ACTION_NONE	0	/* no action */
#define WDOG_CTRL_ACTION_GPI	1	/* general purpose interrupt */
#define WDOG_CTRL_ACTION_NMI	2	/* NMI */
#define WDOG_CTRL_ACTION_FCR	3	/* full chip reset */

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) ")");

static int timeout = WDT_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
			  "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");

static unsigned long wdt_flags;

#define WDT_FLAGS_BUSY		0
#define WDT_FLAGS_EXPECT_CLOSE	1

static struct clk *wdt_clk;
static unsigned long wdt_freq;
static int boot_status;
static int max_timeout;
static void __iomem *wdt_base;

static inline void ath79_wdt_wr(unsigned reg, u32 val)
{
	iowrite32(val, wdt_base + reg);
}

static inline u32 ath79_wdt_rr(unsigned reg)
{
	return ioread32(wdt_base + reg);
}

static inline void ath79_wdt_keepalive(void)
{
	ath79_wdt_wr(WDOG_REG_TIMER, wdt_freq * timeout);
	/* flush write */
	ath79_wdt_rr(WDOG_REG_TIMER);
}

static inline void ath79_wdt_enable(void)
{
	ath79_wdt_keepalive();
	ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_FCR);
	/* flush write */
	ath79_wdt_rr(WDOG_REG_CTRL);
}

static inline void ath79_wdt_disable(void)
{
	ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_NONE);
	/* flush write */
	ath79_wdt_rr(WDOG_REG_CTRL);
}

static int ath79_wdt_set_timeout(int val)
{
	if (val < 1 || val > max_timeout)
		return -EINVAL;

	timeout = val;
	ath79_wdt_keepalive();

	return 0;
}

static int ath79_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
		return -EBUSY;

	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
	ath79_wdt_enable();

	return nonseekable_open(inode, file);
}

static int ath79_wdt_release(struct inode *inode, struct file *file)
{
	if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
		ath79_wdt_disable();
	else {
		pr_crit("device closed unexpectedly, watchdog timer will not stop!\n");
		ath79_wdt_keepalive();
	}

	clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);

	return 0;
}

static ssize_t ath79_wdt_write(struct file *file, const char *data,
				size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);

			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, data + i))
					return -EFAULT;

				if (c == 'V')
					set_bit(WDT_FLAGS_EXPECT_CLOSE,
						&wdt_flags);
			}
		}

		ath79_wdt_keepalive();
	}

	return len;
}

static const struct watchdog_info ath79_wdt_info = {
	.options		= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
				  WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
	.firmware_version	= 0,
	.identity		= "ATH79 watchdog",
};

static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int err;
	int t;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		err = copy_to_user(argp, &ath79_wdt_info,
				   sizeof(ath79_wdt_info)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
		err = put_user(0, p);
		break;

	case WDIOC_GETBOOTSTATUS:
		err = put_user(boot_status, p);
		break;

	case WDIOC_KEEPALIVE:
		ath79_wdt_keepalive();
		err = 0;
		break;

	case WDIOC_SETTIMEOUT:
		err = get_user(t, p);
		if (err)
			break;

		err = ath79_wdt_set_timeout(t);
		if (err)
			break;

		/* fallthrough */
	case WDIOC_GETTIMEOUT:
		err = put_user(timeout, p);
		break;

	default:
		err = -ENOTTY;
		break;
	}

	return err;
}

static const struct file_operations ath79_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= ath79_wdt_write,
	.unlocked_ioctl	= ath79_wdt_ioctl,
	.open		= ath79_wdt_open,
	.release	= ath79_wdt_release,
};

static struct miscdevice ath79_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &ath79_wdt_fops,
};

static int ath79_wdt_probe(struct platform_device *pdev)
{
	struct resource *res;
	u32 ctrl;
	int err;

	if (wdt_base)
		return -EBUSY;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	wdt_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(wdt_base))
		return PTR_ERR(wdt_base);

	wdt_clk = devm_clk_get(&pdev->dev, "wdt");
	if (IS_ERR(wdt_clk))
		return PTR_ERR(wdt_clk);

	err = clk_enable(wdt_clk);
	if (err)
		return err;

	wdt_freq = clk_get_rate(wdt_clk);
	if (!wdt_freq) {
		err = -EINVAL;
		goto err_clk_disable;
	}

	max_timeout = (0xfffffffful / wdt_freq);
	if (timeout < 1 || timeout > max_timeout) {
		timeout = max_timeout;
		dev_info(&pdev->dev,
			"timeout value must be 0 < timeout < %d, using %d\n",
			max_timeout, timeout);
	}

	ctrl = ath79_wdt_rr(WDOG_REG_CTRL);
	boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;

	err = misc_register(&ath79_wdt_miscdev);
	if (err) {
		dev_err(&pdev->dev,
			"unable to register misc device, err=%d\n", err);
		goto err_clk_disable;
	}

	return 0;

err_clk_disable:
	clk_disable(wdt_clk);
	return err;
}

static int ath79_wdt_remove(struct platform_device *pdev)
{
	misc_deregister(&ath79_wdt_miscdev);
	clk_disable(wdt_clk);
	return 0;
}

static void ath97_wdt_shutdown(struct platform_device *pdev)
{
	ath79_wdt_disable();
}

#ifdef CONFIG_OF
static const struct of_device_id ath79_wdt_match[] = {
	{ .compatible = "qca,ar7130-wdt" },
	{},
};
MODULE_DEVICE_TABLE(of, ath79_wdt_match);
#endif

static struct platform_driver ath79_wdt_driver = {
	.probe		= ath79_wdt_probe,
	.remove		= ath79_wdt_remove,
	.shutdown	= ath97_wdt_shutdown,
	.driver		= {
		.name	= DRIVER_NAME,
		.owner	= THIS_MODULE,
		.of_match_table = of_match_ptr(ath79_wdt_match),
	},
};

module_platform_driver(ath79_wdt_driver);

MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
f8394f61 GJ	1	/*
	2	* Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
	3	*
	4	* Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
	5	* Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
	6	*
	7	* This driver was based on: drivers/watchdog/ixp4xx_wdt.c
	8	* Author: Deepak Saxena <dsaxena@plexity.net>
	9	* Copyright 2004 (c) MontaVista, Software, Inc.
	10	*
	11	* which again was based on sa1100 driver,
	12	* Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
	13	*
	14	* This program is free software; you can redistribute it and/or modify it
	15	* under the terms of the GNU General Public License version 2 as published
	16	* by the Free Software Foundation.
	17	*
	18	*/
	19
27c766aa JP	20	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	21
f8394f61 GJ	22	#include <linux/bitops.h>
	23	#include <linux/errno.h>
	24	#include <linux/fs.h>
	25	#include <linux/init.h>
09f5100a	26	#include <linux/io.h>
f8394f61 GJ	27	#include <linux/kernel.h>
	28	#include <linux/miscdevice.h>
	29	#include <linux/module.h>
	30	#include <linux/moduleparam.h>
	31	#include <linux/platform_device.h>
	32	#include <linux/types.h>
	33	#include <linux/watchdog.h>
	34	#include <linux/clk.h>
	35	#include <linux/err.h>
15920d12 GJ	36	#include <linux/of.h>
15920d12 GJ	37	#include <linux/of_platform.h>
f8394f61	38
f8394f61 GJ	39	#define DRIVER_NAME "ath79-wdt"
	40
	41	#define WDT_TIMEOUT 15 /* seconds */
	42
09f5100a GJ	43	#define WDOG_REG_CTRL 0x00
	44	#define WDOG_REG_TIMER 0x04
	45
f8394f61 GJ	46	#define WDOG_CTRL_LAST_RESET BIT(31)
	47	#define WDOG_CTRL_ACTION_MASK 3
	48	#define WDOG_CTRL_ACTION_NONE 0 /* no action */
	49	#define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */
	50	#define WDOG_CTRL_ACTION_NMI 2 /* NMI */
	51	#define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */
	52
86a1e189 WVS	53	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	54	module_param(nowayout, bool, 0);
f8394f61 GJ	55	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
	56	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	57
	58	static int timeout = WDT_TIMEOUT;
	59	module_param(timeout, int, 0);
	60	MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
	61	"(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
	62
	63	static unsigned long wdt_flags;
	64
	65	#define WDT_FLAGS_BUSY 0
	66	#define WDT_FLAGS_EXPECT_CLOSE 1
	67
	68	static struct clk *wdt_clk;
	69	static unsigned long wdt_freq;
	70	static int boot_status;
	71	static int max_timeout;
09f5100a GJ	72	static void __iomem *wdt_base;
	73
	74	static inline void ath79_wdt_wr(unsigned reg, u32 val)
	75	{
	76	iowrite32(val, wdt_base + reg);
	77	}
	78
	79	static inline u32 ath79_wdt_rr(unsigned reg)
	80	{
	81	return ioread32(wdt_base + reg);
	82	}
f8394f61 GJ	83
	84	static inline void ath79_wdt_keepalive(void)
	85	{
09f5100a	86	ath79_wdt_wr(WDOG_REG_TIMER, wdt_freq * timeout);
86955e2b	87	/* flush write */
09f5100a	88	ath79_wdt_rr(WDOG_REG_TIMER);
f8394f61 GJ	89	}
	90
	91	static inline void ath79_wdt_enable(void)
	92	{
	93	ath79_wdt_keepalive();
09f5100a	94	ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_FCR);
86955e2b	95	/* flush write */
09f5100a	96	ath79_wdt_rr(WDOG_REG_CTRL);
f8394f61 GJ	97	}
	98
	99	static inline void ath79_wdt_disable(void)
	100	{
09f5100a	101	ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_NONE);
86955e2b	102	/* flush write */
09f5100a	103	ath79_wdt_rr(WDOG_REG_CTRL);
f8394f61 GJ	104	}
	105
	106	static int ath79_wdt_set_timeout(int val)
	107	{
	108	if (val < 1 \|\| val > max_timeout)
	109	return -EINVAL;
	110
	111	timeout = val;
	112	ath79_wdt_keepalive();
	113
	114	return 0;
	115	}
	116
	117	static int ath79_wdt_open(struct inode inode, struct file file)
	118	{
	119	if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
	120	return -EBUSY;
	121
	122	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
	123	ath79_wdt_enable();
	124
	125	return nonseekable_open(inode, file);
	126	}
	127
	128	static int ath79_wdt_release(struct inode inode, struct file file)
	129	{
	130	if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
	131	ath79_wdt_disable();
	132	else {
27c766aa	133	pr_crit("device closed unexpectedly, watchdog timer will not stop!\n");
f8394f61 GJ	134	ath79_wdt_keepalive();
	135	}
	136
	137	clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
	138	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
	139
	140	return 0;
	141	}
	142
	143	static ssize_t ath79_wdt_write(struct file file, const char data,
	144	size_t len, loff_t *ppos)
	145	{
	146	if (len) {
	147	if (!nowayout) {
	148	size_t i;
	149
	150	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
	151
	152	for (i = 0; i != len; i++) {
	153	char c;
	154
	155	if (get_user(c, data + i))
	156	return -EFAULT;
	157
	158	if (c == 'V')
	159	set_bit(WDT_FLAGS_EXPECT_CLOSE,
	160	&wdt_flags);
	161	}
	162	}
	163
	164	ath79_wdt_keepalive();
	165	}
	166
	167	return len;
	168	}
	169
	170	static const struct watchdog_info ath79_wdt_info = {
	171	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
	172	WDIOF_MAGICCLOSE \| WDIOF_CARDRESET,
	173	.firmware_version = 0,
	174	.identity = "ATH79 watchdog",
	175	};
	176
	177	static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
	178	unsigned long arg)
	179	{
	180	void __user argp = (void __user )arg;
	181	int __user *p = argp;
	182	int err;
	183	int t;
	184
	185	switch (cmd) {
	186	case WDIOC_GETSUPPORT:
	187	err = copy_to_user(argp, &ath79_wdt_info,
	188	sizeof(ath79_wdt_info)) ? -EFAULT : 0;
	189	break;
	190
	191	case WDIOC_GETSTATUS:
	192	err = put_user(0, p);
	193	break;
	194
	195	case WDIOC_GETBOOTSTATUS:
	196	err = put_user(boot_status, p);
	197	break;
198
199	case WDIOC_KEEPALIVE:
200	ath79_wdt_keepalive();
201	err = 0;
202	break;
203
204	case WDIOC_SETTIMEOUT:
205	err = get_user(t, p);
206	if (err)
207	break;
208
209	err = ath79_wdt_set_timeout(t);
210	if (err)
211	break;
212
213	/* fallthrough */
214	case WDIOC_GETTIMEOUT:
215	err = put_user(timeout, p);
216	break;
217
218	default:
219	err = -ENOTTY;
220	break;
221	}
222
223	return err;
224	}
225
226	static const struct file_operations ath79_wdt_fops = {
227	.owner = THIS_MODULE,
228	.llseek = no_llseek,
229	.write = ath79_wdt_write,
230	.unlocked_ioctl = ath79_wdt_ioctl,
231	.open = ath79_wdt_open,
232	.release = ath79_wdt_release,
233	};
234
235	static struct miscdevice ath79_wdt_miscdev = {
236	.minor = WATCHDOG_MINOR,
237	.name = "watchdog",
238	.fops = &ath79_wdt_fops,
239	};
240
2d991a16	241	static int ath79_wdt_probe(struct platform_device *pdev)
f8394f61	242	{
09f5100a	243	struct resource *res;
f8394f61 GJ	244	u32 ctrl;
	245	int err;
	246
09f5100a GJ	247	if (wdt_base)
	248	return -EBUSY;
	249
	250	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
6330c707 SK	251	wdt_base = devm_ioremap_resource(&pdev->dev, res);
	252	if (IS_ERR(wdt_base))
	253	return PTR_ERR(wdt_base);
09f5100a	254
5071a884	255	wdt_clk = devm_clk_get(&pdev->dev, "wdt");
f8394f61 GJ	256	if (IS_ERR(wdt_clk))
	257	return PTR_ERR(wdt_clk);
	258
	259	err = clk_enable(wdt_clk);
	260	if (err)
5071a884	261	return err;
f8394f61 GJ	262
	263	wdt_freq = clk_get_rate(wdt_clk);
	264	if (!wdt_freq) {
	265	err = -EINVAL;
	266	goto err_clk_disable;
	267	}
	268
	269	max_timeout = (0xfffffffful / wdt_freq);
	270	if (timeout < 1 \|\| timeout > max_timeout) {
	271	timeout = max_timeout;
	272	dev_info(&pdev->dev,
	273	"timeout value must be 0 < timeout < %d, using %d\n",
	274	max_timeout, timeout);
	275	}
	276
09f5100a	277	ctrl = ath79_wdt_rr(WDOG_REG_CTRL);
f8394f61 GJ	278	boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
	279
	280	err = misc_register(&ath79_wdt_miscdev);
	281	if (err) {
	282	dev_err(&pdev->dev,
	283	"unable to register misc device, err=%d\n", err);
	284	goto err_clk_disable;
	285	}
	286
	287	return 0;
	288
	289	err_clk_disable:
	290	clk_disable(wdt_clk);
f8394f61 GJ	291	return err;
	292	}
	293
4b12b896	294	static int ath79_wdt_remove(struct platform_device *pdev)
f8394f61 GJ	295	{
	296	misc_deregister(&ath79_wdt_miscdev);
	297	clk_disable(wdt_clk);
f8394f61 GJ	298	return 0;
	299	}
	300
	301	static void ath97_wdt_shutdown(struct platform_device *pdev)
	302	{
	303	ath79_wdt_disable();
	304	}
	305
15920d12 GJ	306	#ifdef CONFIG_OF
	307	static const struct of_device_id ath79_wdt_match[] = {
	308	{ .compatible = "qca,ar7130-wdt" },
	309	{},
	310	};
	311	MODULE_DEVICE_TABLE(of, ath79_wdt_match);
	312	#endif
	313
f8394f61	314	static struct platform_driver ath79_wdt_driver = {
8157becf	315	.probe = ath79_wdt_probe,
82268714	316	.remove = ath79_wdt_remove,
f8394f61 GJ	317	.shutdown = ath97_wdt_shutdown,
	318	.driver = {
	319	.name = DRIVER_NAME,
	320	.owner = THIS_MODULE,
15920d12	321	.of_match_table = of_match_ptr(ath79_wdt_match),
f8394f61 GJ	322	},
	323	};
	324
8157becf	325	module_platform_driver(ath79_wdt_driver);
f8394f61 GJ	326
	327	MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
	328	MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
	329	MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
	330	MODULE_LICENSE("GPL v2");
	331	MODULE_ALIAS("platform:" DRIVER_NAME);
	332	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);