[mirror_ubuntu-bionic-kernel.git] / drivers / watchdog / kempld_wdt.c

/*
 * Kontron PLD watchdog driver
 *
 * Copyright (c) 2010-2013 Kontron Europe GmbH
 * Author: Michael Brunner <michael.brunner@kontron.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Note: From the PLD watchdog point of view timeout and pretimeout are
 *       defined differently than in the kernel.
 *       First the pretimeout stage runs out before the timeout stage gets
 *       active.
 *
 * Kernel/API:                     P-----| pretimeout
 *               |-----------------------T timeout
 * Watchdog:     |-----------------P       pretimeout_stage
 *                                 |-----T timeout_stage
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/mfd/kempld.h>

#define KEMPLD_WDT_STAGE_TIMEOUT(x)	(0x1b + (x) * 4)
#define KEMPLD_WDT_STAGE_CFG(x)		(0x18 + (x))
#define STAGE_CFG_GET_PRESCALER(x)	(((x) & 0x30) >> 4)
#define STAGE_CFG_SET_PRESCALER(x)	(((x) & 0x3) << 4)
#define STAGE_CFG_PRESCALER_MASK	0x30
#define STAGE_CFG_ACTION_MASK		0x7
#define STAGE_CFG_ASSERT		(1 << 3)

#define KEMPLD_WDT_MAX_STAGES		2
#define KEMPLD_WDT_KICK			0x16
#define KEMPLD_WDT_CFG			0x17
#define KEMPLD_WDT_CFG_ENABLE		0x10
#define KEMPLD_WDT_CFG_ENABLE_LOCK	0x8
#define KEMPLD_WDT_CFG_GLOBAL_LOCK	0x80

enum {
	ACTION_NONE = 0,
	ACTION_RESET,
	ACTION_NMI,
	ACTION_SMI,
	ACTION_SCI,
	ACTION_DELAY,
};

enum {
	STAGE_TIMEOUT = 0,
	STAGE_PRETIMEOUT,
};

enum {
	PRESCALER_21 = 0,
	PRESCALER_17,
	PRESCALER_12,
};

const u32 kempld_prescaler[] = {
	[PRESCALER_21] = (1 << 21) - 1,
	[PRESCALER_17] = (1 << 17) - 1,
	[PRESCALER_12] = (1 << 12) - 1,
	0,
};

struct kempld_wdt_stage {
	unsigned int	id;
	u32		mask;
};

struct kempld_wdt_data {
	struct kempld_device_data	*pld;
	struct watchdog_device		wdd;
	unsigned int			pretimeout;
	struct kempld_wdt_stage		stage[KEMPLD_WDT_MAX_STAGES];
#ifdef CONFIG_PM
	u8				pm_status_store;
#endif
};

#define DEFAULT_TIMEOUT		30 /* seconds */
#define DEFAULT_PRETIMEOUT	0

static unsigned int timeout = DEFAULT_TIMEOUT;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. (>=0, default="
	__MODULE_STRING(DEFAULT_TIMEOUT) ")");

static unsigned int pretimeout = DEFAULT_PRETIMEOUT;
module_param(pretimeout, uint, 0);
MODULE_PARM_DESC(pretimeout,
	"Watchdog pretimeout in seconds. (>=0, default="
	__MODULE_STRING(DEFAULT_PRETIMEOUT) ")");

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 kempld_wdt_set_stage_action(struct kempld_wdt_data *wdt_data,
					struct kempld_wdt_stage *stage,
					u8 action)
{
	struct kempld_device_data *pld = wdt_data->pld;
	u8 stage_cfg;

	if (!stage || !stage->mask)
		return -EINVAL;

	kempld_get_mutex(pld);
	stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
	stage_cfg &= ~STAGE_CFG_ACTION_MASK;
	stage_cfg |= (action & STAGE_CFG_ACTION_MASK);

	if (action == ACTION_RESET)
		stage_cfg |= STAGE_CFG_ASSERT;
	else
		stage_cfg &= ~STAGE_CFG_ASSERT;

	kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
	kempld_release_mutex(pld);

	return 0;
}

static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data,
					struct kempld_wdt_stage *stage,
					unsigned int timeout)
{
	struct kempld_device_data *pld = wdt_data->pld;
	u32 prescaler = kempld_prescaler[PRESCALER_21];
	u64 stage_timeout64;
	u32 stage_timeout;
	u32 remainder;
	u8 stage_cfg;

	if (!stage)
		return -EINVAL;

	stage_timeout64 = (u64)timeout * pld->pld_clock;
	remainder = do_div(stage_timeout64, prescaler);
	if (remainder)
		stage_timeout64++;

	if (stage_timeout64 > stage->mask)
		return -EINVAL;

	stage_timeout = stage_timeout64 & stage->mask;

	kempld_get_mutex(pld);
	stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
	stage_cfg &= ~STAGE_CFG_PRESCALER_MASK;
	stage_cfg |= STAGE_CFG_SET_PRESCALER(prescaler);
	kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
	kempld_write32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id),
			stage_timeout);
	kempld_release_mutex(pld);

	return 0;
}

/*
 * kempld_get_mutex must be called prior to calling this function.
 */
static unsigned int kempld_wdt_get_timeout(struct kempld_wdt_data *wdt_data,
						struct kempld_wdt_stage *stage)
{
	struct kempld_device_data *pld = wdt_data->pld;
	unsigned int timeout;
	u64 stage_timeout;
	u32 prescaler;
	u32 remainder;
	u8 stage_cfg;

	if (!stage->mask)
		return 0;

	stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
	stage_timeout = kempld_read32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id));
	prescaler = kempld_prescaler[STAGE_CFG_GET_PRESCALER(stage_cfg)];

	stage_timeout = (stage_timeout & stage->mask) * prescaler;
	remainder = do_div(stage_timeout, pld->pld_clock);
	if (remainder)
		stage_timeout++;

	timeout = stage_timeout;
	WARN_ON_ONCE(timeout != stage_timeout);

	return timeout;
}

static int kempld_wdt_set_timeout(struct watchdog_device *wdd,
					unsigned int timeout)
{
	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
	struct kempld_wdt_stage *pretimeout_stage;
	struct kempld_wdt_stage *timeout_stage;
	int ret;

	timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
	pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];

	if (pretimeout_stage->mask && wdt_data->pretimeout > 0)
		timeout = wdt_data->pretimeout;

	ret = kempld_wdt_set_stage_action(wdt_data, timeout_stage,
						ACTION_RESET);
	if (ret)
		return ret;
	ret = kempld_wdt_set_stage_timeout(wdt_data, timeout_stage,
						timeout);
	if (ret)
		return ret;

	wdd->timeout = timeout;
	return 0;
}

static int kempld_wdt_set_pretimeout(struct watchdog_device *wdd,
					unsigned int pretimeout)
{
	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
	struct kempld_wdt_stage *pretimeout_stage;
	u8 action = ACTION_NONE;
	int ret;

	pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];

	if (!pretimeout_stage->mask)
		return -ENXIO;

	if (pretimeout > wdd->timeout)
		return -EINVAL;

	if (pretimeout > 0)
		action = ACTION_NMI;

	ret = kempld_wdt_set_stage_action(wdt_data, pretimeout_stage,
						action);
	if (ret)
		return ret;
	ret = kempld_wdt_set_stage_timeout(wdt_data, pretimeout_stage,
						wdd->timeout - pretimeout);
	if (ret)
		return ret;

	wdt_data->pretimeout = pretimeout;
	return 0;
}

static void kempld_wdt_update_timeouts(struct kempld_wdt_data *wdt_data)
{
	struct kempld_device_data *pld = wdt_data->pld;
	struct kempld_wdt_stage *pretimeout_stage;
	struct kempld_wdt_stage *timeout_stage;
	unsigned int pretimeout, timeout;

	pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
	timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];

	kempld_get_mutex(pld);
	pretimeout = kempld_wdt_get_timeout(wdt_data, pretimeout_stage);
	timeout = kempld_wdt_get_timeout(wdt_data, timeout_stage);
	kempld_release_mutex(pld);

	if (pretimeout)
		wdt_data->pretimeout = timeout;
	else
		wdt_data->pretimeout = 0;

	wdt_data->wdd.timeout = pretimeout + timeout;
}

static int kempld_wdt_start(struct watchdog_device *wdd)
{
	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
	struct kempld_device_data *pld = wdt_data->pld;
	u8 status;
	int ret;

	ret = kempld_wdt_set_timeout(wdd, wdd->timeout);
	if (ret)
		return ret;

	kempld_get_mutex(pld);
	status = kempld_read8(pld, KEMPLD_WDT_CFG);
	status |= KEMPLD_WDT_CFG_ENABLE;
	kempld_write8(pld, KEMPLD_WDT_CFG, status);
	status = kempld_read8(pld, KEMPLD_WDT_CFG);
	kempld_release_mutex(pld);

	/* Check if the watchdog was enabled */
	if (!(status & KEMPLD_WDT_CFG_ENABLE))
		return -EACCES;

	return 0;
}

static int kempld_wdt_stop(struct watchdog_device *wdd)
{
	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
	struct kempld_device_data *pld = wdt_data->pld;
	u8 status;

	kempld_get_mutex(pld);
	status = kempld_read8(pld, KEMPLD_WDT_CFG);
	status &= ~KEMPLD_WDT_CFG_ENABLE;
	kempld_write8(pld, KEMPLD_WDT_CFG, status);
	status = kempld_read8(pld, KEMPLD_WDT_CFG);
	kempld_release_mutex(pld);

	/* Check if the watchdog was disabled */
	if (status & KEMPLD_WDT_CFG_ENABLE)
		return -EACCES;

	return 0;
}

static int kempld_wdt_keepalive(struct watchdog_device *wdd)
{
	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
	struct kempld_device_data *pld = wdt_data->pld;

	kempld_get_mutex(pld);
	kempld_write8(pld, KEMPLD_WDT_KICK, 'K');
	kempld_release_mutex(pld);

	return 0;
}

static long kempld_wdt_ioctl(struct watchdog_device *wdd, unsigned int cmd,
				unsigned long arg)
{
	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
	void __user *argp = (void __user *)arg;
	int ret = -ENOIOCTLCMD;
	int __user *p = argp;
	int new_value;

	switch (cmd) {
	case WDIOC_SETPRETIMEOUT:
		if (get_user(new_value, p))
			return -EFAULT;
		ret = kempld_wdt_set_pretimeout(wdd, new_value);
		if (ret)
			return ret;
		ret = kempld_wdt_keepalive(wdd);
		break;
	case WDIOC_GETPRETIMEOUT:
		ret = put_user(wdt_data->pretimeout, (int *)arg);
		break;
	}

	return ret;
}

static int kempld_wdt_probe_stages(struct watchdog_device *wdd)
{
	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
	struct kempld_device_data *pld = wdt_data->pld;
	struct kempld_wdt_stage *pretimeout_stage;
	struct kempld_wdt_stage *timeout_stage;
	u8 index, data, data_orig;
	u32 mask;
	int i, j;

	pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
	timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];

	pretimeout_stage->mask = 0;
	timeout_stage->mask = 0;

	for (i = 0; i < 3; i++) {
		index = KEMPLD_WDT_STAGE_TIMEOUT(i);
		mask = 0;

		kempld_get_mutex(pld);
		/* Probe each byte individually. */
		for (j = 0; j < 4; j++) {
			data_orig = kempld_read8(pld, index + j);
			kempld_write8(pld, index + j, 0x00);
			data = kempld_read8(pld, index + j);
			/* A failed write means this byte is reserved */
			if (data != 0x00)
				break;
			kempld_write8(pld, index + j, data_orig);
			mask |= 0xff << (j * 8);
		}
		kempld_release_mutex(pld);

		/* Assign available stages to timeout and pretimeout */
		if (!timeout_stage->mask) {
			timeout_stage->mask = mask;
			timeout_stage->id = i;
		} else {
			if (pld->feature_mask & KEMPLD_FEATURE_BIT_NMI) {
				pretimeout_stage->mask = timeout_stage->mask;
				timeout_stage->mask = mask;
				pretimeout_stage->id = timeout_stage->id;
				timeout_stage->id = i;
			}
			break;
		}
	}

	if (!timeout_stage->mask)
		return -ENODEV;

	return 0;
}

static struct watchdog_info kempld_wdt_info = {
	.identity	= "KEMPLD Watchdog",
	.options	= WDIOF_SETTIMEOUT |
			WDIOF_KEEPALIVEPING |
			WDIOF_MAGICCLOSE |
			WDIOF_PRETIMEOUT
};

static struct watchdog_ops kempld_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= kempld_wdt_start,
	.stop		= kempld_wdt_stop,
	.ping		= kempld_wdt_keepalive,
	.set_timeout	= kempld_wdt_set_timeout,
	.ioctl		= kempld_wdt_ioctl,
};

static int kempld_wdt_probe(struct platform_device *pdev)
{
	struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent);
	struct kempld_wdt_data *wdt_data;
	struct device *dev = &pdev->dev;
	struct watchdog_device *wdd;
	u8 status;
	int ret = 0;

	wdt_data = devm_kzalloc(dev, sizeof(*wdt_data), GFP_KERNEL);
	if (!wdt_data)
		return -ENOMEM;

	wdt_data->pld = pld;
	wdd = &wdt_data->wdd;
	wdd->parent = dev;

	kempld_get_mutex(pld);
	status = kempld_read8(pld, KEMPLD_WDT_CFG);
	kempld_release_mutex(pld);

	/* Enable nowayout if watchdog is already locked */
	if (status & (KEMPLD_WDT_CFG_ENABLE_LOCK |
			KEMPLD_WDT_CFG_GLOBAL_LOCK)) {
		if (!nowayout)
			dev_warn(dev,
				"Forcing nowayout - watchdog lock enabled!\n");
		nowayout = true;
	}

	wdd->info = &kempld_wdt_info;
	wdd->ops = &kempld_wdt_ops;

	watchdog_set_drvdata(wdd, wdt_data);
	watchdog_set_nowayout(wdd, nowayout);

	ret = kempld_wdt_probe_stages(wdd);
	if (ret)
		return ret;

	kempld_wdt_set_timeout(wdd, timeout);
	kempld_wdt_set_pretimeout(wdd, pretimeout);

	/* Check if watchdog is already enabled */
	if (status & KEMPLD_WDT_CFG_ENABLE) {
		/* Get current watchdog settings */
		kempld_wdt_update_timeouts(wdt_data);
		dev_info(dev, "Watchdog was already enabled\n");
	}

	platform_set_drvdata(pdev, wdt_data);
	ret = watchdog_register_device(wdd);
	if (ret)
		return ret;

	dev_info(dev, "Watchdog registered with %ds timeout\n", wdd->timeout);

	return 0;
}

static void kempld_wdt_shutdown(struct platform_device *pdev)
{
	struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);

	kempld_wdt_stop(&wdt_data->wdd);
}

static int kempld_wdt_remove(struct platform_device *pdev)
{
	struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
	struct watchdog_device *wdd = &wdt_data->wdd;
	int ret = 0;

	if (!nowayout)
		ret = kempld_wdt_stop(wdd);
	watchdog_unregister_device(wdd);

	return ret;
}

#ifdef CONFIG_PM
/* Disable watchdog if it is active during suspend */
static int kempld_wdt_suspend(struct platform_device *pdev,
				pm_message_t message)
{
	struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
	struct kempld_device_data *pld = wdt_data->pld;
	struct watchdog_device *wdd = &wdt_data->wdd;

	kempld_get_mutex(pld);
	wdt_data->pm_status_store = kempld_read8(pld, KEMPLD_WDT_CFG);
	kempld_release_mutex(pld);

	kempld_wdt_update_timeouts(wdt_data);

	if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
		return kempld_wdt_stop(wdd);

	return 0;
}

/* Enable watchdog and configure it if necessary */
static int kempld_wdt_resume(struct platform_device *pdev)
{
	struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
	struct watchdog_device *wdd = &wdt_data->wdd;

	/*
	 * If watchdog was stopped before suspend be sure it gets disabled
	 * again, for the case BIOS has enabled it during resume
	 */
	if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
		return kempld_wdt_start(wdd);
	else
		return kempld_wdt_stop(wdd);
}
#else
#define kempld_wdt_suspend	NULL
#define kempld_wdt_resume	NULL
#endif

static struct platform_driver kempld_wdt_driver = {
	.driver		= {
		.name	= "kempld-wdt",
		.owner	= THIS_MODULE,
	},
	.probe		= kempld_wdt_probe,
	.remove		= kempld_wdt_remove,
	.shutdown	= kempld_wdt_shutdown,
	.suspend	= kempld_wdt_suspend,
	.resume		= kempld_wdt_resume,
};

module_platform_driver(kempld_wdt_driver);

MODULE_DESCRIPTION("KEM PLD Watchdog Driver");
MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
e51c288e KS	1	/*
	2	* Kontron PLD watchdog driver
	3	*
	4	* Copyright (c) 2010-2013 Kontron Europe GmbH
	5	* Author: Michael Brunner <michael.brunner@kontron.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License 2 as published
	9	* by the Free Software Foundation.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* Note: From the PLD watchdog point of view timeout and pretimeout are
	17	* defined differently than in the kernel.
	18	* First the pretimeout stage runs out before the timeout stage gets
	19	* active.
	20	*
	21	* Kernel/API: P-----\| pretimeout
	22	* \|-----------------------T timeout
	23	* Watchdog: \|-----------------P pretimeout_stage
	24	* \|-----T timeout_stage
	25	*/
	26
	27	#include <linux/module.h>
	28	#include <linux/moduleparam.h>
	29	#include <linux/miscdevice.h>
	30	#include <linux/uaccess.h>
	31	#include <linux/watchdog.h>
	32	#include <linux/platform_device.h>
	33	#include <linux/mfd/kempld.h>
	34
	35	#define KEMPLD_WDT_STAGE_TIMEOUT(x) (0x1b + (x) * 4)
	36	#define KEMPLD_WDT_STAGE_CFG(x) (0x18 + (x))
	37	#define STAGE_CFG_GET_PRESCALER(x) (((x) & 0x30) >> 4)
4c4e4566	38	#define STAGE_CFG_SET_PRESCALER(x) (((x) & 0x3) << 4)
e51c288e KS	39	#define STAGE_CFG_PRESCALER_MASK 0x30
	40	#define STAGE_CFG_ACTION_MASK 0x7
	41	#define STAGE_CFG_ASSERT (1 << 3)
	42
	43	#define KEMPLD_WDT_MAX_STAGES 2
	44	#define KEMPLD_WDT_KICK 0x16
	45	#define KEMPLD_WDT_CFG 0x17
	46	#define KEMPLD_WDT_CFG_ENABLE 0x10
	47	#define KEMPLD_WDT_CFG_ENABLE_LOCK 0x8
	48	#define KEMPLD_WDT_CFG_GLOBAL_LOCK 0x80
	49
	50	enum {
	51	ACTION_NONE = 0,
	52	ACTION_RESET,
	53	ACTION_NMI,
	54	ACTION_SMI,
	55	ACTION_SCI,
	56	ACTION_DELAY,
	57	};
	58
	59	enum {
	60	STAGE_TIMEOUT = 0,
	61	STAGE_PRETIMEOUT,
	62	};
	63
	64	enum {
	65	PRESCALER_21 = 0,
	66	PRESCALER_17,
	67	PRESCALER_12,
	68	};
	69
	70	const u32 kempld_prescaler[] = {
	71	[PRESCALER_21] = (1 << 21) - 1,
	72	[PRESCALER_17] = (1 << 17) - 1,
	73	[PRESCALER_12] = (1 << 12) - 1,
	74	0,
	75	};
	76
	77	struct kempld_wdt_stage {
	78	unsigned int id;
	79	u32 mask;
	80	};
	81
	82	struct kempld_wdt_data {
	83	struct kempld_device_data *pld;
	84	struct watchdog_device wdd;
	85	unsigned int pretimeout;
	86	struct kempld_wdt_stage stage[KEMPLD_WDT_MAX_STAGES];
	87	#ifdef CONFIG_PM
	88	u8 pm_status_store;
	89	#endif
	90	};
	91
	92	#define DEFAULT_TIMEOUT 30 /* seconds */
	93	#define DEFAULT_PRETIMEOUT 0
	94
	95	static unsigned int timeout = DEFAULT_TIMEOUT;
	96	module_param(timeout, uint, 0);
	97	MODULE_PARM_DESC(timeout,
	98	"Watchdog timeout in seconds. (>=0, default="
	99	__MODULE_STRING(DEFAULT_TIMEOUT) ")");
	100
	101	static unsigned int pretimeout = DEFAULT_PRETIMEOUT;
	102	module_param(pretimeout, uint, 0);
103	MODULE_PARM_DESC(pretimeout,
104	"Watchdog pretimeout in seconds. (>=0, default="
105	__MODULE_STRING(DEFAULT_PRETIMEOUT) ")");
106
107	static bool nowayout = WATCHDOG_NOWAYOUT;
108	module_param(nowayout, bool, 0);
109	MODULE_PARM_DESC(nowayout,
110	"Watchdog cannot be stopped once started (default="
111	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
112
113	static int kempld_wdt_set_stage_action(struct kempld_wdt_data *wdt_data,
114	struct kempld_wdt_stage *stage,
115	u8 action)
116	{
117	struct kempld_device_data *pld = wdt_data->pld;
118	u8 stage_cfg;
119
120	if (!stage \|\| !stage->mask)
121	return -EINVAL;
122
123	kempld_get_mutex(pld);
124	stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
125	stage_cfg &= ~STAGE_CFG_ACTION_MASK;
126	stage_cfg \|= (action & STAGE_CFG_ACTION_MASK);
127
128	if (action == ACTION_RESET)
129	stage_cfg \|= STAGE_CFG_ASSERT;
130	else
131	stage_cfg &= ~STAGE_CFG_ASSERT;
132
133	kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
134	kempld_release_mutex(pld);
135
136	return 0;
137	}
138
139	static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data,
140	struct kempld_wdt_stage *stage,
141	unsigned int timeout)
142	{
143	struct kempld_device_data *pld = wdt_data->pld;
144	u32 prescaler = kempld_prescaler[PRESCALER_21];
145	u64 stage_timeout64;
146	u32 stage_timeout;
147	u32 remainder;
148	u8 stage_cfg;
149
150	if (!stage)
151	return -EINVAL;
152
153	stage_timeout64 = (u64)timeout * pld->pld_clock;
154	remainder = do_div(stage_timeout64, prescaler);
155	if (remainder)
156	stage_timeout64++;
157
158	if (stage_timeout64 > stage->mask)
159	return -EINVAL;
160
161	stage_timeout = stage_timeout64 & stage->mask;
162
163	kempld_get_mutex(pld);
164	stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
165	stage_cfg &= ~STAGE_CFG_PRESCALER_MASK;
166	stage_cfg \|= STAGE_CFG_SET_PRESCALER(prescaler);
167	kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
168	kempld_write32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id),
169	stage_timeout);
170	kempld_release_mutex(pld);
171
172	return 0;
173	}
174
175	/*
176	* kempld_get_mutex must be called prior to calling this function.
177	*/
178	static unsigned int kempld_wdt_get_timeout(struct kempld_wdt_data *wdt_data,
179	struct kempld_wdt_stage *stage)
180	{
181	struct kempld_device_data *pld = wdt_data->pld;
182	unsigned int timeout;
183	u64 stage_timeout;
184	u32 prescaler;
185	u32 remainder;
186	u8 stage_cfg;
187
188	if (!stage->mask)
189	return 0;
190
191	stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
192	stage_timeout = kempld_read32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id));
193	prescaler = kempld_prescaler[STAGE_CFG_GET_PRESCALER(stage_cfg)];
194
195	stage_timeout = (stage_timeout & stage->mask) * prescaler;
196	remainder = do_div(stage_timeout, pld->pld_clock);
197	if (remainder)
198	stage_timeout++;
199
200	timeout = stage_timeout;
201	WARN_ON_ONCE(timeout != stage_timeout);
202
203	return timeout;
204	}
205
206	static int kempld_wdt_set_timeout(struct watchdog_device *wdd,
207	unsigned int timeout)
208	{
209	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
210	struct kempld_wdt_stage *pretimeout_stage;
211	struct kempld_wdt_stage *timeout_stage;
212	int ret;
213
214	timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
215	pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
216
217	if (pretimeout_stage->mask && wdt_data->pretimeout > 0)
218	timeout = wdt_data->pretimeout;
219
220	ret = kempld_wdt_set_stage_action(wdt_data, timeout_stage,
221	ACTION_RESET);
222	if (ret)
223	return ret;
224	ret = kempld_wdt_set_stage_timeout(wdt_data, timeout_stage,
225	timeout);
226	if (ret)
227	return ret;
228
229	wdd->timeout = timeout;
230	return 0;
231	}
232
233	static int kempld_wdt_set_pretimeout(struct watchdog_device *wdd,
234	unsigned int pretimeout)
235	{
236	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
237	struct kempld_wdt_stage *pretimeout_stage;
238	u8 action = ACTION_NONE;
239	int ret;
240
241	pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
242
243	if (!pretimeout_stage->mask)
244	return -ENXIO;
245
246	if (pretimeout > wdd->timeout)
247	return -EINVAL;
248
249	if (pretimeout > 0)
250	action = ACTION_NMI;
251
252	ret = kempld_wdt_set_stage_action(wdt_data, pretimeout_stage,
253	action);
254	if (ret)
255	return ret;
256	ret = kempld_wdt_set_stage_timeout(wdt_data, pretimeout_stage,
257	wdd->timeout - pretimeout);
258	if (ret)
259	return ret;
260
261	wdt_data->pretimeout = pretimeout;
262	return 0;
263	}
264
265	static void kempld_wdt_update_timeouts(struct kempld_wdt_data *wdt_data)
266	{
267	struct kempld_device_data *pld = wdt_data->pld;
268	struct kempld_wdt_stage *pretimeout_stage;
269	struct kempld_wdt_stage *timeout_stage;
270	unsigned int pretimeout, timeout;
271
272	pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
273	timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
274
275	kempld_get_mutex(pld);
276	pretimeout = kempld_wdt_get_timeout(wdt_data, pretimeout_stage);
277	timeout = kempld_wdt_get_timeout(wdt_data, timeout_stage);
278	kempld_release_mutex(pld);
279
280	if (pretimeout)
281	wdt_data->pretimeout = timeout;
282	else
283	wdt_data->pretimeout = 0;
284
285	wdt_data->wdd.timeout = pretimeout + timeout;
286	}
287
288	static int kempld_wdt_start(struct watchdog_device *wdd)
289	{
290	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
291	struct kempld_device_data *pld = wdt_data->pld;
292	u8 status;
293	int ret;
294
295	ret = kempld_wdt_set_timeout(wdd, wdd->timeout);
296	if (ret)
297	return ret;
298
299	kempld_get_mutex(pld);
300	status = kempld_read8(pld, KEMPLD_WDT_CFG);
301	status \|= KEMPLD_WDT_CFG_ENABLE;
302	kempld_write8(pld, KEMPLD_WDT_CFG, status);
303	status = kempld_read8(pld, KEMPLD_WDT_CFG);
304	kempld_release_mutex(pld);
305
306	/* Check if the watchdog was enabled */
307	if (!(status & KEMPLD_WDT_CFG_ENABLE))
308	return -EACCES;
309
310	return 0;
311	}
312
313	static int kempld_wdt_stop(struct watchdog_device *wdd)
314	{
315	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
316	struct kempld_device_data *pld = wdt_data->pld;
317	u8 status;
318
319	kempld_get_mutex(pld);
320	status = kempld_read8(pld, KEMPLD_WDT_CFG);
321	status &= ~KEMPLD_WDT_CFG_ENABLE;
322	kempld_write8(pld, KEMPLD_WDT_CFG, status);
323	status = kempld_read8(pld, KEMPLD_WDT_CFG);
324	kempld_release_mutex(pld);
325
326	/* Check if the watchdog was disabled */
327	if (status & KEMPLD_WDT_CFG_ENABLE)
328	return -EACCES;
329
330	return 0;
331	}
332
333	static int kempld_wdt_keepalive(struct watchdog_device *wdd)
334	{
335	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
336	struct kempld_device_data *pld = wdt_data->pld;
337
338	kempld_get_mutex(pld);
339	kempld_write8(pld, KEMPLD_WDT_KICK, 'K');
340	kempld_release_mutex(pld);
341
342	return 0;
343	}
344
345	static long kempld_wdt_ioctl(struct watchdog_device *wdd, unsigned int cmd,
346	unsigned long arg)
347	{
348	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
349	void __user argp = (void __user )arg;
350	int ret = -ENOIOCTLCMD;
351	int __user *p = argp;
352	int new_value;
353
354	switch (cmd) {
355	case WDIOC_SETPRETIMEOUT:
356	if (get_user(new_value, p))
357	return -EFAULT;
358	ret = kempld_wdt_set_pretimeout(wdd, new_value);
359	if (ret)
360	return ret;
361	ret = kempld_wdt_keepalive(wdd);
362	break;
363	case WDIOC_GETPRETIMEOUT:
364	ret = put_user(wdt_data->pretimeout, (int *)arg);
365	break;
366	}
367
368	return ret;
369	}
370
371	static int kempld_wdt_probe_stages(struct watchdog_device *wdd)
372	{
373	struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
374	struct kempld_device_data *pld = wdt_data->pld;
375	struct kempld_wdt_stage *pretimeout_stage;
376	struct kempld_wdt_stage *timeout_stage;
377	u8 index, data, data_orig;
378	u32 mask;
379	int i, j;
380
381	pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
382	timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
383
384	pretimeout_stage->mask = 0;
385	timeout_stage->mask = 0;
386
387	for (i = 0; i < 3; i++) {
388	index = KEMPLD_WDT_STAGE_TIMEOUT(i);
389	mask = 0;
390
391	kempld_get_mutex(pld);
392	/* Probe each byte individually. */
393	for (j = 0; j < 4; j++) {
394	data_orig = kempld_read8(pld, index + j);
395	kempld_write8(pld, index + j, 0x00);
396	data = kempld_read8(pld, index + j);
397	/* A failed write means this byte is reserved */
398	if (data != 0x00)
399	break;
400	kempld_write8(pld, index + j, data_orig);
401	mask \|= 0xff << (j * 8);
402	}
403	kempld_release_mutex(pld);
404
405	/* Assign available stages to timeout and pretimeout */
406	if (!timeout_stage->mask) {
407	timeout_stage->mask = mask;
408	timeout_stage->id = i;
409	} else {
410	if (pld->feature_mask & KEMPLD_FEATURE_BIT_NMI) {
411	pretimeout_stage->mask = timeout_stage->mask;
412	timeout_stage->mask = mask;
413	pretimeout_stage->id = timeout_stage->id;
414	timeout_stage->id = i;
415	}
416	break;
417	}
418	}
419
420	if (!timeout_stage->mask)
421	return -ENODEV;
422
423	return 0;
424	}
425
426	static struct watchdog_info kempld_wdt_info = {
427	.identity = "KEMPLD Watchdog",
428	.options = WDIOF_SETTIMEOUT \|
429	WDIOF_KEEPALIVEPING \|
430	WDIOF_MAGICCLOSE \|
431	WDIOF_PRETIMEOUT
432	};
433
434	static struct watchdog_ops kempld_wdt_ops = {
435	.owner = THIS_MODULE,
436	.start = kempld_wdt_start,
437	.stop = kempld_wdt_stop,
438	.ping = kempld_wdt_keepalive,
439	.set_timeout = kempld_wdt_set_timeout,
440	.ioctl = kempld_wdt_ioctl,
441	};
442
443	static int kempld_wdt_probe(struct platform_device *pdev)
444	{
445	struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent);
446	struct kempld_wdt_data *wdt_data;
447	struct device *dev = &pdev->dev;
448	struct watchdog_device *wdd;
449	u8 status;
450	int ret = 0;
451
452	wdt_data = devm_kzalloc(dev, sizeof(*wdt_data), GFP_KERNEL);
453	if (!wdt_data)
454	return -ENOMEM;
455
456	wdt_data->pld = pld;
457	wdd = &wdt_data->wdd;
458	wdd->parent = dev;
459
460	kempld_get_mutex(pld);
461	status = kempld_read8(pld, KEMPLD_WDT_CFG);
462	kempld_release_mutex(pld);
463
464	/* Enable nowayout if watchdog is already locked */
465	if (status & (KEMPLD_WDT_CFG_ENABLE_LOCK \|
466	KEMPLD_WDT_CFG_GLOBAL_LOCK)) {
467	if (!nowayout)
468	dev_warn(dev,
469	"Forcing nowayout - watchdog lock enabled!\n");
470	nowayout = true;
471	}
472
473	wdd->info = &kempld_wdt_info;
474	wdd->ops = &kempld_wdt_ops;
475
476	watchdog_set_drvdata(wdd, wdt_data);
477	watchdog_set_nowayout(wdd, nowayout);
478
479	ret = kempld_wdt_probe_stages(wdd);
480	if (ret)
481	return ret;
482
483	kempld_wdt_set_timeout(wdd, timeout);
484	kempld_wdt_set_pretimeout(wdd, pretimeout);
485
486	/* Check if watchdog is already enabled */
487	if (status & KEMPLD_WDT_CFG_ENABLE) {
488	/* Get current watchdog settings */
489	kempld_wdt_update_timeouts(wdt_data);
490	dev_info(dev, "Watchdog was already enabled\n");
491	}
492
493	platform_set_drvdata(pdev, wdt_data);
494	ret = watchdog_register_device(wdd);
495	if (ret)
496	return ret;
497
498	dev_info(dev, "Watchdog registered with %ds timeout\n", wdd->timeout);
499
500	return 0;
501	}
502
503	static void kempld_wdt_shutdown(struct platform_device *pdev)
504	{
505	struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
506
507	kempld_wdt_stop(&wdt_data->wdd);
508	}
509
510	static int kempld_wdt_remove(struct platform_device *pdev)
511	{
512	struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
513	struct watchdog_device *wdd = &wdt_data->wdd;
514	int ret = 0;
515
516	if (!nowayout)
517	ret = kempld_wdt_stop(wdd);
518	watchdog_unregister_device(wdd);
519
520	return ret;
521	}
522
523	#ifdef CONFIG_PM
524	/* Disable watchdog if it is active during suspend */
525	static int kempld_wdt_suspend(struct platform_device *pdev,
526	pm_message_t message)
527	{
528	struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
529	struct kempld_device_data *pld = wdt_data->pld;
530	struct watchdog_device *wdd = &wdt_data->wdd;
531
532	kempld_get_mutex(pld);
533	wdt_data->pm_status_store = kempld_read8(pld, KEMPLD_WDT_CFG);
534	kempld_release_mutex(pld);
535
536	kempld_wdt_update_timeouts(wdt_data);
537
538	if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
539	return kempld_wdt_stop(wdd);
540
541	return 0;
542	}
543
544	/* Enable watchdog and configure it if necessary */
545	static int kempld_wdt_resume(struct platform_device *pdev)
546	{
547	struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
548	struct watchdog_device *wdd = &wdt_data->wdd;
549
550	/*
551	* If watchdog was stopped before suspend be sure it gets disabled
552	* again, for the case BIOS has enabled it during resume
553	*/
554	if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
555	return kempld_wdt_start(wdd);
556	else
557	return kempld_wdt_stop(wdd);
558	}
559	#else
560	#define kempld_wdt_suspend NULL
561	#define kempld_wdt_resume NULL
562	#endif
563
564	static struct platform_driver kempld_wdt_driver = {
565	.driver = {
566	.name = "kempld-wdt",
567	.owner = THIS_MODULE,
568	},
569	.probe = kempld_wdt_probe,
570	.remove = kempld_wdt_remove,
571	.shutdown = kempld_wdt_shutdown,
572	.suspend = kempld_wdt_suspend,
573	.resume = kempld_wdt_resume,
574	};
575
576	module_platform_driver(kempld_wdt_driver);
577
578	MODULE_DESCRIPTION("KEM PLD Watchdog Driver");
579	MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
580	MODULE_LICENSE("GPL");
581	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);