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

/*
 *      Meson Watchdog Driver
 *
 *      Copyright (c) 2014 Carlo Caione
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/watchdog.h>

#define DRV_NAME		"meson_wdt"

#define MESON_WDT_TC		0x00
#define MESON_WDT_TC_EN		BIT(22)
#define MESON_WDT_TC_TM_MASK	0x3fffff
#define MESON_WDT_DC_RESET	(3 << 24)

#define MESON_WDT_RESET		0x04

#define MESON_WDT_TIMEOUT	30
#define MESON_WDT_MIN_TIMEOUT	1
#define MESON_WDT_MAX_TIMEOUT	(MESON_WDT_TC_TM_MASK / 100000)

#define MESON_SEC_TO_TC(s)	((s) * 100000)

static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int timeout = MESON_WDT_TIMEOUT;

struct meson_wdt_dev {
	struct watchdog_device wdt_dev;
	void __iomem *wdt_base;
	struct notifier_block restart_handler;
};

static int meson_restart_handle(struct notifier_block *this, unsigned long mode,
				void *cmd)
{
	u32 tc_reboot = MESON_WDT_DC_RESET | MESON_WDT_TC_EN;
	struct meson_wdt_dev *meson_wdt = container_of(this,
						       struct meson_wdt_dev,
						       restart_handler);

	while (1) {
		writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
		mdelay(5);
	}

	return NOTIFY_DONE;
}

static int meson_wdt_ping(struct watchdog_device *wdt_dev)
{
	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);

	writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);

	return 0;
}

static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
				     unsigned int timeout)
{
	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	u32 reg;

	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
	reg &= ~MESON_WDT_TC_TM_MASK;
	reg |= MESON_SEC_TO_TC(timeout);
	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
}

static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
				 unsigned int timeout)
{
	wdt_dev->timeout = timeout;

	meson_wdt_change_timeout(wdt_dev, timeout);
	meson_wdt_ping(wdt_dev);

	return 0;
}

static int meson_wdt_stop(struct watchdog_device *wdt_dev)
{
	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	u32 reg;

	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
	reg &= ~MESON_WDT_TC_EN;
	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);

	return 0;
}

static int meson_wdt_start(struct watchdog_device *wdt_dev)
{
	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	u32 reg;

	meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
	meson_wdt_ping(wdt_dev);

	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
	reg |= MESON_WDT_TC_EN;
	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);

	return 0;
}

static const struct watchdog_info meson_wdt_info = {
	.identity	= DRV_NAME,
	.options	= WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING |
			  WDIOF_MAGICCLOSE,
};

static const struct watchdog_ops meson_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= meson_wdt_start,
	.stop		= meson_wdt_stop,
	.ping		= meson_wdt_ping,
	.set_timeout	= meson_wdt_set_timeout,
};

static int meson_wdt_probe(struct platform_device *pdev)
{
	struct resource *res;
	struct meson_wdt_dev *meson_wdt;
	int err;

	meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
	if (!meson_wdt)
		return -ENOMEM;

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

	meson_wdt->wdt_dev.parent = &pdev->dev;
	meson_wdt->wdt_dev.info = &meson_wdt_info;
	meson_wdt->wdt_dev.ops = &meson_wdt_ops;
	meson_wdt->wdt_dev.timeout = MESON_WDT_TIMEOUT;
	meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT;
	meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;

	watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);

	watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev);
	watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);

	meson_wdt_stop(&meson_wdt->wdt_dev);

	err = watchdog_register_device(&meson_wdt->wdt_dev);
	if (err)
		return err;

	platform_set_drvdata(pdev, meson_wdt);

	meson_wdt->restart_handler.notifier_call = meson_restart_handle;
	meson_wdt->restart_handler.priority = 128;
	err = register_restart_handler(&meson_wdt->restart_handler);
	if (err)
		dev_err(&pdev->dev,
			"cannot register restart handler (err=%d)\n", err);

	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
		 meson_wdt->wdt_dev.timeout, nowayout);

	return 0;
}

static int meson_wdt_remove(struct platform_device *pdev)
{
	struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);

	unregister_restart_handler(&meson_wdt->restart_handler);

	watchdog_unregister_device(&meson_wdt->wdt_dev);

	return 0;
}

static void meson_wdt_shutdown(struct platform_device *pdev)
{
	struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);

	meson_wdt_stop(&meson_wdt->wdt_dev);
}

static const struct of_device_id meson_wdt_dt_ids[] = {
	{ .compatible = "amlogic,meson6-wdt" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);

static struct platform_driver meson_wdt_driver = {
	.probe		= meson_wdt_probe,
	.remove		= meson_wdt_remove,
	.shutdown	= meson_wdt_shutdown,
	.driver		= {
		.name		= DRV_NAME,
		.of_match_table	= meson_wdt_dt_ids,
	},
};

module_platform_driver(meson_wdt_driver);

module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");

module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
		 "Watchdog cannot be stopped once started (default="
		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
Commit	Line	Data
22e1b8f6 CC	1	/*
	2	* Meson Watchdog Driver
	3	*
	4	* Copyright (c) 2014 Carlo Caione
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/clk.h>
	13	#include <linux/delay.h>
	14	#include <linux/err.h>
	15	#include <linux/init.h>
	16	#include <linux/io.h>
	17	#include <linux/kernel.h>
	18	#include <linux/module.h>
	19	#include <linux/moduleparam.h>
	20	#include <linux/notifier.h>
	21	#include <linux/of.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/reboot.h>
	24	#include <linux/types.h>
	25	#include <linux/watchdog.h>
	26
	27	#define DRV_NAME "meson_wdt"
	28
	29	#define MESON_WDT_TC 0x00
	30	#define MESON_WDT_TC_EN BIT(22)
	31	#define MESON_WDT_TC_TM_MASK 0x3fffff
	32	#define MESON_WDT_DC_RESET (3 << 24)
	33
	34	#define MESON_WDT_RESET 0x04
	35
	36	#define MESON_WDT_TIMEOUT 30
	37	#define MESON_WDT_MIN_TIMEOUT 1
	38	#define MESON_WDT_MAX_TIMEOUT (MESON_WDT_TC_TM_MASK / 100000)
	39
	40	#define MESON_SEC_TO_TC(s) ((s) * 100000)
	41
	42	static bool nowayout = WATCHDOG_NOWAYOUT;
	43	static unsigned int timeout = MESON_WDT_TIMEOUT;
	44
	45	struct meson_wdt_dev {
	46	struct watchdog_device wdt_dev;
	47	void __iomem *wdt_base;
	48	struct notifier_block restart_handler;
	49	};
	50
	51	static int meson_restart_handle(struct notifier_block *this, unsigned long mode,
	52	void *cmd)
	53	{
06980b24	54	u32 tc_reboot = MESON_WDT_DC_RESET \| MESON_WDT_TC_EN;
22e1b8f6 CC	55	struct meson_wdt_dev *meson_wdt = container_of(this,
	56	struct meson_wdt_dev,
	57	restart_handler);
	58
	59	while (1) {
	60	writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
	61	mdelay(5);
	62	}
	63
	64	return NOTIFY_DONE;
	65	}
	66
	67	static int meson_wdt_ping(struct watchdog_device *wdt_dev)
	68	{
	69	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	70
	71	writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
	72
	73	return 0;
	74	}
	75
	76	static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
	77	unsigned int timeout)
	78	{
	79	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	80	u32 reg;
	81
	82	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
	83	reg &= ~MESON_WDT_TC_TM_MASK;
	84	reg \|= MESON_SEC_TO_TC(timeout);
	85	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
	86	}
	87
	88	static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
	89	unsigned int timeout)
	90	{
	91	wdt_dev->timeout = timeout;
	92
	93	meson_wdt_change_timeout(wdt_dev, timeout);
	94	meson_wdt_ping(wdt_dev);
	95
	96	return 0;
	97	}
	98
	99	static int meson_wdt_stop(struct watchdog_device *wdt_dev)
	100	{
	101	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	102	u32 reg;
	103
	104	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
	105	reg &= ~MESON_WDT_TC_EN;
	106	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
	107
	108	return 0;
	109	}
	110
	111	static int meson_wdt_start(struct watchdog_device *wdt_dev)
	112	{
	113	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	114	u32 reg;
	115
	116	meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
	117	meson_wdt_ping(wdt_dev);
	118
119	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
120	reg \|= MESON_WDT_TC_EN;
121	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
122
123	return 0;
124	}
125
126	static const struct watchdog_info meson_wdt_info = {
127	.identity = DRV_NAME,
128	.options = WDIOF_SETTIMEOUT \|
129	WDIOF_KEEPALIVEPING \|
130	WDIOF_MAGICCLOSE,
131	};
132
133	static const struct watchdog_ops meson_wdt_ops = {
134	.owner = THIS_MODULE,
135	.start = meson_wdt_start,
136	.stop = meson_wdt_stop,
137	.ping = meson_wdt_ping,
138	.set_timeout = meson_wdt_set_timeout,
139	};
140
141	static int meson_wdt_probe(struct platform_device *pdev)
142	{
143	struct resource *res;
144	struct meson_wdt_dev *meson_wdt;
145	int err;
146
147	meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
148	if (!meson_wdt)
149	return -ENOMEM;
150
151	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
152	meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
153	if (IS_ERR(meson_wdt->wdt_base))
154	return PTR_ERR(meson_wdt->wdt_base);
155
156	meson_wdt->wdt_dev.parent = &pdev->dev;
157	meson_wdt->wdt_dev.info = &meson_wdt_info;
158	meson_wdt->wdt_dev.ops = &meson_wdt_ops;
159	meson_wdt->wdt_dev.timeout = MESON_WDT_TIMEOUT;
160	meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT;
161	meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
162
163	watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
164
165	watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev);
166	watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
167
168	meson_wdt_stop(&meson_wdt->wdt_dev);
169
170	err = watchdog_register_device(&meson_wdt->wdt_dev);
171	if (err)
172	return err;
173
174	platform_set_drvdata(pdev, meson_wdt);
175
176	meson_wdt->restart_handler.notifier_call = meson_restart_handle;
177	meson_wdt->restart_handler.priority = 128;
178	err = register_restart_handler(&meson_wdt->restart_handler);
179	if (err)
180	dev_err(&pdev->dev,
181	"cannot register restart handler (err=%d)\n", err);
182
183	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
184	meson_wdt->wdt_dev.timeout, nowayout);
185
186	return 0;
187	}
188
189	static int meson_wdt_remove(struct platform_device *pdev)
190	{
191	struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
192
193	unregister_restart_handler(&meson_wdt->restart_handler);
194
195	watchdog_unregister_device(&meson_wdt->wdt_dev);
196
197	return 0;
198	}
199
200	static void meson_wdt_shutdown(struct platform_device *pdev)
201	{
202	struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
203
204	meson_wdt_stop(&meson_wdt->wdt_dev);
205	}
206
207	static const struct of_device_id meson_wdt_dt_ids[] = {
208	{ .compatible = "amlogic,meson6-wdt" },
209	{ /* sentinel */ }
210	};
211	MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
212
213	static struct platform_driver meson_wdt_driver = {
214	.probe = meson_wdt_probe,
215	.remove = meson_wdt_remove,
216	.shutdown = meson_wdt_shutdown,
217	.driver = {
22e1b8f6 CC	218	.name = DRV_NAME,
	219	.of_match_table = meson_wdt_dt_ids,
	220	},
	221	};
	222
	223	module_platform_driver(meson_wdt_driver);
	224
	225	module_param(timeout, uint, 0);
	226	MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
	227
	228	module_param(nowayout, bool, 0);
	229	MODULE_PARM_DESC(nowayout,
	230	"Watchdog cannot be stopped once started (default="
	231	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	232
	233	MODULE_LICENSE("GPL");
	234	MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
	235	MODULE_DESCRIPTION("Meson Watchdog Timer Driver");