[mirror_ubuntu-hirsute-kernel.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/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>

#define DRV_NAME		"meson_wdt"

#define MESON_WDT_TC		0x00
#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_SEC_TO_TC(s, c)	((s) * (c))

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

struct meson_wdt_data {
	unsigned int enable;
	unsigned int terminal_count_mask;
	unsigned int count_unit;
};

static struct meson_wdt_data meson6_wdt_data = {
	.enable			= BIT(22),
	.terminal_count_mask	= 0x3fffff,
	.count_unit		= 100000, /* 10 us */
};

static struct meson_wdt_data meson8b_wdt_data = {
	.enable			= BIT(19),
	.terminal_count_mask	= 0xffff,
	.count_unit		= 7812, /* 128 us */
};

struct meson_wdt_dev {
	struct watchdog_device wdt_dev;
	void __iomem *wdt_base;
	const struct meson_wdt_data *data;
};

static int meson_wdt_restart(struct watchdog_device *wdt_dev)
{
	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	u32 tc_reboot = MESON_WDT_DC_RESET;

	tc_reboot |= meson_wdt->data->enable;

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

	return 0;
}

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->data->terminal_count_mask;
	reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit);
	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->data->enable;
	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->data->enable;
	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,
	.restart        = meson_wdt_restart,
};

static const struct of_device_id meson_wdt_dt_ids[] = {
	{ .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data },
	{ .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);

static int meson_wdt_probe(struct platform_device *pdev)
{
	struct resource *res;
	struct meson_wdt_dev *meson_wdt;
	const struct of_device_id *of_id;
	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);

	of_id = of_match_device(meson_wdt_dt_ids, &pdev->dev);
	if (!of_id) {
		dev_err(&pdev->dev, "Unable to initialize WDT data\n");
		return -ENODEV;
	}
	meson_wdt->data = of_id->data;

	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.max_timeout =
		meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit;
	meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
	meson_wdt->wdt_dev.timeout = min_t(unsigned int,
					   MESON_WDT_TIMEOUT,
					   meson_wdt->wdt_dev.max_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);
	watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128);

	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);

	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);

	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 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>
22e1b8f6	20	#include <linux/of.h>
943bf1f6	21	#include <linux/of_device.h>
22e1b8f6	22	#include <linux/platform_device.h>
22e1b8f6 CC	23	#include <linux/types.h>
	24	#include <linux/watchdog.h>
	25
	26	#define DRV_NAME "meson_wdt"
	27
	28	#define MESON_WDT_TC 0x00
22e1b8f6 CC	29	#define MESON_WDT_DC_RESET (3 << 24)
	30
	31	#define MESON_WDT_RESET 0x04
	32
	33	#define MESON_WDT_TIMEOUT 30
	34	#define MESON_WDT_MIN_TIMEOUT 1
22e1b8f6	35
943bf1f6	36	#define MESON_SEC_TO_TC(s, c) ((s) * (c))
22e1b8f6 CC	37
	38	static bool nowayout = WATCHDOG_NOWAYOUT;
	39	static unsigned int timeout = MESON_WDT_TIMEOUT;
	40
943bf1f6 CC	41	struct meson_wdt_data {
	42	unsigned int enable;
	43	unsigned int terminal_count_mask;
	44	unsigned int count_unit;
	45	};
	46
	47	static struct meson_wdt_data meson6_wdt_data = {
	48	.enable = BIT(22),
	49	.terminal_count_mask = 0x3fffff,
	50	.count_unit = 100000, /* 10 us */
	51	};
	52
71388840 CC	53	static struct meson_wdt_data meson8b_wdt_data = {
	54	.enable = BIT(19),
	55	.terminal_count_mask = 0xffff,
	56	.count_unit = 7812, /* 128 us */
	57	};
	58
22e1b8f6 CC	59	struct meson_wdt_dev {
	60	struct watchdog_device wdt_dev;
	61	void __iomem *wdt_base;
943bf1f6	62	const struct meson_wdt_data *data;
22e1b8f6 CC	63	};
22e1b8f6 CC	64
1b6fd59a	65	static int meson_wdt_restart(struct watchdog_device *wdt_dev)
22e1b8f6	66	{
1b6fd59a	67	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
943bf1f6 CC	68	u32 tc_reboot = MESON_WDT_DC_RESET;
	69
	70	tc_reboot \|= meson_wdt->data->enable;
22e1b8f6 CC	71
	72	while (1) {
	73	writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
	74	mdelay(5);
	75	}
	76
1b6fd59a	77	return 0;
22e1b8f6 CC	78	}
	79
	80	static int meson_wdt_ping(struct watchdog_device *wdt_dev)
	81	{
	82	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	83
	84	writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
	85
	86	return 0;
	87	}
	88
	89	static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
	90	unsigned int timeout)
	91	{
	92	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	93	u32 reg;
	94
	95	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
943bf1f6 CC	96	reg &= ~meson_wdt->data->terminal_count_mask;
943bf1f6 CC	97	reg \|= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit);
22e1b8f6 CC	98	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
	99	}
	100
	101	static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
	102	unsigned int timeout)
	103	{
	104	wdt_dev->timeout = timeout;
	105
	106	meson_wdt_change_timeout(wdt_dev, timeout);
	107	meson_wdt_ping(wdt_dev);
	108
	109	return 0;
	110	}
	111
	112	static int meson_wdt_stop(struct watchdog_device *wdt_dev)
	113	{
	114	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	115	u32 reg;
	116
	117	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
943bf1f6	118	reg &= ~meson_wdt->data->enable;
22e1b8f6 CC	119	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
	120
	121	return 0;
	122	}
	123
	124	static int meson_wdt_start(struct watchdog_device *wdt_dev)
	125	{
	126	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	127	u32 reg;
	128
	129	meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
	130	meson_wdt_ping(wdt_dev);
	131
	132	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
943bf1f6	133	reg \|= meson_wdt->data->enable;
22e1b8f6 CC	134	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
	135
	136	return 0;
	137	}
	138
	139	static const struct watchdog_info meson_wdt_info = {
	140	.identity = DRV_NAME,
	141	.options = WDIOF_SETTIMEOUT \|
	142	WDIOF_KEEPALIVEPING \|
	143	WDIOF_MAGICCLOSE,
	144	};
	145
	146	static const struct watchdog_ops meson_wdt_ops = {
	147	.owner = THIS_MODULE,
	148	.start = meson_wdt_start,
	149	.stop = meson_wdt_stop,
	150	.ping = meson_wdt_ping,
	151	.set_timeout = meson_wdt_set_timeout,
1b6fd59a	152	.restart = meson_wdt_restart,
22e1b8f6 CC	153	};
22e1b8f6 CC	154
943bf1f6 CC	155	static const struct of_device_id meson_wdt_dt_ids[] = {
943bf1f6 CC	156	{ .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data },
71388840	157	{ .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data },
943bf1f6 CC	158	{ /* sentinel */ }
	159	};
	160	MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
	161
22e1b8f6 CC	162	static int meson_wdt_probe(struct platform_device *pdev)
	163	{
	164	struct resource *res;
	165	struct meson_wdt_dev *meson_wdt;
943bf1f6	166	const struct of_device_id *of_id;
22e1b8f6 CC	167	int err;
	168
	169	meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
	170	if (!meson_wdt)
	171	return -ENOMEM;
	172
	173	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	174	meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
	175	if (IS_ERR(meson_wdt->wdt_base))
	176	return PTR_ERR(meson_wdt->wdt_base);
	177
943bf1f6 CC	178	of_id = of_match_device(meson_wdt_dt_ids, &pdev->dev);
	179	if (!of_id) {
	180	dev_err(&pdev->dev, "Unable to initialize WDT data\n");
	181	return -ENODEV;
	182	}
	183	meson_wdt->data = of_id->data;
	184
22e1b8f6 CC	185	meson_wdt->wdt_dev.parent = &pdev->dev;
	186	meson_wdt->wdt_dev.info = &meson_wdt_info;
	187	meson_wdt->wdt_dev.ops = &meson_wdt_ops;
943bf1f6 CC	188	meson_wdt->wdt_dev.max_timeout =
943bf1f6 CC	189	meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit;
22e1b8f6	190	meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
943bf1f6 CC	191	meson_wdt->wdt_dev.timeout = min_t(unsigned int,
	192	MESON_WDT_TIMEOUT,
	193	meson_wdt->wdt_dev.max_timeout);
22e1b8f6 CC	194
	195	watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
	196
	197	watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev);
	198	watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
1b6fd59a	199	watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128);
22e1b8f6 CC	200
	201	meson_wdt_stop(&meson_wdt->wdt_dev);
	202
	203	err = watchdog_register_device(&meson_wdt->wdt_dev);
	204	if (err)
	205	return err;
	206
	207	platform_set_drvdata(pdev, meson_wdt);
	208
22e1b8f6 CC	209	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
	210	meson_wdt->wdt_dev.timeout, nowayout);
	211
	212	return 0;
	213	}
	214
	215	static int meson_wdt_remove(struct platform_device *pdev)
	216	{
	217	struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
	218
22e1b8f6 CC	219	watchdog_unregister_device(&meson_wdt->wdt_dev);
	220
	221	return 0;
	222	}
	223
	224	static void meson_wdt_shutdown(struct platform_device *pdev)
	225	{
	226	struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
	227
	228	meson_wdt_stop(&meson_wdt->wdt_dev);
	229	}
	230
22e1b8f6 CC	231	static struct platform_driver meson_wdt_driver = {
	232	.probe = meson_wdt_probe,
	233	.remove = meson_wdt_remove,
	234	.shutdown = meson_wdt_shutdown,
	235	.driver = {
22e1b8f6 CC	236	.name = DRV_NAME,
	237	.of_match_table = meson_wdt_dt_ids,
	238	},
	239	};
	240
	241	module_platform_driver(meson_wdt_driver);
	242
	243	module_param(timeout, uint, 0);
	244	MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
	245
	246	module_param(nowayout, bool, 0);
	247	MODULE_PARM_DESC(nowayout,
	248	"Watchdog cannot be stopped once started (default="
	249	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	250
	251	MODULE_LICENSE("GPL");
	252	MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
	253	MODULE_DESCRIPTION("Meson Watchdog Timer Driver");