[mirror_ubuntu-bionic-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,
			     unsigned long action, void *data)
{
	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,meson8-wdt", .data = &meson6_wdt_data },
	{ .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data },
	{ .compatible = "amlogic,meson8m2-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);

	watchdog_stop_on_reboot(&meson_wdt->wdt_dev);
	err = devm_watchdog_register_device(&pdev->dev, &meson_wdt->wdt_dev);
	if (err)
		return err;

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

	return 0;
}

static struct platform_driver meson_wdt_driver = {
	.probe		= meson_wdt_probe,
	.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
4d8b229d GR	65	static int meson_wdt_restart(struct watchdog_device *wdt_dev,
4d8b229d GR	66	unsigned long action, void *data)
22e1b8f6	67	{
1b6fd59a	68	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
943bf1f6 CC	69	u32 tc_reboot = MESON_WDT_DC_RESET;
	70
	71	tc_reboot \|= meson_wdt->data->enable;
22e1b8f6 CC	72
	73	while (1) {
	74	writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
	75	mdelay(5);
	76	}
	77
1b6fd59a	78	return 0;
22e1b8f6 CC	79	}
	80
	81	static int meson_wdt_ping(struct watchdog_device *wdt_dev)
	82	{
	83	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	84
	85	writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
	86
	87	return 0;
	88	}
	89
	90	static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
	91	unsigned int timeout)
	92	{
	93	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	94	u32 reg;
	95
	96	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
943bf1f6 CC	97	reg &= ~meson_wdt->data->terminal_count_mask;
943bf1f6 CC	98	reg \|= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit);
22e1b8f6 CC	99	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
	100	}
	101
	102	static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
	103	unsigned int timeout)
	104	{
	105	wdt_dev->timeout = timeout;
	106
	107	meson_wdt_change_timeout(wdt_dev, timeout);
	108	meson_wdt_ping(wdt_dev);
	109
	110	return 0;
	111	}
	112
	113	static int meson_wdt_stop(struct watchdog_device *wdt_dev)
	114	{
	115	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	116	u32 reg;
	117
	118	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
943bf1f6	119	reg &= ~meson_wdt->data->enable;
22e1b8f6 CC	120	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
	121
	122	return 0;
	123	}
	124
	125	static int meson_wdt_start(struct watchdog_device *wdt_dev)
	126	{
	127	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
	128	u32 reg;
	129
	130	meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
	131	meson_wdt_ping(wdt_dev);
	132
	133	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
943bf1f6	134	reg \|= meson_wdt->data->enable;
22e1b8f6 CC	135	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
	136
	137	return 0;
	138	}
	139
	140	static const struct watchdog_info meson_wdt_info = {
	141	.identity = DRV_NAME,
	142	.options = WDIOF_SETTIMEOUT \|
	143	WDIOF_KEEPALIVEPING \|
	144	WDIOF_MAGICCLOSE,
	145	};
	146
	147	static const struct watchdog_ops meson_wdt_ops = {
	148	.owner = THIS_MODULE,
	149	.start = meson_wdt_start,
	150	.stop = meson_wdt_stop,
	151	.ping = meson_wdt_ping,
	152	.set_timeout = meson_wdt_set_timeout,
1b6fd59a	153	.restart = meson_wdt_restart,
22e1b8f6 CC	154	};
22e1b8f6 CC	155
943bf1f6 CC	156	static const struct of_device_id meson_wdt_dt_ids[] = {
943bf1f6 CC	157	{ .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data },
43a64e81	158	{ .compatible = "amlogic,meson8-wdt", .data = &meson6_wdt_data },
71388840	159	{ .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data },
43a64e81	160	{ .compatible = "amlogic,meson8m2-wdt", .data = &meson8b_wdt_data },
943bf1f6 CC	161	{ /* sentinel */ }
	162	};
	163	MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
	164
22e1b8f6 CC	165	static int meson_wdt_probe(struct platform_device *pdev)
	166	{
	167	struct resource *res;
	168	struct meson_wdt_dev *meson_wdt;
943bf1f6	169	const struct of_device_id *of_id;
22e1b8f6 CC	170	int err;
	171
	172	meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
	173	if (!meson_wdt)
	174	return -ENOMEM;
	175
	176	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	177	meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
	178	if (IS_ERR(meson_wdt->wdt_base))
	179	return PTR_ERR(meson_wdt->wdt_base);
	180
943bf1f6 CC	181	of_id = of_match_device(meson_wdt_dt_ids, &pdev->dev);
	182	if (!of_id) {
	183	dev_err(&pdev->dev, "Unable to initialize WDT data\n");
	184	return -ENODEV;
	185	}
	186	meson_wdt->data = of_id->data;
	187
22e1b8f6 CC	188	meson_wdt->wdt_dev.parent = &pdev->dev;
	189	meson_wdt->wdt_dev.info = &meson_wdt_info;
	190	meson_wdt->wdt_dev.ops = &meson_wdt_ops;
943bf1f6 CC	191	meson_wdt->wdt_dev.max_timeout =
943bf1f6 CC	192	meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit;
22e1b8f6	193	meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
943bf1f6 CC	194	meson_wdt->wdt_dev.timeout = min_t(unsigned int,
	195	MESON_WDT_TIMEOUT,
	196	meson_wdt->wdt_dev.max_timeout);
22e1b8f6 CC	197
	198	watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
	199
	200	watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev);
	201	watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
1b6fd59a	202	watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128);
22e1b8f6 CC	203
	204	meson_wdt_stop(&meson_wdt->wdt_dev);
	205
c8841a60 GR	206	watchdog_stop_on_reboot(&meson_wdt->wdt_dev);
c8841a60 GR	207	err = devm_watchdog_register_device(&pdev->dev, &meson_wdt->wdt_dev);
22e1b8f6 CC	208	if (err)
	209	return err;
	210
22e1b8f6 CC	211	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
	212	meson_wdt->wdt_dev.timeout, nowayout);
	213
	214	return 0;
	215	}
	216
22e1b8f6 CC	217	static struct platform_driver meson_wdt_driver = {
22e1b8f6 CC	218	.probe = meson_wdt_probe,
22e1b8f6	219	.driver = {
22e1b8f6 CC	220	.name = DRV_NAME,
	221	.of_match_table = meson_wdt_dt_ids,
	222	},
	223	};
	224
	225	module_platform_driver(meson_wdt_driver);
	226
	227	module_param(timeout, uint, 0);
	228	MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
	229
	230	module_param(nowayout, bool, 0);
	231	MODULE_PARM_DESC(nowayout,
	232	"Watchdog cannot be stopped once started (default="
	233	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	234
	235	MODULE_LICENSE("GPL");
	236	MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
	237	MODULE_DESCRIPTION("Meson Watchdog Timer Driver");