[mirror_ubuntu-kernels.git] / drivers / watchdog / bcm7038_wdt.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2015 Broadcom Corporation
 *
 */

#include <linux/clk.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/watchdog.h>

#define WDT_START_1		0xff00
#define WDT_START_2		0x00ff
#define WDT_STOP_1		0xee00
#define WDT_STOP_2		0x00ee

#define WDT_TIMEOUT_REG		0x0
#define WDT_CMD_REG		0x4

#define WDT_MIN_TIMEOUT		1 /* seconds */
#define WDT_DEFAULT_TIMEOUT	30 /* seconds */
#define WDT_DEFAULT_RATE	27000000

struct bcm7038_watchdog {
	void __iomem		*base;
	struct watchdog_device	wdd;
	u32			rate;
	struct clk		*clk;
};

static bool nowayout = WATCHDOG_NOWAYOUT;

static inline void bcm7038_wdt_write(u32 value, void __iomem *addr)
{
	/* MIPS chips strapped for BE will automagically configure the
	 * peripheral registers for CPU-native byte order.
	 */
	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
		__raw_writel(value, addr);
	else
		writel_relaxed(value, addr);
}

static inline u32 bcm7038_wdt_read(void __iomem *addr)
{
	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
		return __raw_readl(addr);
	else
		return readl_relaxed(addr);
}

static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
{
	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	u32 timeout;

	timeout = wdt->rate * wdog->timeout;

	bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG);
}

static int bcm7038_wdt_ping(struct watchdog_device *wdog)
{
	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);

	bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG);
	bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG);

	return 0;
}

static int bcm7038_wdt_start(struct watchdog_device *wdog)
{
	bcm7038_wdt_set_timeout_reg(wdog);
	bcm7038_wdt_ping(wdog);

	return 0;
}

static int bcm7038_wdt_stop(struct watchdog_device *wdog)
{
	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);

	bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG);
	bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG);

	return 0;
}

static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog,
				   unsigned int t)
{
	/* Can't modify timeout value if watchdog timer is running */
	bcm7038_wdt_stop(wdog);
	wdog->timeout = t;
	bcm7038_wdt_start(wdog);

	return 0;
}

static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)
{
	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	u32 time_left;

	time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG);

	return time_left / wdt->rate;
}

static const struct watchdog_info bcm7038_wdt_info = {
	.identity	= "Broadcom BCM7038 Watchdog Timer",
	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
				WDIOF_MAGICCLOSE
};

static const struct watchdog_ops bcm7038_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= bcm7038_wdt_start,
	.stop		= bcm7038_wdt_stop,
	.set_timeout	= bcm7038_wdt_set_timeout,
	.get_timeleft	= bcm7038_wdt_get_timeleft,
};

static void bcm7038_clk_disable_unprepare(void *data)
{
	clk_disable_unprepare(data);
}

static int bcm7038_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct bcm7038_watchdog *wdt;
	int err;

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

	platform_set_drvdata(pdev, wdt);

	wdt->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(wdt->base))
		return PTR_ERR(wdt->base);

	wdt->clk = devm_clk_get(dev, NULL);
	/* If unable to get clock, use default frequency */
	if (!IS_ERR(wdt->clk)) {
		err = clk_prepare_enable(wdt->clk);
		if (err)
			return err;
		err = devm_add_action_or_reset(dev,
					       bcm7038_clk_disable_unprepare,
					       wdt->clk);
		if (err)
			return err;
		wdt->rate = clk_get_rate(wdt->clk);
		/* Prevent divide-by-zero exception */
		if (!wdt->rate)
			wdt->rate = WDT_DEFAULT_RATE;
	} else {
		wdt->rate = WDT_DEFAULT_RATE;
		wdt->clk = NULL;
	}

	wdt->wdd.info		= &bcm7038_wdt_info;
	wdt->wdd.ops		= &bcm7038_wdt_ops;
	wdt->wdd.min_timeout	= WDT_MIN_TIMEOUT;
	wdt->wdd.timeout	= WDT_DEFAULT_TIMEOUT;
	wdt->wdd.max_timeout	= 0xffffffff / wdt->rate;
	wdt->wdd.parent		= dev;
	watchdog_set_drvdata(&wdt->wdd, wdt);

	watchdog_stop_on_reboot(&wdt->wdd);
	watchdog_stop_on_unregister(&wdt->wdd);
	err = devm_watchdog_register_device(dev, &wdt->wdd);
	if (err)
		return err;

	dev_info(dev, "Registered BCM7038 Watchdog\n");

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int bcm7038_wdt_suspend(struct device *dev)
{
	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);

	if (watchdog_active(&wdt->wdd))
		return bcm7038_wdt_stop(&wdt->wdd);

	return 0;
}

static int bcm7038_wdt_resume(struct device *dev)
{
	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);

	if (watchdog_active(&wdt->wdd))
		return bcm7038_wdt_start(&wdt->wdd);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend,
			 bcm7038_wdt_resume);

static const struct of_device_id bcm7038_wdt_match[] = {
	{ .compatible = "brcm,bcm7038-wdt" },
	{},
};
MODULE_DEVICE_TABLE(of, bcm7038_wdt_match);

static struct platform_driver bcm7038_wdt_driver = {
	.probe		= bcm7038_wdt_probe,
	.driver		= {
		.name		= "bcm7038-wdt",
		.of_match_table	= bcm7038_wdt_match,
		.pm		= &bcm7038_wdt_pm_ops,
	}
};
module_platform_driver(bcm7038_wdt_driver);

module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
MODULE_AUTHOR("Justin Chen");
Commit	Line	Data
2e62c498	1	// SPDX-License-Identifier: GPL-2.0+
7a3629fe JC	2	/*
	3	* Copyright (C) 2015 Broadcom Corporation
	4	*
7a3629fe JC	5	*/
	6
	7	#include <linux/clk.h>
	8	#include <linux/init.h>
	9	#include <linux/io.h>
	10	#include <linux/module.h>
	11	#include <linux/of.h>
	12	#include <linux/platform_device.h>
	13	#include <linux/pm.h>
	14	#include <linux/watchdog.h>
	15
	16	#define WDT_START_1 0xff00
	17	#define WDT_START_2 0x00ff
	18	#define WDT_STOP_1 0xee00
	19	#define WDT_STOP_2 0x00ee
	20
	21	#define WDT_TIMEOUT_REG 0x0
	22	#define WDT_CMD_REG 0x4
	23
	24	#define WDT_MIN_TIMEOUT 1 /* seconds */
	25	#define WDT_DEFAULT_TIMEOUT 30 /* seconds */
	26	#define WDT_DEFAULT_RATE 27000000
	27
	28	struct bcm7038_watchdog {
	29	void __iomem *base;
	30	struct watchdog_device wdd;
	31	u32 rate;
	32	struct clk *clk;
	33	};
	34
	35	static bool nowayout = WATCHDOG_NOWAYOUT;
	36
e379c219 ÁFR	37	static inline void bcm7038_wdt_write(u32 value, void __iomem *addr)
	38	{
	39	/* MIPS chips strapped for BE will automagically configure the
	40	* peripheral registers for CPU-native byte order.
	41	*/
	42	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
	43	__raw_writel(value, addr);
	44	else
	45	writel_relaxed(value, addr);
	46	}
	47
	48	static inline u32 bcm7038_wdt_read(void __iomem *addr)
	49	{
	50	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
	51	return __raw_readl(addr);
	52	else
	53	return readl_relaxed(addr);
	54	}
	55
7a3629fe JC	56	static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
	57	{
	58	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	59	u32 timeout;
	60
	61	timeout = wdt->rate * wdog->timeout;
	62
e379c219	63	bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG);
7a3629fe JC	64	}
	65
	66	static int bcm7038_wdt_ping(struct watchdog_device *wdog)
	67	{
	68	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	69
e379c219 ÁFR	70	bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG);
e379c219 ÁFR	71	bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG);
7a3629fe JC	72
	73	return 0;
	74	}
	75
	76	static int bcm7038_wdt_start(struct watchdog_device *wdog)
	77	{
	78	bcm7038_wdt_set_timeout_reg(wdog);
	79	bcm7038_wdt_ping(wdog);
	80
	81	return 0;
	82	}
	83
	84	static int bcm7038_wdt_stop(struct watchdog_device *wdog)
	85	{
	86	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	87
e379c219 ÁFR	88	bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG);
e379c219 ÁFR	89	bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG);
7a3629fe JC	90
	91	return 0;
	92	}
	93
	94	static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog,
	95	unsigned int t)
	96	{
	97	/* Can't modify timeout value if watchdog timer is running */
	98	bcm7038_wdt_stop(wdog);
	99	wdog->timeout = t;
	100	bcm7038_wdt_start(wdog);
	101
	102	return 0;
	103	}
	104
	105	static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)
	106	{
	107	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	108	u32 time_left;
	109
e379c219	110	time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG);
7a3629fe JC	111
	112	return time_left / wdt->rate;
	113	}
	114
6c368932	115	static const struct watchdog_info bcm7038_wdt_info = {
7a3629fe JC	116	.identity = "Broadcom BCM7038 Watchdog Timer",
	117	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
	118	WDIOF_MAGICCLOSE
	119	};
	120
85f15cfc	121	static const struct watchdog_ops bcm7038_wdt_ops = {
7a3629fe JC	122	.owner = THIS_MODULE,
	123	.start = bcm7038_wdt_start,
	124	.stop = bcm7038_wdt_stop,
	125	.set_timeout = bcm7038_wdt_set_timeout,
	126	.get_timeleft = bcm7038_wdt_get_timeleft,
	127	};
	128
69656dcd GR	129	static void bcm7038_clk_disable_unprepare(void *data)
	130	{
	131	clk_disable_unprepare(data);
	132	}
	133
7a3629fe JC	134	static int bcm7038_wdt_probe(struct platform_device *pdev)
	135	{
	136	struct device *dev = &pdev->dev;
	137	struct bcm7038_watchdog *wdt;
7a3629fe JC	138	int err;
	139
	140	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
	141	if (!wdt)
	142	return -ENOMEM;
	143
	144	platform_set_drvdata(pdev, wdt);
	145
0f0a6a28	146	wdt->base = devm_platform_ioremap_resource(pdev, 0);
7a3629fe JC	147	if (IS_ERR(wdt->base))
	148	return PTR_ERR(wdt->base);
	149
	150	wdt->clk = devm_clk_get(dev, NULL);
	151	/* If unable to get clock, use default frequency */
	152	if (!IS_ERR(wdt->clk)) {
dd0a18ca	153	err = clk_prepare_enable(wdt->clk);
69656dcd GR	154	if (err)
	155	return err;
	156	err = devm_add_action_or_reset(dev,
	157	bcm7038_clk_disable_unprepare,
	158	wdt->clk);
dd0a18ca FE	159	if (err)
dd0a18ca FE	160	return err;
7a3629fe JC	161	wdt->rate = clk_get_rate(wdt->clk);
	162	/* Prevent divide-by-zero exception */
	163	if (!wdt->rate)
	164	wdt->rate = WDT_DEFAULT_RATE;
	165	} else {
	166	wdt->rate = WDT_DEFAULT_RATE;
	167	wdt->clk = NULL;
	168	}
	169
	170	wdt->wdd.info = &bcm7038_wdt_info;
	171	wdt->wdd.ops = &bcm7038_wdt_ops;
	172	wdt->wdd.min_timeout = WDT_MIN_TIMEOUT;
	173	wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
	174	wdt->wdd.max_timeout = 0xffffffff / wdt->rate;
	175	wdt->wdd.parent = dev;
	176	watchdog_set_drvdata(&wdt->wdd, wdt);
	177
69656dcd GR	178	watchdog_stop_on_reboot(&wdt->wdd);
	179	watchdog_stop_on_unregister(&wdt->wdd);
	180	err = devm_watchdog_register_device(dev, &wdt->wdd);
f5429895	181	if (err)
7a3629fe	182	return err;
7a3629fe JC	183
	184	dev_info(dev, "Registered BCM7038 Watchdog\n");
	185
	186	return 0;
	187	}
	188
7a3629fe JC	189	#ifdef CONFIG_PM_SLEEP
	190	static int bcm7038_wdt_suspend(struct device *dev)
	191	{
	192	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
	193
	194	if (watchdog_active(&wdt->wdd))
	195	return bcm7038_wdt_stop(&wdt->wdd);
	196
	197	return 0;
	198	}
	199
	200	static int bcm7038_wdt_resume(struct device *dev)
	201	{
	202	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
	203
	204	if (watchdog_active(&wdt->wdd))
	205	return bcm7038_wdt_start(&wdt->wdd);
	206
	207	return 0;
	208	}
	209	#endif
	210
	211	static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend,
	212	bcm7038_wdt_resume);
	213
7a3629fe JC	214	static const struct of_device_id bcm7038_wdt_match[] = {
	215	{ .compatible = "brcm,bcm7038-wdt" },
	216	{},
	217	};
57d77c62	218	MODULE_DEVICE_TABLE(of, bcm7038_wdt_match);
7a3629fe JC	219
	220	static struct platform_driver bcm7038_wdt_driver = {
	221	.probe = bcm7038_wdt_probe,
7a3629fe JC	222	.driver = {
	223	.name = "bcm7038-wdt",
	224	.of_match_table = bcm7038_wdt_match,
	225	.pm = &bcm7038_wdt_pm_ops,
	226	}
	227	};
	228	module_platform_driver(bcm7038_wdt_driver);
	229
	230	module_param(nowayout, bool, 0);
	231	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	232	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
2e62c498	233	MODULE_LICENSE("GPL");
7a3629fe JC	234	MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
7a3629fe JC	235	MODULE_AUTHOR("Justin Chen");