[linux-2.6-block.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 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;

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

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

	writel(WDT_START_1, wdt->base + WDT_CMD_REG);
	writel(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);

	writel(WDT_STOP_1, wdt->base + WDT_CMD_REG);
	writel(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 = readl(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
	37	static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
	38	{
	39	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	40	u32 timeout;
	41
	42	timeout = wdt->rate * wdog->timeout;
	43
	44	writel(timeout, wdt->base + WDT_TIMEOUT_REG);
	45	}
	46
	47	static int bcm7038_wdt_ping(struct watchdog_device *wdog)
	48	{
	49	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	50
	51	writel(WDT_START_1, wdt->base + WDT_CMD_REG);
	52	writel(WDT_START_2, wdt->base + WDT_CMD_REG);
	53
	54	return 0;
	55	}
	56
	57	static int bcm7038_wdt_start(struct watchdog_device *wdog)
	58	{
	59	bcm7038_wdt_set_timeout_reg(wdog);
	60	bcm7038_wdt_ping(wdog);
	61
	62	return 0;
	63	}
	64
	65	static int bcm7038_wdt_stop(struct watchdog_device *wdog)
	66	{
	67	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
	68
69	writel(WDT_STOP_1, wdt->base + WDT_CMD_REG);
70	writel(WDT_STOP_2, wdt->base + WDT_CMD_REG);
71
72	return 0;
73	}
74
75	static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog,
76	unsigned int t)
77	{
78	/* Can't modify timeout value if watchdog timer is running */
79	bcm7038_wdt_stop(wdog);
80	wdog->timeout = t;
81	bcm7038_wdt_start(wdog);
82
83	return 0;
84	}
85
86	static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)
87	{
88	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
89	u32 time_left;
90
91	time_left = readl(wdt->base + WDT_CMD_REG);
92
93	return time_left / wdt->rate;
94	}
95
6c368932	96	static const struct watchdog_info bcm7038_wdt_info = {
7a3629fe JC	97	.identity = "Broadcom BCM7038 Watchdog Timer",
	98	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
	99	WDIOF_MAGICCLOSE
	100	};
	101
85f15cfc	102	static const struct watchdog_ops bcm7038_wdt_ops = {
7a3629fe JC	103	.owner = THIS_MODULE,
	104	.start = bcm7038_wdt_start,
	105	.stop = bcm7038_wdt_stop,
	106	.set_timeout = bcm7038_wdt_set_timeout,
	107	.get_timeleft = bcm7038_wdt_get_timeleft,
	108	};
	109
69656dcd GR	110	static void bcm7038_clk_disable_unprepare(void *data)
	111	{
	112	clk_disable_unprepare(data);
	113	}
	114
7a3629fe JC	115	static int bcm7038_wdt_probe(struct platform_device *pdev)
	116	{
	117	struct device *dev = &pdev->dev;
	118	struct bcm7038_watchdog *wdt;
7a3629fe JC	119	int err;
	120
	121	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
	122	if (!wdt)
	123	return -ENOMEM;
	124
	125	platform_set_drvdata(pdev, wdt);
	126
0f0a6a28	127	wdt->base = devm_platform_ioremap_resource(pdev, 0);
7a3629fe JC	128	if (IS_ERR(wdt->base))
	129	return PTR_ERR(wdt->base);
	130
	131	wdt->clk = devm_clk_get(dev, NULL);
	132	/* If unable to get clock, use default frequency */
	133	if (!IS_ERR(wdt->clk)) {
dd0a18ca	134	err = clk_prepare_enable(wdt->clk);
69656dcd GR	135	if (err)
	136	return err;
	137	err = devm_add_action_or_reset(dev,
	138	bcm7038_clk_disable_unprepare,
	139	wdt->clk);
dd0a18ca FE	140	if (err)
dd0a18ca FE	141	return err;
7a3629fe JC	142	wdt->rate = clk_get_rate(wdt->clk);
	143	/* Prevent divide-by-zero exception */
	144	if (!wdt->rate)
	145	wdt->rate = WDT_DEFAULT_RATE;
	146	} else {
	147	wdt->rate = WDT_DEFAULT_RATE;
	148	wdt->clk = NULL;
	149	}
	150
	151	wdt->wdd.info = &bcm7038_wdt_info;
	152	wdt->wdd.ops = &bcm7038_wdt_ops;
	153	wdt->wdd.min_timeout = WDT_MIN_TIMEOUT;
	154	wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
	155	wdt->wdd.max_timeout = 0xffffffff / wdt->rate;
	156	wdt->wdd.parent = dev;
	157	watchdog_set_drvdata(&wdt->wdd, wdt);
	158
69656dcd GR	159	watchdog_stop_on_reboot(&wdt->wdd);
	160	watchdog_stop_on_unregister(&wdt->wdd);
	161	err = devm_watchdog_register_device(dev, &wdt->wdd);
f5429895	162	if (err)
7a3629fe	163	return err;
7a3629fe JC	164
	165	dev_info(dev, "Registered BCM7038 Watchdog\n");
	166
	167	return 0;
	168	}
	169
7a3629fe JC	170	#ifdef CONFIG_PM_SLEEP
	171	static int bcm7038_wdt_suspend(struct device *dev)
	172	{
	173	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
	174
	175	if (watchdog_active(&wdt->wdd))
	176	return bcm7038_wdt_stop(&wdt->wdd);
	177
	178	return 0;
	179	}
	180
	181	static int bcm7038_wdt_resume(struct device *dev)
	182	{
	183	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
	184
	185	if (watchdog_active(&wdt->wdd))
	186	return bcm7038_wdt_start(&wdt->wdd);
	187
	188	return 0;
	189	}
	190	#endif
	191
	192	static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend,
	193	bcm7038_wdt_resume);
	194
7a3629fe JC	195	static const struct of_device_id bcm7038_wdt_match[] = {
	196	{ .compatible = "brcm,bcm7038-wdt" },
	197	{},
	198	};
57d77c62	199	MODULE_DEVICE_TABLE(of, bcm7038_wdt_match);
7a3629fe JC	200
	201	static struct platform_driver bcm7038_wdt_driver = {
	202	.probe = bcm7038_wdt_probe,
7a3629fe JC	203	.driver = {
	204	.name = "bcm7038-wdt",
	205	.of_match_table = bcm7038_wdt_match,
	206	.pm = &bcm7038_wdt_pm_ops,
	207	}
	208	};
	209	module_platform_driver(bcm7038_wdt_driver);
	210
	211	module_param(nowayout, bool, 0);
	212	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	213	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
2e62c498	214	MODULE_LICENSE("GPL");
7a3629fe JC	215	MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
7a3629fe JC	216	MODULE_AUTHOR("Justin Chen");