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

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

	platform_set_drvdata(pdev, wdt);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	wdt->base = devm_ioremap_resource(dev, res);
	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;
		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);

	err = watchdog_register_device(&wdt->wdd);
	if (err) {
		dev_err(dev, "Failed to register watchdog device\n");
		clk_disable_unprepare(wdt->clk);
		return err;
	}

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

	return 0;
}

static int bcm7038_wdt_remove(struct platform_device *pdev)
{
	struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev);

	if (!nowayout)
		bcm7038_wdt_stop(&wdt->wdd);

	watchdog_unregister_device(&wdt->wdd);
	clk_disable_unprepare(wdt->clk);

	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 void bcm7038_wdt_shutdown(struct platform_device *pdev)
{
	struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev);

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

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,
	.remove		= bcm7038_wdt_remove,
	.shutdown	= bcm7038_wdt_shutdown,
	.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
	110	static int bcm7038_wdt_probe(struct platform_device *pdev)
	111	{
	112	struct device *dev = &pdev->dev;
	113	struct bcm7038_watchdog *wdt;
	114	struct resource *res;
	115	int err;
	116
	117	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
	118	if (!wdt)
	119	return -ENOMEM;
	120
	121	platform_set_drvdata(pdev, wdt);
	122
	123	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	124	wdt->base = devm_ioremap_resource(dev, res);
	125	if (IS_ERR(wdt->base))
	126	return PTR_ERR(wdt->base);
	127
	128	wdt->clk = devm_clk_get(dev, NULL);
	129	/* If unable to get clock, use default frequency */
	130	if (!IS_ERR(wdt->clk)) {
dd0a18ca FE	131	err = clk_prepare_enable(wdt->clk);
	132	if (err)
	133	return err;
7a3629fe JC	134	wdt->rate = clk_get_rate(wdt->clk);
	135	/* Prevent divide-by-zero exception */
	136	if (!wdt->rate)
	137	wdt->rate = WDT_DEFAULT_RATE;
	138	} else {
	139	wdt->rate = WDT_DEFAULT_RATE;
	140	wdt->clk = NULL;
	141	}
	142
	143	wdt->wdd.info = &bcm7038_wdt_info;
	144	wdt->wdd.ops = &bcm7038_wdt_ops;
	145	wdt->wdd.min_timeout = WDT_MIN_TIMEOUT;
	146	wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
	147	wdt->wdd.max_timeout = 0xffffffff / wdt->rate;
	148	wdt->wdd.parent = dev;
	149	watchdog_set_drvdata(&wdt->wdd, wdt);
	150
	151	err = watchdog_register_device(&wdt->wdd);
	152	if (err) {
	153	dev_err(dev, "Failed to register watchdog device\n");
	154	clk_disable_unprepare(wdt->clk);
	155	return err;
	156	}
	157
	158	dev_info(dev, "Registered BCM7038 Watchdog\n");
	159
	160	return 0;
	161	}
	162
	163	static int bcm7038_wdt_remove(struct platform_device *pdev)
	164	{
	165	struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev);
	166
	167	if (!nowayout)
	168	bcm7038_wdt_stop(&wdt->wdd);
	169
	170	watchdog_unregister_device(&wdt->wdd);
	171	clk_disable_unprepare(wdt->clk);
	172
	173	return 0;
	174	}
	175
	176	#ifdef CONFIG_PM_SLEEP
	177	static int bcm7038_wdt_suspend(struct device *dev)
	178	{
	179	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
	180
	181	if (watchdog_active(&wdt->wdd))
	182	return bcm7038_wdt_stop(&wdt->wdd);
	183
	184	return 0;
	185	}
	186
	187	static int bcm7038_wdt_resume(struct device *dev)
	188	{
	189	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
	190
	191	if (watchdog_active(&wdt->wdd))
	192	return bcm7038_wdt_start(&wdt->wdd);
	193
	194	return 0;
	195	}
	196	#endif
	197
198	static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend,
199	bcm7038_wdt_resume);
200
201	static void bcm7038_wdt_shutdown(struct platform_device *pdev)
202	{
203	struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev);
204
205	if (watchdog_active(&wdt->wdd))
206	bcm7038_wdt_stop(&wdt->wdd);
207	}
208
209	static const struct of_device_id bcm7038_wdt_match[] = {
210	{ .compatible = "brcm,bcm7038-wdt" },
211	{},
212	};
57d77c62	213	MODULE_DEVICE_TABLE(of, bcm7038_wdt_match);
7a3629fe JC	214
	215	static struct platform_driver bcm7038_wdt_driver = {
	216	.probe = bcm7038_wdt_probe,
	217	.remove = bcm7038_wdt_remove,
	218	.shutdown = bcm7038_wdt_shutdown,
	219	.driver = {
	220	.name = "bcm7038-wdt",
	221	.of_match_table = bcm7038_wdt_match,
	222	.pm = &bcm7038_wdt_pm_ops,
	223	}
	224	};
	225	module_platform_driver(bcm7038_wdt_driver);
	226
	227	module_param(nowayout, bool, 0);
	228	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	229	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
2e62c498	230	MODULE_LICENSE("GPL");
7a3629fe JC	231	MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
7a3629fe JC	232	MODULE_AUTHOR("Justin Chen");