[mirror_ubuntu-zesty-kernel.git] / drivers / watchdog / bcm2835_wdt.c

/*
 * Watchdog driver for Broadcom BCM2835
 *
 * "bcm2708_wdog" driver written by Luke Diamand that was obtained from
 * branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used
 * as a hardware reference for the Broadcom BCM2835 watchdog timer.
 *
 * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
 *
 * 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/delay.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>

#define PM_RSTC				0x1c
#define PM_RSTS				0x20
#define PM_WDOG				0x24

#define PM_PASSWORD			0x5a000000

#define PM_WDOG_TIME_SET		0x000fffff
#define PM_RSTC_WRCFG_CLR		0xffffffcf
#define PM_RSTS_HADWRH_SET		0x00000040
#define PM_RSTC_WRCFG_SET		0x00000030
#define PM_RSTC_WRCFG_FULL_RESET	0x00000020
#define PM_RSTC_RESET			0x00000102
#define PM_RSTS_PARTITION_CLR		0xfffffaaa

#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)

struct bcm2835_wdt {
	void __iomem		*base;
	spinlock_t		lock;
	struct notifier_block	restart_handler;
};

static unsigned int heartbeat;
static bool nowayout = WATCHDOG_NOWAYOUT;

static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt)
{
	uint32_t cur;

	cur = readl(wdt->base + PM_RSTC);

	return !!(cur & PM_RSTC_WRCFG_FULL_RESET);
}

static int bcm2835_wdt_start(struct watchdog_device *wdog)
{
	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
	uint32_t cur;
	unsigned long flags;

	spin_lock_irqsave(&wdt->lock, flags);

	writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
				PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
	cur = readl_relaxed(wdt->base + PM_RSTC);
	writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
		  PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);

	spin_unlock_irqrestore(&wdt->lock, flags);

	return 0;
}

static int bcm2835_wdt_stop(struct watchdog_device *wdog)
{
	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);

	writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
	return 0;
}

static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
{
	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);

	uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
	return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
}

static const struct watchdog_ops bcm2835_wdt_ops = {
	.owner =	THIS_MODULE,
	.start =	bcm2835_wdt_start,
	.stop =		bcm2835_wdt_stop,
	.get_timeleft =	bcm2835_wdt_get_timeleft,
};

static const struct watchdog_info bcm2835_wdt_info = {
	.options =	WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
			WDIOF_KEEPALIVEPING,
	.identity =	"Broadcom BCM2835 Watchdog timer",
};

static struct watchdog_device bcm2835_wdt_wdd = {
	.info =		&bcm2835_wdt_info,
	.ops =		&bcm2835_wdt_ops,
	.min_timeout =	1,
	.max_timeout =	WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
	.timeout =	WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
};

/*
 * The Raspberry Pi firmware uses the RSTS register to know which partiton
 * to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10.
 * Partiton 63 is a special partition used by the firmware to indicate halt.
 */

static void bcm2835_restart(struct bcm2835_wdt *wdt, u8 partition)
{
	u32 val, rsts;

	rsts = (partition & BIT(0)) | ((partition & BIT(1)) << 1) |
	       ((partition & BIT(2)) << 2) | ((partition & BIT(3)) << 3) |
	       ((partition & BIT(4)) << 4) | ((partition & BIT(5)) << 5);

	val = readl_relaxed(wdt->base + PM_RSTS);
	val &= PM_RSTS_PARTITION_CLR;
	val |= PM_PASSWORD | rsts;
	writel_relaxed(val, wdt->base + PM_RSTS);

	/* use a timeout of 10 ticks (~150us) */
	writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);

	val = readl_relaxed(wdt->base + PM_RSTC);
	val &= PM_RSTC_WRCFG_CLR;
	val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
	writel_relaxed(val, wdt->base + PM_RSTC);

	/* No sleeping, possibly atomic. */
	mdelay(1);
}

static int bcm2835_restart_notifier_call(struct notifier_block *this,
					 unsigned long mode, void *cmd)
{
	struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt,
					       restart_handler);
	unsigned long long val;
	u8 partition = 0;

	if (cmd && !kstrtoull(cmd, 0, &val) && val <= 63)
		partition = val;

	bcm2835_restart(wdt, partition);

	return 0;
}

/*
 * We can't really power off, but if we do the normal reset scheme, and
 * indicate to bootcode.bin not to reboot, then most of the chip will be
 * powered off.
 */
static void bcm2835_power_off(void)
{
	struct device_node *np =
		of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
	struct platform_device *pdev = of_find_device_by_node(np);
	struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);

	/* Partition 63 tells the firmware that this is a halt */
	bcm2835_restart(wdt, 63);
}

static int bcm2835_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct bcm2835_wdt *wdt;
	int err;

	wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
	if (!wdt)
		return -ENOMEM;
	platform_set_drvdata(pdev, wdt);

	spin_lock_init(&wdt->lock);

	wdt->base = of_iomap(np, 0);
	if (!wdt->base) {
		dev_err(dev, "Failed to remap watchdog regs");
		return -ENODEV;
	}

	watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
	watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
	watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
	bcm2835_wdt_wdd.parent = &pdev->dev;
	if (bcm2835_wdt_is_running(wdt)) {
		/*
		 * The currently active timeout value (set by the
		 * bootloader) may be different from the module
		 * heartbeat parameter or the value in device
		 * tree. But we just need to set WDOG_HW_RUNNING,
		 * because then the framework will "immediately" ping
		 * the device, updating the timeout.
		 */
		set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status);
	}
	err = watchdog_register_device(&bcm2835_wdt_wdd);
	if (err) {
		dev_err(dev, "Failed to register watchdog device");
		iounmap(wdt->base);
		return err;
	}

	wdt->restart_handler.notifier_call = bcm2835_restart_notifier_call;
	wdt->restart_handler.priority = 128;
	register_restart_handler(&wdt->restart_handler);
	if (pm_power_off == NULL)
		pm_power_off = bcm2835_power_off;

	dev_info(dev, "Broadcom BCM2835 watchdog timer");
	return 0;
}

static int bcm2835_wdt_remove(struct platform_device *pdev)
{
	struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);

	unregister_restart_handler(&wdt->restart_handler);
	if (pm_power_off == bcm2835_power_off)
		pm_power_off = NULL;
	watchdog_unregister_device(&bcm2835_wdt_wdd);
	iounmap(wdt->base);

	return 0;
}

static void bcm2835_wdt_shutdown(struct platform_device *pdev)
{
	bcm2835_wdt_stop(&bcm2835_wdt_wdd);
}

static const struct of_device_id bcm2835_wdt_of_match[] = {
	{ .compatible = "brcm,bcm2835-pm-wdt", },
	{},
};
MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);

static struct platform_driver bcm2835_wdt_driver = {
	.probe		= bcm2835_wdt_probe,
	.remove		= bcm2835_wdt_remove,
	.shutdown	= bcm2835_wdt_shutdown,
	.driver = {
		.name =		"bcm2835-wdt",
		.of_match_table = bcm2835_wdt_of_match,
	},
};
module_platform_driver(bcm2835_wdt_driver);

module_param(heartbeat, uint, 0);
MODULE_PARM_DESC(heartbeat, "Initial 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_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
MODULE_LICENSE("GPL");
Commit	Line	Data
938d0a84 LR	1	/*
	2	* Watchdog driver for Broadcom BCM2835
	3	*
	4	* "bcm2708_wdog" driver written by Luke Diamand that was obtained from
	5	* branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used
	6	* as a hardware reference for the Broadcom BCM2835 watchdog timer.
	7	*
	8	* Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
	9	*
	10	* This program is free software; you can redistribute it and/or modify it
	11	* under the terms of the GNU General Public License as published by the
	12	* Free Software Foundation; either version 2 of the License, or (at your
	13	* option) any later version.
	14	*/
	15
33a9f5bc EA	16	#include <linux/delay.h>
33a9f5bc EA	17	#include <linux/reboot.h>
938d0a84 LR	18	#include <linux/types.h>
	19	#include <linux/module.h>
	20	#include <linux/io.h>
	21	#include <linux/watchdog.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/of_address.h>
33a9f5bc	24	#include <linux/of_platform.h>
938d0a84 LR	25
938d0a84 LR	26	#define PM_RSTC 0x1c
33a9f5bc	27	#define PM_RSTS 0x20
938d0a84 LR	28	#define PM_WDOG 0x24
	29
	30	#define PM_PASSWORD 0x5a000000
	31
	32	#define PM_WDOG_TIME_SET 0x000fffff
	33	#define PM_RSTC_WRCFG_CLR 0xffffffcf
33a9f5bc	34	#define PM_RSTS_HADWRH_SET 0x00000040
938d0a84 LR	35	#define PM_RSTC_WRCFG_SET 0x00000030
	36	#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
	37	#define PM_RSTC_RESET 0x00000102
275c4086	38	#define PM_RSTS_PARTITION_CLR 0xfffffaaa
898e6861	39
938d0a84 LR	40	#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
	41	#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
	42
	43	struct bcm2835_wdt {
	44	void __iomem *base;
	45	spinlock_t lock;
33a9f5bc	46	struct notifier_block restart_handler;
938d0a84 LR	47	};
	48
	49	static unsigned int heartbeat;
	50	static bool nowayout = WATCHDOG_NOWAYOUT;
	51
054ae194 RV	52	static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt)
	53	{
	54	uint32_t cur;
	55
	56	cur = readl(wdt->base + PM_RSTC);
	57
	58	return !!(cur & PM_RSTC_WRCFG_FULL_RESET);
	59	}
	60
938d0a84 LR	61	static int bcm2835_wdt_start(struct watchdog_device *wdog)
	62	{
	63	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
	64	uint32_t cur;
	65	unsigned long flags;
	66
	67	spin_lock_irqsave(&wdt->lock, flags);
	68
	69	writel_relaxed(PM_PASSWORD \| (SECS_TO_WDOG_TICKS(wdog->timeout) &
	70	PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
	71	cur = readl_relaxed(wdt->base + PM_RSTC);
	72	writel_relaxed(PM_PASSWORD \| (cur & PM_RSTC_WRCFG_CLR) \|
	73	PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
	74
	75	spin_unlock_irqrestore(&wdt->lock, flags);
	76
	77	return 0;
	78	}
	79
	80	static int bcm2835_wdt_stop(struct watchdog_device *wdog)
	81	{
	82	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
	83
	84	writel_relaxed(PM_PASSWORD \| PM_RSTC_RESET, wdt->base + PM_RSTC);
938d0a84 LR	85	return 0;
	86	}
	87
938d0a84 LR	88	static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
	89	{
	90	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
	91
	92	uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
	93	return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
	94	}
	95
aea4b477	96	static const struct watchdog_ops bcm2835_wdt_ops = {
938d0a84 LR	97	.owner = THIS_MODULE,
	98	.start = bcm2835_wdt_start,
	99	.stop = bcm2835_wdt_stop,
938d0a84 LR	100	.get_timeleft = bcm2835_wdt_get_timeleft,
	101	};
	102
aea4b477	103	static const struct watchdog_info bcm2835_wdt_info = {
938d0a84 LR	104	.options = WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE \|
	105	WDIOF_KEEPALIVEPING,
	106	.identity = "Broadcom BCM2835 Watchdog timer",
	107	};
	108
	109	static struct watchdog_device bcm2835_wdt_wdd = {
	110	.info = &bcm2835_wdt_info,
	111	.ops = &bcm2835_wdt_ops,
	112	.min_timeout = 1,
	113	.max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
	114	.timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
	115	};
	116
275c4086 NT	117	/*
	118	* The Raspberry Pi firmware uses the RSTS register to know which partiton
	119	* to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10.
	120	* Partiton 63 is a special partition used by the firmware to indicate halt.
	121	*/
	122
	123	static void bcm2835_restart(struct bcm2835_wdt *wdt, u8 partition)
33a9f5bc	124	{
275c4086 NT	125	u32 val, rsts;
	126
	127	rsts = (partition & BIT(0)) \| ((partition & BIT(1)) << 1) \|
	128	((partition & BIT(2)) << 2) \| ((partition & BIT(3)) << 3) \|
	129	((partition & BIT(4)) << 4) \| ((partition & BIT(5)) << 5);
	130
	131	val = readl_relaxed(wdt->base + PM_RSTS);
	132	val &= PM_RSTS_PARTITION_CLR;
	133	val \|= PM_PASSWORD \| rsts;
	134	writel_relaxed(val, wdt->base + PM_RSTS);
33a9f5bc EA	135
	136	/* use a timeout of 10 ticks (~150us) */
	137	writel_relaxed(10 \| PM_PASSWORD, wdt->base + PM_WDOG);
275c4086	138
33a9f5bc EA	139	val = readl_relaxed(wdt->base + PM_RSTC);
	140	val &= PM_RSTC_WRCFG_CLR;
	141	val \|= PM_PASSWORD \| PM_RSTC_WRCFG_FULL_RESET;
	142	writel_relaxed(val, wdt->base + PM_RSTC);
	143
	144	/* No sleeping, possibly atomic. */
	145	mdelay(1);
275c4086 NT	146	}
	147
	148	static int bcm2835_restart_notifier_call(struct notifier_block *this,
	149	unsigned long mode, void *cmd)
	150	{
	151	struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt,
	152	restart_handler);
	153	unsigned long long val;
	154	u8 partition = 0;
	155
	156	if (cmd && !kstrtoull(cmd, 0, &val) && val <= 63)
	157	partition = val;
	158
	159	bcm2835_restart(wdt, partition);
33a9f5bc EA	160
	161	return 0;
	162	}
	163
	164	/*
	165	* We can't really power off, but if we do the normal reset scheme, and
	166	* indicate to bootcode.bin not to reboot, then most of the chip will be
	167	* powered off.
	168	*/
	169	static void bcm2835_power_off(void)
	170	{
	171	struct device_node *np =
	172	of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
	173	struct platform_device *pdev = of_find_device_by_node(np);
	174	struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
33a9f5bc	175
275c4086 NT	176	/* Partition 63 tells the firmware that this is a halt */
275c4086 NT	177	bcm2835_restart(wdt, 63);
33a9f5bc EA	178	}
33a9f5bc EA	179
938d0a84 LR	180	static int bcm2835_wdt_probe(struct platform_device *pdev)
	181	{
	182	struct device *dev = &pdev->dev;
	183	struct device_node *np = dev->of_node;
	184	struct bcm2835_wdt *wdt;
	185	int err;
	186
	187	wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
8deea830	188	if (!wdt)
938d0a84	189	return -ENOMEM;
938d0a84 LR	190	platform_set_drvdata(pdev, wdt);
	191
	192	spin_lock_init(&wdt->lock);
	193
	194	wdt->base = of_iomap(np, 0);
	195	if (!wdt->base) {
	196	dev_err(dev, "Failed to remap watchdog regs");
	197	return -ENODEV;
	198	}
	199
	200	watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
	201	watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
	202	watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
6551881c	203	bcm2835_wdt_wdd.parent = &pdev->dev;
054ae194 RV	204	if (bcm2835_wdt_is_running(wdt)) {
	205	/*
	206	* The currently active timeout value (set by the
	207	* bootloader) may be different from the module
	208	* heartbeat parameter or the value in device
	209	* tree. But we just need to set WDOG_HW_RUNNING,
	210	* because then the framework will "immediately" ping
	211	* the device, updating the timeout.
	212	*/
	213	set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status);
	214	}
938d0a84 LR	215	err = watchdog_register_device(&bcm2835_wdt_wdd);
	216	if (err) {
	217	dev_err(dev, "Failed to register watchdog device");
	218	iounmap(wdt->base);
	219	return err;
	220	}
	221
275c4086	222	wdt->restart_handler.notifier_call = bcm2835_restart_notifier_call;
33a9f5bc EA	223	wdt->restart_handler.priority = 128;
	224	register_restart_handler(&wdt->restart_handler);
	225	if (pm_power_off == NULL)
	226	pm_power_off = bcm2835_power_off;
	227
938d0a84 LR	228	dev_info(dev, "Broadcom BCM2835 watchdog timer");
	229	return 0;
	230	}
	231
	232	static int bcm2835_wdt_remove(struct platform_device *pdev)
	233	{
	234	struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
	235
33a9f5bc EA	236	unregister_restart_handler(&wdt->restart_handler);
	237	if (pm_power_off == bcm2835_power_off)
	238	pm_power_off = NULL;
938d0a84 LR	239	watchdog_unregister_device(&bcm2835_wdt_wdd);
	240	iounmap(wdt->base);
	241
	242	return 0;
	243	}
	244
	245	static void bcm2835_wdt_shutdown(struct platform_device *pdev)
	246	{
	247	bcm2835_wdt_stop(&bcm2835_wdt_wdd);
	248	}
	249
	250	static const struct of_device_id bcm2835_wdt_of_match[] = {
	251	{ .compatible = "brcm,bcm2835-pm-wdt", },
	252	{},
	253	};
	254	MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
	255
	256	static struct platform_driver bcm2835_wdt_driver = {
	257	.probe = bcm2835_wdt_probe,
	258	.remove = bcm2835_wdt_remove,
	259	.shutdown = bcm2835_wdt_shutdown,
	260	.driver = {
	261	.name = "bcm2835-wdt",
938d0a84 LR	262	.of_match_table = bcm2835_wdt_of_match,
	263	},
	264	};
	265	module_platform_driver(bcm2835_wdt_driver);
	266
	267	module_param(heartbeat, uint, 0);
	268	MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
	269
	270	module_param(nowayout, bool, 0);
	271	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	272	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	273
	274	MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
	275	MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
	276	MODULE_LICENSE("GPL");