[mirror_ubuntu-hirsute-kernel.git] / drivers / watchdog / bcm63xx_wdt.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *  Broadcom BCM63xx SoC watchdog driver
 *
 *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
 *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/watchdog.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/resource.h>
#include <linux/platform_device.h>

#include <bcm63xx_cpu.h>
#include <bcm63xx_io.h>
#include <bcm63xx_regs.h>
#include <bcm63xx_timer.h>

#define PFX KBUILD_MODNAME

#define WDT_HZ		50000000 /* Fclk */
#define WDT_DEFAULT_TIME	30      /* seconds */
#define WDT_MAX_TIME		256     /* seconds */

static struct {
	void __iomem *regs;
	struct timer_list timer;
	unsigned long inuse;
	atomic_t ticks;
} bcm63xx_wdt_device;

static int expect_close;

static int wdt_time = WDT_DEFAULT_TIME;
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

/* HW functions */
static void bcm63xx_wdt_hw_start(void)
{
	bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
	bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
	bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
}

static void bcm63xx_wdt_hw_stop(void)
{
	bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
	bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
}

static void bcm63xx_wdt_isr(void *data)
{
	struct pt_regs *regs = get_irq_regs();

	die(PFX " fire", regs);
}

static void bcm63xx_timer_tick(struct timer_list *unused)
{
	if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
		bcm63xx_wdt_hw_start();
		mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
	} else
		pr_crit("watchdog will restart system\n");
}

static void bcm63xx_wdt_pet(void)
{
	atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
}

static void bcm63xx_wdt_start(void)
{
	bcm63xx_wdt_pet();
	bcm63xx_timer_tick(0);
}

static void bcm63xx_wdt_pause(void)
{
	del_timer_sync(&bcm63xx_wdt_device.timer);
	bcm63xx_wdt_hw_stop();
}

static int bcm63xx_wdt_settimeout(int new_time)
{
	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
		return -EINVAL;

	wdt_time = new_time;

	return 0;
}

static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
		return -EBUSY;

	bcm63xx_wdt_start();
	return stream_open(inode, file);
}

static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close == 42)
		bcm63xx_wdt_pause();
	else {
		pr_crit("Unexpected close, not stopping watchdog!\n");
		bcm63xx_wdt_start();
	}
	clear_bit(0, &bcm63xx_wdt_device.inuse);
	expect_close = 0;
	return 0;
}

static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
				size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			/* In case it was set long ago */
			expect_close = 0;

			for (i = 0; i != len; i++) {
				char c;
				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					expect_close = 42;
			}
		}
		bcm63xx_wdt_pet();
	}
	return len;
}

static struct watchdog_info bcm63xx_wdt_info = {
	.identity       = PFX,
	.options        = WDIOF_SETTIMEOUT |
				WDIOF_KEEPALIVEPING |
				WDIOF_MAGICCLOSE,
};


static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_value, retval = -EINVAL;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &bcm63xx_wdt_info,
			sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);

	case WDIOC_SETOPTIONS:
		if (get_user(new_value, p))
			return -EFAULT;

		if (new_value & WDIOS_DISABLECARD) {
			bcm63xx_wdt_pause();
			retval = 0;
		}
		if (new_value & WDIOS_ENABLECARD) {
			bcm63xx_wdt_start();
			retval = 0;
		}

		return retval;

	case WDIOC_KEEPALIVE:
		bcm63xx_wdt_pet();
		return 0;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_value, p))
			return -EFAULT;

		if (bcm63xx_wdt_settimeout(new_value))
			return -EINVAL;

		bcm63xx_wdt_pet();

	case WDIOC_GETTIMEOUT:
		return put_user(wdt_time, p);

	default:
		return -ENOTTY;

	}
}

static const struct file_operations bcm63xx_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= bcm63xx_wdt_write,
	.unlocked_ioctl	= bcm63xx_wdt_ioctl,
	.compat_ioctl	= compat_ptr_ioctl,
	.open		= bcm63xx_wdt_open,
	.release	= bcm63xx_wdt_release,
};

static struct miscdevice bcm63xx_wdt_miscdev = {
	.minor	= WATCHDOG_MINOR,
	.name	= "watchdog",
	.fops	= &bcm63xx_wdt_fops,
};


static int bcm63xx_wdt_probe(struct platform_device *pdev)
{
	int ret;
	struct resource *r;

	timer_setup(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
		dev_err(&pdev->dev, "failed to get resources\n");
		return -ENODEV;
	}

	bcm63xx_wdt_device.regs = devm_ioremap(&pdev->dev, r->start,
							resource_size(r));
	if (!bcm63xx_wdt_device.regs) {
		dev_err(&pdev->dev, "failed to remap I/O resources\n");
		return -ENXIO;
	}

	ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to register wdt timer isr\n");
		return ret;
	}

	if (bcm63xx_wdt_settimeout(wdt_time)) {
		bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
		dev_info(&pdev->dev,
			": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
			wdt_time);
	}

	ret = misc_register(&bcm63xx_wdt_miscdev);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to register watchdog device\n");
		goto unregister_timer;
	}

	dev_info(&pdev->dev, " started, timer margin: %d sec\n",
						WDT_DEFAULT_TIME);

	return 0;

unregister_timer:
	bcm63xx_timer_unregister(TIMER_WDT_ID);
	return ret;
}

static int bcm63xx_wdt_remove(struct platform_device *pdev)
{
	if (!nowayout)
		bcm63xx_wdt_pause();

	misc_deregister(&bcm63xx_wdt_miscdev);
	bcm63xx_timer_unregister(TIMER_WDT_ID);
	return 0;
}

static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
{
	bcm63xx_wdt_pause();
}

static struct platform_driver bcm63xx_wdt_driver = {
	.probe	= bcm63xx_wdt_probe,
	.remove = bcm63xx_wdt_remove,
	.shutdown = bcm63xx_wdt_shutdown,
	.driver = {
		.name = "bcm63xx-wdt",
	}
};

module_platform_driver(bcm63xx_wdt_driver);

MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:bcm63xx-wdt");
Commit	Line	Data
2e62c498	1	// SPDX-License-Identifier: GPL-2.0+
b63aa731 FF	2	/*
	3	* Broadcom BCM63xx SoC watchdog driver
	4	*
	5	* Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
	6	* Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
	7	*
b63aa731 FF	8	*/
b63aa731 FF	9
27c766aa JP	10	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	11
b63aa731 FF	12	#include <linux/bitops.h>
	13	#include <linux/errno.h>
	14	#include <linux/fs.h>
626d65aa	15	#include <linux/io.h>
b63aa731 FF	16	#include <linux/kernel.h>
	17	#include <linux/miscdevice.h>
	18	#include <linux/module.h>
	19	#include <linux/moduleparam.h>
b63aa731 FF	20	#include <linux/types.h>
	21	#include <linux/uaccess.h>
	22	#include <linux/watchdog.h>
	23	#include <linux/timer.h>
	24	#include <linux/jiffies.h>
	25	#include <linux/interrupt.h>
	26	#include <linux/ptrace.h>
	27	#include <linux/resource.h>
	28	#include <linux/platform_device.h>
	29
	30	#include <bcm63xx_cpu.h>
	31	#include <bcm63xx_io.h>
	32	#include <bcm63xx_regs.h>
	33	#include <bcm63xx_timer.h>
	34
	35	#define PFX KBUILD_MODNAME
	36
	37	#define WDT_HZ 50000000 /* Fclk */
	38	#define WDT_DEFAULT_TIME 30 /* seconds */
	39	#define WDT_MAX_TIME 256 /* seconds */
	40
	41	static struct {
	42	void __iomem *regs;
	43	struct timer_list timer;
b63aa731 FF	44	unsigned long inuse;
	45	atomic_t ticks;
	46	} bcm63xx_wdt_device;
	47
	48	static int expect_close;
	49
	50	static int wdt_time = WDT_DEFAULT_TIME;
86a1e189 WVS	51	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	52	module_param(nowayout, bool, 0);
b63aa731 FF	53	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	54	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	55
	56	/* HW functions */
	57	static void bcm63xx_wdt_hw_start(void)
	58	{
	59	bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
	60	bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
	61	bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
	62	}
	63
	64	static void bcm63xx_wdt_hw_stop(void)
	65	{
	66	bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
	67	bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
	68	}
	69
	70	static void bcm63xx_wdt_isr(void *data)
	71	{
	72	struct pt_regs *regs = get_irq_regs();
	73
	74	die(PFX " fire", regs);
	75	}
	76
e99e88a9	77	static void bcm63xx_timer_tick(struct timer_list *unused)
b63aa731 FF	78	{
	79	if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
	80	bcm63xx_wdt_hw_start();
	81	mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
	82	} else
27c766aa	83	pr_crit("watchdog will restart system\n");
b63aa731 FF	84	}
	85
	86	static void bcm63xx_wdt_pet(void)
	87	{
	88	atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
	89	}
	90
	91	static void bcm63xx_wdt_start(void)
	92	{
	93	bcm63xx_wdt_pet();
	94	bcm63xx_timer_tick(0);
	95	}
	96
	97	static void bcm63xx_wdt_pause(void)
	98	{
	99	del_timer_sync(&bcm63xx_wdt_device.timer);
	100	bcm63xx_wdt_hw_stop();
	101	}
	102
	103	static int bcm63xx_wdt_settimeout(int new_time)
	104	{
	105	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
	106	return -EINVAL;
	107
	108	wdt_time = new_time;
	109
	110	return 0;
	111	}
	112
	113	static int bcm63xx_wdt_open(struct inode inode, struct file file)
	114	{
	115	if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
	116	return -EBUSY;
	117
	118	bcm63xx_wdt_start();
c5bf68fe	119	return stream_open(inode, file);
b63aa731 FF	120	}
	121
	122	static int bcm63xx_wdt_release(struct inode inode, struct file file)
	123	{
	124	if (expect_close == 42)
	125	bcm63xx_wdt_pause();
	126	else {
27c766aa	127	pr_crit("Unexpected close, not stopping watchdog!\n");
b63aa731 FF	128	bcm63xx_wdt_start();
	129	}
	130	clear_bit(0, &bcm63xx_wdt_device.inuse);
	131	expect_close = 0;
	132	return 0;
	133	}
	134
	135	static ssize_t bcm63xx_wdt_write(struct file file, const char data,
	136	size_t len, loff_t *ppos)
	137	{
	138	if (len) {
	139	if (!nowayout) {
	140	size_t i;
	141
	142	/* In case it was set long ago */
	143	expect_close = 0;
	144
	145	for (i = 0; i != len; i++) {
	146	char c;
	147	if (get_user(c, data + i))
	148	return -EFAULT;
	149	if (c == 'V')
	150	expect_close = 42;
	151	}
	152	}
	153	bcm63xx_wdt_pet();
	154	}
	155	return len;
	156	}
	157
	158	static struct watchdog_info bcm63xx_wdt_info = {
	159	.identity = PFX,
	160	.options = WDIOF_SETTIMEOUT \|
	161	WDIOF_KEEPALIVEPING \|
	162	WDIOF_MAGICCLOSE,
	163	};
	164
	165
	166	static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
	167	unsigned long arg)
	168	{
	169	void __user argp = (void __user )arg;
	170	int __user *p = argp;
	171	int new_value, retval = -EINVAL;
	172
	173	switch (cmd) {
	174	case WDIOC_GETSUPPORT:
	175	return copy_to_user(argp, &bcm63xx_wdt_info,
	176	sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
	177
	178	case WDIOC_GETSTATUS:
	179	case WDIOC_GETBOOTSTATUS:
	180	return put_user(0, p);
	181
	182	case WDIOC_SETOPTIONS:
	183	if (get_user(new_value, p))
	184	return -EFAULT;
	185
	186	if (new_value & WDIOS_DISABLECARD) {
	187	bcm63xx_wdt_pause();
	188	retval = 0;
	189	}
	190	if (new_value & WDIOS_ENABLECARD) {
	191	bcm63xx_wdt_start();
192	retval = 0;
193	}
194
195	return retval;
196
197	case WDIOC_KEEPALIVE:
198	bcm63xx_wdt_pet();
199	return 0;
200
201	case WDIOC_SETTIMEOUT:
202	if (get_user(new_value, p))
203	return -EFAULT;
204
205	if (bcm63xx_wdt_settimeout(new_value))
206	return -EINVAL;
207
208	bcm63xx_wdt_pet();
209
210	case WDIOC_GETTIMEOUT:
211	return put_user(wdt_time, p);
212
213	default:
214	return -ENOTTY;
215
216	}
217	}
218
b63aa731 FF	219	static const struct file_operations bcm63xx_wdt_fops = {
	220	.owner = THIS_MODULE,
	221	.llseek = no_llseek,
	222	.write = bcm63xx_wdt_write,
	223	.unlocked_ioctl = bcm63xx_wdt_ioctl,
b6dfb247	224	.compat_ioctl = compat_ptr_ioctl,
b63aa731 FF	225	.open = bcm63xx_wdt_open,
	226	.release = bcm63xx_wdt_release,
	227	};
	228
	229	static struct miscdevice bcm63xx_wdt_miscdev = {
	230	.minor = WATCHDOG_MINOR,
	231	.name = "watchdog",
	232	.fops = &bcm63xx_wdt_fops,
	233	};
	234
b63aa731	235
2d991a16	236	static int bcm63xx_wdt_probe(struct platform_device *pdev)
b63aa731 FF	237	{
	238	int ret;
	239	struct resource *r;
	240
e99e88a9	241	timer_setup(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0);
b63aa731 FF	242
	243	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	244	if (!r) {
	245	dev_err(&pdev->dev, "failed to get resources\n");
	246	return -ENODEV;
	247	}
	248
4bdc0d67	249	bcm63xx_wdt_device.regs = devm_ioremap(&pdev->dev, r->start,
626d65aa	250	resource_size(r));
b63aa731 FF	251	if (!bcm63xx_wdt_device.regs) {
	252	dev_err(&pdev->dev, "failed to remap I/O resources\n");
	253	return -ENXIO;
	254	}
	255
	256	ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
	257	if (ret < 0) {
	258	dev_err(&pdev->dev, "failed to register wdt timer isr\n");
626d65aa	259	return ret;
b63aa731 FF	260	}
	261
	262	if (bcm63xx_wdt_settimeout(wdt_time)) {
	263	bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
	264	dev_info(&pdev->dev,
	265	": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
	266	wdt_time);
	267	}
	268
b63aa731 FF	269	ret = misc_register(&bcm63xx_wdt_miscdev);
	270	if (ret < 0) {
	271	dev_err(&pdev->dev, "failed to register watchdog device\n");
e6c3b699	272	goto unregister_timer;
b63aa731 FF	273	}
	274
	275	dev_info(&pdev->dev, " started, timer margin: %d sec\n",
	276	WDT_DEFAULT_TIME);
	277
	278	return 0;
	279
b63aa731 FF	280	unregister_timer:
b63aa731 FF	281	bcm63xx_timer_unregister(TIMER_WDT_ID);
b63aa731 FF	282	return ret;
	283	}
	284
4b12b896	285	static int bcm63xx_wdt_remove(struct platform_device *pdev)
b63aa731 FF	286	{
	287	if (!nowayout)
	288	bcm63xx_wdt_pause();
	289
	290	misc_deregister(&bcm63xx_wdt_miscdev);
b63aa731	291	bcm63xx_timer_unregister(TIMER_WDT_ID);
b63aa731 FF	292	return 0;
	293	}
	294
e6c3b699 WVS	295	static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
	296	{
	297	bcm63xx_wdt_pause();
	298	}
	299
5a135f3c	300	static struct platform_driver bcm63xx_wdt_driver = {
b63aa731	301	.probe = bcm63xx_wdt_probe,
82268714	302	.remove = bcm63xx_wdt_remove,
e6c3b699	303	.shutdown = bcm63xx_wdt_shutdown,
b63aa731 FF	304	.driver = {
	305	.name = "bcm63xx-wdt",
	306	}
	307	};
	308
5a135f3c	309	module_platform_driver(bcm63xx_wdt_driver);
b63aa731 FF	310
	311	MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
	312	MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
	313	MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
	314	MODULE_LICENSE("GPL");
b63aa731	315	MODULE_ALIAS("platform:bcm63xx-wdt");