1// SPDX-License-Identifier: GPL-2.0+
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 *
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/bitops.h>
13#include <linux/errno.h>
14#include <linux/fs.h>
15#include <linux/io.h>
16#include <linux/kernel.h>
17#include <linux/miscdevice.h>
18#include <linux/module.h>
19#include <linux/moduleparam.h>
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
41static struct {
42	void __iomem *regs;
43	struct timer_list timer;
44	unsigned long inuse;
45	atomic_t ticks;
46} bcm63xx_wdt_device;
47
48static int expect_close;
49
50static int wdt_time = WDT_DEFAULT_TIME;
51static bool nowayout = WATCHDOG_NOWAYOUT;
52module_param(nowayout, bool, 0);
53MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
54	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
55
56/* HW functions */
57static 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
64static 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
70static void bcm63xx_wdt_isr(void *data)
71{
72	struct pt_regs *regs = get_irq_regs();
73
74	die(PFX " fire", regs);
75}
76
77static void bcm63xx_timer_tick(struct timer_list *unused)
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
83		pr_crit("watchdog will restart system\n");
84}
85
86static void bcm63xx_wdt_pet(void)
87{
88	atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
89}
90
91static void bcm63xx_wdt_start(void)
92{
93	bcm63xx_wdt_pet();
94	bcm63xx_timer_tick(0);
95}
96
97static void bcm63xx_wdt_pause(void)
98{
99	del_timer_sync(&bcm63xx_wdt_device.timer);
100	bcm63xx_wdt_hw_stop();
101}
102
103static 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
113static 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();
119	return stream_open(inode, file);
120}
121
122static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
123{
124	if (expect_close == 42)
125		bcm63xx_wdt_pause();
126	else {
127		pr_crit("Unexpected close, not stopping watchdog!\n");
128		bcm63xx_wdt_start();
129	}
130	clear_bit(0, &bcm63xx_wdt_device.inuse);
131	expect_close = 0;
132	return 0;
133}
134
135static 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
158static struct watchdog_info bcm63xx_wdt_info = {
159	.identity       = PFX,
160	.options        = WDIOF_SETTIMEOUT |
161				WDIOF_KEEPALIVEPING |
162				WDIOF_MAGICCLOSE,
163};
164
165
166static 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
219static 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,
224	.compat_ioctl	= compat_ptr_ioctl,
225	.open		= bcm63xx_wdt_open,
226	.release	= bcm63xx_wdt_release,
227};
228
229static struct miscdevice bcm63xx_wdt_miscdev = {
230	.minor	= WATCHDOG_MINOR,
231	.name	= "watchdog",
232	.fops	= &bcm63xx_wdt_fops,
233};
234
235
236static int bcm63xx_wdt_probe(struct platform_device *pdev)
237{
238	int ret;
239	struct resource *r;
240
241	timer_setup(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0);
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
249	bcm63xx_wdt_device.regs = devm_ioremap(&pdev->dev, r->start,
250							resource_size(r));
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");
259		return ret;
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
269	ret = misc_register(&bcm63xx_wdt_miscdev);
270	if (ret < 0) {
271		dev_err(&pdev->dev, "failed to register watchdog device\n");
272		goto unregister_timer;
273	}
274
275	dev_info(&pdev->dev, " started, timer margin: %d sec\n",
276						WDT_DEFAULT_TIME);
277
278	return 0;
279
280unregister_timer:
281	bcm63xx_timer_unregister(TIMER_WDT_ID);
282	return ret;
283}
284
285static int bcm63xx_wdt_remove(struct platform_device *pdev)
286{
287	if (!nowayout)
288		bcm63xx_wdt_pause();
289
290	misc_deregister(&bcm63xx_wdt_miscdev);
291	bcm63xx_timer_unregister(TIMER_WDT_ID);
292	return 0;
293}
294
295static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
296{
297	bcm63xx_wdt_pause();
298}
299
300static struct platform_driver bcm63xx_wdt_driver = {
301	.probe	= bcm63xx_wdt_probe,
302	.remove = bcm63xx_wdt_remove,
303	.shutdown = bcm63xx_wdt_shutdown,
304	.driver = {
305		.name = "bcm63xx-wdt",
306	}
307};
308
309module_platform_driver(bcm63xx_wdt_driver);
310
311MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
312MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
313MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
314MODULE_LICENSE("GPL");
315MODULE_ALIAS("platform:bcm63xx-wdt");
316