1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Watchdog driver for Broadcom BCM47XX
4  *
5  *  Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs>
6  *  Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr>
7  *  Copyright (C) 2012-2013 Hauke Mehrtens <hauke@hauke-m.de>
8  *
9  */
10 
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 
13 #include <linux/bcm47xx_wdt.h>
14 #include <linux/bitops.h>
15 #include <linux/errno.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/platform_device.h>
20 #include <linux/types.h>
21 #include <linux/watchdog.h>
22 #include <linux/timer.h>
23 #include <linux/jiffies.h>
24 
25 #define DRV_NAME		"bcm47xx_wdt"
26 
27 #define WDT_DEFAULT_TIME	30	/* seconds */
28 #define WDT_SOFTTIMER_MAX	255	/* seconds */
29 #define WDT_SOFTTIMER_THRESHOLD	60	/* seconds */
30 
31 static int timeout = WDT_DEFAULT_TIME;
32 static bool nowayout = WATCHDOG_NOWAYOUT;
33 
34 module_param(timeout, int, 0);
35 MODULE_PARM_DESC(timeout, "Watchdog time in seconds. (default="
36 				__MODULE_STRING(WDT_DEFAULT_TIME) ")");
37 
38 module_param(nowayout, bool, 0);
39 MODULE_PARM_DESC(nowayout,
40 		"Watchdog cannot be stopped once started (default="
41 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
42 
43 static inline struct bcm47xx_wdt *bcm47xx_wdt_get(struct watchdog_device *wdd)
44 {
45 	return container_of(wdd, struct bcm47xx_wdt, wdd);
46 }
47 
48 static int bcm47xx_wdt_hard_keepalive(struct watchdog_device *wdd)
49 {
50 	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
51 
52 	wdt->timer_set_ms(wdt, wdd->timeout * 1000);
53 
54 	return 0;
55 }
56 
57 static int bcm47xx_wdt_hard_start(struct watchdog_device *wdd)
58 {
59 	return 0;
60 }
61 
62 static int bcm47xx_wdt_hard_stop(struct watchdog_device *wdd)
63 {
64 	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
65 
66 	wdt->timer_set(wdt, 0);
67 
68 	return 0;
69 }
70 
71 static int bcm47xx_wdt_hard_set_timeout(struct watchdog_device *wdd,
72 					unsigned int new_time)
73 {
74 	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
75 	u32 max_timer = wdt->max_timer_ms;
76 
77 	if (new_time < 1 || new_time > max_timer / 1000) {
78 		pr_warn("timeout value must be 1<=x<=%d, using %d\n",
79 			max_timer / 1000, new_time);
80 		return -EINVAL;
81 	}
82 
83 	wdd->timeout = new_time;
84 	return 0;
85 }
86 
87 static int bcm47xx_wdt_restart(struct watchdog_device *wdd,
88 			       unsigned long action, void *data)
89 {
90 	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
91 
92 	wdt->timer_set(wdt, 1);
93 
94 	return 0;
95 }
96 
97 static const struct watchdog_ops bcm47xx_wdt_hard_ops = {
98 	.owner		= THIS_MODULE,
99 	.start		= bcm47xx_wdt_hard_start,
100 	.stop		= bcm47xx_wdt_hard_stop,
101 	.ping		= bcm47xx_wdt_hard_keepalive,
102 	.set_timeout	= bcm47xx_wdt_hard_set_timeout,
103 	.restart        = bcm47xx_wdt_restart,
104 };
105 
106 static void bcm47xx_wdt_soft_timer_tick(struct timer_list *t)
107 {
108 	struct bcm47xx_wdt *wdt = from_timer(wdt, t, soft_timer);
109 	u32 next_tick = min(wdt->wdd.timeout * 1000, wdt->max_timer_ms);
110 
111 	if (!atomic_dec_and_test(&wdt->soft_ticks)) {
112 		wdt->timer_set_ms(wdt, next_tick);
113 		mod_timer(&wdt->soft_timer, jiffies + HZ);
114 	} else {
115 		pr_crit("Watchdog will fire soon!!!\n");
116 	}
117 }
118 
119 static int bcm47xx_wdt_soft_keepalive(struct watchdog_device *wdd)
120 {
121 	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
122 
123 	atomic_set(&wdt->soft_ticks, wdd->timeout);
124 
125 	return 0;
126 }
127 
128 static int bcm47xx_wdt_soft_start(struct watchdog_device *wdd)
129 {
130 	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
131 
132 	bcm47xx_wdt_soft_keepalive(wdd);
133 	bcm47xx_wdt_soft_timer_tick(&wdt->soft_timer);
134 
135 	return 0;
136 }
137 
138 static int bcm47xx_wdt_soft_stop(struct watchdog_device *wdd)
139 {
140 	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
141 
142 	del_timer_sync(&wdt->soft_timer);
143 	wdt->timer_set(wdt, 0);
144 
145 	return 0;
146 }
147 
148 static int bcm47xx_wdt_soft_set_timeout(struct watchdog_device *wdd,
149 					unsigned int new_time)
150 {
151 	if (new_time < 1 || new_time > WDT_SOFTTIMER_MAX) {
152 		pr_warn("timeout value must be 1<=x<=%d, using %d\n",
153 			WDT_SOFTTIMER_MAX, new_time);
154 		return -EINVAL;
155 	}
156 
157 	wdd->timeout = new_time;
158 	return 0;
159 }
160 
161 static const struct watchdog_info bcm47xx_wdt_info = {
162 	.identity	= DRV_NAME,
163 	.options	= WDIOF_SETTIMEOUT |
164 				WDIOF_KEEPALIVEPING |
165 				WDIOF_MAGICCLOSE,
166 };
167 
168 static const struct watchdog_ops bcm47xx_wdt_soft_ops = {
169 	.owner		= THIS_MODULE,
170 	.start		= bcm47xx_wdt_soft_start,
171 	.stop		= bcm47xx_wdt_soft_stop,
172 	.ping		= bcm47xx_wdt_soft_keepalive,
173 	.set_timeout	= bcm47xx_wdt_soft_set_timeout,
174 	.restart        = bcm47xx_wdt_restart,
175 };
176 
177 static int bcm47xx_wdt_probe(struct platform_device *pdev)
178 {
179 	int ret;
180 	bool soft;
181 	struct bcm47xx_wdt *wdt = dev_get_platdata(&pdev->dev);
182 
183 	if (!wdt)
184 		return -ENXIO;
185 
186 	soft = wdt->max_timer_ms < WDT_SOFTTIMER_THRESHOLD * 1000;
187 
188 	if (soft) {
189 		wdt->wdd.ops = &bcm47xx_wdt_soft_ops;
190 		timer_setup(&wdt->soft_timer, bcm47xx_wdt_soft_timer_tick, 0);
191 	} else {
192 		wdt->wdd.ops = &bcm47xx_wdt_hard_ops;
193 	}
194 
195 	wdt->wdd.info = &bcm47xx_wdt_info;
196 	wdt->wdd.timeout = WDT_DEFAULT_TIME;
197 	wdt->wdd.parent = &pdev->dev;
198 	ret = wdt->wdd.ops->set_timeout(&wdt->wdd, timeout);
199 	if (ret)
200 		goto err_timer;
201 	watchdog_set_nowayout(&wdt->wdd, nowayout);
202 	watchdog_set_restart_priority(&wdt->wdd, 64);
203 	watchdog_stop_on_reboot(&wdt->wdd);
204 
205 	ret = watchdog_register_device(&wdt->wdd);
206 	if (ret)
207 		goto err_timer;
208 
209 	dev_info(&pdev->dev, "BCM47xx Watchdog Timer enabled (%d seconds%s%s)\n",
210 		timeout, nowayout ? ", nowayout" : "",
211 		soft ? ", Software Timer" : "");
212 	return 0;
213 
214 err_timer:
215 	if (soft)
216 		del_timer_sync(&wdt->soft_timer);
217 
218 	return ret;
219 }
220 
221 static int bcm47xx_wdt_remove(struct platform_device *pdev)
222 {
223 	struct bcm47xx_wdt *wdt = dev_get_platdata(&pdev->dev);
224 
225 	watchdog_unregister_device(&wdt->wdd);
226 
227 	return 0;
228 }
229 
230 static struct platform_driver bcm47xx_wdt_driver = {
231 	.driver		= {
232 		.name	= "bcm47xx-wdt",
233 	},
234 	.probe		= bcm47xx_wdt_probe,
235 	.remove		= bcm47xx_wdt_remove,
236 };
237 
238 module_platform_driver(bcm47xx_wdt_driver);
239 
240 MODULE_AUTHOR("Aleksandar Radovanovic");
241 MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
242 MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
243 MODULE_LICENSE("GPL");
244