1/*
2 *  Watchdog driver for Broadcom BCM47XX
3 *
4 *  Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs>
5 *  Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr>
6 *  Copyright (C) 2012-2013 Hauke Mehrtens <hauke@hauke-m.de>
7 *
8 *  This program is free software; you can redistribute it and/or
9 *  modify it under the terms of the GNU General Public License
10 *  as published by the Free Software Foundation; either version
11 *  2 of the License, or (at your option) any later version.
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/bcm47xx_wdt.h>
17#include <linux/bitops.h>
18#include <linux/errno.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/moduleparam.h>
22#include <linux/platform_device.h>
23#include <linux/reboot.h>
24#include <linux/types.h>
25#include <linux/watchdog.h>
26#include <linux/timer.h>
27#include <linux/jiffies.h>
28
29#define DRV_NAME		"bcm47xx_wdt"
30
31#define WDT_DEFAULT_TIME	30	/* seconds */
32#define WDT_SOFTTIMER_MAX	255	/* seconds */
33#define WDT_SOFTTIMER_THRESHOLD	60	/* seconds */
34
35static int timeout = WDT_DEFAULT_TIME;
36static bool nowayout = WATCHDOG_NOWAYOUT;
37
38module_param(timeout, int, 0);
39MODULE_PARM_DESC(timeout, "Watchdog time in seconds. (default="
40				__MODULE_STRING(WDT_DEFAULT_TIME) ")");
41
42module_param(nowayout, bool, 0);
43MODULE_PARM_DESC(nowayout,
44		"Watchdog cannot be stopped once started (default="
45				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
46
47static inline struct bcm47xx_wdt *bcm47xx_wdt_get(struct watchdog_device *wdd)
48{
49	return container_of(wdd, struct bcm47xx_wdt, wdd);
50}
51
52static int bcm47xx_wdt_hard_keepalive(struct watchdog_device *wdd)
53{
54	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
55
56	wdt->timer_set_ms(wdt, wdd->timeout * 1000);
57
58	return 0;
59}
60
61static int bcm47xx_wdt_hard_start(struct watchdog_device *wdd)
62{
63	return 0;
64}
65
66static int bcm47xx_wdt_hard_stop(struct watchdog_device *wdd)
67{
68	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
69
70	wdt->timer_set(wdt, 0);
71
72	return 0;
73}
74
75static int bcm47xx_wdt_hard_set_timeout(struct watchdog_device *wdd,
76					unsigned int new_time)
77{
78	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
79	u32 max_timer = wdt->max_timer_ms;
80
81	if (new_time < 1 || new_time > max_timer / 1000) {
82		pr_warn("timeout value must be 1<=x<=%d, using %d\n",
83			max_timer / 1000, new_time);
84		return -EINVAL;
85	}
86
87	wdd->timeout = new_time;
88	return 0;
89}
90
91static struct watchdog_ops bcm47xx_wdt_hard_ops = {
92	.owner		= THIS_MODULE,
93	.start		= bcm47xx_wdt_hard_start,
94	.stop		= bcm47xx_wdt_hard_stop,
95	.ping		= bcm47xx_wdt_hard_keepalive,
96	.set_timeout	= bcm47xx_wdt_hard_set_timeout,
97};
98
99static void bcm47xx_wdt_soft_timer_tick(unsigned long data)
100{
101	struct bcm47xx_wdt *wdt = (struct bcm47xx_wdt *)data;
102	u32 next_tick = min(wdt->wdd.timeout * 1000, wdt->max_timer_ms);
103
104	if (!atomic_dec_and_test(&wdt->soft_ticks)) {
105		wdt->timer_set_ms(wdt, next_tick);
106		mod_timer(&wdt->soft_timer, jiffies + HZ);
107	} else {
108		pr_crit("Watchdog will fire soon!!!\n");
109	}
110}
111
112static int bcm47xx_wdt_soft_keepalive(struct watchdog_device *wdd)
113{
114	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
115
116	atomic_set(&wdt->soft_ticks, wdd->timeout);
117
118	return 0;
119}
120
121static int bcm47xx_wdt_soft_start(struct watchdog_device *wdd)
122{
123	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
124
125	bcm47xx_wdt_soft_keepalive(wdd);
126	bcm47xx_wdt_soft_timer_tick((unsigned long)wdt);
127
128	return 0;
129}
130
131static int bcm47xx_wdt_soft_stop(struct watchdog_device *wdd)
132{
133	struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
134
135	del_timer_sync(&wdt->soft_timer);
136	wdt->timer_set(wdt, 0);
137
138	return 0;
139}
140
141static int bcm47xx_wdt_soft_set_timeout(struct watchdog_device *wdd,
142					unsigned int new_time)
143{
144	if (new_time < 1 || new_time > WDT_SOFTTIMER_MAX) {
145		pr_warn("timeout value must be 1<=x<=%d, using %d\n",
146			WDT_SOFTTIMER_MAX, new_time);
147		return -EINVAL;
148	}
149
150	wdd->timeout = new_time;
151	return 0;
152}
153
154static const struct watchdog_info bcm47xx_wdt_info = {
155	.identity	= DRV_NAME,
156	.options	= WDIOF_SETTIMEOUT |
157				WDIOF_KEEPALIVEPING |
158				WDIOF_MAGICCLOSE,
159};
160
161static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
162				  unsigned long code, void *unused)
163{
164	struct bcm47xx_wdt *wdt;
165
166	wdt = container_of(this, struct bcm47xx_wdt, notifier);
167	if (code == SYS_DOWN || code == SYS_HALT)
168		wdt->wdd.ops->stop(&wdt->wdd);
169	return NOTIFY_DONE;
170}
171
172static int bcm47xx_wdt_restart(struct notifier_block *this, unsigned long mode,
173			       void *cmd)
174{
175	struct bcm47xx_wdt *wdt;
176
177	wdt = container_of(this, struct bcm47xx_wdt, restart_handler);
178	wdt->timer_set(wdt, 1);
179
180	return NOTIFY_DONE;
181}
182
183static struct watchdog_ops bcm47xx_wdt_soft_ops = {
184	.owner		= THIS_MODULE,
185	.start		= bcm47xx_wdt_soft_start,
186	.stop		= bcm47xx_wdt_soft_stop,
187	.ping		= bcm47xx_wdt_soft_keepalive,
188	.set_timeout	= bcm47xx_wdt_soft_set_timeout,
189};
190
191static int bcm47xx_wdt_probe(struct platform_device *pdev)
192{
193	int ret;
194	bool soft;
195	struct bcm47xx_wdt *wdt = dev_get_platdata(&pdev->dev);
196
197	if (!wdt)
198		return -ENXIO;
199
200	soft = wdt->max_timer_ms < WDT_SOFTTIMER_THRESHOLD * 1000;
201
202	if (soft) {
203		wdt->wdd.ops = &bcm47xx_wdt_soft_ops;
204		setup_timer(&wdt->soft_timer, bcm47xx_wdt_soft_timer_tick,
205			    (long unsigned int)wdt);
206	} else {
207		wdt->wdd.ops = &bcm47xx_wdt_hard_ops;
208	}
209
210	wdt->wdd.info = &bcm47xx_wdt_info;
211	wdt->wdd.timeout = WDT_DEFAULT_TIME;
212	wdt->wdd.parent = &pdev->dev;
213	ret = wdt->wdd.ops->set_timeout(&wdt->wdd, timeout);
214	if (ret)
215		goto err_timer;
216	watchdog_set_nowayout(&wdt->wdd, nowayout);
217
218	wdt->notifier.notifier_call = &bcm47xx_wdt_notify_sys;
219
220	ret = register_reboot_notifier(&wdt->notifier);
221	if (ret)
222		goto err_timer;
223
224	wdt->restart_handler.notifier_call = &bcm47xx_wdt_restart;
225	wdt->restart_handler.priority = 64;
226	ret = register_restart_handler(&wdt->restart_handler);
227	if (ret)
228		goto err_notifier;
229
230	ret = watchdog_register_device(&wdt->wdd);
231	if (ret)
232		goto err_handler;
233
234	dev_info(&pdev->dev, "BCM47xx Watchdog Timer enabled (%d seconds%s%s)\n",
235		timeout, nowayout ? ", nowayout" : "",
236		soft ? ", Software Timer" : "");
237	return 0;
238
239err_handler:
240	unregister_restart_handler(&wdt->restart_handler);
241err_notifier:
242	unregister_reboot_notifier(&wdt->notifier);
243err_timer:
244	if (soft)
245		del_timer_sync(&wdt->soft_timer);
246
247	return ret;
248}
249
250static int bcm47xx_wdt_remove(struct platform_device *pdev)
251{
252	struct bcm47xx_wdt *wdt = dev_get_platdata(&pdev->dev);
253
254	if (!wdt)
255		return -ENXIO;
256
257	watchdog_unregister_device(&wdt->wdd);
258	unregister_reboot_notifier(&wdt->notifier);
259
260	return 0;
261}
262
263static struct platform_driver bcm47xx_wdt_driver = {
264	.driver		= {
265		.name	= "bcm47xx-wdt",
266	},
267	.probe		= bcm47xx_wdt_probe,
268	.remove		= bcm47xx_wdt_remove,
269};
270
271module_platform_driver(bcm47xx_wdt_driver);
272
273MODULE_AUTHOR("Aleksandar Radovanovic");
274MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
275MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
276MODULE_LICENSE("GPL");
277