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Linux/drivers/watchdog/bcm47xx_wdt.c

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

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