Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

Linux/drivers/watchdog/mtx-1_wdt.c

  1 /*
  2  *      Driver for the MTX-1 Watchdog.
  3  *
  4  *      (C) Copyright 2005 4G Systems <info@4g-systems.biz>,
  5  *                                                      All Rights Reserved.
  6  *                              http://www.4g-systems.biz
  7  *
  8  *      (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
  9  *
 10  *      This program is free software; you can redistribute it and/or
 11  *      modify it under the terms of the GNU General Public License
 12  *      as published by the Free Software Foundation; either version
 13  *      2 of the License, or (at your option) any later version.
 14  *
 15  *      Neither Michael Stickel nor 4G Systems admit liability nor provide
 16  *      warranty for any of this software. This material is provided
 17  *      "AS-IS" and at no charge.
 18  *
 19  *      (c) Copyright 2005    4G Systems <info@4g-systems.biz>
 20  *
 21  *      Release 0.01.
 22  *      Author: Michael Stickel  michael.stickel@4g-systems.biz
 23  *
 24  *      Release 0.02.
 25  *      Author: Florian Fainelli florian@openwrt.org
 26  *              use the Linux watchdog/timer APIs
 27  *
 28  *      The Watchdog is configured to reset the MTX-1
 29  *      if it is not triggered for 100 seconds.
 30  *      It should not be triggered more often than 1.6 seconds.
 31  *
 32  *      A timer triggers the watchdog every 5 seconds, until
 33  *      it is opened for the first time. After the first open
 34  *      it MUST be triggered every 2..95 seconds.
 35  */
 36 
 37 #include <linux/module.h>
 38 #include <linux/moduleparam.h>
 39 #include <linux/types.h>
 40 #include <linux/errno.h>
 41 #include <linux/miscdevice.h>
 42 #include <linux/fs.h>
 43 #include <linux/init.h>
 44 #include <linux/ioport.h>
 45 #include <linux/timer.h>
 46 #include <linux/completion.h>
 47 #include <linux/jiffies.h>
 48 #include <linux/watchdog.h>
 49 #include <linux/platform_device.h>
 50 #include <linux/io.h>
 51 #include <linux/uaccess.h>
 52 #include <linux/gpio.h>
 53 
 54 #include <asm/mach-au1x00/au1000.h>
 55 
 56 #define MTX1_WDT_INTERVAL       (5 * HZ)
 57 
 58 static int ticks = 100 * HZ;
 59 
 60 static struct {
 61         struct completion stop;
 62         spinlock_t lock;
 63         int running;
 64         struct timer_list timer;
 65         int queue;
 66         int default_ticks;
 67         unsigned long inuse;
 68         unsigned gpio;
 69         unsigned int gstate;
 70 } mtx1_wdt_device;
 71 
 72 static void mtx1_wdt_trigger(unsigned long unused)
 73 {
 74         spin_lock(&mtx1_wdt_device.lock);
 75         if (mtx1_wdt_device.running)
 76                 ticks--;
 77 
 78         /* toggle wdt gpio */
 79         mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
 80         gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
 81 
 82         if (mtx1_wdt_device.queue && ticks)
 83                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
 84         else
 85                 complete(&mtx1_wdt_device.stop);
 86         spin_unlock(&mtx1_wdt_device.lock);
 87 }
 88 
 89 static void mtx1_wdt_reset(void)
 90 {
 91         ticks = mtx1_wdt_device.default_ticks;
 92 }
 93 
 94 
 95 static void mtx1_wdt_start(void)
 96 {
 97         unsigned long flags;
 98 
 99         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
100         if (!mtx1_wdt_device.queue) {
101                 mtx1_wdt_device.queue = 1;
102                 mtx1_wdt_device.gstate = 1;
103                 gpio_set_value(mtx1_wdt_device.gpio, 1);
104                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
105         }
106         mtx1_wdt_device.running++;
107         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
108 }
109 
110 static int mtx1_wdt_stop(void)
111 {
112         unsigned long flags;
113 
114         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
115         if (mtx1_wdt_device.queue) {
116                 mtx1_wdt_device.queue = 0;
117                 mtx1_wdt_device.gstate = 0;
118                 gpio_set_value(mtx1_wdt_device.gpio, 0);
119         }
120         ticks = mtx1_wdt_device.default_ticks;
121         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
122         return 0;
123 }
124 
125 /* Filesystem functions */
126 
127 static int mtx1_wdt_open(struct inode *inode, struct file *file)
128 {
129         if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
130                 return -EBUSY;
131         return nonseekable_open(inode, file);
132 }
133 
134 
135 static int mtx1_wdt_release(struct inode *inode, struct file *file)
136 {
137         clear_bit(0, &mtx1_wdt_device.inuse);
138         return 0;
139 }
140 
141 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
142                                                         unsigned long arg)
143 {
144         void __user *argp = (void __user *)arg;
145         int __user *p = (int __user *)argp;
146         unsigned int value;
147         static const struct watchdog_info ident = {
148                 .options = WDIOF_CARDRESET,
149                 .identity = "MTX-1 WDT",
150         };
151 
152         switch (cmd) {
153         case WDIOC_GETSUPPORT:
154                 if (copy_to_user(argp, &ident, sizeof(ident)))
155                         return -EFAULT;
156                 break;
157         case WDIOC_GETSTATUS:
158         case WDIOC_GETBOOTSTATUS:
159                 put_user(0, p);
160                 break;
161         case WDIOC_SETOPTIONS:
162                 if (get_user(value, p))
163                         return -EFAULT;
164                 if (value & WDIOS_ENABLECARD)
165                         mtx1_wdt_start();
166                 else if (value & WDIOS_DISABLECARD)
167                         mtx1_wdt_stop();
168                 else
169                         return -EINVAL;
170                 return 0;
171         case WDIOC_KEEPALIVE:
172                 mtx1_wdt_reset();
173                 break;
174         default:
175                 return -ENOTTY;
176         }
177         return 0;
178 }
179 
180 
181 static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
182                                                 size_t count, loff_t *ppos)
183 {
184         if (!count)
185                 return -EIO;
186         mtx1_wdt_reset();
187         return count;
188 }
189 
190 static const struct file_operations mtx1_wdt_fops = {
191         .owner          = THIS_MODULE,
192         .llseek         = no_llseek,
193         .unlocked_ioctl = mtx1_wdt_ioctl,
194         .open           = mtx1_wdt_open,
195         .write          = mtx1_wdt_write,
196         .release        = mtx1_wdt_release,
197 };
198 
199 
200 static struct miscdevice mtx1_wdt_misc = {
201         .minor  = WATCHDOG_MINOR,
202         .name   = "watchdog",
203         .fops   = &mtx1_wdt_fops,
204 };
205 
206 
207 static int mtx1_wdt_probe(struct platform_device *pdev)
208 {
209         int ret;
210 
211         mtx1_wdt_device.gpio = pdev->resource[0].start;
212         ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
213                                 GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
214         if (ret < 0) {
215                 dev_err(&pdev->dev, "failed to request gpio");
216                 return ret;
217         }
218 
219         spin_lock_init(&mtx1_wdt_device.lock);
220         init_completion(&mtx1_wdt_device.stop);
221         mtx1_wdt_device.queue = 0;
222         clear_bit(0, &mtx1_wdt_device.inuse);
223         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
224         mtx1_wdt_device.default_ticks = ticks;
225 
226         ret = misc_register(&mtx1_wdt_misc);
227         if (ret < 0) {
228                 dev_err(&pdev->dev, "failed to register\n");
229                 return ret;
230         }
231         mtx1_wdt_start();
232         dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
233         return 0;
234 }
235 
236 static int mtx1_wdt_remove(struct platform_device *pdev)
237 {
238         /* FIXME: do we need to lock this test ? */
239         if (mtx1_wdt_device.queue) {
240                 mtx1_wdt_device.queue = 0;
241                 wait_for_completion(&mtx1_wdt_device.stop);
242         }
243 
244         misc_deregister(&mtx1_wdt_misc);
245         return 0;
246 }
247 
248 static struct platform_driver mtx1_wdt_driver = {
249         .probe = mtx1_wdt_probe,
250         .remove = mtx1_wdt_remove,
251         .driver.name = "mtx1-wdt",
252         .driver.owner = THIS_MODULE,
253 };
254 
255 module_platform_driver(mtx1_wdt_driver);
256 
257 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
258 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
259 MODULE_LICENSE("GPL");
260 MODULE_ALIAS("platform:mtx1-wdt");
261 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us