1 /* 2 * Driver for the MTX-1 Watchdog. 3 * 4 * (C) Copyright 2005 4G Systems <info@4g-systems.biz>, All Rights Reserved. 5 * http://www.4g-systems.biz 6 * 7 * (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org> 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 * 14 * Neither Michael Stickel nor 4G Systems admit liability nor provide 15 * warranty for any of this software. This material is provided 16 * "AS-IS" and at no charge. 17 * 18 * (c) Copyright 2005 4G Systems <info@4g-systems.biz> 19 * 20 * Release 0.01. 21 * Author: Michael Stickel michael.stickel@4g-systems.biz 22 * 23 * Release 0.02. 24 * Author: Florian Fainelli florian@openwrt.org 25 * use the Linux watchdog/timer APIs 26 * 27 * The Watchdog is configured to reset the MTX-1 28 * if it is not triggered for 100 seconds. 29 * It should not be triggered more often than 1.6 seconds. 30 * 31 * A timer triggers the watchdog every 5 seconds, until 32 * it is opened for the first time. After the first open 33 * it MUST be triggered every 2..95 seconds. 34 */ 35 36 #include <linux/module.h> 37 #include <linux/moduleparam.h> 38 #include <linux/types.h> 39 #include <linux/errno.h> 40 #include <linux/miscdevice.h> 41 #include <linux/fs.h> 42 #include <linux/init.h> 43 #include <linux/ioport.h> 44 #include <linux/timer.h> 45 #include <linux/completion.h> 46 #include <linux/jiffies.h> 47 #include <linux/watchdog.h> 48 #include <asm/io.h> 49 #include <asm/uaccess.h> 50 51 #include <asm/mach-au1x00/au1000.h> 52 53 #define MTX1_WDT_INTERVAL (5 * HZ) 54 55 static int ticks = 100 * HZ; 56 57 static struct { 58 struct completion stop; 59 volatile int running; 60 struct timer_list timer; 61 volatile int queue; 62 int default_ticks; 63 unsigned long inuse; 64 } mtx1_wdt_device; 65 66 static void mtx1_wdt_trigger(unsigned long unused) 67 { 68 u32 tmp; 69 70 if (mtx1_wdt_device.running) 71 ticks--; 72 /* 73 * toggle GPIO2_15 74 */ 75 tmp = au_readl(GPIO2_DIR); 76 tmp = (tmp & ~(1<<15)) | ((~tmp) & (1<<15)); 77 au_writel (tmp, GPIO2_DIR); 78 79 if (mtx1_wdt_device.queue && ticks) 80 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); 81 else { 82 complete(&mtx1_wdt_device.stop); 83 } 84 } 85 86 static void mtx1_wdt_reset(void) 87 { 88 ticks = mtx1_wdt_device.default_ticks; 89 } 90 91 92 static void mtx1_wdt_start(void) 93 { 94 if (!mtx1_wdt_device.queue) { 95 mtx1_wdt_device.queue = 1; 96 au_writel (au_readl(GPIO2_DIR) | (u32)(1<<15), GPIO2_DIR); 97 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); 98 } 99 mtx1_wdt_device.running++; 100 } 101 102 static int mtx1_wdt_stop(void) 103 { 104 if (mtx1_wdt_device.queue) { 105 mtx1_wdt_device.queue = 0; 106 au_writel (au_readl(GPIO2_DIR) & ~((u32)(1<<15)), GPIO2_DIR); 107 } 108 109 ticks = mtx1_wdt_device.default_ticks; 110 111 return 0; 112 } 113 114 /* Filesystem functions */ 115 116 static int mtx1_wdt_open(struct inode *inode, struct file *file) 117 { 118 if (test_and_set_bit(0, &mtx1_wdt_device.inuse)) 119 return -EBUSY; 120 121 return nonseekable_open(inode, file); 122 } 123 124 125 static int mtx1_wdt_release(struct inode *inode, struct file *file) 126 { 127 clear_bit(0, &mtx1_wdt_device.inuse); 128 return 0; 129 } 130 131 static int mtx1_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) 132 { 133 void __user *argp = (void __user *)arg; 134 unsigned int value; 135 static struct watchdog_info ident = 136 { 137 .options = WDIOF_CARDRESET, 138 .identity = "MTX-1 WDT", 139 }; 140 141 switch(cmd) { 142 case WDIOC_KEEPALIVE: 143 mtx1_wdt_reset(); 144 break; 145 case WDIOC_GETSTATUS: 146 case WDIOC_GETBOOTSTATUS: 147 if ( copy_to_user(argp, &value, sizeof(int)) ) 148 return -EFAULT; 149 break; 150 case WDIOC_GETSUPPORT: 151 if ( copy_to_user(argp, &ident, sizeof(ident)) ) 152 return -EFAULT; 153 break; 154 case WDIOC_SETOPTIONS: 155 if ( copy_from_user(&value, argp, sizeof(int)) ) 156 return -EFAULT; 157 switch(value) { 158 case WDIOS_ENABLECARD: 159 mtx1_wdt_start(); 160 break; 161 case WDIOS_DISABLECARD: 162 return mtx1_wdt_stop(); 163 default: 164 return -EINVAL; 165 } 166 break; 167 default: 168 return -ENOTTY; 169 } 170 return 0; 171 } 172 173 174 static ssize_t mtx1_wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos) 175 { 176 if (!count) 177 return -EIO; 178 179 mtx1_wdt_reset(); 180 return count; 181 } 182 183 static const struct file_operations mtx1_wdt_fops = { 184 .owner = THIS_MODULE, 185 .llseek = no_llseek, 186 .ioctl = mtx1_wdt_ioctl, 187 .open = mtx1_wdt_open, 188 .write = mtx1_wdt_write, 189 .release = mtx1_wdt_release 190 }; 191 192 193 static struct miscdevice mtx1_wdt_misc = { 194 .minor = WATCHDOG_MINOR, 195 .name = "watchdog", 196 .fops = &mtx1_wdt_fops 197 }; 198 199 200 static int __init mtx1_wdt_init(void) 201 { 202 int ret; 203 204 if ((ret = misc_register(&mtx1_wdt_misc)) < 0) { 205 printk(KERN_ERR " mtx-1_wdt : failed to register\n"); 206 return ret; 207 } 208 209 init_completion(&mtx1_wdt_device.stop); 210 mtx1_wdt_device.queue = 0; 211 212 clear_bit(0, &mtx1_wdt_device.inuse); 213 214 setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L); 215 216 mtx1_wdt_device.default_ticks = ticks; 217 218 mtx1_wdt_start(); 219 220 printk(KERN_INFO "MTX-1 Watchdog driver\n"); 221 222 return 0; 223 } 224 225 static void __exit mtx1_wdt_exit(void) 226 { 227 if (mtx1_wdt_device.queue) { 228 mtx1_wdt_device.queue = 0; 229 wait_for_completion(&mtx1_wdt_device.stop); 230 } 231 misc_deregister(&mtx1_wdt_misc); 232 } 233 234 module_init(mtx1_wdt_init); 235 module_exit(mtx1_wdt_exit); 236 237 MODULE_AUTHOR("Michael Stickel, Florian Fainelli"); 238 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog"); 239 MODULE_LICENSE("GPL"); 240