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 <linux/platform_device.h> 49 50 #include <asm/io.h> 51 #include <asm/uaccess.h> 52 53 #include <asm/mach-au1x00/au1000.h> 54 #include <asm/gpio.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 int running; 63 struct timer_list timer; 64 int queue; 65 int default_ticks; 66 unsigned long inuse; 67 unsigned gpio; 68 } mtx1_wdt_device; 69 70 static void mtx1_wdt_trigger(unsigned long unused) 71 { 72 u32 tmp; 73 74 if (mtx1_wdt_device.running) 75 ticks--; 76 /* 77 * toggle GPIO2_15 78 */ 79 tmp = au_readl(GPIO2_DIR); 80 tmp = (tmp & ~(1 << mtx1_wdt_device.gpio)) | 81 ((~tmp) & (1 << mtx1_wdt_device.gpio)); 82 au_writel (tmp, GPIO2_DIR); 83 84 if (mtx1_wdt_device.queue && ticks) 85 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); 86 else { 87 complete(&mtx1_wdt_device.stop); 88 } 89 } 90 91 static void mtx1_wdt_reset(void) 92 { 93 ticks = mtx1_wdt_device.default_ticks; 94 } 95 96 97 static void mtx1_wdt_start(void) 98 { 99 if (!mtx1_wdt_device.queue) { 100 mtx1_wdt_device.queue = 1; 101 gpio_set_value(mtx1_wdt_device.gpio, 1); 102 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); 103 } 104 mtx1_wdt_device.running++; 105 } 106 107 static int mtx1_wdt_stop(void) 108 { 109 if (mtx1_wdt_device.queue) { 110 mtx1_wdt_device.queue = 0; 111 gpio_set_value(mtx1_wdt_device.gpio, 0); 112 } 113 114 ticks = mtx1_wdt_device.default_ticks; 115 116 return 0; 117 } 118 119 /* Filesystem functions */ 120 121 static int mtx1_wdt_open(struct inode *inode, struct file *file) 122 { 123 if (test_and_set_bit(0, &mtx1_wdt_device.inuse)) 124 return -EBUSY; 125 126 return nonseekable_open(inode, file); 127 } 128 129 130 static int mtx1_wdt_release(struct inode *inode, struct file *file) 131 { 132 clear_bit(0, &mtx1_wdt_device.inuse); 133 return 0; 134 } 135 136 static int mtx1_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) 137 { 138 void __user *argp = (void __user *)arg; 139 unsigned int value; 140 static struct watchdog_info ident = 141 { 142 .options = WDIOF_CARDRESET, 143 .identity = "MTX-1 WDT", 144 }; 145 146 switch(cmd) { 147 case WDIOC_KEEPALIVE: 148 mtx1_wdt_reset(); 149 break; 150 case WDIOC_GETSTATUS: 151 case WDIOC_GETBOOTSTATUS: 152 if ( copy_to_user(argp, &value, sizeof(int)) ) 153 return -EFAULT; 154 break; 155 case WDIOC_GETSUPPORT: 156 if ( copy_to_user(argp, &ident, sizeof(ident)) ) 157 return -EFAULT; 158 break; 159 case WDIOC_SETOPTIONS: 160 if ( copy_from_user(&value, argp, sizeof(int)) ) 161 return -EFAULT; 162 switch(value) { 163 case WDIOS_ENABLECARD: 164 mtx1_wdt_start(); 165 break; 166 case WDIOS_DISABLECARD: 167 return mtx1_wdt_stop(); 168 default: 169 return -EINVAL; 170 } 171 break; 172 default: 173 return -ENOTTY; 174 } 175 return 0; 176 } 177 178 179 static ssize_t mtx1_wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos) 180 { 181 if (!count) 182 return -EIO; 183 184 mtx1_wdt_reset(); 185 return count; 186 } 187 188 static const struct file_operations mtx1_wdt_fops = { 189 .owner = THIS_MODULE, 190 .llseek = no_llseek, 191 .ioctl = mtx1_wdt_ioctl, 192 .open = mtx1_wdt_open, 193 .write = mtx1_wdt_write, 194 .release = mtx1_wdt_release 195 }; 196 197 198 static struct miscdevice mtx1_wdt_misc = { 199 .minor = WATCHDOG_MINOR, 200 .name = "watchdog", 201 .fops = &mtx1_wdt_fops 202 }; 203 204 205 static int mtx1_wdt_probe(struct platform_device *pdev) 206 { 207 int ret; 208 209 mtx1_wdt_device.gpio = pdev->resource[0].start; 210 211 if ((ret = misc_register(&mtx1_wdt_misc)) < 0) { 212 printk(KERN_ERR " mtx-1_wdt : failed to register\n"); 213 return ret; 214 } 215 216 init_completion(&mtx1_wdt_device.stop); 217 mtx1_wdt_device.queue = 0; 218 219 clear_bit(0, &mtx1_wdt_device.inuse); 220 221 setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L); 222 223 mtx1_wdt_device.default_ticks = ticks; 224 225 mtx1_wdt_start(); 226 227 printk(KERN_INFO "MTX-1 Watchdog driver\n"); 228 229 return 0; 230 } 231 232 static int mtx1_wdt_remove(struct platform_device *pdev) 233 { 234 if (mtx1_wdt_device.queue) { 235 mtx1_wdt_device.queue = 0; 236 wait_for_completion(&mtx1_wdt_device.stop); 237 } 238 misc_deregister(&mtx1_wdt_misc); 239 return 0; 240 } 241 242 static struct platform_driver mtx1_wdt = { 243 .probe = mtx1_wdt_probe, 244 .remove = mtx1_wdt_remove, 245 .driver.name = "mtx1-wdt", 246 }; 247 248 static int __init mtx1_wdt_init(void) 249 { 250 return platform_driver_register(&mtx1_wdt); 251 } 252 253 static void __exit mtx1_wdt_exit(void) 254 { 255 platform_driver_unregister(&mtx1_wdt); 256 } 257 258 module_init(mtx1_wdt_init); 259 module_exit(mtx1_wdt_exit); 260 261 MODULE_AUTHOR("Michael Stickel, Florian Fainelli"); 262 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog"); 263 MODULE_LICENSE("GPL"); 264 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 265