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 } mtx1_wdt_device; 70 71 static void mtx1_wdt_trigger(unsigned long unused) 72 { 73 u32 tmp; 74 75 spin_lock(&mtx1_wdt_device.lock); 76 if (mtx1_wdt_device.running) 77 ticks--; 78 /* 79 * toggle GPIO2_15 80 */ 81 tmp = au_readl(GPIO2_DIR); 82 tmp = (tmp & ~(1 << mtx1_wdt_device.gpio)) | 83 ((~tmp) & (1 << mtx1_wdt_device.gpio)); 84 au_writel(tmp, GPIO2_DIR); 85 86 if (mtx1_wdt_device.queue && ticks) 87 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); 88 else 89 complete(&mtx1_wdt_device.stop); 90 spin_unlock(&mtx1_wdt_device.lock); 91 } 92 93 static void mtx1_wdt_reset(void) 94 { 95 ticks = mtx1_wdt_device.default_ticks; 96 } 97 98 99 static void mtx1_wdt_start(void) 100 { 101 spin_lock_irqsave(&mtx1_wdt_device.lock, flags); 102 if (!mtx1_wdt_device.queue) { 103 mtx1_wdt_device.queue = 1; 104 gpio_set_value(mtx1_wdt_device.gpio, 1); 105 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); 106 } 107 mtx1_wdt_device.running++; 108 spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags); 109 } 110 111 static int mtx1_wdt_stop(void) 112 { 113 spin_lock_irqsave(&mtx1_wdt_device.lock, flags); 114 if (mtx1_wdt_device.queue) { 115 mtx1_wdt_device.queue = 0; 116 gpio_set_value(mtx1_wdt_device.gpio, 0); 117 } 118 ticks = mtx1_wdt_device.default_ticks; 119 spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags); 120 return 0; 121 } 122 123 /* Filesystem functions */ 124 125 static int mtx1_wdt_open(struct inode *inode, struct file *file) 126 { 127 if (test_and_set_bit(0, &mtx1_wdt_device.inuse)) 128 return -EBUSY; 129 return nonseekable_open(inode, file); 130 } 131 132 133 static int mtx1_wdt_release(struct inode *inode, struct file *file) 134 { 135 clear_bit(0, &mtx1_wdt_device.inuse); 136 return 0; 137 } 138 139 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd, 140 unsigned long arg) 141 { 142 void __user *argp = (void __user *)arg; 143 int __user *p = (int __user *)argp; 144 unsigned int value; 145 static const struct watchdog_info ident = { 146 .options = WDIOF_CARDRESET, 147 .identity = "MTX-1 WDT", 148 }; 149 150 switch (cmd) { 151 case WDIOC_GETSUPPORT: 152 if (copy_to_user(argp, &ident, sizeof(ident))) 153 return -EFAULT; 154 break; 155 case WDIOC_GETSTATUS: 156 case WDIOC_GETBOOTSTATUS: 157 put_user(0, p); 158 break; 159 case WDIOC_SETOPTIONS: 160 if (get_user(value, p)) 161 return -EFAULT; 162 if (value & WDIOS_ENABLECARD) 163 mtx1_wdt_start(); 164 else if (value & WDIOS_DISABLECARD) 165 mtx1_wdt_stop(); 166 else 167 return -EINVAL; 168 return 0; 169 case WDIOC_KEEPALIVE: 170 mtx1_wdt_reset(); 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, 180 size_t count, loff_t *ppos) 181 { 182 if (!count) 183 return -EIO; 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 .unlocked_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 spin_lock_init(&mtx1_wdt_device.lock); 212 init_completion(&mtx1_wdt_device.stop); 213 mtx1_wdt_device.queue = 0; 214 clear_bit(0, &mtx1_wdt_device.inuse); 215 setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L); 216 mtx1_wdt_device.default_ticks = ticks; 217 218 ret = misc_register(&mtx1_wdt_misc); 219 if (ret < 0) { 220 printk(KERN_ERR " mtx-1_wdt : failed to register\n"); 221 return ret; 222 } 223 mtx1_wdt_start(); 224 printk(KERN_INFO "MTX-1 Watchdog driver\n"); 225 return 0; 226 } 227 228 static int mtx1_wdt_remove(struct platform_device *pdev) 229 { 230 /* FIXME: do we need to lock this test ? */ 231 if (mtx1_wdt_device.queue) { 232 mtx1_wdt_device.queue = 0; 233 wait_for_completion(&mtx1_wdt_device.stop); 234 } 235 misc_deregister(&mtx1_wdt_misc); 236 return 0; 237 } 238 239 static struct platform_driver mtx1_wdt = { 240 .probe = mtx1_wdt_probe, 241 .remove = mtx1_wdt_remove, 242 .driver.name = "mtx1-wdt", 243 .driver.owner = THIS_MODULE, 244 }; 245 246 static int __init mtx1_wdt_init(void) 247 { 248 return platform_driver_register(&mtx1_wdt); 249 } 250 251 static void __exit mtx1_wdt_exit(void) 252 { 253 platform_driver_unregister(&mtx1_wdt); 254 } 255 256 module_init(mtx1_wdt_init); 257 module_exit(mtx1_wdt_exit); 258 259 MODULE_AUTHOR("Michael Stickel, Florian Fainelli"); 260 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog"); 261 MODULE_LICENSE("GPL"); 262 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 263 MODULE_ALIAS("platform:mtx1-wdt"); 264