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/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 #include <linux/io.h> 50 #include <linux/uaccess.h> 51 #include <linux/gpio.h> 52 53 #include <asm/mach-au1x00/au1000.h> 54 55 #define MTX1_WDT_INTERVAL (5 * HZ) 56 57 static int ticks = 100 * HZ; 58 59 static struct { 60 struct completion stop; 61 spinlock_t lock; 62 int running; 63 struct timer_list timer; 64 int queue; 65 int default_ticks; 66 unsigned long inuse; 67 unsigned gpio; 68 unsigned int gstate; 69 } mtx1_wdt_device; 70 71 static void mtx1_wdt_trigger(struct timer_list *unused) 72 { 73 spin_lock(&mtx1_wdt_device.lock); 74 if (mtx1_wdt_device.running) 75 ticks--; 76 77 /* toggle wdt gpio */ 78 mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate; 79 gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate); 80 81 if (mtx1_wdt_device.queue && ticks) 82 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); 83 else 84 complete(&mtx1_wdt_device.stop); 85 spin_unlock(&mtx1_wdt_device.lock); 86 } 87 88 static void mtx1_wdt_reset(void) 89 { 90 ticks = mtx1_wdt_device.default_ticks; 91 } 92 93 94 static void mtx1_wdt_start(void) 95 { 96 unsigned long flags; 97 98 spin_lock_irqsave(&mtx1_wdt_device.lock, flags); 99 if (!mtx1_wdt_device.queue) { 100 mtx1_wdt_device.queue = 1; 101 mtx1_wdt_device.gstate = 1; 102 gpio_set_value(mtx1_wdt_device.gpio, 1); 103 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); 104 } 105 mtx1_wdt_device.running++; 106 spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags); 107 } 108 109 static int mtx1_wdt_stop(void) 110 { 111 unsigned long flags; 112 113 spin_lock_irqsave(&mtx1_wdt_device.lock, flags); 114 if (mtx1_wdt_device.queue) { 115 mtx1_wdt_device.queue = 0; 116 mtx1_wdt_device.gstate = 0; 117 gpio_set_value(mtx1_wdt_device.gpio, 0); 118 } 119 ticks = mtx1_wdt_device.default_ticks; 120 spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags); 121 return 0; 122 } 123 124 /* Filesystem functions */ 125 126 static int mtx1_wdt_open(struct inode *inode, struct file *file) 127 { 128 if (test_and_set_bit(0, &mtx1_wdt_device.inuse)) 129 return -EBUSY; 130 return nonseekable_open(inode, file); 131 } 132 133 134 static int mtx1_wdt_release(struct inode *inode, struct file *file) 135 { 136 clear_bit(0, &mtx1_wdt_device.inuse); 137 return 0; 138 } 139 140 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd, 141 unsigned long arg) 142 { 143 void __user *argp = (void __user *)arg; 144 int __user *p = (int __user *)argp; 145 unsigned int value; 146 static const struct watchdog_info ident = { 147 .options = WDIOF_CARDRESET, 148 .identity = "MTX-1 WDT", 149 }; 150 151 switch (cmd) { 152 case WDIOC_GETSUPPORT: 153 if (copy_to_user(argp, &ident, sizeof(ident))) 154 return -EFAULT; 155 break; 156 case WDIOC_GETSTATUS: 157 case WDIOC_GETBOOTSTATUS: 158 put_user(0, p); 159 break; 160 case WDIOC_SETOPTIONS: 161 if (get_user(value, p)) 162 return -EFAULT; 163 if (value & WDIOS_ENABLECARD) 164 mtx1_wdt_start(); 165 else if (value & WDIOS_DISABLECARD) 166 mtx1_wdt_stop(); 167 else 168 return -EINVAL; 169 return 0; 170 case WDIOC_KEEPALIVE: 171 mtx1_wdt_reset(); 172 break; 173 default: 174 return -ENOTTY; 175 } 176 return 0; 177 } 178 179 180 static ssize_t mtx1_wdt_write(struct file *file, const char *buf, 181 size_t count, loff_t *ppos) 182 { 183 if (!count) 184 return -EIO; 185 mtx1_wdt_reset(); 186 return count; 187 } 188 189 static const struct file_operations mtx1_wdt_fops = { 190 .owner = THIS_MODULE, 191 .llseek = no_llseek, 192 .unlocked_ioctl = mtx1_wdt_ioctl, 193 .open = mtx1_wdt_open, 194 .write = mtx1_wdt_write, 195 .release = mtx1_wdt_release, 196 }; 197 198 199 static struct miscdevice mtx1_wdt_misc = { 200 .minor = WATCHDOG_MINOR, 201 .name = "watchdog", 202 .fops = &mtx1_wdt_fops, 203 }; 204 205 206 static int mtx1_wdt_probe(struct platform_device *pdev) 207 { 208 int ret; 209 210 mtx1_wdt_device.gpio = pdev->resource[0].start; 211 ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio, 212 GPIOF_OUT_INIT_HIGH, "mtx1-wdt"); 213 if (ret < 0) { 214 dev_err(&pdev->dev, "failed to request gpio"); 215 return ret; 216 } 217 218 spin_lock_init(&mtx1_wdt_device.lock); 219 init_completion(&mtx1_wdt_device.stop); 220 mtx1_wdt_device.queue = 0; 221 clear_bit(0, &mtx1_wdt_device.inuse); 222 timer_setup(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0); 223 mtx1_wdt_device.default_ticks = ticks; 224 225 ret = misc_register(&mtx1_wdt_misc); 226 if (ret < 0) { 227 dev_err(&pdev->dev, "failed to register\n"); 228 return ret; 229 } 230 mtx1_wdt_start(); 231 dev_info(&pdev->dev, "MTX-1 Watchdog driver\n"); 232 return 0; 233 } 234 235 static int mtx1_wdt_remove(struct platform_device *pdev) 236 { 237 /* FIXME: do we need to lock this test ? */ 238 if (mtx1_wdt_device.queue) { 239 mtx1_wdt_device.queue = 0; 240 wait_for_completion(&mtx1_wdt_device.stop); 241 } 242 243 misc_deregister(&mtx1_wdt_misc); 244 return 0; 245 } 246 247 static struct platform_driver mtx1_wdt_driver = { 248 .probe = mtx1_wdt_probe, 249 .remove = mtx1_wdt_remove, 250 .driver.name = "mtx1-wdt", 251 .driver.owner = THIS_MODULE, 252 }; 253 254 module_platform_driver(mtx1_wdt_driver); 255 256 MODULE_AUTHOR("Michael Stickel, Florian Fainelli"); 257 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog"); 258 MODULE_LICENSE("GPL"); 259 MODULE_ALIAS("platform:mtx1-wdt"); 260