1 /* 2 * drivers/char/watchdog/ixp4xx_wdt.c 3 * 4 * Watchdog driver for Intel IXP4xx network processors 5 * 6 * Author: Deepak Saxena <dsaxena@plexity.net> 7 * 8 * Copyright 2004 (c) MontaVista, Software, Inc. 9 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> 10 * 11 * This file is licensed under the terms of the GNU General Public 12 * License version 2. This program is licensed "as is" without any 13 * warranty of any kind, whether express or implied. 14 */ 15 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/types.h> 19 #include <linux/kernel.h> 20 #include <linux/fs.h> 21 #include <linux/miscdevice.h> 22 #include <linux/watchdog.h> 23 #include <linux/init.h> 24 #include <linux/bitops.h> 25 #include <linux/uaccess.h> 26 #include <mach/hardware.h> 27 28 static int nowayout = WATCHDOG_NOWAYOUT; 29 static int heartbeat = 60; /* (secs) Default is 1 minute */ 30 static unsigned long wdt_status; 31 static unsigned long boot_status; 32 static DEFINE_SPINLOCK(wdt_lock); 33 34 #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL) 35 36 #define WDT_IN_USE 0 37 #define WDT_OK_TO_CLOSE 1 38 39 static void wdt_enable(void) 40 { 41 spin_lock(&wdt_lock); 42 *IXP4XX_OSWK = IXP4XX_WDT_KEY; 43 *IXP4XX_OSWE = 0; 44 *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat; 45 *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE; 46 *IXP4XX_OSWK = 0; 47 spin_unlock(&wdt_lock); 48 } 49 50 static void wdt_disable(void) 51 { 52 spin_lock(&wdt_lock); 53 *IXP4XX_OSWK = IXP4XX_WDT_KEY; 54 *IXP4XX_OSWE = 0; 55 *IXP4XX_OSWK = 0; 56 spin_unlock(&wdt_lock); 57 } 58 59 static int ixp4xx_wdt_open(struct inode *inode, struct file *file) 60 { 61 if (test_and_set_bit(WDT_IN_USE, &wdt_status)) 62 return -EBUSY; 63 64 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 65 wdt_enable(); 66 return nonseekable_open(inode, file); 67 } 68 69 static ssize_t 70 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) 71 { 72 if (len) { 73 if (!nowayout) { 74 size_t i; 75 76 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 77 78 for (i = 0; i != len; i++) { 79 char c; 80 81 if (get_user(c, data + i)) 82 return -EFAULT; 83 if (c == 'V') 84 set_bit(WDT_OK_TO_CLOSE, &wdt_status); 85 } 86 } 87 wdt_enable(); 88 } 89 return len; 90 } 91 92 static const struct watchdog_info ident = { 93 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | 94 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 95 .identity = "IXP4xx Watchdog", 96 }; 97 98 99 static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd, 100 unsigned long arg) 101 { 102 int ret = -ENOTTY; 103 int time; 104 105 switch (cmd) { 106 case WDIOC_GETSUPPORT: 107 ret = copy_to_user((struct watchdog_info *)arg, &ident, 108 sizeof(ident)) ? -EFAULT : 0; 109 break; 110 111 case WDIOC_GETSTATUS: 112 ret = put_user(0, (int *)arg); 113 break; 114 115 case WDIOC_GETBOOTSTATUS: 116 ret = put_user(boot_status, (int *)arg); 117 break; 118 119 case WDIOC_KEEPALIVE: 120 wdt_enable(); 121 ret = 0; 122 break; 123 124 case WDIOC_SETTIMEOUT: 125 ret = get_user(time, (int *)arg); 126 if (ret) 127 break; 128 129 if (time <= 0 || time > 60) { 130 ret = -EINVAL; 131 break; 132 } 133 134 heartbeat = time; 135 wdt_enable(); 136 /* Fall through */ 137 138 case WDIOC_GETTIMEOUT: 139 ret = put_user(heartbeat, (int *)arg); 140 break; 141 } 142 return ret; 143 } 144 145 static int ixp4xx_wdt_release(struct inode *inode, struct file *file) 146 { 147 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) 148 wdt_disable(); 149 else 150 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " 151 "timer will not stop\n"); 152 clear_bit(WDT_IN_USE, &wdt_status); 153 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 154 155 return 0; 156 } 157 158 159 static const struct file_operations ixp4xx_wdt_fops = { 160 .owner = THIS_MODULE, 161 .llseek = no_llseek, 162 .write = ixp4xx_wdt_write, 163 .unlocked_ioctl = ixp4xx_wdt_ioctl, 164 .open = ixp4xx_wdt_open, 165 .release = ixp4xx_wdt_release, 166 }; 167 168 static struct miscdevice ixp4xx_wdt_miscdev = { 169 .minor = WATCHDOG_MINOR, 170 .name = "watchdog", 171 .fops = &ixp4xx_wdt_fops, 172 }; 173 174 static int __init ixp4xx_wdt_init(void) 175 { 176 int ret; 177 178 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) { 179 printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected" 180 " - watchdog disabled\n"); 181 182 return -ENODEV; 183 } 184 spin_lock_init(&wdt_lock); 185 boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ? 186 WDIOF_CARDRESET : 0; 187 ret = misc_register(&ixp4xx_wdt_miscdev); 188 if (ret == 0) 189 printk(KERN_INFO "IXP4xx Watchdog Timer: heartbeat %d sec\n", 190 heartbeat); 191 return ret; 192 } 193 194 static void __exit ixp4xx_wdt_exit(void) 195 { 196 misc_deregister(&ixp4xx_wdt_miscdev); 197 } 198 199 200 module_init(ixp4xx_wdt_init); 201 module_exit(ixp4xx_wdt_exit); 202 203 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); 204 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog"); 205 206 module_param(heartbeat, int, 0); 207 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)"); 208 209 module_param(nowayout, int, 0); 210 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); 211 212 MODULE_LICENSE("GPL"); 213 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 214 215