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 26 #include <asm/hardware.h> 27 #include <asm/uaccess.h> 28 29 static int nowayout = WATCHDOG_NOWAYOUT; 30 static int heartbeat = 60; /* (secs) Default is 1 minute */ 31 static unsigned long wdt_status; 32 static unsigned long boot_status; 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 40 wdt_enable(void) 41 { 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 } 48 49 static void 50 wdt_disable(void) 51 { 52 *IXP4XX_OSWK = IXP4XX_WDT_KEY; 53 *IXP4XX_OSWE = 0; 54 *IXP4XX_OSWK = 0; 55 } 56 57 static int 58 ixp4xx_wdt_open(struct inode *inode, struct file *file) 59 { 60 if (test_and_set_bit(WDT_IN_USE, &wdt_status)) 61 return -EBUSY; 62 63 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 64 65 wdt_enable(); 66 67 return nonseekable_open(inode, file); 68 } 69 70 static ssize_t 71 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) 72 { 73 if (len) { 74 if (!nowayout) { 75 size_t i; 76 77 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 78 79 for (i = 0; i != len; i++) { 80 char c; 81 82 if (get_user(c, data + i)) 83 return -EFAULT; 84 if (c == 'V') 85 set_bit(WDT_OK_TO_CLOSE, &wdt_status); 86 } 87 } 88 wdt_enable(); 89 } 90 91 return len; 92 } 93 94 static struct watchdog_info ident = { 95 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | 96 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 97 .identity = "IXP4xx Watchdog", 98 }; 99 100 101 static int 102 ixp4xx_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, 103 unsigned long arg) 104 { 105 int ret = -ENOTTY; 106 int time; 107 108 switch (cmd) { 109 case WDIOC_GETSUPPORT: 110 ret = copy_to_user((struct watchdog_info *)arg, &ident, 111 sizeof(ident)) ? -EFAULT : 0; 112 break; 113 114 case WDIOC_GETSTATUS: 115 ret = put_user(0, (int *)arg); 116 break; 117 118 case WDIOC_GETBOOTSTATUS: 119 ret = put_user(boot_status, (int *)arg); 120 break; 121 122 case WDIOC_SETTIMEOUT: 123 ret = get_user(time, (int *)arg); 124 if (ret) 125 break; 126 127 if (time <= 0 || time > 60) { 128 ret = -EINVAL; 129 break; 130 } 131 132 heartbeat = time; 133 wdt_enable(); 134 /* Fall through */ 135 136 case WDIOC_GETTIMEOUT: 137 ret = put_user(heartbeat, (int *)arg); 138 break; 139 140 case WDIOC_KEEPALIVE: 141 wdt_enable(); 142 ret = 0; 143 break; 144 } 145 return ret; 146 } 147 148 static int 149 ixp4xx_wdt_release(struct inode *inode, struct file *file) 150 { 151 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { 152 wdt_disable(); 153 } else { 154 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " 155 "timer will not stop\n"); 156 } 157 158 clear_bit(WDT_IN_USE, &wdt_status); 159 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 160 161 return 0; 162 } 163 164 165 static const struct file_operations ixp4xx_wdt_fops = 166 { 167 .owner = THIS_MODULE, 168 .llseek = no_llseek, 169 .write = ixp4xx_wdt_write, 170 .ioctl = ixp4xx_wdt_ioctl, 171 .open = ixp4xx_wdt_open, 172 .release = ixp4xx_wdt_release, 173 }; 174 175 static struct miscdevice ixp4xx_wdt_miscdev = 176 { 177 .minor = WATCHDOG_MINOR, 178 .name = "watchdog", 179 .fops = &ixp4xx_wdt_fops, 180 }; 181 182 static int __init ixp4xx_wdt_init(void) 183 { 184 int ret; 185 unsigned long processor_id; 186 187 asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :); 188 if (!(processor_id & 0xf) && !cpu_is_ixp46x()) { 189 printk("IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected - " 190 "watchdog disabled\n"); 191 192 return -ENODEV; 193 } 194 195 ret = misc_register(&ixp4xx_wdt_miscdev); 196 if (ret == 0) 197 printk("IXP4xx Watchdog Timer: heartbeat %d sec\n", heartbeat); 198 199 boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ? 200 WDIOF_CARDRESET : 0; 201 202 return ret; 203 } 204 205 static void __exit ixp4xx_wdt_exit(void) 206 { 207 misc_deregister(&ixp4xx_wdt_miscdev); 208 } 209 210 211 module_init(ixp4xx_wdt_init); 212 module_exit(ixp4xx_wdt_exit); 213 214 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); 215 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog"); 216 217 module_param(heartbeat, int, 0); 218 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)"); 219 220 module_param(nowayout, int, 0); 221 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); 222 223 MODULE_LICENSE("GPL"); 224 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 225 226