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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 17 18 #include <linux/module.h> 19 #include <linux/moduleparam.h> 20 #include <linux/types.h> 21 #include <linux/kernel.h> 22 #include <linux/fs.h> 23 #include <linux/miscdevice.h> 24 #include <linux/watchdog.h> 25 #include <linux/init.h> 26 #include <linux/bitops.h> 27 #include <linux/uaccess.h> 28 #include <mach/hardware.h> 29 30 static bool nowayout = WATCHDOG_NOWAYOUT; 31 static int heartbeat = 60; /* (secs) Default is 1 minute */ 32 static unsigned long wdt_status; 33 static unsigned long boot_status; 34 static DEFINE_SPINLOCK(wdt_lock); 35 36 #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL) 37 38 #define WDT_IN_USE 0 39 #define WDT_OK_TO_CLOSE 1 40 41 static void wdt_enable(void) 42 { 43 spin_lock(&wdt_lock); 44 *IXP4XX_OSWK = IXP4XX_WDT_KEY; 45 *IXP4XX_OSWE = 0; 46 *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat; 47 *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE; 48 *IXP4XX_OSWK = 0; 49 spin_unlock(&wdt_lock); 50 } 51 52 static void wdt_disable(void) 53 { 54 spin_lock(&wdt_lock); 55 *IXP4XX_OSWK = IXP4XX_WDT_KEY; 56 *IXP4XX_OSWE = 0; 57 *IXP4XX_OSWK = 0; 58 spin_unlock(&wdt_lock); 59 } 60 61 static int ixp4xx_wdt_open(struct inode *inode, struct file *file) 62 { 63 if (test_and_set_bit(WDT_IN_USE, &wdt_status)) 64 return -EBUSY; 65 66 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 67 wdt_enable(); 68 return nonseekable_open(inode, file); 69 } 70 71 static ssize_t 72 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) 73 { 74 if (len) { 75 if (!nowayout) { 76 size_t i; 77 78 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 79 80 for (i = 0; i != len; i++) { 81 char c; 82 83 if (get_user(c, data + i)) 84 return -EFAULT; 85 if (c == 'V') 86 set_bit(WDT_OK_TO_CLOSE, &wdt_status); 87 } 88 } 89 wdt_enable(); 90 } 91 return len; 92 } 93 94 static const struct watchdog_info ident = { 95 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | 96 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 97 .identity = "IXP4xx Watchdog", 98 }; 99 100 101 static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd, 102 unsigned long arg) 103 { 104 int ret = -ENOTTY; 105 int time; 106 107 switch (cmd) { 108 case WDIOC_GETSUPPORT: 109 ret = copy_to_user((struct watchdog_info *)arg, &ident, 110 sizeof(ident)) ? -EFAULT : 0; 111 break; 112 113 case WDIOC_GETSTATUS: 114 ret = put_user(0, (int *)arg); 115 break; 116 117 case WDIOC_GETBOOTSTATUS: 118 ret = put_user(boot_status, (int *)arg); 119 break; 120 121 case WDIOC_KEEPALIVE: 122 wdt_enable(); 123 ret = 0; 124 break; 125 126 case WDIOC_SETTIMEOUT: 127 ret = get_user(time, (int *)arg); 128 if (ret) 129 break; 130 131 if (time <= 0 || time > 60) { 132 ret = -EINVAL; 133 break; 134 } 135 136 heartbeat = time; 137 wdt_enable(); 138 /* Fall through */ 139 140 case WDIOC_GETTIMEOUT: 141 ret = put_user(heartbeat, (int *)arg); 142 break; 143 } 144 return ret; 145 } 146 147 static int ixp4xx_wdt_release(struct inode *inode, struct file *file) 148 { 149 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) 150 wdt_disable(); 151 else 152 pr_crit("Device closed unexpectedly - timer will not stop\n"); 153 clear_bit(WDT_IN_USE, &wdt_status); 154 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 155 156 return 0; 157 } 158 159 160 static const struct file_operations ixp4xx_wdt_fops = { 161 .owner = THIS_MODULE, 162 .llseek = no_llseek, 163 .write = ixp4xx_wdt_write, 164 .unlocked_ioctl = ixp4xx_wdt_ioctl, 165 .open = ixp4xx_wdt_open, 166 .release = ixp4xx_wdt_release, 167 }; 168 169 static struct miscdevice ixp4xx_wdt_miscdev = { 170 .minor = WATCHDOG_MINOR, 171 .name = "watchdog", 172 .fops = &ixp4xx_wdt_fops, 173 }; 174 175 static int __init ixp4xx_wdt_init(void) 176 { 177 int ret; 178 179 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) { 180 pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n"); 181 182 return -ENODEV; 183 } 184 boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ? 185 WDIOF_CARDRESET : 0; 186 ret = misc_register(&ixp4xx_wdt_miscdev); 187 if (ret == 0) 188 pr_info("timer heartbeat %d sec\n", heartbeat); 189 return ret; 190 } 191 192 static void __exit ixp4xx_wdt_exit(void) 193 { 194 misc_deregister(&ixp4xx_wdt_miscdev); 195 } 196 197 198 module_init(ixp4xx_wdt_init); 199 module_exit(ixp4xx_wdt_exit); 200 201 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); 202 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog"); 203 204 module_param(heartbeat, int, 0); 205 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)"); 206 207 module_param(nowayout, bool, 0); 208 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); 209 210 MODULE_LICENSE("GPL"); 211