Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* drivers/char/watchdog/scx200_wdt.c |
| 2 | |
| 3 | National Semiconductor SCx200 Watchdog support |
| 4 | |
| 5 | Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> |
| 6 | |
| 7 | Some code taken from: |
| 8 | National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver |
| 9 | (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com> |
| 10 | |
| 11 | This program is free software; you can redistribute it and/or |
| 12 | modify it under the terms of the GNU General Public License as |
| 13 | published by the Free Software Foundation; either version 2 of the |
| 14 | License, or (at your option) any later version. |
| 15 | |
| 16 | The author(s) of this software shall not be held liable for damages |
| 17 | of any nature resulting due to the use of this software. This |
| 18 | software is provided AS-IS with no warranties. */ |
| 19 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/module.h> |
| 21 | #include <linux/moduleparam.h> |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/miscdevice.h> |
| 24 | #include <linux/watchdog.h> |
| 25 | #include <linux/notifier.h> |
| 26 | #include <linux/reboot.h> |
| 27 | #include <linux/fs.h> |
| 28 | #include <linux/pci.h> |
| 29 | #include <linux/scx200.h> |
| 30 | |
| 31 | #include <asm/uaccess.h> |
| 32 | #include <asm/io.h> |
| 33 | |
| 34 | #define NAME "scx200_wdt" |
| 35 | |
| 36 | MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); |
| 37 | MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver"); |
| 38 | MODULE_LICENSE("GPL"); |
| 39 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| 40 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | static int margin = 60; /* in seconds */ |
| 42 | module_param(margin, int, 0); |
| 43 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); |
| 44 | |
Andrey Panin | 4bfdf37 | 2005-07-27 11:43:58 -0700 | [diff] [blame] | 45 | static int nowayout = WATCHDOG_NOWAYOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | module_param(nowayout, int, 0); |
| 47 | MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); |
| 48 | |
| 49 | static u16 wdto_restart; |
| 50 | static struct semaphore open_semaphore; |
| 51 | static char expect_close; |
| 52 | |
| 53 | /* Bits of the WDCNFG register */ |
| 54 | #define W_ENABLE 0x00fa /* Enable watchdog */ |
| 55 | #define W_DISABLE 0x0000 /* Disable watchdog */ |
| 56 | |
| 57 | /* The scaling factor for the timer, this depends on the value of W_ENABLE */ |
| 58 | #define W_SCALE (32768/1024) |
| 59 | |
| 60 | static void scx200_wdt_ping(void) |
| 61 | { |
| 62 | outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO); |
| 63 | } |
| 64 | |
| 65 | static void scx200_wdt_update_margin(void) |
| 66 | { |
| 67 | printk(KERN_INFO NAME ": timer margin %d seconds\n", margin); |
| 68 | wdto_restart = margin * W_SCALE; |
| 69 | } |
| 70 | |
| 71 | static void scx200_wdt_enable(void) |
| 72 | { |
| 73 | printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n", |
| 74 | wdto_restart); |
| 75 | |
| 76 | outw(0, scx200_cb_base + SCx200_WDT_WDTO); |
| 77 | outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); |
| 78 | outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG); |
| 79 | |
| 80 | scx200_wdt_ping(); |
| 81 | } |
| 82 | |
| 83 | static void scx200_wdt_disable(void) |
| 84 | { |
| 85 | printk(KERN_DEBUG NAME ": disabling watchdog timer\n"); |
| 86 | |
| 87 | outw(0, scx200_cb_base + SCx200_WDT_WDTO); |
| 88 | outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); |
| 89 | outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG); |
| 90 | } |
| 91 | |
| 92 | static int scx200_wdt_open(struct inode *inode, struct file *file) |
| 93 | { |
| 94 | /* only allow one at a time */ |
| 95 | if (down_trylock(&open_semaphore)) |
| 96 | return -EBUSY; |
| 97 | scx200_wdt_enable(); |
| 98 | |
| 99 | return nonseekable_open(inode, file); |
| 100 | } |
| 101 | |
| 102 | static int scx200_wdt_release(struct inode *inode, struct file *file) |
| 103 | { |
| 104 | if (expect_close != 42) { |
| 105 | printk(KERN_WARNING NAME ": watchdog device closed unexpectedly, will not disable the watchdog timer\n"); |
| 106 | } else if (!nowayout) { |
| 107 | scx200_wdt_disable(); |
| 108 | } |
| 109 | expect_close = 0; |
| 110 | up(&open_semaphore); |
| 111 | |
| 112 | return 0; |
| 113 | } |
| 114 | |
| 115 | static int scx200_wdt_notify_sys(struct notifier_block *this, |
| 116 | unsigned long code, void *unused) |
| 117 | { |
| 118 | if (code == SYS_HALT || code == SYS_POWER_OFF) |
| 119 | if (!nowayout) |
| 120 | scx200_wdt_disable(); |
| 121 | |
| 122 | return NOTIFY_DONE; |
| 123 | } |
| 124 | |
| 125 | static struct notifier_block scx200_wdt_notifier = |
| 126 | { |
| 127 | .notifier_call = scx200_wdt_notify_sys, |
| 128 | }; |
| 129 | |
| 130 | static ssize_t scx200_wdt_write(struct file *file, const char __user *data, |
| 131 | size_t len, loff_t *ppos) |
| 132 | { |
| 133 | /* check for a magic close character */ |
| 134 | if (len) |
| 135 | { |
| 136 | size_t i; |
| 137 | |
| 138 | scx200_wdt_ping(); |
| 139 | |
| 140 | expect_close = 0; |
| 141 | for (i = 0; i < len; ++i) { |
| 142 | char c; |
| 143 | if (get_user(c, data+i)) |
| 144 | return -EFAULT; |
| 145 | if (c == 'V') |
| 146 | expect_close = 42; |
| 147 | } |
| 148 | |
| 149 | return len; |
| 150 | } |
| 151 | |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | static int scx200_wdt_ioctl(struct inode *inode, struct file *file, |
| 156 | unsigned int cmd, unsigned long arg) |
| 157 | { |
| 158 | void __user *argp = (void __user *)arg; |
| 159 | int __user *p = argp; |
| 160 | static struct watchdog_info ident = { |
| 161 | .identity = "NatSemi SCx200 Watchdog", |
| 162 | .firmware_version = 1, |
| 163 | .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING), |
| 164 | }; |
| 165 | int new_margin; |
| 166 | |
| 167 | switch (cmd) { |
| 168 | default: |
| 169 | return -ENOIOCTLCMD; |
| 170 | case WDIOC_GETSUPPORT: |
| 171 | if(copy_to_user(argp, &ident, sizeof(ident))) |
| 172 | return -EFAULT; |
| 173 | return 0; |
| 174 | case WDIOC_GETSTATUS: |
| 175 | case WDIOC_GETBOOTSTATUS: |
| 176 | if (put_user(0, p)) |
| 177 | return -EFAULT; |
| 178 | return 0; |
| 179 | case WDIOC_KEEPALIVE: |
| 180 | scx200_wdt_ping(); |
| 181 | return 0; |
| 182 | case WDIOC_SETTIMEOUT: |
| 183 | if (get_user(new_margin, p)) |
| 184 | return -EFAULT; |
| 185 | if (new_margin < 1) |
| 186 | return -EINVAL; |
| 187 | margin = new_margin; |
| 188 | scx200_wdt_update_margin(); |
| 189 | scx200_wdt_ping(); |
| 190 | case WDIOC_GETTIMEOUT: |
| 191 | if (put_user(margin, p)) |
| 192 | return -EFAULT; |
| 193 | return 0; |
| 194 | } |
| 195 | } |
| 196 | |
Arjan van de Ven | 62322d2 | 2006-07-03 00:24:21 -0700 | [diff] [blame] | 197 | static const struct file_operations scx200_wdt_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | .owner = THIS_MODULE, |
| 199 | .llseek = no_llseek, |
| 200 | .write = scx200_wdt_write, |
| 201 | .ioctl = scx200_wdt_ioctl, |
| 202 | .open = scx200_wdt_open, |
| 203 | .release = scx200_wdt_release, |
| 204 | }; |
| 205 | |
| 206 | static struct miscdevice scx200_wdt_miscdev = { |
| 207 | .minor = WATCHDOG_MINOR, |
Olaf Hering | 2dab3ca | 2005-08-17 08:58:34 +0200 | [diff] [blame] | 208 | .name = "watchdog", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | .fops = &scx200_wdt_fops, |
| 210 | }; |
| 211 | |
| 212 | static int __init scx200_wdt_init(void) |
| 213 | { |
| 214 | int r; |
| 215 | |
| 216 | printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n"); |
| 217 | |
| 218 | /* check that we have found the configuration block */ |
| 219 | if (!scx200_cb_present()) |
| 220 | return -ENODEV; |
| 221 | |
| 222 | if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET, |
| 223 | SCx200_WDT_SIZE, |
| 224 | "NatSemi SCx200 Watchdog")) { |
| 225 | printk(KERN_WARNING NAME ": watchdog I/O region busy\n"); |
| 226 | return -EBUSY; |
| 227 | } |
| 228 | |
| 229 | scx200_wdt_update_margin(); |
| 230 | scx200_wdt_disable(); |
| 231 | |
| 232 | sema_init(&open_semaphore, 1); |
| 233 | |
| 234 | r = misc_register(&scx200_wdt_miscdev); |
| 235 | if (r) { |
| 236 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
| 237 | SCx200_WDT_SIZE); |
| 238 | return r; |
| 239 | } |
| 240 | |
| 241 | r = register_reboot_notifier(&scx200_wdt_notifier); |
| 242 | if (r) { |
| 243 | printk(KERN_ERR NAME ": unable to register reboot notifier"); |
| 244 | misc_deregister(&scx200_wdt_miscdev); |
| 245 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
| 246 | SCx200_WDT_SIZE); |
| 247 | return r; |
| 248 | } |
| 249 | |
| 250 | return 0; |
| 251 | } |
| 252 | |
| 253 | static void __exit scx200_wdt_cleanup(void) |
| 254 | { |
| 255 | unregister_reboot_notifier(&scx200_wdt_notifier); |
| 256 | misc_deregister(&scx200_wdt_miscdev); |
| 257 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
| 258 | SCx200_WDT_SIZE); |
| 259 | } |
| 260 | |
| 261 | module_init(scx200_wdt_init); |
| 262 | module_exit(scx200_wdt_cleanup); |
| 263 | |
| 264 | /* |
| 265 | Local variables: |
| 266 | compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules" |
| 267 | c-basic-offset: 8 |
| 268 | End: |
| 269 | */ |