Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 1 | /* |
| 2 | * NANO7240 SBC Watchdog device driver |
| 3 | * |
| 4 | * Based on w83877f.c by Scott Jennings, |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation; |
| 9 | * |
| 10 | * Software distributed under the License is distributed on an "AS IS" |
| 11 | * basis, WITHOUT WARRANTY OF ANY KIND, either express or |
| 12 | * implied. See the License for the specific language governing |
| 13 | * rights and limitations under the License. |
| 14 | * |
| 15 | * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au> |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | #include <linux/fs.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/ioport.h> |
| 22 | #include <linux/jiffies.h> |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/moduleparam.h> |
| 25 | #include <linux/miscdevice.h> |
| 26 | #include <linux/notifier.h> |
| 27 | #include <linux/reboot.h> |
| 28 | #include <linux/types.h> |
| 29 | #include <linux/watchdog.h> |
Alan Cox | 619a8a2 | 2008-05-19 14:08:16 +0100 | [diff] [blame] | 30 | #include <linux/io.h> |
| 31 | #include <linux/uaccess.h> |
Arun Sharma | 6006349 | 2011-07-26 16:09:06 -0700 | [diff] [blame] | 32 | #include <linux/atomic.h> |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 33 | #include <asm/system.h> |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 34 | |
| 35 | #define SBC7240_PREFIX "sbc7240_wdt: " |
| 36 | |
| 37 | #define SBC7240_ENABLE_PORT 0x443 |
| 38 | #define SBC7240_DISABLE_PORT 0x043 |
| 39 | #define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT |
| 40 | #define SBC7240_MAGIC_CHAR 'V' |
| 41 | |
| 42 | #define SBC7240_TIMEOUT 30 |
| 43 | #define SBC7240_MAX_TIMEOUT 255 |
| 44 | static int timeout = SBC7240_TIMEOUT; /* in seconds */ |
| 45 | module_param(timeout, int, 0); |
| 46 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=" |
| 47 | __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default=" |
| 48 | __MODULE_STRING(SBC7240_TIMEOUT) ")"); |
| 49 | |
| 50 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 51 | module_param(nowayout, int, 0); |
| 52 | MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file"); |
| 53 | |
| 54 | #define SBC7240_OPEN_STATUS_BIT 0 |
| 55 | #define SBC7240_ENABLED_STATUS_BIT 1 |
| 56 | #define SBC7240_EXPECT_CLOSE_STATUS_BIT 2 |
| 57 | static unsigned long wdt_status; |
| 58 | |
| 59 | /* |
| 60 | * Utility routines |
| 61 | */ |
| 62 | |
| 63 | static void wdt_disable(void) |
| 64 | { |
| 65 | /* disable the watchdog */ |
| 66 | if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { |
| 67 | inb_p(SBC7240_DISABLE_PORT); |
| 68 | printk(KERN_INFO SBC7240_PREFIX |
| 69 | "Watchdog timer is now disabled.\n"); |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | static void wdt_enable(void) |
| 74 | { |
| 75 | /* enable the watchdog */ |
| 76 | if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { |
| 77 | inb_p(SBC7240_ENABLE_PORT); |
| 78 | printk(KERN_INFO SBC7240_PREFIX |
| 79 | "Watchdog timer is now enabled.\n"); |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | static int wdt_set_timeout(int t) |
| 84 | { |
| 85 | if (t < 1 || t > SBC7240_MAX_TIMEOUT) { |
| 86 | printk(KERN_ERR SBC7240_PREFIX |
| 87 | "timeout value must be 1<=x<=%d\n", |
| 88 | SBC7240_MAX_TIMEOUT); |
| 89 | return -1; |
| 90 | } |
| 91 | /* set the timeout */ |
| 92 | outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT); |
| 93 | timeout = t; |
| 94 | printk(KERN_INFO SBC7240_PREFIX "timeout set to %d seconds\n", t); |
| 95 | return 0; |
| 96 | } |
| 97 | |
| 98 | /* Whack the dog */ |
| 99 | static inline void wdt_keepalive(void) |
| 100 | { |
| 101 | if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) |
| 102 | inb_p(SBC7240_ENABLE_PORT); |
| 103 | } |
| 104 | |
| 105 | /* |
| 106 | * /dev/watchdog handling |
| 107 | */ |
| 108 | static ssize_t fop_write(struct file *file, const char __user *buf, |
| 109 | size_t count, loff_t *ppos) |
| 110 | { |
| 111 | size_t i; |
| 112 | char c; |
| 113 | |
| 114 | if (count) { |
| 115 | if (!nowayout) { |
| 116 | clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, |
| 117 | &wdt_status); |
| 118 | |
| 119 | /* is there a magic char ? */ |
| 120 | for (i = 0; i != count; i++) { |
| 121 | if (get_user(c, buf + i)) |
| 122 | return -EFAULT; |
| 123 | if (c == SBC7240_MAGIC_CHAR) { |
| 124 | set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, |
| 125 | &wdt_status); |
| 126 | break; |
| 127 | } |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | wdt_keepalive(); |
| 132 | } |
| 133 | |
| 134 | return count; |
| 135 | } |
| 136 | |
| 137 | static int fop_open(struct inode *inode, struct file *file) |
| 138 | { |
| 139 | if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status)) |
| 140 | return -EBUSY; |
| 141 | |
| 142 | wdt_enable(); |
| 143 | |
| 144 | return nonseekable_open(inode, file); |
| 145 | } |
| 146 | |
| 147 | static int fop_close(struct inode *inode, struct file *file) |
| 148 | { |
| 149 | if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status) |
| 150 | || !nowayout) { |
| 151 | wdt_disable(); |
| 152 | } else { |
| 153 | printk(KERN_CRIT SBC7240_PREFIX |
| 154 | "Unexpected close, not stopping watchdog!\n"); |
| 155 | wdt_keepalive(); |
| 156 | } |
| 157 | |
| 158 | clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status); |
| 159 | return 0; |
| 160 | } |
| 161 | |
Alan Cox | 619a8a2 | 2008-05-19 14:08:16 +0100 | [diff] [blame] | 162 | static const struct watchdog_info ident = { |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 163 | .options = WDIOF_KEEPALIVEPING| |
| 164 | WDIOF_SETTIMEOUT| |
| 165 | WDIOF_MAGICCLOSE, |
| 166 | .firmware_version = 1, |
| 167 | .identity = "SBC7240", |
| 168 | }; |
| 169 | |
| 170 | |
Alan Cox | 619a8a2 | 2008-05-19 14:08:16 +0100 | [diff] [blame] | 171 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 172 | { |
| 173 | switch (cmd) { |
| 174 | case WDIOC_GETSUPPORT: |
Alan Cox | 619a8a2 | 2008-05-19 14:08:16 +0100 | [diff] [blame] | 175 | return copy_to_user((void __user *)arg, &ident, sizeof(ident)) |
| 176 | ? -EFAULT : 0; |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 177 | case WDIOC_GETSTATUS: |
| 178 | case WDIOC_GETBOOTSTATUS: |
| 179 | return put_user(0, (int __user *)arg); |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 180 | case WDIOC_SETOPTIONS: |
| 181 | { |
| 182 | int options; |
| 183 | int retval = -EINVAL; |
| 184 | |
| 185 | if (get_user(options, (int __user *)arg)) |
| 186 | return -EFAULT; |
| 187 | |
| 188 | if (options & WDIOS_DISABLECARD) { |
| 189 | wdt_disable(); |
| 190 | retval = 0; |
| 191 | } |
| 192 | |
| 193 | if (options & WDIOS_ENABLECARD) { |
| 194 | wdt_enable(); |
| 195 | retval = 0; |
| 196 | } |
| 197 | |
| 198 | return retval; |
| 199 | } |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 200 | case WDIOC_KEEPALIVE: |
| 201 | wdt_keepalive(); |
| 202 | return 0; |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 203 | case WDIOC_SETTIMEOUT: |
| 204 | { |
| 205 | int new_timeout; |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 206 | |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 207 | if (get_user(new_timeout, (int __user *)arg)) |
| 208 | return -EFAULT; |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 209 | |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 210 | if (wdt_set_timeout(new_timeout)) |
| 211 | return -EINVAL; |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 212 | |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 213 | /* Fall through */ |
| 214 | } |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 215 | case WDIOC_GETTIMEOUT: |
| 216 | return put_user(timeout, (int __user *)arg); |
| 217 | default: |
| 218 | return -ENOTTY; |
| 219 | } |
| 220 | } |
| 221 | |
| 222 | static const struct file_operations wdt_fops = { |
| 223 | .owner = THIS_MODULE, |
| 224 | .llseek = no_llseek, |
| 225 | .write = fop_write, |
| 226 | .open = fop_open, |
| 227 | .release = fop_close, |
Alan Cox | 619a8a2 | 2008-05-19 14:08:16 +0100 | [diff] [blame] | 228 | .unlocked_ioctl = fop_ioctl, |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 229 | }; |
| 230 | |
| 231 | static struct miscdevice wdt_miscdev = { |
| 232 | .minor = WATCHDOG_MINOR, |
| 233 | .name = "watchdog", |
| 234 | .fops = &wdt_fops, |
| 235 | }; |
| 236 | |
| 237 | /* |
| 238 | * Notifier for system down |
| 239 | */ |
| 240 | |
| 241 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, |
| 242 | void *unused) |
| 243 | { |
| 244 | if (code == SYS_DOWN || code == SYS_HALT) |
| 245 | wdt_disable(); |
| 246 | return NOTIFY_DONE; |
| 247 | } |
| 248 | |
| 249 | static struct notifier_block wdt_notifier = { |
| 250 | .notifier_call = wdt_notify_sys, |
| 251 | }; |
| 252 | |
| 253 | static void __exit sbc7240_wdt_unload(void) |
| 254 | { |
| 255 | printk(KERN_INFO SBC7240_PREFIX "Removing watchdog\n"); |
| 256 | misc_deregister(&wdt_miscdev); |
| 257 | |
| 258 | unregister_reboot_notifier(&wdt_notifier); |
| 259 | release_region(SBC7240_ENABLE_PORT, 1); |
| 260 | } |
| 261 | |
| 262 | static int __init sbc7240_wdt_init(void) |
| 263 | { |
| 264 | int rc = -EBUSY; |
| 265 | |
| 266 | if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) { |
| 267 | printk(KERN_ERR SBC7240_PREFIX |
| 268 | "I/O address 0x%04x already in use\n", |
| 269 | SBC7240_ENABLE_PORT); |
| 270 | rc = -EIO; |
| 271 | goto err_out; |
| 272 | } |
| 273 | |
| 274 | /* The IO port 0x043 used to disable the watchdog |
| 275 | * is already claimed by the system timer, so we |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 276 | * can't request_region() it ...*/ |
Gilles Gigan | c4c2833 | 2007-10-31 16:31:42 +1000 | [diff] [blame] | 277 | |
| 278 | if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) { |
| 279 | timeout = SBC7240_TIMEOUT; |
| 280 | printk(KERN_INFO SBC7240_PREFIX |
| 281 | "timeout value must be 1<=x<=%d, using %d\n", |
| 282 | SBC7240_MAX_TIMEOUT, timeout); |
| 283 | } |
| 284 | wdt_set_timeout(timeout); |
| 285 | wdt_disable(); |
| 286 | |
| 287 | rc = register_reboot_notifier(&wdt_notifier); |
| 288 | if (rc) { |
| 289 | printk(KERN_ERR SBC7240_PREFIX |
| 290 | "cannot register reboot notifier (err=%d)\n", rc); |
| 291 | goto err_out_region; |
| 292 | } |
| 293 | |
| 294 | rc = misc_register(&wdt_miscdev); |
| 295 | if (rc) { |
| 296 | printk(KERN_ERR SBC7240_PREFIX |
| 297 | "cannot register miscdev on minor=%d (err=%d)\n", |
| 298 | wdt_miscdev.minor, rc); |
| 299 | goto err_out_reboot_notifier; |
| 300 | } |
| 301 | |
| 302 | printk(KERN_INFO SBC7240_PREFIX |
| 303 | "Watchdog driver for SBC7240 initialised (nowayout=%d)\n", |
| 304 | nowayout); |
| 305 | |
| 306 | return 0; |
| 307 | |
| 308 | err_out_reboot_notifier: |
| 309 | unregister_reboot_notifier(&wdt_notifier); |
| 310 | err_out_region: |
| 311 | release_region(SBC7240_ENABLE_PORT, 1); |
| 312 | err_out: |
| 313 | return rc; |
| 314 | } |
| 315 | |
| 316 | module_init(sbc7240_wdt_init); |
| 317 | module_exit(sbc7240_wdt_unload); |
| 318 | |
| 319 | MODULE_AUTHOR("Gilles Gigan"); |
| 320 | MODULE_DESCRIPTION("Watchdog device driver for single board" |
| 321 | " computers EPIC Nano 7240 from iEi"); |
| 322 | MODULE_LICENSE("GPL"); |
| 323 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| 324 | |