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