- 根目录:
- drivers
- watchdog
- wdrtas.c
/*
* FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as
* RTAS calls are available
*/
/*
* RTAS watchdog driver
*
* (C) Copyright IBM Corp. 2005
* device driver to exploit watchdog RTAS functions
*
* Authors : Utz Bacher <utz.bacher@de.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <asm/rtas.h>
#define WDRTAS_MAGIC_CHAR 42
#define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \
WDIOF_MAGICCLOSE)
MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>");
MODULE_DESCRIPTION("RTAS watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS_MISCDEV(TEMP_MINOR);
static int wdrtas_nowayout = WATCHDOG_NOWAYOUT;
static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0);
static char wdrtas_expect_close;
static int wdrtas_interval;
#define WDRTAS_THERMAL_SENSOR 3
static int wdrtas_token_get_sensor_state;
#define WDRTAS_SURVEILLANCE_IND 9000
static int wdrtas_token_set_indicator;
#define WDRTAS_SP_SPI 28
static int wdrtas_token_get_sp;
static int wdrtas_token_event_scan;
#define WDRTAS_DEFAULT_INTERVAL 300
#define WDRTAS_LOGBUFFER_LEN 128
static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN];
/*** watchdog access functions */
/**
* wdrtas_set_interval - sets the watchdog interval
* @interval: new interval
*
* returns 0 on success, <0 on failures
*
* wdrtas_set_interval sets the watchdog keepalive interval by calling the
* RTAS function set-indicator (surveillance). The unit of interval is
* seconds.
*/
static int wdrtas_set_interval(int interval)
{
long result;
static int print_msg = 10;
/* rtas uses minutes */
interval = (interval + 59) / 60;
result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL,
WDRTAS_SURVEILLANCE_IND, 0, interval);
if (result < 0 && print_msg) {
printk(KERN_ERR "wdrtas: setting the watchdog to %i "
"timeout failed: %li\n", interval, result);
print_msg--;
}
return result;
}
#define WDRTAS_SP_SPI_LEN 4
/**
* wdrtas_get_interval - returns the current watchdog interval
* @fallback_value: value (in seconds) to use, if the RTAS call fails
*
* returns the interval
*
* wdrtas_get_interval returns the current watchdog keepalive interval
* as reported by the RTAS function ibm,get-system-parameter. The unit
* of the return value is seconds.
*/
static int wdrtas_get_interval(int fallback_value)
{
long result;
char value[WDRTAS_SP_SPI_LEN];
spin_lock(&rtas_data_buf_lock);
memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN);
result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
WDRTAS_SP_SPI, __pa(rtas_data_buf),
WDRTAS_SP_SPI_LEN);
memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN);
spin_unlock(&rtas_data_buf_lock);
if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) {
printk(KERN_WARNING "wdrtas: could not get sp_spi watchdog "
"timeout (%li). Continuing\n", result);
return fallback_value;
}
/* rtas uses minutes */
return ((int)value[2]) * 60;
}
/**
* wdrtas_timer_start - starts watchdog
*
* wdrtas_timer_start starts the watchdog by calling the RTAS function
* set-interval (surveillance)
*/
static void wdrtas_timer_start(void)
{
wdrtas_set_interval(wdrtas_interval);
}
/**
* wdrtas_timer_stop - stops watchdog
*
* wdrtas_timer_stop stops the watchdog timer by calling the RTAS function
* set-interval (surveillance)
*/
static void wdrtas_timer_stop(void)
{
wdrtas_set_interval(0);
}
/**
* wdrtas_log_scanned_event - logs an event we received during keepalive
*
* wdrtas_log_scanned_event prints a message to the log buffer dumping
* the results of the last event-scan call
*/
static void wdrtas_log_scanned_event(void)
{
int i;
for (i = 0; i < WDRTAS_LOGBUFFER_LEN; i += 16)
printk(KERN_INFO "wdrtas: dumping event (line %i/%i), data = "
"%02x %02x %02x %02x %02x %02x %02x %02x "
"%02x %02x %02x %02x %02x %02x %02x %02x\n",
(i / 16) + 1, (WDRTAS_LOGBUFFER_LEN / 16),
wdrtas_logbuffer[i + 0], wdrtas_logbuffer[i + 1],
wdrtas_logbuffer[i + 2], wdrtas_logbuffer[i + 3],
wdrtas_logbuffer[i + 4], wdrtas_logbuffer[i + 5],
wdrtas_logbuffer[i + 6], wdrtas_logbuffer[i + 7],
wdrtas_logbuffer[i + 8], wdrtas_logbuffer[i + 9],
wdrtas_logbuffer[i + 10], wdrtas_logbuffer[i + 11],
wdrtas_logbuffer[i + 12], wdrtas_logbuffer[i + 13],
wdrtas_logbuffer[i + 14], wdrtas_logbuffer[i + 15]);
}
/**
* wdrtas_timer_keepalive - resets watchdog timer to keep system alive
*
* wdrtas_timer_keepalive restarts the watchdog timer by calling the
* RTAS function event-scan and repeats these calls as long as there are
* events available. All events will be dumped.
*/
static void wdrtas_timer_keepalive(void)
{
long result;
do {
result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL,
RTAS_EVENT_SCAN_ALL_EVENTS, 0,
(void *)__pa(wdrtas_logbuffer),
WDRTAS_LOGBUFFER_LEN);
if (result < 0)
printk(KERN_ERR "wdrtas: event-scan failed: %li\n",
result);
if (result == 0)
wdrtas_log_scanned_event();
} while (result == 0);
}
/**
* wdrtas_get_temperature - returns current temperature
*
* returns temperature or <0 on failures
*
* wdrtas_get_temperature returns the current temperature in Fahrenheit. It
* uses the RTAS call get-sensor-state, token 3 to do so
*/
static int wdrtas_get_temperature(void)
{
int result;
int temperature = 0;
result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature);
if (result < 0)
printk(KERN_WARNING "wdrtas: reading the thermal sensor "
"failed: %i\n", result);
else
temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */
return temperature;
}
/**
* wdrtas_get_status - returns the status of the watchdog
*
* returns a bitmask of defines WDIOF_... as defined in
* include/linux/watchdog.h
*/
static int wdrtas_get_status(void)
{
return 0; /* TODO */
}
/**
* wdrtas_get_boot_status - returns the reason for the last boot
*
* returns a bitmask of defines WDIOF_... as defined in
* include/linux/watchdog.h, indicating why the watchdog rebooted the system
*/
static int wdrtas_get_boot_status(void)
{
return 0; /* TODO */
}
/*** watchdog API and operations stuff */
/* wdrtas_write - called when watchdog device is written to
* @file: file structure
* @buf: user buffer with data
* @len: amount to data written
* @ppos: position in file
*
* returns the number of successfully processed characters, which is always
* the number of bytes passed to this function
*
* wdrtas_write processes all the data given to it and looks for the magic
* character 'V'. This character allows the watchdog device to be closed
* properly.
*/
static ssize_t wdrtas_write(struct file *file, const char __user *buf,
size_t len, loff_t *ppos)
{
int i;
char c;
if (!len)
goto out;
if (!wdrtas_nowayout) {
wdrtas_expect_close = 0;
/* look for 'V' */
for (i = 0; i < len; i++) {
if (get_user(c, buf + i))
return -EFAULT;
/* allow to close device */
if (c == 'V')
wdrtas_expect_close = WDRTAS_MAGIC_CHAR;
}
}
wdrtas_timer_keepalive();
out:
return len;
}
/**
* wdrtas_ioctl - ioctl function for the watchdog device
* @file: file structure
* @cmd: command for ioctl
* @arg: argument pointer
*
* returns 0 on success, <0 on failure
*
* wdrtas_ioctl implements the watchdog API ioctls
*/
static long wdrtas_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int __user *argp = (void __user *)arg;
int i;
static const struct watchdog_info wdinfo = {
.options = WDRTAS_SUPPORTED_MASK,
.firmware_version = 0,
.identity = "wdrtas",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &wdinfo, sizeof(wdinfo)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
i = wdrtas_get_status();
return put_user(i, argp);
case WDIOC_GETBOOTSTATUS:
i = wdrtas_get_boot_status();
return put_user(i, argp);
case WDIOC_GETTEMP:
if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE)
return -EOPNOTSUPP;
i = wdrtas_get_temperature();
return put_user(i, argp);
case WDIOC_SETOPTIONS:
if (get_user(i, argp))
return -EFAULT;
if (i & WDIOS_DISABLECARD)
wdrtas_timer_stop();
if (i & WDIOS_ENABLECARD) {
wdrtas_timer_keepalive();
wdrtas_timer_start();
}
/* not implemented. Done by H8
if (i & WDIOS_TEMPPANIC) {
} */
return 0;
case WDIOC_KEEPALIVE:
wdrtas_timer_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(i, argp))
return -EFAULT;
if (wdrtas_set_interval(i))
return -EINVAL;
wdrtas_timer_keepalive();
if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
wdrtas_interval = i;
else
wdrtas_interval = wdrtas_get_interval(i);
/* fallthrough */
case WDIOC_GETTIMEOUT:
return put_user(wdrtas_interval, argp);
default:
return -ENOTTY;
}
}
/**
* wdrtas_open - open function of watchdog device
* @inode: inode structure
* @file: file structure
*
* returns 0 on success, -EBUSY if the file has been opened already, <0 on
* other failures
*
* function called when watchdog device is opened
*/
static int wdrtas_open(struct inode *inode, struct file *file)
{
/* only open once */
if (atomic_inc_return(&wdrtas_miscdev_open) > 1) {
atomic_dec(&wdrtas_miscdev_open);
return -EBUSY;
}
wdrtas_timer_start();
wdrtas_timer_keepalive();
return nonseekable_open(inode, file);
}
/**
* wdrtas_close - close function of watchdog device
* @inode: inode structure
* @file: file structure
*
* returns 0 on success
*
* close function. Always succeeds
*/
static int wdrtas_close(struct inode *inode, struct file *file)
{
/* only stop watchdog, if this was announced using 'V' before */
if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR)
wdrtas_timer_stop();
else {
printk(KERN_WARNING "wdrtas: got unexpected close. Watchdog "
"not stopped.\n");
wdrtas_timer_keepalive();
}
wdrtas_expect_close = 0;
atomic_dec(&wdrtas_miscdev_open);
return 0;
}
/**
* wdrtas_temp_read - gives back the temperature in fahrenheit
* @file: file structure
* @buf: user buffer
* @count: number of bytes to be read
* @ppos: position in file
*
* returns always 1 or -EFAULT in case of user space copy failures, <0 on
* other failures
*
* wdrtas_temp_read gives the temperature to the users by copying this
* value as one byte into the user space buffer. The unit is Fahrenheit...
*/
static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
int temperature = 0;
temperature = wdrtas_get_temperature();
if (temperature < 0)
return temperature;
if (copy_to_user(buf, &temperature, 1))
return -EFAULT;
return 1;
}
/**
* wdrtas_temp_open - open function of temperature device
* @inode: inode structure
* @file: file structure
*
* returns 0 on success, <0 on failure
*
* function called when temperature device is opened
*/
static int wdrtas_temp_open(struct inode *inode, struct file *file)
{
return nonseekable_open(inode, file);
}
/**
* wdrtas_temp_close - close function of temperature device
* @inode: inode structure
* @file: file structure
*
* returns 0 on success
*
* close function. Always succeeds
*/
static int wdrtas_temp_close(struct inode *inode, struct file *file)
{
return 0;
}
/**
* wdrtas_reboot - reboot notifier function
* @nb: notifier block structure
* @code: reboot code
* @ptr: unused
*
* returns NOTIFY_DONE
*
* wdrtas_reboot stops the watchdog in case of a reboot
*/
static int wdrtas_reboot(struct notifier_block *this,
unsigned long code, void *ptr)
{
if (code == SYS_DOWN || code == SYS_HALT)
wdrtas_timer_stop();
return NOTIFY_DONE;
}
/*** initialization stuff */
static const struct file_operations wdrtas_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = wdrtas_write,
.unlocked_ioctl = wdrtas_ioctl,
.open = wdrtas_open,
.release = wdrtas_close,
};
static struct miscdevice wdrtas_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wdrtas_fops,
};
static const struct file_operations wdrtas_temp_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = wdrtas_temp_read,
.open = wdrtas_temp_open,
.release = wdrtas_temp_close,
};
static struct miscdevice wdrtas_tempdev = {
.minor = TEMP_MINOR,
.name = "temperature",
.fops = &wdrtas_temp_fops,
};
static struct notifier_block wdrtas_notifier = {
.notifier_call = wdrtas_reboot,
};
/**
* wdrtas_get_tokens - reads in RTAS tokens
*
* returns 0 on success, <0 on failure
*
* wdrtas_get_tokens reads in the tokens for the RTAS calls used in
* this watchdog driver. It tolerates, if "get-sensor-state" and
* "ibm,get-system-parameter" are not available.
*/
static int wdrtas_get_tokens(void)
{
wdrtas_token_get_sensor_state = rtas_token("get-sensor-state");
if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) {
printk(KERN_WARNING "wdrtas: couldn't get token for "
"get-sensor-state. Trying to continue without "
"temperature support.\n");
}
wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter");
if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) {
printk(KERN_WARNING "wdrtas: couldn't get token for "
"ibm,get-system-parameter. Trying to continue with "
"a default timeout value of %i seconds.\n",
WDRTAS_DEFAULT_INTERVAL);
}
wdrtas_token_set_indicator = rtas_token("set-indicator");
if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) {
printk(KERN_ERR "wdrtas: couldn't get token for "
"set-indicator. Terminating watchdog code.\n");
return -EIO;
}
wdrtas_token_event_scan = rtas_token("event-scan");
if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) {
printk(KERN_ERR "wdrtas: couldn't get token for event-scan. "
"Terminating watchdog code.\n");
return -EIO;
}
return 0;
}
/**
* wdrtas_unregister_devs - unregisters the misc dev handlers
*
* wdrtas_register_devs unregisters the watchdog and temperature watchdog
* misc devs
*/
static void wdrtas_unregister_devs(void)
{
misc_deregister(&wdrtas_miscdev);
if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE)
misc_deregister(&wdrtas_tempdev);
}
/**
* wdrtas_register_devs - registers the misc dev handlers
*
* returns 0 on success, <0 on failure
*
* wdrtas_register_devs registers the watchdog and temperature watchdog
* misc devs
*/
static int wdrtas_register_devs(void)
{
int result;
result = misc_register(&wdrtas_miscdev);
if (result) {
printk(KERN_ERR "wdrtas: couldn't register watchdog misc "
"device. Terminating watchdog code.\n");
return result;
}
if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) {
result = misc_register(&wdrtas_tempdev);
if (result) {
printk(KERN_WARNING "wdrtas: couldn't register "
"watchdog temperature misc device. Continuing "
"without temperature support.\n");
wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE;
}
}
return 0;
}
/**
* wdrtas_init - init function of the watchdog driver
*
* returns 0 on success, <0 on failure
*
* registers the file handlers and the reboot notifier
*/
static int __init wdrtas_init(void)
{
if (wdrtas_get_tokens())
return -ENODEV;
if (wdrtas_register_devs())
return -ENODEV;
if (register_reboot_notifier(&wdrtas_notifier)) {
printk(KERN_ERR "wdrtas: could not register reboot notifier. "
"Terminating watchdog code.\n");
wdrtas_unregister_devs();
return -ENODEV;
}
if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE)
wdrtas_interval = WDRTAS_DEFAULT_INTERVAL;
else
wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL);
return 0;
}
/**
* wdrtas_exit - exit function of the watchdog driver
*
* unregisters the file handlers and the reboot notifier
*/
static void __exit wdrtas_exit(void)
{
if (!wdrtas_nowayout)
wdrtas_timer_stop();
wdrtas_unregister_devs();
unregister_reboot_notifier(&wdrtas_notifier);
}
module_init(wdrtas_init);
module_exit(wdrtas_exit);