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|
/*
* 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);
#ifdef CONFIG_WATCHDOG_NOWAYOUT
static int wdrtas_nowayout = 1;
#else
static int wdrtas_nowayout = 0;
#endif
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;
}
/**
* 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[4];
result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL,
WDRTAS_SP_SPI, (void *)__pa(&value), 4);
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)
{
long result;
int temperature = 0;
result = rtas_call(wdrtas_token_get_sensor_state, 2, 2,
(void *)__pa(&temperature),
WDRTAS_THERMAL_SENSOR, 0);
if (result < 0)
printk(KERN_WARNING "wdrtas: reading the thermal sensor "
"faild: %li\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;
|