linux/drivers/watchdog/wdrtas.c
Thomas Gleixner de6cc6515a treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 153
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 77 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.837555891@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

628 lines
15 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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");
static bool 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) {
pr_err("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) {
pr_warn("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_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)
pr_err("event-scan failed: %li\n", result);
if (result == 0)
print_hex_dump(KERN_INFO, "dumping event, data: ",
DUMP_PREFIX_OFFSET, 16, 1,
wdrtas_logbuffer, WDRTAS_LOGBUFFER_LEN, false);
} 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)
pr_warn("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 stream_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 {
pr_warn("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 stream_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) {
pr_warn("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) {
pr_warn("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) {
pr_err("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) {
pr_err("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) {
pr_err("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) {
pr_warn("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)) {
pr_err("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);