// SPDX-License-Identifier: GPL-2.0-or-later
/*
* National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
* (c) Copyright 2002 Zwane Mwaikambo <[email protected]>,
* All Rights Reserved.
* Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
*
* The author(s) of this software shall not be held liable for damages
* of any nature resulting due to the use of this software. This
* software is provided AS-IS with no warranties.
*
* Changelog:
* 20020220 Zwane Mwaikambo Code based on datasheet, no hardware.
* 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik
* and Alan Cox.
* 20020222 Zwane Mwaikambo Added probing.
* 20020225 Zwane Mwaikambo Added ISAPNP support.
* 20020412 Rob Radez Broke out start/stop functions
* <[email protected]> Return proper status instead of
* temperature warning
* Add WDIOC_GETBOOTSTATUS and
* WDIOC_SETOPTIONS ioctls
* Fix CONFIG_WATCHDOG_NOWAYOUT
* 20020530 Joel Becker Add Matt Domsch's nowayout module
* option
* 20030116 Adam Belay Updated to the latest pnp code
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/spinlock.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/pnp.h>
#include <linux/fs.h>
#include <linux/semaphore.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#define SC1200_MODULE_VER "build 20020303"
#define SC1200_MODULE_NAME "sc1200wdt"
#define MAX_TIMEOUT 255 /* 255 minutes */
#define PMIR (io) /* Power Management Index Register */
#define PMDR (io+1) /* Power Management Data Register */
/* Data Register indexes */
#define FER1 0x00 /* Function enable register 1 */
#define FER2 0x01 /* Function enable register 2 */
#define PMC1 0x02 /* Power Management Ctrl 1 */
#define PMC2 0x03 /* Power Management Ctrl 2 */
#define PMC3 0x04 /* Power Management Ctrl 3 */
#define WDTO 0x05 /* Watchdog timeout register */
#define WDCF 0x06 /* Watchdog config register */
#define WDST 0x07 /* Watchdog status register */
/* WDCF bitfields - which devices assert WDO */
#define KBC_IRQ 0x01 /* Keyboard Controller */
#define MSE_IRQ 0x02 /* Mouse */
#define UART1_IRQ 0x03 /* Serial0 */
#define UART2_IRQ 0x04 /* Serial1 */
/* 5 -7 are reserved */
static int timeout = 1;
static int io = -1;
static int io_len = 2; /* for non plug and play */
static unsigned long open_flag;
static char expect_close;
static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
#if defined CONFIG_PNP
static int isapnp = 1;
static struct pnp_dev *wdt_dev;
module_param(isapnp, int, 0);
MODULE_PARM_DESC(isapnp,
"When set to 0 driver ISA PnP support will be disabled");
#endif
module_param_hw(io, int, ioport, 0);
MODULE_PARM_DESC(io, "io port");
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/* Read from Data Register */
static inline void __sc1200wdt_read_data(unsigned char index,
unsigned char *data)
{
outb_p(index, PMIR);
*data = inb(PMDR);
}
static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
{
spin_lock(&sc1200wdt_lock);
__sc1200wdt_read_data(index, data);
spin_unlock(&sc1200wdt_lock);
}
/* Write to Data Register */
static inline void __sc1200wdt_write_data(unsigned char index,
unsigned char data)
{
outb_p(index, PMIR);
outb(data, PMDR);
}
static inline void sc1200wdt_write_data(unsigned char index,
unsigned char data)
{
spin_lock(&sc1200wdt_lock);
__sc1200wdt_write_data(index, data);
spin_unlock(&sc1200wdt_lock);
}
static void sc1200wdt_start(void)
{
unsigned char reg;
spin_lock(&sc1200wdt_lock);
__sc1200wdt_read_data(WDCF, ®);
/* assert WDO when any of the following interrupts are triggered too */
reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
__sc1200wdt_write_data(WDCF, reg);
/* set the timeout and get the ball rolling */
__sc1200wdt_write_data(WDTO, timeout);
spin_unlock(&sc1200wdt_lock);
}
static void sc1200wdt_stop(void)
{
sc1200wdt_write_data(WDTO, 0);
}
/* This returns the status of the WDO signal, inactive high. */
static inline int sc1200wdt_status(void)
{
unsigned char ret;
sc1200wdt_read_data(WDST, &ret);
/* If the bit is inactive, the watchdog is enabled, so return
* KEEPALIVEPING which is a bit of a kludge because there's nothing
* else for enabled/disabled status
*/
return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
}
static int sc1200wdt_open(struct inode *inode, struct file *file)
{
/* allow one at a time */
if (test_and_set_bit(0, &open_flag))
return -EBUSY;
if (timeout > MAX_TIMEOUT)
timeout = MAX_TIMEOUT;
sc1200wdt_start();
pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
return stream_open(inode, file);
}
static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int new_timeout;
void __user *argp = (void __user *)arg;
int __user *p = argp;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = "PC87307/PC97307",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
return put_user(sc1200wdt_status(), p);
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
{
int options, retval = -EINVAL;
if (get_user(options, p))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
sc1200wdt_stop();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
sc1200wdt_start();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
sc1200wdt_write_data(WDTO, timeout);
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, p))
return -EFAULT;
/* the API states this is given in secs */
new_timeout /= 60;
if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
return -EINVAL;
timeout = new_timeout;
sc1200wdt_write_data(WDTO, timeout);
fallthrough; /* and return the new timeout */
case WDIOC_GETTIMEOUT:
return put_user(timeout * 60, p);
default:
return -ENOTTY;
}
}
static int sc1200wdt_release(struct inode *inode, struct file *file)
{
if (expect_close == 42) {
sc1200wdt_stop();
pr_info("Watchdog disabled\n");
} else {
sc1200wdt_write_data(WDTO, timeout);
pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
}
clear_bit(0, &open_flag);
expect_close = 0;
return 0;
}
static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
expect_close = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
sc1200wdt_write_data(WDTO, timeout);
return len;
}
return 0;
}
static int sc1200wdt_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
sc1200wdt_stop();
return NOTIFY_DONE;
}
static struct notifier_block sc1200wdt_notifier = {
.notifier_call = sc1200wdt_notify_sys,
};
static const struct file_operations sc1200wdt_fops = {
.owner = THIS_MODULE,
.write = sc1200wdt_write,
.unlocked_ioctl = sc1200wdt_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = sc1200wdt_open,
.release = sc1200wdt_release,
};
static struct miscdevice sc1200wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &sc1200wdt_fops,
};
static int __init sc1200wdt_probe(void)
{
/* The probe works by reading the PMC3 register's default value of 0x0e
* there is one caveat, if the device disables the parallel port or any
* of the UARTs we won't be able to detect it.
* NB. This could be done with accuracy by reading the SID registers,
* but we don't have access to those io regions.
*/
unsigned char reg;
sc1200wdt_read_data(PMC3, ®);
reg &= 0x0f; /* we don't want the UART busy bits */
return (reg == 0x0e) ? 0 : -ENODEV;
}
#if defined CONFIG_PNP
static const struct pnp_device_id scl200wdt_pnp_devices[] = {
/* National Semiconductor PC87307/PC97307 watchdog component */
{.id = "NSC0800", .driver_data = 0},
{.id = ""},
};
static int scl200wdt_pnp_probe(struct pnp_dev *dev,
const struct pnp_device_id *dev_id)
{
/* this driver only supports one card at a time */
if (wdt_dev || !isapnp)
return -EBUSY;
wdt_dev = dev;
io = pnp_port_start(wdt_dev, 0);
io_len = pnp_port_len(wdt_dev, 0);
if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
pr_err("Unable to register IO port %#x\n", io);
return -EBUSY;
}
pr_info("PnP device found at io port %#x/%d\n", io, io_len);
return 0;
}
static void scl200wdt_pnp_remove(struct pnp_dev *dev)
{
if (wdt_dev) {
release_region(io, io_len);
wdt_dev = NULL;
}
}
static struct pnp_driver scl200wdt_pnp_driver = {
.name = "scl200wdt",
.id_table = scl200wdt_pnp_devices,
.probe = scl200wdt_pnp_probe,
.remove = scl200wdt_pnp_remove,
};
#endif /* CONFIG_PNP */
static int __init sc1200wdt_init(void)
{
int ret;
pr_info("%s\n", SC1200_MODULE_VER);
#if defined CONFIG_PNP
if (isapnp) {
ret = pnp_register_driver(&scl200wdt_pnp_driver);
if (ret)
goto out_clean;
}
#endif
if (io == -1) {
pr_err("io parameter must be specified\n");
ret = -EINVAL;
goto out_pnp;
}
#if defined CONFIG_PNP
/* now that the user has specified an IO port and we haven't detected
* any devices, disable pnp support */
if (isapnp)
pnp_unregister_driver(&scl200wdt_pnp_driver);
isapnp = 0;
#endif
if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
pr_err("Unable to register IO port %#x\n", io);
ret = -EBUSY;
goto out_pnp;
}
ret = sc1200wdt_probe();
if (ret)
goto out_io;
ret = register_reboot_notifier(&sc1200wdt_notifier);
if (ret) {
pr_err("Unable to register reboot notifier err = %d\n", ret);
goto out_io;
}
ret = misc_register(&sc1200wdt_miscdev);
if (ret) {
pr_err("Unable to register miscdev on minor %d\n",
WATCHDOG_MINOR);
goto out_rbt;
}
/* ret = 0 */
out_clean:
return ret;
out_rbt:
unregister_reboot_notifier(&sc1200wdt_notifier);
out_io:
release_region(io, io_len);
out_pnp:
#if defined CONFIG_PNP
if (isapnp)
pnp_unregister_driver(&scl200wdt_pnp_driver);
#endif
goto out_clean;
}
static void __exit sc1200wdt_exit(void)
{
misc_deregister(&sc1200wdt_miscdev);
unregister_reboot_notifier(&sc1200wdt_notifier);
#if defined CONFIG_PNP
if (isapnp)
pnp_unregister_driver(&scl200wdt_pnp_driver);
else
#endif
release_region(io, io_len);
}
module_init(sc1200wdt_init);
module_exit(sc1200wdt_exit);
MODULE_AUTHOR("Zwane Mwaikambo <[email protected]>");
MODULE_DESCRIPTION(
"Driver for National Semiconductor PC87307/PC97307 watchdog component");
MODULE_LICENSE("GPL");
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