// SPDX-License-Identifier: GPL-2.0+
/*
* NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
*
* This code is based on wdt.c with original copyright.
*
* (C) Copyright 2006 Sven Anders, <anders@anduras.de>
* and Marcus Junker, <junker@anduras.de>
*
* Neither Sven Anders, Marcus Junker nor ANDURAS AG
* admit liability nor provide warranty for any of this software.
* This material is provided "AS-IS" and at no charge.
*
* Release 1.1
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/io.h>
#include <linux/uaccess.h>
/* #define DEBUG 1 */
#define DEFAULT_TIMEOUT 1 /* 1 minute */
#define MAX_TIMEOUT 255
#define VERSION "1.1"
#define MODNAME "pc87413 WDT"
#define DPFX MODNAME " - DEBUG: "
#define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */
#define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1)
#define SWC_LDN 0x04
#define SIOCFG2 0x22 /* Serial IO register */
#define WDCTL 0x10 /* Watchdog-Timer-Control-Register */
#define WDTO 0x11 /* Watchdog timeout register */
#define WDCFG 0x12 /* Watchdog config register */
#define IO_DEFAULT 0x2E /* Address used on Portwell Boards */
static int io = IO_DEFAULT;
static int swc_base_addr = -1;
static int timeout = DEFAULT_TIMEOUT; /* timeout value */
static unsigned long timer_enabled; /* is the timer enabled? */
static char expect_close; /* is the close expected? */
static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */
static bool nowayout = WATCHDOG_NOWAYOUT;
/* -- Low level function ----------------------------------------*/
/* Select pins for Watchdog output */
static inline void pc87413_select_wdt_out(void)
{
unsigned int cr_data = 0;
/* Step 1: Select multiple pin,pin55,as WDT output */
outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
cr_data = inb(WDT_DATA_IO_PORT);
cr_data |= 0x80; /* Set Bit7 to 1*/
outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
outb_p(cr_data, WDT_DATA_IO_PORT);
#ifdef DEBUG
pr_info(DPFX
"Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
cr_data);
#endif
}
/* Enable SWC functions */
static inline void pc87413_enable_swc(void)
{
unsigned int cr_data = 0;
/* Step 2: Enable SWC functions */
outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */
outb_p(SWC_LDN, WDT_DATA_IO_PORT);
outb_p(0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */
cr_data = inb(WDT_DATA_IO_PORT);
cr_data |= 0x01; /* Set Bit0 to 1 */
outb_p(0x30, WDT_INDEX_IO_PORT);
outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */
#ifdef DEBUG
pr_info(DPFX "pc87413 - Enable SWC functions\n");
#endif
}
/* Read SWC I/O base address */
static void pc87413_get_swc_base_addr(void)
{
unsigned char addr_l, addr_h = 0;
/* Step 3: Read SWC I/O Base Address */
outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */
addr_h = inb(WDT_DATA_IO_PORT);
outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */
addr_l = inb(WDT_DATA_IO_PORT);
swc_base_addr = (addr_h << 8) + addr_l;
#ifdef DEBUG
pr_info(DPFX
"Read SWC I/O Base Address: low %d, high %d, res %d\n",
addr_l, addr_h, swc_base_addr);
#endif
}
/* Select Bank 3 of SWC */
static inline void pc87413_swc_bank3(void)
{
/* Step 4: Select Bank3 of SWC */
outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
#ifdef DEBUG
pr_info(DPFX "Select Bank3 of SWC\n");
#endif
}
/* Set watchdog timeout to x minutes */
static inline void pc87413_programm_wdto(char pc87413_time)
{
/* Step 5: Programm WDTO, Twd. */
outb_p(pc87413_time, swc_base_addr + WDTO);
#ifdef DEBUG
pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
#endif
}
/* Enable WDEN */
static inline void pc87413_enable_wden(void)
{
/* Step 6: Enable WDEN */
outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
#ifdef DEBUG
pr_info(DPFX "Enable WDEN\n");
#endif
}
/* Enable SW_WD_TREN */
static inline void pc87413_enable_sw_wd_tren(void)
{
/* Enable SW_WD_TREN */
outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
#ifdef DEBUG
pr_info(DPFX "Enable SW_WD_TREN\n");
#endif
}
/* Disable SW_WD_TREN */
static inline void pc87413_disable_sw_wd_tren(void)
{
/* Disable SW_WD_TREN */
outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
#ifdef DEBUG
pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
#endif
}
/* Enable SW_WD_TRG */
static inline void pc87413_enable_sw_wd_trg(void)
{
/* Enable SW_WD_TRG */
outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
#ifdef DEBUG
pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
#endif
}
/* Disable SW_WD_TRG */
static inline void pc87413_disable_sw_wd_trg(void)
{
/* Disable SW_WD_TRG */
outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
#ifdef DEBUG
pr_info(DPFX "Disable SW_WD_TRG\n");
#endif
}
/* -- Higher level functions ------------------------------------*/
/* Enable the watchdog */
static void pc87413_enable(void)
{
spin_lock(&io_lock);
pc87413_swc_bank3();
pc87413_programm_wdto(timeout);
pc87413_enable_wden();
pc87413_enable_sw_wd_tren();
pc87413_enable_sw_wd_trg();
spin_unlock(&io_lock);
}
/* Disable the watchdog */
static void pc87413_disable(void)
{
spin_lock(&io_lock);
pc87413_swc_bank3();
pc87413_disable_sw_wd_tren();
pc87413_disable_sw_wd_trg();
pc87413_programm_wdto(0);
spin_unlock(&io_lock);
}
/* Refresh the watchdog */
static void pc87413_refresh(void)
{
spin_lock(&io_lock);
pc87413_swc_bank3();
pc87413_disable_sw_wd_tren();
pc87413_disable_sw_wd_trg();
pc87413_programm_wdto(timeout);
pc87413_enable_wden();
pc87413_enable_sw_wd_tren();
pc87413_enable_sw_wd_trg();
spin_unlock(&io_lock);
}
/* -- File operations -------------------------------------------*/
/**
* pc87413_open:
* @inode: inode of device
* @file: file handle to device
*
*/
static int pc87413_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &timer_enabled))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
/* Reload and activate timer */
pc87413_refresh();
pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
return stream_open(inode, file);
}
/**
* pc87413_release:
* @inode: inode to board
* @file: file handle to board
*
* The watchdog has a configurable API. There is a religious dispute
* between people who want their watchdog to be able to shut down and
* those who want to be sure if the watchdog manager dies the machine
* reboots. In the former case we disable the counters, in the latter
* case you have to open it again very soon.
*/
static int pc87413_release(struct inode *inode, struct file *file)
{
/* Shut off the timer. */
if (expect_close == 42) {
pc87413_disable();
pr_info("Watchdog disabled, sleeping again...\n");
} else {
pr_crit("Unexpected close, not stopping watchdog!\n");
pc87413_refresh();
}
clear_bit(0, &timer_enabled);
expect_close = 0;
return 0;
}
/**
* pc87413_status:
*
* return, if the watchdog is enabled (timeout is set...)
*/
static int pc87413_status(void)
{
return 0; /* currently not supported */
}
/**
* pc87413_write:
* @file: file handle to the watchdog
* @data: data buffer to write
* @len: length in bytes
* @ppos: pointer to the position to write. No seeks allowed
*
* A write to a watchdog device is defined as a keepalive signal. Any
* write of data will do, as we we don't define content meaning.
*/
static ssize_t pc87413_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/* See if we got the magic character 'V' and reload the timer */
if (len) {
if (!nowayout) {
size_t i;
/* reset expect flag */
expect_close = 0;
/* scan to see whether or not we got the
magic character */
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
/* someone wrote to us, we should reload the timer */
pc87413_refresh();
}
return len;
}
/**
* pc87413_ioctl:
* @file: file handle to the device
* @cmd: watchdog command
* @arg: argument pointer
*
* The watchdog API defines a common set of functions for all watchdogs
* according to their available features. We only actually usefully support
* querying capabilities and current status.
*/
static long pc87413_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int new_timeout;
union {
struct watchdog_info __user *ident;
int __user *i;
} uarg;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING |
WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = "PC87413(HF/F) watchdog",
};
uarg.i = (int __user *)arg;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(uarg.ident, &ident,
sizeof(ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
return put_user(pc87413_status(), uarg.i);
case WDIOC_GETBOOTSTATUS:
return put_user(0, uarg.i);
case WDIOC_SETOPTIONS:
{
int options, retval = -EINVAL;
if (get_user(options, uarg.i))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
pc87413_disable();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
pc87413_enable();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
pc87413_refresh();
#ifdef DEBUG
pr_info(DPFX "keepalive\n");
#endif
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, uarg.i))
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;
pc87413_refresh();
fallthrough; /* and return the new timeout */
case WDIOC_GETTIMEOUT:
new_timeout = timeout * 60;
return put_user(new_timeout, uarg.i);
default:
return -ENOTTY;
}
}
/* -- Notifier funtions -----------------------------------------*/
/**
* notify_sys:
* @this: our notifier block
* @code: the event being reported
* @unused: unused
*
* Our notifier is called on system shutdowns. We want to turn the card
* off at reboot otherwise the machine will reboot again during memory
* test or worse yet during the following fsck. This would suck, in fact
* trust me - if it happens it does suck.
*/
static int pc87413_notify_sys(struct notifier_block *this,
unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
/* Turn the card off */
pc87413_disable();
return NOTIFY_DONE;
}
/* -- Module's structures ---------------------------------------*/
static const struct file_operations pc87413_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = pc87413_write,
.unlocked_ioctl = pc87413_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = pc87413_open,
.release = pc87413_release,
};
static struct notifier_block pc87413_notifier = {
.notifier_call = pc87413_notify_sys,
};
static struct miscdevice pc87413_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &pc87413_fops,
};
/* -- Module init functions -------------------------------------*/
/**
* pc87413_init: module's "constructor"
*
* Set up the WDT watchdog board. All we have to do is grab the
* resources we require and bitch if anyone beat us to them.
* The open() function will actually kick the board off.
*/
static int __init pc87413_init(void)
{
int ret;
pr_info("Version " VERSION " at io 0x%X\n",
WDT_INDEX_IO_PORT);
if (!request_muxed_region(io, 2, MODNAME))
return -EBUSY;
ret = register_reboot_notifier(&pc87413_notifier);
if (ret != 0)
pr_err("cannot register reboot notifier (err=%d)\n", ret);
ret = misc_register(&pc87413_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto reboot_unreg;
}
pr_info("initialized. timeout=%d min\n", timeout);
pc87413_select_wdt_out();
pc87413_enable_swc();
pc87413_get_swc_base_addr();
if (!request_region(swc_base_addr, 0x20, MODNAME)) {
pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
ret = -EBUSY;
goto misc_unreg;
}
pc87413_enable();
release_region(io, 2);
return 0;
misc_unreg:
misc_deregister(&pc87413_miscdev);
reboot_unreg:
unregister_reboot_notifier(&pc87413_notifier);
release_region(io, 2);
return ret;
}
/**
* pc87413_exit: module's "destructor"
*
* Unload the watchdog. You cannot do this with any file handles open.
* If your watchdog is set to continue ticking on close and you unload
* it, well it keeps ticking. We won't get the interrupt but the board
* will not touch PC memory so all is fine. You just have to load a new
* module in 60 seconds or reboot.
*/
static void __exit pc87413_exit(void)
{
/* Stop the timer before we leave */
if (!nowayout) {
pc87413_disable();
pr_info("Watchdog disabled\n");
}
misc_deregister(&pc87413_miscdev);
unregister_reboot_notifier(&pc87413_notifier);
release_region(swc_base_addr, 0x20);
pr_info("watchdog component driver removed\n");
}
module_init(pc87413_init);
module_exit(pc87413_exit);
MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
MODULE_AUTHOR("Marcus Junker <junker@anduras.de>");
MODULE_DESCRIPTION("PC87413 WDT driver");
MODULE_LICENSE("GPL");
module_param_hw(io, int, ioport, 0);
MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
__MODULE_STRING(IO_DEFAULT) ").");
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in minutes (default="
__MODULE_STRING(DEFAULT_TIMEOUT) ").");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
