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// SPDX-License-Identifier: GPL-2.0-only
/*
* ALi M7101 PMU Computer Watchdog Timer driver
*
* Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>
* and the Cobalt kernel WDT timer driver by Tim Hockin
* <thockin@cobaltnet.com>
*
* (c)2002 Steve Hill <steve@navaho.co.uk>
*
* This WDT driver is different from most other Linux WDT
* drivers in that the driver will ping the watchdog by itself,
* because this particular WDT has a very short timeout (1.6
* seconds) and it would be insane to count on any userspace
* daemon always getting scheduled within that time frame.
*
* Additions:
* Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
* found on very old cobalt hardware.
* -- Mike Waychison <michael.waychison@sun.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#define WDT_ENABLE 0x9C
#define WDT_DISABLE 0x8C
#define ALI_7101_WDT 0x92
#define ALI_7101_GPIO 0x7D
#define ALI_7101_GPIO_O 0x7E
#define ALI_WDT_ARM 0x01
/*
* We're going to use a 1 second timeout.
* If we reset the watchdog every ~250ms we should be safe. */
#define WDT_INTERVAL (HZ/4+1)
/*
* We must not require too good response from the userspace daemon.
* Here we require the userspace daemon to send us a heartbeat
* char to /dev/watchdog every 30 seconds.
*/
#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. (1<=timeout<=3600, default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
static int use_gpio; /* Use the pic (for a1d revision alim7101) */
module_param(use_gpio, int, 0);
MODULE_PARM_DESC(use_gpio,
"Use the gpio watchdog (required by old cobalt boards).");
static void wdt_timer_ping(struct timer_list *);
static DEFINE_TIMER(timer, wdt_timer_ping);
static unsigned long next_heartbeat;
static unsigned long wdt_is_open;
static char wdt_expect_close;
static struct pci_dev *alim7101_pmu;
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) ")");
/*
* Whack the dog
*/
static void wdt_timer_ping(struct timer_list *unused)
{
/* If we got a heartbeat pulse within the WDT_US_INTERVAL
* we agree to ping the WDT
*/
char tmp;
if (time_before(jiffies, next_heartbeat)) {
/* Ping the WDT (this is actually a disarm/arm sequence) */
pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
pci_write_config_byte(alim7101_pmu,
ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
pci_write_config_byte(alim7101_pmu,
ALI_7101_WDT, (tmp | ALI_WDT_ARM));
if (use_gpio) {
pci_read_config_byte(alim7101_pmu,
ALI_7101_GPIO_O, &tmp);
pci_write_config_byte(alim7101_pmu,
ALI_7101_GPIO_O, tmp | 0x20);
pci_write_config_byte(alim7101_pmu,
ALI_7101_GPIO_O, tmp & ~0x20);
}
} else {
pr_warn("Heartbeat lost! Will not ping the watchdog\n");
}
/* Re-set the timer interval */
mod_timer(&timer, jiffies + WDT_INTERVAL);
}
/*
* Utility routines
*/
static void wdt_change(int writeval)
{
char tmp;
pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
if (writeval == WDT_ENABLE) {
pci_write_config_byte(alim7101_pmu,
ALI_7101_WDT, (tmp | ALI_WDT_ARM));
if (use_gpio) {
pci_read_config_byte(alim7101_pmu,
ALI_7101_GPIO_O, &tmp);
pci_write_config_byte(alim7101_pmu,
ALI_7101_GPIO_O, tmp & ~0x20);
}
} else {
pci_write_config_byte(alim7101_pmu,
ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
if (use_gpio) {
pci_read_config_byte(alim7101_pmu,
ALI_7101_GPIO_O, &tmp);
pci_write_config_byte(alim7101_pmu,
ALI_7101_GPIO_O, tmp | 0x20);
}
}
}
static void wdt_startup(void)
{
next_heartbeat = jiffies + (timeout * HZ);
/* We must enable before we kick off the timer in case the timer
occurs as we ping it */
wdt_change(WDT_ENABLE);
/* Start the timer */
mod_timer(&timer, jiffies + WDT_INTERVAL);
pr_info("Watchdog timer is now enabled\n");
}
static void wdt_turnoff(void)
{
/* Stop the timer */
del_timer_sync(&timer);
wdt_change(WDT_DISABLE);
pr_info("Watchdog timer is now disabled...\n");
}
static void wdt_keepalive(void)
{
/* user land ping */
next_heartbeat = jiffies + (timeout * HZ);
}
/*
* /dev/watchdog handling
*/
static ssize_t fop_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
/* See if we got the magic character 'V' and reload the timer */
if (count) {
if (!nowayout) {
size_t ofs;
/* note: just in case someone wrote the magic character
* five months ago... */
wdt_expect_close = 0;
/* now scan */
for (ofs = 0; ofs != count; ofs++) {
char c;
if (get_user(c, buf + ofs))
return -EFAULT;
if (c == 'V')
wdt_expect_close = 42;
}
}
/* someone wrote to us, we should restart timer */
wdt_keepalive();
}
return count;
}
static int fop_open(struct inode *inode, struct file *file)
{
/* Just in case we're already talking to someone... */
if (test_and_set_bit(0, &wdt_is_open))
return -EBUSY;
/* Good, fire up the show */
wdt_startup();
return stream_open(inode, file);
}
static int fop_close(struct inode *inode, struct file *file)
{
if (wdt_expect_close == 42)
wdt_turnoff();
else {
/* wim: shouldn't there be a: del_timer(&timer); */
pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
}
clear_bit(0, &wdt_is_open);
wdt_expect_close = 0;
return 0;
}
static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
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 = 1,
.identity = "ALiM7101",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
{
int new_options, retval = -EINVAL;
if (get_user(new_options, p))
return -EFAULT;
if (new_options & WDIOS_DISABLECARD) {
wdt_turnoff();
retval = 0;
}
if (new_options & WDIOS_ENABLECARD) {
wdt_startup();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
wdt_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
{
int new_timeout;
if (get_user(new_timeout, p))
return -EFAULT;
/* arbitrary upper limit */
if (new_timeout < 1 || new_timeout > 3600)
return -EINVAL;
timeout = new_timeout;
wdt_keepalive();
}
/* Fall through */
case WDIOC_GETTIMEOUT:
return put_user(timeout, p);
default:
return -ENOTTY;
}
}
static const struct file_operations wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = fop_write,
.open = fop_open,
.release = fop_close,
.unlocked_ioctl = fop_ioctl,
};
static struct miscdevice wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wdt_fops,
};
static int wdt_restart_handle(struct notifier_block *this, unsigned long mode,
void *cmd)
{
/*
* Cobalt devices have no way of rebooting themselves other
* than getting the watchdog to pull reset, so we restart the
* watchdog on reboot with no heartbeat.
*/
wdt_change(WDT_ENABLE);
/* loop until the watchdog fires */
while (true)
;
return NOTIFY_DONE;
}
static struct notifier_block wdt_restart_handler = {
.notifier_call = wdt_restart_handle,
.priority = 128,
};
/*
* Notifier for system down
*/
static int wdt_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
wdt_turnoff();
return NOTIFY_DONE;
}
/*
* The WDT needs to learn about soft shutdowns in order to
* turn the timebomb registers off.
*/
static struct notifier_block wdt_notifier = {
.notifier_call = wdt_notify_sys,
};
static void __exit alim7101_wdt_unload(void)
{
wdt_turnoff();
/* Deregister */
misc_deregister(&wdt_miscdev);
unregister_reboot_notifier(&wdt_notifier);
unregister_restart_handler(&wdt_restart_handler);
pci_dev_put(alim7101_pmu);
}
static int __init alim7101_wdt_init(void)
{
int rc = -EBUSY;
struct pci_dev *ali1543_south;
char tmp;
pr_info("Steve Hill <steve@navaho.co.uk>\n");
alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
NULL);
if (!alim7101_pmu) {
pr_info("ALi M7101 PMU not present - WDT not set\n");
return -EBUSY;
}
/* Set the WDT in the PMU to 1 second */
pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
NULL);
if (!ali1543_south) {
pr_info("ALi 1543 South-Bridge not present - WDT not set\n");
goto err_out;
}
pci_read_config_byte(ali1543_south, 0x5e, &tmp);
pci_dev_put(ali1543_south);
if ((tmp & 0x1e) == 0x00) {
if (!use_gpio) {
pr_info("Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n");
goto err_out;
}
nowayout = 1;
} else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
goto err_out;
}
if (timeout < 1 || timeout > 3600) {
/* arbitrary upper limit */
timeout = WATCHDOG_TIMEOUT;
pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
timeout);
}
rc = register_reboot_notifier(&wdt_notifier);
if (rc) {
pr_err("cannot register reboot notifier (err=%d)\n", rc);
goto err_out;
}
rc = register_restart_handler(&wdt_restart_handler);
if (rc) {
pr_err("cannot register restart handler (err=%d)\n", rc);
goto err_out_reboot;
}
rc = misc_register(&wdt_miscdev);
if (rc) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
wdt_miscdev.minor, rc);
goto err_out_restart;
}
if (nowayout)
__module_get(THIS_MODULE);
pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
timeout, nowayout);
return 0;
err_out_restart:
unregister_restart_handler(&wdt_restart_handler);
err_out_reboot:
unregister_reboot_notifier(&wdt_notifier);
err_out:
pci_dev_put(alim7101_pmu);
return rc;
}
module_init(alim7101_wdt_init);
module_exit(alim7101_wdt_unload);
static const struct pci_device_id alim7101_pci_tbl[] __used = {
{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
{ }
};
MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
MODULE_AUTHOR("Steve Hill");
MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
MODULE_LICENSE("GPL");
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