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|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* nv_tco 0.01: TCO timer driver for NV chipsets
*
* (c) Copyright 2005 Google Inc., All Rights Reserved.
*
* Based off i8xx_tco.c:
* (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
* Reserved.
* https://www.kernelconcepts.de
*
* TCO timer driver for NV chipsets
* based on softdog.c by Alan Cox <alan@redhat.com>
*/
/*
* Includes, defines, variables, module parameters, ...
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/platform_device.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "nv_tco.h"
/* Module and version information */
#define TCO_VERSION "0.01"
#define TCO_MODULE_NAME "NV_TCO"
#define TCO_DRIVER_NAME TCO_MODULE_NAME ", v" TCO_VERSION
/* internal variables */
static unsigned int tcobase;
static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */
static unsigned long timer_alive;
static char tco_expect_close;
static struct pci_dev *tco_pci;
/* the watchdog platform device */
static struct platform_device *nv_tco_platform_device;
/* module parameters */
#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (2<heartbeat<39) */
static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
"default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
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) ")");
/*
* Some TCO specific functions
*/
static inline unsigned char seconds_to_ticks(int seconds)
{
/* the internal timer is stored as ticks which decrement
* every 0.6 seconds */
return (seconds * 10) / 6;
}
static void tco_timer_start(void)
{
u32 val;
unsigned long flags;
spin_lock_irqsave(&tco_lock, flags);
val = inl(TCO_CNT(tcobase));
val &= ~TCO_CNT_TCOHALT;
outl(val, TCO_CNT(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
}
static void tco_timer_stop(void)
{
u32 val;
unsigned long flags;
spin_lock_irqsave(&tco_lock, flags);
val = inl(TCO_CNT(tcobase));
val |= TCO_CNT_TCOHALT;
outl(val, TCO_CNT(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
}
static void tco_timer_keepalive(void)
{
unsigned long flags;
spin_lock_irqsave(&tco_lock, flags);
outb(0x01, TCO_RLD(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
}
static int tco_timer_set_heartbeat(int t)
{
int ret = 0;
unsigned char tmrval;
unsigned long flags;
u8 val;
/*
* note seconds_to_ticks(t) > t, so if t > 0x3f, so is
* tmrval=seconds_to_ticks(t). Check that the count in seconds isn't
* out of range on it's own (to avoid overflow in tmrval).
*/
if (t < 0 || t > 0x3f)
return -EINVAL;
tmrval = seconds_to_ticks(t);
/* "Values of 0h-3h are ignored and should not be attempted" */
if (tmrval > 0x3f || tmrval < 0x04)
return -EINVAL;
/* Write new heartbeat to watchdog */
spin_lock_irqsave(&tco_lock, flags);
val = inb(TCO_TMR(tcobase));
val &= 0xc0;
val |= tmrval;
outb(val, TCO_TMR(tcobase));
val = inb(TCO_TMR(tcobase));
if ((val & 0x3f) != tmrval)
ret = -EINVAL;
spin_unlock_irqrestore(&tco_lock, flags);
if (ret)
return ret;
heartbeat = t;
return 0;
}
/*
* /dev/watchdog handling
*/
static int nv_tco_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &timer_alive))
return -EBUSY;
/* Reload and activate timer */
tco_timer_keepalive();
tco_timer_start();
return stream_open(inode, file);
}
static int nv_tco_release(struct inode *inode, struct file *file)
{
/* Shut off the timer */
if (tco_expect_close == 42) {
tco_timer_stop();
} else {
pr_crit("Unexpected close, not stopping watchdog!\n");
tco_timer_keepalive();
}
clear_bit(0, &timer_alive);
tco_expect_close = 0;
return 0;
}
static ssize_t nv_tco_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;
/*
* note: just in case someone wrote the magic character
* five months ago...
*/
tco_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')
tco_expect_close = 42;
}
}
/* someone wrote to us, we should reload the timer */
tco_timer_keepalive();
}
return len;
}
static long nv_tco_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int new_options, retval = -EINVAL;
int new_heartbeat;
void __user *argp = (void __user *)arg;
int __user *p = argp;
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = TCO_MODULE_NAME,
};
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:
if (get_user(new_options, p))
return -EFAULT;
if (new_options & WDIOS_DISABLECARD) {
tco_timer_stop();
retval = 0;
}
if (new_options & WDIOS_ENABLECARD) {
tco_timer_keepalive();
tco_timer_start();
retval = 0;
}
return retval;
case WDIOC_KEEPALIVE:
tco_timer_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_heartbeat, p))
return -EFAULT;
if (tco_timer_set_heartbeat(new_heartbeat))
return -EINVAL;
tco_timer_keepalive();
fallthrough;
case WDIOC_GETTIMEOUT:
return put_user(heartbeat, p);
default:
return -ENOTTY;
}
}
/*
* Kernel Interfaces
*/
static const struct file_operations nv_tco_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = nv_tco_write,
.unlocked_ioctl = nv_tco_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = nv_tco_open,
.release = nv_tco_release,
};
static struct miscdevice nv_tco_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &nv_tco_fops,
};
/*
* Data for PCI driver interface
*
* This data only exists for exporting the supported
* PCI ids via MODULE_DEVICE_TABLE. We do not actually
* register a pci_driver, because someone else might one day
* want to register another driver on the same PCI id.
*/
static const struct pci_device_id
|