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linux/drivers/char/watchdog/i6300esb.c

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/*
* i6300esb: Watchdog timer driver for Intel 6300ESB chipset
*
* (c) Copyright 2004 Google Inc.
* (c) Copyright 2005 David Härdeman <david@2gen.com>
*
* 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 of the License, or (at your option) any later version.
*
* based on i810-tco.c which is in turn based on softdog.c
*
* The timer is implemented in the following I/O controller hubs:
* (See the intel documentation on http://developer.intel.com.)
* 6300ESB chip : document number 300641-003
*
* 2004YYZZ Ross Biro
* Initial version 0.01
* 2004YYZZ Ross Biro
* Version 0.02
* 20050210 David Härdeman <david@2gen.com>
* Ported driver to kernel 2.6
*/
/*
* Includes, defines, variables, module parameters, ...
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <asm/uaccess.h>
#include <asm/io.h>
/* Module and version information */
#define ESB_VERSION "0.03"
#define ESB_MODULE_NAME "i6300ESB timer"
#define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
#define PFX ESB_MODULE_NAME ": "
/* PCI configuration registers */
#define ESB_CONFIG_REG 0x60 /* Config register */
#define ESB_LOCK_REG 0x68 /* WDT lock register */
/* Memory mapped registers */
#define ESB_TIMER1_REG BASEADDR + 0x00 /* Timer1 value after each reset */
#define ESB_TIMER2_REG BASEADDR + 0x04 /* Timer2 value after each reset */
#define ESB_GINTSR_REG BASEADDR + 0x08 /* General Interrupt Status Register */
#define ESB_RELOAD_REG BASEADDR + 0x0c /* Reload register */
/* Lock register bits */
#define ESB_WDT_FUNC ( 0x01 << 2 ) /* Watchdog functionality */
#define ESB_WDT_ENABLE ( 0x01 << 1 ) /* Enable WDT */
#define ESB_WDT_LOCK ( 0x01 << 0 ) /* Lock (nowayout) */
/* Config register bits */
#define ESB_WDT_REBOOT ( 0x01 << 5 ) /* Enable reboot on timeout */
#define ESB_WDT_FREQ ( 0x01 << 2 ) /* Decrement frequency */
#define ESB_WDT_INTTYPE ( 0x11 << 0 ) /* Interrupt type on timer1 timeout */
/* Reload register bits */
#define ESB_WDT_RELOAD ( 0x01 << 8 ) /* prevent timeout */
/* Magic constants */
#define ESB_UNLOCK1 0x80 /* Step 1 to unlock reset registers */
#define ESB_UNLOCK2 0x86 /* Step 2 to unlock reset registers */
/* internal variables */
static void __iomem *BASEADDR;
static spinlock_t esb_lock; /* Guards the hardware */
static unsigned long timer_alive;
static struct pci_dev *esb_pci;
static unsigned short triggered; /* The status of the watchdog upon boot */
static char esb_expect_close;
/* module parameters */
#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (1<heartbeat<2*1023) */
static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (1<heartbeat<2046, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
/*
* Some i6300ESB specific functions
*/
/*
* Prepare for reloading the timer by unlocking the proper registers.
* This is performed by first writing 0x80 followed by 0x86 to the
* reload register. After this the appropriate registers can be written
* to once before they need to be unlocked again.
*/
static inline void esb_unlock_registers(void) {
writeb(ESB_UNLOCK1, ESB_RELOAD_REG);
writeb(ESB_UNLOCK2, ESB_RELOAD_REG);
}
static void esb_timer_start(void)
{
u8 val;
/* Enable or Enable + Lock? */
val = 0x02 | (nowayout ? 0x01 : 0x00);
pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
}
static int esb_timer_stop(void)
{
u8 val;
spin_lock(&esb_lock);
/* First, reset timers as suggested by the docs */
esb_unlock_registers();
writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
/* Then disable the WDT */
pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
spin_unlock(&esb_lock);
/* Returns 0 if the timer was disabled, non-zero otherwise */
return (val & 0x01);
}
static void esb_timer_keepalive(void)
{
spin_lock(&esb_lock);
esb_unlock_registers();
writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
/* FIXME: Do we need to flush anything here? */
spin_unlock(&esb_lock);
}
static int esb_timer_set_heartbeat(int time)
{
u32 val;
if (time < 0x1 || time > (2 * 0x03ff))
return -EINVAL;
spin_lock(&esb_lock);
/* We shift by 9, so if we are passed a value of 1 sec,
* val will be 1 << 9 = 512, then write that to two
* timers => 2 * 512 = 1024 (which is decremented at 1KHz)
*/
val = time << 9;
/* Write timer 1 */
esb_unlock_registers();
writel(val, ESB_TIMER1_REG);
/* Write timer 2 */
esb_unlock_registers();
writel(val, ESB_TIMER2_REG);
/* Reload */
esb_unlock_registers();
writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
/* FIXME: Do we need to flush everything out? */
/* Done */
heartbeat = time;
spin_unlock(&esb_lock);
return 0;
}
static int esb_timer_read (void)
{
u32 count;
/* This isn't documented, and doesn't take into
* acount which stage is running, but it looks
* like a 20 bit count down, so we might as well report it.
*/
pci_read_config_dword(esb_pci, 0x64, &count);
return (int)count;
}
/*
* /dev/watchdog handling
*/
static int esb_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 */
esb_timer_keepalive ();
esb_timer_start ();
return nonseekable_open(inode, file);
}
static int esb_release (struct inode *inode, struct file *file)
{
/* Shut off the timer. */
if (esb_expect_close == 42) {
esb_timer_stop ();
} else {
printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
esb_timer_keepalive ();
}
clear_bit(0, &timer_alive);
esb_expect_close = 0;
return 0;
}
static ssize_t esb_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... */
esb_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')
esb_expect_close = 42;
}
}
/* someone wrote to us, we should reload the timer */
esb_timer_keepalive ();
}
return len;
}
static int esb_ioctl (struct inode *inode, 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 struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = ESB_MODULE_NAME,
};
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &ident,
sizeof (ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
return put_user (esb_timer_read(), p);
case WDIOC_GETBOOTSTATUS:
return put_user (triggered, p);
case WDIOC_KEEPALIVE:
esb_timer_keepalive ();
return 0;
case WDIOC_SETOPTIONS:
{
if (get_user (new_options, p))
return -EFAULT;
if (new_options & WDIOS_DISABLECARD) {
esb_timer_stop ();
retval = 0;
}
if (new_options & WDIOS_ENABLECARD) {
esb_timer_keepalive ();
esb_timer_start ();
retval = 0;
}
return retval;
}
case WDIOC_SETTIMEOUT:
{
if (get_user(new_heartbeat, p))
return -EFAULT;
if (esb_timer_set_heartbeat(new_heartbeat))
return -EINVAL;
esb_timer_keepalive ();
/* Fall */
}
case WDIOC_GETTIMEOUT:
return put_user(heartbeat, p);
default:
return -ENOIOCTLCMD;
}
}
/*
* Notify system
*/
static int esb_notify_sys (struct notifier_block *this, unsigned long code, void *unused)
{
if (code==SYS_DOWN || code==SYS_HALT) {
/* Turn the WDT off */
esb_timer_stop ();
}
return NOTIFY_DONE;
}
/*
* Kernel Interfaces
*/
static struct file_operations esb_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = esb_write,
.ioctl = esb_ioctl,
.open = esb_open,
.release = esb_release,
};
static struct miscdevice esb_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &esb_fops,
};
static struct notifier_block esb_notifier = {
.notifier_call = esb_notify_sys,
};
/*
* 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 struct pci_device_id esb_pci_tbl[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
{ 0, }, /* End of list */
};
MODULE_DEVICE_TABLE (pci, esb_pci_tbl);
/*
* Init & exit routines
*/
static unsigned char __init esb_getdevice (void)
{
u8 val1;
unsigned short val2;
struct pci_dev *dev = NULL;
/*
* Find the PCI device
*/
for_each_pci_dev(dev) {
if (pci_match_id(esb_pci_tbl, dev)) {
esb_pci = dev;
break;
}
}
if (esb_pci) {
if (pci_enable_device(esb_pci)) {
printk (KERN_ERR PFX "failed to enable device\n");
goto err_devput;
}
if (pci_request_region(esb_pci, 0, ESB_MODULE_NAME)) {
printk (KERN_ERR PFX "failed to request region\n");
goto err_disable;
}
BASEADDR = ioremap(pci_resource_start(esb_pci, 0),
pci_resource_len(esb_pci, 0));
if (BASEADDR == NULL) {
/* Something's wrong here, BASEADDR has to be set */
printk (KERN_ERR PFX "failed to get BASEADDR\n");
goto err_release;
}
/*
* The watchdog has two timers, it can be setup so that the
* expiry of timer1 results in an interrupt and the expiry of
* timer2 results in a reboot. We set it to not generate
* any interrupts as there is not much we can do with it
* right now.
*
* We also enable reboots and set the timer frequency to
* the PCI clock divided by 2^15 (approx 1KHz).
*/
pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
/* Check that the WDT isn't already locked */
pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
if (val1 & ESB_WDT_LOCK)
printk (KERN_WARNING PFX "nowayout already set\n");
/* Set the timer to watchdog mode and disable it for now */
pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
/* Check if the watchdog was previously triggered */
esb_unlock_registers();
val2 = readw(ESB_RELOAD_REG);
triggered = (val2 & (0x01 << 9) >> 9);
/* Reset trigger flag and timers */
esb_unlock_registers();
writew((0x11 << 8), ESB_RELOAD_REG);
/* Done */
return 1;
err_release:
pci_release_region(esb_pci, 0);
err_disable:
pci_disable_device(esb_pci);
err_devput:
pci_dev_put(esb_pci);
}
return 0;
}
static int __init watchdog_init (void)
{
int ret;
spin_lock_init(&esb_lock);
/* Check whether or not the hardware watchdog is there */
if (!esb_getdevice () || esb_pci == NULL)
return -ENODEV;
/* Check that the heartbeat value is within it's range ; if not reset to the default */
if (esb_timer_set_heartbeat (heartbeat)) {
esb_timer_set_heartbeat (WATCHDOG_HEARTBEAT);
printk(KERN_INFO PFX "heartbeat value must be 1<heartbeat<2046, using %d\n",
heartbeat);
}
ret = register_reboot_notifier(&esb_notifier);
if (ret != 0) {
printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
ret);
goto err_unmap;
}
ret = misc_register(&esb_miscdev);
if (ret != 0) {
printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto err_notifier;
}
esb_timer_stop ();
printk (KERN_INFO PFX "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
BASEADDR, heartbeat, nowayout);
return 0;
err_notifier:
unregister_reboot_notifier(&esb_notifier);
err_unmap:
iounmap(BASEADDR);
/* err_release: */
pci_release_region(esb_pci, 0);
/* err_disable: */
pci_disable_device(esb_pci);
/* err_devput: */
pci_dev_put(esb_pci);
return ret;
}
static void __exit watchdog_cleanup (void)
{
/* Stop the timer before we leave */
if (!nowayout)
esb_timer_stop ();
/* Deregister */
misc_deregister(&esb_miscdev);
unregister_reboot_notifier(&esb_notifier);
iounmap(BASEADDR);
pci_release_region(esb_pci, 0);
pci_disable_device(esb_pci);
pci_dev_put(esb_pci);
}
module_init(watchdog_init);
module_exit(watchdog_cleanup);
MODULE_AUTHOR("Ross Biro and David Härdeman");
MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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