/*
* 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 300641-004
*
* 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, ...
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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/init.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <linux/io.h>
/* Module and version information */
#define ESB_VERSION "0.05"
#define ESB_MODULE_NAME "i6300ESB timer"
#define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
/* 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 (0x03 << 0) /* Interrupt type on timer1 timeout */
/* Reload register bits */
#define ESB_WDT_TIMEOUT (0x01 << 9) /* Watchdog timed out */
#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 DEFINE_SPINLOCK(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;
/* We can only use 1 card due to the /dev/watchdog restriction */
static int cards_found;
/* module parameters */
/* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
#define WATCHDOG_HEARTBEAT 30
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 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 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)
{
writew(ESB_UNLOCK1, ESB_RELOAD_REG);
writew(ESB_UNLOCK2, ESB_RELOAD_REG);
}
static int esb_timer_start(void)
{
u8 val;
spin_lock(&esb_lock);
esb_unlock_registers();
writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
/* Enable or Enable + Lock? */
val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
spin_unlock(&esb_lock);
return 0;
}
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 & ESB_WDT_ENABLE;
}
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;
}
/*
* /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_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 {
pr_crit("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 long esb_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 = ESB_MODULE_NAME,
};
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &ident,
sizeof(ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
return put_user(0, p);
case WDIOC_GETBOOTSTATUS:
return put_user(triggered, p);
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_start();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
esb_timer_keepalive();
return 0;
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 -ENOTTY;
}
}
/*
* Kernel Interfaces
*/
static const struct file_operations esb_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = esb_write,
.unlocked_ioctl = esb_ioctl,
.open = esb_open,
.release = esb_release,
};
static struct miscdevice esb_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &esb_fops,
};
/*
* Data for PCI driver interface
*/
static DEFINE_PCI_DEVICE_TABLE(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 esb_getdevice(struct pci_dev *pdev)
{
if (pci_enable_device(pdev)) {
pr_err("failed to enable device\n");
goto err_devput;
}
if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
pr_err("failed to request region\n");
goto err_disable;
}
BASEADDR = pci_ioremap_bar(pdev, 0);
if (BASEADDR == NULL) {
/* Something's wrong here, BASEADDR has to be set */
pr_err("failed to get BASEADDR\n");
goto err_release;
}
/* Done */
esb_pci = pdev;
return 1;
err_release:
pci_release_region(pdev, 0);
err_disable:
pci_disable_device(pdev);
err_devput:
return 0;
}
static void esb_initdevice(void)
{
u8 val1;
u16 val2;
/*
* Config register:
* Bit 5 : 0 = Enable WDT_OUTPUT
* Bit 2 : 0 = set the timer frequency to the PCI clock
* divided by 2^15 (approx 1KHz).
* Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
* 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.
*/
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)
pr_warn("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);
if (val2 & ESB_WDT_TIMEOUT)
triggered = WDIOF_CARDRESET;
/* Reset WDT_TIMEOUT flag and timers */
esb_unlock_registers();
writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
/* And set the correct timeout value */
esb_timer_set_heartbeat(heartbeat);
}
static int esb_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
int ret;
cards_found++;
if (cards_found == 1)
pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
ESB_VERSION);
if (cards_found > 1) {
pr_err("This driver only supports 1 device\n");
return -ENODEV;
}
/* Check whether or not the hardware watchdog is there */
if (!esb_getdevice(pdev) || esb_pci == NULL)
return -ENODEV;
/* Check that the heartbeat value is within it's range;
if not reset to the default */
if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
heartbeat = WATCHDOG_HEARTBEAT;
pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
heartbeat);
}
/* Initialize the watchdog and make sure it does not run */
esb_initdevice();
/* Register the watchdog so that userspace has access to it */
ret = misc_register(&esb_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto err_unmap;
}
pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
BASEADDR, heartbeat, nowayout);
return 0;
err_unmap:
iounmap(BASEADDR);
pci_release_region(esb_pci, 0);
pci_disable_device(esb_pci);
esb_pci = NULL;
return ret;
}
static void esb_remove(struct pci_dev *pdev)
{
/* Stop the timer before we leave */
if (!nowayout)
esb_timer_stop();
/* Deregister */
misc_deregister(&esb_miscdev);
iounmap(BASEADDR);
pci_release_region(esb_pci, 0);
pci_disable_device(esb_pci);
esb_pci = NULL;
}
static void esb_shutdown(struct pci_dev *pdev)
{
esb_timer_stop();
}
static struct pci_driver esb_driver = {
.name = ESB_MODULE_NAME,
.id_table = esb_pci_tbl,
.probe = esb_probe,
.remove = esb_remove,
.shutdown = esb_shutdown,
};
module_pci_driver(esb_driver);
MODULE_AUTHOR("Ross Biro and David Härdeman");
MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
