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linux/drivers/watchdog/i6300esb.c
Alexey Dobriyan c7dfd0cca3 [WATCHDOG] spin_lock_init() fixes 
Some watchdog drivers initialize global spinlocks in module's init function
which is tolerable, but some do it in PCI probe function.  So, switch to
static initialization to fix theoretical bugs and, more importantly, stop
giving people bad examples.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-11-02 19:09:07 +00:00

526 lines
14 KiB
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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 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;
/* 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=" __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) {
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 -ENOTTY;
}
}
/*
* 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 const 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;
/* 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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