openwrtv3/target/linux/amazon-2.6/files/drivers/char/amazon_wdt.c

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/*
* Infineon AP DC COM Amazon WDT driver
* Copyright 2004 Wu Qi Ming <gokimi@msn.com>
* All rights reserved
*/
#if defined(MODVERSIONS)
#include <linux/modversions.h>
#endif
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/tty.h>
#include <linux/selection.h>
#include <linux/kmod.h>
#include <linux/vmalloc.h>
#include <linux/kdev_t.h>
#include <linux/ioctl.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/amazon/amazon.h>
#include <asm/amazon/amazon_wdt.h>
#define AMAZON_WDT_EMSG(fmt, args...) printk( "%s: " fmt, __FUNCTION__ , ##args)
extern unsigned int amazon_get_fpi_hz(void);
/* forward declarations for _fops */
static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *offset);
static ssize_t wdt_write(struct file *file, const char *buf, size_t count, loff_t *offset);
static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg);
static int wdt_open(struct inode *inode, struct file *file);
static int wdt_release(struct inode *inode, struct file *file);
static int wdt_proc_read(char *buf, char **start, off_t offset,int count, int *eof, void *data);
static struct file_operations wdt_fops = {
read:wdt_read,
write:wdt_write,
ioctl:wdt_ioctl,
open:wdt_open,
release:wdt_release,
};
/* data */
static struct wdt_dev *amazon_wdt_dev;
static struct proc_dir_entry* amazon_wdt_dir;
static int occupied=0;
/* Brief: enable WDT
* Parameter:
timeout: time interval for WDT
* Return:
0 OK
EINVAL
* Describes:
1. Password Access
2. Modify Access (change ENDINIT => 0)
3. Change WDT_CON1 (enable WDT)
4. Password Access again
5. Modify Access (change ENDINIT => 1)
*/
int wdt_enable(int timeout)
{
u32 hard_psw,ffpi;
int reload_value, divider=0;
ffpi = amazon_get_fpi_hz();
divider = 1;
if((reload_value=65536-timeout*ffpi/256)<0){
divider = 0;
reload_value=65536-timeout*ffpi/16384;
}
if (reload_value < 0){
AMAZON_WDT_EMSG("timeout too large %d\n", timeout);
return -EINVAL;
}
AMAZON_WDT_EMSG("timeout:%d reload_value: %8x\n", timeout, reload_value);
hard_psw=(AMAZON_WDT_REG32(AMAZON_WDT_CON0)&0xffffff01)+(AMAZON_WDT_REG32(AMAZON_WDT_CON1)&0xc)+ 0xf0;
AMAZON_WDT_REG32(AMAZON_WDT_CON0)=hard_psw;
wmb();
AMAZON_WDT_REG32(AMAZON_WDT_CON0)=(hard_psw&0xff00)+(reload_value<<16)+0xf2;
wmb();
AMAZON_WDT_REG32(AMAZON_WDT_CON1)=divider<<2;
wmb();
hard_psw=(AMAZON_WDT_REG32(AMAZON_WDT_CON0)&0xffffff01)+(AMAZON_WDT_REG32(AMAZON_WDT_CON1)&0xc)+ 0xf0;
AMAZON_WDT_REG32(AMAZON_WDT_CON0)=hard_psw;
wmb();
AMAZON_WDT_REG32(AMAZON_WDT_CON0)=(AMAZON_WDT_REG32(AMAZON_WDT_CON0)&0xffffff00)+0xf3;
wmb();
return 0;
}
/* Brief: Disable/stop WDT
*/
void wdt_disable(void)
{
u32 hard_psw=0;
hard_psw=(AMAZON_WDT_REG32(AMAZON_WDT_CON0)&0xffffff01)+(AMAZON_WDT_REG32(AMAZON_WDT_CON1)&0xc)+ 0xf0;
AMAZON_WDT_REG32(AMAZON_WDT_CON0)=hard_psw;
wmb();
AMAZON_WDT_REG32(AMAZON_WDT_CON0)=(AMAZON_WDT_REG32(AMAZON_WDT_CON0)&0xffffff00)+0xf2;
wmb();
AMAZON_WDT_REG32(AMAZON_WDT_CON1)|=8;
wmb();
hard_psw=(AMAZON_WDT_REG32(AMAZON_WDT_CON0)&0xffffff01)+(AMAZON_WDT_REG32(AMAZON_WDT_CON1)&0xc)+ 0xf0;
AMAZON_WDT_REG32(AMAZON_WDT_CON0)=hard_psw;
wmb();
AMAZON_WDT_REG32(AMAZON_WDT_CON0)=(AMAZON_WDT_REG32(AMAZON_WDT_CON0)&0xffffff00)+0xf3;
wmb();
return;
}
static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
int result=0;
static int timeout=-1;
switch(cmd){
case AMAZON_WDT_IOC_START:
AMAZON_WDT_DMSG("enable watch dog timer!\n");
if ( copy_from_user((void*)&timeout, (void*)arg, sizeof (int)) ){
AMAZON_WDT_EMSG("invalid argument\n");
result=-EINVAL;
}else{
if ((result = wdt_enable(timeout)) < 0){
timeout = -1;
}
}
break;
case AMAZON_WDT_IOC_STOP:
AMAZON_WDT_DMSG("disable watch dog timer\n");
timeout = -1;
wdt_disable();
break;
case AMAZON_WDT_IOC_PING:
if (timeout <0 ){
result = -EIO;
}else{
result = wdt_enable(timeout);
}
}
return result;
}
static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *offset)
{
return 0;
}
static ssize_t wdt_write(struct file *file, const char *buf, size_t count, loff_t *offset)
{
return count;
}
static int wdt_open(struct inode *inode, struct file *file)
{
AMAZON_WDT_DMSG("wdt_open\n");
if (occupied == 1) return -EBUSY;
occupied = 1;
return 0;
}
static int wdt_release(struct inode *inode, struct file *file)
{
AMAZON_WDT_DMSG("wdt_release\n");
occupied = 0;
return 0;
}
int wdt_register_proc_read(char *buf, char **start, off_t offset,
int count, int *eof, void *data)
{
int len=0;
printk("wdt_registers:\n");
len+=sprintf(buf+len,"NMISR: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_NMISR));
len+=sprintf(buf+len,"RST_REQ: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_RST_REQ));
len+=sprintf(buf+len,"RST_SR: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_RST_SR));
len+=sprintf(buf+len,"WDT_CON0: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_CON0));
len+=sprintf(buf+len,"WDT_CON1: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_CON1));
len+=sprintf(buf+len,"WDT_SR: 0x%08x\n",AMAZON_WDT_REG32(AMAZON_WDT_SR));
*eof = 1;
return len;
}
int __init amazon_wdt_init_module(void)
{
int result=0;
amazon_wdt_dev = (wdt_dev*)kmalloc(sizeof(wdt_dev),GFP_KERNEL);
if (amazon_wdt_dev == NULL){
return -ENOMEM;
}
memset(amazon_wdt_dev,0,sizeof(wdt_dev));
amazon_wdt_dev->major=result;
strcpy(amazon_wdt_dev->name,"wdt");
result = register_chrdev(0,amazon_wdt_dev->name,&wdt_fops);
if (result < 0) {
AMAZON_WDT_EMSG("cannot register device\n");
kfree(amazon_wdt_dev);
return result;
}
amazon_wdt_dir=proc_mkdir("amazon_wdt",NULL);
create_proc_read_entry("wdt_register",
0,
amazon_wdt_dir,
wdt_register_proc_read,
NULL);
occupied=0;
return 0;
}
void amazon_wdt_cleanup_module(void)
{
unregister_chrdev(amazon_wdt_dev->major,amazon_wdt_dev->name);
kfree(amazon_wdt_dev);
remove_proc_entry("wdt_register",amazon_wdt_dir);
remove_proc_entry("amazon_wdt",NULL);
AMAZON_WDT_DMSG("unloaded\n");
return;
}
MODULE_LICENSE ("GPL");
MODULE_AUTHOR("Infineon IFAP DC COM");
MODULE_DESCRIPTION("AMAZON WDT driver");
module_init(amazon_wdt_init_module);
module_exit(amazon_wdt_cleanup_module);