pc87413_wdt.c

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/*
 *      NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
 *
 *      This code is based on wdt.c with original copyright.
 *
 *      (C) Copyright 2006 Sven Anders, <[e-mail]>
 *                     and Marcus Junker, <[e-mail]>
 *
 *      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.
 *
 *      Neither Sven Anders, Marcus Junker nor ANDURAS AG
 *      admit liability nor provide warranty for any of this software.
 *      This material is provided "AS-IS" and at no charge.
 *
 *      Release 1.1
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/version.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>

/* #define DEBUG 1 */

#define DEFAULT_TIMEOUT     1            /* 1 minute */
#define MAX_TIMEOUT         255

#define VERSION             "1.1"
#define MODNAME             "pc87413 WDT"
#define PFX                 MODNAME ": "
#define DPFX                MODNAME " - DEBUG: "

#define WDT_INDEX_IO_PORT   (io+0)       /* I/O port base (index register) */
#define WDT_DATA_IO_PORT    (WDT_INDEX_IO_PORT+1)
#define SWC_LDN             0x04
#define SIOCFG2             0x22         /* Serial IO register */
#define WDCTL               0x10         /* Watchdog-Timer-Controll-Register */
#define WDTO                0x11         /* Watchdog timeout register */
#define WDCFG               0x12         /* Watchdog config register */

static int io = 0x2E;		         /* Address used on Portwell Boards */

static int timeout = DEFAULT_TIMEOUT;    /* timeout value */
static unsigned long timer_enabled = 0;  /* is the timer enabled? */

static char expect_close;                /* is the close expected? */

static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */

static int nowayout = WATCHDOG_NOWAYOUT;

/* -- Low level function ----------------------------------------*/

/* Select pins for Watchdog output */

static inline void pc87413_select_wdt_out (void)
{
	unsigned int cr_data = 0;

	/* Step 1: Select multiple pin,pin55,as WDT output */

	outb_p(SIOCFG2, WDT_INDEX_IO_PORT);

	cr_data = inb (WDT_DATA_IO_PORT);

	cr_data |= 0x80; /* Set Bit7 to 1*/
	outb_p(SIOCFG2, WDT_INDEX_IO_PORT);

	outb_p(cr_data, WDT_DATA_IO_PORT);

#ifdef DEBUG
	printk(KERN_INFO DPFX "Select multiple pin,pin55,as WDT output:"
	                      " Bit7 to 1: %d\n", cr_data);
#endif
}

/* Enable SWC functions */

static inline void pc87413_enable_swc(void)
{
	unsigned int cr_data=0;

	/* Step 2: Enable SWC functions */

	outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
	outb_p(SWC_LDN, WDT_DATA_IO_PORT);

	outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
	cr_data = inb(WDT_DATA_IO_PORT);
	cr_data |= 0x01;                        /* Set Bit0 to 1 */
	outb_p(0x30, WDT_INDEX_IO_PORT);
	outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */

#ifdef DEBUG
	printk(KERN_INFO DPFX "pc87413 - Enable SWC functions\n");
#endif
}

/* Read SWC I/O base address */

static inline unsigned int pc87413_get_swc_base(void)
{
	unsigned int  swc_base_addr = 0;
	unsigned char addr_l, addr_h = 0;

	/* Step 3: Read SWC I/O Base Address */

	outb_p(0x60, WDT_INDEX_IO_PORT);        /* Read Index 0x60 */
	addr_h = inb(WDT_DATA_IO_PORT);

	outb_p(0x61, WDT_INDEX_IO_PORT);        /* Read Index 0x61 */

	addr_l = inb(WDT_DATA_IO_PORT);

	swc_base_addr = (addr_h << 8) + addr_l;

#ifdef DEBUG
	printk(KERN_INFO DPFX "Read SWC I/O Base Address: low %d, high %d,"
	                      " res %d\n", addr_l, addr_h, swc_base_addr);
#endif

	return swc_base_addr;
}

/* Select Bank 3 of SWC */

static inline void pc87413_swc_bank3(unsigned int swc_base_addr)
{
	/* Step 4: Select Bank3 of SWC */

	outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);

#ifdef DEBUG
	printk(KERN_INFO DPFX "Select Bank3 of SWC\n");
#endif
}

/* Set watchdog timeout to x minutes */

static inline void pc87413_programm_wdto(unsigned int swc_base_addr,
					 char pc87413_time)
{
	/* Step 5: Programm WDTO, Twd. */

	outb_p(pc87413_time, swc_base_addr + WDTO);

#ifdef DEBUG
	printk(KERN_INFO DPFX "Set WDTO to %d minutes\n", pc87413_time);
#endif
}

/* Enable WDEN */

static inline void pc87413_enable_wden(unsigned int swc_base_addr)
{
	/* Step 6: Enable WDEN */

	outb_p(inb (swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);

#ifdef DEBUG
	printk(KERN_INFO DPFX "Enable WDEN\n");
#endif
}

/* Enable SW_WD_TREN */
static inline void pc87413_enable_sw_wd_tren(unsigned int swc_base_addr)
{
	/* Enable SW_WD_TREN */

	outb_p(inb (swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);

#ifdef DEBUG
	printk(KERN_INFO DPFX "Enable SW_WD_TREN\n");
#endif
}

/* Disable SW_WD_TREN */

static inline void pc87413_disable_sw_wd_tren(unsigned int swc_base_addr)
{
	/* Disable SW_WD_TREN */

	outb_p(inb (swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);

#ifdef DEBUG
	printk(KERN_INFO DPFX "pc87413 - Disable SW_WD_TREN\n");
#endif
}

/* Enable SW_WD_TRG */

static inline void pc87413_enable_sw_wd_trg(unsigned int swc_base_addr)
{
	/* Enable SW_WD_TRG */

	outb_p(inb (swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);

#ifdef DEBUG
	printk(KERN_INFO DPFX "pc87413 - Enable SW_WD_TRG\n");
#endif
}

/* Disable SW_WD_TRG */

static inline void pc87413_disable_sw_wd_trg(unsigned int swc_base_addr)
{
	/* Disable SW_WD_TRG */

	outb_p(inb (swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);

#ifdef DEBUG
	printk(KERN_INFO DPFX "Disable SW_WD_TRG\n");
#endif
}

/* -- Higher level functions ------------------------------------*/

/* Enable the watchdog */

static void pc87413_enable(void)
{
	unsigned int swc_base_addr;

	spin_lock(&io_lock);

	pc87413_select_wdt_out();
	pc87413_enable_swc();
	swc_base_addr = pc87413_get_swc_base();
	pc87413_swc_bank3(swc_base_addr);
	pc87413_programm_wdto(swc_base_addr, timeout);
	pc87413_enable_wden(swc_base_addr);
	pc87413_enable_sw_wd_tren(swc_base_addr);
	pc87413_enable_sw_wd_trg(swc_base_addr);

	spin_unlock(&io_lock);
}

/* Disable the watchdog */

static void pc87413_disable(void)
{
	unsigned int swc_base_addr;

	spin_lock(&io_lock);

	pc87413_select_wdt_out();
	pc87413_enable_swc();
	swc_base_addr = pc87413_get_swc_base();
	pc87413_swc_bank3(swc_base_addr);
	pc87413_disable_sw_wd_tren(swc_base_addr);
	pc87413_disable_sw_wd_trg(swc_base_addr);
	pc87413_programm_wdto(swc_base_addr, 0);

	spin_unlock(&io_lock);
}

/* Refresh the watchdog */

static void pc87413_refresh(void)
{
	unsigned int swc_base_addr;

	spin_lock(&io_lock);

	pc87413_select_wdt_out();
	pc87413_enable_swc();
	swc_base_addr = pc87413_get_swc_base();
	pc87413_swc_bank3(swc_base_addr);
	pc87413_disable_sw_wd_tren(swc_base_addr);
	pc87413_disable_sw_wd_trg(swc_base_addr);
	pc87413_programm_wdto(swc_base_addr, timeout);
	pc87413_enable_wden(swc_base_addr);
	pc87413_enable_sw_wd_tren(swc_base_addr);
	pc87413_enable_sw_wd_trg(swc_base_addr);

	spin_unlock(&io_lock);
}

/* -- File operations -------------------------------------------*/

/**
 *	pc87413_open:
 *	@inode: inode of device
 *	@file: file handle to device
 *
 */

static int pc87413_open(struct inode *inode, struct file *file)
{
	/* /dev/watchdog can only be opened once */

	if (test_and_set_bit(0, &timer_enabled))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	/* Reload and activate timer */
	pc87413_refresh();

	printk(KERN_INFO MODNAME "Watchdog enabled. Timeout set to"