/*
    i2c-viapro.c - Part of lm_sensors, Linux kernel modules for hardware
              monitoring
    Copyright (c) 1998 - 2001  Frodo Looijaard <frodol@dds.nl>, 
    Philip Edelbrock <phil@netroedge.com>, Kyösti Mälkki <kmalkki@cc.hut.fi>,
    Mark D. Studebaker <mdsxyz123@yahoo.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.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
   Supports Via devices:
	82C596A/B (0x3050)
	82C596B (0x3051)
	82C686A/B
	8233
   Note: we assume there can only be one device, with one SMBus interface.
*/

#include <linux/version.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <asm/io.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/i2c.h>
#define LM_DATE "20011118"
#define LM_VERSION "2.6.2"
#include <linux/init.h>

#ifdef MODULE_LICENSE
MODULE_LICENSE("GPL");
#endif

#ifndef PCI_DEVICE_ID_VIA_82C596_3
#define PCI_DEVICE_ID_VIA_82C596_3 	0x3050
#endif
#ifndef PCI_DEVICE_ID_VIA_82C596B_3
#define PCI_DEVICE_ID_VIA_82C596B_3	0x3051
#endif
#ifndef PCI_DEVICE_ID_VIA_82C686_4
#define PCI_DEVICE_ID_VIA_82C686_4 	0x3057
#endif
#ifndef PCI_DEVICE_ID_VIA_8233_0
#define PCI_DEVICE_ID_VIA_8233_0	0x3074
#endif

#define SMBBA1	    0x90
#define SMBBA2      0x80
#define SMBBA3      0xD0

struct sd {
	const unsigned short dev;
	const unsigned char base;
	const unsigned char hstcfg;
	const char *name;
};

static struct sd supported[] = {
	{PCI_DEVICE_ID_VIA_82C596_3, SMBBA1, 0xD2, "VT82C596A/B"},
	{PCI_DEVICE_ID_VIA_82C596B_3, SMBBA1, 0xD2, "VT82C596B"},
	{PCI_DEVICE_ID_VIA_82C686_4, SMBBA1, 0xD2, "VT82C686A/B"},
	{PCI_DEVICE_ID_VIA_8233_0, SMBBA3, 0xD2, "VT8233"},
	{0, 0, 0, NULL}
};

static struct sd *num = supported;

/* SMBus address offsets */
#define SMBHSTSTS (0 + vt596_smba)
#define SMBHSLVSTS (1 + vt596_smba)
#define SMBHSTCNT (2 + vt596_smba)
#define SMBHSTCMD (3 + vt596_smba)
#define SMBHSTADD (4 + vt596_smba)
#define SMBHSTDAT0 (5 + vt596_smba)
#define SMBHSTDAT1 (6 + vt596_smba)
#define SMBBLKDAT (7 + vt596_smba)
#define SMBSLVCNT (8 + vt596_smba)
#define SMBSHDWCMD (9 + vt596_smba)
#define SMBSLVEVT (0xA + vt596_smba)
#define SMBSLVDAT (0xC + vt596_smba)

/* PCI Address Constants */

/* SMBus data in configuration space can be found in two places,
   We try to select the better one*/

static unsigned short smb_cf_hstcfg;

#define SMBHSTCFG   (smb_cf_hstcfg)
#define SMBSLVC     (SMBHSTCFG+1)
#define SMBSHDW1    (SMBHSTCFG+2)
#define SMBSHDW2    (SMBHSTCFG+3)
#define SMBREV      (SMBHSTCFG+4)

/* Other settings */
#define MAX_TIMEOUT 500
#define  ENABLE_INT9 0

/* VT82C596 constants */
#define VT596_QUICK      0x00
#define VT596_BYTE       0x04
#define VT596_BYTE_DATA  0x08
#define VT596_WORD_DATA  0x0C
#define VT596_BLOCK_DATA 0x14

/* insmod parameters */

/* If force is set to anything different from 0, we forcibly enable the
   VT596. DANGEROUS! */
static int force = 0;
MODULE_PARM(force, "i");
MODULE_PARM_DESC(force, "Forcibly enable the SMBus. DANGEROUS!");

/* If force_addr is set to anything different from 0, we forcibly enable
   the VT596 at the given address. VERY DANGEROUS! */
static int force_addr = 0;
MODULE_PARM(force_addr, "i");
MODULE_PARM_DESC(force_addr,
		 "Forcibly enable the SMBus at the given address. "
		 "EXTREMELY DANGEROUS!");

#ifdef MODULE
static
#else
extern
#endif
int __init i2c_vt596_init(void);
static int __init vt596_cleanup(void);
static int vt596_setup(void);
static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
			unsigned short flags, char read_write,
			u8 command, int size, union i2c_smbus_data *data);
static void vt596_do_pause(unsigned int amount);
static int vt596_transaction(void);
static void vt596_inc(struct i2c_adapter *adapter);
static void vt596_dec(struct i2c_adapter *adapter);
static u32 vt596_func(struct i2c_adapter *adapter);

#ifdef MODULE
extern int init_module(void);
extern int cleanup_module(void);
#endif				/* MODULE */

static struct i2c_algorithm smbus_algorithm = {
	/* name */ "Non-I2C SMBus adapter",
	/* id */ I2C_ALGO_SMBUS,
	/* master_xfer */ NULL,
	/* smbus_access */ vt596_access,
	/* slave_send */ NULL,
	/* slave_rcv */ NULL,
	/* algo_control */ NULL,
	/* functionality */ vt596_func,
};

static struct i2c_adapter vt596_adapter = {
	"unset",
	I2C_ALGO_SMBUS | I2C_HW_SMBUS_VIA2,
	&smbus_algorithm,
	NULL,
	vt596_inc,
	vt596_dec,
	NULL,
	NULL,
};

static int __initdata vt596_initialized;
static unsigned short vt596_smba = 0;


/* Detect whether a compatible device can be found, and initialize it. */
int vt596_setup(void)
{
	unsigned char temp;

	struct pci_dev *VT596_dev = NULL;

	/* First check whether we can access PCI at all */
	if (pci_present() == 0)
		return(-ENODEV);

	/* Look for a supported device/function */
	do {
		if((VT596_dev = pci_find_device(PCI_VENDOR_ID_VIA, num->dev,
					        VT596_dev)))
			break;
	} while ((++num)->dev);

	if (VT596_dev == NULL)
		return(-ENODEV);
	printk("i2c-viapro.o: Found Via %s device\n", num->name);

/* Determine the address of the SMBus areas */
	smb_cf_hstcfg = num->hstcfg;
	if (force_addr) {
		vt596_smba = force_addr;
		force = 0;
	} else {
		if ((pci_read_config_word(VT596_dev, num->base, &vt596_smba))
		    || !(vt596_smba & 0x1)) {
			/* try 2nd address and config reg. for 596 */
			if((num->dev == PCI_DEVICE_ID_VIA_82C596_3) &&
			   (!pci_read_config_word(VT596_dev, SMBBA2, &vt596_smba)) &&
			   (vt596_smba & 0x1)) {
				smb_cf_hstcfg = 0x84;
			} else {
			        /* no matches at all */
			        printk("i2c-viapro.o: Cannot configure SMBus "
				       "I/O Base address\n");
			        return(-ENODEV);
			}
		}
	}
	vt596_smba &= 0xfff0;

	if (check_region(vt596_smba, 8)) {
		printk("i2c-viapro.o: SMB region 0x%x already in use!\n",
		        vt596_smba);
		return(-ENODEV);
	}

	pci_read_config_byte(VT596_dev, SMBHSTCFG, &temp);
/* If force_addr is set, we program the new address here. Just to make
   sure, we disable the VT596 first. */
	if (force_addr) {
		pci_write_config_byte(VT596_dev, SMBHSTCFG, temp & 0xfe);
		pci_write_config_word(VT596_dev, num->base, vt596_smba);
		pci_write_config_byte(VT596_dev, SMBHSTCFG, temp | 0x01);
		printk
		    ("i2c-viapro.o: WARNING: SMBus interface set to new "
		     "address 0x%04x!\n", vt596_smba);
	} else if ((temp & 1) == 0) {
		if (force) {
/* NOTE: This assumes I/O space and other allocations WERE
   done by the Bios!  Don't complain if your hardware does weird 
   things after enabling this. :') Check for Bios updates before
   resorting to this.  */
			pci_write_config_byte(VT596_dev, SMBHSTCFG,
					      temp | 1);
			printk
			    ("i2c-viapro.o: WARNING: SMBus interface has been FORCEFULLY "
			     "ENABLED!\n");
		} else {
			printk
			    ("SMBUS: Error: Host SMBus controller not enabled!\n");
			return(-ENODEV);
		}
	}

	/* Everything is happy, let's grab the memory and set things up. */
	request_region(vt596_smba, 8, "via2-smbus");

#ifdef DEBUG
	if ((temp & 0x0E) == 8)
		printk("i2c-viapro.o: using Interrupt 9 for SMBus.\n");
	else if ((temp & 0x0E) == 0)
		printk("i2c-viapro.o: using Interrupt SMI# for SMBus.\n");
	else
		printk
		    ("i2c-viapro.o: Illegal Interrupt configuration (or code out "
		     "of date)!\n");

	pci_read_config_byte(VT596_dev, SMBREV, &temp);
	printk("i2c-viapro.o: SMBREV = 0x%X\n", temp);
	printk("i2c-viapro.o: VT596_smba = 0x%X\n", vt596_smba);
#endif				/* DEBUG */

	return(0);
}


/* Internally used pause function */
void vt596_do_pause(unsigned int amount)
{
	current->state = TASK_INTERRUPTIBLE;
	schedule_timeout(amount);
}

/* Another internally used function */
int vt596_transaction(void)
{
	int temp;
	int result = 0;
	int timeout = 0;

#ifdef DEBUG
	printk
	    ("i2c-viapro.o: Transaction (pre): CNT=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, "
	     "DAT1=%02x\n", inb_p(SMBHSTCNT), inb_p(SMBHSTCMD),
	     inb_p(SMBHSTADD), inb_p(SMBHSTDAT0), inb_p(SMBHSTDAT1));
#endif

	/* Make sure the SMBus host is ready to start transmitting */
	if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
#ifdef DEBUG
		printk("i2c-viapro.o: SMBus busy (0x%02x). Resetting... \n",
		       temp);
#endif
		outb_p(temp, SMBHSTSTS);
		if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
#ifdef DEBUG
			printk("i2c-viapro.o: Failed! (0x%02x)\n", temp);
#endif
			return -1;
		} else {
#ifdef DEBUG
			printk("i2c-viapro.o: Successfull!\n");
#endif
		}
	}

	/* start the transaction by setting bit 6 */
	outb_p(inb(SMBHSTCNT) | 0x040, SMBHSTCNT);

	/* We will always wait for a fraction of a second! 
	   I don't know if VIA needs this, Intel did  */
	do {
		vt596_do_pause(1);
		temp = inb_p(SMBHSTSTS);
	} while ((temp & 0x01) && (timeout++ < MAX_TIMEOUT));

	/* If the SMBus is still busy, we give up */
	if (timeout >= MAX_TIMEOUT) {
#ifdef DEBUG
		printk("i2c-viapro.o: SMBus Timeout!\n");
		result = -1;
#endif
	}

	if (temp & 0x10) {
		result = -1;
#ifdef DEBUG
		printk("i2c-viapro.o: Error: Failed bus transaction\n");
#endif
	}

	if (temp & 0x08) {
		result = -1;
		printk
		    ("i2c-viapro.o: Bus collision! SMBus may be locked until next hard\n"
		     "reset. (sorry!)\n");
		/* Clock stops and slave is stuck in mid-transmission */
	}

	if (temp & 0x04) {
		result = -1;
#ifdef DEBUG
		printk("i2c-viapro.o: Error: no response!\n");
#endif
	}

	if (inb_p(SMBHSTSTS) != 0x00)
		outb_p(inb(SMBHSTSTS), SMBHSTSTS);

	if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
#ifdef DEBUG
		printk
		    ("i2c-viapro.o: Failed reset at end of transaction (%02x)\n",
		     temp);
#endif
	}
#ifdef DEBUG
	printk
	    ("i2c-viapro.o: Transaction (post): CNT=%02x, CMD=%02x, ADD=%02x, "
	     "DAT0=%02x, DAT1=%02x\n", inb_p(SMBHSTCNT), inb_p(SMBHSTCMD),
	     inb_p(SMBHSTADD), inb_p(SMBHSTDAT0), inb_p(SMBHSTDAT1));
#endif
	return result;
}

/* Return -1 on error. See smbus.h for more information */
s32 vt596_access(struct i2c_adapter * adap, u16 addr, unsigned short flags,
		 char read_write,
		 u8 command, int size, union i2c_smbus_data * data)
{
	int i, len;

	switch (size) {
	case I2C_SMBUS_PROC_CALL:
		printk
		    ("i2c-viapro.o: I2C_SMBUS_PROC_CALL not supported!\n");
		return -1;
	case I2C_SMBUS_QUICK:
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		size = VT596_QUICK;
		break;
	case I2C_SMBUS_BYTE:
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		if (read_write == I2C_SMBUS_WRITE)
			outb_p(command, SMBHSTCMD);
		size = VT596_BYTE;
		break;
	case I2C_SMBUS_BYTE_DATA:
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		outb_p(command, SMBHSTCMD);
		if (read_write == I2C_SMBUS_WRITE)
			outb_p(data->byte, SMBHSTDAT0);
		size = VT596_BYTE_DATA;
		break;
	case I2C_SMBUS_WORD_DATA:
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		outb_p(command, SMBHSTCMD);
		if (read_write == I2C_SMBUS_WRITE) {
			outb_p(data->word & 0xff, SMBHSTDAT0);
			outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
		}
		size = VT596_WORD_DATA;
		break;
	case I2C_SMBUS_BLOCK_DATA:
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		outb_p(command, SMBHSTCMD);
		if (read_write == I2C_SMBUS_WRITE) {
			len = data->block[0];
			if (len < 0)
				len = 0;
			if (len > 32)
				len = 32;
			outb_p(len, SMBHSTDAT0);
			i = inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
			for (i = 1; i <= len; i++)
				outb_p(data->block[i], SMBBLKDAT);
		}
		size = VT596_BLOCK_DATA;
		break;
	}

	outb_p((size & 0x1C) + (ENABLE_INT9 & 1), SMBHSTCNT);

	if (vt596_transaction())	/* Error in transaction */
		return -1;

	if ((read_write == I2C_SMBUS_WRITE) || (size == VT596_QUICK))
		return 0;


	switch (size) {
	case VT596_BYTE:	/* Where is the result put? I assume here it is in
				   SMBHSTDAT0 but it might just as well be in the
				   SMBHSTCMD. No clue in the docs */

		data->byte = inb_p(SMBHSTDAT0);
		break;
	case VT596_BYTE_DATA:
		data->byte = inb_p(SMBHSTDAT0);
		break;
	case VT596_WORD_DATA:
		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
		break;
	case VT596_BLOCK_DATA:
		data->block[0] = inb_p(SMBHSTDAT0);
		i = inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
		for (i = 1; i <= data->block[0]; i++)
			data->block[i] = inb_p(SMBBLKDAT);
		break;
	}
	return 0;
}

void vt596_inc(struct i2c_adapter *adapter)
{
	MOD_INC_USE_COUNT;
}

void vt596_dec(struct i2c_adapter *adapter)
{

	MOD_DEC_USE_COUNT;
}

u32 vt596_func(struct i2c_adapter *adapter)
{
	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
	    I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
	    I2C_FUNC_SMBUS_BLOCK_DATA;
}

int __init i2c_vt596_init(void)
{
	int res;
	printk("i2c-viapro.o version %s (%s)\n", LM_VERSION, LM_DATE);
#ifdef DEBUG
/* PE- It might be good to make this a permanent part of the code! */
	if (vt596_initialized) {
		printk
		    ("i2c-viapro.o: Oops, vt596_init called a second time!\n");
		return -EBUSY;
	}
#endif
	vt596_initialized = 0;
	if ((res = vt596_setup())) {
		printk
		    ("i2c-viapro.o: Can't detect vt82c596 or compatible device, module not inserted.\n");
		vt596_cleanup();
		return res;
	}
	vt596_initialized++;
	sprintf(vt596_adapter.name, "SMBus Via Pro adapter at %04x",
		vt596_smba);
	if ((res = i2c_add_adapter(&vt596_adapter))) {
		printk
		    ("i2c-viapro.o: Adapter registration failed, module not inserted.\n");
		vt596_cleanup();
		return res;
	}
	vt596_initialized++;
	printk("i2c-viapro.o: Via Pro SMBus detected and initialized\n");
	return 0;
}

int __init vt596_cleanup(void)
{
	int res;
	if (vt596_initialized >= 2) {
		if ((res = i2c_del_adapter(&vt596_adapter))) {
			printk
			    ("i2c-viapro.o: i2c_del_adapter failed, module not removed\n");
			return res;
		} else
			vt596_initialized--;
	}
	if (vt596_initialized >= 1) {
		release_region(vt596_smba, 8);
		vt596_initialized--;
	}
	return 0;
}

EXPORT_NO_SYMBOLS;

#ifdef MODULE

MODULE_AUTHOR
    ("Frodo Looijaard <frodol@dds.nl> and Philip Edelbrock <phil@netroedge.com>");
MODULE_DESCRIPTION("vt82c596 SMBus driver");


int init_module(void)
{
	return i2c_vt596_init();
}

int cleanup_module(void)
{
	return vt596_cleanup();
}

#endif				/* MODULE */
