/*
    i801.c - Part of lm_sensors, Linux kernel modules for hardware
              monitoring
    Copyright (c) 1998 - 2002  Frodo Looijaard <frodol@dds.nl>,
    Philip Edelbrock <phil@netroedge.com>, and 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.
*/

/*
    SUPPORTED DEVICES	PCI ID
    82801AA		2413           
    82801AB		2423           
    82801BA		2443           
    82801CA/CAM		2483           
    82801DB		24C3   (HW PEC supported, 32 byte buffer not supported)

    This driver supports several versions of Intel's I/O Controller Hubs (ICH).
    For SMBus support, they are similar to the PIIX4 and are part
    of Intel's '810' and other chipsets.
    See the doc/busses/i2c-i801 file for details.
    I2C Block Read and Process Call are not supported.
*/

/* Note: we assume there can only be one I801, with one SMBus interface */

/* #define DEBUG 1 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <asm/io.h>

#ifdef I2C_FUNC_SMBUS_BLOCK_DATA_PEC
#define HAVE_PEC
#endif

/* I801 SMBus address offsets */
#define SMBHSTSTS	(0 + i801_smba)
#define SMBHSTCNT	(2 + i801_smba)
#define SMBHSTCMD	(3 + i801_smba)
#define SMBHSTADD	(4 + i801_smba)
#define SMBHSTDAT0	(5 + i801_smba)
#define SMBHSTDAT1	(6 + i801_smba)
#define SMBBLKDAT	(7 + i801_smba)
#define SMBPEC		(8 + i801_smba)	/* ICH4 only */
#define SMBAUXSTS	(12 + i801_smba)	/* ICH4 only */
#define SMBAUXCTL	(13 + i801_smba)	/* ICH4 only */

/* PCI Address Constants */
#define SMBBA		0x020
#define SMBHSTCFG	0x040
#define SMBREV		0x008

/* Host configuration bits for SMBHSTCFG */
#define SMBHSTCFG_HST_EN	1
#define SMBHSTCFG_SMB_SMI_EN	2
#define SMBHSTCFG_I2C_EN	4

/* Other settings */
#define MAX_TIMEOUT		100
#define ENABLE_INT9		0	/* set to 0x01 to enable - untested */

/* I801 command constants */
#define I801_QUICK		0x00
#define I801_BYTE		0x04
#define I801_BYTE_DATA		0x08
#define I801_WORD_DATA		0x0C
#define I801_PROC_CALL		0x10	/* later chips only, unimplemented */
#define I801_BLOCK_DATA		0x14
#define I801_I2C_BLOCK_DATA	0x18	/* unimplemented */
#define I801_BLOCK_LAST		0x34
#define I801_I2C_BLOCK_LAST	0x38	/* unimplemented */
#define I801_START		0x40
#define I801_PEC_EN		0x80	/* ICH4 only */

/* insmod parameters */

/* If force_addr is set to anything different from 0, we forcibly enable
   the I801 at the given address. VERY DANGEROUS! */
static int force_addr = 0;
MODULE_PARM(force_addr, "i");
MODULE_PARM_DESC(force_addr,
		 "Forcibly enable the I801 at the given address. "
		 "EXTREMELY DANGEROUS!");

static void i801_do_pause(unsigned int amount);
static int i801_transaction(void);
static int i801_block_transaction(union i2c_smbus_data *data,
				  char read_write, int command);

static unsigned short i801_smba;
static struct pci_dev *I801_dev;
static int isich4;

static int i801_setup(struct pci_dev *dev)
{
	int error_return = 0;
	unsigned char temp;

	/* Note: we keep on searching until we have found 'function 3' */
	if(PCI_FUNC(dev->devfn) != 3)
		return -ENODEV;

	I801_dev = dev;
	if (dev->device == PCI_DEVICE_ID_INTEL_82801DB_3)
		isich4 = 1;
	else
		isich4 = 0;

	/* Determine the address of the SMBus areas */
	if (force_addr) {
		i801_smba = force_addr & 0xfff0;
	} else {
		pci_read_config_word(I801_dev, SMBBA, &i801_smba);
		i801_smba &= 0xfff0;
		if(i801_smba == 0) {
			dev_err(&dev->dev, "SMB base address uninitialized"
				"- upgrade BIOS or use force_addr=0xaddr\n");
			return -ENODEV;
		}
	}

	if (!request_region(i801_smba, (isich4 ? 16 : 8), "i801-smbus")) {
		dev_err(&dev->dev, "I801_smb region 0x%x already in use!\n",
			i801_smba);
		error_return = -EBUSY;
		goto END;
	}

	pci_read_config_byte(I801_dev, SMBHSTCFG, &temp);
	temp &= ~SMBHSTCFG_I2C_EN;	/* SMBus timing */
	pci_write_config_byte(I801_dev, SMBHSTCFG, temp);

	/* If force_addr is set, we program the new address here. Just to make
	   sure, we disable the device first. */
	if (force_addr) {
		pci_write_config_byte(I801_dev, SMBHSTCFG, temp & 0xfe);
		pci_write_config_word(I801_dev, SMBBA, i801_smba);
		pci_write_config_byte(I801_dev, SMBHSTCFG, temp | 0x01);
		dev_warn(&dev->dev, "WARNING: I801 SMBus interface set to "
			"new address %04x!\n", i801_smba);
	} else if ((temp & 1) == 0) {
		pci_write_config_byte(I801_dev, SMBHSTCFG, temp | 1);
		dev_warn(&dev->dev, "enabling SMBus device\n");
	}

	if (temp & 0x02)
		dev_dbg(&dev->dev, "I801 using Interrupt SMI# for SMBus.\n");
	else
		dev_dbg(&dev->dev, "I801 using PCI Interrupt for SMBus.\n");

	pci_read_config_byte(I801_dev, SMBREV, &temp);
	dev_dbg(&dev->dev, "SMBREV = 0x%X\n", temp);
	dev_dbg(&dev->dev, "I801_smba = 0x%X\n", i801_smba);

END:
	return error_return;
}


static void i801_do_pause(unsigned int amount)
{
	current->state = TASK_INTERRUPTIBLE;
	schedule_timeout(amount);
}

static int i801_transaction(void)
{
	int temp;
	int result = 0;
	int timeout = 0;

	dev_dbg(&I801_dev->dev, "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));

	/* Make sure the SMBus host is ready to start transmitting */
	/* 0x1f = Failed, Bus_Err, Dev_Err, Intr, Host_Busy */
	if ((temp = (0x1f & inb_p(SMBHSTSTS))) != 0x00) {
		dev_dbg(&I801_dev->dev, "SMBus busy (%02x). Resetting... \n",
			temp);
		outb_p(temp, SMBHSTSTS);
		if ((temp = (0x1f & inb_p(SMBHSTSTS))) != 0x00) {
			dev_dbg(&I801_dev->dev, "Failed! (%02x)\n", temp);
			return -1;
		} else {
			dev_dbg(&I801_dev->dev, "Successfull!\n");
		}
	}

	outb_p(inb(SMBHSTCNT) | I801_START, SMBHSTCNT);

	/* We will always wait for a fraction of a second! */
	do {
		i801_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) {
		dev_dbg(&I801_dev->dev, "SMBus Timeout!\n");
		result = -1;
	}

	if (temp & 0x10) {
		result = -1;
		dev_dbg(&I801_dev->dev, "Error: Failed bus transaction\n");
	}

	if (temp & 0x08) {
		result = -1;
		dev_err(&I801_dev->dev, "Bus collision! SMBus may be locked "
			"until next hard reset. (sorry!)\n");
		/* Clock stops and slave is stuck in mid-transmission */
	}

	if (temp & 0x04) {
		result = -1;
		dev_dbg(&I801_dev->dev, "Error: no response!\n");
	}

	if ((inb_p(SMBHSTSTS) & 0x1f) != 0x00)
		outb_p(inb(SMBHSTSTS), SMBHSTSTS);

	if ((temp = (0x1f & inb_p(SMBHSTSTS))) != 0x00) {
		dev_dbg(&I801_dev->dev, "Failed reset at end of transaction"
			"(%02x)\n", temp);
	}
	dev_dbg(&I801_dev->dev, "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));
	return result;
}

/* All-inclusive block transaction function */
static int i801_block_transaction(union i2c_smbus_data *data, char read_write,
				  int command)
{
	int i, len;
	int smbcmd;
	int temp;
	int result = 0;
	int timeout;
	unsigned char hostc, errmask;

	if (command == I2C_SMBUS_I2C_BLOCK_DATA) {
		if (read_write == I2C_SMBUS_WRITE) {
			/* set I2C_EN bit in configuration register */
			pci_read_config_byte(I801_dev, SMBHSTCFG, &hostc);
			pci_write_config_byte(I801_dev, SMBHSTCFG,
					      hostc | SMBHSTCFG_I2C_EN);
		} else {
			dev_err(&I801_dev->dev,
				"I2C_SMBUS_I2C_BLOCK_READ not DB!\n");
			return -1;
		}
	}

	if (read_write == I2C_SMBUS_WRITE) {
		len = data->block[0];
		if (len < 1)
			len = 1;
		if (len > 32)
			len = 32;
		outb_p(len, SMBHSTDAT0);
		outb_p(data->block[1], SMBBLKDAT);
	} else {
		len = 32;	/* max for reads */
	}

	if(isich4 && command != I2C_SMBUS_I2C_BLOCK_DATA) {
		/* set 32 byte buffer */
	}

	for (i = 1; i <= len; i++) {
		if (i == len && read_write == I2C_SMBUS_READ)
			smbcmd = I801_BLOCK_LAST;
		else
			smbcmd = I801_BLOCK_DATA;
		outb_p(smbcmd | ENABLE_INT9, SMBHSTCNT);

		dev_dbg(&I801_dev->dev, "Block (pre %d): CNT=%02x, CMD=%02x, "
			"ADD=%02x, DAT0=%02x, BLKDAT=%02x\n", i,
			inb_p(SMBHSTCNT), inb_p(SMBHSTCMD), inb_p(SMBHSTADD),
			inb_p(SMBHSTDAT0), inb_p(SMBBLKDAT));

		/* Make sure the SMBus host is ready to start transmitting */
		temp = inb_p(SMBHSTSTS);
		if (i == 1) {
			/* Erronenous conditions before transaction: 
			 * Byte_Done, Failed, Bus_Err, Dev_Err, Intr, Host_Busy */
			errmask=0x9f; 
		} else {
			/* Erronenous conditions during transaction: 
			 * Failed, Bus_Err, Dev_Err, Intr */
			errmask=0x1e; 
		}
		if (temp & errmask) {
			dev_dbg(&I801_dev->dev, "SMBus busy (%02x). "
				"Resetting... \n", temp);
			outb_p(temp, SMBHSTSTS);
			if (((temp = inb_p(SMBHSTSTS)) & errmask) != 0x00) {
				dev_err(&I801_dev->dev,
					"Reset failed! (%02x)\n", temp);
				result = -1;
                                goto END;
			}
			if (i != 1) {
				/* if die in middle of block transaction, fail */
				result = -1;
				goto END;
			}
		}

		if (i == 1)
			outb_p(inb(SMBHSTCNT) | I801_START, SMBHSTCNT);

		/* We will always wait for a fraction of a second! */
		timeout = 0;
		do {
			temp = inb_p(SMBHSTSTS);
			i801_do_pause(1);
		}
		    while ((!(temp & 0x80))
			   && (timeout++ < MAX_TIMEOUT));

		/* If the SMBus is still busy, we give up */
		if (timeout >= MAX_TIMEOUT) {
			result = -1;
			dev_dbg(&I801_dev->dev, "SMBus Timeout!\n");
		}

		if (temp & 0x10) {
			result = -1;
			dev_dbg(&I801_dev->dev,
				"Error: Failed bus transaction\n");
		} else if (temp & 0x08) {
			result = -1;
			dev_err(&I801_dev->dev, "Bus collision!\n");
		} else if (temp & 0x04) {
			result = -1;
			dev_dbg(&I801_dev->dev, "Error: no response!\n");
		}

		if (i == 1 && read_write == I2C_SMBUS_READ) {
			len = inb_p(SMBHSTDAT0);
			if (len < 1)
				len = 1;
			if (len > 32)
				len = 32;
			data->block[0] = len;
		}

		/* Retrieve/store value in SMBBLKDAT */
		if (read_write == I2C_SMBUS_READ)
			data->block[i] = inb_p(SMBBLKDAT);
		if (read_write == I2C_SMBUS_WRITE && i+1 <= len)
			outb_p(data->block[i+1], SMBBLKDAT);
		if ((temp & 0x9e) != 0x00)
			outb_p(temp, SMBHSTSTS);  /* signals SMBBLKDAT ready */

		if ((temp = (0x1e & inb_p(SMBHSTSTS))) != 0x00) {
			dev_dbg(&I801_dev->dev,
				"Bad status (%02x) at end of transaction\n",
				temp);
		}
		dev_dbg(&I801_dev->dev, "Block (post %d): CNT=%02x, CMD=%02x, "
			"ADD=%02x, DAT0=%02x, BLKDAT=%02x\n", i,
			inb_p(SMBHSTCNT), inb_p(SMBHSTCMD), inb_p(SMBHSTADD),
			inb_p(SMBHSTDAT0), inb_p(SMBBLKDAT));

		if (result < 0)
			goto END;
	}

#ifdef HAVE_PEC
	if(isich4 && command == I2C_SMBUS_BLOCK_DATA_PEC) {
		/* wait for INTR bit as advised by Intel */
		timeout = 0;
		do {
			temp = inb_p(SMBHSTSTS);
			i801_do_pause(1);
		} while ((!(temp & 0x02))
			   && (timeout++ < MAX_TIMEOUT));

		if (timeout >= MAX_TIMEOUT) {
			dev_dbg(&I801_dev->dev, "PEC Timeout!\n");
		}
		outb_p(temp, SMBHSTSTS); 
	}
#endif
	result = 0;
END:
	if (command == I2C_SMBUS_I2C_BLOCK_DATA) {
		/* restore saved configuration register value */
		pci_write_config_byte(I801_dev, SMBHSTCFG, hostc);
	}
	return result;
}

/* Return -1 on error. */
static s32 i801_access(struct i2c_adapter * adap, u16 addr,
		       unsigned short flags, char read_write, u8 command,
		       int size, union i2c_smbus_data * data)
{
	int hwpec = 0;
	int block = 0;
	int ret, xact = 0;

#ifdef HAVE_PEC
	if(isich4)
		hwpec = (flags & I2C_CLIENT_PEC) != 0;
#endif

	switch (size) {
	case I2C_SMBUS_QUICK:
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		xact = I801_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);
		xact = I801_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);
		xact = I801_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);
		}
		xact = I801_WORD_DATA;
		break;
	case I2C_SMBUS_BLOCK_DATA:
	case I2C_SMBUS_I2C_BLOCK_DATA:
#ifdef HAVE_PEC
	case I2C_SMBUS_BLOCK_DATA_PEC:
		if(hwpec && size == I2C_SMBUS_BLOCK_DATA)
			size = I2C_SMBUS_BLOCK_DATA_PEC;
#endif
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		outb_p(command, SMBHSTCMD);
		block = 1;
		break;
	case I2C_SMBUS_PROC_CALL:
	default:
		dev_err(&I801_dev->dev, "Unsupported transaction %d\n", size);
		return -1;
	}

#ifdef HAVE_PEC
	if(isich4 && hwpec) {
		if(size != I2C_SMBUS_QUICK &&
		   size != I2C_SMBUS_I2C_BLOCK_DATA)
			outb_p(1, SMBAUXCTL);	/* enable HW PEC */
	}
#endif
	if(block)
		ret = i801_block_transaction(data, read_write, size);
	else {
		outb_p(xact | ENABLE_INT9, SMBHSTCNT);
		ret = i801_transaction();
	}

#ifdef HAVE_PEC
	if(isich4 && hwpec) {
		if(size != I2C_SMBUS_QUICK &&
		   size != I2C_SMBUS_I2C_BLOCK_DATA)
			outb_p(0, SMBAUXCTL);
	}
#endif

	if(block)
		return ret;
	if(ret)
		return -1;
	if ((read_write == I2C_SMBUS_WRITE) || (xact == I801_QUICK))
		return 0;

	switch (xact & 0x7f) {
	case I801_BYTE:	/* Result put in SMBHSTDAT0 */
	case I801_BYTE_DATA:
		data->byte = inb_p(SMBHSTDAT0);
		break;
	case I801_WORD_DATA:
		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
		break;
	}
	return 0;
}


static u32 i801_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 | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK
#ifdef HAVE_PEC
	     | (isich4 ? I2C_FUNC_SMBUS_BLOCK_DATA_PEC |
	                 I2C_FUNC_SMBUS_HWPEC_CALC
	               : 0)
#endif
	    ;
}

static struct i2c_algorithm smbus_algorithm = {
	.name		= "Non-I2C SMBus adapter",
	.id		= I2C_ALGO_SMBUS,
	.smbus_xfer	= i801_access,
	.functionality	= i801_func,
};

static struct i2c_adapter i801_adapter = {
	.owner		= THIS_MODULE,
	.id		= I2C_ALGO_SMBUS | I2C_HW_SMBUS_I801,
	.algo		= &smbus_algorithm,
	.dev		= {
		.name	= "unset",
	},
};

static struct pci_device_id i801_ids[] __devinitdata = {
	{
		.vendor =	PCI_VENDOR_ID_INTEL,
		.device =	PCI_DEVICE_ID_INTEL_82801AA_3,
		.subvendor =	PCI_ANY_ID,
		.subdevice =	PCI_ANY_ID,
	},
	{
		.vendor =	PCI_VENDOR_ID_INTEL,
		.device =	PCI_DEVICE_ID_INTEL_82801AB_3,
		.subvendor =	PCI_ANY_ID,
		.subdevice =	PCI_ANY_ID,
	},
	{
		.vendor =	PCI_VENDOR_ID_INTEL,
		.device =	PCI_DEVICE_ID_INTEL_82801BA_2,
		.subvendor =	PCI_ANY_ID,
		.subdevice =	PCI_ANY_ID,
	},
	{
		.vendor =	PCI_VENDOR_ID_INTEL,
		.device =	PCI_DEVICE_ID_INTEL_82801CA_3,
		.subvendor =	PCI_ANY_ID,
		.subdevice =	PCI_ANY_ID,
	},
	{
		.vendor =	PCI_VENDOR_ID_INTEL,
		.device =	PCI_DEVICE_ID_INTEL_82801DB_3,
		.subvendor =	PCI_ANY_ID,
		.subdevice =	PCI_ANY_ID,
	},
	{ 0, }
};

static int __devinit i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
{

	if (i801_setup(dev)) {
		dev_warn(&dev->dev,
			"I801 not detected, module not inserted.\n");
		return -ENODEV;
	}

	/* set up the driverfs linkage to our parent device */
	i801_adapter.dev.parent = &dev->dev;

	snprintf(i801_adapter.dev.name, DEVICE_NAME_SIZE,
		"SMBus I801 adapter at %04x", i801_smba);
	return i2c_add_adapter(&i801_adapter);
}

static void __devexit i801_remove(struct pci_dev *dev)
{
	i2c_del_adapter(&i801_adapter);
}

static struct pci_driver i801_driver = {
	.name		= "i801 smbus",
	.id_table	= i801_ids,
	.probe		= i801_probe,
	.remove		= __devexit_p(i801_remove),
};

static int __init i2c_i801_init(void)
{
	printk(KERN_INFO "i2c-i801 version %s (%s)\n", I2C_VERSION, I2C_DATE);
	return pci_module_init(&i801_driver);
}

static void __exit i2c_i801_exit(void)
{
	pci_unregister_driver(&i801_driver);
	release_region(i801_smba, (isich4 ? 16 : 8));
}

MODULE_AUTHOR ("Frodo Looijaard <frodol@dds.nl>, "
		"Philip Edelbrock <phil@netroedge.com>, "
		"and Mark D. Studebaker <mdsxyz123@yahoo.com>");
MODULE_DESCRIPTION("I801 SMBus driver");
MODULE_LICENSE("GPL");

module_init(i2c_i801_init);
module_exit(i2c_i801_exit);
