/*
 * SMBus 2.0 driver for AMD-8111 IO-Hub.
 *
 * Copyright (c) 2002 Vojtech Pavlik
 *
 * 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 version 2.
 */

#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/init.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include "version.h"

#ifndef I2C_HW_SMBUS_AMD8111
#error Your i2c is too old - i2c-2.7.0 or greater required!
#endif

MODULE_LICENSE("GPL");
MODULE_AUTHOR ("Vojtech Pavlik <vojtech@suse.cz>");
MODULE_DESCRIPTION("AMD8111 SMBus 2.0 driver");

struct amd_smbus {
	struct pci_dev *dev;
	struct i2c_adapter adapter;
	int base;
	int size;
};

/*
 * AMD PCI control registers definitions.
 */

#define AMD_PCI_MISC	0x48

#define AMD_PCI_MISC_SCI	0x04	/* deliver SCI */
#define AMD_PCI_MISC_INT	0x02	/* deliver PCI IRQ */
#define AMD_PCI_MISC_SPEEDUP	0x01	/* 16x clock speedup */

/*
 * ACPI 2.0 chapter 13 PCI interface definitions.
 */

#define AMD_EC_DATA	0x00	/* data register */
#define AMD_EC_SC	0x04	/* status of controller */
#define AMD_EC_CMD	0x04	/* command register */
#define AMD_EC_ICR	0x08	/* interrupt control register */

#define AMD_EC_SC_SMI	0x04	/* smi event pending */
#define AMD_EC_SC_SCI	0x02	/* sci event pending */
#define AMD_EC_SC_BURST	0x01	/* burst mode enabled */
#define AMD_EC_SC_CMD	0x08	/* byte in data reg is command */
#define AMD_EC_SC_IBF	0x02	/* data ready for embedded controller */
#define AMD_EC_SC_OBF	0x01	/* data ready for host */

#define AMD_EC_CMD_RD	0x80	/* read EC */
#define AMD_EC_CMD_WR	0x81	/* write EC */
#define AMD_EC_CMD_BE	0x82	/* enable burst mode */
#define AMD_EC_CMD_BD	0x83	/* disable burst mode */
#define AMD_EC_CMD_QR	0x84	/* query EC */

/*
 * ACPI 2.0 chapter 13 access of registers of the EC
 */

unsigned int amd_ec_wait_write(struct amd_smbus *smbus)
{
	int timeout = 500;

	while (timeout-- && (inb(smbus->base + AMD_EC_SC) & AMD_EC_SC_IBF))
		udelay(1);

	if (!timeout) {
		printk(KERN_WARNING "i2c-amd811.c: Timeout while waiting for IBF to clear\n");
		return -1;
	}

	return 0;
}

unsigned int amd_ec_wait_read(struct amd_smbus *smbus)
{
	int timeout = 500;

	while (timeout-- && (~inb(smbus->base + AMD_EC_SC) & AMD_EC_SC_OBF))
		udelay(1);

	if (!timeout) {
		printk(KERN_WARNING "i2c-amd8111.c: Timeout while waiting for OBF to set\n");
		return -1;
	}

	return 0;
}

unsigned int amd_ec_read(struct amd_smbus *smbus, unsigned char address, unsigned char *data)
{
	if (amd_ec_wait_write(smbus))
		return -1;
	outb(AMD_EC_CMD_RD, smbus->base + AMD_EC_CMD);

	if (amd_ec_wait_write(smbus))
		return -1;
	outb(address, smbus->base + AMD_EC_DATA);

	if (amd_ec_wait_read(smbus))
		return -1;
	*data = inb(smbus->base + AMD_EC_DATA);

	return 0;
}

unsigned int amd_ec_write(struct amd_smbus *smbus, unsigned char address, unsigned char data)
{
	if (amd_ec_wait_write(smbus))
		return -1;
	outb(AMD_EC_CMD_WR, smbus->base + AMD_EC_CMD);

	if (amd_ec_wait_write(smbus))
		return -1;
	outb(address, smbus->base + AMD_EC_DATA);

	if (amd_ec_wait_write(smbus))
		return -1;
	outb(data, smbus->base + AMD_EC_DATA);

	return 0;
}

/*
 * ACPI 2.0 chapter 13 SMBus 2.0 EC register model
 */

#define AMD_SMB_PRTCL	0x00	/* protocol, PEC */
#define AMD_SMB_STS	0x01	/* status */
#define AMD_SMB_ADDR	0x02	/* address */
#define AMD_SMB_CMD	0x03	/* command */
#define AMD_SMB_DATA	0x04	/* 32 data registers */
#define AMD_SMB_BCNT	0x24	/* number of data bytes */
#define AMD_SMB_ALRM_A	0x25	/* alarm address */
#define AMD_SMB_ALRM_D	0x26	/* 2 bytes alarm data */

#define AMD_SMB_STS_DONE	0x80
#define AMD_SMB_STS_ALRM	0x40
#define AMD_SMB_STS_RES		0x20
#define AMD_SMB_STS_STATUS	0x1f

#define AMD_SMB_STATUS_OK	0x00
#define AMD_SMB_STATUS_FAIL	0x07
#define AMD_SMB_STATUS_DNAK	0x10
#define AMD_SMB_STATUS_DERR	0x11
#define AMD_SMB_STATUS_CMD_DENY	0x12
#define AMD_SMB_STATUS_UNKNOWN	0x13
#define AMD_SMB_STATUS_ACC_DENY	0x17
#define AMD_SMB_STATUS_TIMEOUT	0x18
#define AMD_SMB_STATUS_NOTSUP	0x19
#define AMD_SMB_STATUS_BUSY	0x1A
#define AMD_SMB_STATUS_PEC	0x1F

#define AMD_SMB_PRTCL_QUICK		0x02
#define AMD_SMB_PRTCL_BYTE		0x04
#define AMD_SMB_PRTCL_BYTE_DATA		0x06
#define AMD_SMB_PRTCL_WORD_DATA		0x08
#define AMD_SMB_PRTCL_BLOCK_DATA	0x0a
#define AMD_SMB_PRTCL_PROC_CALL		0x0c
#define AMD_SMB_PRTCL_BLOCK_PROC_CALL	0x0d
#define AMD_SMB_PRTCL_I2C_BLOCK_DATA	0x4a
#define AMD_SMB_PRTCL_PEC		0x80


s32 amd8111_access(struct i2c_adapter * adap, u16 addr, unsigned short flags,
		char read_write, u8 command, int size, union i2c_smbus_data * data)
{
	struct amd_smbus *smbus = adap->algo_data;
	unsigned char protocol = read_write;	/* 1 = read, 0 = write */
	unsigned char temp[2];
	int i, timeout = 5000;

	switch (size) {

		case I2C_SMBUS_QUICK:
			protocol |= AMD_SMB_PRTCL_QUICK;
			break;

		case I2C_SMBUS_BYTE:
			if (!read_write)
				amd_ec_write(smbus, AMD_SMB_DATA, data->byte);
			protocol |= AMD_SMB_PRTCL_BYTE;
			break;

		case I2C_SMBUS_BYTE_DATA:
			amd_ec_write(smbus, AMD_SMB_CMD, command);
			if (!read_write)
				amd_ec_write(smbus, AMD_SMB_DATA, data->byte);
			protocol |= AMD_SMB_PRTCL_BYTE_DATA;
			break;

		case I2C_SMBUS_WORD_DATA:
			amd_ec_write(smbus, AMD_SMB_CMD, command);
			if (!read_write) {
				amd_ec_write(smbus, AMD_SMB_DATA, data->byte);
				amd_ec_write(smbus, AMD_SMB_DATA + 1, data->byte >> 8);
			}
			protocol |= AMD_SMB_PRTCL_WORD_DATA;
			break;

		case I2C_SMBUS_BLOCK_DATA:
		case I2C_SMBUS_BLOCK_DATA_PEC:
		case I2C_SMBUS_I2C_BLOCK_DATA:
			amd_ec_write(smbus, AMD_SMB_CMD, command);
			if (!read_write)
				for (i = 0; i < data->block[0]; i++)
					amd_ec_write(smbus, AMD_SMB_DATA + i, data->block[i + 1]);
			switch (size) {
				case I2C_SMBUS_BLOCK_DATA:
					protocol |= AMD_SMB_PRTCL_BLOCK_DATA;
					break;
				case I2C_SMBUS_BLOCK_DATA_PEC:
					protocol |= AMD_SMB_PRTCL_BLOCK_DATA | AMD_SMB_PRTCL_PEC;
					break;
				case I2C_SMBUS_I2C_BLOCK_DATA:
					protocol |= AMD_SMB_PRTCL_I2C_BLOCK_DATA;
					break;
			}
			break;

		case I2C_SMBUS_PROC_CALL: /* We don't support proc_call yet */
		default:
			printk(KERN_WARNING "i2c-amd8111.c: Unsupported transaction %d\n", size);
			return -1;
	}

	amd_ec_write(smbus, AMD_SMB_ADDR, addr << 1);
	amd_ec_write(smbus, AMD_SMB_PRTCL, protocol);

	amd_ec_read(smbus, AMD_SMB_STS, temp + 0);

	while (timeout && ~temp[0] & AMD_SMB_STS_DONE) {
		amd_ec_read(smbus, AMD_SMB_STS, temp + 0);
		udelay(10);
		timeout--;
	}

	if (!timeout)
		return -1;

	if (~temp[0] & AMD_SMB_STS_DONE) {
		printk(KERN_WARNING "i2c-amd8111.c: Transaction completed with error %#x\n", temp[0]);
		return -1;
	}

	if (!read_write) /* We're done, no values to return; */
		return 0;

	switch (size) {

		case I2C_SMBUS_BYTE:
		case I2C_SMBUS_BYTE_DATA:
			amd_ec_read(smbus, AMD_SMB_DATA, &data->byte);
			break;

		case I2C_SMBUS_WORD_DATA:
			amd_ec_read(smbus, AMD_SMB_DATA, temp + 0);
			amd_ec_read(smbus, AMD_SMB_DATA + 1, temp + 1);
			data->word = (temp[1] << 8) | temp[0];
			break;

		case I2C_SMBUS_BLOCK_DATA:
		case I2C_SMBUS_BLOCK_DATA_PEC:
		case I2C_SMBUS_I2C_BLOCK_DATA:
			for (i = 0; i < data->block[0]; i++)
				amd_ec_read(smbus, AMD_SMB_DATA + i, data->block + i + 1);
			break;
	}

	return 0;
}

void amd8111_inc(struct i2c_adapter *adapter)
{
	MOD_INC_USE_COUNT;
}

void amd8111_dec(struct i2c_adapter *adapter)
{
	MOD_DEC_USE_COUNT;
}

u32 amd8111_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 |
	    I2C_FUNC_SMBUS_BLOCK_DATA_PEC | I2C_FUNC_SMBUS_HWPEC_CALC;
}

static struct i2c_algorithm smbus_algorithm = {
	.name = "Non-I2C SMBus 2.0 adapter",
	.id = I2C_ALGO_SMBUS,
	.smbus_xfer = amd8111_access,
	.functionality = amd8111_func,
};

static int __devinit amd8111_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
	struct amd_smbus *smbus;

	if (~pci_resource_flags(dev, 0) & IORESOURCE_IO)
		return -1;

	if (!(smbus = kmalloc(sizeof(struct amd_smbus), GFP_KERNEL)))
		return -1;
	memset(smbus, 0, sizeof(struct amd_smbus));

	pci_set_drvdata(dev, smbus);
	smbus->dev = dev;
	smbus->base = pci_resource_start(dev, 0);
	smbus->size = pci_resource_len(dev, 0);

	if (!request_region(smbus->base, smbus->size, "amd81111 SMBus 2.0")) {
		kfree(smbus);
		return -1;
	}

	sprintf(smbus->adapter.name, "SMBus2 AMD8111 adapter at %04x", smbus->base);
	smbus->adapter.id = I2C_ALGO_SMBUS | I2C_HW_SMBUS_AMD8111;
	smbus->adapter.algo = &smbus_algorithm;
	smbus->adapter.algo_data = smbus;
	smbus->adapter.inc_use = amd8111_inc;
	smbus->adapter.dec_use = amd8111_dec;

	pci_write_config_dword(dev, AMD_PCI_MISC, 0);

	if (i2c_add_adapter(&smbus->adapter)) {
		printk(KERN_WARNING "i2c-amd8111.c: Failed to register adapter.\n");
		release_region(smbus->base, smbus->size);
		kfree(smbus);
		return -1;
	}

	printk(KERN_INFO "i2c-amd8111.c: AMD8111 SMBus 2.0 adapter at pci%s\n", dev->slot_name);
	return 0;
}

static void __devexit amd8111_remove(struct pci_dev *dev)
{
	struct amd_smbus *smbus = pci_get_drvdata(dev);
	if (i2c_del_adapter(&smbus->adapter)) {
		printk(KERN_WARNING "i2c-amd81111.c: Failed to unregister adapter.\n");
		return;
	}
	release_region(smbus->base, smbus->size);
	kfree(smbus);
}

static struct pci_device_id amd8111_id_table[] __devinitdata =
{{ 0x1022, 0x746a, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
 { 0 }};

static struct pci_driver amd8111_driver = {
	.name = "amd8111 smbus 2.0",
	.id_table = amd8111_id_table,
	.probe = amd8111_probe,
	.remove = amd8111_remove,
};

int __init amd8111_init(void)
{
	return pci_module_init(&amd8111_driver);
}

void __exit amd8111_exit(void)
{
	pci_unregister_driver(&amd8111_driver);
}

module_init(amd8111_init);
module_exit(amd8111_exit);