/*
 * This file is part of the LinuxBIOS project.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include "i82801db_smbus.h"

#define SMBUS_IO_BASE 0x0f00

static void enable_smbus(void)
{
	device_t dev;
	dev = pci_locate_device(PCI_ID(0x8086, 0x24d3), 0);
	if (dev == PCI_DEV_INVALID) {
		die("SMBUS controller not found\r\n");
	}
	print_spew("SMBus controller enabled\r\n");
	
	pci_write_config32(dev, 0x20, SMBUS_IO_BASE | 1);
	/* Set smbus enable */
	pci_write_config8(dev, 0x40, 1);
	/* Set smbus iospace enable */
	pci_write_config8(dev, 0x4, 1);
	/* SMBALERT_DIS */
	pci_write_config8(dev, 0x11, 4);
	
	/* Disable interrupt generation */
	outb(0, SMBUS_IO_BASE + SMBHSTCTL);

	/* clear any lingering errors, so the transaction will run */
	outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT);

#if 0	// It's unlikely that half the southbridge suddenly vanishes?
	dev = pci_locate_device(PCI_ID(0x8086, 0x24d0), 0);
	if (dev == PCI_DEV_INVALID) {
		die("ISA bridge not found\r\n");
	}
#endif
}

static int smbus_read_byte(unsigned device, unsigned address)
{
	return do_smbus_read_byte(SMBUS_IO_BASE, device, address);
}

static void smbus_write_byte(unsigned device, unsigned address, unsigned char val)
{
	if (smbus_wait_until_ready(SMBUS_IO_BASE) < 0) {
		return;
	}
	
	print_debug("Unimplemented smbus_write_byte() called.\r\n");

#if 0
	/* setup transaction */
	/* disable interrupts */
	outw(inw(SMBUS_IO_BASE + SMBGCTL) & ~((1<<10)|(1<<9)|(1<<8)|(1<<4)),
			SMBUS_IO_BASE + SMBGCTL);
	/* set the device I'm talking too */
	outw(((device & 0x7f) << 1) | 1, SMBUS_IO_BASE + SMBHSTADDR);
	outb(address & 0xFF, SMBUS_IO_BASE + SMBHSTCMD);
	/* set up for a byte data write */ /* FIXME */
	outw((inw(SMBUS_IO_BASE + SMBGCTL) & ~7) | (0x1), SMBUS_IO_BASE + SMBGCTL);
	/* clear any lingering errors, so the transaction will run */
	/* Do I need to write the bits to a 1 to clear an error? */
	outw(inw(SMBUS_IO_BASE + SMBGSTATUS), SMBUS_IO_BASE + SMBGSTATUS);

	/* clear the data word...*/
	outw(val, SMBUS_IO_BASE + SMBHSTDAT);

	/* start the command */
	outw((inw(SMBUS_IO_BASE + SMBGCTL) | (1 << 3)), SMBUS_IO_BASE + SMBGCTL);

	/* poll for transaction completion */
	smbus_wait_until_done(SMBUS_IO_BASE);
#endif	
	return;
}

static int smbus_write_block(unsigned device, unsigned length, unsigned cmd, 
		 unsigned data1, unsigned data2)
{
	unsigned char global_control_register;
	unsigned char global_status_register;
	unsigned char byte;
	unsigned char stat;
	int i;

	/* chear the PM timeout flags, SECOND_TO_STS */
	outw(inw(0x0400 + 0x66), 0x0400 + 0x66);
	
	if (smbus_wait_until_ready(SMBUS_IO_BASE) < 0) {
		return -2;
	}
	
	/* setup transaction */
	/* Obtain ownership */
	outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT);
	for(stat=0;(stat&0x40)==0;) {
	stat = inb(SMBUS_IO_BASE + SMBHSTSTAT);
	}
	/* clear the done bit */
	outb(0x80, SMBUS_IO_BASE + SMBHSTSTAT);
	/* disable interrupts */
	outb(inb(SMBUS_IO_BASE + SMBHSTCTL) & (~1), SMBUS_IO_BASE + SMBHSTCTL);
	
	/* set the device I'm talking too */
	outb(((device & 0x7f) << 1), SMBUS_IO_BASE + SMBXMITADD);
	
	/* set the command address */
	outb(cmd & 0xFF, SMBUS_IO_BASE + SMBHSTCMD);
	
	/* set the block length */
	outb(length & 0xFF, SMBUS_IO_BASE + SMBHSTDAT0);
	
	/* try sending out the first byte of data here */
	byte=(data1>>(0))&0x0ff;
	outb(byte,SMBUS_IO_BASE + SMBBLKDAT);
	/* issue a block write command */
	outb((inb(SMBUS_IO_BASE + SMBHSTCTL) & 0xE3) | (0x5 << 2) | 0x40, 
			SMBUS_IO_BASE + SMBHSTCTL);

	for(i=0;i<length;i++) {
		
		/* poll for transaction completion */
		if (smbus_wait_until_blk_done(SMBUS_IO_BASE) < 0) {
			return -3;
		}
		
		/* load the next byte */
		if(i>3)
			byte=(data2>>(i%4))&0x0ff;
		else
			byte=(data1>>(i))&0x0ff;
		outb(byte,SMBUS_IO_BASE + SMBBLKDAT);
		
		/* clear the done bit */
		outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), 
				SMBUS_IO_BASE + SMBHSTSTAT);
	}

	print_debug("SMBUS Block complete\r\n");
	return 0;
}