smbus.c

// Copyright (c) 2011 Scott Mansell <phiren@gmail.com>
// Licensed under the MIT license
// Refer to the included LICENCE file.

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/types.h>


uint16_t eepromRead(uint8_t addr) {
	debugf("Eeprom read 0x%02x\n", addr);
	return 0;
}

uint16_t picRead(uint8_t cmd) {
	switch(cmd) {
	case 0x4: // av pack
		return 0x7; // disconnected
	// Challange. These are meant to be random, but the what the bios doesn't know can't hurt it.
	case 0x1c:
		return 0xde;
	case 0x1d:
		return 0xad;
	case 0x1e:
		return 0xbe;
	case 0x1f:
		return 0xef;
	default:
		debugf("PIC: unimplemented read: 0x%02x\n", cmd);
		return 0;
	}
}

void picWrite(uint8_t cmd, uint16_t data) {
	switch(cmd) {
	case 0x20:
		return;
	case 0x21:
		debugf("PIC: Loader is authenticated, we won't reset the cpu ;D\n");
		return;
	default:
		debugf("PIC: unimplemented write: 0x%02x\n", cmd);
	}
}

unsigned char address;
unsigned char command;
unsigned short data;

void smbusIO(uint16_t port, uint8_t direction, uint8_t size, uint8_t *p) {
	//printf("smbus: ");
	switch(direction) {
	case 1: // out
		switch(port) {
		case 0xc004:
			address = *p;
			break;
		case 0xc006:
			if(size == 1) data = *p;
			else data = *(uint16_t*)p;
			break;
		case 0xc008:
			command = *p;
			break;
		case 0xc000:
			break;//we don't care if the software writes to the status port
		case 0xc002:
			switch(address) {
			case 0x54 << 1 | 1:
				data = eepromRead(command);
				break;
			case 0x10 << 1 | 1:
				data = picRead(command);
				break;
			case 0x10 << 1 | 0:
				picWrite(command, data);
				break;
			default:
				if((address & 1) == 0) { // Write
					if(*p == 0xa) {
						debugf("SMBus: Write %02x:%02x = 0x%02x\n", address>>1, command, data);
					}
					else if(*p == 0xb) {
						debugf("SMBus: Write %02x:%02x = 0x%04x\n", address>>1, command, data);
					} else printf("SMBus: Unsupport opperation");
				} else {
					debugf("SMBus: Read %02x:%02x\n", address>>1, command);
				}
			} 
			break;
		default:
			debugf("smbus: unhandled out port 0x%04x\n", port);
		}
		break;
	case 0: // in
		switch(port) {
		case 0xc000:
			*p = 0x10; // Cycle complete
			break;
		case 0xc006:
			if(size == 1) *p = (uint8_t) data;
			else *(uint16_t*)p = data;
			break;
		default:
			debugf("smbus: unhandled port in 0x%04x\n", port);
		}
	}
}