103 lines
2.2 KiB
C
103 lines
2.2 KiB
C
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/*
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* 86Box A hypervisor and IBM PC system emulator that specializes in
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* running old operating systems and software designed for IBM
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* PC systems and compatibles from 1981 through fairly recent
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* system designs based on the PCI bus.
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*
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* This file is part of the 86Box distribution.
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*
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* Emulation of the AT24Cxx series of I2C EEPROMs.
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*
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*
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*
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* Authors: RichardG, <richardg867@gmail.com>
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*
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* Copyright 2020 RichardG.
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*/
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#define HAVE_STDARG_H
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#include <wchar.h>
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#include <86box/86box.h>
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#include <86box/i2c.h>
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typedef struct {
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void *i2c;
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uint8_t addr;
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uint8_t *data;
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uint8_t writable;
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uint16_t addr_mask;
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uint8_t addr_register;
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uint8_t i2c_state;
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} i2c_eeprom_t;
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void
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i2c_eeprom_start(void *bus, uint8_t addr, void *priv)
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{
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i2c_eeprom_t *dev = (i2c_eeprom_t *) priv;
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dev->i2c_state = 0;
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}
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uint8_t
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i2c_eeprom_read(void *bus, uint8_t addr, void *priv)
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{
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i2c_eeprom_t *dev = (i2c_eeprom_t *) priv;
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return dev->data[((addr << 8) | dev->addr_register++) & dev->addr_mask];
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}
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uint8_t
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i2c_eeprom_write(void *bus, uint8_t addr, uint8_t data, void *priv)
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{
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i2c_eeprom_t *dev = (i2c_eeprom_t *) priv;
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if (dev->i2c_state == 0) {
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dev->i2c_state = 1;
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dev->addr_register = data;
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} else if (dev->writable)
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dev->data[((addr << 8) | dev->addr_register++) & dev->addr_mask] = data;
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else
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return 0;
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return 1;
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}
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void *
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i2c_eeprom_init(void *i2c, uint8_t addr, uint8_t *data, uint16_t size, uint8_t writable)
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{
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i2c_eeprom_t *dev = (i2c_eeprom_t *) malloc(sizeof(i2c_eeprom_t));
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memset(dev, 0, sizeof(i2c_eeprom_t));
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dev->i2c = i2c;
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dev->addr = addr;
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dev->data = data;
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dev->writable = writable;
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dev->addr_mask = size - 1;
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i2c_sethandler(i2c, dev->addr & ~(dev->addr_mask >> 8), (dev->addr_mask >> 8) + 1, i2c_eeprom_start, i2c_eeprom_read, i2c_eeprom_write, NULL, dev);
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return dev;
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}
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void
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i2c_eeprom_close(void *dev_handle)
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{
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i2c_eeprom_t *dev = (i2c_eeprom_t *) dev_handle;
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i2c_removehandler(dev->i2c, dev->addr & ~(dev->addr_mask >> 8), (dev->addr_mask >> 8) + 1, i2c_eeprom_start, i2c_eeprom_read, i2c_eeprom_write, NULL, dev);
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free(dev);
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}
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