162 lines
4.1 KiB
C
162 lines
4.1 KiB
C
/*
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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 24Cxx 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, *data, writable;
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uint32_t addr_mask, addr_register;
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uint8_t addr_len, addr_pos;
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} i2c_eeprom_t;
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#define ENABLE_I2C_EEPROM_LOG 1
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#ifdef ENABLE_I2C_EEPROM_LOG
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int i2c_eeprom_do_log = ENABLE_I2C_EEPROM_LOG;
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static void
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i2c_eeprom_log(const char *fmt, ...)
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{
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va_list ap;
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if (i2c_eeprom_do_log) {
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va_start(ap, fmt);
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pclog_ex(fmt, ap);
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va_end(ap);
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}
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}
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#else
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#define i2c_eeprom_log(fmt, ...)
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#endif
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static uint8_t
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i2c_eeprom_start(void *bus, uint8_t addr, uint8_t read, void *priv)
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{
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i2c_eeprom_t *dev = (i2c_eeprom_t *) priv;
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i2c_eeprom_log("I2C EEPROM %s %02X: start()\n", i2c_getbusname(dev->i2c), dev->addr);
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if (!read) {
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dev->addr_pos = 0;
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dev->addr_register = (addr << dev->addr_len) & dev->addr_mask;
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}
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return 1;
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}
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static 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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uint8_t ret = dev->data[dev->addr_register];
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i2c_eeprom_log("I2C EEPROM %s %02X: read(%06X) = %02X\n", i2c_getbusname(dev->i2c), dev->addr, dev->addr_register, ret);
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dev->addr_register++;
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dev->addr_register &= dev->addr_mask; /* roll-over */
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return ret;
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}
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static 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->addr_pos < dev->addr_len) {
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dev->addr_register <<= 8;
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dev->addr_register |= data;
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dev->addr_register &= (1 << dev->addr_len) - 1;
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dev->addr_register |= addr << dev->addr_len;
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dev->addr_register &= dev->addr_mask;
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i2c_eeprom_log("I2C EEPROM %s %02X: write(address, %06X)\n", i2c_getbusname(dev->i2c), dev->addr, dev->addr_register);
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dev->addr_pos += 8;
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} else {
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i2c_eeprom_log("I2C EEPROM %s %02X: write(%06X, %02X) = %d\n", i2c_getbusname(dev->i2c), dev->addr, dev->addr_register, data, !!dev->writable);
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if (dev->writable)
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dev->data[dev->addr_register] = data;
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dev->addr_register++;
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dev->addr_register &= dev->addr_mask; /* roll-over */
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return dev->writable;
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}
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return 1;
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}
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uint8_t
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log2i(uint32_t i)
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{
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uint8_t ret = 0;
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while ((i >>= 1))
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ret++;
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return ret;
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}
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void *
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i2c_eeprom_init(void *i2c, uint8_t addr, uint8_t *data, uint32_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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/* Round size up to the next power of 2. */
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uint32_t pow_size = 1 << log2i(size);
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if (pow_size < size)
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size = pow_size << 1;
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size &= 0x7fffff; /* address space limit of 8 MB = 7 bits from I2C address + 16 bits */
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i2c_eeprom_log("I2C EEPROM %s %02X: init(%d, %d)\n", i2c_getbusname(i2c), addr, size, writable);
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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_len = (size >= 4096) ? 16 : 8; /* use 16-bit addresses on 24C32 and above */
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dev->addr_mask = size - 1;
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i2c_sethandler(dev->i2c, dev->addr & ~(dev->addr_mask >> dev->addr_len), (dev->addr_mask >> dev->addr_len) + 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_eeprom_log("I2C EEPROM %s %02X: close()\n", i2c_getbusname(dev->i2c), dev->addr);
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i2c_removehandler(dev->i2c, dev->addr & ~(dev->addr_mask >> dev->addr_len), (dev->addr_mask >> dev->addr_len) + 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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