I2C overhaul part 2

src/device/i2c_eeprom.c

@@ -0,0 +1,102 @@
+/*
+ * 86Box	A hypervisor and IBM PC system emulator that specializes in
+ *		running old operating systems and software designed for IBM
+ *		PC systems and compatibles from 1981 through fairly recent
+ *		system designs based on the PCI bus.
+ *
+ *		This file is part of the 86Box distribution.
+ *
+ *		Emulation of the AT24Cxx series of I2C EEPROMs.
+ *
+ *
+ *
+ * Authors:	RichardG, <richardg867@gmail.com>
+ *
+ *		Copyright 2020 RichardG.
+ */
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#define HAVE_STDARG_H
+#include <wchar.h>
+#include <86box/86box.h>
+#include <86box/i2c.h>
+
+
+typedef struct {
+    void	*i2c;
+    uint8_t	addr;
+    uint8_t	*data;
+    uint8_t	writable;
+
+    uint16_t	addr_mask;
+    uint8_t	addr_register;
+    uint8_t	i2c_state;
+} i2c_eeprom_t;
+
+
+void
+i2c_eeprom_start(void *bus, uint8_t addr, void *priv)
+{
+    i2c_eeprom_t *dev = (i2c_eeprom_t *) priv;
+
+    dev->i2c_state = 0;
+}
+
+
+uint8_t
+i2c_eeprom_read(void *bus, uint8_t addr, void *priv)
+{
+    i2c_eeprom_t *dev = (i2c_eeprom_t *) priv;
+
+    return dev->data[((addr << 8) | dev->addr_register++) & dev->addr_mask];
+}
+
+
+uint8_t
+i2c_eeprom_write(void *bus, uint8_t addr, uint8_t data, void *priv)
+{
+    i2c_eeprom_t *dev = (i2c_eeprom_t *) priv;
+
+    if (dev->i2c_state == 0) {
+	dev->i2c_state = 1;
+	dev->addr_register = data;
+    } else if (dev->writable)
+	dev->data[((addr << 8) | dev->addr_register++) & dev->addr_mask] = data;
+    else
+	return 0;
+
+    return 1;
+}
+
+
+void *
+i2c_eeprom_init(void *i2c, uint8_t addr, uint8_t *data, uint16_t size, uint8_t writable)
+{
+    i2c_eeprom_t *dev = (i2c_eeprom_t *) malloc(sizeof(i2c_eeprom_t));
+    memset(dev, 0, sizeof(i2c_eeprom_t));
+
+    dev->i2c = i2c;
+    dev->addr = addr;
+    dev->data = data;
+    dev->writable = writable;
+
+    dev->addr_mask = size - 1;
+
+    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);
+
+    return dev;
+}
+
+
+void
+i2c_eeprom_close(void *dev_handle)
+{
+    i2c_eeprom_t *dev = (i2c_eeprom_t *) dev_handle;
+
+    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);
+
+    free(dev);
+}