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/*
* *AT24C* series I2C EEPROM
*
* Copyright (c) 2015 Michael Davidsaver
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the LICENSE file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "hw/i2c/i2c.h"
#include "hw/qdev-properties.h"
#include "hw/qdev-properties-system.h"
#include "sysemu/block-backend.h"
#include "qom/object.h"
/* #define DEBUG_AT24C */
#ifdef DEBUG_AT24C
#define DPRINTK(FMT, ...) printf(TYPE_AT24C_EE " : " FMT, ## __VA_ARGS__)
#else
#define DPRINTK(FMT, ...) do {} while (0)
#endif
#define ERR(FMT, ...) fprintf(stderr, TYPE_AT24C_EE " : " FMT, \
## __VA_ARGS__)
#define TYPE_AT24C_EE "at24c-eeprom"
typedef struct EEPROMState EEPROMState;
DECLARE_INSTANCE_CHECKER(EEPROMState, AT24C_EE,
TYPE_AT24C_EE)
struct EEPROMState {
I2CSlave parent_obj;
/* address counter */
uint16_t cur;
/* total size in bytes */
uint32_t rsize;
bool writable;
/* cells changed since last START? */
bool changed;
/* during WRITE, # of address bytes transfered */
uint8_t haveaddr;
uint8_t *mem;
BlockBackend *blk;
};
static
int at24c_eeprom_event(I2CSlave *s, enum i2c_event event)
{
EEPROMState *ee = AT24C_EE(s);
switch (event) {
case I2C_START_SEND:
case I2C_FINISH:
ee->haveaddr = 0;
/* fallthrough */
case I2C_START_RECV:
DPRINTK("clear\n");
if (ee->blk && ee->changed) {
int ret = blk_pwrite(ee->blk, 0, ee->rsize, ee->mem, 0);
if (ret < 0) {
ERR(TYPE_AT24C_EE
" : failed to write backing file\n");
}
DPRINTK("Wrote to backing file\n");
}
ee->changed = false;
break;
case I2C_NACK:
break;
default:
return -1;
}
return 0;
}
static
uint8_t at24c_eeprom_recv(I2CSlave *s)
{
EEPROMState *ee = AT24C_EE(s);
uint8_t ret;
if (ee->haveaddr == 1) {
return 0xff;
}
ret = ee->mem[ee->cur];
ee->cur = (ee->cur + 1u) % ee->rsize;
DPRINTK("Recv %02x %c\n", ret, ret);
return ret;
}
static
int at24c_eeprom_send(I2CSlave *s, uint8_t data)
{
EEPROMState *ee = AT24C_EE(s);
if (ee->haveaddr < 2) {
ee->cur <<= 8;
ee->cur |= data;
ee->haveaddr++;
if (ee->haveaddr == 2) {
ee->cur %= ee->rsize;
DPRINTK("Set pointer %04x\n", ee->cur);
}
} else {
if (ee->writable) {
DPRINTK("Send %02x\n", data);
ee->mem[ee->cur] = data;
ee->changed = true;
} else {
DPRINTK("Send error %02x read-only\n", data);
}
ee->cur = (ee->cur + 1u) % ee->rsize;
}
return 0;
}
static void at24c_eeprom_realize(DeviceState *dev, Error **errp)
{
EEPROMState *ee = AT24C_EE(dev);
if (ee->blk) {
int64_t len = blk_getlength(ee->blk);
if (len != ee->rsize) {
error_setg(errp, "%s: Backing file size %" PRId64 " != %u",
TYPE_AT24C_EE, len, ee->rsize);
return;
}
if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE,
BLK_PERM_ALL, &error_fatal) < 0)
{
error_setg(errp, "%s: Backing file incorrect permission",
TYPE_AT24C_EE);
return;
}
}
ee->mem = g_malloc0(ee->rsize);
}
static
void at24c_eeprom_reset(DeviceState *state)
{
EEPROMState *ee = AT24C_EE(state);
ee->changed = false;
ee->cur = 0;
ee->haveaddr = 0;
memset(ee->mem, 0, ee->rsize);
if (ee->blk) {
int ret = blk_pread(ee->blk, 0, ee->rsize, ee->mem, 0);
if (ret < 0) {
ERR(TYPE_AT24C_EE
" : Failed initial sync with backing file\n");
}
DPRINTK("Reset read backing file\n");
}
}
static Property at24c_eeprom_props[] = {
DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
DEFINE_PROP_END_OF_LIST()
};
static
void at24c_eeprom_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
dc->realize = &at24c_eeprom_realize;
k->event = &at24c_eeprom_event;
k->recv = &at24c_eeprom_recv;
k->send = &at24c_eeprom_send;
device_class_set_props(dc, at24c_eeprom_props);
dc->reset = at24c_eeprom_reset;
}
static
const TypeInfo at24c_eeprom_type = {
.name = TYPE_AT24C_EE,
.parent = TYPE_I2C_SLAVE,
.instance_size = sizeof(EEPROMState),
.class_size = sizeof(I2CSlaveClass),
.class_init = at24c_eeprom_class_init,
};
static void at24c_eeprom_register(void)
{
type_register_static(&at24c_eeprom_type);
}
type_init(at24c_eeprom_register)
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