[2/2] Add AT24Cxx I2C EEPROM device model

diff --git a/hw/Makefile.objs b/hw/Makefile.objs
index ea46f81..0c64712 100644
--- a/hw/Makefile.objs
+++ b/hw/Makefile.objs
@@ -170,7 +170,7 @@  common-obj-$(CONFIG_SSD0323) += ssd0323.o
 common-obj-$(CONFIG_ADS7846) += ads7846.o
 common-obj-$(CONFIG_MAX111X) += max111x.o
 common-obj-$(CONFIG_DS1338) += ds1338.o
-common-obj-y += i2c.o smbus.o smbus_eeprom.o
+common-obj-y += i2c.o smbus.o smbus_eeprom.o at24.o
 common-obj-y += eeprom93xx.o
 common-obj-y += scsi-disk.o cdrom.o hd-geometry.o block-common.o
 common-obj-y += scsi-generic.o scsi-bus.o
diff --git a/hw/at24.c b/hw/at24.c
new file mode 100644
index 0000000..e34f2da
--- /dev/null
+++ b/hw/at24.c
@@ -0,0 +1,363 @@ 
+/*
+ * AT24Cxx EEPROM emulation
+ *
+ * Copyright (c) 2012 Siemens AG
+ * Author: Jan Kiszka
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "hw.h"
+#include "i2c.h"
+#include "blockdev.h"
+#include "hw/block-common.h"
+
+#define AT24_BASE_ADDRESS   0x50
+#define AT24_MAX_PAGE_LEN   256
+
+typedef enum AT24TransferState {
+    AT24_IDLE,
+    AT24_RD_ADDR,
+    AT24_WR_ADDR_HI,
+    AT24_WR_ADDR_LO,
+    AT24_RW_DATA0,
+    AT24_RD_DATA,
+    AT24_WR_DATA,
+} AT24TransferState;
+
+typedef struct AT24State {
+    I2CSlave i2c;
+    BlockConf block_conf;
+    BlockDriverState *bs;
+    uint32_t size;
+    bool wp;
+    unsigned int addr_mask;
+    unsigned int page_mask;
+    bool addr16;
+    unsigned int hi_addr_mask;
+    uint8_t device;
+    AT24TransferState transfer_state;
+    uint8_t sector_buffer[BDRV_SECTOR_SIZE];
+    int cached_sector;
+    bool cache_dirty;
+    uint32_t transfer_addr;
+} AT24State;
+
+static void at24_flush_transfer_buffer(AT24State *s)
+{
+    if (s->cached_sector < 0 || !s->cache_dirty) {
+        return;
+    }
+    bdrv_write(s->bs, s->cached_sector, s->sector_buffer, 1);
+    s->cache_dirty = false;
+}
+
+static void at24_event(I2CSlave *i2c, enum i2c_event event, uint8_t param)
+{
+    AT24State *s = DO_UPCAST(AT24State, i2c, i2c);
+
+    switch (event) {
+    case I2C_START_SEND:
+        switch (s->transfer_state) {
+        case AT24_IDLE:
+            if (s->addr16) {
+                s->transfer_addr = (param & s->hi_addr_mask) << 16;
+                s->transfer_state = AT24_WR_ADDR_HI;
+            } else {
+                s->transfer_addr = (param & s->hi_addr_mask) << 8;
+                s->transfer_state = AT24_WR_ADDR_LO;
+            }
+            break;
+        default:
+            s->transfer_state = AT24_IDLE;
+            break;
+        }
+        break;
+    case I2C_START_RECV:
+        switch (s->transfer_state) {
+        case AT24_IDLE:
+            s->transfer_state = AT24_RD_ADDR;
+            break;
+        case AT24_RW_DATA0:
+            s->transfer_state = AT24_RD_DATA;
+            break;
+        default:
+            s->transfer_state = AT24_IDLE;
+            break;
+        }
+        break;
+    case I2C_FINISH:
+        switch (s->transfer_state) {
+        case AT24_WR_DATA:
+            at24_flush_transfer_buffer(s);
+            /* fall through */
+        default:
+            s->transfer_state = AT24_IDLE;
+            break;
+        }
+        break;
+    default:
+        s->transfer_state = AT24_IDLE;
+        break;
+    }
+}
+
+static int at24_cache_sector(AT24State *s, int sector)
+{
+    int ret;
+
+    if (s->cached_sector == sector) {
+        return 0;
+    }
+    ret = bdrv_read(s->bs, sector, s->sector_buffer, 1);
+    if (ret < 0) {
+        s->cached_sector = -1;
+        return ret;
+    }
+    s->cached_sector = sector;
+    s->cache_dirty = false;
+    return 0;
+}
+
+static int at24_tx(I2CSlave *i2c, uint8_t data)
+{
+    AT24State *s = DO_UPCAST(AT24State, i2c, i2c);
+
+    switch (s->transfer_state) {
+    case AT24_WR_ADDR_HI:
+        s->transfer_addr |= (data << 8) & s->addr_mask;
+        s->transfer_state = AT24_WR_ADDR_LO;
+        break;
+    case AT24_WR_ADDR_LO:
+        s->transfer_addr |= data & s->addr_mask;
+        s->transfer_state = AT24_RW_DATA0;
+        break;
+    case AT24_RW_DATA0:
+        s->transfer_state = AT24_WR_DATA;
+        if (at24_cache_sector(s, s->transfer_addr >> BDRV_SECTOR_BITS) < 0 ) {
+            s->transfer_state = AT24_IDLE;
+            return -1;
+        }
+        /* fall through */
+    case AT24_WR_DATA:
+        if (!s->wp) {
+            s->sector_buffer[s->transfer_addr & ~BDRV_SECTOR_MASK] = data;
+            s->cache_dirty = true;
+        }
+        s->transfer_addr = (s->transfer_addr & s->page_mask) |
+            ((s->transfer_addr + 1) & ~s->page_mask);
+        break;
+    default:
+        s->transfer_state = AT24_IDLE;
+        return -1;
+    }
+    return 0;
+}
+
+static int at24_rx(I2CSlave *i2c)
+{
+    AT24State *s = DO_UPCAST(AT24State, i2c, i2c);
+    unsigned int sector, offset;
+    int result;
+
+    switch (s->transfer_state) {
+    case AT24_RD_ADDR:
+        s->transfer_state = AT24_IDLE;
+        result = s->transfer_addr;
+        break;
+    case AT24_RD_DATA:
+        sector = s->transfer_addr >> BDRV_SECTOR_BITS;
+        offset = s->transfer_addr & ~BDRV_SECTOR_MASK;
+        s->transfer_addr = (s->transfer_addr + 1) & s->addr_mask;
+        if (at24_cache_sector(s, sector) < 0 ) {
+            result = 0;
+            break;
+        }
+        result = s->sector_buffer[offset];
+        break;
+    default:
+        s->transfer_state = AT24_IDLE;
+        result = 0;
+        break;
+    }
+    return result;
+}
+
+static void at24_reset(DeviceState *d)
+{
+    AT24State *s = DO_UPCAST(AT24State, i2c.qdev, d);
+
+    s->transfer_state = AT24_IDLE;
+    s->cached_sector = -1;
+}
+
+static int at24_init(I2CSlave *i2c)
+{
+    AT24State *s = DO_UPCAST(AT24State, i2c, i2c);
+    unsigned int page_size;
+    int64_t image_size;
+    int device_bits;
+    int hi_addr_bits;
+    int dev_no;
+
+    assert(AT24_MAX_PAGE_LEN <= BDRV_SECTOR_SIZE);
+
+    s->bs = s->block_conf.bs;
+    if (!s->bs) {
+        error_report("drive property not set");
+        return -1;
+    }
+
+    s->wp = bdrv_is_read_only(s->bs);
+
+    image_size = bdrv_getlength(s->bs);
+    if (s->size == 0) {
+        s->size = image_size;
+    } else if (image_size < s->size) {
+        error_report("image file smaller than specified EEPROM size");
+        return -1;
+    }
+
+    switch (s->size * 8) {
+    case 1*1024:
+    case 2*1024:
+        page_size = 8;
+        device_bits = 3;
+        hi_addr_bits = 0;
+        break;
+    case 4*1024:
+        page_size = 16;
+        device_bits = 2;
+        hi_addr_bits = 1;
+        break;
+    case 8*1024:
+        page_size = 16;
+        device_bits = 1;
+        hi_addr_bits = 2;
+        break;
+    case 16*1024:
+        page_size = 16;
+        device_bits = 0;
+        hi_addr_bits = 3;
+        break;
+    case 32*1024:
+    case 64*1024:
+        page_size = 32;
+        device_bits = 3;
+        hi_addr_bits = 0;
+        s->addr16 = true;
+        break;
+    case 128*1024:
+    case 256*1024:
+        page_size = 64;
+        device_bits = 2;
+        hi_addr_bits = 0;
+        s->addr16 = true;
+        break;
+    case 512*1024:
+        page_size = 128;
+        device_bits = 2;
+        hi_addr_bits = 0;
+        s->addr16 = true;
+        break;
+    case 1024*1024:
+        page_size = 256;
+        device_bits = 1;
+        hi_addr_bits = 1;
+        s->addr16 = true;
+        break;
+    default:
+        error_report("invalid EEPROM size, must be 2^(10..17)");
+        return -1;
+    }
+    s->addr_mask = s->size - 1;
+    s->page_mask = ~(page_size - 1);
+    s->hi_addr_mask = (1 << hi_addr_bits) - 1;
+
+    dev_no = (s->device & ((1 << device_bits) - 1)) << hi_addr_bits;
+    i2c->address = AT24_BASE_ADDRESS | dev_no;
+    i2c->address_mask &= ~s->hi_addr_mask;
+
+    return 0;
+}
+
+static void at24_pre_save(void *opaque)
+{
+    AT24State *s = opaque;
+
+    at24_flush_transfer_buffer(s);
+}
+
+static int at24_post_load(void *opaque, int version_id)
+{
+    AT24State *s = opaque;
+
+    s->cached_sector = -1;
+    return 0;
+}
+
+static const VMStateDescription vmstate_at24 = {
+    .name = "at24",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .pre_save = at24_pre_save,
+    .post_load = at24_post_load,
+    .fields = (VMStateField []) {
+        VMSTATE_UINT32(transfer_state, AT24State),
+        VMSTATE_UINT32(transfer_addr, AT24State),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static Property at24_properties[] = {
+    DEFINE_BLOCK_PROPERTIES(AT24State, block_conf),
+    DEFINE_PROP_UINT8("device", AT24State, device, 0),
+    DEFINE_PROP_UINT32("size", AT24State, size, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void at24_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
+
+    sc->init = at24_init;
+    sc->event = at24_event;
+    sc->recv = at24_rx;
+    sc->send = at24_tx;
+    dc->desc = "AT24Cxx EEPROM";
+    dc->reset = at24_reset;
+    dc->vmsd = &vmstate_at24;
+    dc->props = at24_properties;
+}
+
+static TypeInfo at24_info = {
+    .name          = "at24",
+    .parent        = TYPE_I2C_SLAVE,
+    .instance_size = sizeof(AT24State),
+    .class_init    = at24_class_init,
+};
+
+static void at24_register_types(void)
+{
+    type_register_static(&at24_info);
+}
+
+type_init(at24_register_types)