[Qemu-devel] [PATCH 05/17] timer: generalize Dallas/Maxim RTC i2c devices

[Michael Davidsaver <mdavidsaver@gmail.com>]

Support for: ds1307, ds1337, ds1338, ds1339,
ds1340, ds1375, ds1388, and ds3231.

Tested with ds1338 and ds1375.

Signed-off-by: Michael Davidsaver <mdavidsaver@gmail.com>
---
 default-configs/arm-softmmu.mak |   2 +-
 hw/timer/Makefile.objs          |   2 +-
 hw/timer/ds-rtc-i2c.c           | 461 ++++++++++++++++++++++++++++++++++++++++
 hw/timer/ds1338.c               | 239 ---------------------
 4 files changed, 463 insertions(+), 241 deletions(-)
 create mode 100644 hw/timer/ds-rtc-i2c.c
 delete mode 100644 hw/timer/ds1338.c

diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
index d37edc4312..b857823681 100644
--- a/default-configs/arm-softmmu.mak
+++ b/default-configs/arm-softmmu.mak
@@ -31,7 +31,7 @@ CONFIG_SMC91C111=y
 CONFIG_ALLWINNER_EMAC=y
 CONFIG_IMX_FEC=y
 CONFIG_FTGMAC100=y
-CONFIG_DS1338=y
+CONFIG_DSRTCI2C=y
 CONFIG_PFLASH_CFI01=y
 CONFIG_PFLASH_CFI02=y
 CONFIG_MICRODRIVE=y
diff --git a/hw/timer/Makefile.objs b/hw/timer/Makefile.objs
index 8c19eac3b6..290015ebec 100644
--- a/hw/timer/Makefile.objs
+++ b/hw/timer/Makefile.objs
@@ -3,7 +3,7 @@ common-obj-$(CONFIG_ARM_MPTIMER) += arm_mptimer.o
 common-obj-$(CONFIG_ARM_V7M) += armv7m_systick.o
 common-obj-$(CONFIG_A9_GTIMER) += a9gtimer.o
 common-obj-$(CONFIG_CADENCE) += cadence_ttc.o
-common-obj-$(CONFIG_DS1338) += ds1338.o
+common-obj-$(CONFIG_DSRTCI2C) += ds-rtc-i2c.o
 common-obj-$(CONFIG_HPET) += hpet.o
 common-obj-$(CONFIG_I8254) += i8254_common.o i8254.o
 common-obj-$(CONFIG_M48T59) += m48t59.o
diff --git a/hw/timer/ds-rtc-i2c.c b/hw/timer/ds-rtc-i2c.c
new file mode 100644
index 0000000000..ad2f8f2a68
--- /dev/null
+++ b/hw/timer/ds-rtc-i2c.c
@@ -0,0 +1,461 @@
+/* Emulation of various Dallas/Maxim RTCs accessed via I2C bus
+ *
+ * Copyright (c) 2017 Michael Davidsaver
+ * Copyright (c) 2009 CodeSourcery
+ *
+ * Authors: Michael Davidsaver
+ *          Paul Brook
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the LICENSE file in the top-level directory.
+ *
+ * Models real time read/set and NVRAM.
+ * Does not model alarms, or control/status registers.
+ *
+ * Generalized register map is:
+ *   [Current time]
+ *   [Alarm settings] (optional)
+ *   [Control/Status] (optional)
+ *   [Non-volatile memory] (optional)
+ *
+ * The current time registers are almost always the same,
+ * with the exception being that some have a CENTURY bit
+ * in the month register.
+ */
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/timer.h"
+#include "qemu/bcd.h"
+#include "hw/hw.h"
+#include "hw/registerfields.h"
+#include "hw/i2c/i2c.h"
+#include "sysemu/qtest.h"
+#include "qemu/error-report.h"
+
+/* #define DEBUG_DSRTC */
+
+#ifdef DEBUG_DSRTC
+#define DPRINTK(FMT, ...) info_report(TYPE_DSRTC " : " FMT, ## __VA_ARGS__)
+#else
+#define DPRINTK(FMT, ...) do {} while (0)
+#endif
+
+#define LOG(MSK, FMT, ...) qemu_log_mask(MSK, TYPE_DSRTC " : " FMT "\n", \
+                            ## __VA_ARGS__)
+
+#define DSRTC_REGSIZE (0x40)
+
+/* values stored in BCD */
+/* 00-59 */
+#define R_SEC   (0x0)
+/* 00-59 */
+#define R_MIN   (0x1)
+#define R_HOUR  (0x2)
+/* 1-7 */
+#define R_WDAY  (0x3)
+/* 0-31 */
+#define R_DATE  (0x4)
+#define R_MONTH (0x5)
+/* 0-99 */
+#define R_YEAR  (0x6)
+
+/* use 12 hour mode when set */
+FIELD(HOUR, SET12, 6, 1)
+/* 00-23 */
+FIELD(HOUR, HOUR24, 0, 6)
+FIELD(HOUR, AMPM, 5, 1)
+/* 1-12 (not 0-11!) */
+FIELD(HOUR, HOUR12, 0, 5)
+
+/* 1-12 */
+FIELD(MONTH, MONTH, 0, 5)
+FIELD(MONTH, CENTURY, 7, 1)
+
+typedef struct DSRTCInfo {
+    /* if bit 7 of the Month register is set after Y2K */
+    bool has_century;
+    /* address of first non-volatile memory cell.
+     * nv_start >= reg_end means no NV memory.
+     */
+    uint8_t nv_start;
+    /* total size of register range.  When address counter rolls over. */
+    uint8_t reg_size;
+} DSRTCInfo;
+
+typedef struct DSRTCState {
+    I2CSlave parent_obj;
+
+    const DSRTCInfo *info;
+
+    qemu_irq alarm_irq;
+
+    /* register address counter */
+    uint8_t addr;
+    /* when writing, whether the address has been sent */
+    bool addrd;
+
+    int64_t time_offset;
+    int8_t wday_offset;
+
+    uint8_t regs[DSRTC_REGSIZE];
+} DSRTCState;
+
+typedef struct DSRTCClass {
+    I2CSlaveClass parent_class;
+
+    const DSRTCInfo *info;
+} DSRTCClass;
+
+#define TYPE_DSRTC "ds-rtc-i2c"
+#define DSRTC(obj) OBJECT_CHECK(DSRTCState, (obj), TYPE_DSRTC)
+#define DSRTC_GET_CLASS(obj) \
+    OBJECT_GET_CLASS(DSRTCClass, obj, TYPE_DSRTC)
+#define DSRTC_CLASS(klass) \
+    OBJECT_CLASS_CHECK(DSRTCClass, klass, TYPE_DSRTC)
+
+static const VMStateDescription vmstate_dsrtc = {
+    .name = TYPE_DSRTC,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_I2C_SLAVE(parent_obj, DSRTCState),
+        VMSTATE_INT64(time_offset, DSRTCState),
+        VMSTATE_INT8_V(wday_offset, DSRTCState, 2),
+        VMSTATE_UINT8_ARRAY(regs, DSRTCState, DSRTC_REGSIZE),
+        VMSTATE_UINT8(addr, DSRTCState),
+        VMSTATE_BOOL(addrd, DSRTCState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void dsrtc_reset(DeviceState *device);
+
+/* update current time registers */
+static
+void dsrtc_latch(DSRTCState *ds)
+{
+    struct tm now;
+    bool use12;
+
+    qemu_get_timedate(&now, ds->time_offset);
+
+    DPRINTK("Current Time %3u/%2u/%u %2u:%2u:%2u (wday %u)",
+            now.tm_year, now.tm_mon, now.tm_mday,
+            now.tm_hour, now.tm_min, now.tm_sec,
+            now.tm_wday);
+
+    use12 = ARRAY_FIELD_EX32(ds->regs, HOUR, SET12);
+
+    /* ensure unused bits are zero */
+    memset(ds->regs, 0, R_YEAR + 1);
+
+    ds->regs[R_SEC] = to_bcd(now.tm_sec);
+    ds->regs[R_MIN] = to_bcd(now.tm_min);
+
+    if (!use12) {
+        /* 24 hour (0-23) */
+        ARRAY_FIELD_DP32(ds->regs, HOUR, HOUR24, to_bcd(now.tm_hour));
+    } else {
+        /* 12 hour am/pm (1-12) */
+        ARRAY_FIELD_DP32(ds->regs, HOUR, SET12, 1);
+        ARRAY_FIELD_DP32(ds->regs, HOUR, AMPM, now.tm_hour >= 12u);
+        ARRAY_FIELD_DP32(ds->regs, HOUR, HOUR12,
+                         to_bcd(1u + (now.tm_hour % 12u)));
+    }
+
+    ds->regs[R_WDAY] = (now.tm_wday + ds->wday_offset) % 7u + 1u;
+    ds->regs[R_DATE] = to_bcd(now.tm_mday);
+
+    ARRAY_FIELD_DP32(ds->regs, MONTH, MONTH, to_bcd(now.tm_mon + 1));
+    if (ds->info->has_century) {
+        ARRAY_FIELD_DP32(ds->regs, MONTH, CENTURY, now.tm_year >= 100u);
+    }
+
+    ds->regs[R_YEAR] = to_bcd(now.tm_year % 100u);
+
+    DPRINTK("Latched time");
+}
+
+/* call after guest writes to current time registers
+ * to re-compute our offset from host time.
+ */
+static
+void dsrtc_update(DSRTCState *ds)
+{
+    int user_wday;
+    struct tm now;
+
+    now.tm_sec = from_bcd(ds->regs[R_SEC]);
+    now.tm_min = from_bcd(ds->regs[R_MIN]);
+
+    if (ARRAY_FIELD_EX32(ds->regs, HOUR, SET12)) {
+        /* 12 hour (1-12) */
+        now.tm_hour = from_bcd(ARRAY_FIELD_EX32(ds->regs, HOUR, HOUR12)) - 1u;
+        if (ARRAY_FIELD_EX32(ds->regs, HOUR, AMPM)) {
+            now.tm_hour += 12;
+        }
+
+    } else {
+        /* 23 hour (0-23) */
+        now.tm_hour = from_bcd(ARRAY_FIELD_EX32(ds->regs, HOUR, HOUR24));
+    }
+
+    now.tm_wday = from_bcd(ds->regs[R_WDAY]) - 1u;
+    now.tm_mday = from_bcd(ds->regs[R_DATE]);
+    now.tm_mon = from_bcd(ARRAY_FIELD_EX32(ds->regs, MONTH, MONTH)) - 1;
+
+    now.tm_year = from_bcd(ds->regs[R_YEAR]);
+    if (ARRAY_FIELD_EX32(ds->regs, MONTH, CENTURY) || !ds->info->has_century) {
+        now.tm_year += 100;
+    }
+
+    DPRINTK("New Time %3u/%2u/%u %2u:%2u:%2u (wday %u)",
+            now.tm_year, now.tm_mon, now.tm_mday,
+            now.tm_hour, now.tm_min, now.tm_sec,
+            now.tm_wday);
+
+    /* round trip to get real wday_offset based on time delta */
+    user_wday = now.tm_wday;
+    ds->time_offset = qemu_timedate_diff(&now);
+    /* race possible if we run at midnight
+     * TODO: make qemu_timedate_diff() calculate wday offset as well?
+     */
+    qemu_get_timedate(&now, ds->time_offset);
+    /* calculate wday_offset to achieve guest requested wday */
+    ds->wday_offset = user_wday - now.tm_wday;
+
+    DPRINTK("Update offset = %" PRId64 ", wday_offset = %d",
+            ds->time_offset, ds->wday_offset);
+}
+
+static
+void dsrtc_advance(DSRTCState *ds)
+{
+    ds->addr = (ds->addr + 1) % ds->info->reg_size;
+    if (ds->addr == 0) {
+        /* latch time on roll over */
+        dsrtc_latch(ds);
+    }
+}
+
+static
+int dsrtc_event(I2CSlave *s, enum i2c_event event)
+{
+    DSRTCState *ds = DSRTC(s);
+
+    switch (event) {
+    case I2C_START_SEND:
+        ds->addrd = false;
+        /* fall through */
+    case I2C_START_RECV:
+        dsrtc_latch(ds);
+        /* fall through */
+    case I2C_FINISH:
+        DPRINTK("Event %d", (int)event);
+        /* fall through */
+    case I2C_NACK:
+        break;
+    }
+    return 0;
+}
+
+static
+int dsrtc_recv(I2CSlave *s)
+{
+    DSRTCState *ds = DSRTC(s);
+    int ret = 0;
+
+    ret = ds->regs[ds->addr];
+
+    if (ds->addr > R_YEAR && ds->addr < ds->info->nv_start) {
+        LOG(LOG_UNIMP, "Read from unimplemented (%02x) %02x", ds->addr, ret);
+    }
+
+    DPRINTK("Recv (%02x) %02x", ds->addr, ret);
+
+    dsrtc_advance(ds);
+
+    return ret;
+}
+
+static
+int dsrtc_send(I2CSlave *s, uint8_t data)
+{
+    DSRTCState *ds = DSRTC(s);
+
+    if (!ds->addrd) {
+        if (data == 0xff && qtest_enabled()) {
+            /* allow test runner to zero offsets */
+            DPRINTK("Testing reset");
+            dsrtc_reset(DEVICE(s));
+            return 0;
+        }
+        ds->addr = data % DSRTC_REGSIZE;
+        ds->addrd = true;
+        DPRINTK("Set address pointer %02x", data);
+        return 0;
+    }
+
+    DPRINTK("Send (%02x) %02x", ds->addr, data);
+
+    if (ds->addr <= R_YEAR) {
+        ds->regs[ds->addr] = data;
+        dsrtc_update(ds);
+
+    } else if (ds->addr >= ds->info->nv_start) {
+        ds->regs[ds->addr] = data;
+
+    } else {
+        LOG(LOG_UNIMP, "Register not modeled");
+    }
+
+    dsrtc_advance(ds);
+
+    return 0;
+}
+
+static
+void dsrtc_reset(DeviceState *device)
+{
+    DSRTCState *ds = DSRTC(device);
+
+    memset(ds->regs, 0, sizeof(ds->regs));
+
+    ds->addr = 0;
+    ds->addrd = false;
+    ds->time_offset = 0;
+    ds->wday_offset = 0;
+
+    DPRINTK("Reset");
+}
+
+static
+void dsrtc_realize(DeviceState *device, Error **errp)
+{
+    DSRTCState *ds = DSRTC(device);
+    DSRTCClass *r = DSRTC_GET_CLASS(device);
+
+    ds->info = r->info;
+
+    /* Alarms not yet implemented, but allow
+     * board code to wire up the alarm interrupt
+     * output anyway.
+     */
+    qdev_init_gpio_out(device, &ds->alarm_irq, 1);
+}
+
+static
+void dsrtc_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
+    DSRTCClass *r = DSRTC_CLASS(klass);
+
+    r->info = data;
+
+    k->event = &dsrtc_event;
+    k->recv = &dsrtc_recv;
+    k->send = &dsrtc_send;
+
+    dc->vmsd = &vmstate_dsrtc;
+    dc->realize = dsrtc_realize;
+    dc->reset = dsrtc_reset;
+    dc->user_creatable = true;
+}
+
+static
+const TypeInfo ds_rtc_base_type = {
+    .abstract = true,
+    .name = TYPE_DSRTC,
+    .parent = TYPE_I2C_SLAVE,
+    .instance_size = sizeof(DSRTCState),
+};
+
+#define DSRTC_CONFIG(NAME) \
+static const TypeInfo NAME##_type = { \
+    .name = #NAME, \
+    .parent = TYPE_DSRTC, \
+    .class_size = sizeof(I2CSlaveClass), \
+    .class_init = dsrtc_class_init, \
+    .class_data = (void *)&NAME##_info, \
+};
+
+/* ds3231 - alarms, no eeprom */
+static const DSRTCInfo ds3231_info = {
+    .has_century = true,
+    .nv_start    = 0x13, /* no nv memory */
+    .reg_size    = 0x13,
+};
+DSRTC_CONFIG(ds3231)
+
+/* only model block 0 (RTC), blocks 1,2 (eeprom) not modeled.
+ * blocks have different i2c addresses
+ */
+static const DSRTCInfo ds1388_info = {
+    .has_century = false,
+    .nv_start    = 0x0d,
+    .reg_size    = 0x0d,
+};
+DSRTC_CONFIG(ds1388)
+
+/* alarms, eeprom */
+static const DSRTCInfo ds1375_info = {
+    .has_century = true,
+    .nv_start    = 0x10,
+    .reg_size    = 0x20,
+};
+DSRTC_CONFIG(ds1375)
+
+/* no alarms, no eeprom */
+static const DSRTCInfo ds1340_info = {
+    .has_century = false,
+    .nv_start    = 0x10,
+    .reg_size    = 0x10,
+};
+DSRTC_CONFIG(ds1340)
+
+/* alarms, no eeprom */
+static const DSRTCInfo ds1339_info = {
+    .has_century = false,
+    .nv_start    = 0x11,
+    .reg_size    = 0x11,
+};
+DSRTC_CONFIG(ds1339)
+
+/* no alarms, eeprom */
+static const DSRTCInfo ds1338_info = {
+    .has_century = false,
+    .nv_start    = 0x08,
+    .reg_size    = 0x40,
+};
+DSRTC_CONFIG(ds1338)
+
+/* alarms, no eeprom */
+static const DSRTCInfo ds1337_info = {
+    .has_century = true,
+    .nv_start    = 0x10,
+    .reg_size    = 0x10,
+};
+DSRTC_CONFIG(ds1337)
+
+/* ds1307 registers are identical to ds1338 */
+static
+const TypeInfo ds1307_type = {
+    .name = "ds1307",
+    .parent = "ds1338",
+};
+
+static void ds_rtc_i2c_register(void)
+{
+    type_register_static(&ds_rtc_base_type);
+    type_register_static(&ds3231_type);
+    type_register_static(&ds1388_type);
+    type_register_static(&ds1375_type);
+    type_register_static(&ds1340_type);
+    type_register_static(&ds1339_type);
+    type_register_static(&ds1338_type);
+    type_register_static(&ds1337_type);
+    type_register_static(&ds1307_type);
+}
+
+type_init(ds_rtc_i2c_register)
diff --git a/hw/timer/ds1338.c b/hw/timer/ds1338.c
deleted file mode 100644
index 3849b74a68..0000000000
--- a/hw/timer/ds1338.c
+++ /dev/null
@@ -1,239 +0,0 @@
-/*
- * MAXIM DS1338 I2C RTC+NVRAM
- *
- * Copyright (c) 2009 CodeSourcery.
- * Written by Paul Brook
- *
- * This code is licensed under the GNU GPL v2.
- *
- * Contributions after 2012-01-13 are licensed under the terms of the
- * GNU GPL, version 2 or (at your option) any later version.
- */
-
-#include "qemu/osdep.h"
-#include "qemu-common.h"
-#include "hw/i2c/i2c.h"
-#include "qemu/bcd.h"
-
-/* Size of NVRAM including both the user-accessible area and the
- * secondary register area.
- */
-#define NVRAM_SIZE 64
-
-/* Flags definitions */
-#define SECONDS_CH 0x80
-#define HOURS_12   0x40
-#define HOURS_PM   0x20
-#define CTRL_OSF   0x20
-
-#define TYPE_DS1338 "ds1338"
-#define DS1338(obj) OBJECT_CHECK(DS1338State, (obj), TYPE_DS1338)
-
-typedef struct DS1338State {
-    I2CSlave parent_obj;
-
-    int64_t offset;
-    uint8_t wday_offset;
-    uint8_t nvram[NVRAM_SIZE];
-    int32_t ptr;
-    bool addr_byte;
-} DS1338State;
-
-static const VMStateDescription vmstate_ds1338 = {
-    .name = "ds1338",
-    .version_id = 2,
-    .minimum_version_id = 1,
-    .fields = (VMStateField[]) {
-        VMSTATE_I2C_SLAVE(parent_obj, DS1338State),
-        VMSTATE_INT64(offset, DS1338State),
-        VMSTATE_UINT8_V(wday_offset, DS1338State, 2),
-        VMSTATE_UINT8_ARRAY(nvram, DS1338State, NVRAM_SIZE),
-        VMSTATE_INT32(ptr, DS1338State),
-        VMSTATE_BOOL(addr_byte, DS1338State),
-        VMSTATE_END_OF_LIST()
-    }
-};
-
-static void capture_current_time(DS1338State *s)
-{
-    /* Capture the current time into the secondary registers
-     * which will be actually read by the data transfer operation.
-     */
-    struct tm now;
-    qemu_get_timedate(&now, s->offset);
-    s->nvram[0] = to_bcd(now.tm_sec);
-    s->nvram[1] = to_bcd(now.tm_min);
-    if (s->nvram[2] & HOURS_12) {
-        int tmp = now.tm_hour;
-        if (tmp % 12 == 0) {
-            tmp += 12;
-        }
-        if (tmp <= 12) {
-            s->nvram[2] = HOURS_12 | to_bcd(tmp);
-        } else {
-            s->nvram[2] = HOURS_12 | HOURS_PM | to_bcd(tmp - 12);
-        }
-    } else {
-        s->nvram[2] = to_bcd(now.tm_hour);
-    }
-    s->nvram[3] = (now.tm_wday + s->wday_offset) % 7 + 1;
-    s->nvram[4] = to_bcd(now.tm_mday);
-    s->nvram[5] = to_bcd(now.tm_mon + 1);
-    s->nvram[6] = to_bcd(now.tm_year - 100);
-}
-
-static void inc_regptr(DS1338State *s)
-{
-    /* The register pointer wraps around after 0x3F; wraparound
-     * causes the current time/date to be retransferred into
-     * the secondary registers.
-     */
-    s->ptr = (s->ptr + 1) & (NVRAM_SIZE - 1);
-    if (!s->ptr) {
-        capture_current_time(s);
-    }
-}
-
-static int ds1338_event(I2CSlave *i2c, enum i2c_event event)
-{
-    DS1338State *s = DS1338(i2c);
-
-    switch (event) {
-    case I2C_START_RECV:
-        /* In h/w, capture happens on any START condition, not just a
-         * START_RECV, but there is no need to actually capture on
-         * START_SEND, because the guest can't get at that data
-         * without going through a START_RECV which would overwrite it.
-         */
-        capture_current_time(s);
-        break;
-    case I2C_START_SEND:
-        s->addr_byte = true;
-        break;
-    default:
-        break;
-    }
-
-    return 0;
-}
-
-static int ds1338_recv(I2CSlave *i2c)
-{
-    DS1338State *s = DS1338(i2c);
-    uint8_t res;
-
-    res  = s->nvram[s->ptr];
-    inc_regptr(s);
-    return res;
-}
-
-static int ds1338_send(I2CSlave *i2c, uint8_t data)
-{
-    DS1338State *s = DS1338(i2c);
-
-    if (s->addr_byte) {
-        s->ptr = data & (NVRAM_SIZE - 1);
-        s->addr_byte = false;
-        return 0;
-    }
-    if (s->ptr < 7) {
-        /* Time register. */
-        struct tm now;
-        qemu_get_timedate(&now, s->offset);
-        switch(s->ptr) {
-        case 0:
-            /* TODO: Implement CH (stop) bit.  */
-            now.tm_sec = from_bcd(data & 0x7f);
-            break;
-        case 1:
-            now.tm_min = from_bcd(data & 0x7f);
-            break;
-        case 2:
-            if (data & HOURS_12) {
-                int tmp = from_bcd(data & (HOURS_PM - 1));
-                if (data & HOURS_PM) {
-                    tmp += 12;
-                }
-                if (tmp % 12 == 0) {
-                    tmp -= 12;
-                }
-                now.tm_hour = tmp;
-            } else {
-                now.tm_hour = from_bcd(data & (HOURS_12 - 1));
-            }
-            break;
-        case 3:
-            {
-                /* The day field is supposed to contain a value in
-                   the range 1-7. Otherwise behavior is undefined.
-                 */
-                int user_wday = (data & 7) - 1;
-                s->wday_offset = (user_wday - now.tm_wday + 7) % 7;
-            }
-            break;
-        case 4:
-            now.tm_mday = from_bcd(data & 0x3f);
-            break;
-        case 5:
-            now.tm_mon = from_bcd(data & 0x1f) - 1;
-            break;
-        case 6:
-            now.tm_year = from_bcd(data) + 100;
-            break;
-        }
-        s->offset = qemu_timedate_diff(&now);
-    } else if (s->ptr == 7) {
-        /* Control register. */
-
-        /* Ensure bits 2, 3 and 6 will read back as zero. */
-        data &= 0xB3;
-
-        /* Attempting to write the OSF flag to logic 1 leaves the
-           value unchanged. */
-        data = (data & ~CTRL_OSF) | (data & s->nvram[s->ptr] & CTRL_OSF);
-
-        s->nvram[s->ptr] = data;
-    } else {
-        s->nvram[s->ptr] = data;
-    }
-    inc_regptr(s);
-    return 0;
-}
-
-static void ds1338_reset(DeviceState *dev)
-{
-    DS1338State *s = DS1338(dev);
-
-    /* The clock is running and synchronized with the host */
-    s->offset = 0;
-    s->wday_offset = 0;
-    memset(s->nvram, 0, NVRAM_SIZE);
-    s->ptr = 0;
-    s->addr_byte = false;
-}
-
-static void ds1338_class_init(ObjectClass *klass, void *data)
-{
-    DeviceClass *dc = DEVICE_CLASS(klass);
-    I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
-
-    k->event = ds1338_event;
-    k->recv = ds1338_recv;
-    k->send = ds1338_send;
-    dc->reset = ds1338_reset;
-    dc->vmsd = &vmstate_ds1338;
-}
-
-static const TypeInfo ds1338_info = {
-    .name          = TYPE_DS1338,
-    .parent        = TYPE_I2C_SLAVE,
-    .instance_size = sizeof(DS1338State),
-    .class_init    = ds1338_class_init,
-};
-
-static void ds1338_register_types(void)
-{
-    type_register_static(&ds1338_info);
-}
-
-type_init(ds1338_register_types)
-- 
2.11.0