From: Peng Hao <peng.hao2@zte.com.cn>

Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
Message-Id: <1539890353-30273-1-git-send-email-peng.hao2@zte.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/timer/mc146818rtc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index acee47d..e4e4de8 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -34,6 +34,7 @@
 #include "qapi/qapi-commands-misc.h"
 #include "qapi/qapi-events-misc.h"
 #include "qapi/visitor.h"
+#include "exec/address-spaces.h"
 
 #ifdef TARGET_I386
 #include "hw/i386/apic.h"
@@ -70,6 +71,7 @@ typedef struct RTCState {
     ISADevice parent_obj;
 
     MemoryRegion io;
+    MemoryRegion coalesced_io;
     uint8_t cmos_data[128];
     uint8_t cmos_index;
     int32_t base_year;
@@ -990,6 +992,13 @@ static void rtc_realizefn(DeviceState *dev, Error **errp)
     memory_region_init_io(&s->io, OBJECT(s), &cmos_ops, s, "rtc", 2);
     isa_register_ioport(isadev, &s->io, base);
 
+    /* register rtc 0x70 port for coalesced_pio */
+    memory_region_set_flush_coalesced(&s->io);
+    memory_region_init_io(&s->coalesced_io, OBJECT(s), &cmos_ops,
+                          s, "rtc-index", 1);
+    memory_region_add_subregion(&s->io, 0, &s->coalesced_io);
+    memory_region_add_coalescing(&s->coalesced_io, 0, 1);
+
     qdev_set_legacy_instance_id(dev, base, 3);
     qemu_register_reset(rtc_reset, s);
 
-- 
1.8.3.1