[Qemu-devel] [PATCH 10/15] BACKPORT: Add rtc reset function.

[Glauber Costa <glommer@redhat.com>]

From: Gleb Natapov <gleb@redhat.com>

On reset:
Periodic Interrupt Enable (PIE) bit is cleared to zero
Alarm Interrupt Enable (AIE) bit is cleared to zero
Update ended Interrupt Flag (UF) bit is cleared to zero
Interrupt Request status Flag (IRQF) bit is cleared to zero
Periodic Interrupt Flag (PF) bit is cleared to zero
Alarm Interrupt Flag (AF) bit is cleared to zero
Square Wave output Enable (SQWE) zero

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 hw/mc146818rtc.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
index 5b08d72..30a74ee 100644
--- a/hw/mc146818rtc.c
+++ b/hw/mc146818rtc.c
@@ -56,6 +56,11 @@
 #define REG_B_UIE 0x10
 #define REG_B_DM  0x04
 
+#define REG_C_UF   0x10
+#define REG_C_IRQF 0x80
+#define REG_C_PF   0x40
+#define REG_C_AF   0x20
+
 struct RTCState {
     uint8_t cmos_data[128];
     uint8_t cmos_index;
@@ -527,6 +532,21 @@ static int rtc_load_td(QEMUFile *f, void *opaque, int version_id)
 }
 #endif
 
+static void rtc_reset(void *opaque)
+{
+    RTCState *s = opaque;
+
+    s->cmos_data[RTC_REG_B] &= ~(REG_B_PIE | REG_B_AIE);
+    s->cmos_data[RTC_REG_C] &= ~(REG_C_UF | REG_C_IRQF | REG_C_PF | REG_C_AF);
+
+    qemu_irq_lower(s->irq);
+
+#ifdef TARGET_I386
+    if (rtc_td_hack)
+	    s->irq_coalesced = 0;
+#endif
+}
+
 RTCState *rtc_init(int base, qemu_irq irq, int base_year)
 {
     RTCState *s;
@@ -560,6 +580,8 @@ RTCState *rtc_init(int base, qemu_irq irq, int base_year)
     if (rtc_td_hack)
         register_savevm("mc146818rtc-td", base, 1, rtc_save_td, rtc_load_td, s);
 #endif
+    qemu_register_reset(rtc_reset, s);
+
     return s;
 }
 
@@ -670,5 +692,6 @@ RTCState *rtc_mm_init(target_phys_addr_t base, int it_shift, qemu_irq irq,
     if (rtc_td_hack)
         register_savevm("mc146818rtc-td", base, 1, rtc_save_td, rtc_load_td, s);
 #endif
+    qemu_register_reset(rtc_reset, s);
     return s;
 }
-- 
1.6.2.2