1 files changed, 20 insertions, 0 deletions
diff --git a/include/hw/timer/mc146818rtc_regs.h b/include/hw/timer/mc146818rtc_regs.h
index 6ede6c832e..c62f17bf2d 100644
--- a/include/hw/timer/mc146818rtc_regs.h
+++ b/include/hw/timer/mc146818rtc_regs.h
@@ -65,4 +65,24 @@
 #define REG_C_AF   0x20
 #define REG_C_MASK 0x70
 
+static inline uint32_t periodic_period_to_clock(int period_code)
+{
+    if (!period_code) {
+        return 0;
+   }
+
+    if (period_code <= 2) {
+        period_code += 7;
+    }
+    /* period in 32 Khz cycles */
+   return 1 << (period_code - 1);
+}
+
+#define RTC_CLOCK_RATE            32768
+
+static inline int64_t periodic_clock_to_ns(int64_t clocks)
+{
+    return muldiv64(clocks, NANOSECONDS_PER_SECOND, RTC_CLOCK_RATE);
+}
+
 #endif