plat/qemu: Add LPC based RTC support

This adds a driver for standard CMOS RTC chips and use it from
the QEMU platform.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/include/time-utils.h b/include/time-utils.h
index 721b6f7e..e0a9a98d 100644
--- a/include/time-utils.h
+++ b/include/time-utils.h
@@ -20,6 +20,24 @@
 #include <stdint.h>
 #include <time.h>
 
+/* BCD conversion utilities. MSB is byte 3, LSB is byte 0 */
+
+static inline unsigned int bcd_byte(uint32_t bcd, int byteno)
+{
+	bcd >>= byteno * 8;
+	return (bcd >> 4 & 0xf) * 10 + (bcd & 0xf);
+}
+
+static inline uint32_t int_to_bcd2(unsigned int x)
+{
+	return (((x / 10) << 4) & 0xf0) | (x % 10);
+}
+
+static inline uint32_t int_to_bcd4(unsigned int x)
+{
+	return int_to_bcd2(x / 100) << 8 | int_to_bcd2(x % 100);
+}
+
 void tm_to_datetime(struct tm *tm, uint32_t *y_m_d, uint64_t *h_m_s_m);
 void datetime_to_tm(uint32_t y_m_d, uint64_t h_m_s_m, struct tm *tm);