PcAtChipsetPkg/PcRtc: Fix a Y2K bug

The original driver cannot handle the case when system time runs from 1999/12/31 23:59:59
to 2000/1/1 0:0:0.
A simple test to set system time to 1999/12/31 23:59:59 can expose this bug.
The patch limits the driver to only support year in 100 range and decide the century value based
on the supporting range: Century either equals to PcdMinimalYear / 100 or equals to PcdMinimalYear / 100 + 1.

The patch passed the Y2K test.
However with year range [1998, 2097], when system time is 2097/12/31 23:59:59,
the next second system time will become 1998/1/1 0:0:0. I think it's a acceptable limitation.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17624 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 2 insertions, 9 deletions

diff --git a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.h b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.h
index 020d7153a5..026c1086b2 100644
--- a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.h
+++ b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcRtc.h
@@ -1,7 +1,7 @@
 /** @file

   Header file for real time clock driver.

 

-Copyright (c) 2006 - 2007, Intel Corporation. All rights reserved.<BR>

+Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>

 This program and the accompanying materials

 are licensed and made available under the terms and conditions of the BSD License

 which accompanies this distribution.  The full text of the license may be found at

@@ -61,7 +61,6 @@ typedef struct {
 #define RTC_ADDRESS_REGISTER_B        11  // R/W

 #define RTC_ADDRESS_REGISTER_C        12  // RO

 #define RTC_ADDRESS_REGISTER_D        13  // RO

-#define RTC_ADDRESS_CENTURY           50  // R/W  Range 19..20 Bit 8 is R/W

 //

 // Date and time initial values.

 // They are used if the RTC values are invalid during driver initialization

@@ -71,7 +70,6 @@ typedef struct {
 #define RTC_INIT_HOUR   0

 #define RTC_INIT_DAY    1

 #define RTC_INIT_MONTH  1

-#define RTC_INIT_YEAR   2001

 

 //

 // Register initial values

@@ -287,14 +285,11 @@ RtcTimeFieldsValid (
   @param   Time       On input, the time data read from UEFI to convert

                       On output, the time converted to RTC format

   @param   RegisterB  Value of Register B of RTC, indicating data mode

-  @param   Century    It is set according to EFI_TIME Time.

-

 **/

 VOID

 ConvertEfiTimeToRtcTime (

   IN OUT EFI_TIME        *Time,

-  IN     RTC_REGISTER_B  RegisterB,

-  OUT    UINT8           *Century

+  IN     RTC_REGISTER_B  RegisterB

   );

 

 

@@ -308,7 +303,6 @@ ConvertEfiTimeToRtcTime (
 

   @param   Time       On input, the time data read from RTC to convert

                       On output, the time converted to UEFI format

-  @param   Century    Value of century read from RTC.

   @param   RegisterB  Value of Register B of RTC, indicating data mode

                       and hour format.

 

@@ -319,7 +313,6 @@ ConvertEfiTimeToRtcTime (
 EFI_STATUS

 ConvertRtcTimeToEfiTime (

   IN OUT EFI_TIME        *Time,

-  IN     UINT8           Century,

   IN     RTC_REGISTER_B  RegisterB

   );