PcAtChipsetPkg: Add MMIO Support to RTC driver

Some virtual machine managers like Kvmtool emulate the MC146818
RTC controller in the MMIO space so that architectures that do
not support I/O Mapped I/O can use the RTC. This patch adds MMIO
support to the RTC controller driver.

The PCD PcdRtcUseMmio has been added to select I/O or MMIO support.
  If PcdRtcUseMmio is:
    TRUE  - Indicates the RTC port registers are in MMIO space.
    FALSE - Indicates the RTC port registers are in I/O space.
            Default is I/O space.

Additionally two new PCDs PcdRtcIndexRegister64 and
PcdRtcTargetRegister64 have been introduced to provide the base
address for the RTC registers in the MMIO space.

When MMIO support is selected (PcdRtcUseMmio == TRUE) the driver
converts the pointers to the RTC MMIO registers so that the
RTC registers are accessible post ExitBootServices.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcatRealTimeClockRuntimeDxe.inf b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcatRealTimeClockRuntimeDxe.inf
index c73ee98..0d8eca2 100644
--- a/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcatRealTimeClockRuntimeDxe.inf
+++ b/PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcatRealTimeClockRuntimeDxe.inf
@@ -6,6 +6,7 @@
 #

 # Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>

 # Copyright (c) 2017, AMD Inc. All rights reserved.<BR>

+# Copyright (c) 2018 - 2020, ARM Limited. All rights reserved.<BR>

 #

 # SPDX-License-Identifier: BSD-2-Clause-Patent

 #

@@ -61,6 +62,11 @@
   ## SOMETIMES_CONSUMES ## SystemTable

   gEfiAcpiTableGuid

 

+  gEfiEventVirtualAddressChangeGuid

+

+[FeaturePcd]

+  gPcAtChipsetPkgTokenSpaceGuid.PcdRtcUseMmio                   ## CONSUMES

+

 [FixedPcd]

   gPcAtChipsetPkgTokenSpaceGuid.PcdInitialValueRtcRegisterA     ## CONSUMES

   gPcAtChipsetPkgTokenSpaceGuid.PcdInitialValueRtcRegisterB     ## CONSUMES

@@ -72,6 +78,8 @@
   gPcAtChipsetPkgTokenSpaceGuid.PcdMaximalValidYear             ## CONSUMES

   gPcAtChipsetPkgTokenSpaceGuid.PcdRtcIndexRegister             ## CONSUMES

   gPcAtChipsetPkgTokenSpaceGuid.PcdRtcTargetRegister            ## CONSUMES

+  gPcAtChipsetPkgTokenSpaceGuid.PcdRtcIndexRegister64           ## CONSUMES

+  gPcAtChipsetPkgTokenSpaceGuid.PcdRtcTargetRegister64          ## CONSUMES

 

 [Depex]

   gEfiVariableArchProtocolGuid AND gEfiVariableWriteArchProtocolGuid