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PcAtChipsetPkg: Add MMIO Support to RTC driver

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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>
This commit is contained in:
Sami Mujawar
2020-10-02 22:13:55 +01:00
committed by mergify[bot]
parent a7d977040b
commit 015be4075f
4 changed files with 187 additions and 13 deletions
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16
PcAtChipsetPkg/PcAtChipsetPkg.dec
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@@ -6,6 +6,7 @@
#
# Copyright (c) 2009 - 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
#
@@ -41,6 +42,13 @@
# @Prompt Configure HPET to use MSI.
gPcAtChipsetPkgTokenSpaceGuid.PcdHpetMsiEnable|TRUE|BOOLEAN|0x00001000
## Indicates the RTC port registers are in MMIO space, or in I/O space.
# Default is I/O space.<BR><BR>
# TRUE - RTC port registers are in MMIO space.<BR>
# FALSE - RTC port registers are in I/O space.<BR>
# @Prompt RTC port registers use MMIO.
gPcAtChipsetPkgTokenSpaceGuid.PcdRtcUseMmio|FALSE|BOOLEAN|0x00000021
[PcdsFixedAtBuild, PcdsDynamic, PcdsDynamicEx, PcdsPatchableInModule]
## This PCD specifies the base address of the HPET timer.
# @Prompt HPET base address.
@@ -68,6 +76,14 @@
# @Expression 0x80000001 | gPcAtChipsetPkgTokenSpaceGuid.PcdMaximalValidYear < gPcAtChipsetPkgTokenSpaceGuid.PcdMinimalValidYear + 100
gPcAtChipsetPkgTokenSpaceGuid.PcdMaximalValidYear|2097|UINT16|0x0000000E
## Specifies RTC Index Register address in MMIO space.
# @Prompt RTC Index Register address
gPcAtChipsetPkgTokenSpaceGuid.PcdRtcIndexRegister64|0x0|UINT64|0x00000022
## Specifies RTC Target Register address in MMIO space.
# @Prompt RTC Target Register address
gPcAtChipsetPkgTokenSpaceGuid.PcdRtcTargetRegister64|0x0|UINT64|0x00000023
[PcdsFixedAtBuild, PcdsPatchableInModule]
## Defines the ACPI register set base address.
# The invalid 0xFFFF is as its default value. It must be configured to the real value.