On Fri, Mar 17, 2017 at 09:47:24PM +0100, Laszlo Ersek wrote:
> The presence of this protocol in the DXE protocol database implies that
> the platform provides the operating system with an ACPI-based hardware
> description. This is not necessarily mutually exclusive with a Device
> Tree-based hardware description. A platform driver is supposed to produce
> a single instance of the protocol (with NULL contents), if appropriate.
>
> The decision to produce the protocol is platform specific; for example, it
> could depend on an HII checkbox / underlying non-volatile UEFI variable.
>
> The protocol is meant to be consumed by
> "MdeModulePkg/Universal/Acpi/AcpiTableDxe", through the
> PlatformHasAcpiLib plug-in. By linking this library into AcpiTableDxe via
> NULL resolution in the platform DSC, the platform makes
> EFI_ACPI_TABLE_PROTOCOL and (if enabled) EFI_ACPI_SDT_PROTOCOL dependent
> on the above dynamic decision.
>
> In turn, other (platform and universal) DXE drivers that produce ACPI
> tables will wait for EFI_ACPI_TABLE_PROTOCOL / EFI_ACPI_SDT_PROTOCOL, via
> DEPEX, protocol notify, or a simple gBS->LocateProtocol() in a "late
> enough" callback (such as Ready To Boot).
>
> Because this protocol is not standard, it is prefixed with EDKII / Edkii,
> as seen elsewhere in MdeModulePkg and SecurityPkg, for example. (ARM / Arm
> doesn't look future-proof enough; future UEFI platforms could face the
> same issue.) In addition, an effort is made to avoid the phrase
> "AcpiPlatform", as that belongs to drivers / libraries that produce
> platform specific ACPI content (as opposed to deciding whether the entire
> firmware will have access to EFI_ACPI_TABLE_PROTOCOL).
I greatly approve, but since you've already done this generically - is
there any good reason to keep this in ArmPkg?
I am strongly looking to get rid of "things that happen to have been
implemented for ARM" from there and pruning it down to contain only
things that are architecturelly ARM-specific.
MdeModulePkg?
Regards,
Leif
> Cc: Ard Biesheuvel <ard.biesheu...@linaro.org>
> Cc: Leif Lindholm <leif.lindh...@linaro.org>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Laszlo Ersek <ler...@redhat.com>
> ---
> ArmPkg/ArmPkg.dec | 4 ++
> ArmPkg/Library/PlatformHasAcpiLib/PlatformHasAcpiLib.inf | 40
> ++++++++++++++++++++
> ArmPkg/Include/Protocol/PlatformHasAcpi.h | 34
> +++++++++++++++++
> ArmPkg/Library/PlatformHasAcpiLib/PlatformHasAcpiLib.c | 36
> ++++++++++++++++++
> 4 files changed, 114 insertions(+)
>
> diff --git a/ArmPkg/ArmPkg.dec b/ArmPkg/ArmPkg.dec
> index c4b4da2f95bb..0e49360a386a 100644
> --- a/ArmPkg/ArmPkg.dec
> +++ b/ArmPkg/ArmPkg.dec
> @@ -52,6 +52,10 @@ [Ppis]
> ## Include/Ppi/ArmMpCoreInfo.h
> gArmMpCoreInfoPpiGuid = { 0x6847cc74, 0xe9ec, 0x4f8f, {0xa2, 0x9d, 0xab,
> 0x44, 0xe7, 0x54, 0xa8, 0xfc} }
>
> +[Protocols]
> + ## Include/Protocol/PlatformHasAcpi.h
> + gEdkiiPlatformHasAcpiProtocolGuid = { 0xf0966b41, 0xc23f, 0x41b9, {
> 0x96, 0x04, 0x0f, 0xf7, 0xe1, 0x11, 0x96, 0x5a } }
> +
> [PcdsFeatureFlag.common]
> gArmTokenSpaceGuid.PcdCpuDxeProduceDebugSupport|FALSE|BOOLEAN|0x00000001
>
> diff --git a/ArmPkg/Library/PlatformHasAcpiLib/PlatformHasAcpiLib.inf
> b/ArmPkg/Library/PlatformHasAcpiLib/PlatformHasAcpiLib.inf
> new file mode 100644
> index 000000000000..c83da4d8e98a
> --- /dev/null
> +++ b/ArmPkg/Library/PlatformHasAcpiLib/PlatformHasAcpiLib.inf
> @@ -0,0 +1,40 @@
> +## @file
> +# A hook-in library for MdeModulePkg/Universal/Acpi/AcpiTableDxe.
> +#
> +# Plugging this library instance into AcpiTableDxe makes
> +# EFI_ACPI_TABLE_PROTOCOL and (if enabled) EFI_ACPI_SDT_PROTOCOL depend on
> the
> +# platform's dynamic decision whether to expose an ACPI-based hardware
> +# description to the operating system.
> +#
> +# Universal and platform specific DXE drivers that produce ACPI tables depend
> +# on EFI_ACPI_TABLE_PROTOCOL / EFI_ACPI_SDT_PROTOCOL in turn.
> +#
> +# Copyright (C) 2017, Red Hat, Inc.
> +#
> +# 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
> +# http://opensource.org/licenses/bsd-license.php
> +#
> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> WITHOUT
> +# WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +##
> +
> +[Defines]
> + INF_VERSION = 1.25
> + BASE_NAME = PlatformHasAcpiLib
> + FILE_GUID = 29beb028-0958-447b-be0a-12229235d77d
> + MODULE_TYPE = BASE
> + VERSION_STRING = 1.0
> + LIBRARY_CLASS = PlatformHasAcpiLib|DXE_DRIVER
> + CONSTRUCTOR = PlatformHasAcpiInitialize
> +
> +[Sources]
> + PlatformHasAcpiLib.c
> +
> +[Packages]
> + ArmPkg/ArmPkg.dec
> + MdePkg/MdePkg.dec
> +
> +[Depex]
> + gEdkiiPlatformHasAcpiProtocolGuid
> diff --git a/ArmPkg/Include/Protocol/PlatformHasAcpi.h
> b/ArmPkg/Include/Protocol/PlatformHasAcpi.h
> new file mode 100644
> index 000000000000..3cd0cfe4515d
> --- /dev/null
> +++ b/ArmPkg/Include/Protocol/PlatformHasAcpi.h
> @@ -0,0 +1,34 @@
> +/** @file
> + EDKII Platform Has ACPI Protocol
> +
> + The presence of this protocol in the DXE protocol database implies that the
> + platform provides the operating system with an ACPI-based hardware
> + description. Note that this is not necessarily mutually exclusive with a
> + Device Tree-based hardware description. A platform driver is supposed to
> + produce a single instance of the protocol (with NULL contents), if
> + appropriate.
> +
> + Copyright (C) 2017, Red Hat, Inc.
> +
> + This program and the accompanying materials are licensed and made available
> + under the terms and conditions of the BSD License that accompanies this
> + distribution. The full text of the license may be found at
> + http://opensource.org/licenses/bsd-license.php.
> +
> + THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> WITHOUT
> + WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +**/
> +
> +
> +#ifndef __EDKII_PLATFORM_HAS_ACPI_PROTOCOL_H__
> +#define __EDKII_PLATFORM_HAS_ACPI_PROTOCOL_H__
> +
> +#define EDKII_PLATFORM_HAS_ACPI_PROTOCOL_GUID \
> + { \
> + 0xf0966b41, 0xc23f, 0x41b9, \
> + { 0x96, 0x04, 0x0f, 0xf7, 0xe1, 0x11, 0x96, 0x5a } \
> + }
> +
> +extern EFI_GUID gEdkiiPlatformHasAcpiProtocolGuid;
> +
> +#endif
> diff --git a/ArmPkg/Library/PlatformHasAcpiLib/PlatformHasAcpiLib.c
> b/ArmPkg/Library/PlatformHasAcpiLib/PlatformHasAcpiLib.c
> new file mode 100644
> index 000000000000..79072da21c2b
> --- /dev/null
> +++ b/ArmPkg/Library/PlatformHasAcpiLib/PlatformHasAcpiLib.c
> @@ -0,0 +1,36 @@
> +/** @file
> + A hook-in library for MdeModulePkg/Universal/Acpi/AcpiTableDxe.
> +
> + Plugging this library instance into AcpiTableDxe makes
> + EFI_ACPI_TABLE_PROTOCOL and (if enabled) EFI_ACPI_SDT_PROTOCOL depend on
> the
> + platform's dynamic decision whether to expose an ACPI-based hardware
> + description to the operating system.
> +
> + Universal and platform specific DXE drivers that produce ACPI tables depend
> + on EFI_ACPI_TABLE_PROTOCOL / EFI_ACPI_SDT_PROTOCOL in turn.
> +
> + Copyright (C) 2017, Red Hat, Inc.
> +
> + 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
> + http://opensource.org/licenses/bsd-license.php
> +
> + THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> WITHOUT
> + WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> +**/
> +
> +#include <Base.h>
> +
> +RETURN_STATUS
> +EFIAPI
> +PlatformHasAcpiInitialize (
> + VOID
> + )
> +{
> + //
> + // Do nothing, just imbue AcpiTableDxe with an
> + // EDKII_PLATFORM_HAS_ACPI_PROTOCOL dependency.
> + //
> + return RETURN_SUCCESS;
> +}
> --
> 2.9.3
>
>
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