The presence of this GUID in the PPI database, and/or in the DXE protocol
database (as dictated by the platform's needs in these firmware phases)
implies that the platform provides the operating system with an ACPI-based
hardware description. This is not necessarily exclusive with other types
of hardware description (for example, a Device Tree-based one).
A platform PEIM and/or DXE driver is supposed to produce a single instance
of the PPI and/or protocol (with NULL contents), if appropriate. The
decision to produce the PPI and/or protocol is platform specific; for
example, in the DXE phase, it could depend on an HII checkbox / underlying
non-volatile UEFI variable.
In the DXE phase, the protocol is meant to be depended-upon by
"MdeModulePkg/Universal/Acpi/AcpiTableDxe", indirectly:
* In the long term, interested platforms will establish this dependency by
hooking an (upcoming) NULL-class DepexLib instance into AcpiTableDxe in
their DSC files, pointing DepexLib's DEPEX through a FixedAtBuild PCD to
the GUID introduced here. (For the prerequisite BaseTools feature, refer
to <https://bugzilla.tianocore.org/show_bug.cgi?id=443>).
* In the short term, an interested platform may hook a private NULL-class
library instance (called e.g. "PlatformHasAcpiLib") into AcpiTableDxe.
Such a library instance would be a specialization of the above described
generic DepexLib, with the DEPEX open-coded on the GUID introduced here.
Either way, the platform makes EFI_ACPI_TABLE_PROTOCOL and (if enabled)
EFI_ACPI_SDT_PROTOCOL dependent on the platform's dynamic decision to
produce or not to produce a NULL protocol instance with this GUID.
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 GUID is not standard, it is prefixed with EDKII / Edkii, as
seen elsewhere in MdeModulePkg and SecurityPkg. 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, or any similar facilities in the PEI phase).
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Instead of using a dynamic PCD, store the device tree address in a HOB
so that we can also run under a configuration that does not support
dynamic PCDs.
This also adds MemoryAllocationLib to the [LibraryClasses] section of
ArmVirtualizationPlatformLib/ArmVirtualizationPlatformLib.inf, as this
dependency was formerly satisfied transitively through one of the
library dependencies that were dropped.
Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Olivier Martin <olivier.martin@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16959 6f19259b-4bc3-4df7-8a09-765794883524
The FdtPlatformDxe driver installs the FDT of the platform it
is running on into the UEFI Configuration table at the end of
the DXE phase.
Please refer to the README.txt file for a global overview of
the driver.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ronald Cron <Ronald.Cron@arm.com>
Reviewed-by: Olivier Martin <olivier.martin@arm.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16933 6f19259b-4bc3-4df7-8a09-765794883524
