Unlike Linux on x86, which typically honors the PCI configuration performed
by the firmware, Linux on ARM assumes that the PCI subsystem needs to be
configured from scratch. This is not entirely unreasonable given the
historical background of embedded systems using very basic bootloaders,
but is no longer tenable with Linux on arm64 moving to UEFI and ACPI in the
server space. For this reason, PCI support in the arm64 kernel running under
ACPI is likely to move to the x86 model of honoring the PCI configuration
done by the firmware.
So let's align with that in our DT based configuration as well, and set the
/chosen/linux,pci-probe-only property to 1 in the Device Tree before we
hand it to the OS.
In case we are exposing an emulated VGA PCI device to the guest, which may
subsequently get exposed via the Graphics Output protocol and driven as an
efifb by the OS, this ensures the PCI resource allocations for the framebuffer
are not overridden, since that would cause the framebuffer to stop working.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
A DMA-like transfer interface has recently been implemented in QEMU for
fw-cfg. For ARM and AARCH64 virtual machines, the binding prescribes a new
8-byte wide register at offset 0x10 in the register block. Make VirtFdtDxe
expose this register if it is present.
Please see "docs/specs/fw_cfg.txt" in the QEMU tree for more information.
Cc: Ard Biesheuvel <ard.biesheuvel@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>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18544 6f19259b-4bc3-4df7-8a09-765794883524
In order to allow a ArmGicArchLib to be implemented that returns
the supported GIC revision based on the device tree, add handling
to VirtFdtDxe to record the GIC revision at DT parsing time.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18101 6f19259b-4bc3-4df7-8a09-765794883524
Ard Biesheuvel
Laszlo Ersek
Olivier Martin