payload/external/edk2: Add Kconfig to support use of PCIe OpROMs

Add a Kconfig to support passing `LOAD_OPTION_ROMS=TRUE` as a build
parameter in order to enable edk2 support for dGPUs.

Change-Id: I05444425d1cb98b023681639389949bf3f3b8e9c
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/87407
Reviewed-by: Frans Hendriks <fhendriks@eltan.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Sean Rhodes <sean@starlabs.systems>
Reviewed-by: Alicja Michalska <ahplka19@gmail.com>

payloads/external/Makefile.mk

@@ -182,6 +182,7 @@ $(obj)/UEFIPAYLOAD.fd: $(DOTCONFIG)
 		CONFIG_EDK2_FULL_SCREEN_SETUP=$(CONFIG_EDK2_FULL_SCREEN_SETUP) \
 		CONFIG_EDK2_HAVE_EFI_SHELL=$(CONFIG_EDK2_HAVE_EFI_SHELL) \
 		CONFIG_EDK2_PRIORITIZE_INTERNAL=$(CONFIG_EDK2_PRIORITIZE_INTERNAL) \
+		CONFIG_EDK2_LOAD_OPTION_ROMS=$(CONFIG_EDK2_LOAD_OPTION_ROMS) \
 		CONFIG_EDK2_PS2_SUPPORT=$(CONFIG_EDK2_PS2_SUPPORT) \
 		CONFIG_EDK2_SERIAL_SUPPORT=$(CONFIG_EDK2_SERIAL_SUPPORT) \
 		CONFIG_EDK2_SD_MMC_TIMEOUT=$(CONFIG_EDK2_SD_MMC_TIMEOUT) \

payloads/external/edk2/Kconfig

@@ -240,6 +240,14 @@ config EDK2_PRIORITIZE_INTERNAL
 	help
 	  Prioritize internal boot devices over external devices
 
+config EDK2_LOAD_OPTION_ROMS
+	bool "Load and Execute OpROMs on PCIe devices"
+	depends on EDK2_REPO_MRCHROMEBOX
+	default n
+	help
+	  Load and execute OpROMs on PCIe devices.
+	  Select this option to support use of an external dGPU.
+
 config EDK2_PS2_SUPPORT
 	bool "Support PS/2 Keyboards"
 	default y

payloads/external/edk2/Makefile

@@ -149,6 +149,10 @@ endif
 ifeq ($(CONFIG_EDK2_USE_LAPIC_TIMER),y)
 BUILD_STR += -D TIMER_SUPPORT=LAPIC
 endif
+# LOAD_OPTION_ROMS		= FALSE
+ifeq ($(CONFIG_EDK2_LOAD_OPTION_ROMS),y)
+BUILD_STR += -D LOAD_OPTION_ROMS=TRUE
+endif
 
 endif