boot/edk2: allow building for i386

Add support the build the firmware for QEMU i386 pc machine

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
[yann.morin.1998@free.fr:
  - do not make it available for BR2_x86_64
  - introduce BR2_TARGET_EDK2_ARCH_SUPPORTS
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

boot/edk2/Config.in

@@ -1,6 +1,12 @@
+config BR2_TARGET_EDK2_ARCH_SUPPORTS
+	bool
+	default y if BR2_aarch64
+	default y if BR2_i386
+	default y if BR2_x86_64
+
 config BR2_TARGET_EDK2
 	bool "EDK2"
-	depends on BR2_x86_64 || BR2_aarch64
+	depends on BR2_TARGET_EDK2_ARCH_SUPPORTS
 	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_5
 	select BR2_PACKAGE_EDK2_PLATFORMS
 	help
@@ -13,9 +19,18 @@ if BR2_TARGET_EDK2
 
 choice
 	prompt "Platform"
+	default BR2_TARGET_EDK2_PLATFORM_OVMF_I386 if BR2_i386
 	default BR2_TARGET_EDK2_PLATFORM_OVMF_X64 if BR2_x86_64
 	default BR2_TARGET_EDK2_PLATFORM_ARM_VIRT_QEMU if BR2_aarch64
 
+config BR2_TARGET_EDK2_PLATFORM_OVMF_I386
+	bool "i386"
+	depends on BR2_i386
+	help
+	  Platform configuration for a generic i386 target.
+	  This platform will boot from flash address 0x0.
+	  It should therefore be used as the first bootloader.
+
 config BR2_TARGET_EDK2_PLATFORM_OVMF_X64
 	bool "x86-64"
 	depends on BR2_x86_64
@@ -94,6 +109,7 @@ endchoice
 
 config BR2_TARGET_EDK2_FD_NAME
 	string
+	default "OVMF" if BR2_TARGET_EDK2_PLATFORM_OVMF_I386
 	default "OVMF" if BR2_TARGET_EDK2_PLATFORM_OVMF_X64
 	default "QEMU_EFI" if BR2_TARGET_EDK2_PLATFORM_ARM_VIRT_QEMU
 	default "QEMU_EFI" if BR2_TARGET_EDK2_PLATFORM_ARM_VIRT_QEMU_KERNEL

boot/edk2/edk2.mk

@@ -14,7 +14,9 @@ EDK2_DEPENDENCIES = edk2-platforms host-python3 host-acpica host-util-linux
 EDK2_INSTALL_TARGET = NO
 EDK2_INSTALL_IMAGES = YES
 
-ifeq ($(BR2_x86_64),y)
+ifeq ($(BR2_i386),y)
+EDK2_ARCH = IA32
+else ifeq ($(BR2_x86_64),y)
 EDK2_ARCH = X64
 else ifeq ($(BR2_aarch64),y)
 EDK2_ARCH = AARCH64
@@ -55,7 +57,13 @@ EDK2_GIT_SUBMODULES = YES
 EDK2_BUILD_PACKAGES = $(@D)/Build/Buildroot
 EDK2_PACKAGES_PATH = $(@D):$(EDK2_BUILD_PACKAGES):$(STAGING_DIR)/usr/share/edk2-platforms
 
-ifeq ($(BR2_TARGET_EDK2_PLATFORM_OVMF_X64),y)
+ifeq ($(BR2_TARGET_EDK2_PLATFORM_OVMF_I386),y)
+EDK2_DEPENDENCIES += host-nasm
+EDK2_PACKAGE_NAME = OvmfPkg
+EDK2_PLATFORM_NAME = OvmfPkgIa32
+EDK2_BUILD_DIR = OvmfIa32
+
+else ifeq ($(BR2_TARGET_EDK2_PLATFORM_OVMF_X64),y)
 EDK2_DEPENDENCIES += host-nasm
 EDK2_PACKAGE_NAME = OvmfPkg
 EDK2_PLATFORM_NAME = OvmfPkgX64