x86: Add generic EFI payload support

It is possible to create a generic EFI payload for all x86 boards.
The payload is configured to include as many generic drivers as
possible. All stuff that touches low-level initialization are not
allowed as such is the EFI BIOS's responsibility. Platform specific
drivers (like gpio, spi, etc) are not included.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/board/efi/Kconfig b/board/efi/Kconfig
index 6f86a48..d37f6ff 100644
--- a/board/efi/Kconfig
+++ b/board/efi/Kconfig
@@ -12,8 +12,17 @@
 	  takes over once the RAM, video and CPU are fully running.
 	  U-Boot is loaded as an application from EFI.
 
+config TARGET_EFI_PAYLOAD
+	bool "efi payload"
+	help
+	  This target is used for running U-Boot on top of EFI. In
+	  this case EFI does the early initialisation, and U-Boot
+	  takes over once the RAM, video and CPU are fully running.
+	  U-Boot is loaded as a payload from EFI.
+
 endchoice
 
 source "board/efi/efi-x86/Kconfig"
+source "board/efi/efi-x86_payload/Kconfig"
 
 endif
diff --git a/board/efi/efi-x86_payload/Kconfig b/board/efi/efi-x86_payload/Kconfig
new file mode 100644
index 0000000..dcf4de8
--- /dev/null
+++ b/board/efi/efi-x86_payload/Kconfig
@@ -0,0 +1,38 @@
+if TARGET_EFI_PAYLOAD
+
+config SYS_BOARD
+	default "efi-x86_payload"
+
+config SYS_VENDOR
+	default "efi"
+
+config SYS_SOC
+	default "efi"
+
+config SYS_CONFIG_NAME
+	default "efi-x86_payload"
+
+config SYS_TEXT_BASE
+	default 0x00200000
+
+config BOARD_SPECIFIC_OPTIONS # dummy
+	def_bool y
+	imply SYS_NS16550
+	imply SCSI
+	imply SCSI_AHCI
+	imply AHCI_PCI
+	imply MMC
+	imply MMC_PCI
+	imply MMC_SDHCI
+	imply MMC_SDHCI_SDMA
+	imply USB
+	imply USB_EHCI_HCD
+	imply USB_XHCI_HCD
+	imply USB_STORAGE
+	imply USB_KEYBOARD
+	imply E1000
+	imply ETH_DESIGNWARE
+	imply PCH_GBE
+	imply RTL8169
+
+endif
diff --git a/board/efi/efi-x86_payload/MAINTAINERS b/board/efi/efi-x86_payload/MAINTAINERS
new file mode 100644
index 0000000..abf3a15
--- /dev/null
+++ b/board/efi/efi-x86_payload/MAINTAINERS
@@ -0,0 +1,7 @@
+EFI-X86_PAYLOAD BOARD
+M:	Bin Meng <bmeng.cn@gmail.com>
+S:	Maintained
+F:	board/efi/efi-x86_payload/
+F:	include/configs/efi-x86_payload.h
+F:	configs/efi-x86_payload32_defconfig
+F:	configs/efi-x86_payload64_defconfig
diff --git a/board/efi/efi-x86_payload/Makefile b/board/efi/efi-x86_payload/Makefile
new file mode 100644
index 0000000..6982340
--- /dev/null
+++ b/board/efi/efi-x86_payload/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+
+obj-y	+= start.o
diff --git a/board/efi/efi-x86_payload/start.S b/board/efi/efi-x86_payload/start.S
new file mode 100644
index 0000000..f7eaa7c
--- /dev/null
+++ b/board/efi/efi-x86_payload/start.S
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+.globl early_board_init
+early_board_init:
+	jmp	early_board_init_ret