x86: Support QEMU x86 targets

This commit introduces the initial U-Boot support for QEMU x86 targets.
U-Boot can boot from coreboot as a payload, or directly without coreboot.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Merged in patch 'x86: qemu: Add CMD_NET to qemu-x86_defconfig
   https://patchwork.ozlabs.org/patch/479745/

board/emulation/Kconfig

@@ -0,0 +1,25 @@
+#
+# Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+if VENDOR_EMULATION
+
+choice
+	prompt "Mainboard model"
+
+config TARGET_QEMU_X86
+	bool "QEMU x86"
+	help
+	  This is the QEMU emulated x86 board. U-Boot supports running
+	  as a coreboot payload as well as bare boot without coreboot.
+	  There are two types of x86 boards supported by QEMU which are
+	  supported by U-Boot. They are via QEMU '-M pc', an i440FX/PIIX
+	  chipset platform and '-M q35', a Q35/ICH9 chipset platform.
+
+endchoice
+
+source "board/emulation/qemu-x86/Kconfig"
+
+endif

board/emulation/qemu-x86/Kconfig

@@ -0,0 +1,24 @@
+if TARGET_QEMU_X86
+
+config SYS_BOARD
+	default "qemu-x86"
+
+config SYS_VENDOR
+	default "emulation"
+
+config SYS_SOC
+	default "qemu"
+
+config SYS_CONFIG_NAME
+	default "qemu-x86"
+
+config SYS_TEXT_BASE
+	default 0xfff00000
+
+config BOARD_SPECIFIC_OPTIONS # dummy
+	def_bool y
+	select X86_RESET_VECTOR
+	select QEMU
+	select BOARD_ROMSIZE_KB_1024
+
+endif

board/emulation/qemu-x86/MAINTAINERS

@@ -0,0 +1,6 @@
+QEMU X86 BOARD
+M:	Bin Meng <bmeng.cn@gmail.com>
+S:	Maintained
+F:	board/emulation/qemu-x86/
+F:	include/configs/qemu-x86.h
+F:	configs/qemu-x86_defconfig

board/emulation/qemu-x86/Makefile

@@ -0,0 +1,7 @@
+#
+# Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-y	+= qemu-x86.o start.o

board/emulation/qemu-x86/qemu-x86.c

@@ -0,0 +1,13 @@
+/*
+ * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <netdev.h>
+
+int board_eth_init(bd_t *bis)
+{
+	return pci_eth_init(bis);
+}

board/emulation/qemu-x86/start.S

@@ -0,0 +1,9 @@
+/*
+ * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+.globl early_board_init
+early_board_init:
+	jmp	early_board_init_ret