[U-Boot] [PATCH v3 1/1] x86: provide CONFIG_BUILD_ROM

[Heinrich Schuchardt]

Up to now we depended on an exported variable to build u-boot.rom.
We should be able to specify it in the configuration file, too.

With this patch this becomes possible using the new Kconfig option
CONFIG_BUILD_ROM.

This option depends on CONFIG_X86 and is selected in
qemu-x86_defconfig and qemu-x86_64_defconfig.

Cc: Simon Glass <sjg at chromium.org>
Cc: Bin Meng <bmeng.cn at gmail.com>
Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
v3
	Rework the documentation. Simon suggested not to deprecate
	the export variable.
v2
	Enable CONFIG_BUILD_ROM for qemu-x86_64_defconfig
	as suggested by Bin.
	Fix typos.
---
 Kconfig                       | 10 ++++++++++
 Makefile                      |  2 +-
 configs/qemu-x86_64_defconfig |  1 +
 configs/qemu-x86_defconfig    |  1 +
 doc/README.x86                | 10 +++++++---
 5 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/Kconfig b/Kconfig
index d951e9f804..70508591fd 100644
--- a/Kconfig
+++ b/Kconfig
@@ -158,6 +158,16 @@ config PHYS_64BIT
 	  This can be used not only for 64bit SoCs, but also for
 	  large physical address extention on 32bit SoCs.
 
+config BUILD_ROM
+	bool "Build U-Boot as BIOS replacement"
+	depends on X86
+	default n
+	help
+	  This option allows to build a ROM version of U-Boot.
+	  The build process generally requires several binary blobs
+	  which are not shipped in the U-Boot source tree.
+	  Please, see doc/README.x86 for details.
+
 endmenu		# General setup
 
 menu "Boot images"
diff --git a/Makefile b/Makefile
index 888486b296..f26ab77f6a 100644
--- a/Makefile
+++ b/Makefile
@@ -796,7 +796,7 @@ ALL-$(CONFIG_REMAKE_ELF) += u-boot.elf
 ALL-$(CONFIG_EFI_APP) += u-boot-app.efi
 ALL-$(CONFIG_EFI_STUB) += u-boot-payload.efi
 
-ifneq ($(BUILD_ROM),)
+ifneq ($(BUILD_ROM)$(CONFIG_BUILD_ROM),)
 ALL-$(CONFIG_X86_RESET_VECTOR) += u-boot.rom
 endif
 
diff --git a/configs/qemu-x86_64_defconfig b/configs/qemu-x86_64_defconfig
index 071dca6eee..c3a97cbdda 100644
--- a/configs/qemu-x86_64_defconfig
+++ b/configs/qemu-x86_64_defconfig
@@ -1,4 +1,5 @@
 CONFIG_X86=y
+CONFIG_BUILD_ROM=y
 CONFIG_SPL_LIBCOMMON_SUPPORT=y
 CONFIG_SPL_LIBGENERIC_SUPPORT=y
 CONFIG_SYS_MALLOC_F_LEN=0x1000
diff --git a/configs/qemu-x86_defconfig b/configs/qemu-x86_defconfig
index cdbc5c4a6e..e4a3e31ad5 100644
--- a/configs/qemu-x86_defconfig
+++ b/configs/qemu-x86_defconfig
@@ -1,4 +1,5 @@
 CONFIG_X86=y
+CONFIG_BUILD_ROM=y
 CONFIG_MAX_CPUS=2
 CONFIG_DEFAULT_DEVICE_TREE="qemu-x86_i440fx"
 CONFIG_SMP=y
diff --git a/doc/README.x86 b/doc/README.x86
index c96a22cb08..1e3af5af90 100644
--- a/doc/README.x86
+++ b/doc/README.x86
@@ -80,11 +80,15 @@ Building a ROM version of U-Boot (hereafter referred to as u-boot.rom) is a
 little bit tricky, as generally it requires several binary blobs which are not
 shipped in the U-Boot source tree. Due to this reason, the u-boot.rom build is
 not turned on by default in the U-Boot source tree. Firstly, you need turn it
-on by enabling the ROM build:
+on by enabling the ROM build either via an environment variable
 
-$ export BUILD_ROM=y
+    $ export BUILD_ROM=y
 
-This tells the Makefile to build u-boot.rom as a target.
+or via configuration
+
+    CONFIG_BUILD_ROM=y
+
+Both tell the Makefile to build u-boot.rom as a target.
 
 ---
 
-- 
2.14.1