x86: make LOAD_FROM_32_BIT visible for platforms
This option is useful not only for development, but for the platforms
where U-Boot is run from custom ROM bootloader. For example, Intel
Edison is that board.
Make this option visible that platforms can select it if needed.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 675b56f..5f9597b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -195,6 +195,14 @@
depends on X86_RESET_VECTOR
default 0xfffff800
+config X86_LOAD_FROM_32_BIT
+ bool "Boot from a 32-bit program"
+ help
+ Define this to boot U-Boot from a 32-bit program which sets
+ the GDT differently. This can be used to boot directly from
+ any stage of coreboot, for example, bypassing the normal
+ payload-loading feature.
+
config BOARD_ROMSIZE_KB_512
bool
config BOARD_ROMSIZE_KB_1024
diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S
index a5cba1c..8de55a0 100644
--- a/arch/x86/cpu/start.S
+++ b/arch/x86/cpu/start.S
@@ -18,14 +18,6 @@
#include <generated/generic-asm-offsets.h>
#include <generated/asm-offsets.h>
-/*
- * Define this to boot U-Boot from a 32-bit program which sets the GDT
- * differently. This can be used to boot directly from any stage of coreboot,
- * for example, bypassing the normal payload-loading feature.
- * This is only useful for development.
- */
-#undef LOAD_FROM_32_BIT
-
.section .text
.code32
.globl _start
@@ -76,7 +68,7 @@
/* Save table pointer */
movl %ecx, %esi
-#ifdef LOAD_FROM_32_BIT
+#ifdef CONFIG_X86_LOAD_FROM_32_BIT
lgdt gdt_ptr2
#endif
@@ -233,7 +225,7 @@
/* entry addr */
.long CONFIG_SYS_TEXT_BASE
-#ifdef LOAD_FROM_32_BIT
+#ifdef CONFIG_X86_LOAD_FROM_32_BIT
/*
* The following Global Descriptor Table is just enough to get us into
* 'Flat Protected Mode' - It will be discarded as soon as the final