[PATCH 1/5] arch/x86: Add 64-bit U-Boot configuration without SPL

[Jeremy Compostella <jeremy.compostella@intel.com>]

This commit introduces a new configuration option X86_RUN_64BIT_NO_SPL
to allow building U-Boot as a 64-bit binary without using the SPL
(Secondary Program Loader). The motivation is to simplify the boot
process for certain x86-based platforms that do not require SPL, such as
those booting directly from a 64-bit coreboot firmware.

This update revises the `X86_RUN_64BIT` configuration to more accurately
describe its role as "32-bit SPL followed by 64-bit U-Boot." It
clarifies the sequence of operations during the boot process, where the
system transitions from a 32-bit SPL (Secondary Program Loader) to the
main 64-bit U-Boot.

Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 arch/x86/Kconfig              | 10 +++++++++-
 arch/x86/cpu/coreboot/Kconfig |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 006a59d6fa6..dc9483ad723 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -30,7 +30,7 @@ config X86_RUN_32BIT
 	  arch_phys_memset() can be used for basic access to other memory.
 
 config X86_RUN_64BIT
-	bool "64-bit"
+	bool "32-bit SPL followed by 64-bit U-Boot"
 	select X86_64
 	select SPL if !EFI_APP
 	select SPL_SEPARATE_BSS if !EFI_APP
@@ -40,6 +40,14 @@ config X86_RUN_64BIT
 	  runs through the 16-bit and 32-bit init, then switches to 64-bit
 	  mode and jumps to U-Boot proper.
 
+config X86_RUN_64BIT_NO_SPL
+	bool "64-bit"
+	select X86_64
+	help
+          Build U-Boot as a 64-bit binary without SPL. As U-Boot enters
+          in 64-bit mode, the assumption is that the silicon is fully
+          initialized (MP, page tables, etc.).
+
 endchoice
 
 config X86_64
diff --git a/arch/x86/cpu/coreboot/Kconfig b/arch/x86/cpu/coreboot/Kconfig
index 085302c0482..66f25533b97 100644
--- a/arch/x86/cpu/coreboot/Kconfig
+++ b/arch/x86/cpu/coreboot/Kconfig
@@ -26,7 +26,7 @@ config SYS_COREBOOT
 	imply CBMEM_CONSOLE
 	imply X86_TSC_READ_BASE
 	imply USE_PREBOOT
-	select BINMAN if X86_64
+	select BINMAN if X86_RUN_64BIT
 	select SYSINFO
 	imply SYSINFO_EXTRA
 
-- 
2.48.1