efi: Add start-up library code

When running as an EFI application, U-Boot must request memory from EFI,
and provide access to the boot services U-Boot needs.

Add library code to perform these tasks. This includes efi_main() which is
the entry point from EFI. U-Boot is built as a shared library.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/lib/efi/Kconfig b/lib/efi/Kconfig
new file mode 100644
index 0000000000..b23ba5b504
--- /dev/null
+++ b/lib/efi/Kconfig
@@ -0,0 +1,33 @@
+config EFI
+	bool "Support running U-Boot from EFI"
+	depends on X86
+	help
+	  U-Boot can be started from EFI on certain platforms. This allows
+	  EFI to perform most of the system init and then jump to U-Boot for
+	  final system boot. Another option is to run U-Boot as an EFI
+	  application, with U-Boot using EFI's drivers instead of its own.
+
+choice
+	prompt "Select EFI mode to use"
+	depends on X86 && EFI
+
+config EFI_APP
+	bool "Support running as an EFI application"
+	help
+	  Build U-Boot as an application which can be started from EFI. This
+	  is useful for examining a platform in the early stages of porting
+	  U-Boot to it. It allows only very basic functionality, such as a
+	  command prompt and memory and I/O functions. Use 'reset' to return
+	  to EFI.
+
+config EFI_RAM_SIZE
+	hex "Amount of EFI RAM for U-Boot"
+	depends on EFI_APP
+	default 0x2000000
+	help
+	  Set the amount of EFI RAM which is claimed by U-Boot for its own
+	  use. U-Boot allocates this from EFI on start-up (along with a few
+	  other smaller amounts) and it can never be increased after that.
+	  It is used as the RAM size in with U-Boot.
+
+endchoice