efi: Add support for loading U-Boot through an EFI stub
It is useful to be able to load U-Boot onto a board even if is it already
running EFI. This can allow access to the U-Boot command interface, flexible
booting options and easier development.
The easiest way to do this is to build U-Boot as a binary blob and have an
EFI stub copy it into RAM. Add support for this feature, targeting 32-bit
initially.
Also add a way to detect when U-Boot has been loaded via a stub. This goes
in common.h since it needs to be widely available so that we avoid redoing
initialisation that should be skipped.
Signed-off-by: Simon Glass <sjg@chromium.org>
Improvements to how the payload is built:
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/common.h b/include/common.h
index 4566bd1..fcc9ae7 100644
--- a/include/common.h
+++ b/include/common.h
@@ -1021,6 +1021,13 @@
offsetof(struct structure, member) == offset, \
"`struct " #structure "` offset for `" #member "` is not " #offset)
+/* Avoid using CONFIG_EFI_STUB directly as we may boot from other loaders */
+#ifdef CONFIG_EFI_STUB
+#define ll_boot_init() false
+#else
+#define ll_boot_init() true
+#endif
+
/* Pull in stuff for the build system */
#ifdef DO_DEPS_ONLY
# include <environment.h>
diff --git a/include/efi.h b/include/efi.h
index f009701..1470c08 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -268,11 +268,15 @@
/* Base address of the EFI image */
extern char image_base[];
+/* Start and end of U-Boot image (for payload) */
+extern char _binary_u_boot_dtb_bin_start[], _binary_u_boot_dtb_bin_end[];
+
/**
* efi_get_sys_table() - Get access to the main EFI system table
*
* @return pointer to EFI system table
*/
+
struct efi_system_table *efi_get_sys_table(void);
/**