[PATCH v3 3/5] spl: fit: enable signing a generated u-boot.itb

[Heiko Stuebner]

From: Heiko Stuebner <heiko.stuebner at theobroma-systems.com>

With SPL_FIT_SIGNATURE enabled we will likely want a generated
u-boot.itb to be signed and the key stores so that the spl can
reach it.

So add a SPL_FIT_SIGNATURE_KEY_DIR option and suitable hooks
into the Makefile to have mkimage sign the .itb and store the
used key into the spl dtb file.

The added dependencies should make sure that the u-boot.itb
gets generated before the spl-binary gets build, so that there
is the necessary space for the key to get included.

Signed-off-by: Heiko Stuebner <heiko.stuebner at theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
---
changes in v2.1:
- depend on $(CONFIG_SPL_FIT_SIGNATURE)$(U_BOOT_ITS)
  instead of only $(CONFIG_SPL_FIT_GENERATOR)

 Kconfig  |  8 ++++++++
 Makefile | 11 ++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/Kconfig b/Kconfig
index 0c184f7f06..bab7c4f3ee 100644
--- a/Kconfig
+++ b/Kconfig
@@ -465,6 +465,14 @@ config SPL_FIT_SIGNATURE
 	select SPL_RSA_VERIFY
 	select SPL_IMAGE_SIGN_INFO
 
+config SPL_FIT_SIGNATURE_KEY_DIR
+	string "key directory for signing U-Boot FIT image"
+	depends on SPL_FIT_SIGNATURE
+	default "keys"
+	help
+	  The directory to give to mkimage to retrieve keys from when
+	  generating a signed U-Boot FIT image.
+
 config SPL_LOAD_FIT
 	bool "Enable SPL loading U-Boot as a FIT (basic fitImage features)"
 	select SPL_FIT
diff --git a/Makefile b/Makefile
index 463fa72e3f..b8f7536940 100644
--- a/Makefile
+++ b/Makefile
@@ -1407,6 +1407,14 @@ MKIMAGEFLAGS_u-boot.itb =
 else
 MKIMAGEFLAGS_u-boot.itb = -E
 endif
+ifdef CONFIG_SPL_FIT_SIGNATURE
+ifdef CONFIG_SPL_OF_CONTROL
+MKIMAGEFLAGS_u-boot.itb += -K dts/dt-spl.dtb -r
+ifneq ($(CONFIG_SPL_FIT_SIGNATURE_KEY_DIR),"")
+MKIMAGEFLAGS_u-boot.itb += -k $(CONFIG_SPL_FIT_SIGNATURE_KEY_DIR)
+endif
+endif
+endif
 
 u-boot.itb: u-boot-nodtb.bin \
 		$(if $(CONFIG_OF_SEPARATE)$(CONFIG_OF_EMBED)$(CONFIG_OF_HOSTFILE),dts/dt.dtb) \
@@ -1929,7 +1937,8 @@ spl/u-boot-spl.bin: spl/u-boot-spl
 
 spl/u-boot-spl: tools prepare \
 		$(if $(CONFIG_OF_SEPARATE)$(CONFIG_OF_EMBED)$(CONFIG_SPL_OF_PLATDATA),dts/dt.dtb) \
-		$(if $(CONFIG_OF_SEPARATE)$(CONFIG_OF_EMBED)$(CONFIG_TPL_OF_PLATDATA),dts/dt.dtb)
+		$(if $(CONFIG_OF_SEPARATE)$(CONFIG_OF_EMBED)$(CONFIG_TPL_OF_PLATDATA),dts/dt.dtb) \
+		$(if $(CONFIG_SPL_FIT_SIGNATURE)$(U_BOOT_ITS),u-boot.itb FORCE)
 	$(Q)$(MAKE) obj=spl -f $(srctree)/scripts/Makefile.spl all
 
 spl/sunxi-spl.bin: spl/u-boot-spl
-- 
2.25.1