[PATCH] ARM: k3: allow to take signing key from environment variable

[Sascha Hauer <s.hauer@pengutronix.de>]

This adds a new Kconfig option CONFIG_ARCH_K3_SIGNING_KEY_ENV. With
this option enabled the content of CONFIG_ARCH_K3_SIGNING_KEY is treated
as the name of an environment variable from which the private key
file/uri is taken. This allows for better integration with build
systems.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 arch/arm/mach-k3/Kconfig |  8 ++++++++
 images/Makefile.k3       | 12 +++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-k3/Kconfig b/arch/arm/mach-k3/Kconfig
index ecd77d8d9a..58f6ba827d 100644
--- a/arch/arm/mach-k3/Kconfig
+++ b/arch/arm/mach-k3/Kconfig
@@ -81,6 +81,14 @@ config ARCH_K3_SIGNING_KEY_CUSTOM
 
 endchoice
 
+config ARCH_K3_SIGNING_KEY_ENV
+	bool "Specify signing key in environment"
+	depends on ARCH_K3_SIGNING_KEY_CUSTOM
+	help
+	  If this option is enabled the content of CONFIG_ARCH_K3_SIGNING_KEY
+	  is treated as name of an environment variable rather than a filename/uri
+	  directly which allows for better integration with build systems.
+
 config ARCH_K3_SIGNING_KEY
 	string "Signing key"
 	depends on ARCH_K3_SIGNING_KEY_CUSTOM
diff --git a/images/Makefile.k3 b/images/Makefile.k3
index 1a8bfe641a..9de48f4d2b 100644
--- a/images/Makefile.k3
+++ b/images/Makefile.k3
@@ -17,10 +17,20 @@ image-$(CONFIG_MACH_BEAGLEPLAY) += barebox-beagleplay.img
 
 endif
 
+
+
 ifdef CONFIG_ARCH_K3_SIGNING_KEY_TI_DEVEL
 KEY_custmpk=$(srctree)/arch/arm/mach-k3/custMpk.pem
 else
-KEY_custmpk="$(CONFIG_ARCH_K3_SIGNING_KEY)"
+
+k3_sigining_key=$(call remove_quotes,$(CONFIG_ARCH_K3_SIGNING_KEY))
+
+ifeq ($(CONFIG_ARCH_K3_SIGNING_KEY_ENV),y)
+KEY_custmpk=$(shell echo $$$(k3_sigining_key))
+else
+KEY_custmpk=$(k3_sigining_key)
+endif
+
 endif
 KEY_degenerate=$(srctree)/arch/arm/mach-k3/ti-degenerate-key.pem
 
-- 
2.47.3