[PATCH] u-boot: ensure keys are generated before assembling U-Boot FIT image

[rogerio.borin@gmail.com]

From: Rogerio Guerra Borin <rogerio.borin@toradex.com>

Add the task dependency:

do_uboot_assemble_fitimage -> virtual/kernel:do_kernel_generate_rsa_keys

to ensure the kernel FIT image signing keys are available when creating
the U-Boot DTB. This is done only if the signing of the kernel FIT image
is enabled (UBOOT_SIGN_ENABLE="1").

The lack of the dependency causes build errors when executing a build
with no kernel FIT keys initially present in the keys directory. In such
cases one would see an output like this in the Bitbake logs:

Log data follows:
| DEBUG: Executing shell function do_uboot_assemble_fitimage
| Couldn't open RSA private key: '/workdir/build/keys/fit/dev.key': No such file or directory
| Failed to sign 'signature' signature node in 'conf-1' conf node
| FIT description: Kernel Image image with one or more FDT blobs
| ...

This issue was introduced by commit 259bfa86f384 where the dependency
between U-Boot and the kernel was removed (for good reasons). Before
that commit the dependency was set via DEPENDS so that, in terms of
tasks, one had:

u-boot:do_configure -> virtual/kernel:do_populate_sysroot

and the chain leading to the key generation was:

virtual/kernel:do_populate_sysroot -> virtual/kernel:do_install
virtual/kernel:do_install -> virtual/kernel:do_assemble_fitimage
virtual/kernel:do_assemble_fitimage -> virtual/kernel:do_kernel_generate_rsa_keys

With the removal of the first dependency, no more guarantees exist that
the keys would be present when assembling the U-Boot FIT image. That's
the situation we are solving with the present commit.

Fixes: 259bfa86f384 ("u-boot: kernel-fitimage: Fix dependency loop if UBOOT_SIGN_ENABLE and UBOOT_ENV enabled")
Signed-off-by: Rogerio Guerra Borin <rogerio.borin@toradex.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Sean Anderson <sean.anderson@seco.com>
Cc: Adrian Freihofer <adrian.freihofer@siemens.com>
---
 meta/classes-recipe/uboot-sign.bbclass | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/meta/classes-recipe/uboot-sign.bbclass b/meta/classes-recipe/uboot-sign.bbclass
index 76a81546e34..7744e0c5ab5 100644
--- a/meta/classes-recipe/uboot-sign.bbclass
+++ b/meta/classes-recipe/uboot-sign.bbclass
@@ -113,6 +113,8 @@ python() {
     sign = d.getVar('UBOOT_SIGN_ENABLE') == '1'
     if d.getVar('UBOOT_FITIMAGE_ENABLE') == '1' or sign:
         d.appendVar('DEPENDS', " u-boot-tools-native dtc-native")
+    if sign:
+        d.appendVarFlag('do_uboot_assemble_fitimage', 'depends', ' virtual/kernel:do_kernel_generate_rsa_keys')
 }
 
 concat_dtb() {
-- 
2.34.1