[PATCH v3 13/14] linux-module: Simplify interface to module makefiles

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Jan Kiszka <jan.kiszka@siemens.com>

Not all module makefile respect DESTDIR nor even have build targets
which take KDIR as input. So call the kernel makefile ourselves, just
requiring the module makefile to provide Kbuild rules.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 RECIPE-API-CHANGELOG.md                             | 5 +++++
 meta/recipes-kernel/linux-module/files/debian/rules | 6 ++++++
 meta/recipes-kernel/linux-module/module.inc         | 1 +
 3 files changed, 12 insertions(+)

diff --git a/RECIPE-API-CHANGELOG.md b/RECIPE-API-CHANGELOG.md
index 2bc1585..dcfbbee 100644
--- a/RECIPE-API-CHANGELOG.md
+++ b/RECIPE-API-CHANGELOG.md
@@ -131,3 +131,8 @@ In order to use the same file permissions for an input file to a dpkg-raw
 package on the build machine as well as on the target, its absolute target path
 needs to be listed in the PRESERVE_PERMS variable (space-separated list of
 files). Otherwise, default permissions are used.
+
+### Reduce requirements on custom module makefiles
+
+It's now sufficient to provide only kbuild rules. Makefile targets like modules
+or modules_install as well as KDIR and DESTDIR evaluation are no longer needed.
diff --git a/meta/recipes-kernel/linux-module/files/debian/rules b/meta/recipes-kernel/linux-module/files/debian/rules
index 5c1d8be..7a89e41 100755
--- a/meta/recipes-kernel/linux-module/files/debian/rules
+++ b/meta/recipes-kernel/linux-module/files/debian/rules
@@ -21,5 +21,11 @@ ifneq (,$(findstring 86,$(DEB_HOST_GNU_CPU)))
 export ARCH=x86
 endif
 
+override_dh_auto_build:
+	$(MAKE) -C $(KDIR) M=$(PWD) modules
+
+override_dh_auto_install:
+	$(MAKE) -C $(KDIR) M=$(PWD) INSTALL_MOD_PATH=$(PWD)/debian/$(PN) modules_install
+
 %:
 	CFLAGS= LDFLAGS= dh $@ --parallel
diff --git a/meta/recipes-kernel/linux-module/module.inc b/meta/recipes-kernel/linux-module/module.inc
index 5d85200..cb7b8ad 100644
--- a/meta/recipes-kernel/linux-module/module.inc
+++ b/meta/recipes-kernel/linux-module/module.inc
@@ -43,4 +43,5 @@ dpkg_runbuild_prepend() {
         export KDIR=$(dpkg -L --root=${BUILDCHROOT_DIR} ${KERNEL_DEP} | \
                       grep "/lib/modules/.*/build")
     fi
+    export PN=${PN}
 }
-- 
2.16.4