[PATCH L-C v2 4/7] linux-custom: add support for kernel config fragments

[Cedric Hombourger <Cedric_Hombourger@mentor.com>]

Check for .cfg files listed in SRC_URI and merge them with the
main defconfig using the kernel merge_config script. The optional
"apply" parameter may be used for the specified fragment to be
ignore (set to "no").

Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com>
---
 .../linux/files/build-kernel.sh               |  3 +++
 meta/recipes-kernel/linux/linux-custom.inc    | 23 +++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/meta/recipes-kernel/linux/files/build-kernel.sh b/meta/recipes-kernel/linux/files/build-kernel.sh
index 386e58b..f56e96c 100644
--- a/meta/recipes-kernel/linux/files/build-kernel.sh
+++ b/meta/recipes-kernel/linux/files/build-kernel.sh
@@ -37,6 +37,9 @@ REPACK_LINUX_IMAGE_DIR="${REPACK_DIR}/linux-image"
 REPACK_LINUX_HEADERS_DIR="${REPACK_DIR}/linux-headers"
 
 make ${KERNEL_CONFIG_TARGET} || exit ${?}
+if [ -n "${KERNEL_FRAGMENTS}" ]; then
+    scripts/kconfig/merge_config.sh -m .config ${KERNEL_FRAGMENTS}
+fi
 
 KV=$( make -s kernelrelease )
 if [ "${KV}" != "${PV}" ]; then
diff --git a/meta/recipes-kernel/linux/linux-custom.inc b/meta/recipes-kernel/linux/linux-custom.inc
index 0c185d8..ca91f64 100644
--- a/meta/recipes-kernel/linux/linux-custom.inc
+++ b/meta/recipes-kernel/linux/linux-custom.inc
@@ -18,6 +18,19 @@ python() {
                          'linux-headers-' + kernel_name)
 }
 
+def config_fragments(d):
+    fragments = []
+    sources = d.getVar("SRC_URI").split()
+    for s in sources:
+        _, _, local, _, _, parm = bb.fetch.decodeurl(s)
+        apply = parm.get("apply")
+        if apply == "no":
+            continue
+        base, ext = os.path.splitext(os.path.basename(local))
+        if ext and ext in (".cfg"):
+            fragments.append(local)
+    return fragments
+
 inherit dpkg-base
 
 SRC_URI += "file://build-kernel.sh"
@@ -71,6 +84,16 @@ dpkg_runbuild() {
 		KERNEL_CONFIG_TARGET="defconfig"
 	fi
 
+	# copy config fragments over to the kernel tree
+	src_frags="${@ " ".join(config_fragments(d)) }"
+	out_frags="${@ " ".join(map(lambda frag: 'debian/fragments/' + frag, config_fragments(d))) }"
+	rm -rf ${S}/debian/fragments
+	if [ -n "${src_frags}" ]; then
+		mkdir -p ${S}/debian/fragments
+		(cd ${WORKDIR} && cp ${src_frags} ${S}/debian/fragments/)
+	fi
+	export KERNEL_FRAGMENTS="${out_frags}"
+
 	E="${@ bb.utils.export_proxies(d)}"
 
 	export PV=${PV}
-- 
2.20.1