Add simple mechanism to specify version-based extra CFLAGS

Platform files can specify extra CFLAGS by extending the kcflags
environment variable. When a kernel tree for a platform contains both
BSP and mainline branches, different CFLAGS may be needed, as BSPs are
usually littered with warnings. Make it possible to specify extra CFLAGS
per kernel version through a new extra_kcflags array.

This mechanism can be extended later if needed by storing version
comparison strings as array keys (e.g. "<=4.19").

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/kbuild.sh b/kbuild.sh
index a0086a8..7980463 100755
--- a/kbuild.sh
+++ b/kbuild.sh
@@ -6,6 +6,7 @@ set -e
 kbuild_root=$(dirname $(readlink -f "$0"))
 
 declare -A cross_compile
+declare -A extra_kcflags
 declare -A target_root
 
 if [[ -r $kbuild_root/config.sh ]] ; then
@@ -16,6 +17,15 @@ fi
 #kbuild_options='C=1'
 kbuild_options="KALLSYMS_EXTRA_PASS=0"
 
+get_kernel_version() {
+	local version=$(cat Makefile | grep '^VERSION = ' | sed 's/.* = //')
+	local patchlevel=$(cat Makefile | grep '^PATCHLEVEL = ' | sed 's/.* = //')
+	local sublevel=$(cat Makefile | grep '^SUBLEVEL = ' | sed 's/.* = //')
+	echo "$version.$patchlevel.$sublevel"
+}
+
+version=$(get_kernel_version)
+
 #
 # Options parsing
 #
@@ -103,6 +113,10 @@ fi
 
 source "${kbuild_root}/platforms/$platform.sh" || exit 1
 
+# Apply version-specific kcflags, useful to suppress warnings based on the
+# kernel version.
+[[ -z "${extra_kcflags[$version]+_}" ]] || kcflags="$kcflags ${extra_kcflags[$version]}"
+
 #
 # Architecture
 #