[OE-core] [PATCH] module.bbclass: Add devshell support

[Stefan Wiehler]

Adds development shell support for out-of-tree kernel modules by reproducing
the build environment of the compile task.

Signed-off-by: Stefan Wiehler <stefan.wiehler at missinglinkelectronics.com>
---
 meta/classes/module.bbclass | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/meta/classes/module.bbclass b/meta/classes/module.bbclass
index 802476bc7a..9b019513ae 100644
--- a/meta/classes/module.bbclass
+++ b/meta/classes/module.bbclass
@@ -1,6 +1,7 @@
 inherit module-base kernel-module-split pkgconfig
 
 addtask make_scripts after do_prepare_recipe_sysroot before do_compile
+addtask make_scripts after do_prepare_recipe_sysroot before do_devshell
 do_make_scripts[lockfiles] = "${TMPDIR}/kernel-scripts.lock"
 do_make_scripts[depends] += "virtual/kernel:do_shared_workdir"
 
@@ -18,6 +19,26 @@ python __anonymous () {
     d.setVar('KBUILD_EXTRA_SYMBOLS', " ".join(extra_symbols))
 }
 
+python do_devshell_prepend () {
+    os.environ['CFLAGS'] = ''
+    os.environ['CPPFLAGS'] = ''
+    os.environ['CXXFLAGS'] = ''
+    os.environ['LDFLAGS'] = ''
+
+    os.environ['KERNEL_PATH'] = d.getVar('STAGING_KERNEL_DIR')
+    os.environ['KERNEL_SRC'] = d.getVar('STAGING_KERNEL_DIR')
+    os.environ['KERNEL_VERSION'] = d.getVar('KERNEL_VERSION')
+    os.environ['CC'] = d.getVar('KERNEL_CC')
+    os.environ['LD'] = d.getVar('KERNEL_LD')
+    os.environ['AR'] = d.getVar('KERNEL_AR')
+    os.environ['O'] = d.getVar('STAGING_KERNEL_BUILDDIR')
+    kbuild_extra_symbols = d.getVar('KBUILD_EXTRA_SYMBOLS')
+    if kbuild_extra_symbols:
+        os.environ['KBUILD_EXTRA_SYMBOLS'] = kbuild_extra_symbols
+    else:
+        os.environ['KBUILD_EXTRA_SYMBOLS'] = ''
+}
+
 module_do_compile() {
 	unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS
 	oe_runmake KERNEL_PATH=${STAGING_KERNEL_DIR}   \
-- 
2.11.0