linux: gigevision kernel driver build setup

It is just an empty driver for now :)

drivers/linux-gv/Kbuild

@@ -0,0 +1,3 @@
+ccflags-y := $(MODULE_CFLAGS)
+obj-m := aravis_gv.o
+aravis_gv-y := $(patsubst $(src)/%.c,%.o,$(wildcard $(src)/*.c))

drivers/linux-gv/arvgvkmod.c

@@ -0,0 +1,18 @@
+#include <linux/module.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Emmanuel Pacaud <emmanuel@gnome.org>");
+
+int
+init_module(void)
+{
+	printk (KERN_ALERT "aravis: loaded\n");
+
+	return 0;
+}
+
+void
+cleanup_module(void)
+{
+	printk (KERN_ALERT "aravis: unloaded\n");
+}

drivers/linux-gv/meson.build

@@ -0,0 +1,13 @@
+gv_mkfile = custom_target('gv_makefile', output:'Makefile', command:['touch', '@OUTPUT@'])
+
+gv_sources = files([
+  'arvgvkmod.c'
+])
+
+custom_target ('gv_kmod',input: gv_sources, output: 'aravis_gv.ko', command:[
+  'make', '-j4', '-C', kernel_build_dir,
+  'M='+join_paths(meson.current_build_dir()),
+  'src='+join_paths(meson.current_source_dir()),
+  'MODULE_CFLAGS=-I'+meson.current_source_dir(),
+  'modules'], depends:gv_mkfile, build_by_default:true)
+

drivers/meson.build

@@ -0,0 +1,12 @@
+if host_machine.system()=='linux'
+  kernel_version = run_command('uname', '-r').stdout().strip()
+  kernel_build_dir = join_paths('/', 'lib', 'modules', kernel_version, 'build')
+
+  # test running make in kernel directory, using "make kernelversion"
+  make_returncode = run_command('make', '-sC', kernel_build_dir, 'kernelversion').returncode()
+  if make_returncode != 0
+    error('Cannot compile kernel modules as requested - are kernel headers installed?')
+  endif
+
+  subdir('linux-gv')
+endif

drivers/mesonbuildkmod.sh

@@ -0,0 +1,7 @@
+mkdir -p "$2/drivers/kmod.dir"
+cp -Rf   "$1/drivers/"* "$2/drivers/kmod.dir"
+rm -f    "$2/drivers/kmod.dir/meson.build" "$2/drivers/kmod.dir/mesonbuild.sh"
+cd       "$2/drivers/kmod.dir"
+sed -i -e "s|\$(src)|$1/drivers|" "$2/drivers/kmod.dir/Kbuild"
+make
+mv       "aravis_gv.ko" "$2/drivers"

meson.build

@@ -91,6 +91,10 @@ viewer_deps = aravis_dependencies + [dependency ('gtk+-3.0', version: '>=3.12',
 subdir ('po', if_found: viewer_deps)
 subdir ('viewer', if_found: viewer_deps)
 
+if get_option('drivers')
+  subdir('drivers')
+endif
+
 gst_option = get_option ('gst-plugin')
 gst_deps = aravis_dependencies + [dependency ('gstreamer-base-1.0', required: gst_option),
                                   dependency ('gstreamer-app-1.0', required: gst_option)]

meson_options.txt

@@ -8,6 +8,8 @@ option('packet-socket', type: 'feature', value: 'auto', description : 'Enable pa
 option('tests', type: 'boolean', value: true, description: 'Build tests')
 option('fast-heartbeat', type: 'boolean', value: false, description: 'Enable faster heartbeat rate')
 
+option('drivers', type: 'boolean', value: false, description: 'Build linux driver')
+
 # Documentation and introspection
 
 option('documentation', type: 'feature', value: 'auto', description: 'Build API reference (requires gtk-doc and xlstproc)')