fs: change the way the device table is configured

Until now, the location of the device table was specified by a
variable in board Makefiles. Unfortunately, this variable is not
accessible from fs/common.mk, since the target/ code is included
*after* fs/common.mk.

Anyway, the general idea is to move away from these boards Makefile,
and provide configuration option for things like the device table
location.

Therefore, this patch adds a BR2_ROOTFS_DEVICE_TABLE option which
allows to specify which device table should be used.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

fs/Config.in

@@ -15,6 +15,14 @@ config BR2_ROOTFS_POST_BUILD_SCRIPT
 	  only argument. Make sure the exit code of that script is 0,
 	  otherwise make will stop after calling it.
 
+config BR2_ROOTFS_DEVICE_TABLE
+       string "Path to the device table"
+       default "target/generic/device_table.txt"
+       help
+         Specify the location of a device table, that will be passed
+         to the makedevs utility to create all the special device
+         files in the target filesystem.
+
 source "fs/cramfs/Config.in"
 source "fs/cloop/Config.in"
 source "fs/ext2/Config.in"

fs/common.mk

@@ -28,6 +28,7 @@
 # macro will automatically generate a compressed filesystem image.
 
 FAKEROOT_SCRIPT = $(BUILD_DIR)/_fakeroot.fs
+ROOTFS_DEVICE_TABLE = $(call qstrip,$(BR2_ROOTFS_DEVICE_TABLE))
 
 define ROOTFS_TARGET_INTERNAL
 
@@ -38,8 +39,8 @@ $(BINARIES_DIR)/rootfs.$(1): $(ROOTFS_$(2)_DEPENDENCIES) host-fakeroot makedevs
 	touch $(BUILD_DIR)/.fakeroot.00000
 	cat $(BUILD_DIR)/.fakeroot* > $(FAKEROOT_SCRIPT)
 	echo "chown -R 0:0 $(TARGET_DIR)" >> $(FAKEROOT_SCRIPT)
-ifneq ($(TARGET_DEVICE_TABLE),)
-	echo "$(HOST_DIR)/usr/bin/makedevs -d $(TARGET_DEVICE_TABLE) $(TARGET_DIR)" >> $(FAKEROOT_SCRIPT)
+ifneq ($(ROOTFS_DEVICE_TABLE),)
+	echo "$(HOST_DIR)/usr/bin/makedevs -d $(ROOTFS_DEVICE_TABLE) $(TARGET_DIR)" >> $(FAKEROOT_SCRIPT)
 endif
 	echo "$(ROOTFS_$(2)_CMD)" >> $(FAKEROOT_SCRIPT)
 	chmod a+x $(FAKEROOT_SCRIPT)