imx-bootlets: move BOARD selection to the machine config

Move the BOARD selection out of the bootlets recipe so it can be used
from machines defined in other layers.

Signed-off-by: Javier Viguera <javier.viguera@digi.com>

meta-digi-arm/conf/machine/ccardimx28js.conf

@@ -4,6 +4,8 @@
 
 include conf/machine/include/ccardimx28.inc
 
+IMXBOOTLETS_MACHINE = "CCARDIMX28JS"
+
 DTSNAME = "imx28-${MACHINE}"
 
 # Use standard serial port name and let device handlers (mdev, udev)

meta-digi-arm/conf/machine/wr21.conf

@@ -6,6 +6,8 @@ include conf/machine/include/mxs-digi-base.inc
 
 SOC_FAMILY = "mxs:mx28"
 
+IMXBOOTLETS_MACHINE = "WR21"
+
 UBOOT_ENTRYPOINT  = "0x41008000"
 UBOOT_LOADADDRESS = "0x41008000"
 

meta-digi-arm/recipes-bsp/imx-bootlets-dey/imx-bootlets-dey_git.bb

@@ -20,9 +20,17 @@ S = "${WORKDIR}/git"
 # Disable parallel building or it may fail to build.
 PARALLEL_MAKE = ""
 
-EXTRA_OEMAKE = "CROSS_COMPILE=${TARGET_PREFIX}"
-EXTRA_OEMAKE_append_ccardimx28js = " BOARD=CCARDIMX28JS"
-EXTRA_OEMAKE_append_wr21 = " BOARD=WR21"
+EXTRA_OEMAKE = "CROSS_COMPILE=${TARGET_PREFIX} BOARD=${IMXBOOTLETS_MACHINE}"
+
+# Ensure machine defines the IMXBOOTLETS_MACHINE
+python () {
+    if not d.getVar("IMXBOOTLETS_MACHINE", True):
+        PN = d.getVar("PN", True)
+        FILE = os.path.basename(d.getVar("FILE", True))
+        bb.debug(1, "To build %s, see %s for instructions on \
+                     setting up your machine config" % (PN, FILE))
+        raise bb.parse.SkipPackage("because IMXBOOTLETS_MACHINE is not set")
+}
 
 do_install () {
 	install -d ${STAGING_DIR_TARGET}/boot