zephyr-kernel: Factor out Yocto toolchain specific variables

Create ZEPHYR_TOOLCHAIN_VARIANT variable with an unchanged default value
of 'yocto'.

To support providing different configuration for different toolchain
variants, require a toolchain-specific inc file.

Create zephyr-toolchain-yocto.inc, and factor out all variables that are
specific to building using the Yocto toolchain.

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Tested-by: Jon Mason <jon.mason@arm.com>
Signed-off-by: Naveen Saini <naveen.kumar.saini@intel.com>

meta-zephyr-core/recipes-kernel/zephyr-kernel/zephyr-kernel-common.inc

@@ -7,8 +7,8 @@ inherit ${ZEPHYR_INHERIT_CLASSES}
 # filesystem.
 IMAGE_NO_MANIFEST = "1"
 
-ZEPHYR_GCC_VARIANT="yocto"
-ZEPHYR_SYSROOT="${STAGING_DIR_TARGET}"
+ZEPHYR_TOOLCHAIN_VARIANT ?= "yocto"
+require zephyr-toolchain-${ZEPHYR_TOOLCHAIN_VARIANT}.inc
 
 ZEPHYR_MAKE_OUTPUT = "zephyr.elf"
 ZEPHYR_MAKE_BIN_OUTPUT = "zephyr.bin"
@@ -16,13 +16,9 @@ ZEPHYR_MAKE_EFI_OUTPUT = "zephyr.efi"
 
 EXTRA_OECMAKE = "\
     -DZEPHYR_BASE=${ZEPHYR_BASE} \
-    -DZEPHYR_GCC_VARIANT=yocto \
     -DBOARD=${BOARD} \
     -DARCH=${ARCH} \
-    -DCROSS_COMPILE=${CROSS_COMPILE} \
-    -DZEPHYR_SYSROOT=${ZEPHYR_SYSROOT} \
-    -DZEPHYR_TOOLCHAIN_VARIANT=yocto \
-    -DEXTRA_CPPFLAGS=${CPPFLAGS} \
+    -DZEPHYR_TOOLCHAIN_VARIANT=${ZEPHYR_TOOLCHAIN_VARIANT} \
     -DZEPHYR_MODULES=${ZEPHYR_MODULES} \
     "
 
@@ -34,8 +30,6 @@ export ZEPHYR_BASE="${S}/zephyr"
 
 DEPENDS += "gperf-native"
 
-CROSS_COMPILE = "${STAGING_BINDIR_TOOLCHAIN}/${TARGET_PREFIX}"
-
 DEPENDS:append:qemuall = " qemu-native qemu-helper-native"
 
 # The makefiles are explicit about the flags they want, so don't unset
@@ -49,12 +43,9 @@ python () {
     d.delVar('LDFLAGS')
 }
 
-OE_TERMINAL_EXPORTS += "CROSS_COMPILE"
 OE_TERMINAL_EXPORTS += "BOARD"
 OE_TERMINAL_EXPORTS += "ZEPHYR_SRC_DIR"
 OE_TERMINAL_EXPORTS += "ZEPHYR_BASE"
-OE_TERMINAL_EXPORTS += "ZEPHYR_SYSROOT"
-OE_TERMINAL_EXPORTS += "ZEPHYR_GCC_VARIANT"
 
 IMAGE_FSTYPES = "elf bin"
 

meta-zephyr-core/recipes-kernel/zephyr-kernel/zephyr-toolchain-yocto.inc

@@ -0,0 +1,16 @@
+# Additional definitions to use the Yocto toolchain
+
+ZEPHYR_GCC_VARIANT="yocto"
+ZEPHYR_SYSROOT="${STAGING_DIR_TARGET}"
+CROSS_COMPILE = "${STAGING_BINDIR_TOOLCHAIN}/${TARGET_PREFIX}"
+
+EXTRA_OECMAKE:append = " \
+    -DZEPHYR_GCC_VARIANT=${ZEPHYR_GCC_VARIANT} \
+    -DCROSS_COMPILE=${CROSS_COMPILE} \
+    -DZEPHYR_SYSROOT=${ZEPHYR_SYSROOT} \
+    -DEXTRA_CPPFLAGS=${CPPFLAGS} \
+    "
+
+OE_TERMINAL_EXPORTS += "CROSS_COMPILE"
+OE_TERMINAL_EXPORTS += "ZEPHYR_SYSROOT"
+OE_TERMINAL_EXPORTS += "ZEPHYR_GCC_VARIANT"