devicetree: Add support for DT overlays with RPi bootloader

Compile overlay device trees and put them in 'overlays/' folder
on sdcard RPi boot partition.

Change-Id: I3da0032b3c2618165008eec1fc94e97824d09099
Signed-off-by: Francois Muller <francois@concept-embarque.fr>

2 files changed, 31 insertions, 6 deletions

diff --git a/classes/sdcard_image-rpi.bbclass b/classes/sdcard_image-rpi.bbclass
index 63cd62a..43f1346 100644
--- a/classes/sdcard_image-rpi.bbclass
+++ b/classes/sdcard_image-rpi.bbclass
@@ -66,6 +66,11 @@ SDIMG = "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.rpi-sdimg"
 # Additional files and/or directories to be copied into the vfat partition from the IMAGE_ROOTFS.
 FATPAYLOAD ?= ""
 
+# Device Tree Overlays are assumed to be suffixed by '-overlay.dtb' string and will be put in a dedicated folder
+DT_ALL = "${@d.getVar('KERNEL_DEVICETREE', True) or ''}"
+DT_OVERLAYS = "${@oe.utils.str_filter('\S+\-overlay\.dtb$', '${DT_ALL}', d)}"
+DT_ROOT = "${@oe.utils.str_filter_out('\S+\-overlay\.dtb$', '${DT_ALL}', d)}"
+
 IMAGEDATESTAMP = "${@time.strftime('%Y.%m.%d',time.gmtime())}"
 
 IMAGE_CMD_rpi-sdimg () {
@@ -104,15 +109,20 @@ IMAGE_CMD_rpi-sdimg () {
                 ;;
         *)
                 if test -n "${KERNEL_DEVICETREE}"; then
-                        for DTB in ${KERNEL_DEVICETREE}; do
-                                if echo ${DTB} | grep -q '/dts/'; then
-                                        bbwarn "${DTB} contains the full path to the the dts file, but only the dtb name should be used."
-                                        DTB=`basename ${DTB} | sed 's,\.dts$,.dtb,g'`
-                                fi
+                        # Copy board device trees to root folder
+                        for DTB in ${DT_ROOT}; do
                                 DTB_BASE_NAME=`basename ${DTB} .dtb`
 
                                 mcopy -i ${WORKDIR}/boot.img -s ${DEPLOY_DIR_IMAGE}/${KERNEL_IMAGETYPE}-${DTB_BASE_NAME}.dtb ::${DTB_BASE_NAME}.dtb
                         done
+
+                        # Copy device tree overlays to dedicated folder
+                        mmd -i ${WORKDIR}/boot.img overlays
+                        for DTB in ${DT_OVERLAYS}; do
+                                DTB_BASE_NAME=`basename ${DTB} .dtb`
+
+                                mcopy -i ${WORKDIR}/boot.img -s ${DEPLOY_DIR_IMAGE}/${KERNEL_IMAGETYPE}-${DTB_BASE_NAME}.dtb ::overlays/${DTB_BASE_NAME}.dtb
+                        done
                 fi
                 mcopy -i ${WORKDIR}/boot.img -s ${DEPLOY_DIR_IMAGE}/${KERNEL_IMAGETYPE}${KERNEL_INITRAMFS}-${MACHINE}.bin ::kernel.img
                 ;;
diff --git a/conf/machine/raspberrypi.conf b/conf/machine/raspberrypi.conf
index 01021ca..af0907e 100644
--- a/conf/machine/raspberrypi.conf
+++ b/conf/machine/raspberrypi.conf
@@ -25,7 +25,22 @@ XSERVER = " \
 KERNEL_IMAGETYPE ?= "Image"
 
 # Really supported starting from linux-rapsberry 3.18.y only !
-#KERNEL_DEVICETREE ?= "bcm2708-rpi-b.dtb bcm2708-rpi-b-plus.dtb"
+#KERNEL_DEVICETREE ?= " \
+#       bcm2708-rpi-b.dtb \
+#       bcm2708-rpi-b-plus.dtb \
+#       ds1307-rtc-overlay.dtb \
+#       hifiberry-amp-overlay.dtb \
+#       hifiberry-dac-overlay.dtb \
+#       hifiberry-dacplus-overlay.dtb \
+#       hifiberry-digi-overlay.dtb \
+#       iqaudio-dac-overlay.dtb \
+#       iqaudio-dacplus-overlay.dtb \
+#       lirc-rpi-overlay.dtb \
+#       pcf8523-rtc-overlay.dtb \
+#       pps-gpio-overlay.dtb \
+#       w1-gpio-overlay.dtb \
+#       w1-gpio-pullup-overlay.dtb \
+#       "
 
 MACHINE_FEATURES = "kernel26 apm usbhost keyboard vfat ext2 screen touchscreen alsa bluetooth wifi sdio"