[LEDE-DEV] Adding support for dlink dwr-512

[Giuseppe Lippolis]

Dear Mathias,
thanks for your info.

Just a couple of question before to proceed.

1) From my understanding the append-dtb seems to append the dtb after the
kernel. But in this way in my opinion the kernel cannot point to the dbt
(remember that currently It seems that the oem bootloader cannot pass kernel
parameter). 
In the
build_dir/target-mipsel_24kc_musl-1.1.15/linux-ramips_rt305x/linux-4.4.23/ar
ch/mips/ralink/of.c the __dt_setup_arch(&__image_dtb); point to the
__image_dtb area embedded in the kernel. This area should be populated after
the compilation process by the patch-dtb tool. Shall I use the "KERNEL :=
kernel-bin | patch-dtb | lzma" config  instead?

2) Currently I make this patch

diff --git a/target/linux/ramips/image/rt305x.mk
b/target/linux/ramips/image/rt305x.mk
index be21ac4..f768785 100644
--- a/target/linux/ramips/image/rt305x.mk
+++ b/target/linux/ramips/image/rt305x.mk
@@ -168,6 +168,17 @@ endef
 TARGET_DEVICES += dir-620-d1


+define Device/dwr-512-b
+  DTS := DWR-512-B
+  KERNEL := kernel-bin | patch-dtb | lzma
+  IMAGES := factory.bin
+  IMAGE/factory.bin := \
+       append-kernel
+  DEVICE_TITLE := D-Link DWR-512 B
+endef
+TARGET_DEVICES += dwr-512-b

But If run the make script I get the same files I had before in the
bin/targets/ramips/rt305x/
lede-ramips-rt305x-dwr-512-b-initramfs-kernel.bin  
lede-ramips-rt305x-dwr-512-b-squashfs-factory.bin
lede-ramips-rt305x-dwr-512-b-squashfs-sysupgrade.bin  
lede-ramips-rt305x-root.squashfs                   
lede-ramips-rt305x-uImage-initramfs.bin
lede-ramips-rt305x-uImage.bin                         
lede-ramips-rt305x-vmlinux-initramfs.bin           
lede-ramips-rt305x-vmlinux-initramfs.elf
lede-ramips-rt305x-vmlinux.bin                        
lede-ramips-rt305x-vmlinux.elf


what shall I do to propagate the change effect in the
target/linux/ramips/image/rt305x.mk b/target/linux/ramips/image/rt305x.mk?
Currently the only way I found to apply a change in the target/linux/... is:
Make distclean
Make menuconfig
Make

But this is annoying (every time recompile all). Do you have some advice
about?

Thanks.