From 82f766d1d2c580a29bed340ea4dd9fa1b8ff05e0 Mon Sep 17 00:00:00 2001 From: Alex Deymo Date: Sun, 2 Apr 2017 01:25:20 -0700 Subject: Allow boards to initialize the DT at runtime. In some boards like the Raspberry Pi the initial bootloader will pass a DT to the kernel. When using U-Boot as such kernel, the board code in U-Boot should be able to provide U-Boot with this, already assembled device tree blob. This patch introduces a new config option CONFIG_OF_BOARD to use instead of CONFIG_OF_EMBED or CONFIG_OF_SEPARATE which will initialize the DT from a board-specific funtion instead of bundling one with U-Boot or as a separated file. This allows boards like the Raspberry Pi to reuse the device tree passed from the bootcode.bin and start.elf firmware files, including the run-time selected device tree overlays. Signed-off-by: Alex Deymo Reviewed-by: Simon Glass --- doc/README.fdt-control | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'doc/README.fdt-control') diff --git a/doc/README.fdt-control b/doc/README.fdt-control index c965629905..378b06b108 100644 --- a/doc/README.fdt-control +++ b/doc/README.fdt-control @@ -130,6 +130,10 @@ u-boot-dtb.bin which does the above step for you also. If you are using CONFIG_SPL_FRAMEWORK, then u-boot.img will be built to include the device tree binary. +If CONFIG_OF_BOARD is defined, a board-specific routine will provide the +device tree at runtime, for example if an earlier bootloader stage creates +it and passes it to U-Boot. + If CONFIG_OF_HOSTFILE is defined, then it will be read from a file on startup. This is only useful for sandbox. Use the -d flag to U-Boot to specify the file to read. -- cgit v1.2.3