On 10.1.2017 14:08, Alexander Graf wrote:
On 01/10/2017 02:05 PM, Michal Simek wrote:
On 10.1.2017 14:02, Alexander Graf wrote:
On 01/10/2017 01:58 PM, Michal Simek wrote:
U-Boot configured via DTB can use the same DTB for booting the kernel. When OF_CONTROL is used fdtcontroladdr is setup and can be use for boot.
Signed-off-by: Michal Simek michal.simek@xilinx.com
Didn't check if there is any side effect or not but it looks weird when you have DT driver u-boot that you have to load dtb again.
I agree, and I think it's very reasonable to try and use the same device tree for U-Boot and Linux.
I'm not sure it's a great idea to check for the builtin device tree after ATAGs though. Shouldn't we prefer the built-in one over ATAGs?
No problem to do it. The reason why I have done it in this way was not to change behavior for existing platforms.
u-boot is also doing some automatic updates which can require fdt resize but I didn't check if resize can be done in that space where build-in dtb is.
Good point. It probably makes sense to copy it out, as we do in the EFI boot path (see the copy_fdt() call):
https://github.com/trini/u-boot/blob/master/cmd/bootefi.c#L173
I also agree on the default behavior change problem. But in the patch as is, won't most boards just fall back to ATAG boot?
Only that one which has it enabled. I expect most of boards with has OF_CONTROL enabled are not using ATAG.
Thanks, Michal