On 8/31/19 1:52 PM, Anton Leontiev wrote:
чт, 29 авг. 2019 г. в 23:35, Stephen Warren swarren@wwwdotorg.org:
On 8/29/19 5:20 AM, Anton Leontiev wrote:
2019-08-26 at 18:59, Stephen Warren swarren@wwwdotorg.org: We have a GNU/Linux distribution that use FDTDIR in its extlinux.conf to support several boards. But some boards have FDT embedded in U-Boot and it is't present in FDTDIR. In such configuration U-Boot fails to boot an entry, despite no exact FDT is specified in it. Distribution itself is designed to work on any board.
I lookead at that referenced commit description in full and the code, and I believe what you want is for U-Boot to set fdt_addr to the location of the in-RAM DT, and leave fdt_addr_r unset. This will indicate to the pxe code that no FDT should be loaded when parsing extlinux.conf, but instead to use fdt_addr directly.
Does that work for you, or does it break some other script/use-case on this board?
Indeed, it's a possible option. However, if fdt_addr_r is not set, user can't override embedded FDT using extlinux.conf. README.distro says about fdt_addr_r: "This is mandatory even when fdt_addr is provided, since extlinux.conf must always be able to provide a DTB which overrides any copy provided by the HW."
So it should be considered as a workaround rather than a solution.
OK, I guess that makes sense.
I suppose it's not reasonable to ask that extlinux.conf doesn't contain an FDTDIR statement in the case where the specific board has a built-in DT, since the extlinux.conf content is supposed to be generic, and not tailored to the current HW.