From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerry Van Baren Date: Wed, 29 Nov 2006 09:01:49 -0500 Subject: [U-Boot-Users] RFC: flattened device tree command Message-ID: <456D92CD.9070203@smiths-aerospace.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Wolfgang, Grant, and gentle readers, A while back I submitted a patch for a new command "oftdump". While it was good in principle, it probably is premature and short sighted in implementation. The command was hacked on top of ft_dump_blob() (common/ft_build.c) and required some changes to the same. Grant objected to the changes as suboptimal - I contend they are locally optimal, but that ft_build.c is suboptimal. The linux kernel has its own library functions for handling flat device trees. In addition, David Gibson has proposed another library (advertised as easier to use): My RFC has two parts: 1) Peoples' opinion of the relative merits of the current u-boot support library vs. the kernel's library vs. David Gibson's library. My limited experience with ft_build.c is that it is suboptimal. I don't have any experience with the linux or David's libraries to form an opinion of them. 2) I see more commands than just dumping the tree, allowing the user to manipulate the tree as well. My current thoughts are to make a new command "fdt" (flattened device tree - the Open Firmware genesis appears to be depricated) with subcommands like the existing "mii" command. fdt read - does what my "oftdump" command does fdt write - allow patching the fdt * Writing could get pretty complex with creating nodes * Initial implementation would be simply to change existing values Related to the above discussion, the current ft_build.c/"bootm" code takes the blob and augments it with board configuration and env stuff as part of the "bootm" command. The implementation is suboptimal (ft_build.c again) in that it is only done as a last thing before "bootm" transfers to linux, making it (almost) impossible to dump and definitely impossible to interactively poke around in the resulting fdt. I would like to see this integrated done better in u-boot rather than simply pasted onto the fdt at the last moment before jumping into linux. So, in conclusion, 1) I'm not sure if this is truly a RFC or just a brain dump of my current thoughts. Either way, advice is welcome. 2) Wolfgang: Please don't apply my "oftdump" command patch yet. gvb