Date: Mon, 05 Dec 2016 08:01:43 -0700 From: Ian Lepore <ian@freebsd.org> To: Daniel Braniss <danny@cs.huji.ac.il>, arm@freebsd.org Subject: Re: dtb printout Message-ID: <1480950103.1889.251.camel@freebsd.org> In-Reply-To: <7FD12DD6-B390-4EF3-811B-391798410BC0@cs.huji.ac.il> References: <7FD12DD6-B390-4EF3-811B-391798410BC0@cs.huji.ac.il>
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On Mon, 2016-12-05 at 15:48 +0200, Daniel Braniss wrote: > Hi, > the short version: > is there a way to obtain the dtb from the kernel? > > the longer version: > I am developing on several different arm boards, rpi, rpi2, orangepi- > one, orange-pc, to mention > a few, and each one has a different u-boot, ubldr, dtb, and I keep > loosing track :-( > I find myself too often wondering which ddb file got loaded. > > cheers, > danny First: each one does NOT have a different ubldr. All ubldr.bin files are the same, they're not board-specific anymore. (The elf versions, ubldr without the .bin, may have a different load address in the elf header, but other than that, they're identical too and can actually be loaded at any address.) To see the contents of the dtb, use ofwdump. The output is not especially pretty. There is a manpage for it. To just get a quick reminder of which file was loaded, create a /boot/loader.rc.local (<-- .rc not .conf) that contains ubenv import fdtfile fdt_file Then in the running system you can use kenv and you'll see uboot.fdtfile="bcm2835-rpi-b-rev2.dtb" Unfortunately, some u-boots use fdtfile, some use fdt_file. Grrr. You can, of course, use that ubenv import thing to pull any variable from the uboot environment into the kernel environment. If you just say ubenv import without naming a variable, you get all the vars (including vars that contain scripts, which is kind of messy). -- Ian
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