From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1W1XDZ-0002pc-30 for barebox@lists.infradead.org; Fri, 10 Jan 2014 08:13:25 +0000 Date: Fri, 10 Jan 2014 09:13:03 +0100 From: Sascha Hauer Message-ID: <20140110081302.GV6750@pengutronix.de> References: <20131212080359.GE24559@pengutronix.de> <20131212195806.GL24559@pengutronix.de> <20131219080917.GW24559@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: Porting barebox (devicetree) to Variscite iMX6 SOM To: Michael Burkey Cc: barebox@lists.infradead.org On Thu, Jan 09, 2014 at 02:20:33AM -0500, Michael Burkey wrote: > A few more comments & questions regarding getting the Variscite SOM up > and working (and it's pretty close to fully working at this point): > > First off, what works: > > 1) Booting from NAND, SD, etc to barebox > 2) Nand programming under barebox > 3) GPIO > 4) I2C > 5) USB > 6) RS232 > etc. > > Basically, things are working pretty well....up to the point of > starting the Linux Kernel. > > Whenever I try to do a "bootm" of pretty much any image type, I run > into issues. I *think* I have everything setup properly on the Linux > command line in the way of bootargs (but I'm still checking a couple > of things). It doesn't matter whether I am launching the kernel from a > partition (NAND), USB, memory, etc. The result is the same regardless. > It *does* decode the kernel header properly, display the version, the > correct load address, etc -- so that's not the issue. > > One thing is that I am using an older kernel that is not setup for > devicetree -- which is hopefully not a major problem. Basically, > everything is specified "the old way" in the kernel platform/board > files (and it works fine from u-boot). And, at least for now, moving > to a newer kernel isn't an option. > > Under barebox, I either get a "launching kernel with devicetree" and > then it hangs, Ok, this is expected since your kernel does not have devicetree support > or, if I do an "oftree -f" and then do a bootm, That's the correct thing to do. With this it should work. > I get > an "unable to dereference NULL pointer" and a restart. You could enable: [*] enable arm exception handling support [*] enable stack unwinding support and [*] kallsyms With this barebox prints a backtrace giving a clue where the NULL pointer deref happens. > > Any quick guesses, suggestions as to what I may be doing wrong? > Is there a proper way to tell barebox (when started with devicetree) > to NOT try to send the devicetree on to the kernel? > > Also, for the moment, I am using Kobs-NG under Linux to actually > program barebox itself into NAND. Once there, it works fine and I can > use barebox itself to program the other NAND partitions. Is adding > support for writing out the FCB/DBBT to the first NAND blocks anywhere > in the current (near-term) to do list for barebox? I noticed that it > looked like you had something similar to this already in barebox for a > couple of the other, earlier iMX cores. > > > Lastly, once I do get this semi-final issue fixed, what is the best > way to submit the code for the Variscite SOM to the main barebox tree > for everyone else to have access to? Just post the patches to the list. I'll include them then. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox