From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerhard Pircher Date: Fri, 22 Jun 2007 14:40:15 +0200 Subject: [U-Boot-Users] How to add device tree support to a board? In-Reply-To: <467B243E.2020508@gmail.com> References: <20070621164721.92910@gmx.net> <467B243E.2020508@gmail.com> Message-ID: <20070622124015.313400@gmx.net> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi, -------- Original-Nachricht -------- Datum: Thu, 21 Jun 2007 21:22:06 -0400 Von: Jerry Van Baren An: Gerhard Pircher CC: u-boot-users at lists.sourceforge.net Betreff: Re: [U-Boot-Users] How to add device tree support to a board? > It is hard to say. I've done the Freescale MPC8360EMDS eval board, > which is a whole different animal than an AmigaOneG3SE (and I don't know > exactly what an AmigaOneG3SE is). Sorry! My fault. Well, the AmigaOne is a ATX motherboard with a G3/G4 PPC CPU, a common VIA 82C686B southbridge (with an i8259 interrupt controller, IDE, USB, etc.), an onboard ethernet controller and a number of PCI/AGP slots. > If you don't have any fixups/additions necessary for the fdt, then it > theoretically is "enable and it just works" but you will be blazing new > ground and I wouldn't bet on it being quite that simple. It never seems > to be. :-/ That depends on what U-boot automatically adds to the device tree. I don't think that U-boot adds nodes for every ISA device found in the PCI2ISA bridge, right? If so, I have to do some fixups anyway, either in U-boot or in the Linux kernel. > If you look at my page FDT page, you will see a table of known > conversions, most of which have not happened yet (only the MPC8360 > family has been worked on). > Thanks! I was searching through the U-boot documentation on www.denx.de, but didn't find anything about Fdt yet. > There are three areas that fix up fdt entries: board setup, CPU setup, > and PCI setup. These do fixups on things like ethernet MAC addresses > (set them from the env variables) and clock frequencies. I would guess > that your AmigaOneG3SE won't need these fixed up, with the possible > exception of the MAC addresses. The current boards that have fixups > have different boards and/or configurations that can run with different > PCI and CPU clock frequencies, for instance, so the fdt property has to > be fixed up with the correct frequency for the given configuration. Looks like the AmigaOne U-boot code has to do a lot fixups (for different CPU frequencies, resource fixups for invisible PCI I/O bars, ISA devices, etc.). > FWIIW, I'm coming out of my busy cycle of the month (first 2+ weeks) and > am getting ready to update the u-boot-fdt fork with respins of some of > the existing patches and some improvements (primarily addressing Kim's > concerns). I hope to get this published and pushed to the u-boot-fdt > repo this week, probably spilling into next week. BTW: As far as I understand there are two implementations for flattened device trees in U-boot. Is libfdt compatible with operating systems that expect only the old bd_t stucture? AFAIK the other implementation is deprecated, but can be switched off by setting an environment variable. > Good luck, Thanks! Gerhard -- Psssst! Schon vom neuen GMX MultiMessenger geh?rt? Der kanns mit allen: http://www.gmx.net/de/go/multimessenger