From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bilbo.ozlabs.org (bilbo.ozlabs.org [203.10.76.25]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "bilbo.ozlabs.org", Issuer "CAcert Class 3 Root" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id B4D26DDFB0 for ; Wed, 13 May 2009 12:36:20 +1000 (EST) Date: Wed, 13 May 2009 12:36:14 +1000 From: David Gibson To: Stephen Neuendorffer Subject: Re: device trees. Message-ID: <20090513023614.GJ24338@yookeroo.seuss> References: <20090511155232.A30671B6005D@mail89-va3.bigfish.com> <4A08593C.4010503@dlasys.net> <20090511183638.F07C01438054@mail184-wa4.bigfish.com> <4A08C599.2030100@dlasys.net> <20090512005554.EEE1019D009B@mail129-dub.bigfish.com> <4A08E050.9000302@dlasys.net> <20090512042733.8D4A21400054@mail184-dub.bigfish.com> <20090513001048.490B533005D@mail141-va3.bigfish.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <20090513001048.490B533005D@mail141-va3.bigfish.com> Cc: linuxppc-dev@ozlabs.org, "David H. Lynch Jr." List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, May 12, 2009 at 05:10:46PM -0700, Stephen Neuendorffer wrote: > > Another possibility is to pad the DTB with a DESYNC command and the > correct pad frame, just in case it cannot be prevented. Um.. one thing I'm missing in this discussion of attaching the dtb to the bitstream: I don't see how the bitstream becomes accessible to the kernel at runtime. Unless you were exposing the dtb as part of the fpga programming, but I thought you explicitly weren't doing that because of limited bram space. I imagine this is simply due to my ignorance about FPGA techniques, but if someone could enlighten me...? > > -----Original Message----- > > From: Grant Likely [mailto:grant.likely@secretlab.ca] > > Sent: Monday, May 11, 2009 10:30 PM > > To: Stephen Neuendorffer > > Cc: David H. Lynch Jr.; linuxppc-dev@ozlabs.org > > Subject: Re: device trees. > > > > On Mon, May 11, 2009 at 10:27 PM, Stephen Neuendorffer > > wrote: > > >> > OK, so the key question seems to be *when* the bitstream is > > > associated > > >> > with the > > >> > device tree.  If at bitstream generation time, you can prepend the > > > .dtb > > >> > to the bitstream.  As long as the dtb doesn't contain the magic > > >> > bitstream start code, you can go back and access it later. > > >> > > > >> You really mean prepend ? I was presuming that things would work > > > better > > >> if it was appended ? > > > > > > Yes, actually prepend is simpler because you don't have to know the size > > > of the bitstream. > > > Everything before the SYNC code in the bitstream is ignored. > > > > ...In this case, might need to preprocess the .dtb the escape out the > > possibility of a sync code appearing. > > > > g. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson