From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754725AbdBPAQv (ORCPT ); Wed, 15 Feb 2017 19:16:51 -0500 Received: from mail-qk0-f182.google.com ([209.85.220.182]:34510 "EHLO mail-qk0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752807AbdBPAQs (ORCPT ); Wed, 15 Feb 2017 19:16:48 -0500 MIME-Version: 1.0 In-Reply-To: References: <1487175261-7051-1-git-send-email-atull@kernel.org> <1487175261-7051-8-git-send-email-atull@kernel.org> <20170215172157.GA3317@obsidianresearch.com> <20170215180612.GB3317@obsidianresearch.com> <20170215203734.GC5531@obsidianresearch.com> <20170215211528.GA9125@obsidianresearch.com> From: Moritz Fischer Date: Wed, 15 Feb 2017 16:16:46 -0800 Message-ID: Subject: Re: [RFC 7/8] fpga-region: add sysfs interface To: Alan Tull Cc: Jason Gunthorpe , matthew.gerlach@linux.intel.com, linux-kernel , linux-fpga@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 15, 2017 at 2:42 PM, Alan Tull wrote: > On Wed, Feb 15, 2017 at 3:36 PM, Moritz Fischer > wrote: >> Jason, >> >> On Wed, Feb 15, 2017 at 1:15 PM, Jason Gunthorpe >> wrote: >>> On Wed, Feb 15, 2017 at 12:54:27PM -0800, Moritz Fischer wrote: >>> >>>> Well I don't know ;-) With something fdt based we already have >>>> parsers there, >>> >>> Not sure.. How does incbin work in DTB? >>> >>> We have the FPGA in a s/g list so we cannot pass the entire file to >>> libfdt - is that consistent with incbin? >> >> Well you could attach the (for lack of better word) blob to the beginning, >> instead of doing incbin >> >>> Can we force a specific alignment for the included data? >> >> I'd say probably, but haven't checked. >> >>> How complex will the userspace tool be to make the image? >> >> Userspace can be as complex as it needs to be, imho, if it makes >> kernel space easier & safer. >> >> I'll need to do some more reading over the weekend before I can make >> more sensible comments :) >> >> Thanks, >> >> Moritz > > Another thought I have about this is that adding the header to > bitstreams can be a piece of independence from DT for systems that > aren't already using DT. This includes x86 in Linux. It also > includes other OS's that aren't using DT, they can reuse the same > image files without having to add dtc. As much as I like DT, it is > something I'm having to think about. Just to clarify: I was proposing using the binary format of dts, not actually requiring devicetree for it to work. There's plenty of people running u-boot on x86 using FIT images to boot. W.r.t to Jason's script, it's there. Almost any company dealing with Xilinx FPGAs will have one of those. We have one, too. I recall having seen another one made and shared by Mike @ topic. While it's a good starting point ,I *really* don't like the idea parsing user-land provided strings in kernel space in a parser that we open-code. Good discussion ;-) Cheers, Moritz