From owner-freebsd-arm@FreeBSD.ORG Tue Oct 7 16:40:40 2014 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 4F1BAF2E; Tue, 7 Oct 2014 16:40:40 +0000 (UTC) Received: from mail-yh0-x232.google.com (mail-yh0-x232.google.com [IPv6:2607:f8b0:4002:c01::232]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id EE1AAB9E; Tue, 7 Oct 2014 16:40:39 +0000 (UTC) Received: by mail-yh0-f50.google.com with SMTP id a41so3157516yho.9 for ; Tue, 07 Oct 2014 09:40:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=q1ZriWbefiRSuDcNKnoWUUaxNeOuaYwExu6ayxmyUjk=; b=Xig+IkonyI0L2fxWAz3mAP4Sjj32DEpgq2794d02KiwkmAdFr/jMUGE99FFETdsX+m wJ02mAobvtZXuhb/ofJHa3aqb7ih+9xOsIzYOdbCKeYMRuZ1qCLZRtsQR3KTDedrkblo yHLQ+5c6tXD0vdWFG2pf9saH7UU8DAznIYP8rJ0DCpjwo3z9iu0hgFnTaZku60UJTXJg UYRhVSb9DFYU53dsXsuCKyuNcABA/IXJLbuuYLZVbt/O9GRcFB4Mdu03MvIiuPEGOXDF kjQviTvZUmaFSSK3Jbth806Pz5y29ciCFj3EPmP0wVU6XYoSUETHHm5lzPjAf0wH43jn p6/w== MIME-Version: 1.0 X-Received: by 10.236.78.200 with SMTP id g48mr6779988yhe.17.1412700039094; Tue, 07 Oct 2014 09:40:39 -0700 (PDT) Received: by 10.170.186.141 with HTTP; Tue, 7 Oct 2014 09:40:38 -0700 (PDT) In-Reply-To: <1412687805.12052.199.camel@revolution.hippie.lan> References: <27A69721-D93D-4D4C-883A-718CFFF52B21@bsdimp.com> <1412613830.12052.121.camel@revolution.hippie.lan> <1412687805.12052.199.camel@revolution.hippie.lan> Date: Tue, 7 Oct 2014 09:40:38 -0700 Message-ID: Subject: Re: Digi CCWMX53 From: Russell Haley To: Ian Lepore Content-Type: text/plain; charset=UTF-8 Cc: freebsd-arm X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Oct 2014 16:40:40 -0000 Ian, Thanks for your candid response. I was waiting for this shoe to drop. I would not say I am discouraged, I would say that my expectations have been tempered. Let me evaluate what you have said and I will consider my options. Thanks, Russ On Tue, Oct 7, 2014 at 6:16 AM, Ian Lepore wrote: > On Mon, 2014-10-06 at 21:41 -0700, Russell Haley wrote: >> Hey, >> >> Okay, I lied about waiting till the weekend. I am looking at the atmel >> files. Should I be replacing the at91 moniker with imx (processor >> class) or mx53 (implementation)? >> >> Thanks, >> >> Russ > > With a quick glance at the manuals, it appears imx51 and imx53 have the > same nand controller hardware, but imx6 is completely different, so > 'imx5' would be the right prefix for file and function/data names. > > That said, I want to point out that there's a huge difference between > the simplistic memory controller for accessing nand in the at91 hardware > and the much more complex nand hardware in the imx5 series. I don't > think you're going to get far by trying to copy the at91 driver. In > fact, I think you're going to find it impossible to make the imx5 BCH > hardware work with the upper layers of the nand software in freebsd > without some serious redesign of the upper layers (and then of course > the associated rewriting of existing low-level nfc drivers). > > It's not that I want to discourage you from trying, I just want to be > realistic here. What you're embarking on isn't a couple days of > converting an existing driver -- in my estimation, you're looking at > weeks of work. I don't mean 3 calendar weeks of a couple hours each > evening hobbyist work, I'm talking hundreds of hours of development > time. The harsh reality is that freebsd doesn't have adequate nand > flash support for modern hardware. We don't even have the framework of > a design that can accomodate things like hardware offload of ECC. > > -- Ian > >