From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 15.mo4.mail-out.ovh.net ([91.121.62.11] helo=mo4.mail-out.ovh.net) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1W3Tsl-0005er-Ni for linux-mtd@lists.infradead.org; Wed, 15 Jan 2014 17:04:02 +0000 Received: from mail414.ha.ovh.net (b6.ovh.net [213.186.33.56]) by mo4.mail-out.ovh.net (Postfix) with SMTP id BFE0110107E1 for ; Wed, 15 Jan 2014 18:07:40 +0100 (CET) Message-ID: <52D6BF45.80407@overkiz.com> Date: Wed, 15 Jan 2014 18:03:01 +0100 From: boris brezillon MIME-Version: 1.0 To: Jason Gunthorpe Subject: Re: [RFC PATCH 3/9] of: mtd: add NAND timings retrieval support References: <1389190924-26226-1-git-send-email-b.brezillon@overkiz.com> <1389190924-26226-4-git-send-email-b.brezillon@overkiz.com> <20140108183418.GA12358@obsidianresearch.com> <52CDA032.3010804@overkiz.com> <20140108191339.GB12358@obsidianresearch.com> <52CE5F82.6070802@overkiz.com> <20140109173505.GB8899@obsidianresearch.com> <52D6A48D.4080302@overkiz.com> In-Reply-To: <52D6A48D.4080302@overkiz.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Cc: devicetree@vger.kernel.org, Russell King , linux-doc@vger.kernel.org, dev@linux-sunxi.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Rob Landley , Grant Likely , Maxime Ripard , David Woodhouse , linux-arm-kernel@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 15/01/2014 16:09, boris brezillon wrote: > Hello Jason, > > On 09/01/2014 18:35, Jason Gunthorpe wrote: >> On Thu, Jan 09, 2014 at 09:36:18AM +0100, boris brezillon wrote: >> >>>> You might want to check if you can boil down the DT timings from the >>>> huge list to just an ONFI mode number.. >>> Sure, but the sunxi driver needs at least 19 of them... >> So does mvebu's NAND driver.. >> >> What I ment was you could have a >> >> onfi,nand-timing-mode = 0 >> >> in the DT. Each of the modes defines all ~19 parameters, higher modes >> are faster. >> >> Pick a mode value that fits all the parameters of the connected >> non-ONFI flash. >> >> This would be instead of defining each parameter >> individually.. Provide some helpers to convert from a onfi mode number >> to all the onfi defined timing parameters so that drivers can >> configure the HW.. > > Are you suggesting we should provide a function that converts these > modes into a nand_timings struct, or just use the timing modes and > let the NAND controller drivers configure its IP accordingly ? > > I found the ONFI timing tables in this document: > > www.*onfi*.org/~/media/*ONFI*/specs/*onfi*_3_1_spec.pdf‎ (chapter 4.16). > > I suppose my nand_timings struct should use the names described > page 110-111 (at least if we decide to use nand_timings and not > nand_timing_modes), right ? After taking a closer look at this document, the only parameter available in my nand_timings struct that is not defined in the standard is tR_max (data transfer from cell to register). And the ONFI standard defines 4 more timings: - tCEA_max - tCEH_min - tFEAT_max - tITC_max > > Best Regards, > > Boris > >> >> Jason >