Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030438AbbD1QTx (ORCPT ); Tue, 28 Apr 2015 12:19:53 -0400 Received: from mail-pa0-f47.google.com ([209.85.220.47]:36651 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030379AbbD1QTw (ORCPT ); Tue, 28 Apr 2015 12:19:52 -0400 MIME-Version: 1.0 In-Reply-To: <20150428140347.GC2798@jcartwri.amer.corp.natinst.com> References: <1427292151-3835-1-git-send-email-richard@nod.at> <1427292151-3835-2-git-send-email-richard@nod.at> <20150427213558.GA22780@bshelton-desktop> <553EB5E4.3050309@nod.at> <20150427232353.GD32500@ld-irv-0074> <20150428032213.GI19571@brian-ubuntu> <20150428140347.GC2798@jcartwri.amer.corp.natinst.com> Date: Tue, 28 Apr 2015 21:49:51 +0530 X-Google-Sender-Auth: rlWQM0iGcF3pi_Z0Y5Rlo5a9_IQ Message-ID: Subject: Re: [PATCH 1/3] mtd: nand: Add on-die ECC support From: punnaiah choudary kalluri To: Josh Cartwright Cc: Brian Norris , Richard Weinberger , Ben Shelton , "linux-mtd@lists.infradead.org" , "linux-kernel@vger.kernel.org" , David Woodhouse , Punnaiah Choudary Kalluri , Boris Brezillon Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2052 Lines: 47 On Tue, Apr 28, 2015 at 7:33 PM, Josh Cartwright wrote: > On Tue, Apr 28, 2015 at 09:14:26AM +0530, punnaiah choudary kalluri wrote: >> On Tue, Apr 28, 2015 at 8:52 AM, Brian Norris wrote: >> > On Tue, Apr 28, 2015 at 08:18:12AM +0530, punnaiah choudary kalluri wrote: >> >> On Tue, Apr 28, 2015 at 4:53 AM, Brian Norris wrote: > [..] >> >> Agree that read_buf need not be returning raw data always including >> >> my new driver for arasan nand flash controller. >> > >> > I agree with that. At the moment, chip->read_buf() really has very >> > driver-specific meaning. Not sure if that's really a good thing, but >> > it's the way things are... >> > >> >> http://lkml.iu.edu/hypermail/linux/kernel/1504.2/00313.html >> > >> > In the half a minute I just spent looking at this (I may review it >> > properly later), I noted a few things: >> > >> > 1. you don't implement ecc.read_page_raw(); this means we'll probably >> > have trouble supporting on-die ECC with your driver, among other things >> >> On-die ECC is optional as long as the controller has better ecc coverage. >> The arasan controller supports up to 24 bit ecc. There is no point to use >> on-die ECC and will always use hw ecc even for On-die ecc devices. > > Maybe this is true of the controller instantiated in the Zynq MPSoC > chips, but the Zynq 7000 series SMC is documented to support only 1-bit > ECC. True. SMC controller in zynq supports only 1 -bit ECC. One can use on-die ECC devices and turn of the controller ECC for better ECC coverage. I am also exploring the options to use these patches with the pl353 driver in a generic way and acceptable to all. Regards, Punnaiah > > (Which is why we're looking at your pl353 driver and this set). > > Josh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/