From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69CCEC2BB85 for ; Fri, 17 Apr 2020 07:54:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F38D12137B for ; Fri, 17 Apr 2020 07:54:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729547AbgDQHyJ (ORCPT ); Fri, 17 Apr 2020 03:54:09 -0400 Received: from mga06.intel.com ([134.134.136.31]:59833 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728330AbgDQHyH (ORCPT ); Fri, 17 Apr 2020 03:54:07 -0400 IronPort-SDR: aCy4eCkLjWRCgjIIldCeLSTyatESlxvDUWXbdmdX05VFd3WeIi3sxXENzJ3T2OuZflHs6f0Zzw w7pZyL7Dy4aQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Apr 2020 00:54:06 -0700 IronPort-SDR: Px9yLcqRBmj56jfaP+rRX6jDKBHOo8gm5ANSSCS9GGBKdDOvt1ZF+D+XGMGxZ8l6+ldxjV2EUs qv+2ehWgYF2A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,394,1580803200"; d="scan'208";a="299548159" Received: from linux.intel.com ([10.54.29.200]) by FMSMGA003.fm.intel.com with ESMTP; 17 Apr 2020 00:54:05 -0700 Received: from [10.255.156.142] (vramuthx-MOBL1.gar.corp.intel.com [10.255.156.142]) by linux.intel.com (Postfix) with ESMTP id 154325802C9; Fri, 17 Apr 2020 00:54:00 -0700 (PDT) Subject: Re: [PATCH v1 2/2] mtd: rawnand: Add NAND controller support on Intel LGM SoC To: Boris Brezillon Cc: Martin Blumenstingl , anders.roxell@linaro.org, andriy.shevchenko@intel.com, arnd@arndb.de, brendanhiggins@google.com, cheol.yong.kim@intel.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, masonccyang@mxic.com.tw, miquel.raynal@bootlin.com, piotrs@cadence.com, qi-ming.wu@intel.com, richard@nod.at, robh+dt@kernel.org, tglx@linutronix.de, vigneshr@ti.com References: <20200414022433.36622-3-vadivel.muruganx.ramuthevar@linux.intel.com> <20200415220533.733834-1-martin.blumenstingl@googlemail.com> <20200416113822.2ef326cb@collabora.com> <18568cf6-2955-472e-7b68-eb35e654a906@linux.intel.com> <20200416122619.2c481792@collabora.com> <20200416131725.51259573@collabora.com> <20200416135711.039ba85c@collabora.com> <003fa549-08c5-5867-2b02-54b483c16465@linux.intel.com> <20200417090234.059418f6@collabora.com> From: "Ramuthevar, Vadivel MuruganX" Message-ID: Date: Fri, 17 Apr 2020 15:53:59 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200417090234.059418f6@collabora.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Boris, On 17/4/2020 3:02 pm, Boris Brezillon wrote: > On Fri, 17 Apr 2020 13:21:39 +0800 > "Ramuthevar, Vadivel MuruganX" > wrote: > >> Hi Boris, >> >> On 16/4/2020 7:57 pm, Boris Brezillon wrote: >>> On Thu, 16 Apr 2020 19:38:03 +0800 >>> "Ramuthevar, Vadivel MuruganX" >>> wrote: >>> >>>> On 16/4/2020 7:17 pm, Boris Brezillon wrote: >>>>> On Thu, 16 Apr 2020 18:40:53 +0800 >>>>> "Ramuthevar, Vadivel MuruganX" >>>>> wrote: >>>>> >>>>>>>>> we'll be happy to have one more of the existing driver converted to >>>>>>>>> ->exec_op() ;-). >>>>>>>> I have completely adapted to ->exec_op() hook up to replace the legacy >>>>>>>> call-back. >>>>>>> I suspect porting what you've done to the xway driver shouldn't be too >>>>>>> complicated. >>>>>> Not ported from xway_nand.c driver , we have developed from the scratch >>>>>> to make it work on >>>>>> Intel LGM SoC , it's new x86 ATOM based SoC, IP itself completely >>>>>> different and most of the registers won't match. >>>>>> if we port then it would be ugly and also what are the problem may occur >>>>>> we do not know. >>>>> Sorry but IMO they look similar enough to try to merge them. >>>> Thanks! Boris, need suggestion from you since you are maintainer and >>>> also expertise on mtd-subsystem. >>> I *was* the maintainer :). >>> >>>> There are different features involved and lines of code is more, if we >>>> add new driver patches over xway-nand driver >>> How about retro-fitting the xway logic into your driver then? I mean, >>> adding a 100 lines of code to your driver to get rid of the 500+ lines >>> we have in xway_nand.c is still a win. >>> >>>> is completely looks ugly and it may disturb the existing functionality >>>> as well since we don't have platform to validate:'(. >>> How ugly? Can you show us? Maybe we can come with a solution to make it >>> less ugly. >>> >>> As for the testing part, there are 4 scenarios: >>> >>> 1/ Your changes work perfectly fine on older platforms. Yay \o/! >>> 2/ You break the xway driver and existing users notice it before this >>> series gets merged. Now you found someone to validate your changes. >>> 3/ You break the xway driver and none of the existing users notice it >>> before the driver is merged, but they notice it afterwards. Too bad >>> this happened after we've merged the driver, but now you've found >>> someone to help you fix the problem :P. >>> 4/ You break things for old platforms but no one ever complains about >>> it, either because there's no users left or because they never >>> update their kernels. In any case, that's no longer your problem. >>> Someone will remove those old platforms one day and get rid of the >>> unneeded code in the NAND driver. >>> >>> What's more likely to happen is #3 or #4, and I think the NAND >>> maintainer would be fine with both. >>> >>> Note that the NAND subsystem is full of unmaintained legacy drivers, so >>> every time we see someone who could help us get rid or update one of >>> them we have to take this opportunity. >> Agreed!, Thank you very much for the suggestions and clear inputs. >> To proceed further, can you please share your inputs to dividing the tasks >> and patches to be sent if possible. > Let's start with the new version you were about to post. We'll see how > we can merge both drivers based on that. Thank you very much for the review comments and inputs , will post the patches soon. Regards Vadivel