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 40271C83007 for ; Tue, 28 Apr 2020 07:50:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27FB720730 for ; Tue, 28 Apr 2020 07:50:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726636AbgD1Huc (ORCPT ); Tue, 28 Apr 2020 03:50:32 -0400 Received: from mga07.intel.com ([134.134.136.100]:36197 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726279AbgD1Huc (ORCPT ); Tue, 28 Apr 2020 03:50:32 -0400 IronPort-SDR: 9XVIGbg3QXDVa4PczJ5s3RBRPDgtgE/lP2MapDeKAfRRYwAOAwdsx6tIXzWhjaJ3OetdNyqu7W NFVCsrNFJFDg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2020 00:50:15 -0700 IronPort-SDR: Awb1bZFMitFdF85kM6dXZn8cxfRuQgpSwj/DQ+BOpdnC/L1goQEp2Qap4LoAD1NZkgDzGVUWrH 3V9iLhcCGMGA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,327,1583222400"; d="scan'208";a="367419227" Received: from linux.intel.com ([10.54.29.200]) by fmsmga001.fm.intel.com with ESMTP; 28 Apr 2020 00:50:14 -0700 Received: from [10.214.149.60] (vramuthx-MOBL1.gar.corp.intel.com [10.214.149.60]) by linux.intel.com (Postfix) with ESMTP id 7E9755807CA; Tue, 28 Apr 2020 00:50:07 -0700 (PDT) Reply-To: vadivel.muruganx.ramuthevar@linux.intel.com Subject: Re: [PATCH v3 2/2] mtd: rawnand: Add NAND controller support on Intel LGM SoC To: Miquel Raynal Cc: Boris Brezillon , linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, cheol.yong.kim@intel.com, hauke.mehrtens@intel.com, qi-ming.wu@intel.com, vigneshr@ti.com, arnd@arndb.de, richard@nod.at, brendanhiggins@google.com, linux-mips@vger.kernel.org, robh+dt@kernel.org, tglx@linutronix.de, masonccyang@mxic.com.tw, andriy.shevchenko@intel.com References: <20200423162113.38055-1-vadivel.muruganx.ramuthevar@linux.intel.com> <20200423162113.38055-3-vadivel.muruganx.ramuthevar@linux.intel.com> <20200424183612.4cfdbb6a@collabora.com> <20200427175127.0518c193@xps13> <20200428082759.25065146@collabora.com> <38334812-21b9-5b2c-db84-01c9eacc84d0@linux.intel.com> <20200428084704.5e04232a@collabora.com> <20200428094049.3c0d4730@xps13> From: "Ramuthevar, Vadivel MuruganX" Message-ID: <3ebc42d9-f8a8-0764-ff7f-82beeb0b5bb7@linux.intel.com> Date: Tue, 28 Apr 2020 15:50:06 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200428094049.3c0d4730@xps13> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Miquel, On 28/4/2020 3:40 pm, Miquel Raynal wrote: > Hi Vadivel MuruganX, > > "Ramuthevar, Vadivel MuruganX" > wrote on Tue, 28 Apr 2020 > 14:50:35 +0800: > >> Hi Boris, >> >> On 28/4/2020 2:47 pm, Boris Brezillon wrote: >>> On Tue, 28 Apr 2020 14:40:58 +0800 >>> "Ramuthevar, Vadivel MuruganX" >>> wrote: >>> >>>> Hi Boris, >>>> >>>> On 28/4/2020 2:27 pm, Boris Brezillon wrote: >>>>> On Tue, 28 Apr 2020 14:17:30 +0800 >>>>> "Ramuthevar, Vadivel MuruganX" >>>>> wrote: >>>>> >>>> Hi Miquel, >>>>>> >>>>>> Thank you very much for the review comments and your time... >>>>>> >>>>>> On 27/4/2020 11:51 pm, Miquel Raynal wrote: >>>>>>> Hi Ramuthevar, >>>>>>> >>>>>>> +static int ebu_nand_probe(struct platform_device *pdev) >>>>>>>>> +{ >>>>>>>>> + struct device *dev = &pdev->dev; >>>>>>>>> + struct ebu_nand_controller *ebu_host; >>>>>>>>> + struct nand_chip *nand; >>>>>>>>> + phys_addr_t nandaddr_pa; >>>>>>>>> + struct mtd_info *mtd; >>>>>>>>> + struct resource *res; >>>>>>>>> + int ret; >>>>>>>>> + u32 cs; >>>>>>>>> + >>>>>>>>> + ebu_host = devm_kzalloc(dev, sizeof(*ebu_host), GFP_KERNEL); >>>>>>>>> + if (!ebu_host) >>>>>>>>> + return -ENOMEM; >>>>>>>>> + >>>>>>>>> + ebu_host->dev = dev; >>>>>>>>> + nand_controller_init(&ebu_host->controller); >>>>>>>>> + >>>>>>>>> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ebunand"); >>>>>>>>> + ebu_host->ebu_addr = devm_ioremap_resource(&pdev->dev, res); >>>>>>>>> + if (IS_ERR(ebu_host->ebu_addr)) >>>>>>>>> + return PTR_ERR(ebu_host->ebu_addr); >>>>>>>>> + >>>>>>>>> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "hsnand"); >>>>>>>>> + ebu_host->nand_addr = devm_ioremap_resource(&pdev->dev, res); >>>>>>>>> + if (IS_ERR(ebu_host->nand_addr)) >>>>>>>>> + return PTR_ERR(ebu_host->nand_addr); >>>>>>>>> + >>>>>>>>> + ret = device_property_read_u32(dev, "nand,cs", &cs); >>>>>>>> >>>>>>>> CS ids should be encoded in the reg property (see [1]). >>>>>>> >>>>>>> Is it your choice to only support a single CS or is it actually a >>>>>>> controller limitation? >>>>>> >>>>>> Yes , its controller limitation to support only one CS >>>>> >>>>> I'm pretty sure that's not true, otherwise you wouldn't have to select >>>>> the CS you want to use :P. >>>> >>>> At a time it supports only one chip select. >>> >>> Yes, like 99% of the NAND controllers, but that doesn't mean you can't >>> support multi-CS chips. All you have to do is attach an array of >>> ebu_nand_cs to your ebu_nand_chip (as done in the atmel driver I >>> pointed to). nand_operation.cs tells you which CS (index in your >>> ebu_nand_cs array) a specific operation is targeting, and you can pick >>> the right MMIO range/reg value based on that. >> >> Agreed, sure I will add that and update next series of patches . > > There are also many other places where you assume blindly that there > is only one CS. You can check the Atmel NAND controller driver as Boris > said and we will probably propose more little changes to be more > generic. since LGM EBU_NAND controller supports only one chip select at a time, so assumed like that, will change as generic way if consider like more chip select supports, Thanks! Sure , I will do the changes as per your review comments. > > Thanks, > Miquèl >