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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 9BE8DC433DB for ; Fri, 12 Mar 2021 13:33:59 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 30E3560190 for ; Fri, 12 Mar 2021 13:33:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 30E3560190 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=walle.cc Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-ID:References:In-Reply-To:Subject:Cc:To:From :Date:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Buu32KJjaKyUNzLI0qkPY5lQilGyhz0QQ3M0F+99ITM=; b=c/dVYORhgrFRadx2EYBTscBvt rDk+zFDb4q5CX+ocF1s/MLvVBK3KP2Ypgd41bcTKOuCPEbknmfvPooShhGJ7xXscIb4ZOl2UiF6Xu cLu8aUUUoZEVAWARaBZO5tD93AjAw7XS+0J29XViqUUsRqgvXgXz8oLgw9ayefATs9YIDjnzKkRo4 Mcj92xJ66qf/SLqu3cAnUypKoX5N+LORk7+otVaDZfaFYm2/A7WDDlHX7gSeo9DI+FYMm29m6v3Ci QlDZnIWm/4MtTosntf3RjOprgD3muxGRjXD+87HtVOEyXAS2LcZLfnfazh2cmN1b2u7UpdAfrbuR0 DOmS8QeEw==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKhu5-00BXSC-5w; Fri, 12 Mar 2021 13:32:33 +0000 Received: from ssl.serverraum.org ([2a01:4f8:151:8464::1:2]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lKhtx-00BXRO-V3; Fri, 12 Mar 2021 13:32:29 +0000 Received: from ssl.serverraum.org (web.serverraum.org [172.16.0.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id 438F722238; Fri, 12 Mar 2021 14:32:25 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1615555945; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QBuZP8POWp3qMMHBSO5zfPwntXaxLE+5SncR7mrkwkQ=; b=fVeBkdcbfb0c7Z3025M6QUtKCnZBa2aNX05py5QmSYQTSEaWsyniqyN9M5FHUL77xqM7xq FzoedG7HmpzUT5MtJ1BsZSmiUozPbYcGeQxArBa9KJzjjwsUR1CRbDuLYSTz2W1mxDlWG3 oNTTVz+JnDS/UK8Y6Ravou9ofFt/t6Q= MIME-Version: 1.0 Date: Fri, 12 Mar 2021 14:32:25 +0100 From: Michael Walle To: Pratyush Yadav Cc: Nishanth Menon , Tero Kristo , Rob Herring , Tudor Ambarus , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Mark Brown , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-spi@vger.kernel.org, Lokesh Vutla Subject: Re: [RFC PATCH 0/6] spi: Add OSPI PHY calibration support for spi-cadence-quadspi In-Reply-To: <20210311191216.7363-1-p.yadav@ti.com> References: <20210311191216.7363-1-p.yadav@ti.com> User-Agent: Roundcube Webmail/1.4.11 Message-ID: X-Sender: michael@walle.cc X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210312_133226_551402_952C8D2E X-CRM114-Status: GOOD ( 16.06 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Am 2021-03-11 20:12, schrieb Pratyush Yadav: > The main problem here is telling the controller where to find the > pattern and how to read it. This RFC uses nvmem cells which point to a > fixed partition containing the data to do the reads. It depends on [0] > and [1]. > > The obvious problem with this is it won't work when the partitions are > defined via command line. I don't see any good way to add nvmem cells > to > command line partitions. I would like some help or ideas here. We don't > necessarily have to use nvmem either. Any way that can cleanly and > consistently let the controller find out where the pattern is stored is > good. The NXP LS1028A SoC has a similar calibration (although there its done in hardware it seems) and there the datasheet mentions there are flash devices which supports a preamble before a read function. The preamble is then some kind of learning pattern. Did you see a flash which actually supports that in the wild? I can't find any publicly available datasheets of 8bit I/O SPI NOR flashes. -michael _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel