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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 B5250C433F5 for ; Tue, 28 Aug 2018 13:26:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 62CD320894 for ; Tue, 28 Aug 2018 13:26:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 62CD320894 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728015AbeH1RS2 (ORCPT ); Tue, 28 Aug 2018 13:18:28 -0400 Received: from mail.bootlin.com ([62.4.15.54]:46365 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727716AbeH1RS2 (ORCPT ); Tue, 28 Aug 2018 13:18:28 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 9A6B820797; Tue, 28 Aug 2018 15:26:47 +0200 (CEST) Received: from bbrezillon (AAubervilliers-681-1-53-19.w90-88.abo.wanadoo.fr [90.88.170.19]) by mail.bootlin.com (Postfix) with ESMTPSA id 2B645206A6; Tue, 28 Aug 2018 15:26:47 +0200 (CEST) Date: Tue, 28 Aug 2018 15:26:45 +0200 From: Boris Brezillon To: Liang Yang Cc: Yixun Lan , , Rob Herring , Neil Armstrong , Martin Blumenstingl , Richard Weinberger , , Marek Vasut , Jian Hu , Kevin Hilman , Carlo Caione , , Brian Norris , David Woodhouse , , Jerome Brunet Subject: Re: [RFC PATCH v2 2/2] mtd: rawnand: meson: add support for Amlogic NAND flash controller Message-ID: <20180828152645.457dab5c@bbrezillon> In-Reply-To: References: <20180719094612.5833-1-yixun.lan@amlogic.com> <20180719094612.5833-3-yixun.lan@amlogic.com> <20180801235045.5b4d8211@bbrezillon> <42877a0d-9830-0626-3f64-e49a326eaa3c@amlogic.com> <20180817155608.5929b37a@bbrezillon> <96e538a5-1232-11f2-8b9e-5ddb09dcc2de@amlogic.com> <20180824144810.31c929a5@bbrezillon> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 28 Aug 2018 21:21:48 +0800 Liang Yang wrote: > Hi Boris, > > On 8/24/2018 8:48 PM, Boris Brezillon wrote: > > On Wed, 22 Aug 2018 22:08:42 +0800 > > Liang Yang wrote: > > > >>> You have to wait tWB, that's for sure. > >>> > >> we have a maximum 32 commands fifo. when command is written into > >> NFC_REG_CMD, it doesn't mean that command is executing right now, maybe > >> it is buffering on the queue.Assume one ERASE operation, when 2nd > >> command(0xd0) is written into NFC_REG_CMD and then come into > >> NAND_OP_WAITRDY_INSTR, if I read the RB status by register, it may be > >> wrong because 0xd0 may not being executed. it is unusual unless > >> buffering two many command. > > > > You should flush the queue and wait for it to empty at the end of > > ->exec_op(). > > > >> so it seems that i still need to use nand_soft_waitrdy or wait cmd is > >> executed somewhere. > > > > Don't you have a WAIT_FOR_RB instruction? What is NFC_CMD_RB for? Also, > > NFC_CMD_IDLE seems to allow you to add an arbitrary delay, and that's > > probably what you should use for tWB. > > > > em, I can wait for RB by reading the status from register now. but when > calling nand_soft_waitrdy, i really met a problem. One *jiffies* is > about 4ms. When programming, it pass 1ms to > instr->ctx.waitrdy.timeout_ms and nand_soft_waitrdy will be only one > *jiffies* to reach timeout. And then calling nand_soft_waitrdy maybe at > the tail of 4ms interval, it may only wait 100us and next jiffies > arrive. Is it correct? Hm, no. If you initialize the time you compare to (using time_before() or time_after()) correctly it should not happen. Anyway, I keep thinking this is not how it should be done. Did you try NFC_CMD_RB? Did you ask HW designers what it was created for?