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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 1CCB2C8300A for ; Wed, 29 Apr 2020 10:27:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04BC32073E for ; Wed, 29 Apr 2020 10:27:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726669AbgD2K1Q convert rfc822-to-8bit (ORCPT ); Wed, 29 Apr 2020 06:27:16 -0400 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:47875 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726516AbgD2K1P (ORCPT ); Wed, 29 Apr 2020 06:27:15 -0400 X-Originating-IP: 91.224.148.103 Received: from xps13 (unknown [91.224.148.103]) (Authenticated sender: miquel.raynal@bootlin.com) by relay6-d.mail.gandi.net (Postfix) with ESMTPSA id 91395C0002; Wed, 29 Apr 2020 10:27:11 +0000 (UTC) Date: Wed, 29 Apr 2020 12:27:10 +0200 From: Miquel Raynal To: Christophe Kerello Cc: , , , , , , , , , , Subject: Re: [PATCH v2 06/12] mtd: rawnand: stm32_fmc2: use FMC2_TIMEOUT_MS for timeouts Message-ID: <20200429122710.291d54ff@xps13> In-Reply-To: References: <1586966256-29548-1-git-send-email-christophe.kerello@st.com> <1586966256-29548-7-git-send-email-christophe.kerello@st.com> <20200427202212.0235d987@xps13> <0e2c9a6a-aa21-7814-9af8-629de6568fab@st.com> <20200429113529.5ddc3ad9@xps13> <20200429120632.7bce63e6@xps13> Organization: Bootlin X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Christophe, Christophe Kerello wrote on Wed, 29 Apr 2020 12:13:18 +0200: > On 4/29/20 12:06 PM, Miquel Raynal wrote: > > Hi Christophe, > > > > Christophe Kerello wrote on Wed, 29 Apr > > 2020 11:41:44 +0200: > > > >> On 4/29/20 11:35 AM, Miquel Raynal wrote: > >>> Hi Christophe, > >>> > >>> Christophe Kerello wrote on Wed, 29 Apr > >>> 2020 11:27:43 +0200: > >>> >>>> Hi Miquèl, > >>>> > >>>> On 4/27/20 8:22 PM, Miquel Raynal wrote: > >>>>> Hi Christophe, > >>>>> > >>>>> Christophe Kerello wrote on Wed, 15 Apr > >>>>> 2020 17:57:30 +0200: > >>>>> >>>> This patch removes the constant FMC2_TIMEOUT_US. > >>>>>> FMC2_TIMEOUT_MS is set to 5 seconds and this constant is used > >>>>>> each time that we need to wait (except when the timeout value > >>>>>> is set by the framework) > >>>>>> > >>>>>> Signed-off-by: Christophe Kerello > >>>>>> --- > >>>>>> drivers/mtd/nand/raw/stm32_fmc2_nand.c | 11 +++++------ > >>>>>> 1 file changed, 5 insertions(+), 6 deletions(-) > >>>>>> > >>>>>> diff --git a/drivers/mtd/nand/raw/stm32_fmc2_nand.c b/drivers/mtd/nand/raw/stm32_fmc2_nand.c > >>>>>> index ab53314..f159c39 100644 > >>>>>> --- a/drivers/mtd/nand/raw/stm32_fmc2_nand.c > >>>>>> +++ b/drivers/mtd/nand/raw/stm32_fmc2_nand.c > >>>>>> @@ -37,8 +37,7 @@ > >>>>>> /* Max ECC buffer length */ > >>>>>> #define FMC2_MAX_ECC_BUF_LEN (FMC2_BCHDSRS_LEN * FMC2_MAX_SG) > >>>>>> >> -#define FMC2_TIMEOUT_US 1000 > >>>>>> -#define FMC2_TIMEOUT_MS 1000 > >>>>>> +#define FMC2_TIMEOUT_MS 5000 > >>>>>> >> /* Timings */ > >>>>>> #define FMC2_THIZ 1 > >>>>>> @@ -525,9 +524,9 @@ static int stm32_fmc2_ham_calculate(struct nand_chip *chip, const u8 *data, > >>>>>> u32 sr, heccr; > >>>>>> int ret; > >>>>>> >> - ret = readl_relaxed_poll_timeout(fmc2->io_base + FMC2_SR, > >>>>>> - sr, sr & FMC2_SR_NWRF, 10, > >>>>>> - FMC2_TIMEOUT_MS); > >>>>>> + ret = readl_relaxed_poll_timeout_atomic(fmc2->io_base + FMC2_SR, > >>>>>> + sr, sr & FMC2_SR_NWRF, 1, > >>>>>> + 1000 * FMC2_TIMEOUT_MS); > >>>>> > >>>>> Is the _atomic suffix needed here? If yes it would deserve a separate > >>>>> patch with Fixes/Stable tags. > >>>>> >> > >>>> I have currently not seen any issues. So, I will remove this modification as we will move to regmap_read_poll_timeout in patch 10. > >>>> >>>>>> if (ret) { > >>>>>> dev_err(fmc2->dev, "ham timeout\n"); > >>>>>> return ret; > >>>>>> @@ -1315,7 +1314,7 @@ static int stm32_fmc2_waitrdy(struct nand_chip *chip, unsigned long timeout_ms) > >>>>>> /* Check if there is no pending requests to the NAND flash */ > >>>>>> if (readl_relaxed_poll_timeout_atomic(fmc2->io_base + FMC2_SR, sr, > >>>>>> sr & FMC2_SR_NWRF, 1, > >>>>>> - FMC2_TIMEOUT_US)) > >>>>>> + 1000 * FMC2_TIMEOUT_MS)) > >>>>>> dev_warn(fmc2->dev, "Waitrdy timeout\n"); > >>>>>> >> /* Wait tWB before R/B# signal is low */ > >>>>> > >>>>> You change the timeouts from 1ms to 5s. > >>>>> > >>>>> Maybe 5s is a little bit too much IMHO but we don't really care as this > >>>>> is a timeout. However 1ms is tight. If you are changing this value > >>>>> because it triggers error (eg. when the machine is loaded), then it is > >>>>> a fix and should appear like it. > >>>>> > >>>>> Thanks, > >>>>> Miquèl > >>>>> >> > >>>> No errors currently happens. > >>>> During our stress tests, in a overloaded system, we have seen that we could be close to 1 second, even if we never met this value. > >>>> So, to be safe, I have set this timeout to 5 seconds. > >>>> As it is just a timeout value, I have not seen any side effect. > >>>> I am using the same timeout constant to avoid to have one timeout per cases. > >>> > >>> Something is wrong in my mind: > >>> You say you observe delays of almost up to 1 second, but the polling > >>> currently happens on 1000 us = 1ms, either you had timeouts or I > >>> misread something? > >>> > >>> Thanks, > >>> Miquèl > >>> >> > >> Hi Miquèl, > >> > >> My fault. For this polling, we never met 1 ms. > >> The 1 second observed was on the sequencer when we read/write a page (as it the same timeout value that is used) > > > > OK I get it. So perhaps you can give these details in the commit log to > > explain why you use 5 seconds instead of one. > > > > Thanks, > > Miquèl > > > > Hi Miquèl, > > A proposal could also be to split this patch: > - a first patch that is using only one timeout value. > - a second patch that is increasing the value to 5 seconds. > > Regards, > Christophe Kerello. Given the situation, both are fine as long as everything is clearly explained in the commit log :) Thanks, Miquèl