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 755CBC83003 for ; Wed, 29 Apr 2020 09:35:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B87420731 for ; Wed, 29 Apr 2020 09:35:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726447AbgD2Jfg convert rfc822-to-8bit (ORCPT ); Wed, 29 Apr 2020 05:35:36 -0400 Received: from relay1-d.mail.gandi.net ([217.70.183.193]:46009 "EHLO relay1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726366AbgD2Jfg (ORCPT ); Wed, 29 Apr 2020 05:35:36 -0400 X-Originating-IP: 91.224.148.103 Received: from xps13 (unknown [91.224.148.103]) (Authenticated sender: miquel.raynal@bootlin.com) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id 26FB2240016; Wed, 29 Apr 2020 09:35:30 +0000 (UTC) Date: Wed, 29 Apr 2020 11:35:29 +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: <20200429113529.5ddc3ad9@xps13> In-Reply-To: <0e2c9a6a-aa21-7814-9af8-629de6568fab@st.com> 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> 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 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