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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,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 01B40C3F2D1 for ; Wed, 4 Mar 2020 17:25:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C34FF2073B for ; Wed, 4 Mar 2020 17:25:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="EbNEl+wX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729857AbgCDRZ6 (ORCPT ); Wed, 4 Mar 2020 12:25:58 -0500 Received: from hqnvemgate25.nvidia.com ([216.228.121.64]:12891 "EHLO hqnvemgate25.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726561AbgCDRZ6 (ORCPT ); Wed, 4 Mar 2020 12:25:58 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 04 Mar 2020 09:25:16 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 04 Mar 2020 09:25:56 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 04 Mar 2020 09:25:56 -0800 Received: from [10.2.174.88] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 4 Mar 2020 17:25:56 +0000 Subject: Re: LKFT: arm x15: mmc1: cache flush error -110 From: Sowjanya Komatineni To: Ulf Hansson CC: Jon Hunter , Bitan Biswas , Adrian Hunter , Naresh Kamboju , Jens Axboe , Alexei Starovoitov , linux-block , , open list , "linux-mmc@vger.kernel.org" , Arnd Bergmann , John Stultz , Faiz Abbas , Thierry Reding , Anders Roxell , Kishon References:

<6523119a-50ac-973a-d1cd-ab1569259411@nvidia.com>

<0963b60f-15e7-4bc6-10df-6fc8003e4d42@nvidia.com> <34fd84d7-387b-b6f3-7fb3-aa490909e205@ti.com> <5e9b5646-bd48-e55b-54ee-1c2c41fc9218@nvidia.com> <757853cf-987e-f6b6-9259-b4560a031692@nvidia.com> Message-ID: Date: Wed, 4 Mar 2020 09:26:06 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Content-Language: en-US DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1583342716; bh=tE0i0J794EBd/p1vk3ldDjHW0EdV4i7rVUVo1KD2iw8=; h=X-PGP-Universal:Subject:From:To:CC:References:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Transfer-Encoding: Content-Language; b=EbNEl+wX8/kWBK16Wny3dqqEwrjI1jVrdgloyfXYW4pnsKK4fX0SZnioC+nm2K1gA qlrpZPpXyRwY1wpr+9ZhdHX4qD6eegiHLNDLGkN8VimEn5O5aQqa11n71G2UGA12kL y2Xos/Wlr8epNasiR/ClAM3RNuzNZEfvLZ/F6lbv43p7kRG04YfL9eRX7Cq0RYYPLK LsmkNdppm6bhF1fVlkPCvz2i+7moVXdNpVJlmsZflH4XM+xvAQsPDa+BVxYcUBNOPz MfYM/SJ/Gzg7T0GOssZKRj7Zbo7iEN+swUytxinh/cfQgBo3oSoBQq1J9ToR5CFK4V YJ/pF4WLOqbyw== Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 3/4/20 9:21 AM, Sowjanya Komatineni wrote: > > On 3/4/20 8:56 AM, Sowjanya Komatineni wrote: >> >> On 3/4/20 2:18 AM, Ulf Hansson wrote: >>> External email: Use caution opening links or attachments >>> >>> >>> [...] >>> >>>> So, from my side, me and Anders Roxell, have been collaborating on >>>> testing the behaviour on a TI Beagleboard x15 (remotely with limited >>>> debug options), which is using the sdhci-omap variant. I am trying to >>>> get hold of an Nvidia jetson-TX2, but not found one yet. These are the >>>> conclusions from the observed behaviour on the Beagleboard for the >>>> CMD6 cache flush command. >>>> >>>> First, the reported host->max_busy_timeout is 2581 (ms) for the >>>> sdhci-omap driver in this configuration. >>>> >>>> 1. As we all know by now, the cache flush command (CMD6) fails with >>>> -110 currently. This is when MMC_CACHE_FLUSH_TIMEOUT_MS is set to 30 * >>>> 1000 (30s), which means __mmc_switch() drops the MMC_RSP_BUSY flag >>>> from the command. >>>> >>>> 2. Changing the MMC_CACHE_FLUSH_TIMEOUT_MS to 2000 (2s), means that >>>> the MMC_RSP_BUSY flag becomes set by __mmc_switch, because of the >>>> timeout_ms parameter is less than max_busy_timeout (2000 < 2581). >>>> Then everything works fine. >>>> >>>> 3. Updating the code to again use 30s as the >>>> MMC_CACHE_FLUSH_TIMEOUT_MS, but instead forcing the MMC_RSP_BUSY to be >>>> set, even when the timeout_ms becomes greater than max_busy_timeout. >>>> This also works fine. >>>> >>>> Clearly this indicates a problem that I think needs to be addressed in >>>> the sdhci driver. However, of course I can revert the three discussed >>>> patches to fix the problem, but that would only hide the issues and I >>>> am sure we would then get back to this issue, sooner or later. >>>> >>>> To fix the problem in the sdhci driver, I would appreciate if someone >>>> from TI and Nvidia can step in to help, as I don't have the HW on my >>>> desk. >>>> >>>> Comments or other ideas of how to move forward? >>> [...] >>> >>>> Hi Ulf, >>>> >>>> I could repro during suspend on Jetson TX1/TX2 as when it does mmc=20 >>>> flush cache. >>> Okay, great. >>> >>>> >>>> Timeout I see is for switch status CMD13 after sending CMD6 as=20 >>>> device side CMD6 is still inflight while host sends CMD13 as we are=20 >>>> using R1 response type with timeout_ms changes to 30s. >>>> >>>> >>>> >>>> Earlier we used timeout_ms of 0 for CMD6 flush cache, and with it=20 >>>> uses R1B response type and host will wait for busy state followed=20 >>>> by response from device for CMD6 and then data lines go High. >>>> >>>> >>>> >>>> Now with timeout_ms changed to 30s, we use R1 response and SW waits=20 >>>> for busy by checking for DAT0 line to go High. >>> If I understand correctly, because of the timeout now set to 30s, >>> MMC_RSP_BUSY becomes disabled in __mmc_switch() for your case in >>> sdhci-tegra as well? >> Yes >>> >>> In other words, mmc_poll_for_busy() is being called, which in your >>> case means the ->card_busy() host ops (set to sdhci_card_busy() in >>> your case) will be invoked to wait for the card to stop signal busy on >>> DAT0. >>> >>> This indicates to me, that the ->card_busy() ops returns zero to >>> inform that the card is *not* busy, even if the card actually signals >>> busy? Is that correct? >> Yes >>> >>>> >>>> >>>> With R1B type, host design after sending command at end of=20 >>>> completion after end bit waits for 2 cycles for data line to go low=20 >>>> (busy state from device) and waits for response cycles after which=20 >>>> data lines will go back high and then we issue switch status CMD13. >>>> >>>> >>>> >>>> With R1 type, host after sending command and at end of completion=20 >>>> after end bit, DATA lines will go high immediately as its R1 type=20 >>>> and switch status CMD13 gets issued but by this time it looks like=20 >>>> CMD6 on device side is still in flight for sending status and data. >>> So, yes, using R1 instead of R1B triggers a different behaviour, but >>> according to the eMMC spec it's perfectly allowed to issue a CMD13 >>> even if the card signals busy on DAT0. The CMD13 is not using the DATA >>> lines, so this should work. >>> >>> If I understand correctly, your driver (and controller?) has issues >>> with coping with this scenario. Is it something that can be fixed? >>> >>>> >>>> 30s timeout is the wait time for data0 line to go high and=20 >>>> mmc_busy_status will return success right away with R1 response=20 >>>> type and SW sends switch status CMD13 but during that time on=20 >>>> device side looks like still processing CMD6 as we are not waiting=20 >>>> for enough time when we use R1 response type. >>> Right, as stated above, isn't sdhci_card_busy() working for your case? >>> Can we fix it? >> >> sdhci_card_busy() returned 0 indicating its not busy. >> >> Based on our host design, When CMD6 is issued with R1 type, we=20 >> program it as NO_RESPONSE and with this command complete interrupt=20 >> happens right at end bit of command and there will be no transfer=20 >> complete interrupt. > *[Correction] Based on our host design, When CMD6 is issued with R1=20 > type as we program it as NO_RESPONSE and with this command complete=20 > interrupt happens right at end bit of command and there will be no=20 > transfer complete interrupt. Sorry to correct wordings, I meant sdhci driver programs response type=20 as NO_RESPONSE for CMD6. When CMD6 is issued with R1 type and as NO_RESPONSE, Based on our host=20 design=C2=A0 command complete interrupt happens right at end bit of command= =20 and there will be no transfer complete interrupt. >> >> When CMD6 is issued with R1B type, we program is as R1B RESP_SHORT=20 >> and with this command complete is end bit of device resp and transfer=20 >> complete interrupt will be when DAT0 LOW -> HIGH. >> >> Regardless of R1/R1B, device side CMD6 will always have busy state on=20 >> D0 and response on CMD lines. >> >> There will be 2 clock cycles period after sending CMD6 for device to=20 >> send busy state on data0. >> >> In case of R1 type, after sending command DAT will stay high and=20 >> looks like we are polling for busy early before busy state has=20 >> started and sending CMD13 while device is busy and sending response=20 >> on CMD line is causing timeout. >> >> Probably with this specific case of CMD6 with R1 type, to wait for=20 >> card busy we should poll for DAT0 to go Low first and then to go High?? >> >>> >>>> >>>> >>>> >>>> Actually we always use R1B with CMD6 as per spec. >>> I fully agree that R1B is preferable, but it's not against the spec to >>> send CMD13 to poll for busy. >>> >>> Moreover, we need to cope with the scenario when the host has >>> specified a maximum timeout that isn't sufficiently long enough for >>> the requested operation. Do you have another proposal for how to >>> manage this, but disabling MMC_RSP_BUSY? >>> >>> Let's assume you driver would get a R1B for the CMD6 (we force it), >>> then what timeout would the driver be using if we would set >>> cmd.busy_timeout to 30ms? >>> >>> Kind regards >>> Uffe