From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrzej Hajda Subject: Re: [RFC PATCH] mmc: dw_mmc: add status check before clock update Date: Fri, 13 Feb 2015 09:13:47 +0100 Message-ID: <54DDB23B.3050407@samsung.com> References: <1423572711-13787-1-git-send-email-a.hajda@samsung.com> <1423578559-27947-1-git-send-email-a.hajda@samsung.com> <54DB09EA.30602@samsung.com> <54DB13A7.8090101@samsung.com> <54DB1B78.1010709@samsung.com> <54DDA825.1080509@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout4.w1.samsung.com ([210.118.77.14]:27257 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751792AbbBMINz (ORCPT ); Fri, 13 Feb 2015 03:13:55 -0500 Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout4.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NJP00H8RB1SFC40@mailout4.w1.samsung.com> for linux-mmc@vger.kernel.org; Fri, 13 Feb 2015 08:17:52 +0000 (GMT) In-reply-to: <54DDA825.1080509@samsung.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Jaehoon Chung , Javier Martinez Canillas Cc: Alim Akhtar , "linux-mmc@vger.kernel.org" , Seungwon Jeon , Chris Ball , Ulf Hansson , Marek Szyprowski , Kyungmin Park On 02/13/2015 08:30 AM, Jaehoon Chung wrote: > Hi, Andrzej. > > On 02/13/2015 01:53 AM, Javier Martinez Canillas wrote: >> Hello Andrzej, >> >> On Wed, Feb 11, 2015 at 10:06 AM, Andrzej Hajda wrote: >>> On 02/11/2015 09:32 AM, Jaehoon Chung wrote: >>>> On 02/11/2015 04:51 PM, Andrzej Hajda wrote: >>>>> Hi, >>>>> >>>>> Thanks for comments. >>>>> >>>>> On 02/10/2015 03:54 PM, Alim Akhtar wrote: >>>>>> Hi Andrzej, >>>>>> >>>>>> On Tue, Feb 10, 2015 at 7:59 PM, Andrzej Hajda wrote: >>>>>>> According to specs for version 250A, status register should be >>>>>>> tested before clock update. Otherwise in case MMC card is missing >>>>>>> mci_send_cmd timeouts and subsequent CTYPE registry write causes system hang. >>>>>>> This behavior has been observed on Exynos5422/Odroid-XU3. >> I've also observed the same behavior (mmc command send timing out and >> system hang) on an Exynos5420 Peach Pit Chromebook and an Exynos5800 >> Peach Pi Chromebok which both have the same dw_mmc 250A IP version. >> >> Unfortunately $subject doesn't seem to be enough since even with that >> applied I got: >> >> [ 4.264418] mmc_host mmc1: Timeout sending command (cmd 0x202000 >> arg 0x0 status 0x80202000) >> [ 4.283988] random: nonblocking pool is initialized >> [ 28.054406] INFO: rcu_sched detected stalls on CPUs/tasks: >> [ 28.058412] 0: (5 ticks this GP) idle=65f/140000000000001/0 >> softirq=215/216 fqs=39 >> [ 28.066129] (detected by 1, t=4765 jiffies, g=-294, c=-295, q=2) >> [ 28.072202] Task dump for CPU 0: >> [ 28.075412] kworker/u16:0 R running 0 6 2 0x00000002 >> [ 28.081749] Workqueue: kmmcd mmc_rescan >> [ 28.085570] [] (__schedule) from [<00000000>] ( (null)) >> [ 28.091724] rcu_sched kthread starved for 796 jiffies! >> >>>>>>> +static bool dw_mci_wait_busy(struct dw_mci *host) >>>>>>> +{ >>>>>>> + unsigned long timeout; >>>>>>> + >>>>>>> + if (host->verid < DW_MMC_250A) >>>>>>> + return true; >>>>>>> + >>>>>> I wonder this might be true for 240A as well. >>>>> Odroid-U3 board with Exynos4412 and MMC 240A does not have this problem. >>>>> On the other side busy check does not hurt it anyway. >> This problem also does not happen on an Exynos5250 Snow Chromebook >> which has a dw_mmc IP version 241A. >> >>>> Which kernel version do you use? >>>> I also have the exynos5422 board, but i didn't find the below error yet. >>>> It doesn't relate with IP version. >>>> If you share your environment, i can check with exynos5422 board. >>> linux-next on odroid-xu3. With MMC card removed, booting from sdcard. >>> Please also note that broken-cd quirk is on in dts. > I can't find this problem on exynos5422 board.(Odroix-xu3) > Could you share the properties into dts file? It is just linux-next with exynos_defconfig and arch/arm/boot/dts/exynos5422-odroidxu3.dts, without changes: ... &mmc_0 { status = "okay"; mmc-pwrseq = <&emmc_pwrseq>; broken-cd; card-detect-delay = <200>; samsung,dw-mshc-ciu-div = <3>; samsung,dw-mshc-sdr-timing = <0 4>; samsung,dw-mshc-ddr-timing = <0 2>; pinctrl-names = "default"; pinctrl-0 = <&sd0_clk &sd0_cmd &sd0_bus4 &sd0_bus8>; bus-width = <8>; cap-mmc-highspeed; }; ... Regarding hardware: eMMC card removed, booting from sdcard. Regards Andrzej > > > Best Regards, > Jaehoon Chung > >> I tested by trying to add wifi support to the Peach Pit/Pi Chromebooks >> which have an SDIO wifi chip attached to mmc@12210000. This [0] is the >> patch I've on top of linux-next fwiw. >> >>>> I'm not sure but this patch could be dropped. >>>> Because this patch is just only checking whether card is busy or not. >>>> >>>> this patch(mmc:dw_mmc: fix bug that case 'timeout sending command') can cover your patch. >>> I will test it. >>> >> I tested it and although the mentioned patch does fix the mmc commands >> send timing out, now card detection seems to not be working since the >> kernel keeps waiting for aiting for root device /dev/mmcblk1p4... >> >> and the this error is shown: >> >> [ 4.249434] dwmmc_exynos 12210000.mmc: Data busy (status 0x306) >> >> So I tried the other patch from Addy's series "mmc: dw_mmc: Don't >> start command while data busy" but it did not have an effect. I still >> see the data busy error and the uSD card is not detected. >> >> Best regards, >> Javier >> >> [0]: http://paste.debian.net/plain/145877 >> >