From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753702AbaIOL31 (ORCPT ); Mon, 15 Sep 2014 07:29:27 -0400 Received: from mail-oi0-f50.google.com ([209.85.218.50]:63822 "EHLO mail-oi0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752451AbaIOL3Z (ORCPT ); Mon, 15 Sep 2014 07:29:25 -0400 MIME-Version: 1.0 In-Reply-To: References: <1410265614-3275-1-git-send-email-jean-michel.hautbois@vodalys.com> <54110B29.7030303@samsung.com> <5416C30C.6010400@samsung.com> From: Jean-Michel Hautbois Date: Mon, 15 Sep 2014 13:29:10 +0200 X-Google-Sender-Auth: PoXemY9lBpEn1jMjU8-I2MpwIhs Message-ID: Subject: Re: [PATCH] mmc: Add delay between CMD6 and CMD13 for Sandisk eMMC cards To: Jaehoon Chung Cc: linux-kernel , "linux-mmc@vger.kernel.org" , "tgih.jun@samsung.com" , Ulf Hansson , Chris Ball Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2014-09-15 12:53 GMT+02:00 Jean-Michel Hautbois : > 2014-09-15 12:44 GMT+02:00 Jaehoon Chung : >> On 09/15/2014 07:08 PM, Jean-Michel Hautbois wrote: >>> Hi Jaehoon, >>> >>>> On 09/09/2014 09:26 PM, Jean-Michel Hautbois wrote: >>>>> Tested on a i.MX6 board, with Sandisk SDIN5D1-2G. >>>>> Without this patch, I/O errors occur. >>>>> This eMMC seems to have a different Manufacturer ID as it reads 0x45 >>>>> and not 0x2 as specified in datasheet. >>>> >>>> I think this patch don't merge into mainline. >>>> This is not solution for problem. >>>> you mentioned the below comment, this is workaround. >>> >>> Yes >>> >>>>> >>>>> Signed-off-by: Jean-Michel Hautbois >>>>> --- >>>>> drivers/mmc/core/mmc_ops.c | 9 +++++++++ >>>>> 1 file changed, 9 insertions(+) >>>>> >>>>> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c >>>>> index f51b5ba..91babaa 100644 >>>>> --- a/drivers/mmc/core/mmc_ops.c >>>>> +++ b/drivers/mmc/core/mmc_ops.c >>>>> @@ -458,6 +458,15 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value, >>>>> if (!use_busy_signal) >>>>> return 0; >>>>> >>>>> + /* WORKAROUND: for Sandisk eMMC cards, it might need certain delay >>>>> + * before sending CMD13 after CMD6 >>>>> + * On SDIN5D1-2G MANFID is 0x45 and not 0x2 as specified in datasheet >>>>> + */ >>>>> + if (card->cid.manfid == CID_MANFID_SANDISK || >>>>> + card->cid.manfid == 0x45) { >>>>> + msleep(1); >>>>> + } >>>> >>>> If it's a general problem of Sandisk SDIN5D1-2G, >>>> I think you need to verify this problem. And can you use the MMC_FIXUP() and QUIRK? >>> >>> Well, this is difficult to verify, I know that on all my SDIN5D1-2G I >>> have this MANFID different from what is defined by CID_MANFID_SANDISK. >>> How should I use MMC_FIXUP ? Like this ? >> >> I think you need to explain why delay is need. >> i didn't have same card, but it might be your host controller or other problem. > > Well, I don't know why it is needed, this is undocumented, nothing in > datasheet explains anything about this. It seems to be uSDHC / DDR mode related. I don't even know if this is limited to Sandisk ! And I don't have another board with another manufacturer eMMC to test. Maybe some guys from Freescale could help with this ? Thanks, JM