From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: use default speed of the eMMC Date: Thu, 26 May 2016 14:49:17 +0900 Message-ID: <57468E5D.8040606@samsung.com> References: <574421CE.4080503@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mailout3.samsung.com ([203.254.224.33]:34819 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750794AbcEZFtV convert rfc822-to-8bit (ORCPT ); Thu, 26 May 2016 01:49:21 -0400 Received: from epcpsbgr5.samsung.com (u145.gpu120.samsung.co.kr [203.254.230.145]) by mailout3.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0O7R02OU1S65XO60@mailout3.samsung.com> for linux-mmc@vger.kernel.org; Thu, 26 May 2016 14:49:17 +0900 (KST) In-reply-to: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: =?UTF-8?B?7J6l66+87Jqw?= Cc: linux-mmc@vger.kernel.org On 05/26/2016 02:16 PM, =EC=9E=A5=EB=AF=BC=EC=9A=B0 wrote: > Hello, Jaehoon Chung. >=20 > I mentioned "default speed mode" not hs200, hs400, ddr and hs mode. Yes, default speed mode is not HS400, HS400, DDR.. You mean "default speed mode" is 26MHz? As i know, default speed is 26MHz. and it used for initializing card. >=20 > I think If "default speed mode" is set, there is no bus width change. There is DEVICE_TYPE[196] at ext_csd register. Device type should be selected one of them. (You can see the currently = valid value.) I don't know exactly what your purpose. If i missed something, let me know in more detail about default speed, = eMMC version, your environment. Best Regards, Jaehoon Chung >=20 > If you have any advice to use "default speed mode" of the eMMC. pleas= e > let me know. >=20 > Thank you. >=20 > Best Regards, > Minwoo Jang. >=20 > 2016-05-24 18:41 GMT+09:00 Jaehoon Chung : >> Hi, >> >> On 05/24/2016 06:07 PM, =EC=9E=A5=EB=AF=BC=EC=9A=B0 wrote: >>> Dear linux-mmc. >>> >>> Hello, I'm Minwoo Jang. >>> >>> I have a question about using default speed of the eMMC. >>> >>> When default speed is used, mmc_select_bus_width() is never called. >>> >>> So, eMMC can not be set 4 bit or 8 bit bus width, I think. >>> >>> Please, give me your opinions on the following diff codes. >> >> In mmc_select_timing(), timing should be set to MMC_TIMING_HS or oth= ers. >> Then mmc_select_bus_width() should be entered. >> >> Best Regards, >> Jaehoon Chung >> >>> >>> Thank you. >>> >>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D >>> >>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c >>> index 94b4462..3b1cc4d 100644 >>> --- a/drivers/mmc/core/mmc.c >>> +++ b/drivers/mmc/core/mmc.c >>> @@ -952,6 +952,8 @@ static int mmc_select_bus_width(struct mmc_card= *card) >>> >>> if (!err) { >>> err =3D bus_width; >>> + pr_warn("%s: switch to bus width %d\n", >>> + mmc_hostname(host), (1 << bus_width= )); >>> break; >>> } else { >>> pr_warn("%s: switch to bus width %d failed\= n", >>> @@ -1500,6 +1502,14 @@ static int mmc_init_card(struct mmc_host *ho= st, u32 ocr, >>> if (err) >>> goto err; >>> } >>> + } else { >>> + /* Select the bus width for normal speed mode */ >>> + err =3D mmc_select_bus_width(card); >>> + if (IS_ERR_VALUE(err)) { >>> + pr_warn("%s: Selecting bus width failed\n", >>> + mmc_hostname(card->host)); >>> + goto err; >>> + } >>> } >>> >>> Best regards, >>> >>> MW Jang. >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-mmc= " in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >>> >>> >> >=20 >=20 >=20