From patchwork Wed Oct 28 12:25:43 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adrian Hunter X-Patchwork-Id: 7509971 Return-Path: X-Original-To: patchwork-linux-mmc@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 9F15EBEEA4 for ; Wed, 28 Oct 2015 12:29:19 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A956E207AF for ; Wed, 28 Oct 2015 12:29:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D52C020830 for ; Wed, 28 Oct 2015 12:29:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932187AbbJ1M3O (ORCPT ); Wed, 28 Oct 2015 08:29:14 -0400 Received: from mga01.intel.com ([192.55.52.88]:8119 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932454AbbJ1M3N (ORCPT ); Wed, 28 Oct 2015 08:29:13 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP; 28 Oct 2015 05:28:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,209,1444719600"; d="scan'208";a="821399087" Received: from ahunter-desktop.fi.intel.com ([10.237.72.168]) by fmsmga001.fm.intel.com with ESMTP; 28 Oct 2015 05:28:51 -0700 From: Adrian Hunter To: Ulf Hansson Cc: linux-mmc , Seungwon Jeon , Jaehoon Chung , Chaotian Jing Subject: [PATCH 4/4] mmc: mmc: Improve reliability of mmc_select_hs400() Date: Wed, 28 Oct 2015 14:25:43 +0200 Message-Id: <1446035143-4949-5-git-send-email-adrian.hunter@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1446035143-4949-1-git-send-email-adrian.hunter@intel.com> References: <1446035143-4949-1-git-send-email-adrian.hunter@intel.com> Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP mmc_select_hs400() calls __mmc_switch() which checks the switch is successful using CMD13 (SEND_STATUS). The problem is that it does that using the timing settings of the previous mode. That is prone to error, especially when switching from HS to HS400 because the timing parameters for HS mode are tighter than the timing parameters for HS400 mode. In the case when CMD13 polling is used (i.e. not MMC_CAP_WAIT_WHILE_BUSY) with the switch command, it must be assumed that using different modes on the card and host must work. However in the case when CMD13 polling is not used (i.e. MMC_CAP_WAIT_WHILE_BUSY) mmc_select_hs400() can be made more reliable by setting the host to the correct timing before sending CMD13. This patch does that. Signed-off-by: Adrian Hunter --- drivers/mmc/core/mmc.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 5884c79346da..3a9a79ec4343 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1056,6 +1056,7 @@ static int mmc_switch_status(struct mmc_card *card) static int mmc_select_hs400(struct mmc_card *card) { struct mmc_host *host = card->host; + bool send_status = true; unsigned int max_dtr; int err = 0; u8 val; @@ -1067,6 +1068,9 @@ static int mmc_select_hs400(struct mmc_card *card) host->ios.bus_width == MMC_BUS_WIDTH_8)) return 0; + if (host->caps & MMC_CAP_WAIT_WHILE_BUSY) + send_status = false; + /* Reduce frequency to HS frequency */ max_dtr = card->ext_csd.hs_max_dtr; mmc_set_clock(host, max_dtr); @@ -1077,7 +1081,7 @@ static int mmc_select_hs400(struct mmc_card *card) err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING, val, card->ext_csd.generic_cmd6_time, - true, true, true); + true, send_status, true); if (err) { pr_err("%s: switch to high-speed from hs200 failed, err:%d\n", mmc_hostname(host), err); @@ -1087,6 +1091,13 @@ static int mmc_select_hs400(struct mmc_card *card) /* Set host controller to HS timing */ mmc_set_timing(card->host, MMC_TIMING_MMC_HS); + if (!send_status) { + err = mmc_switch_status(card); + if (err) + goto out_err; + } + + /* Switch card to DDR */ err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BUS_WIDTH, EXT_CSD_DDR_BUS_WIDTH_8, @@ -1097,22 +1108,35 @@ static int mmc_select_hs400(struct mmc_card *card) return err; } + /* Switch card to HS400 */ val = EXT_CSD_TIMING_HS400 | card->drive_strength << EXT_CSD_DRV_STR_SHIFT; err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING, val, card->ext_csd.generic_cmd6_time, - true, true, true); + true, send_status, true); if (err) { pr_err("%s: switch to hs400 failed, err:%d\n", mmc_hostname(host), err); return err; } + /* Set host controller to HS400 timing and frequency */ mmc_set_timing(host, MMC_TIMING_MMC_HS400); mmc_set_bus_speed(card); + if (!send_status) { + err = mmc_switch_status(card); + if (err) + goto out_err; + } + return 0; + +out_err: + pr_err("%s: %s failed, error %d\n", mmc_hostname(card->host), + __func__, err); + return err; } int mmc_hs200_to_hs400(struct mmc_card *card)