From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: [patch 040/177] mmc: omap: fix for bus width which improves SD card's peformance. Date: Tue, 10 Aug 2010 18:01:46 -0700 Message-ID: <201008110101.o7B11kLv027065@imap1.linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:39751 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757897Ab0HKBC3 (ORCPT ); Tue, 10 Aug 2010 21:02:29 -0400 Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: torvalds@linux-foundation.org Cc: akpm@linux-foundation.org, kishore.kadiyala@ti.com, adrian.hunter@nokia.com, jhnikula@gmail.com, linux-mmc@vger.kernel.org, madhu.cr@ti.com, matt@console-pimps.org, nm@ti.com, svenkatr@ti.com, tony@atomide.com From: Kishore Kadiyala This patch improves low speeds for SD cards. OMAP-MMC controller's can support maximum bus width of '8'. when bus width is mentioned as "8" in controller data,the SD stack will check whether bus width is "4" and if not it will set bus width to "1" and there by degrading performance. This patch fixes the issue and improves the performance of SD cards. Signed-off-by: Kishore Kadiyala Signed-off-by: Venkatraman S Signed-off-by: Nishanth Menon Acked-by: Madhusudhan Chikkature Tested-by: Jarkko Nikula Cc: Adrian Hunter Cc: Matt Fleming Cc: Tony Lindgren Cc: Signed-off-by: Andrew Morton --- drivers/mmc/host/omap_hsmmc.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff -puN drivers/mmc/host/omap_hsmmc.c~mmc-omap-fix-for-bus-width-which-improves-sd-cards-peformance drivers/mmc/host/omap_hsmmc.c --- a/drivers/mmc/host/omap_hsmmc.c~mmc-omap-fix-for-bus-width-which-improves-sd-cards-peformance +++ a/drivers/mmc/host/omap_hsmmc.c @@ -2096,10 +2096,23 @@ static int __init omap_hsmmc_probe(struc mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED | MMC_CAP_WAIT_WHILE_BUSY; - if (mmc_slot(host).wires >= 8) + switch (mmc_slot(host).wires) { + case 8: mmc->caps |= MMC_CAP_8_BIT_DATA; - else if (mmc_slot(host).wires >= 4) + /* Fall through */ + case 4: mmc->caps |= MMC_CAP_4_BIT_DATA; + break; + case 1: + /* Nothing to crib here */ + case 0: + /* Assuming nothing was given by board, Core use's 1-Bit */ + break; + default: + /* Completely unexpected.. Core goes with 1-Bit Width */ + dev_crit(mmc_dev(host->mmc), "Invalid width %d\n used!" + "using 1 instead\n", mmc_slot(host).wires); + } if (mmc_slot(host).nonremovable) mmc->caps |= MMC_CAP_NONREMOVABLE; _