Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754899Ab2ENIfo (ORCPT ); Mon, 14 May 2012 04:35:44 -0400 Received: from na3sys009aog116.obsmtp.com ([74.125.149.240]:60572 "HELO na3sys009aog116.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751499Ab2ENIfm (ORCPT ); Mon, 14 May 2012 04:35:42 -0400 From: yongd To: cjb@laptop.org, linux-mmc@vger.kernel.org Cc: prakity@marvell.com, ohad@wizery.com, linus.walleij@linaro.org, ulf.hansson@stericsson.com, linux-kernel@vger.kernel.org, yongd Subject: [PATCH] mmc:sdio:guarantee setting card data bus width as 4-bit Date: Mon, 14 May 2012 16:35:10 +0800 Message-Id: <1336984510-9723-1-git-send-email-yongd@marvell.com> X-Mailer: git-send-email 1.7.9.5 X-OriginalArrivalTime: 14 May 2012 08:35:11.0080 (UTC) FILETIME=[79C67E80:01CD31AC] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1980 Lines: 57 SDIO_CCCR_IF[1:0] in SDIO card is used for card data bus width setting as below, 00b: 1-bit bus 01b: Reserved 10b: 4-bit bus 11b: 8-bit bus(only for embedded SDIO) And sdio_enable_wide is for setting data bus width as 4-bit. But currently, it 1stly read the register, 2ndly OR' 1b with SDIO_CCCR_IF[1], and then write it back. As we can see, such way is based on such assumption that the SDIO_CCCR_IF[0] is always 0. Apparently, this is not right. Signed-off-by: yongd --- drivers/mmc/core/sdio.c | 6 ++++++ include/linux/mmc/sdio.h | 2 ++ 2 files changed, 8 insertions(+) diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c index 13d0e95..6b6f902 100644 --- a/drivers/mmc/core/sdio.c +++ b/drivers/mmc/core/sdio.c @@ -218,6 +218,12 @@ static int sdio_enable_wide(struct mmc_card *card) if (ret) return ret; + if ((ctrl & SDIO_BUS_WIDTH_MASK) + == SDIO_BUS_WIDTH_RESERVED) + printk(KERN_WARNING"SDIO_CCCR_IF is invalid: %d\n", ctrl); + + /* set as 4-bit bus width */ + ctrl &= ~SDIO_BUS_WIDTH_MASK; ctrl |= SDIO_BUS_WIDTH_4BIT; ret = mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_IF, ctrl, NULL); diff --git a/include/linux/mmc/sdio.h b/include/linux/mmc/sdio.h index c9fe66c..17446d3 100644 --- a/include/linux/mmc/sdio.h +++ b/include/linux/mmc/sdio.h @@ -98,7 +98,9 @@ #define SDIO_CCCR_IF 0x07 /* bus interface controls */ +#define SDIO_BUS_WIDTH_MASK 0x03 /* data bus width setting */ #define SDIO_BUS_WIDTH_1BIT 0x00 +#define SDIO_BUS_WIDTH_RESERVED 0x01 #define SDIO_BUS_WIDTH_4BIT 0x02 #define SDIO_BUS_ECSI 0x20 /* Enable continuous SPI interrupt */ #define SDIO_BUS_SCSI 0x40 /* Support continuous SPI interrupt */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/