Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754957Ab2FFNXm (ORCPT ); Wed, 6 Jun 2012 09:23:42 -0400 Received: from void.printf.net ([89.145.121.20]:45614 "EHLO void.printf.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754227Ab2FFNXk (ORCPT ); Wed, 6 Jun 2012 09:23:40 -0400 From: Chris Ball To: yongd Cc: linux-mmc@vger.kernel.org, prakity@marvell.com, ohad@wizery.com, linus.walleij@linaro.org, ulf.hansson@stericsson.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mmc:sdio:guarantee setting card data bus width as 4-bit References: <1337058583-2014-1-git-send-email-yongd@marvell.com> Date: Wed, 06 Jun 2012 09:23:32 -0400 In-Reply-To: <1337058583-2014-1-git-send-email-yongd@marvell.com> (yongd@marvell.com's message of "Tue, 15 May 2012 13:09:43 +0800") Message-ID: <87r4ts4lrf.fsf@octavius.laptop.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.95 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2270 Lines: 65 Hi, On Tue, May 15 2012, yongd wrote: > 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 | 7 +++++++ > include/linux/mmc/sdio.h | 2 ++ > 2 files changed, 9 insertions(+) > > diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c > index 13d0e95..7b528cf 100644 > --- a/drivers/mmc/core/sdio.c > +++ b/drivers/mmc/core/sdio.c > @@ -218,6 +218,13 @@ 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"%s: SDIO_CCCR_IF is invalid: 0x%02X\n", > + mmc_hostname(card->host), 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 */ Thanks, pushed to mmc-next for 3.5. - Chris. -- Chris Ball One Laptop Per Child -- 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/