From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Ball Subject: Re: [PATCH] mmc: core: add comment why sdio_reset is done at init time Date: Thu, 24 Feb 2011 18:41:21 +0000 Message-ID: <20110224184121.GA11663@void.printf.net> References: <1091D46E-68D9-49FC-BBA6-6908BC1835AD@marvell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from void.printf.net ([89.145.121.20]:47656 "EHLO void.printf.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752859Ab1BXSlW (ORCPT ); Thu, 24 Feb 2011 13:41:22 -0500 Content-Disposition: inline In-Reply-To: <1091D46E-68D9-49FC-BBA6-6908BC1835AD@marvell.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Philip Rakity Cc: "linux-mmc@vger.kernel.org" , Mark Brown Hi Philip, On Sun, Feb 13, 2011 at 11:12:28PM -0800, Philip Rakity wrote: > > sdio_reset sends a CMD52 to reset the sdio card. This is > highly recommended for sdio cards being reinitialized. Since > we do not know if the card is being reinitialized we just send > the command. SD/eMMC cards are supposed to ignore the CMD > before the CMD0. Document why we are doing this. > > Signed-off-by: Philip Rakity > --- > drivers/mmc/core/core.c | 6 ++++++ > 1 files changed, 6 insertions(+), 0 deletions(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > index 34a7e8c..d9fb0d3 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -1494,6 +1494,12 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq) > mmc_hostname(host), __func__, host->f_init); > #endif > mmc_power_up(host); > + > + /* > + * sdio_reset sends CMD52 to reset card. Since we do not know > + * if the card is being re-initialzed just send it. CMD52 > + * should be ignored by SD/eMMC cards > + */ > sdio_reset(host); > mmc_go_idle(host); > Thanks, pushed to mmc-next for .39. -- Chris Ball One Laptop Per Child