Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932159Ab0LBLcC (ORCPT ); Thu, 2 Dec 2010 06:32:02 -0500 Received: from wolverine02.qualcomm.com ([199.106.114.251]:11714 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757488Ab0LBLcA (ORCPT ); Thu, 2 Dec 2010 06:32:00 -0500 X-IronPort-AV: E=McAfee;i="5400,1158,6184"; a="64970696" Subject: Re: [PATCH v4] mmc: Make ID freq configurable From: Sahitya Tummala To: Hein_Tibosch Cc: Andrew Morton , Pierre Ossman , Chris Ball , Ben Nizette , Sascha Hauer , Adrian Hunter , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Matt Fleming In-Reply-To: <4C80187D.9000304@yahoo.es> References: <4C80187D.9000304@yahoo.es> Content-Type: text/plain Date: Thu, 02 Dec 2010 16:46:22 +0530 Message-Id: <1291288582.15187.91.camel@stummala-linux.in.qualcomm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3594 Lines: 115 Hi Hein Tibosch, On Fri, 2010-09-03 at 05:34 +0800, Hein_Tibosch wrote: > In the latest releases of the mmc driver, the freq during initialization > is set to a fixed 400 Khz. This was reportedly too fast for several > users. As there doesn't seem to be an ideal frequency which-works-for-all, > Pierre suggested to let the driver try several frequencies. > > This patch implements that idea. It will try mmc-initialization using > several frequencies from an array 400, 300, 200 and 100. > I submitted it earlier but it's now adapted to and tested with kernel > 2.6.36-rc3. > > In case SDIO is broken, it'll still try to detect SDMEM, also at different > freqs. > > Signed-off-by: Hein Tibosch > > --- > diff -Nurp a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > --- a/drivers/mmc/core/core.c 2010-08-29 23:36:04.000000000 +0800 > +++ b/drivers/mmc/core/core.c 2010-09-03 04:28:52.000000000 +0800 > @@ -907,12 +907,7 @@ static void mmc_power_up(struct mmc_host > */ > mmc_delay(10); > > - if (host->f_min > 400000) { > - pr_warning("%s: Minimum clock frequency too high for " > - "identification mode\n", mmc_hostname(host)); > - host->ios.clock = host->f_min; > - } else > - host->ios.clock = 400000; > + host->ios.clock = host->f_init; > > host->ios.power_mode = MMC_POWER_ON; > mmc_set_ios(host); > @@ -1404,6 +1399,8 @@ void mmc_rescan(struct work_struct *work > u32 ocr; > int err; > unsigned long flags; > + int i; > + unsigned freqs[] = { 400000, 300000, 200000, 100000 }; > > spin_lock_irqsave(&host->lock, flags); > > @@ -1443,55 +1440,64 @@ void mmc_rescan(struct work_struct *work > if (host->ops->get_cd && host->ops->get_cd(host) == 0) > goto out; > > - mmc_claim_host(host); > + for (i = 0; i < ARRAY_SIZE(freqs); i++) { > + mmc_claim_host(host); > > - mmc_power_up(host); > - sdio_reset(host); > - mmc_go_idle(host); > + if (freqs[i] >= host->f_min) > + host->f_init = freqs[i]; > + else if (i && freqs[i-1] <= host->f_min) > + goto out; > + else > + host->f_init = host->f_min; > > - mmc_send_if_cond(host, host->ocr_avail); > + printk ("mmc_rescan: trying %u Hz\n", host->f_init); > + mmc_power_up(host); > + sdio_reset(host); > + mmc_go_idle(host); > > - /* > - * First we search for SDIO... > - */ > - err = mmc_send_io_op_cond(host, 0, &ocr); > - if (!err) { > - if (mmc_attach_sdio(host, ocr)) { > - mmc_claim_host(host); > - /* try SDMEM (but not MMC) even if SDIO is broken */ > - if (mmc_send_app_op_cond(host, 0, &ocr)) > - goto out_fail; > + mmc_send_if_cond(host, host->ocr_avail); > + > + /* > + * First we search for SDIO... > + */ > + err = mmc_send_io_op_cond(host, 0, &ocr); > + if (!err) { > + if (mmc_attach_sdio(host, ocr)) { > + mmc_claim_host(host); > + /* try SDMEM (but not MMC) even if SDIO is broken */ > + if (mmc_send_app_op_cond(host, 0, &ocr)) In case of SDIO error, mmc_power_off() is getting called as part of mmc_detach_bus(). Shouldn't we power up the host before checking for SDMEM? Any comments? > + goto out_fail; > + > + if (mmc_attach_sd(host, ocr)) > + mmc_power_off(host); > + } > + goto out; > + } Thanks, Sahitya. -- Sent by a consultant of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- 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/