From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: [PATCH V3 2/2] mmc: core: fix performance regression initializing MMC host controllers Date: Fri, 05 Apr 2013 16:31:12 +0300 Message-ID: <515ED220.5050105@intel.com> References: <1365082866-28404-1-git-send-email-adrian.hunter@intel.com> <1365082866-28404-3-git-send-email-adrian.hunter@intel.com> <515E7CB2.9020602@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com ([134.134.136.24]:6036 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161486Ab3DENZv (ORCPT ); Fri, 5 Apr 2013 09:25:51 -0400 In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Chris Ball Cc: Ulf Hansson , linux-mmc@vger.kernel.org, Linus Walleij , Namjae Jeon , Sergey Yanovich , Jaehoon Chung , Mark Brown Commit fa5501890d8974301042e0202d342a6cbe8609f4 introduced a boot time performance regression by adding mmc_power_up() to mmc_start_host(). mmc_power_up() is not necessary to host controller initialization, it is part of card initialization and is performed anyway asynchronously. Please see the original commit for an explanation of the use of mmc_power_up() in mmc_start_host(). This patch allows a driver to leave the power up in asynchronous code (as it was before). On my current target platform this reduces driver initialization from: [ 1.313220] initcall sdhci_acpi_driver_init+0x0/0x12 returned 0 after 102008 usecs to this: [ 1.217209] initcall sdhci_acpi_driver_init+0x0/0x12 returned 0 after 8331 usecs Signed-off-by: Adrian Hunter --- drivers/mmc/core/core.c | 3 ++- drivers/mmc/host/sdhci-acpi.c | 2 ++ include/linux/mmc/host.h | 1 + 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 3bf1c46..c1893c9 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2416,7 +2416,8 @@ void mmc_start_host(struct mmc_host *host) { host->f_init = max(freqs[0], host->f_min); host->rescan_disable = 0; - mmc_power_up(host); + if (!(host->caps2 & MMC_CAP2_NO_PRESCAN_POWERUP)) + mmc_power_up(host); mmc_detect_change(host, 0); } diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c index 2592ddd..7bcf74b 100644 --- a/drivers/mmc/host/sdhci-acpi.c +++ b/drivers/mmc/host/sdhci-acpi.c @@ -195,6 +195,8 @@ static int sdhci_acpi_probe(struct platform_device *pdev) host->mmc->pm_caps |= c->slot->pm_caps; } + host->mmc->caps2 |= MMC_CAP2_NO_PRESCAN_POWERUP; + err = sdhci_add_host(host); if (err) goto err_free; diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 17d7148..8873e83 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -280,6 +280,7 @@ struct mmc_host { #define MMC_CAP2_PACKED_WR (1 << 13) /* Allow packed write */ #define MMC_CAP2_PACKED_CMD (MMC_CAP2_PACKED_RD | \ MMC_CAP2_PACKED_WR) +#define MMC_CAP2_NO_PRESCAN_POWERUP (1 << 14) /* Don't power up before scan */ mmc_pm_flag_t pm_caps; /* supported pm features */ -- 1.7.11.7