From: Ziyuan Xu Date: Thu, 26 May 2016 05:50:32 +0000 (+0800) Subject: mmc: mmc: Fix HS switch failure in mmc_select_hs400() X-Git-Tag: v4.8-rc1~81^2~119 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=649c6059d2371fef886a8f967e21416204723d63;p=platform%2Fkernel%2Flinux-exynos.git mmc: mmc: Fix HS switch failure in mmc_select_hs400() To slove the issue which was found on gru board for hs400. [ 4.616946] sdhci: Secure Digital Host Controller Interface driver [ 4.623135] sdhci: Copyright(c) Pierre Ossman [ 4.722575] sdhci-pltfm: SDHCI platform and OF driver helper [ 4.730962] sdhci-arasan fe330000.sdhci: No vmmc regulator found [ 4.737444] sdhci-arasan fe330000.sdhci: No vqmmc regulator found [ 4.774930] mmc0: SDHCI controller on fe330000.sdhci [fe330000.sdhci] using ADMA [ 4.980295] mmc0: switch to high-speed from hs200 failed, err:-84 [ 4.986487] mmc0: error -84 whilst initialising MMC card We should change HS400 mode selection timing to meet JEDEC specification. The JEDEC 5.1 said that change the frequency to <= 52MHZ after HS_TIMING switch. Refer to section 6.6.2.3 "HS400" timing mode selection: Set the "Timing Interface" parameter in the HS_TIMING[185] field of the Extended CSD register to 0x1 to switch to High Speed mode and then set the clock frequency to a value not greater than 52MHZ. Signed-off-by: Ziyuan Xu Signed-off-by: Ulf Hansson --- diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 490229e..900b9f9 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1082,10 +1082,6 @@ static int mmc_select_hs400(struct mmc_card *card) host->ios.bus_width == MMC_BUS_WIDTH_8)) return 0; - /* Reduce frequency to HS frequency */ - max_dtr = card->ext_csd.hs_max_dtr; - mmc_set_clock(host, max_dtr); - /* Switch card to HS mode */ val = EXT_CSD_TIMING_HS; err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, @@ -1101,6 +1097,10 @@ static int mmc_select_hs400(struct mmc_card *card) /* Set host controller to HS timing */ mmc_set_timing(card->host, MMC_TIMING_MMC_HS); + /* Reduce frequency to HS frequency */ + max_dtr = card->ext_csd.hs_max_dtr; + mmc_set_clock(host, max_dtr); + err = mmc_switch_status(card); if (err) goto out_err;