From ccb52a00fd3fdea428e29816cbacb0a78090d474 Mon Sep 17 00:00:00 2001 From: Al Cooper Date: Fri, 30 Nov 2012 10:53:35 -0500 Subject: [PATCH] mmc: Limit MMC speed to 52MHz if not HS200 If "caps2" host capabilities does not indicate support for MMC HS200, don't allow clock speeds >52MHz. Currently, for MMC, the clock speed is set to the lesser of the max speed the eMMC module supports (card->ext_csd.hs_max_dtr) or the max base clock of the host controller (host->f_max based on BASE_CLK_FREQ in the host CAPS register). This means that a host controller that doesn't support HS200 mode but has a base clock of 100MHz and an eMMC module that supports HS200 speeds will end up using a 100MHz clock. Signed-off-by: Al Cooper Signed-off-by: Chris Ball --- drivers/mmc/core/mmc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index f605d6e3d2cd..e6e39111e05b 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1066,6 +1066,8 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, if (mmc_card_highspeed(card) || mmc_card_hs200(card)) { if (max_dtr > card->ext_csd.hs_max_dtr) max_dtr = card->ext_csd.hs_max_dtr; + if (mmc_card_highspeed(card) && (max_dtr > 52000000)) + max_dtr = 52000000; } else if (max_dtr > card->csd.max_dtr) { max_dtr = card->csd.max_dtr; }