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authorAl Cooper <alcooperx@gmail.com>2012-11-30 10:53:35 -0500
committerChris Ball <cjb@laptop.org>2012-12-06 13:55:11 -0500
commitccb52a00fd3fdea428e29816cbacb0a78090d474 (patch)
tree280a46cf6b880f5ba7cb3f172c328052d7fe4427 /drivers/mmc
parent780f22af85991be4f7c51c512726eee931707fff (diff)
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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 <alcooperx@gmail.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/core/mmc.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index f605d6e3d2c..e6e39111e05 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;
}