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mmc: core: changes frequency to hs_max_dtr when selecting hs400es

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Per JESD84-B51 P49, Host need to change frequency to <=52MHz
after setting HS_TIMING to 0x1, and host may changes frequency
to <= 200MHz after setting HS_TIMING to 0x3. That means the card
expects the clock rate to increase from the current used f_init
(which is less than 400KHz, but still being less than 52MHz) to
52MHz, otherwise we find some eMMC devices significantly report
failure when sending status.

Reported-by: Xiao Yao <xiaoyao@rock-chips.com>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Shawn Lin 2016-09-30 14:18:59 +08:00 committed by Ulf Hansson
parent 1720d3545b
commit 4f25580fb8
1 changed files with 2 additions and 0 deletions
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2
drivers/mmc/core/mmc.c
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@ -1282,6 +1282,8 @@ static int mmc_select_hs400es(struct mmc_card *card)
if (err)
goto out_err;
mmc_set_clock(host, card->ext_csd.hs_max_dtr);
err = mmc_switch_status(card);
if (err)
goto out_err;