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| H A D | dw_mmc.c | diff 9d9491a7da2a4ce9fed32bd8611992ea3471523a Thu Oct 12 22:11:17 CEST 2017 Douglas Anderson <dianders@chromium.org> mmc: dw_mmc: Fix the DTO timeout calculation
Just like the CTO timeout calculation introduced recently, the DTO
timeout calculation was incorrect. It used "bus_hz" but, as far as I
can tell, it's supposed to use the card clock. Let's account for the
div value, which is documented as 2x the value stored in the register,
or 1 if the register is 0.
NOTE: This was likely not terribly important until commit 16a34574c6ca
("mmc: dw_mmc: remove the quirks flags") landed because "DIV" is
documented on Rockchip SoCs (the ones that used to define the quirk)
to always be 0 or 1. ...and, in fact, it's documented to only be 1
with EMMC in 8-bit DDR52 mode. Thus before the quirk was applied to
everyone it was mostly OK to ignore the DIV value.
I haven't personally observed any problems that are fixed by this
patch but I also haven't tested this anywhere with a DIV other an 0.
AKA: this problem was found simply by code inspection and I have no
failing test cases that are fixed by it. Presumably this could fix
real bugs for someone out there, though.
Fixes: 16a34574c6ca ("mmc: dw_mmc: remove the quirks flags")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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