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authorDouglas Anderson2017-10-12 13:11:17 -0700
committerUlf Hansson2017-11-01 15:13:45 +0100
commit9d9491a7da2a4ce9fed32bd8611992ea3471523a (patch)
treebb7a26b38e54f61396eba6f3bfcf449f0f2f5033 /drivers/mmc
parent8892b705f58e105b0b4ce3402afa1d1b803fb207 (diff)
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>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/host/dw_mmc.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 50148991f30e..4f2806720c5c 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1936,10 +1936,15 @@ static int dw_mci_data_complete(struct dw_mci *host, struct mmc_data *data)
static void dw_mci_set_drto(struct dw_mci *host)
{
unsigned int drto_clks;
+ unsigned int drto_div;
unsigned int drto_ms;
drto_clks = mci_readl(host, TMOUT) >> 8;
- drto_ms = DIV_ROUND_UP(drto_clks, host->bus_hz / 1000);
+ drto_div = (mci_readl(host, CLKDIV) & 0xff) * 2;
+ if (drto_div == 0)
+ drto_div = 1;
+ drto_ms = DIV_ROUND_UP(MSEC_PER_SEC * drto_clks * drto_div,
+ host->bus_hz);
/* add a bit spare time */
drto_ms += 10;