From 9d9491a7da2a4ce9fed32bd8611992ea3471523a Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Thu, 12 Oct 2017 13:11:17 -0700 Subject: 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 Reviewed-by: Shawn Lin Signed-off-by: Ulf Hansson --- drivers/mmc/host/dw_mmc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/mmc/host/dw_mmc.c') 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; -- cgit v1.2.3