From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755713AbdJLULo (ORCPT ); Thu, 12 Oct 2017 16:11:44 -0400 Received: from mail-pf0-f178.google.com ([209.85.192.178]:48752 "EHLO mail-pf0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755299AbdJLULl (ORCPT ); Thu, 12 Oct 2017 16:11:41 -0400 X-Google-Smtp-Source: AOwi7QDoqLfYuf0uLXTcB5b9DrtvXYUel2BuExuHqPlwh0RiKn7ewZR07y0mjKknr0nLDLY+8YQQkQ== From: Douglas Anderson To: jh80.chung@samsung.com, ulf.hansson@linaro.org, shawn.lin@rock-chips.com Cc: xzy.xu@rock-chips.com, amstan@chromium.org, linux-rockchip@lists.infradead.org, briannorris@chromium.org, linux-samsung-soc@vger.kernel.org, kernel@esmil.dk, Douglas Anderson , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/5] mmc: dw_mmc: Fix the CTO timeout calculation Date: Thu, 12 Oct 2017 13:11:15 -0700 Message-Id: <20171012201118.23570-3-dianders@chromium.org> X-Mailer: git-send-email 2.15.0.rc0.271.g36b669edcc-goog In-Reply-To: <20171012201118.23570-1-dianders@chromium.org> References: <20171012201118.23570-1-dianders@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the commit 03de19212ea3 ("mmc: dw_mmc: introduce timer for broken command transfer over scheme") we tried to calculate the expected hardware command timeout value. Unfortunately that calculation isn't quite correct in all cases. 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: It's not expected that this will actually fix anything important since the 10 ms margin added by the function will pretty much dwarf any calculations. The card clock should be 100 kHz at minimum and: 1000 ms/s * (255 * 2) / 100000 Hz. Gives us 5.1 ms. ...so really the point of this patch is just to make the code more "correct" in case anyone ever tries to remove the 10 ms buffer. Fixes: 03de19212ea3 ("mmc: dw_mmc: introduce timer for broken command transfer over scheme") Tested-by: Emil Renner Berthing Reviewed-by: Shawn Lin Signed-off-by: Douglas Anderson --- Changes in v2: None drivers/mmc/host/dw_mmc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index f5b2bb4b4d98..16516c528a88 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -401,10 +401,14 @@ static u32 dw_mci_prep_stop_abort(struct dw_mci *host, struct mmc_command *cmd) static inline void dw_mci_set_cto(struct dw_mci *host) { unsigned int cto_clks; + unsigned int cto_div; unsigned int cto_ms; cto_clks = mci_readl(host, TMOUT) & 0xff; - cto_ms = DIV_ROUND_UP(cto_clks, host->bus_hz / 1000); + cto_div = (mci_readl(host, CLKDIV) & 0xff) * 2; + if (cto_div == 0) + cto_div = 1; + cto_ms = DIV_ROUND_UP(MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); /* add a bit spare time */ cto_ms += 10; -- 2.15.0.rc0.271.g36b669edcc-goog