From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752547AbbBKDH3 (ORCPT ); Tue, 10 Feb 2015 22:07:29 -0500 Received: from regular1.263xmail.com ([211.150.99.134]:54674 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751256AbbBKDH0 (ORCPT ); Tue, 10 Feb 2015 22:07:26 -0500 X-263anti-spam: KSV:0; X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 X-RL-SENDER: addy.ke@rock-chips.com X-FST-TO: jh80.chung@samsung.com X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: addy.ke@rock-chips.com X-UNIQUE-TAG: X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Message-ID: <54DAC762.2050404@rock-chips.com> Date: Wed, 11 Feb 2015 11:07:14 +0800 From: Addy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Jaehoon Chung , robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, rdunlap@infradead.org, tgih.jun@samsung.com, chris@printf.net, ulf.hansson@linaro.org, dinguyen@altera.com, heiko@sntech.de, olof@lixom.net, dianders@chromium.org, sonnyrao@chromium.org, amstan@chromium.org, djkurtz@chromium.org CC: devicetree@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, zhenfu.fang@rock-chips.com, cf@rock-chips.com, lintao@rock-chips.com, chenfen@rock-chips.com, zyf@rock-chips.com, xjq@rock-chips.com, huangtao@rock-chips.com, zyw@rock-chips.com, yzq@rock-chips.com, hj@rock-chips.com, kever.yang@rock-chips.com, zhangqing@rock-chips.com, hl@rock-chips.com Subject: Re: [PATCH v2 1/2] mmc: dw_mmc: fix bug that cause 'Timeout sending command' References: <1423134801-23219-1-git-send-email-addy.ke@rock-chips.com> <1423466726-20833-1-git-send-email-addy.ke@rock-chips.com> <1423466726-20833-2-git-send-email-addy.ke@rock-chips.com> <54D88560.4050808@samsung.com> In-Reply-To: <54D88560.4050808@samsung.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/02/09 18:01, Jaehoon Chung wrote: > Hi, Addy. > > On 02/09/2015 04:25 PM, Addy Ke wrote: >> Because of some uncertain factors, such as worse card or worse hardware, >> DAT[3:0](the data lines) may be pulled down by card, and mmc controller >> will be in busy state. This should not happend when mmc controller >> send command to update card clocks. If this happends, mci_send_cmd will >> be failed and we will get 'Timeout sending command', and then system will >> be blocked. To avoid this, we need reset mmc controller. >> >> Signed-off-by: Addy Ke >> --- >> drivers/mmc/host/dw_mmc.c | 28 ++++++++++++++++++++++++++++ >> 1 file changed, 28 insertions(+) >> >> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c >> index 4d2e3c2..b0b57e3 100644 >> --- a/drivers/mmc/host/dw_mmc.c >> +++ b/drivers/mmc/host/dw_mmc.c >> @@ -100,6 +100,7 @@ struct idmac_desc { >> }; >> #endif /* CONFIG_MMC_DW_IDMAC */ >> >> +static int dw_mci_card_busy(struct mmc_host *mmc); >> static bool dw_mci_reset(struct dw_mci *host); >> static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset); >> >> @@ -888,6 +889,31 @@ static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg) >> cmd, arg, cmd_status); >> } >> >> +static void dw_mci_wait_busy(struct dw_mci_slot *slot) >> +{ >> + struct dw_mci *host = slot->host; >> + unsigned long timeout = jiffies + msecs_to_jiffies(500); >> + >> + do { >> + if (!dw_mci_card_busy(slot->mmc)) >> + return; >> + cpu_relax(); >> + } while (time_before(jiffies, timeout)); >> + >> + dev_err(host->dev, "Data busy (status %#x)\n", >> + mci_readl(slot->host, STATUS)); >> + >> + /* >> + * Data busy, this should not happend when mmc controller send command >> + * to update card clocks in non-volt-switch state. If it happends, we >> + * should reset controller to avoid getting "Timeout sending command". >> + */ >> + dw_mci_ctrl_reset(host, SDMMC_CTRL_ALL_RESET_FLAGS); > If reset is failed, then dw_mci_ctrl_reset should return "false". > > ret = dw_mci_ctrl_reset(); > > WARN_ON(!ret || dw_mci_card_busy(slot->mmc)); > > Is it right? you are right, and I will update it in my next version patch. thank you. > > In my experiment, if reset is failed or card is busy, eMMC can't work anymore..right? > I think this patch is reasonable to prevent blocking issue. > > Best Regards, > Jaehoon Chung > > >> + >> + /* Fail to reset controller or still data busy, WARN_ON! */ >> + WARN_ON(dw_mci_card_busy(slot->mmc)); >> +} >> + >> static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) >> { >> struct dw_mci *host = slot->host; >> @@ -899,6 +925,8 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) >> /* We must continue to set bit 28 in CMD until the change is complete */ >> if (host->state == STATE_WAITING_CMD11_DONE) >> sdmmc_cmd_bits |= SDMMC_CMD_VOLT_SWITCH; >> + else >> + dw_mci_wait_busy(slot); >> >> if (!clock) { >> mci_writel(host, CLKENA, 0); >> > > >