Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751366AbbBJPXb (ORCPT ); Tue, 10 Feb 2015 10:23:31 -0500 Received: from mail-qa0-f47.google.com ([209.85.216.47]:65109 "EHLO mail-qa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750823AbbBJPX3 (ORCPT ); Tue, 10 Feb 2015 10:23:29 -0500 MIME-Version: 1.0 In-Reply-To: <1423466726-20833-2-git-send-email-addy.ke@rock-chips.com> 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> From: Alim Akhtar Date: Tue, 10 Feb 2015 20:52:47 +0530 Message-ID: Subject: Re: [PATCH v2 1/2] mmc: dw_mmc: fix bug that cause 'Timeout sending command' To: Addy Ke Cc: "robh+dt" , pawel.moll@arm.com, Mark Rutland , ijc+devicetree@hellion.org.uk, galak@codeaurora.org, rdunlap@infradead.org, Seungwon Jeon , Jaehoon Chung , Chris Ball , Ulf Hansson , dinguyen@altera.com, =?UTF-8?Q?Heiko_St=C3=BCbner?= , Olof Johansson , Douglas Anderson , Sonny Rao , amstan@chromium.org, djkurtz@chromium.org, huangtao@rock-chips.com, "devicetree@vger.kernel.org" , hl@rock-chips.com, linux-doc@vger.kernel.org, yzq@rock-chips.com, zyw@rock-chips.com, zhangqing@rock-chips.com, "linux-mmc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , kever.yang@rock-chips.com, lintao@rock-chips.com, linux-rockchip@lists.infradead.org, xjq@rock-chips.com, zhenfu.fang@rock-chips.com, chenfen@rock-chips.com, cf@rock-chips.com, hj@rock-chips.com, "linux-arm-kernel@lists.infradead.org" , zyf@rock-chips.com Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3511 Lines: 98 Hi Addy, On Mon, Feb 9, 2015 at 12:55 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); > + Why 500 msec? > + 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); > + Why you need to reset all blocks? may be CTRL_RESET is good enough here. > + /* 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); > hmm...I would suggest you to call dw_mci_wait_busy() from inside mci_send_cmd(), seems like dw_mmc hangs while sending update clock cmd in multiple cases.see [1] [1]: http://permalink.gmane.org/gmane.linux.kernel.mmc/31140 > if (!clock) { > mci_writel(host, CLKENA, 0); > -- > 1.8.3.2 > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- Regards, Alim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/