From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [PATCH] mmc: dw_mmc: Add a timeout for sending CMD11 Date: Fri, 13 Mar 2015 20:19:39 +0900 Message-ID: <5502C7CB.3010504@samsung.com> References: <1425943101-11976-1-git-send-email-dianders@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout2.samsung.com ([203.254.224.25]:59090 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754068AbbCMLTm (ORCPT ); Fri, 13 Mar 2015 07:19:42 -0400 In-reply-to: <1425943101-11976-1-git-send-email-dianders@chromium.org> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Doug Anderson , Jaehoon Chung , Seungwon Jeon , Ulf Hansson Cc: Addy Ke , Heiko Stuebner , Andrew Bresticker , linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, chris@printf.net, linux-rockchip@lists.infradead.org, Alim Akhtar , Sonny Rao , javier.martinez@collabora.co.uk, linux-arm-kernel@lists.infradead.org, Alexandru Stan Hi Doug. This patch is a right process. Just i wonder something. On 03/10/2015 08:18 AM, Doug Anderson wrote: > In the Designware databook's description of the "Voltage Switch Normal > Scenario" it instructs us to set a timer and fail the voltage change > if we don't see the voltage change interrupt within 2ms. Let's > implement that. Without implementing this I have often been able to > reproduce a hang while trying to send CMD11 on an rk3288-based board > while constantly ejecting and inserting UHS cards. > > Signed-off-by: Doug Anderson > --- > drivers/mmc/host/dw_mmc.c | 26 ++++++++++++++++++++++++++ > include/linux/mmc/dw_mmc.h | 2 ++ > 2 files changed, 28 insertions(+) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 47dfd0e..d259662 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -1020,6 +1020,15 @@ static void __dw_mci_start_request(struct dw_mci *host, > > dw_mci_start_command(host, cmd, cmdflags); > > + if (cmd->opcode == SD_SWITCH_VOLTAGE) { > + /* > + * Databook says to fail after 2ms w/ no response; give an > + * extra jiffy just in case we're about to roll over. > + */ > + mod_timer(&host->cmd11_timer, > + jiffies + msecs_to_jiffies(2) + 1); What's "plus one"? > + } > + > if (mrq->stop) > host->stop_cmdr = dw_mci_prepare_command(slot->mmc, mrq->stop); > else > @@ -2158,6 +2167,8 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id) > /* Check volt switch first, since it can look like an error */ > if ((host->state == STATE_SENDING_CMD11) && > (pending & SDMMC_INT_VOLT_SWITCH)) { > + del_timer(&host->cmd11_timer); > + > mci_writel(host, RINTSTS, SDMMC_INT_VOLT_SWITCH); > pending &= ~SDMMC_INT_VOLT_SWITCH; > dw_mci_cmd_interrupt(host, pending); > @@ -2571,6 +2582,18 @@ ciu_out: > return ret; > } > > +static void dw_mci_cmd11_timer(unsigned long arg) > +{ > + struct dw_mci *host = (struct dw_mci *)arg; > + > + if (host->state != STATE_SENDING_CMD11) > + dev_info(host->dev, "Unexpected CMD11 timeout\n"); If Unexpected CMD11 timeout, can it do just" return"? Well, I think Unexpected CMD11 timeout is an rare case. Best Regards, Jaehoon Chung > + > + host->cmd_status = SDMMC_INT_RTO; > + set_bit(EVENT_CMD_COMPLETE, &host->pending_events); > + tasklet_schedule(&host->tasklet); > +} > + > #ifdef CONFIG_OF > static struct dw_mci_of_quirks { > char *quirk; > @@ -2745,6 +2768,9 @@ int dw_mci_probe(struct dw_mci *host) > } > } > > + setup_timer(&host->cmd11_timer, > + dw_mci_cmd11_timer, (unsigned long)host); > + > host->quirks = host->pdata->quirks; > > spin_lock_init(&host->lock); > diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h > index 471fb31..9efc567 100644 > --- a/include/linux/mmc/dw_mmc.h > +++ b/include/linux/mmc/dw_mmc.h > @@ -202,6 +202,8 @@ struct dw_mci { > int irq; > > int sdio_id0; > + > + struct timer_list cmd11_timer; > }; > > /* DMA ops for Internal/External DMAC interface */ >