lkml.org 
[lkml]   [2015]   [Mar]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mmc: dw_mmc: Add a timeout for sending CMD11
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 <dianders@chromium.org>
> ---
> 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 */
>



\
 
 \ /
  Last update: 2015-03-13 12:41    [W:0.042 / U:12.088 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site