I haven't managed to produce a hang without this patch
see also comments below
2015-06-16 12:37 GMT+02:00 Vignesh R <vigneshr@xxxxxx>:
> Usually when there is an error in transfer, DTO/CTO or other error
> interrupts are raised. But if the card is unplugged in the middle of a
> data transfer, it is observed that, neither completion(success) or
> timeout(error) interrupts are raised. Hence, the mmc-core is waiting
> for-ever for the transfer to complete. This results failure to recognise
> sd card on the next insertion.
> The only way to solve this is to introduce code to detect this condition
> and recover on card insertion (in hsmmc specific cd_irq). Hence,
> introduce cd_irq and add code to clear mmc_request that is pending from
> the failed transaction.
>
> Signed-off-by: Vignesh R <vigneshr@xxxxxx>
> ---
> drivers/mmc/host/omap_hsmmc.c | 73 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 72 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index fb4bfefd9250..ec1fff3c0c9c 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -221,6 +221,12 @@ struct omap_hsmmc_host {
> #define HSMMC_WAKE_IRQ_ENABLED (1 << 2)
> struct omap_hsmmc_next next_data;
> struct omap_hsmmc_platform_data *pdata;
> + /*
> + * flag to determine whether card was removed during data
> + * transfer
> + */
> + bool transfer_incomplete;
> +
>
> /* return MMC cover switch state, can be NULL if not supported.
> *
> @@ -867,6 +873,26 @@ static void omap_hsmmc_request_done(struct omap_hsmmc_host *host, struct mmc_req
> }
>
> /*
> + * Cleanup incomplete card removal sequence. This will make sure the
> + * next card enumeration is clean.
> + */
> +static void omap_hsmmc_request_clear(struct omap_hsmmc_host *host,
> + struct mmc_request *mrq)
> +{
> + unsigned long flags;
> +
> + spin_lock_irqsave(&host->irq_lock, flags);
> + host->req_in_progress = 0;
> + host->dma_ch = -1;
> + spin_unlock_irqrestore(&host->irq_lock, flags);
> +
> + mmc_request_done(host->mmc, mrq);
> + if (host->mmc->card)
> + mmc_card_set_removed(host->mmc->card);
> + host->mrq = NULL;
> +}
> +
> +/*
> * Notify the transfer complete to MMC core
> */
> static void
> @@ -1248,6 +1274,47 @@ static irqreturn_t omap_hsmmc_cover_irq(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> +/*
> + * irq handler to notify the core about card insertion/removal
> + */
> +static irqreturn_t omap_hsmmc_cd_irq(int irq, void *dev_id)
> +{
Move this code to 'omap_hsmmc_get_cd' function. Or rather clear
any pending transfer upon '.init_card/omap_hsmmc_init_card'
I guess other hosts also have some housekeeping upon unexpected
card removals. So I guess there is some generic code to this problem.
Did you check?
> + struct omap_hsmmc_host *host = mmc_priv(dev_id);
> + int carddetect = mmc_gpio_get_cd(host->mmc);
> + struct mmc_request *mrq = host->mrq;
> +
> + /*
> + * If the card was removed in the middle of data transfer last
> + * time, the TC/CC/timeout interrupt is not raised due to which
> + * mmc_request is not cleared. Hence, this card insertion will
> + * still see pending mmc_request. Clear the request to make sure
> + * that this card enumeration is successful.
> + */
> + if (!carddetect && mrq && host->transfer_incomplete) {
> + omap_hsmmc_disable_irq(host);
> + dev_info(host->dev,
> + "card removed during transfer last time\n");
> + hsmmc_command_incomplete(host, -ENOMEDIUM, 1);
> + omap_hsmmc_request_clear(host, host->mrq);
> + dev_info(host->dev, "recovery done\n");
> + }
> + host->transfer_incomplete = false;
> +
> + mmc_detect_change(host->mmc, (HZ * 200) / 1000);
> +
> + /*
> + * The current mmc_request is usually null before card removal
> + * sequence is complete. It may not be null if TC/CC interrupt
> + * never happens due to removal of card during a data
> + * transfer. Set a flag to indicate mmc_request was not null
> + * in order to do cleanup on next card insertion.
> + */
> + if (carddetect && mrq)
> + host->transfer_incomplete = true;
> +
> + return IRQ_HANDLED;
> +}
> +
> static void omap_hsmmc_dma_callback(void *param)
> {
> struct omap_hsmmc_host *host = param;
> @@ -1918,7 +1985,7 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
> struct mmc_host *mmc;
> struct omap_hsmmc_host *host = NULL;
> struct resource *res;
> - int ret, irq;
> + int ret, irq, len;
> const struct of_device_id *match;
> dma_cap_mask_t mask;
> unsigned tx_req, rx_req;
> @@ -1980,6 +2047,10 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
> if (ret)
> goto err_gpio;
>
> + /* register cd_irq, if cd-gpios property is specified in dt */
> + if (of_find_property(host->dev->of_node, "cd-gpios", &len))
> + mmc_gpio_set_cd_isr(mmc, omap_hsmmc_cd_irq);
> +
nack, this is done by mmc_of_parse
> platform_set_drvdata(pdev, host);
>
> if (pdev->dev.of_node)
> --
> 2.4.1
>
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