Subject: [PATCH] mmc: dw_mmc: add quirk for data over interrupt timeout

From: [email-masked] (Jaehoon Chung)
Date: Fri, 14 Nov 2014 22:18:24 +0900

Hi, Addy.

Did you use the DW_MCI_QUIRK_IDMAC_DTO?
I'm not sure, but i wonder if you get what result when you use above quirk.

And i will check more this patch at next week.

Thanks for your efforts.

Best Regards,
Jaehoon Chung

On 11/14/2014 10:05 PM, Addy Ke wrote:
> From: Addy <[email-masked]>
> 
> This patch add a new quirk to notify the driver to teminate
> current transfer and report a data timeout to the core,
> if data over interrupt does NOT come within the given time.
> 
> dw_mmc call mmc_request_done func to finish transfer depends on
> data over interrupt. If data over interrupt does not come in
> sending data state, the current transfer will be blocked.
> 
> But this case really exists, when driver reads tuning data from
> card on rk3288-pink2 board. I measured waveforms by oscilloscope
> and found that card clock was always on and data lines were always
> holded high level in sending data state. This is the cause that
> card does NOT send data to host.
> 
> According to synopsys designware databook, the timeout counter is
> started only after the card clock is stopped.
> 
> So if card clock is always on, data read timeout interrupt will NOT come,
> and if data lines are always holded high level, all data-related
> interrupt such as start-bit error, data crc error, data over interrupt,
> end-bit error, and so on, will NOT come too.
> 
> So driver can't get the current state, it can do nothing but wait for.
> 
> This patch is based on https://patchwork.kernel.org/patch/5227941/
> 
> Signed-off-by: Addy <[email-masked]>
> ---
>  drivers/mmc/host/dw_mmc.c  | 47 +++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/mmc/dw_mmc.h |  5 +++++
>  2 files changed, 51 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index b4c3044..3960fc3 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1448,6 +1448,17 @@ static int dw_mci_data_complete(struct dw_mci *host, struct mmc_data *data)
>  	return data->error;
>  }
>  
> +static inline void dw_mci_dto_start_monitor(struct dw_mci *host)
> +{
> +	unsigned int data_tmout_clks;
> +	unsigned int data_tmout_ms;
> +
> +	data_tmout_clks = (mci_readl(host, TMOUT) >> 8);
> +	data_tmout_ms = (data_tmout_clks * 1000 / host->bus_hz) + 250;
> +
> +	mod_timer(&host->dto_timer, jiffies + msecs_to_jiffies(data_tmout_ms));
> +}
> +
>  static void dw_mci_tasklet_func(unsigned long priv)
>  {
>  	struct dw_mci *host = (struct dw_mci *)priv;
> @@ -1522,8 +1533,11 @@ static void dw_mci_tasklet_func(unsigned long priv)
>  			}
>  
>  			if (!test_and_clear_bit(EVENT_XFER_COMPLETE,
> -						&host->pending_events))
> +						&host->pending_events)) {
> +				if (host->quirks & DW_MCI_QUIRK_DTO_TIMER)
> +					dw_mci_dto_start_monitor(host);
>  				break;
> +			}
>  
>  			set_bit(EVENT_XFER_COMPLETE, &host->completed_events);
>  
> @@ -2115,6 +2129,9 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
>  		}
>  
>  		if (pending & SDMMC_INT_DATA_OVER) {
> +			if (host->quirks & DW_MCI_QUIRK_DTO_TIMER)
> +				del_timer(&host->dto_timer);
> +
>  			mci_writel(host, RINTSTS, SDMMC_INT_DATA_OVER);
>  			if (!host->data_status)
>  				host->data_status = pending;
> @@ -2502,6 +2519,28 @@ ciu_out:
>  	return ret;
>  }
>  
> +static void dw_mci_dto_timer(unsigned long arg)
> +{
> +	struct dw_mci *host = (struct dw_mci *)arg;
> +
> +	switch (host->state) {
> +	case STATE_SENDING_DATA:
> +	case STATE_DATA_BUSY:
> +		/*
> +		* If data over interrupt does NOT come in sending data state,
> +		* we should notify the driver to teminate current transfer
> +		* and report a data timeout to the core.
> +		*/
> +		host->data_status = SDMMC_INT_DRTO;
> +		set_bit(EVENT_DATA_ERROR, &host->pending_events);
> +		set_bit(EVENT_DATA_COMPLETE, &host->pending_events);
> +		tasklet_schedule(&host->tasklet);
> +		break;
> +	default:
> +		break;
> +	}
> +}
> +
>  #ifdef CONFIG_OF
>  static struct dw_mci_of_quirks {
>  	char *quirk;
> @@ -2513,6 +2552,9 @@ static struct dw_mci_of_quirks {
>  	}, {
>  		.quirk	= "disable-wp",
>  		.id	= DW_MCI_QUIRK_NO_WRITE_PROTECT,
> +	}, {
> +		.quirk	= "dto-timer",
> +		.id	= DW_MCI_QUIRK_DTO_TIMER,
>  	},
>  };
>  
> @@ -2654,6 +2696,9 @@ int dw_mci_probe(struct dw_mci *host)
>  
>  	spin_lock_init(&host->lock);
>  	INIT_LIST_HEAD(&host->queue);
> +	if (host->quirks & DW_MCI_QUIRK_DTO_TIMER)
> +		setup_timer(&host->dto_timer,
> +			    dw_mci_dto_timer, (unsigned long)host);
>  
>  	/*
>  	 * Get the host data width - this assumes that HCON has been set with
> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
> index 42b724e..2477813 100644
> --- a/include/linux/mmc/dw_mmc.h
> +++ b/include/linux/mmc/dw_mmc.h
> @@ -98,6 +98,7 @@ struct mmc_data;
>   * @irq_flags: The flags to be passed to request_irq.
>   * @irq: The irq value to be passed to request_irq.
>   * @sdio_id0: Number of slot0 in the SDIO interrupt registers.
> + * @dto_timer: Timer for data over interrupt timeout.
>   *
>   * Locking
>   * =======
> @@ -196,6 +197,8 @@ struct dw_mci {
>  	int			irq;
>  
>  	int			sdio_id0;
> +
> +	struct timer_list	dto_timer;
>  };
>  
>  /* DMA ops for Internal/External DMAC interface */
> @@ -220,6 +223,8 @@ struct dw_mci_dma_ops {
>  #define DW_MCI_QUIRK_BROKEN_CARD_DETECTION	BIT(3)
>  /* No write protect */
>  #define DW_MCI_QUIRK_NO_WRITE_PROTECT		BIT(4)
> +/* Timer for data over interrupt timeout */
> +#define DW_MCI_QUIRK_DTO_TIMER			BIT(5)
>  
>  /* Slot level quirks */
>  /* This slot has no write protect */
>