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

From: [email-masked] (Addy)
Date: Tue, 18 Nov 2014 08:32:48 +0800

On 2014?11?14? 21:18, Jaehoon Chung wrote:
> 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.

DW_MCI_QUIRK_IDMAC_DTO is only for version2.0 or below.
         /*
          * DTO fix - version 2.10a and below, and only if internal DMA
          * is configured.
          */
         if (host->quirks & DW_MCI_QUIRK_IDMAC_DTO) {
                 if (!pending &&
                     ((mci_readl(host, STATUS) >> 17) & 0x1fff))
                         pending |= SDMMC_INT_DATA_OVER;
         }

It meams that if interrupt comes, but pending = 0 && FIFO_COUNT(bit17-29) !=0,
then force to set SDMMC_INT_DATA_OVER.
But in our case, FIFO_COUNT = 0 (STATUS register value is 0xad06). This is
because that the card does not send data to host. So there is no interrupts come,
and interrupt handle function(dw_mci_interrupt) will not be called. So we need a
timer to handle this case.

So I think  SDMMC_INT_DATA_OVER is not suitable for this case, and we need a new
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 */
>>
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