[U-Boot] [PATCH 1/3] mmc: dw_mmc: change the read/write order under fifo mode

[Ziyuan Xu]

hi Jaehoon,


On 2016年08月30日 17:54, Jaehoon Chung wrote:
> Hi Jacob,
>
> On 08/30/2016 02:26 AM, Jacob Chen wrote:
>> From: "jacob2.chen" <jacob2.chen at rock-chips.com>
>>
>> The former implement have a bug.
>> It will cause wrong data reading sometimes.
> Could you explain what bug is there?
>>
>> Signed-off-by: jacob2.chen <jacob2.chen at rock-chips.com>
> Could you change from jacob2.chen to your name?
>
>> ---
>>
>>   drivers/mmc/dw_mmc.c | 32 +++++++++++++++++---------------
>>   1 file changed, 17 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
>> index afc674d..f072739 100644
>> --- a/drivers/mmc/dw_mmc.c
>> +++ b/drivers/mmc/dw_mmc.c
>> @@ -120,35 +120,37 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data)
>>   
>>   		if (host->fifo_mode && size) {
>>   			len = 0;
>> -			if (data->flags == MMC_DATA_READ) {
>> -				if ((dwmci_readl(host, DWMCI_RINTSTS) &
>> -				     DWMCI_INTMSK_RXDR)) {
>> +			if (data->flags == MMC_DATA_READ &&
>> +			    (mask & DWMCI_INTMSK_RXDR)) {
>> +				while (size) {
>>   					len = dwmci_readl(host, DWMCI_STATUS);
>>   					len = (len >> DWMCI_FIFO_SHIFT) &
>> -						    DWMCI_FIFO_MASK;
>> +					    DWMCI_FIFO_MASK;
> this changing is related with bug?

I just hit this bug on rk3036 board.

When DTO interrupt occurred, there are any remaining data still in FIFO 
due to RX FIFO threshold is larger than remaining data. It also causes 
that dwmmc didn't trigger RXDR interrupt.
It's responsibility of driver to read remaining bytes on seeing DTO 
interrupt. So we need rework dwmci_data_transfer w/ pio mode.

>
>>   					len = min(size, len);
>>   					for (i = 0; i < len; i++)
>>   						*buf++ =
>> -						dwmci_readl(host, DWMCI_DATA);
>> -					dwmci_writel(host, DWMCI_RINTSTS,
>> -						     DWMCI_INTMSK_RXDR);
>> +						    dwmci_readl(host,
>> +								DWMCI_DATA);
>> +					size = size > len ? (size - len) : 0;
>>   				}
>> -			} else {
>> -				if ((dwmci_readl(host, DWMCI_RINTSTS) &
>> -				     DWMCI_INTMSK_TXDR)) {
>> +				dwmci_writel(host, DWMCI_RINTSTS,
>> +					     DWMCI_INTMSK_RXDR);
>> +			} else if (data->flags == MMC_DATA_WRITE &&
>> +				   (mask & DWMCI_INTMSK_TXDR)) {
> data->flags == MMC_DATA_WRITE doesn't need..flags are only two..
> one is MMC_DATA_READ, otherwise it's MMC_DATA_WRITE.
>
>> +				while (size) {
>>   					len = dwmci_readl(host, DWMCI_STATUS);
>>   					len = fifo_depth - ((len >>
>> -						   DWMCI_FIFO_SHIFT) &
>> -						   DWMCI_FIFO_MASK);
>> +							     DWMCI_FIFO_SHIFT) &
>> +							    DWMCI_FIFO_MASK);
> ditto.
>
> Best Regards,
> Jaehoon Chung
>
>>   					len = min(size, len);
>>   					for (i = 0; i < len; i++)
>>   						dwmci_writel(host, DWMCI_DATA,
>>   							     *buf++);
>> -					dwmci_writel(host, DWMCI_RINTSTS,
>> -						     DWMCI_INTMSK_TXDR);
>> +					size = size > len ? (size - len) : 0;
>>   				}
>> +				dwmci_writel(host, DWMCI_RINTSTS,
>> +					     DWMCI_INTMSK_TXDR);
>>   			}
>> -			size = size > len ? (size - len) : 0;
>>   		}
>>   
>>   		/* Data arrived correctly. */
>>
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