[RESEND PATCH v1 1/1] mmc: fix response timeout after switch command

[Stefan Bosch]

Hi,

On 27.01.21 00:38, Jaehoon Chung wrote:
> Hi,
> 
> On 1/23/21 9:37 PM, Stefan Bosch wrote:
>> After issuing the switch command: Wait until 'current state' of the card
>> status becomes 'tran'. This prevents from response timeout at the next
>> command because of 'current state' = 'data'.>
>> Signed-off-by: Stefan Bosch <stefan_b at posteo.net>
>> ---
>>
>>   drivers/mmc/mmc.c | 3 ++-
>>   include/mmc.h     | 1 +
>>   2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
>> index a47700e313..8ccd2058a9 100644
>> --- a/drivers/mmc/mmc.c
>> +++ b/drivers/mmc/mmc.c
>> @@ -823,7 +823,8 @@ static int __mmc_switch(struct mmc *mmc, u8 set, u8 index, u8 value,
>>   				 value);
>>   			return -EIO;
>>   		}
>> -		if (!ret && (status & MMC_STATUS_RDY_FOR_DATA))
>> +		if (!ret && (status & MMC_STATUS_RDY_FOR_DATA) &&
>> +		    (status & MMC_STATUS_CURR_STATE) == MMC_STATE_TRANS)
> 
> AFAIK, MMC_STATUS_RDY_FOR_DATA bit means the signaling about "buffer is empty".
> Even though its bit was set, does it need to check TRANS state?
> 
> Best Regards,
> Jaehoon Chung
> 

After issuing command 'MMC_CMD_SWITCH' = CMD6 the state transits to 
'DATA'. But in DATA state it is not possible to issue a (new) CMD except 
CMD12 (operation complete) and CMD7 (select/deselect card). See 
appropriate State Diagram, e.g. "Figure 4-3: SD Memory Card State 
Diagram (data transfer mode)" in "SD Specifications Part 1 - Physical 
Layer - Simplified Specification - Version 2.00". Status 'Ready For 
Data' is in my opinion only relevant for CMD12 and CMD7.

Regards
Stefan Bosch

>>   			return 0;
>>   		udelay(100);
>>   	} while (get_timer(start) < timeout_ms);
>> diff --git a/include/mmc.h b/include/mmc.h
>> index 1d377e0281..18402494c6 100644
>> --- a/include/mmc.h
>> +++ b/include/mmc.h
>> @@ -178,6 +178,7 @@ static inline bool mmc_is_tuning_cmd(uint cmdidx)
>>   #define MMC_STATUS_ERROR	(1 << 19)
>>   
>>   #define MMC_STATE_PRG		(7 << 9)
>> +#define MMC_STATE_TRANS		(4 << 9)
>>   
>>   #define MMC_VDD_165_195		0x00000080	/* VDD voltage 1.65 - 1.95 */
>>   #define MMC_VDD_20_21		0x00000100	/* VDD voltage 2.0 ~ 2.1 */
>>
>