[U-Boot] [U-Boot, BUG] snow: mmc: SD card access broken: unable to select a mode

[Guillaume Gardet]

Le 26/04/2018 à 12:31, Jaehoon Chung a écrit :
> Hi,
>
> On 04/09/2018 09:02 PM, Guillaume Gardet wrote:
>> Hi Jaehoon,
>>
>> There are problems with SD card access on Samsung Chromebook (snow) with latest master (and also 2018.05-rc1 and 2018.03).
>>
>> eMMC is ok, but SD card access leads to 'unable to select a mode' problem. If I disable HS mode, I can access the SD card without problem:
>> ********************************************************************************
>> ********************************************************************************
>>
>> Once we try to select HS mode, all access to SD card result in failure, even when trying to setup a lower frequency mode, including SD legacy at 25 MHz.
>>
>> Any idea what is going? Maybe you have fixes pending?
> Sorry for late. Hmm. I will check your issue. Just disable MMC_MODE_HS, then it's working fine?
> or HS_52MHz?

I tried to disable HS_52MHz only and it did not fix the problem. Then I tried to disable both HS and HS_52MHz and it fixed the problem.


Guillaume

>
> Best Regards,
> Jaehoon Chung
>
>>
>> Guillaume
>>
>> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
>> index 23f642980bf..28f4fa0f213 100644
>> --- a/drivers/mmc/dw_mmc.c
>> +++ b/drivers/mmc/dw_mmc.c
>> @@ -508,7 +508,8 @@ void dwmci_setup_cfg(struct mmc_config *cfg, struct dwmci_host *host,
>>            cfg->host_caps |= MMC_MODE_4BIT;
>>            cfg->host_caps &= ~MMC_MODE_8BIT;
>>        }
>> -    cfg->host_caps |= MMC_MODE_HS | MMC_MODE_HS_52MHz;
>> +    /* Temp workaround for Chromebook snow to avoid the 'unable to select a mode' error */
>> +//     cfg->host_caps |= MMC_MODE_HS | MMC_MODE_HS_52MHz;
>>
>>        cfg->b_max = CONFIG_SYS_MMC_MAX_BLK_COUNT;
>>    }
>>
>