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

[Guillaume Gardet <guillaume.gardet@free.fr>]

Hi Jaehoon,


Le 26/04/2018 à 15:15, Guillaume Gardet a écrit :
>
>
> 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.

Any progress on this problem?

Guillaume

>
>
> 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;
>>>    }
>>>
>>
>