[U-Boot] mmc1 not working on Samsung snow chromebook

[Jaehoon Chung]

Hi,

On 2017년 11월 16일 21:29, Guillaume Gardet wrote:
> I found a workaround. If I disable MMC_MODE_HS_52MHz, then it is working fine.
> 
> I guess there is a better way to implement the following patch ?
> 
> **********************************************************************
> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> index 23f642980b..a6a0934eef 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;
> +       /* MMC_MODE_HS_52MHz is broken (at least) on Samsung Snow, so disbale it for now */
> +       cfg->host_caps |= MMC_MODE_HS;

It means that card is running the lower clock frequency..it's not solution.
Timing issue and some problems should be fixed with lowest frequency.

Now, i can't test and check more detail. After back to my office or home, i will check what main cause.

Best Regards,
Jaehoon Chung

> 
>         cfg->b_max = CONFIG_SYS_MMC_MAX_BLK_COUNT;
>  }
> **********************************************************************
> 
> 
> Guillaume
> 
> 
> 
> Le 15/11/2017 à 11:27, Guillaume Gardet a écrit :
>>
>>
>> Le 15/11/2017 à 11:22, Guillaume Gardet a écrit :
>>> Forgot to Cc ML. Done now.
>>>
>>>
>>> Le 15/11/2017 à 11:14, Guillaume Gardet a écrit :
>>>> Hello,
>>>>
>>>> I tested U-Boot v2017.09 on a Samsung Snow (Chromebook ARM) and while mmc0 (internal eMMC) is working fine, mmc1 (external SD slot) does not work.
>>>> I get the following error for 'mmc dev 1' command:
>>>>     mmc_init: -110, time 30
>>
>> Please also note that on boot (or on 1st 'mmc dev 1' cmd if I stop auto-boot), I firstly get:
>>     mmc_init: -5, time 39
>>
>> Then, all next attempts retruns:
>>     mmc_init: -110, time 30
>>
>>
>> Guillaume
>>
>>
>>>>
>>>> Any idea what could be wrong?
>>>>
>>>> Guillaume
>>>>
>>>>
>>>
>>
> 
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