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

[Jaehoon Chung]

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?

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;
>   }
>