Adding esdhc4 eMMC support on mx6sabresd

[Dong Aisheng]

On Fri, May 09, 2014 at 11:16:25AM +0800, Shawn Guo wrote:
> On Thu, May 08, 2014 at 06:17:32PM +0800, Dong Aisheng wrote:
> > I just tested an old Chris/mmc-next tree which is 3.14 rc2 with the top commit is b42b9b.
> > The eMMC works well on SabreSD boards.
> > But it failed and got the same issue with latest chris/mmc-next tree.
> > I noticed there's no changes on sdhci-esdhc-imx.c
> > Probably some other changes breaks this function.
> > 
> > Fabio,
> > You may bisect it yourself or i will do it later when i'm a bit free.
> 
> The regression is caused by the following commit ...
> 
> commit 79f7ae7c45a6ccf04e2908337461dee615f6afb0
> Author: Seungwon Jeon <tgih.jun at samsung.com>
> Date:   Fri Mar 14 21:11:56 2014 +0900
> 
>     mmc: clarify DDR timing mode between SD-UHS and eMMC
> 
>     This change distinguishes DDR timing mode of current
>     mixed usage to clarify device type.
> 
>     Signed-off-by: Seungwon Jeon <tgih.jun at samsung.com>
>     Acked-by: Jaehoon Chung <jh80.chung at samsung.com>
>     Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
>     Signed-off-by: Chris Ball <chris at printf.net>
> 
> ... and the line below.
>  
> @@ -1264,7 +1264,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>                                         goto err;
>                         }
>                         mmc_card_set_ddr_mode(card);
> -                       mmc_set_timing(card->host, MMC_TIMING_UHS_DDR50);
> +                       mmc_set_timing(card->host, MMC_TIMING_MMC_DDR52);
>                         mmc_set_bus_width(card->host, bus_width);
>                 }
>         }
> 

Thanks for the info.
The plat driver is still using UHS_DDR50 which may need update too.
I will submit a patch to fix it ASAP.

Regards
Dong Aisheng

> 
> > Shawn,
> > I remember this patch should have been upstream through your tree long time ago.
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2013-October/206446.html
> > It seems somehow missed.
> 
> Ah, yes.  It got lost.
> 
> Shawn