[U-Boot] [EXT] [PATCH] arm64: mvebu: armada-8k: support SD card environment

[Baruch Siach]

Hi Kostya,

Thanks for reviewing.

On Thu, Dec 14, 2017 at 11:28:18AM +0000, Kostya Porotchkin wrote:
> > Allow storing the environment on the Macchiatobin SD card. This is
> > useful for distribution of SD card software images. Currently, the
> > environment is always loaded from the SPI flash whose content might be
> > incompatible with SD card kernel loading.
> > 
> > Use the last 64KB of the 32MB boot partition as per the instructions in
> > the Macchiatobin wiki:
> > 
> >   http://wiki.macchiatobin.net/tiki-
> > index.php?page=Setup+alternative+boot+sources
> > 
> > Cc: Konstantin Porotchkin <kostap at marvell.com>
> > Signed-off-by: Baruch Siach <baruch at tkos.co.il>
> > ---
> >  include/configs/mvebu_armada-8k.h | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/include/configs/mvebu_armada-8k.h
> > b/include/configs/mvebu_armada-8k.h
> > index d85527434a0a..0457a72e353b 100644
> > --- a/include/configs/mvebu_armada-8k.h
> > +++ b/include/configs/mvebu_armada-8k.h
> > @@ -73,7 +73,12 @@
> >  #define CONFIG_SF_DEFAULT_MODE		SPI_MODE_0
> >  #define CONFIG_ENV_SPI_MODE		CONFIG_SF_DEFAULT_MODE
> > 
> > +#if defined(CONFIG_ENV_IS_IN_SPI_FLASH)
> >  #define CONFIG_ENV_OFFSET		0x180000 /* as Marvell U-Boot version */
> > +#elif defined(CONFIG_ENV_IS_IN_MMC)
> > +#define CONFIG_SYS_MMC_ENV_DEV		1
> > +#define CONFIG_ENV_OFFSET		0x21f0000
> > +#endif
>
> I think this will break boot from the on-board eMMC device.
> Maybe the environment offset should be connected to the MMC device ID.
> So it will be different for SD and eMMC.
> The eMMC boot partition is not that big as the space on SD allocated for the boot images.
> Additionally, the SD pre-allocated boot space is not really a constant value.

So what would you suggest? How can we detect the location of the SD/eMMC 
stored environment? Would a per-board 'u-boot,mmc-env-offset' DT property 
help? Maybe move to CONFIG_ENV_IS_IN_FAT?

baruch

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