[U-Boot] Question AT91SAM9G20 boot from SD

[Albin Tonnerre]

On Fri, Sep 04, 2009 at 07:38:15PM +0200, Konrad Mattheis wrote :
> >> Hi,
> >> 
> >> I have a AT91SAM9G20 and try to boot from SD-Card.
> >> I compiled u-boot, but the CONFIG_MMC is missing in the default mode.
> >> I found the default config for this board in 
> >> /include/config/at91sam9260ek.h there I added the follofing lines:
> >> 
> >> #define CONFIG_CMD_MMC 1
> >> #define CONFIG_MMC 1
> >> 
> >> now I get a compiler error with:
> >> 
> >> /common/cmd_mmc.c:53: undefined reference to `mmc_legacy_init',.....
> >> 
> >> Any ideas?
> 
> >You need an actual SD/MMC driver. Here, the driver is atmel_mci, and you need #define CONFIG_ATMEL_MCI in your board >config.h
> 
> >Please note, though, that using the MCI driver on AT91 is not yet supported in mainline.
> 
> What does is mean, not yet. Do you have a plan to support this. Or is this a dead-end street?

As per the thread I pointed[1] out to you, there is an actual plan to support
it, as the first mail suggests. That's a patch which implements such support,
and is currently pending review...

Please note that the atmel_mci is currently buggy for little-endian
architectures (that is, at91), and needs fixing in that regard. One way to fix
this was posted by Sami Kantoluoto in the first mail on [2], and a second way,
as explained in the first reply to [2]

[1] http://lists.denx.de/pipermail/u-boot/2009-September/059665.html
[2] http://lists.denx.de/pipermail/u-boot/2009-August/059595.html

Regards,
-- 
Albin Tonnerre, Free Electrons
Kernel, drivers and embedded Linux development,
consulting, training and support.
http://free-electrons.com
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