[U-Boot] U-Boot on IMX.51 EVK

[Stefano Babic]

On 01/11/2011 03:02 AM, Thomas Besemer wrote:
> Hi Group -
> 

Hi Thomas,

>   - Is above version of U-Boot known to work on EVK?

As far as I know, yes.

>  It appears that this
> version supports DOS partitions on SD card,

They are additional features, as reading files from a formatted SD is
very common on several boards.

> and default command line is to
> load from those.  But, I can't find any documentation on how to partition
> the SD card to try this.  Help on how to set up the SD card appreciated.

There is some hidden documentation. How to prepare a SD card (partition
table, u-boot image) is described in doc/README.imximage. Getting files
form the SD card is a generic issue, and it is not board specific. You
find examples for fatload in code.

>   - Should above "raw" load from SD work?  Probably my preference, but have
> an open mind.

It should work, but I admit I tested booting from partitions and from
network. Your assumption that CRC is ok let me think that there should
be no problem to read the kernel from the SD card, even in raw mode.

You could verify if your kernel boots independently from storage. Try to
load the kernel from net instead from SD.

>  My Root FS is on two partitions that U-Boot does not need to
> know about;

Correct. u-boot does not need to read the root partition. It is enough
to pass the correct root device to the kernel.

> one is primary/recovery, one is working copy on release.
> 
>   - The Freescale supplied SDK applies over 100 patches to the 8/09 release
> of U-Boot; wondering how many made it into current version of U-Boot, and
> how much I should care.

Rather if they are not pushed to this ML, they cannot be integrated in
the official releases. However, are you sure they are related to the
i.MX51 ? Most of them are probably related to other processors.

>   - I pulled the 2.6.37 Kernel from kernel.org to maybe try that with
> current U-Boot, but it doesn't seem to have IPU support,

I know, but as I see on Linux ARM ML, there is already someone working
on this issue.

> End game:
> 
>   - Get the Splash Screen working on imx.51 EVK.

As reference, take a closer look at the vision2 board. The IPU driver
was ported from Freescale's 2.6.31 linux exactly for this goal. The
splashimage is shown with the help of the "preboot" variable, because
the image is stored on a device not directly addressable (SPI-Flash for
vision2).  It is the same for the mx51evk, because the image must be
loaded (in raw mode or from a partition) from the SD card.

>  I will provide patch set
> back to mailing list once I do.  I will derive from vision2 board.

There is already some work on this issue. A patchset was already sent to
ML, but it requires changes to be included. You could use it as starting
point ;-).

http://www.mail-archive.com/u-boot@lists.denx.de/msg41631.html

Technically, the actual IPU drive in u-boot supports only diu0 (required
by the vision board). So changes are minimal in the IPU driver itself.
However, please read the whole discussion on ML, so you can find which
are the open points to be fixed.

>   - Get it to boot old 2.6.31 SDK supplied Kernel (which also has a bunch of
> Freescale patches that don't seem to have made it into kernel.org).
> 
> Any help on this appreciated; I will be more than happy to provide patch set
> work for anything I do for EVK back to this list for evaluation and
> incorporation.


Best regards,
Stefano Babic

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