[U-Boot] Help with Glomation GESBC-9G20

[Larry Baker]

Bo and Andreas,

Thank you all for your guidance.  I had no idea the primary bootstrap might also have to be upgraded.

Andreas had a concern about the partition size for U-Boot.  The latest releases are near the limit for the current flash partition layout.  However, I believe there is 128 Kb available for U-Boot to expand -- the env partitions would have to slide up.  But, the primary boot loader has to know that as well.  Is there a way to know the U-Boot partition size the at91loader expects?  I don't know the version Glomation ships.  The U-Boot they ship is a patched 1.3.4-exp5 -- I assume one of the first, if not the first, to support AT91 SAM SoCs.  They are both pretty old, I think.

I've been working on this project at night and weekends because I don't have the time (and it is not my boss's priority) during the day.  I really want to get a UBIFS root file system on this board.  But, I haven't figured out how to do that yet, nor have I found a rootfs small enough to fit yet.  Then, there are the actual apps I want to run (real-time earthquake data acquisition).  Too much (interesting and challenging) work!

Thank you,

Larry Baker
US Geological Survey
650-329-5608
baker at usgs.gov




On Jun 24, 2013, at 1:22 AM, Bo Shen wrote:

> Hi Larry Baker,
> 
> On 6/24/2013 16:02, Larry Baker wrote:
>> I have found why the latest U-Boot does not work on my Glomation GESBC-9G20 board.  Two causes: a bad code text segment address (prevents U-Boot from executing) and bad flash partition offsets (prevents U-Boot from reading its environment variables).  The latter I assume is common, as the flash partition layout can vary.  The former has to do with where the primary boot loader expects to find U-Boot's entry point.  The primary boot loader comes from Atmel, I believe, and I assume does not change.  Yet, the 2011.06 release of U-Boot changed that address.  (FYI: the two immediately preceding releases, 2010.12 and 2011.03, fail to compile with configuration errors.  There were definitely changes taking place during that time with the Atmel AT91SAM U-Boot code.)  That may be a bug.  I don't know who the authority on that question would be.  If it is decided the U-Boot code text segment address is incorrect, it wold be nice to fix that in the upcoming release.  (If there is time.)
> 
> For the text base, why we use 0x21f00000 instead of 0x23f00000 is that, the memory only 64MiB on at91sam9g20ek board, if use 0x23f00000 as the text base, there is only 1MiB reserved for u-boot use. So, we move down to let more space for u-boot.
> 
> For the NAND partition, as to the u-boot grow bigger and bigger, so we reserve more space for it.
> 
> BTW, when you upgrade the u-boot, please also upgrade the bootstrap. we always keep the update bootstrap work with mainline u-boot properly.
> 
> Best Regards,
> Bo Shen
>