At91bootstrap boot on SAM9260-EK

AT91SAM9 Evaluation Boards

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andre.zheng
Posts: 2
Joined: Wed Aug 20, 2014 1:57 pm

At91bootstrap boot on SAM9260-EK

Wed Aug 20, 2014 2:09 pm

Hi, I'm porting OS on Atmel's SAM9260-EK which is mounted with AT91SAM9260 QFP-208 chip but not BGA version chip.

At current step, the at91bootstrap still failed to be ported on SAM9260-EK. I've tried to programmed the at91bootstrap.bin into nandflash. And the at91bootstrap's version is the latest one I downloaded from git server and used at91sam9260eknf_uboot_defconfig configuration. Also I did enable the DEBUG print and make sure all the binary image is within 4KB.

After I programmed the at91bootstrap.bin into nandflash by using SAM-BA, it only outputted with "ROMBOOT >" but nothing else. I've tried to using SAMSUNG's nandflash and MICRON's nandflash, but always with the same output. My AT91SAM9260's version is 1130 B, this shall be the REV B chip and supporting the nandflash boot, right?

Any comment about this issue? I really don't know what's to do next. Every suggestion is appreciated. Thanks!
andre.zheng
Posts: 2
Joined: Wed Aug 20, 2014 1:57 pm

Re: At91bootstrap boot on SAM9260-EK

Wed Aug 20, 2014 2:11 pm

We could see from the DEBUG port output, the SAM-BA could recognize the nandflash chip ID. So the hardware connection to the nandflash shall be ok.
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blue_z
Location: USA
Posts: 1547
Joined: Thu Apr 19, 2007 10:15 pm

Re: At91bootstrap boot on SAM9260-EK

Wed Aug 20, 2014 10:18 pm

andre.zheng wrote:So the hardware connection to the nandflash shall be ok.
Just because you can erase the Flash does not mean that it is fully functional.
For that you at least need an actual write-then-read test.
Maybe you should be adapting the Soft Pack code examples into diagnostics to test out the board.

Or download and install the precompiled boot & kernel binaries to demonstrate that your EK board is functional.

After installing AT91Bootstrap, be sure to validate the write.
Verify the 28-byte ARM exception vector, especially the word repurposed to store the byte length of the binary image.
andre.zheng wrote:And the at91bootstrap's version is the latest one I downloaded from git server
Instead of using the git head, download an actual released version which is identifiable and repeatable.

What toolchain/compiler are you using?
Did you read the README.txt file?
Is the toolchain that you used in the list of proven toolchains?
From personal experience: the "wrong" compiler can generate boot code that will hang the processor.

Regards
dh6325_home
Posts: 1
Joined: Tue Aug 26, 2014 6:04 am

Re: At91bootstrap boot on SAM9260-EK

Tue Aug 26, 2014 6:13 am

I am also having this issue with a custom board based largely on the AT91SAM9260-EK. This board has been in production for a few years. We store the AT91bootstrap and U-Boot in dataflash, and the Linux kernel as well as our own applications in NAND flash. Clearly the NAND flash is fully functional on this board. We are considering switching to booting completely from NAND flash, so I am trying to get that to work, but I am getting the same symptoms described here with any version of AT91bootstrap that I build for NAND flash.

What's interesting is that if I put the dataflash version of AT91bootstrap in NAND flash, the system will boot it. That is, it spits out the usual stuff, then loads U-Boot from dataflash. Just to be clear, the sequence is this:

- Connect up with SAM-BA
- Erase dataflash
- Send u-boot.bin to 0x8400 in dataflash
- Erase NAND flash
- Send boot file (at91sam9260ek-dataflashboot-uboot-3.6.2.bin)
- Reset the board

This works and loads U-Boot (2nd level boot from NAND flash, 3rd level boot from dataflash).

However, if I substitute the file at91sam9260ek-nandflashboot-uboot-3.6.2.bin, I don't get any AT91bootstrap spew on the debug port, and the RomBOOT> appears and spits out again every 16 seconds due to the MPU watchdog. If the bootstrap code is not recognized at all (same as both dataflash and NAND flash being erased), you get the RomBOOT>, but it only appears once because the watchdog is apparently disabled by the monitor. So I conclude that the NAND flash version of AT91bootstrap is indeed getting copied over to internal SRAM, but it is not executing or crashing for some reason.

In the at91sam9260ek-nandflashboot-uboot-3.6.2.bin file, the ARM exception vectors are identical to the dataflash version, other than the length at offset 0x14 which is also correct (according to the SAM9260 datasheet this is not necessary for NAND flash anyhow as it always loads 4096 bytes). The size of the file is under the 4K limit.

I am building AT91bootstrap using "arm-buildroot-linux-uclibcgnueabi-gcc version 4.7.3 (Buildroot 2013.08.01)". I tried building an older version of AT91bootstrap (the same one we were already using, built for dataflash), but the binary is too large, and I can't see anything to pare down. I am going to continue to explore the toolchain/bootstrap version path and see if I can find something that works. 

Still, it seems odd that, using the same toolchain and AT91bootstrap source, the dataflash version runs fine (albeit loading u-boot from dataflash instead of NAND), but the NAND flash version doesn't seem to do anything at all.
 
blue_z
Location: USA
Posts: 1547
Joined: Thu Apr 19, 2007 10:15 pm

Re: At91bootstrap boot on SAM9260-EK

Wed Aug 27, 2014 12:45 am

dh6325_home wrote:So I conclude that the NAND flash version of AT91bootstrap is indeed getting copied over to internal SRAM, but it is not executing or crashing for some reason.
It would be silly to test a "conclusion", but can you attach a JTAG probe to test your assumption?

You mention a singular "board". So you only have one board to test?
Are there NAND bad blocks in the bootloaders' partition(s)?

Regards

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