2009-01-08 12:01:28     How to debug when there's nothing on serial console

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2009-01-08 12:01:28     How to debug when there's nothing on serial console

Sajith T S (INDIA)

Message: 67631   

 

Maybe I'm stating the problem wrong, I am not sure.  I had a perfectly (yeah!) working u-boot 1.1.6 for a custom bf536 development board; all of a sudden it stopped working. I've heard that usually under these circumstances software guys would blame hardware, hardware guys would blame software, and it'd go on a little.  But in this case I can't blame hardware, becase u-boot 1.1.3 installed in flash continues to work normally.

 

 

This is what I do -- download u-boot 1.1.6 using tftp, run it off memory.

 

bf537> tftp 0x10000 u-boot.bin

Using MAC Address 00:AA:AA:BB:BB:DD

TFTP from server 192.168.50.79; our IP address is 192.168.50.80

Filename 'u-boot.bin'.

Load address: 0x10000

Loading: ##########################

done

Bytes transferred = 130388 (1fd54 hex)

bf537> go 0x10000

## Starting application at 0x00010000 ...

 

And then nothing happens.  It's just stuck there.

 

I have tried different boot modes, turning off/on icache/dcache, tried different memory sizes, tried bf536 and bf537 targets, turning POST on/off... no luck.  Also, normally you'd continue with whatever working version of bootloader you have, but in this case I can't -- for some mysterious reason, I can't load the kernel + root file system with 1.1.3.  That used to work with my 1.1.6 last week.  I don't have an LED or something on this board that can be turned off/on before relocation, so I'm sort of at my wits' ends.

 

I'm new to this embedded linux thing.  And since this is a custom board I guess I'm pretty much on my own; so I'd like to ask for general debugging wisdom here.  What do people normally do in such a situation?  Connect a CRO or jtag cable or something and probe for magic blue smoke?

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2009-01-08 12:07:12     Re: How to debug when there's nothing on serial console

Mike Frysinger (UNITED STATES)

Message: 67632   

 

please consult the docs:

http://docs.blackfin.uclinux.org/doku.php?id=bootloaders:u-boot:debugging

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2009-01-08 12:30:58     Re: How to debug when there's nothing on serial console

Sajith T S (INDIA)

Message: 67633   

 

Thank you Mike.  I'd been reading that, actually.  In fact I came here since I'm stuck.  I also guessed that since the section on "Debug Options" (DEBUG_DUMP, DEBUG_EARLY_SERIAL etc couldn't be spotted in all of u-boot code) seems to be a bit out of sync, maybe I can find out more by asking.

 

I also don't have a jtag cable that could work with linux tools.  Only this USB-ICE cable.

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2009-01-08 12:44:09     Re: How to debug when there's nothing on serial console

Sajith T S (INDIA)

Message: 67634   

 

I also could not figure out bfin-elf-gcc (where do I find that?  I have bfin-uclinux-gcc and bfin-linux-uclibc-gcc..); and there was no cpu/blackfin/initcode.o either. (There's a call to initcode in the init.S snippey there, but I could find no such routine.)

 

Thought there's no risk in asking. :-)

 

 

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2009-01-08 12:46:49     Re: How to debug when there's nothing on serial console

Mike Frysinger (UNITED STATES)

Message: 67635   

 

the options are up to sync with the 2008R1.5 release.  the documentation reflects the latest release and beyond only.

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2009-01-08 12:47:25     Re: How to debug when there's nothing on serial console

Mike Frysinger (UNITED STATES)

Message: 67636   

 

the bfin-elf toolchain is an optional addon that is part of the toolchain.  you can find packages for it in the toolchain project.

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2009-01-09 00:40:51     Re: How to debug when there's nothing on serial console

Sajith T S (INDIA)

Message: 67649   

 

Thank you Mike.  You are right about the release.  I have some early serial messages now, and almost have an idea of what's going wrong.

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2009-01-09 00:46:57     Re: How to debug when there's nothing on serial console

Sajith T S (INDIA)

Message: 67650   

 

Ouch, can't believe I missed that.  Thank you.

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