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so-lli1
Adventurer
Adventurer
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Registered: ‎11-26-2016

ZynqMP - JTAG Port open error. AP transaction timeout

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It is not possible to recover the system using JTAG and XSDB. Not even a reset is possible, it always returns "AP transaction timeout". How can this be fixed without a power cycle of the whole board?

Regards,
so-lli1

 

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stephenm
Xilinx Employee
Xilinx Employee
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Registered: ‎09-12-2007

Do you know the root cause of the issue that is causing this hang? This will occur if you try to access an mem/reg that doent exist.

If the kernal is hanged, then there may not be a solution other than a power cycle. Even if you do a successful reset, and you dont have isolation enabled,

then the system could potential hang if there is an outstanding AXI transaction (for example).

 

 

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stephenm
Xilinx Employee
Xilinx Employee
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Registered: ‎09-12-2007

Can you try a software reset. The reboot command in Linux, or devmem 0xff5e0218 0x1e

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so-lli1
Adventurer
Adventurer
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Registered: ‎11-26-2016

Hi @stephenm,

To be honest, I don't understand what you are suggesting. Since there was a kernel panic, there is no linux available. Both of your commands depend on linux.

However, I tried JTAG access with XSDB to recover without success. As far as I understand issuing "rst -system" command is equivalent to writing to the 0xff5e0218 (RESET_CTRL) register. Tried both, neither worked.

 

Edit: In order to reproduce, I simply stopped in the u-boot console. JTAG reset... is not working any more, so there must be something I am not aware of that grants the uboot control and blocks me out on JTAG somehow.

Hopefully someone can shed some light on this.

Thanks

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stephenm
Xilinx Employee
Xilinx Employee
1,006 Views
Registered: ‎09-12-2007

Do you know the root cause of the issue that is causing this hang? This will occur if you try to access an mem/reg that doent exist.

If the kernal is hanged, then there may not be a solution other than a power cycle. Even if you do a successful reset, and you dont have isolation enabled,

then the system could potential hang if there is an outstanding AXI transaction (for example).

 

 

View solution in original post

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so-lli1
Adventurer
Adventurer
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Registered: ‎11-26-2016

@stephenm 

Turns out the board I am working with has some pre-production silicon on it and needs to be treated with special care. However, thank you very much for your explanation.

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