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Altera_Forum
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10 years ago

Altera JTAG UART used by kernel does not match IRQ assignment made in Qsys

Hi all, I'm currently developing a 3.10.31-ltsi kernel that running on a Nios II-based system. This system also contains several components including an Altera JTAG UART, USB host controller a...
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Altera_Forum
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10 years ago

Hello Brad,

We did one more test today and here is its result.

case 4 :

Qsys System IRQ assignment: Timer - 2, JTAG - 1

Linux Image IRQ assignment: Timer - 2, JTAG - 1

These results lead us to think that Linux image IRQ assignment differs from that of Qsys IRQ if we have assigned IRQ 0 to some component in Qsys design.

During some further research on internet, we came to know about "irq_create_mapping" function. This functin maps Hardware IRQ into virtual IRQ. More information on this can be found at following : https://www.kernel.org/doc/documentation/irq-domain.txt

We will continue our debug operation and will keep you posted. Meantime, as usual, if you come across any useful item, please share.

Cheers,

Bhaumik