DMA IRQ Linux configuring problem

Juan Antonio Medina Guerrero juan-antonio.medina at
Wed Oct 8 18:42:51 EST 2008



      We are facing some issues when trying to implement the interrup-driven
DMA. The function request_irq returns error when trying to use the DMA
interrupt. Following you can find some tests we've performed to try to solve
this trouble:


      - We have been trying various IRQ ID. If we use the spi IRQ_ID the
function request_irq returns error because this IRQ is already being used,
as expected. If we use the usb IRQ_ID the function doesn't return error but
of course doesn't launch the IRQ handle.


      - We have changed the IRQ_ID from USB to DMA in device usb section in
file mpc8313erdb.dts. Then we use dma IRQ_ID and there are launchs of
IRQ_DMA_handler. This method isn't the solution but gives us an idea of the


      - Finally, we make a new device section in dts file but it doesn't
work. We believe that we have created bad the device section or that we need
to do something else. Could you please help us with this?


Kind regards,


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