Beaglebone black - omap4 mcspi interrupts do not appear

Hello bbb community,

I am an open source enthusiast and I am trying to port
omap4 mcspi drivers to Xenomai real-time linux.
  After I set CS active and enable channel 0 and interrupts,
I receive only two interrupts (in fact a pair):
- tx0_empty and after this I fill the mcspi tx reg with data and reset
the flag in IRQSTATUS
- as a follow up to the actions taken for tx0_empty,
rx0_full interrupt is risen and I read the mcspi rx reg and reset the
flag in IRQSTATUS.
After that no interrupt comes (neither of tx_empty, rx_full or EOT)
even if interrupts and channel0 are enabled and CS is active,
so I can not transfer remaining data.
FIFO is enabled and OMAP2_MCSPI_XFERLEVEL is setup accordingly to transfer size.
  If I use the polling method to see if something is pending
everything works well, but I need real-time,
so must use interrupts.
  The dts for spi0 and spi1 is not changed.

  Any ideas?

Thank you,
L-C. Duca