OHCI1394_IsoRecvIntMaskClear
reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, 0xffffffff);
reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, 1 << index);
reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, ~0);