The software code in the gpio_v2_00_a driver includes:
Register = XIIF_V123B_READ_IIER(InstancePtr->BaseAddress +
XIIF_V123B_WRITE_IIER(InstancePtr->BaseAddress + XGPIO_IPIF_OFFSET,
Mask & ~Register);
This should be changed to:
~Mask & Register
This problem has been fixed in the latest EDK 8.1i Service Pack, available at:
The first service pack containing the fix is EDK 8.1i Service Pack 2.