Data transfer from Nios to FPGA using Avalon-MM

I'm trying to transfer data from Nios to FPGA fabric using the Avalon Memory Mapped interface (where Nios is the master and the FPGA being the slave).

This is my Nios C code

I use IOWR_ALTERA_AVALON_FIFO_DATA to write data to the FIFO from Nios.

Is there a way to check if the data (0x0A) is actually written to the FIFO? If so, is this statement
printf("return data: %d\n", IORD_ALTERA_AVALON_FIFO_DATA(FIFO_2_OUT_BASE));
the right way to do it? Because I am unable to read the same value.