I have an EDK/SDK design where I use the xilfatfs drivers to read from a compact-flash card.
When I start reading, initially I see good results; data is coming back. However, after several read-cycles, the PPC freezes and does not come back.
If you are using OPB SysAce version 1.00.b, upgrade it to OPB SysAce version 1.00.c. Decrease the PPC Clock Frequency to 100 MHz to match the hardware and increase the Stack and Heap sizes as necessary.