If the "XHwIcap_CfgInitialize()" function is called immediately after configuration completes, this can result in XST_SUCCESS being set, indicating a failure. This can occur with any programming method. What is the issue here?
Configuration does not fully complete until the Startup state machine has hit the EOS (End of Startup) state. The device can be operational before this, but one function that is gated by EOS is access to the ICAP. The AXI_HWICAP does not handle this error condition correctly and hence results in a failure.
To work around this issue, the STARTUP_SPARTAN6 primitive can be instantiated. This primitive has an output pin EOS that indicates when the device has reached EOS. This can be used to gate access to the ICAP until the device is ready.