u32 i2o_wait_message (struct i2o_controller * c, char * why);
This function waits up to 5 seconds for a message slot to be available. If no message is available it prints an error message that is expected to be what the message will be used for (eg ``get_status''). 0xFFFFFFFF is returned on a failure.
On a success the message is returned. This is the physical page frame offset address from the read port. (See the i2o spec)