+/**\r
+ This is a callback routine supplied to UNDI at undi_start time.\r
+ UNDI call this routine when it wants synchronize the virtual buffer contents\r
+ with the mapped buffer contents. The virtual and mapped buffers need not\r
+ correspond to the same physical memory (especially if the virtual address is\r
+ > 4GB). Depending on the direction for which the buffer is mapped, undi will\r
+ need to synchronize their contents whenever it writes to/reads from the buffer\r
+ using either the cpu address or the device address.\r
+\r
+ EFI does not provide a sync call, since virt=physical, we sould just do\r
+ the synchronization ourself here!\r
+\r
+ @param UniqueId This was supplied to UNDI at Undi_Start, SNP uses this to store\r
+ Undi interface context (Undi does not read or write this variable)\r
+ @param CpuAddr Virtual address that was mapped!\r
+ @param NumBytes size of memory mapped.\r
+ @param Direction direction of data flow for this memory's usage:\r
+ cpu->device, device->cpu or both ways.\r
+ @param DeviceAddr the mapped device address.\r
+\r
+**/\r