On the TX1 platform, flashed using Jetpack 28.1 . Smmu has been enabled. Allocating dma_alloc_coherent memory for PCIE works, and gives a single Bus address that I can use successfully. However trying to remap previously allocated memory using pci_map_sg remaps memory into 64kB chunks with 64kB gaps between them.
mapping 256 4k pages using pc_map_sg gives me back 16 entries. such that each entry maps 64kB of memory and the spacing between subsequent addresses is 128kB.
Is there a reason for this gap> Do I need to change a configuration parameter somewhere to fix this?