Mark Kettenis authored Jan 21, 2023 and Tom Rini committed Jan 27, 2023

An XHCI controller that sits behind an IOMMU needs to map and unmap
its memory buffers to do DMA.  Implement this by inroducing new
xhci_dma_map() and xhci_dma_unmap() helper functions.  The
xhci_dma_map() function replaces the existing xhci_virt_to_bus()
function in the sense that it returns the bus address in the case
of simple address translation in the absence of an IOMMU.  The
xhci_bus_to_virt() function is eliminated by storing the CPU
address of the allocated scratchpad memory in struct xhci_ctrl.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
Reviewed-by: Marek Vasut <marex@denx.de>