The DMA transfer routine was computing the start of the DMA area by
taking the address of the coherent allocation, and then adding the
transfer's start offset. It then checked manually that the upper bound
was valid.
Convert this to an I/O projection of the same region, which returns
`ERANGE` if the passed range does not fit within the coherent
allocation. This removes the need to perform arithmetic on DMA addresses
and to explicitly check for the bounds' validity.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://patch.msgid.link/20260805-falcon-dma-projections-v2-3-4cc9f3f13ee9@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
4c9ba40701