This patch allows devices that require memory that can be addressed
using 32-bit addresses to work easily on RISC-V systems. The newly
improved dma-direct ops will tap into this pool automatically for
32-bit addressing.
Based on an earlier patch from Wesley W. Terpstra.
CC: Wesley W. Terpstra <terpstra@sifive.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>