drivers: add Contiguous Memory Allocator

The Contiguous Memory Allocator is a set of helper functions for DMA
mapping framework that improves allocations of contiguous memory chunks.

CMA grabs memory on system boot, marks it with MIGRATE_CMA migrate type
and gives back to the system. Kernel is allowed to allocate only movable
pages within CMA's managed memory so that it can be used for example for
page cache when DMA mapping do not use it. On
dma_alloc_from_contiguous() request such pages are migrated out of CMA
area to free required contiguous block and fulfill the request. This
allows to allocate large contiguous chunks of memory at any time
assuming that there is enough free memory available in the system.

This code is heavily based on earlier works by Michal Nazarewicz.

Signed-off-by: Marek Szyprowski <[email protected]>
Signed-off-by: Kyungmin Park <[email protected]>
Signed-off-by: Michal Nazarewicz <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Tested-by: Rob Clark <[email protected]>
Tested-by: Ohad Ben-Cohen <[email protected]>
Tested-by: Benjamin Gaignard <[email protected]>
Tested-by: Robert Nelson <[email protected]>
Tested-by: Barry Song <[email protected]>

0 files changed, 0 insertions, 0 deletions