The implementation of dma_map_single() and dma_unmap_single() is
exactly the same for all the architectures that support them.
Factor them out to <linux/dma-mapping.h>, and make all drivers to
include <linux/dma-mapping.h> instead of <asm/dma-mapping.h>.
If we need to differentiate them for some architectures, we can
move the generic definitions to <asm-generic/dma-mapping.h>.
Add some comments to the helpers. The concept is quite similar to
the DMA-API of Linux kernel. Drivers are agnostic about what is
going on behind the scene. Just call dma_map_single() before the
DMA, and dma_unmap_single() after it.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Subsystems such as USB expect dma_map_single() and dma_unmap_single() to
do dcache flush/invalidate operations as required. For example, see
see drivers/usb/gadget/udc/udc-core.c::usb_gadget_map_request().
Currently drivers do this locally, (see drivers/usb/dwc3/ep0.c,
drivers/mtd/nand/raw/denali.c etc..)
Update arch specific dma_map_single() and dma_unmap_single() APIs to do
cache flush/invalidate operations, so that drivers need not implement
them locally.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Rick Chen <rick@andestech.com>
This patch adds asm/dma-mapping.h for Linux-like DMA mappings
APIs required by some of the drivers (such as, Cadance MACB
Ethernet driver).
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
