Create API to map between CPU physical and bus addresses
On some SoCs, DMA-capable peripherals see a different address space to
the CPU's physical address space. Create an API to allow platform-agnostic
drivers to convert between the two address spaces when programming DMA
operations.
This API will exist on all platforms, but will have a dummy implementation
when this feature is not required. Other platforms will enable
CONFIG_PHYS_TO_BUS and provide the required implementation.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
diff --git a/drivers/Kconfig b/drivers/Kconfig
index dcce532..941aa0c 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -53,3 +53,11 @@
source "drivers/thermal/Kconfig"
endmenu
+
+config PHYS_TO_BUS
+ bool
+ help
+ Some SoCs use a different address map for CPU physical addresses and
+ peripheral DMA master accesses. If yours does, select this option in
+ your platform's Kconfig, and implement the appropriate mapping
+ functions in your platform's support code.