dm: Introduce DMA constraints into the core device model
Calculating the DMA offset between a bus address space and CPU's every
time we call phys_to_bus() and bus_to_phys() isn't ideal performance
wise, as it implies traversing the device tree from the device's node up
to the root. Since this information is static and available before the
device's initialization, parse it before the probe call an provide the
DMA offset in 'struct udevice' for the address translation code to use
it.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index dbfe51c..00554af 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -129,6 +129,16 @@
This applies to several ofnode functions (see ofnode.h) which are
seldom used. Inlining them can help reduce code size.
+config DM_DMA
+ bool "Support per-device DMA constraints"
+ depends on DM
+ default n
+ help
+ Enable this to extract per-device DMA constraints, only supported on
+ device-tree systems for now. This is needed in order translate
+ addresses on systems where different buses have different views of
+ the physical address space.
+
config REGMAP
bool "Support register maps"
depends on DM