dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

The Allwinner A31 has a 16 channels DMA controller that it shares with the
newer A23. Although sharing some similarities with the DMA controller of the
older Allwinner SoCs, it's significantly different, I don't expect it to be
possible to share the driver for these two.

The A31 Controller is able to memory-to-memory or memory-to-device transfers on
the 16 channels in parallel.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 1eca7b9..4b43927 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -375,6 +375,14 @@
 	  channels, Memory Mapped to Stream (MM2S) and Stream to
 	  Memory Mapped (S2MM) for the data transfers.
 
+config DMA_SUN6I
+	tristate "Allwinner A31 SoCs DMA support"
+	depends on MACH_SUN6I || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Support for the DMA engine for Allwinner A31 SoCs.
+
 config DMA_ENGINE
 	bool