net: stmmac: sunxi platform extensions for GMAC in Allwinner A20 SoC's

The Allwinner A20 has an ethernet controller that seems to be
an early version of Synopsys DesignWare MAC 10/100/1000 Universal,
which is supported by the stmmac driver.

Allwinner's GMAC requires setting additional registers in the SoC's
clock control unit.

The exact version of the DWMAC IP that Allwinner uses is unknown,
thus the exact feature set is unknown.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index b59d1ef..e2f202e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
@@ -26,6 +26,17 @@
 
 	  If unsure, say N.
 
+config DWMAC_SUNXI
+	bool "Allwinner GMAC support"
+	depends on STMMAC_PLATFORM && ARCH_SUNXI
+	default y
+	---help---
+	  Support for Allwinner A20/A31 GMAC ethernet controllers.
+
+	  This selects Allwinner SoC glue layer support for the
+	  stmmac device driver. This driver is used for A20/A31
+	  GMAC 	  ethernet controller.
+
 config STMMAC_PCI
 	bool "STMMAC PCI bus support"
 	depends on STMMAC_ETH && PCI