net: ethernet: Add a driver for Gemini gigabit ethernet

The Gemini ethernet has been around for years as an out-of-tree
patch used with the NAS boxen and routers built on StorLink
SL3512 and SL3516, later Storm Semiconductor, later Cortina
Systems. These ASICs are still being deployed and brand new
off-the-shelf systems using it can easily be acquired.

The full name of the IP block is "Net Engine and Gigabit
Ethernet MAC" commonly just called "GMAC".

The hardware block contains a common TCP Offload Enginer (TOE)
that can be used by both MACs. The current driver does not use
it.

Cc: Tobias Waldvogel <tobias.waldvogel@gmail.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -1327,8 +1327,10 @@ T:	git git://github.com/ulli-kroll/linux.git
 S:	Maintained
 F:	Documentation/devicetree/bindings/arm/gemini.txt
 F:	Documentation/devicetree/bindings/pinctrl/cortina,gemini-pinctrl.txt
+F:	Documentation/devicetree/bindings/net/cortina,gemini-ethernet.txt
 F:	Documentation/devicetree/bindings/rtc/faraday,ftrtc010.txt
 F:	arch/arm/mach-gemini/
+F:	drivers/net/ethernet/cortina/gemini/*
 F:	drivers/pinctrl/pinctrl-gemini.c
 F:	drivers/rtc/rtc-ftrtc010.c
 

drivers/net/ethernet/Kconfig

@@ -42,6 +42,7 @@ source "drivers/net/ethernet/cavium/Kconfig"
 source "drivers/net/ethernet/chelsio/Kconfig"
 source "drivers/net/ethernet/cirrus/Kconfig"
 source "drivers/net/ethernet/cisco/Kconfig"
+source "drivers/net/ethernet/cortina/Kconfig"
 
 config CX_ECAT
 	tristate "Beckhoff CX5020 EtherCAT master support"

drivers/net/ethernet/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_NET_VENDOR_CAVIUM) += cavium/
 obj-$(CONFIG_NET_VENDOR_CHELSIO) += chelsio/
 obj-$(CONFIG_NET_VENDOR_CIRRUS) += cirrus/
 obj-$(CONFIG_NET_VENDOR_CISCO) += cisco/
+obj-$(CONFIG_NET_VENDOR_CORTINA) += cortina/
 obj-$(CONFIG_CX_ECAT) += ec_bhf.o
 obj-$(CONFIG_DM9000) += davicom/
 obj-$(CONFIG_DNET) += dnet.o

drivers/net/ethernet/cortina/Kconfig

@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+# Cortina ethernet devices
+
+config NET_VENDOR_CORTINA
+	bool "Cortina Gemini devices"
+	default y
+	---help---
+	  If you have a network (Ethernet) card belonging to this class, say Y
+	  and read the Ethernet-HOWTO, available from
+	  <http://www.tldp.org/docs.html#howto>.
+
+if NET_VENDOR_CORTINA
+
+config GEMINI_ETHERNET
+	tristate "Gemini Gigabit Ethernet support"
+	depends on OF
+	select PHYLIB
+	select CRC32
+	---help---
+	  This driver supports StorLink SL351x (Gemini) dual Gigabit Ethernet.
+
+endif # NET_VENDOR_CORTINA

drivers/net/ethernet/cortina/Makefile

@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for the Cortina Gemini network device drivers.
+
+obj-$(CONFIG_GEMINI_ETHERNET) += gemini.o