net: mvneta: driver for Marvell Armada 370/XP network unit

This patch contains a new network driver for the network unit of the
ARM Marvell Armada 370 and the Armada XP. Both SoCs use the PJ4B
processor, a Marvell-developed ARM core that implements the ARMv7
instruction set.

Compared to previous ARM Marvell SoCs (Kirkwood, Orion, Discovery),
the network unit in Armada 370 and Armada XP is highly different. This
is the reason why this new 'mvneta' driver is needed, while the older
ARM Marvell SoCs use the 'mv643xx_eth' driver.

Here is an overview of the most important hardware changes that
require a new, specific, driver for the network unit of Armada 370/XP:

 - The new network unit has a completely different design and layout
   for the RX and TX descriptors. They are now organized as a simple
   array (each RX and TX queue has base address and size of this
   array) rather than a linked list as in the old SoCs.

 - The new network unit has a different RXQ and TXQ management: this
   management is done using special read/write counter registers,
   while in the Old SocS, it was done using the Ownership bit in RX
   and TX descriptors.

 - The new network unit has different interrupt registers

 - The new network unit way of cleaning of interrupts is not done by
   writing to the cause register, but by updating per-queue counters

 - The new network unit has different GMAC registers (link, speed,
   duplex configuration) and different WRR registers.

 - The new network unit has lots of new units like PnC (Parser and
   Classifier), PMT, BM (Memory Buffer Management), xPON, and more.

The driver proposed in the current patch only handles the basic
features. Additional hardware features will progressively be supported
as needed.

This code has originally been written by Rami Rosen
<rosenr@marvell.com>, and then reviewed and cleaned up by Thomas
Petazzoni <thomas.petazzoni@free-electrons.com>.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/marvell-armada-370-neta.txt

@@ -0,0 +1,23 @@
+* Marvell Armada 370 / Armada XP Ethernet Controller (NETA)
+
+Required properties:
+- compatible: should be "marvell,armada-370-neta".
+- reg: address and length of the register set for the device.
+- interrupts: interrupt for the device
+- phy: A phandle to a phy node defining the PHY address (as the reg
+  property, a single integer).
+- phy-mode: The interface between the SoC and the PHY (a string that
+  of_get_phy_mode() can understand)
+- clock-frequency: frequency of the peripheral clock of the SoC.
+
+Example:
+
+ethernet@d0070000 {
+	compatible = "marvell,armada-370-neta";
+	reg = <0xd0070000 0x2500>;
+	interrupts = <8>;
+	clock-frequency = <250000000>;
+	status = "okay";
+	phy = <&phy0>;
+	phy-mode = "rgmii-id";
+};

drivers/net/ethernet/marvell/Kconfig

@@ -42,6 +42,19 @@ config MVMDIO
 	  (used on Armada 370 and XP), but it could be used in the
 	  future by the MV643XX_ETH driver.
 
+config MVNETA
+	tristate "Marvell Armada 370/XP network interface support"
+	depends on MACH_ARMADA_370_XP
+	select PHYLIB
+	select MVMDIO
+	---help---
+	  This driver supports the network interface units in the
+	  Marvell ARMADA XP and ARMADA 370 SoC family.
+
+	  Note that this driver is distinct from the mv643xx_eth
+	  driver, which should be used for the older Marvell SoCs
+	  (Dove, Orion, Discovery, Kirkwood).
+
 config PXA168_ETH
 	tristate "Marvell pxa168 ethernet support"
 	depends on CPU_PXA168

drivers/net/ethernet/marvell/Makefile

@@ -4,6 +4,7 @@
 
 obj-$(CONFIG_MV643XX_ETH) += mv643xx_eth.o
 obj-$(CONFIG_MVMDIO) += mvmdio.o
+obj-$(CONFIG_MVNETA) += mvneta.o
 obj-$(CONFIG_PXA168_ETH) += pxa168_eth.o
 obj-$(CONFIG_SKGE) += skge.o
 obj-$(CONFIG_SKY2) += sky2.o