driver: net: ethernet: cpsw: dual emac interface implementation

The CPSW switch can act as Dual EMAC by segregating the switch ports
using VLAN and port VLAN as per the TRM description in
14.3.2.10.2 Dual Mac Mode

Following CPSW components will be common for both the interfaces.
* Interrupt source is common for both eth interfaces
* Interrupt pacing is common for both interfaces
* Hardware statistics is common for all the ports
* CPDMA is common for both eth interface
* CPTS is common for both the interface and it should not be enabled on
  both the interface as timestamping information doesn't contain port
  information.

Constrains
* Reserved VID of One port should not be used in other interface which will
  enable switching functionality
* Same VID must not be used in both the interface which will enable switching
  functionality
Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/cpsw.txt

@@ -24,6 +24,8 @@ Required properties:
 Optional properties:
 - ti,hwmods		: Must be "cpgmac0"
 - no_bd_ram		: Must be 0 or 1
+- dual_emac		: Specifies Switch to act as Dual EMAC
+- dual_emac_res_vlan	: Specifies VID to be used to segregate the ports
 
 Note: "ti,hwmods" field is used to fetch the base address and irq
 resources from TI, omap hwmod data base during device registration.

include/linux/platform_data/cpsw.h

@@ -21,6 +21,8 @@ struct cpsw_slave_data {
 	char		phy_id[MII_BUS_ID_SIZE];
 	int		phy_if;
 	u8		mac_addr[ETH_ALEN];
+	u16		dual_emac_res_vlan;	/* Reserved VLAN for DualEMAC */
+
 };
 
 struct cpsw_platform_data {
@@ -36,6 +38,7 @@ struct cpsw_platform_data {
 	u32	rx_descs;	/* Number of Rx Descriptios */
 	u32	mac_control;	/* Mac control register */
 	u16	default_vlan;	/* Def VLAN for ALE lookup in VLAN aware mode*/
+	bool	dual_emac;	/* Enable Dual EMAC mode */
 };
 
 #endif /* __CPSW_H__ */