gianfar: add support for SGMII

Add code for initialising and configuring TBI interface and
programming it for connecting to on-chip SERDES (Lynx PHY)
in case of SGMII mode selected through HRCW at reset.

also add defines for TBI register configuration. TBI
interface is programmed towards the SERDES.

refactored mdio read/write functions to differentiate
programming local interface MII regs (e.g., for TBI) from
always programming the mdio master (TSEC1, for programming
the PHYs).

Signed-off-by: Kapil Juneja <Kapil.Juneja@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h
index 39e9e32..d8e779c 100644
--- a/drivers/net/gianfar.h
+++ b/drivers/net/gianfar.h
@@ -136,6 +136,12 @@
 #define MIIMCFG_RESET           0x80000000
 #define MIIMIND_BUSY            0x00000001
 
+/* TBI register addresses */
+#define MII_TBICON		0x11
+
+/* TBICON register bit fields */
+#define TBICON_CLK_SELECT	0x0020
+
 /* MAC register bits */
 #define MACCFG1_SOFT_RESET	0x80000000
 #define MACCFG1_RESET_RX_MC	0x00080000