powerpc/T4240QDS/eth: some fix for XFI

XFI is supported on T4QDS-XFI board, which removed slot3, and four LANEs
of serdes2 are routed to a SFP+ cages, which to house fiber cable or
direct attach cable(copper), the copper cable is used to emulate the
10GBASE-KR scenario.

So, for XFI usage, there are two scenarios, one will use fiber cable,
another will use copper cable. For fiber cable, there is NO PHY, while
for copper cable, we need to use internal PHY which exist in Serdes to
do auto-negotiation and link training, which implemented in kernel.
We use hwconfig to define cable type for XFI, and fixup dtb based on the
cable type.

For copper cable, set below env in hwconfig:

fsl_10gkr_copper:<10g_mac_name>

the <10g_mac_name> can be fm1_10g1, fm1_10g2, fm2_10g1, fm2_10g2. The
four <10g_mac_name>s do not have to be coexist in hwconfig. For XFI ports,
if a given 10G port will use the copper cable for 10GBASE-KR, set the
<10g_mac_name> of the port in hwconfig, otherwise, fiber cable will be
assumed to be used for the port.

For ex. if four XFI ports will both use copper cable, the hwconfig
should contain:

fsl_10gkr_copper:fm1_10g1,fm1_10g2,fm2_10g1,fm2_10g2

For fiber cable:

1. give PHY address to a XFI port, otherwise, the XFI ports will not be
available in U-boot, there is no PHY physically for XFI when using fiber
cable, this is just to make U-boot happy and we can use the XFI ports
in U-boot.
2. fixup dtb to use fixed-link in case of fiber cable which has no PHY.
Kernel requests that a MAC must have a PHY or fixed-link.

When using XFI protocol, the MAC 9/10 on FM1 should init as 10G interface.

Change serdes 2 protocol 56 to 55 which has same feature as 56 since 56
is not valid any longer.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/doc/README.t4240qds b/doc/README.t4240qds
index ef8c75f..3962fee 100644
--- a/doc/README.t4240qds
+++ b/doc/README.t4240qds
@@ -79,6 +79,25 @@
 		- High-speed serial flash
 	Two Serial port
 	Four I2C ports
+  XFI
+	XFI is supported on T4QDS-XFI board which removed slot3 and routed
+	four Lanes A/B/C/D to a SFP+ cages, which to house fiber cable or
+	direct attach cable(copper), the copper cable is used to emulate
+	10GBASE-KR scenario.
+	So, for XFI usage, there are two scenarios, one will use fiber cable,
+	another will use copper cable. An hwconfig env "fsl_10gkr_copper" is
+	introduced to indicate a XFI port will use copper cable, and U-boot
+	will fixup the dtb accordingly.
+	It's used as: fsl_10gkr_copper:<10g_mac_name>
+	The <10g_mac_name> can be fm1_10g1, fm1_10g2, fm2_10g1, fm2_10g2, they
+	do not have to be coexist in hwconfig. If a MAC is listed in the env
+	"fsl_10gkr_copper", it will use copper cable, otherwise, fiber cable
+	will be used by default.
+	for ex. set "fsl_10gkr_copper:fm1_10g1,fm1_10g2,fm2_10g1,fm2_10g2" in
+	hwconfig, then both four XFI ports will use copper cable.
+	set "fsl_10gkr_copper:fm1_10g1,fm1_10g2" in hwconfig, then first two
+	XFI ports will use copper cable, the other two XFI ports will use fiber
+	cable.
 
 Memory map
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