e1000e: disable far-end loopback mode on ESB2
The ESB2 LAN includes a debug feature that enables far-end loopback (FELB)
of the SerDes/Kumeran interface. This feature is activated when receiving
a sequence of symbols that includes a reserved codeword. On a perfect
link, FELB would never be activated. In the presence of bit errors, there
is a very small, but non-zero, probability of FELB being activated.
If the FELB is activated, the SerDes link becomes non-functional and must
be reset. It could also corrupt the switching tables in the switch since
the ESB2 is transmitting packets with a different source MAC address.
This patch disables the FELB feature.
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/e1000e/es2lan.c b/drivers/net/e1000e/es2lan.c
index f4bbeb2..c0ecb2d 100644
--- a/drivers/net/e1000e/es2lan.c
+++ b/drivers/net/e1000e/es2lan.c
@@ -836,6 +836,7 @@
struct e1000_mac_info *mac = &hw->mac;
u32 reg_data;
s32 ret_val;
+ u16 kum_reg_data;
u16 i;
e1000_initialize_hw_bits_80003es2lan(hw);
@@ -861,6 +862,13 @@
/* Setup link and flow control */
ret_val = e1000e_setup_link(hw);
+ /* Disable IBIST slave mode (far-end loopback) */
+ e1000_read_kmrn_reg_80003es2lan(hw, E1000_KMRNCTRLSTA_INBAND_PARAM,
+ &kum_reg_data);
+ kum_reg_data |= E1000_KMRNCTRLSTA_IBIST_DISABLE;
+ e1000_write_kmrn_reg_80003es2lan(hw, E1000_KMRNCTRLSTA_INBAND_PARAM,
+ kum_reg_data);
+
/* Set the transmit descriptor write-back policy */
reg_data = er32(TXDCTL(0));
reg_data = (reg_data & ~E1000_TXDCTL_WTHRESH) |