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Commit d9b24135 authored by Bruce Allan's avatar Bruce Allan Committed by Jeff Kirsher
Browse files

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: default avatarBruce Allan <bruce.w.allan@intel.com>
Tested-by: default avatarAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent e357964e

drivers/net/e1000e/es2lan.c

+8 −0
Original line number Diff line number Diff line
@@ -836,6 +836,7 @@ static s32 e1000_init_hw_80003es2lan(struct e1000_hw *hw) 
	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 @@ static s32 e1000_init_hw_80003es2lan(struct e1000_hw *hw) 
	/* 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) |

drivers/net/e1000e/hw.h

+1 −0
Original line number Diff line number Diff line
@@ -312,6 +312,7 @@ enum e1e_registers { 
#define E1000_KMRNCTRLSTA_DIAG_OFFSET	0x3    /* Kumeran Diagnostic */

#define E1000_KMRNCTRLSTA_TIMEOUTS	0x4    /* Kumeran Timeouts */

#define E1000_KMRNCTRLSTA_INBAND_PARAM	0x9    /* Kumeran InBand Parameters */

#define E1000_KMRNCTRLSTA_IBIST_DISABLE	0x0200 /* Kumeran IBIST Disable */

#define E1000_KMRNCTRLSTA_DIAG_NELPBK	0x1000 /* Nearend Loopback mode */

#define E1000_KMRNCTRLSTA_K1_CONFIG	0x7

#define E1000_KMRNCTRLSTA_K1_ENABLE	0x0002