e1000e: Fixes possible phy corrupton on 82571 designs.

Phy corruption has been observed on 2-port 82571 adapters, and is root-caused
to lack of synchronization between the 2 driver instances, which conflict
when attempting to access the phy via the single MDIC register.
A semaphore exists for this purpose, and is now used on these designs. Because
PXE &/or EFI boot code (which we cannot expect to be built with this fix) may
leave the inter-instance semaphore in an invalid initial state when the driver
first loads, this fix also includes a one-time (per driver load) fix-up of the
semaphore initial state.

Signed-off-by: dave graham <david.graham@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/e1000e/defines.h b/drivers/net/e1000e/defines.h
index 674a47e43034..8890c97e1120 100644
--- a/drivers/net/e1000e/defines.h
+++ b/drivers/net/e1000e/defines.h
@@ -376,6 +376,8 @@
 #define E1000_SWSM_SWESMBI      0x00000002 /* FW Semaphore bit */
 #define E1000_SWSM_DRV_LOAD     0x00000008 /* Driver Loaded Bit */
 
+#define E1000_SWSM2_LOCK        0x00000002 /* Secondary driver semaphore bit */
+
 /* Interrupt Cause Read */
 #define E1000_ICR_TXDW          0x00000001 /* Transmit desc written back */
 #define E1000_ICR_LSC           0x00000004 /* Link Status Change */