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/hw.h b/drivers/net/e1000e/hw.h
index fce3f0529e4c..163c1c0cfee7 100644
--- a/drivers/net/e1000e/hw.h
+++ b/drivers/net/e1000e/hw.h
@@ -214,6 +214,7 @@ enum e1e_registers {
         E1000_FACTPS    = 0x05B30, /* Function Active and Power State to MNG */
         E1000_SWSM      = 0x05B50, /* SW Semaphore */
         E1000_FWSM      = 0x05B54, /* FW Semaphore */
+        E1000_SWSM2     = 0x05B58, /* Driver-only SW semaphore */
         E1000_HICR      = 0x08F00, /* Host Interface Control */
 };
 
@@ -883,6 +884,7 @@ struct e1000_fc_info {
 struct e1000_dev_spec_82571 {
         bool laa_is_present;
         bool alt_mac_addr_is_present;
+        u32 smb_counter;
 };
 
 struct e1000_shadow_ram {