e1000e: workaround invalid Tx/Rx tail descriptor register write

When the Manageability Engine (ME) is enabled on 82579, it periodically
accesses some MAC CSR registers.  There is an arbiter in hardware which
prevents simultaneous access of these registers by the host software, i.e.
the driver.  There is a hardware bug in the aribter that signals a host
access of the registers later than it actually happens.  A write of the
Transmit or Receive Descriptor Tail register could result in an incorrect
value if the driver and ME perform simultaneous accesses which could result
in an access to an invalid memory address.  This would return an
Unsupported Request which could hang the hardware.  Workaround the issue by
checking the FWSM register bit24 which is set by ME before it accesses the
MAC CSR registers.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h
index 35916f485028..8533ad7f3559 100644
--- a/drivers/net/e1000e/e1000.h
+++ b/drivers/net/e1000e/e1000.h
@@ -155,6 +155,9 @@ struct e1000_info;
 #define HV_M_STATUS_SPEED_1000            0x0200
 #define HV_M_STATUS_LINK_UP               0x0040
 
+#define E1000_ICH_FWSM_PCIM2PCI		0x01000000 /* ME PCIm-to-PCI active */
+#define E1000_ICH_FWSM_PCIM2PCI_COUNT	2000
+
 /* Time to wait before putting the device into D3 if there's no link (in ms). */
 #define LINK_TIMEOUT		100
 
@@ -454,6 +457,7 @@ struct e1000_info {
 #define FLAG2_DISABLE_AIM                 (1 << 8)
 #define FLAG2_CHECK_PHY_HANG              (1 << 9)
 #define FLAG2_NO_DISABLE_RX               (1 << 10)
+#define FLAG2_PCIM2PCI_ARBITER_WA         (1 << 11)
 
 #define E1000_RX_DESC_PS(R, i)	    \
 	(&(((union e1000_rx_desc_packet_split *)((R).desc))[i]))