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>

drivers/net/e1000e/82571.c

@@ -71,6 +71,7 @@ static s32 e1000_setup_link_82571(struct e1000_hw *hw);
 static void e1000_clear_hw_cntrs_82571(struct e1000_hw *hw);
 static bool e1000_check_mng_mode_82574(struct e1000_hw *hw);
 static s32 e1000_led_on_82574(struct e1000_hw *hw);
+static void e1000_put_hw_semaphore_82571(struct e1000_hw *hw);
 
 /**
  *  e1000_init_phy_params_82571 - Init PHY func ptrs.
@@ -212,6 +213,9 @@ static s32 e1000_init_mac_params_82571(struct e1000_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 	struct e1000_mac_info *mac = &hw->mac;
 	struct e1000_mac_operations *func = &mac->ops;
+	u32 swsm = 0;
+	u32 swsm2 = 0;
+	bool force_clear_smbi = false;
 
 	/* Set media type */
 	switch (adapter->pdev->device) {
@@ -276,6 +280,50 @@ static s32 e1000_init_mac_params_82571(struct e1000_adapter *adapter)
 		break;
 	}
 
+	/*
+	 * Ensure that the inter-port SWSM.SMBI lock bit is clear before
+	 * first NVM or PHY acess. This should be done for single-port
+	 * devices, and for one port only on dual-port devices so that
+	 * for those devices we can still use the SMBI lock to synchronize
+	 * inter-port accesses to the PHY & NVM.
+	 */
+	switch (hw->mac.type) {
+	case e1000_82571:
+	case e1000_82572:
+		swsm2 = er32(SWSM2);
+
+		if (!(swsm2 & E1000_SWSM2_LOCK)) {
+			/* Only do this for the first interface on this card */
+			ew32(SWSM2,
+			    swsm2 | E1000_SWSM2_LOCK);
+			force_clear_smbi = true;
+		} else
+			force_clear_smbi = false;
+		break;
+	default:
+		force_clear_smbi = true;
+		break;
+	}
+
+	if (force_clear_smbi) {
+		/* Make sure SWSM.SMBI is clear */
+		swsm = er32(SWSM);
+		if (swsm & E1000_SWSM_SMBI) {
+			/* This bit should not be set on a first interface, and
+			 * indicates that the bootagent or EFI code has
+			 * improperly left this bit enabled
+			 */
+			hw_dbg(hw, "Please update your 82571 Bootagent\n");
+		}
+		ew32(SWSM, swsm & ~E1000_SWSM_SMBI);
+	}
+
+	/*
+	 * Initialze device specific counter of SMBI acquisition
+	 * timeouts.
+	 */
+	 hw->dev_spec.e82571.smb_counter = 0;
+
 	return 0;
 }
 
@@ -413,11 +461,37 @@ static s32 e1000_get_phy_id_82571(struct e1000_hw *hw)
 static s32 e1000_get_hw_semaphore_82571(struct e1000_hw *hw)
 {
 	u32 swsm;
-	s32 timeout = hw->nvm.word_size + 1;
+	s32 sw_timeout = hw->nvm.word_size + 1;
+	s32 fw_timeout = hw->nvm.word_size + 1;
 	s32 i = 0;
 
+	/*
+	 * If we have timedout 3 times on trying to acquire
+	 * the inter-port SMBI semaphore, there is old code
+	 * operating on the other port, and it is not
+	 * releasing SMBI. Modify the number of times that
+	 * we try for the semaphore to interwork with this
+	 * older code.
+	 */
+	if (hw->dev_spec.e82571.smb_counter > 2)
+		sw_timeout = 1;
+
+	/* Get the SW semaphore */
+	while (i < sw_timeout) {
+		swsm = er32(SWSM);
+		if (!(swsm & E1000_SWSM_SMBI))
+			break;
+
+		udelay(50);
+		i++;
+	}
+
+	if (i == sw_timeout) {
+		hw_dbg(hw, "Driver can't access device - SMBI bit is set.\n");
+		hw->dev_spec.e82571.smb_counter++;
+	}
 	/* Get the FW semaphore. */
-	for (i = 0; i < timeout; i++) {
+	for (i = 0; i < fw_timeout; i++) {
 		swsm = er32(SWSM);
 		ew32(SWSM, swsm | E1000_SWSM_SWESMBI);
 
@@ -428,9 +502,9 @@ static s32 e1000_get_hw_semaphore_82571(struct e1000_hw *hw)
 		udelay(50);
 	}
 
-	if (i == timeout) {
+	if (i == fw_timeout) {
 		/* Release semaphores */
-		e1000e_put_hw_semaphore(hw);
+		e1000_put_hw_semaphore_82571(hw);
 		hw_dbg(hw, "Driver can't access the NVM\n");
 		return -E1000_ERR_NVM;
 	}
@@ -449,9 +523,7 @@ static void e1000_put_hw_semaphore_82571(struct e1000_hw *hw)
 	u32 swsm;
 
 	swsm = er32(SWSM);
-
-	swsm &= ~E1000_SWSM_SWESMBI;
-
+	swsm &= ~(E1000_SWSM_SMBI | E1000_SWSM_SWESMBI);
 	ew32(SWSM, swsm);
 }
 

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 */

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 {