e1000e: Failure to write SHRA turns on PROMISC mode

Previously, the check to turn on promiscuous mode only took into account
the total number of SHared Receive Address (SHRA) registers and if the
request was for a register within that range. It is possible that the
Management Engine might have locked a number of SHRA and not allowed a
new address to be written to the requested register.

Add a function to determine the number of unlocked SHRA registers. Then
determine if the number of registers available is sufficient for our needs,
if not then return -ENOMEM so that UNICAST PROMISC mode is activated.

Since the method by which ME claims SHRA registers is non-deterministic,
also add a return value to the function attempting to write an address
to a SHRA, and return a -E1000_ERR_CONFIG if the write fails. The error
will be passed up the function chain and allow the driver to also set
UNICAST PROMISC when this happens.

Cc: Vlad Yasevich <[e-mail]>
Signed-off-by: Dave Ertman <[e-mail]>
Tested-by: Aaron Brown <[e-mail]>
Signed-off-by: Jeff Kirsher <[e-mail]>

drivers/net/ethernet/intel/e1000e/80003es2lan.c

···
 	.setup_led		= e1000e_setup_led_generic,
 	.config_collision_dist	= e1000e_config_collision_dist_generic,
 	.rar_set		= e1000e_rar_set_generic,
+	.rar_get_count		= e1000e_rar_get_count_generic,
 };
 
 static const struct e1000_phy_operations es2_phy_ops = {

drivers/net/ethernet/intel/e1000e/82571.c

···
 	.config_collision_dist	= e1000e_config_collision_dist_generic,
 	.read_mac_addr		= e1000_read_mac_addr_82571,
 	.rar_set		= e1000e_rar_set_generic,
+	.rar_get_count		= e1000e_rar_get_count_generic,
 };
 
 static const struct e1000_phy_operations e82_phy_ops_igp = {

drivers/net/ethernet/intel/e1000e/hw.h

···
 	s32  (*setup_led)(struct e1000_hw *);
 	void (*write_vfta)(struct e1000_hw *, u32, u32);
 	void (*config_collision_dist)(struct e1000_hw *);
-	void (*rar_set)(struct e1000_hw *, u8 *, u32);
+	int  (*rar_set)(struct e1000_hw *, u8 *, u32);
 	s32  (*read_mac_addr)(struct e1000_hw *);
+	u32  (*rar_get_count)(struct e1000_hw *);
 };
 
 /* When to use various PHY register access functions:

drivers/net/ethernet/intel/e1000e/ich8lan.c

···
 static s32 e1000_set_mdio_slow_mode_hv(struct e1000_hw *hw);
 static bool e1000_check_mng_mode_ich8lan(struct e1000_hw *hw);
 static bool e1000_check_mng_mode_pchlan(struct e1000_hw *hw);
-static void e1000_rar_set_pch2lan(struct e1000_hw *hw, u8 *addr, u32 index);
-static void e1000_rar_set_pch_lpt(struct e1000_hw *hw, u8 *addr, u32 index);
+static int e1000_rar_set_pch2lan(struct e1000_hw *hw, u8 *addr, u32 index);
+static int e1000_rar_set_pch_lpt(struct e1000_hw *hw, u8 *addr, u32 index);
+static u32 e1000_rar_get_count_pch_lpt(struct e1000_hw *hw);
 static s32 e1000_k1_workaround_lv(struct e1000_hw *hw);
 static void e1000_gate_hw_phy_config_ich8lan(struct e1000_hw *hw, bool gate);
 static s32 e1000_disable_ulp_lpt_lp(struct e1000_hw *hw, bool force);
···
 		mac->ops.rar_set = e1000_rar_set_pch_lpt;
 		mac->ops.setup_physical_interface =
 		    e1000_setup_copper_link_pch_lpt;
+		mac->ops.rar_get_count = e1000_rar_get_count_pch_lpt;
 	}
 
 	/* Enable PCS Lock-loss workaround for ICH8 */
···
  *  contain the MAC address but RAR[1-6] are reserved for manageability (ME).
  *  Use SHRA[0-3] in place of those reserved for ME.
  **/
-static void e1000_rar_set_pch2lan(struct e1000_hw *hw, u8 *addr, u32 index)
+static int e1000_rar_set_pch2lan(struct e1000_hw *hw, u8 *addr, u32 index)
 {
 	u32 rar_low, rar_high;
 
···
 		e1e_flush();
 		ew32(RAH(index), rar_high);
 		e1e_flush();
-		return;
+		return 0;
 	}
 
 	/* RAR[1-6] are owned by manageability.  Skip those and program the
···
 		/* verify the register updates */
 		if ((er32(SHRAL(index - 1)) == rar_low) &&
 		    (er32(SHRAH(index - 1)) == rar_high))
-			return;
+			return 0;
 
 		e_dbg("SHRA[%d] might be locked by ME - FWSM=0x%8.8x\n",
 		      (index - 1), er32(FWSM));
···
 
 out:
 	e_dbg("Failed to write receive address at index %d\n", index);
+	return -E1000_ERR_CONFIG;
+}
+
+/**
+ *  e1000_rar_get_count_pch_lpt - Get the number of available SHRA
+ *  @hw: pointer to the HW structure
+ *
+ *  Get the number of available receive registers that the Host can
+ *  program. SHRA[0-10] are the shared receive address registers
+ *  that are shared between the Host and manageability engine (ME).
+ *  ME can reserve any number of addresses and the host needs to be
+ *  able to tell how many available registers it has access to.
+ **/
+static u32 e1000_rar_get_count_pch_lpt(struct e1000_hw *hw)
+{
+	u32 wlock_mac;
+	u32 num_entries;
+
+	wlock_mac = er32(FWSM) & E1000_FWSM_WLOCK_MAC_MASK;
+	wlock_mac >>= E1000_FWSM_WLOCK_MAC_SHIFT;
+
+	switch (wlock_mac) {
+	case 0:
+		/* All SHRA[0..10] and RAR[0] available */
+		num_entries = hw->mac.rar_entry_count;
+		break;
+	case 1:
+		/* Only RAR[0] available */
+		num_entries = 1;
+		break;
+	default:
+		/* SHRA[0..(wlock_mac - 1)] available + RAR[0] */
+		num_entries = wlock_mac + 1;
+		break;
+	}
+
+	return num_entries;
 }
 
 /**
···
  *  contain the MAC address. SHRA[0-10] are the shared receive address
  *  registers that are shared between the Host and manageability engine (ME).
  **/
-static void e1000_rar_set_pch_lpt(struct e1000_hw *hw, u8 *addr, u32 index)
+static int e1000_rar_set_pch_lpt(struct e1000_hw *hw, u8 *addr, u32 index)
 {
 	u32 rar_low, rar_high;
 	u32 wlock_mac;
···
 		e1e_flush();
 		ew32(RAH(index), rar_high);
 		e1e_flush();
-		return;
+		return 0;
 	}
 
 	/* The manageability engine (ME) can lock certain SHRAR registers that
···
 			/* verify the register updates */
 			if ((er32(SHRAL_PCH_LPT(index - 1)) == rar_low) &&
 			    (er32(SHRAH_PCH_LPT(index - 1)) == rar_high))
-				return;
+				return 0;
 		}
 	}
 
 out:
 	e_dbg("Failed to write receive address at index %d\n", index);
+	return -E1000_ERR_CONFIG;
 }
 
 /**
···
 	/* id_led_init dependent on mac type */
 	.config_collision_dist	= e1000e_config_collision_dist_generic,
 	.rar_set		= e1000e_rar_set_generic,
+	.rar_get_count		= e1000e_rar_get_count_generic,
 };
 
 static const struct e1000_phy_operations ich8_phy_ops = {

drivers/net/ethernet/intel/e1000e/mac.c

···
 	return 0;
 }
 
+u32 e1000e_rar_get_count_generic(struct e1000_hw *hw)
+{
+	return hw->mac.rar_entry_count;
+}
+
 /**
  *  e1000e_rar_set_generic - Set receive address register
  *  @hw: pointer to the HW structure
···
  *  Sets the receive address array register at index to the address passed
  *  in by addr.
  **/
-void e1000e_rar_set_generic(struct e1000_hw *hw, u8 *addr, u32 index)
+int e1000e_rar_set_generic(struct e1000_hw *hw, u8 *addr, u32 index)
 {
 	u32 rar_low, rar_high;
 
···
 	e1e_flush();
 	ew32(RAH(index), rar_high);
 	e1e_flush();
+
+	return 0;
 }
 
 /**

drivers/net/ethernet/intel/e1000e/mac.h

···
 void e1000_write_vfta_generic(struct e1000_hw *hw, u32 offset, u32 value);
 
 void e1000_set_lan_id_multi_port_pcie(struct e1000_hw *hw);
-void e1000e_rar_set_generic(struct e1000_hw *hw, u8 *addr, u32 index);
+u32 e1000e_rar_get_count_generic(struct e1000_hw *hw);
+int e1000e_rar_set_generic(struct e1000_hw *hw, u8 *addr, u32 index);
 void e1000e_config_collision_dist_generic(struct e1000_hw *hw);
 
 #endif

drivers/net/ethernet/intel/e1000e/netdev.c

···
 {
 	struct e1000_adapter *adapter = netdev_priv(netdev);
 	struct e1000_hw *hw = &adapter->hw;
-	unsigned int rar_entries = hw->mac.rar_entry_count;
+	unsigned int rar_entries;
 	int count = 0;
+
+	rar_entries = hw->mac.ops.rar_get_count(hw);
 
 	/* save a rar entry for our hardware address */
 	rar_entries--;
···
 		 * combining
 		 */
 		netdev_for_each_uc_addr(ha, netdev) {
+			int rval;
+
 			if (!rar_entries)
 				break;
-			hw->mac.ops.rar_set(hw, ha->addr, rar_entries--);
+			rval = hw->mac.ops.rar_set(hw, ha->addr, rar_entries--);
+			if (rval < 0)
+				return -ENOMEM;
 			count++;
 		}
 	}