1 files changed, 104 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/igc/igc_mac.c b/drivers/net/ethernet/intel/igc/igc_mac.c
index 5eeb4c8caf4a..12aa6b5fcb5d 100644
--- a/drivers/net/ethernet/intel/igc/igc_mac.c
+++ b/drivers/net/ethernet/intel/igc/igc_mac.c
@@ -784,3 +784,107 @@ bool igc_enable_mng_pass_thru(struct igc_hw *hw)
 out:
 	return ret_val;
 }
+
+/**
+ *  igc_hash_mc_addr - Generate a multicast hash value
+ *  @hw: pointer to the HW structure
+ *  @mc_addr: pointer to a multicast address
+ *
+ *  Generates a multicast address hash value which is used to determine
+ *  the multicast filter table array address and new table value.  See
+ *  igc_mta_set()
+ **/
+static u32 igc_hash_mc_addr(struct igc_hw *hw, u8 *mc_addr)
+{
+	u32 hash_value, hash_mask;
+	u8 bit_shift = 0;
+
+	/* Register count multiplied by bits per register */
+	hash_mask = (hw->mac.mta_reg_count * 32) - 1;
+
+	/* For a mc_filter_type of 0, bit_shift is the number of left-shifts
+	 * where 0xFF would still fall within the hash mask.
+	 */
+	while (hash_mask >> bit_shift != 0xFF)
+		bit_shift++;
+
+	/* The portion of the address that is used for the hash table
+	 * is determined by the mc_filter_type setting.
+	 * The algorithm is such that there is a total of 8 bits of shifting.
+	 * The bit_shift for a mc_filter_type of 0 represents the number of
+	 * left-shifts where the MSB of mc_addr[5] would still fall within
+	 * the hash_mask.  Case 0 does this exactly.  Since there are a total
+	 * of 8 bits of shifting, then mc_addr[4] will shift right the
+	 * remaining number of bits. Thus 8 - bit_shift.  The rest of the
+	 * cases are a variation of this algorithm...essentially raising the
+	 * number of bits to shift mc_addr[5] left, while still keeping the
+	 * 8-bit shifting total.
+	 *
+	 * For example, given the following Destination MAC Address and an
+	 * MTA register count of 128 (thus a 4096-bit vector and 0xFFF mask),
+	 * we can see that the bit_shift for case 0 is 4.  These are the hash
+	 * values resulting from each mc_filter_type...
+	 * [0] [1] [2] [3] [4] [5]
+	 * 01  AA  00  12  34  56
+	 * LSB                 MSB
+	 *
+	 * case 0: hash_value = ((0x34 >> 4) | (0x56 << 4)) & 0xFFF = 0x563
+	 * case 1: hash_value = ((0x34 >> 3) | (0x56 << 5)) & 0xFFF = 0xAC6
+	 * case 2: hash_value = ((0x34 >> 2) | (0x56 << 6)) & 0xFFF = 0x163
+	 * case 3: hash_value = ((0x34 >> 0) | (0x56 << 8)) & 0xFFF = 0x634
+	 */
+	switch (hw->mac.mc_filter_type) {
+	default:
+	case 0:
+		break;
+	case 1:
+		bit_shift += 1;
+		break;
+	case 2:
+		bit_shift += 2;
+		break;
+	case 3:
+		bit_shift += 4;
+		break;
+	}
+
+	hash_value = hash_mask & (((mc_addr[4] >> (8 - bit_shift)) |
+				  (((u16)mc_addr[5]) << bit_shift)));
+
+	return hash_value;
+}
+
+/**
+ *  igc_update_mc_addr_list - Update Multicast addresses
+ *  @hw: pointer to the HW structure
+ *  @mc_addr_list: array of multicast addresses to program
+ *  @mc_addr_count: number of multicast addresses to program
+ *
+ *  Updates entire Multicast Table Array.
+ *  The caller must have a packed mc_addr_list of multicast addresses.
+ **/
+void igc_update_mc_addr_list(struct igc_hw *hw,
+			     u8 *mc_addr_list, u32 mc_addr_count)
+{
+	u32 hash_value, hash_bit, hash_reg;
+	int i;
+
+	/* clear mta_shadow */
+	memset(&hw->mac.mta_shadow, 0, sizeof(hw->mac.mta_shadow));
+
+	/* update mta_shadow from mc_addr_list */
+	for (i = 0; (u32)i < mc_addr_count; i++) {
+		hash_value = igc_hash_mc_addr(hw, mc_addr_list);
+
+		hash_reg = (hash_value >> 5) & (hw->mac.mta_reg_count - 1);
+		hash_bit = hash_value & 0x1F;
+
+		hw->mac.mta_shadow[hash_reg] |= BIT(hash_bit);
+		mc_addr_list += ETH_ALEN;
+	}
+
+	/* replace the entire MTA table */
+	for (i = hw->mac.mta_reg_count - 1; i >= 0; i--)
+		array_wr32(IGC_MTA, i, hw->mac.mta_shadow[i]);
+	wrfl();
+}