igc: Refactor ethertype filtering code

The whole ethertype filtering code is implemented in igc_ethtool.c and
mixes logic from ethtool and core parts. This patch refactors it so core
logic is moved to igc_main.c, aligning the ethertype filtering code
organization with the rest of the filtering code from the driver (MAC
address and VLAN priority).

Besides moving code to igc_main.c, this patch also does some minor
improvements to the code. Below are some highlights.

In case all filters are already in use and the user tries to add another
filter, we return -ENOSPC instead of -EINVAL so a more meaningful error
code is provided. This also aligns with the behavior implemented in MAC
address filtering code.

With this code refactoring, 'etype_bitmap' array in struct igc_adapter
and 'etype_reg_index' in struct igc_nfc_filter are not needed anymore
and are removed.

Log messages are added to help debugging the ethertype filtering code.

Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 93 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 7e59c0393dbc..0df5617eb9d0 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -2366,6 +2366,99 @@ void igc_del_vlan_prio_filter(struct igc_adapter *adapter, int prio)
 		   prio);
 }
 
+static int igc_get_avail_etype_filter_slot(struct igc_adapter *adapter)
+{
+	struct igc_hw *hw = &adapter->hw;
+	int i;
+
+	for (i = 0; i < MAX_ETYPE_FILTER; i++) {
+		u32 etqf = rd32(IGC_ETQF(i));
+
+		if (!(etqf & IGC_ETQF_FILTER_ENABLE))
+			return i;
+	}
+
+	return -1;
+}
+
+/**
+ * igc_add_etype_filter() - Add ethertype filter
+ * @adapter: Pointer to adapter where the filter should be added
+ * @etype: Ethertype value
+ * @queue: If non-negative, queue assignment feature is enabled and frames
+ *         matching the filter are enqueued onto 'queue'. Otherwise, queue
+ *         assignment is disabled.
+ *
+ * Return: 0 in case of success, negative errno code otherwise.
+ */
+int igc_add_etype_filter(struct igc_adapter *adapter, u16 etype, int queue)
+{
+	struct igc_hw *hw = &adapter->hw;
+	int index;
+	u32 etqf;
+
+	index = igc_get_avail_etype_filter_slot(adapter);
+	if (index < 0)
+		return -ENOSPC;
+
+	etqf = rd32(IGC_ETQF(index));
+
+	etqf &= ~IGC_ETQF_ETYPE_MASK;
+	etqf |= etype;
+
+	if (queue >= 0) {
+		etqf &= ~IGC_ETQF_QUEUE_MASK;
+		etqf |= (queue << IGC_ETQF_QUEUE_SHIFT);
+		etqf |= IGC_ETQF_QUEUE_ENABLE;
+	}
+
+	etqf |= IGC_ETQF_FILTER_ENABLE;
+
+	wr32(IGC_ETQF(index), etqf);
+
+	netdev_dbg(adapter->netdev, "Add ethertype filter: etype %04x queue %d\n",
+		   etype, queue);
+	return 0;
+}
+
+static int igc_find_etype_filter(struct igc_adapter *adapter, u16 etype)
+{
+	struct igc_hw *hw = &adapter->hw;
+	int i;
+
+	for (i = 0; i < MAX_ETYPE_FILTER; i++) {
+		u32 etqf = rd32(IGC_ETQF(i));
+
+		if ((etqf & IGC_ETQF_ETYPE_MASK) == etype)
+			return i;
+	}
+
+	return -1;
+}
+
+/**
+ * igc_del_etype_filter() - Delete ethertype filter
+ * @adapter: Pointer to adapter where the filter should be deleted from
+ * @etype: Ethertype value
+ *
+ * Return: 0 in case of success, negative errno code otherwise.
+ */
+int igc_del_etype_filter(struct igc_adapter *adapter, u16 etype)
+{
+	struct igc_hw *hw = &adapter->hw;
+	int index;
+
+	index = igc_find_etype_filter(adapter, etype);
+	if (index < 0)
+		return -ENOENT;
+
+	wr32(IGC_ETQF(index), 0);
+
+	netdev_dbg(adapter->netdev, "Delete ethertype filter: etype %04x\n",
+		   etype);
+	return 0;
+}
+
 static int igc_uc_sync(struct net_device *netdev, const unsigned char *addr)
 {
 	struct igc_adapter *adapter = netdev_priv(netdev);