[PATCH v2 iwl-next 1/3] igc: prepare for RSS key get/set support

[Kohei Enju <kohei@enjuk.jp>]

Store the RSS key inside struct igc_adapter and introduce the
igc_write_rss_key() helper function. This allows the driver to program
the RSSRK registers using a persistent RSS key, instead of using a
stack-local buffer in igc_setup_mrqc().

This is a preparation patch for adding RSS key get/set support in
subsequent changes, and no functional change is intended in this patch.

Signed-off-by: Kohei Enju <kohei@enjuk.jp>
---
 drivers/net/ethernet/intel/igc/igc.h         |  3 +++
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 20 ++++++++++++++++++++
 drivers/net/ethernet/intel/igc/igc_main.c    |  8 ++++----
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index a427f05814c1..dd159397d191 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -30,6 +30,7 @@ void igc_ethtool_set_ops(struct net_device *);
 
 #define MAX_ETYPE_FILTER		8
 #define IGC_RETA_SIZE			128
+#define IGC_RSS_KEY_SIZE		40
 
 /* SDP support */
 #define IGC_N_EXTTS	2
@@ -302,6 +303,7 @@ struct igc_adapter {
 	unsigned int nfc_rule_count;
 
 	u8 rss_indir_tbl[IGC_RETA_SIZE];
+	u8 rss_key[IGC_RSS_KEY_SIZE];
 
 	unsigned long link_check_timeout;
 	struct igc_info ei;
@@ -360,6 +362,7 @@ unsigned int igc_get_max_rss_queues(struct igc_adapter *adapter);
 void igc_set_flag_queue_pairs(struct igc_adapter *adapter,
 			      const u32 max_rss_queues);
 int igc_reinit_queues(struct igc_adapter *adapter);
+void igc_write_rss_key(struct igc_adapter *adapter);
 void igc_write_rss_indir_tbl(struct igc_adapter *adapter);
 bool igc_has_link(struct igc_adapter *adapter);
 void igc_reset(struct igc_adapter *adapter);
diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index 3172cdbca9cc..1b4075e7e8e6 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1460,6 +1460,26 @@ static int igc_ethtool_set_rxnfc(struct net_device *dev,
 	}
 }
 
+/**
+ * igc_write_rss_key - Program the RSS key into device registers
+ * @adapter: board private structure
+ *
+ * Write the RSS key stored in adapter->rss_key to the IGC_RSSRK registers.
+ * Each 32-bit chunk of the key is read using get_unaligned_le32() and written
+ * to the appropriate register.
+ */
+void igc_write_rss_key(struct igc_adapter *adapter)
+{
+	struct igc_hw *hw = &adapter->hw;
+	u32 val;
+	int i;
+
+	for (i = 0; i < IGC_RSS_KEY_SIZE / 4; i++) {
+		val = get_unaligned_le32(&adapter->rss_key[i * 4]);
+		wr32(IGC_RSSRK(i), val);
+	}
+}
+
 void igc_write_rss_indir_tbl(struct igc_adapter *adapter)
 {
 	struct igc_hw *hw = &adapter->hw;
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 89a321a344d2..98410f9d7828 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -778,11 +778,8 @@ static void igc_setup_mrqc(struct igc_adapter *adapter)
 	struct igc_hw *hw = &adapter->hw;
 	u32 j, num_rx_queues;
 	u32 mrqc, rxcsum;
-	u32 rss_key[10];
 
-	netdev_rss_key_fill(rss_key, sizeof(rss_key));
-	for (j = 0; j < 10; j++)
-		wr32(IGC_RSSRK(j), rss_key[j]);
+	igc_write_rss_key(adapter);
 
 	num_rx_queues = adapter->rss_queues;
 
@@ -5046,6 +5043,9 @@ static int igc_sw_init(struct igc_adapter *adapter)
 
 	pci_read_config_word(pdev, PCI_COMMAND, &hw->bus.pci_cmd_word);
 
+	/* init RSS key */
+	netdev_rss_key_fill(adapter->rss_key, sizeof(adapter->rss_key));
+
 	/* set default ring sizes */
 	adapter->tx_ring_count = IGC_DEFAULT_TXD;
 	adapter->rx_ring_count = IGC_DEFAULT_RXD;
-- 
2.51.0