igb: re-order queues to support cleaner use of ivar on 82576

The 82576 adapter orders the queues in pairs when virtualization is in use.
The queue ordering previously conflicted with the ordering when sr-iov was
enabled.  This new ordering allows a PF to allocate 2 queues without using
any VF resources.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/igb/igb.h

@@ -159,7 +159,8 @@ struct igb_ring {
 	u16 itr_register;
 	u16 cpu;
 
-	int queue_index;
+	u16 queue_index;
+	u16 reg_idx;
 	unsigned int total_bytes;
 	unsigned int total_packets;
 

drivers/net/igb/igb_main.c

@@ -231,6 +231,40 @@ static void __exit igb_exit_module(void)
 
 module_exit(igb_exit_module);
 
+#define Q_IDX_82576(i) (((i & 0x1) << 3) + (i >> 1))
+/**
+ * igb_cache_ring_register - Descriptor ring to register mapping
+ * @adapter: board private structure to initialize
+ *
+ * Once we know the feature-set enabled for the device, we'll cache
+ * the register offset the descriptor ring is assigned to.
+ **/
+static void igb_cache_ring_register(struct igb_adapter *adapter)
+{
+	int i;
+
+	switch (adapter->hw.mac.type) {
+	case e1000_82576:
+		/* The queues are allocated for virtualization such that VF 0
+		 * is allocated queues 0 and 8, VF 1 queues 1 and 9, etc.
+		 * In order to avoid collision we start at the first free queue
+		 * and continue consuming queues in the same sequence
+		 */
+		for (i = 0; i < adapter->num_rx_queues; i++)
+			adapter->rx_ring[i].reg_idx = Q_IDX_82576(i);
+		for (i = 0; i < adapter->num_tx_queues; i++)
+			adapter->tx_ring[i].reg_idx = Q_IDX_82576(i);
+		break;
+	case e1000_82575:
+	default:
+		for (i = 0; i < adapter->num_rx_queues; i++)
+			adapter->rx_ring[i].reg_idx = i;
+		for (i = 0; i < adapter->num_tx_queues; i++)
+			adapter->tx_ring[i].reg_idx = i;
+		break;
+	}
+}
+
 /**
  * igb_alloc_queues - Allocate memory for all rings
  * @adapter: board private structure to initialize
@@ -272,6 +306,8 @@ static int igb_alloc_queues(struct igb_adapter *adapter)
 		/* set a default napi handler for each rx_ring */
 		netif_napi_add(adapter->netdev, &ring->napi, igb_poll, 64);
 	}
+
+	igb_cache_ring_register(adapter);
 	return 0;
 }
 
@@ -312,36 +348,36 @@ static void igb_assign_vector(struct igb_adapter *adapter, int rx_queue,
 		array_wr32(E1000_MSIXBM(0), msix_vector, msixbm);
 		break;
 	case e1000_82576:
-		/* The 82576 uses a table-based method for assigning vectors.
+		/* 82576 uses a table-based method for assigning vectors.
 		   Each queue has a single entry in the table to which we write
 		   a vector number along with a "valid" bit.  Sadly, the layout
 		   of the table is somewhat counterintuitive. */
 		if (rx_queue > IGB_N0_QUEUE) {
-			index = (rx_queue & 0x7);
+			index = (rx_queue >> 1);
 			ivar = array_rd32(E1000_IVAR0, index);
-			if (rx_queue < 8) {
-				/* vector goes into low byte of register */
-				ivar = ivar & 0xFFFFFF00;
-				ivar |= msix_vector | E1000_IVAR_VALID;
-			} else {
+			if (rx_queue & 0x1) {
 				/* vector goes into third byte of register */
 				ivar = ivar & 0xFF00FFFF;
 				ivar |= (msix_vector | E1000_IVAR_VALID) << 16;
+			} else {
+				/* vector goes into low byte of register */
+				ivar = ivar & 0xFFFFFF00;
+				ivar |= msix_vector | E1000_IVAR_VALID;
 			}
 			adapter->rx_ring[rx_queue].eims_value= 1 << msix_vector;
 			array_wr32(E1000_IVAR0, index, ivar);
 		}
 		if (tx_queue > IGB_N0_QUEUE) {
-			index = (tx_queue & 0x7);
+			index = (tx_queue >> 1);
 			ivar = array_rd32(E1000_IVAR0, index);
-			if (tx_queue < 8) {
-				/* vector goes into second byte of register */
-				ivar = ivar & 0xFFFF00FF;
-				ivar |= (msix_vector | E1000_IVAR_VALID) << 8;
-			} else {
+			if (tx_queue & 0x1) {
 				/* vector goes into high byte of register */
 				ivar = ivar & 0x00FFFFFF;
 				ivar |= (msix_vector | E1000_IVAR_VALID) << 24;
+			} else {
+				/* vector goes into second byte of register */
+				ivar = ivar & 0xFFFF00FF;
+				ivar |= (msix_vector | E1000_IVAR_VALID) << 8;
 			}
 			adapter->tx_ring[tx_queue].eims_value= 1 << msix_vector;
 			array_wr32(E1000_IVAR0, index, ivar);
@@ -1638,33 +1674,33 @@ static void igb_configure_tx(struct igb_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 	u32 tctl;
 	u32 txdctl, txctrl;
-	int i;
+	int i, j;
 
 	for (i = 0; i < adapter->num_tx_queues; i++) {
 		struct igb_ring *ring = &(adapter->tx_ring[i]);
-
-		wr32(E1000_TDLEN(i),
+		j = ring->reg_idx;
+		wr32(E1000_TDLEN(j),
 				ring->count * sizeof(struct e1000_tx_desc));
 		tdba = ring->dma;
-		wr32(E1000_TDBAL(i),
+		wr32(E1000_TDBAL(j),
 				tdba & 0x00000000ffffffffULL);
-		wr32(E1000_TDBAH(i), tdba >> 32);
+		wr32(E1000_TDBAH(j), tdba >> 32);
 
-		ring->head = E1000_TDH(i);
-		ring->tail = E1000_TDT(i);
+		ring->head = E1000_TDH(j);
+		ring->tail = E1000_TDT(j);
 		writel(0, hw->hw_addr + ring->tail);
 		writel(0, hw->hw_addr + ring->head);
-		txdctl = rd32(E1000_TXDCTL(i));
+		txdctl = rd32(E1000_TXDCTL(j));
 		txdctl |= E1000_TXDCTL_QUEUE_ENABLE;
-		wr32(E1000_TXDCTL(i), txdctl);
+		wr32(E1000_TXDCTL(j), txdctl);
 
 		/* Turn off Relaxed Ordering on head write-backs.  The
 		 * writebacks MUST be delivered in order or it will
 		 * completely screw up our bookeeping.
 		 */
-		txctrl = rd32(E1000_DCA_TXCTRL(i));
+		txctrl = rd32(E1000_DCA_TXCTRL(j));
 		txctrl &= ~E1000_DCA_TXCTRL_TX_WB_RO_EN;
-		wr32(E1000_DCA_TXCTRL(i), txctrl);
+		wr32(E1000_DCA_TXCTRL(j), txctrl);
 	}
 
 
@@ -1781,7 +1817,7 @@ static void igb_setup_rctl(struct igb_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 	u32 rctl;
 	u32 srrctl = 0;
-	int i;
+	int i, j;
 
 	rctl = rd32(E1000_RCTL);
 
@@ -1839,8 +1875,10 @@ static void igb_setup_rctl(struct igb_adapter *adapter)
 		srrctl |= E1000_SRRCTL_DESCTYPE_ADV_ONEBUF;
 	}
 
-	for (i = 0; i < adapter->num_rx_queues; i++)
-		wr32(E1000_SRRCTL(i), srrctl);
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		j = adapter->rx_ring[i].reg_idx;
+		wr32(E1000_SRRCTL(j), srrctl);
+	}
 
 	wr32(E1000_RCTL, rctl);
 }
@@ -1857,7 +1895,7 @@ static void igb_configure_rx(struct igb_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 	u32 rctl, rxcsum;
 	u32 rxdctl;
-	int i;
+	int i, j;
 
 	/* disable receives while setting up the descriptors */
 	rctl = rd32(E1000_RCTL);
@@ -1872,25 +1910,26 @@ static void igb_configure_rx(struct igb_adapter *adapter)
 	 * the Base and Length of the Rx Descriptor Ring */
 	for (i = 0; i < adapter->num_rx_queues; i++) {
 		struct igb_ring *ring = &(adapter->rx_ring[i]);
+		j = ring->reg_idx;
 		rdba = ring->dma;
-		wr32(E1000_RDBAL(i),
+		wr32(E1000_RDBAL(j),
 				rdba & 0x00000000ffffffffULL);
-		wr32(E1000_RDBAH(i), rdba >> 32);
-		wr32(E1000_RDLEN(i),
+		wr32(E1000_RDBAH(j), rdba >> 32);
+		wr32(E1000_RDLEN(j),
 			       ring->count * sizeof(union e1000_adv_rx_desc));
 
-		ring->head = E1000_RDH(i);
-		ring->tail = E1000_RDT(i);
+		ring->head = E1000_RDH(j);
+		ring->tail = E1000_RDT(j);
 		writel(0, hw->hw_addr + ring->tail);
 		writel(0, hw->hw_addr + ring->head);
 
-		rxdctl = rd32(E1000_RXDCTL(i));
+		rxdctl = rd32(E1000_RXDCTL(j));
 		rxdctl |= E1000_RXDCTL_QUEUE_ENABLE;
 		rxdctl &= 0xFFF00000;
 		rxdctl |= IGB_RX_PTHRESH;
 		rxdctl |= IGB_RX_HTHRESH << 8;
 		rxdctl |= IGB_RX_WTHRESH << 16;
-		wr32(E1000_RXDCTL(i), rxdctl);
+		wr32(E1000_RXDCTL(j), rxdctl);
 #ifdef CONFIG_IGB_LRO
 		/* Intitial LRO Settings */
 		ring->lro_mgr.max_aggr = MAX_LRO_AGGR;
@@ -1920,7 +1959,7 @@ static void igb_configure_rx(struct igb_adapter *adapter)
 			shift = 6;
 		for (j = 0; j < (32 * 4); j++) {
 			reta.bytes[j & 3] =
-				(j % adapter->num_rx_queues) << shift;
+				adapter->rx_ring[(j % adapter->num_rx_queues)].reg_idx << shift;
 			if ((j & 3) == 3)
 				writel(reta.dword,
 				       hw->hw_addr + E1000_RETA(0) + (j & ~3));
@@ -3365,7 +3404,7 @@ static void igb_update_rx_dca(struct igb_ring *rx_ring)
 	struct igb_adapter *adapter = rx_ring->adapter;
 	struct e1000_hw *hw = &adapter->hw;
 	int cpu = get_cpu();
-	int q = rx_ring - adapter->rx_ring;
+	int q = rx_ring->reg_idx;
 
 	if (rx_ring->cpu != cpu) {
 		dca_rxctrl = rd32(E1000_DCA_RXCTRL(q));
@@ -3392,7 +3431,7 @@ static void igb_update_tx_dca(struct igb_ring *tx_ring)
 	struct igb_adapter *adapter = tx_ring->adapter;
 	struct e1000_hw *hw = &adapter->hw;
 	int cpu = get_cpu();
-	int q = tx_ring - adapter->tx_ring;
+	int q = tx_ring->reg_idx;
 
 	if (tx_ring->cpu != cpu) {
 		dca_txctrl = rd32(E1000_DCA_TXCTRL(q));