ixgbe: Add optional DCA infrastructure

82598 cards and up support DCA, which enables the chipset to warm
up the caches for upcoming payload data. This code makes the
driver plug into the CONFIG_DCA infrastructure that was merged
earlier.
Signed-off-by: Jeb Cramer <cramerj@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/ixgbe/ixgbe.h

@@ -36,6 +36,9 @@
 #include "ixgbe_type.h"
 #include "ixgbe_common.h"
 
+#ifdef CONFIG_DCA
+#include <linux/dca.h>
+#endif
 
 #define IXGBE_ERR(args...) printk(KERN_ERR "ixgbe: " args)
 
@@ -142,6 +145,11 @@ struct ixgbe_ring {
 	u16 reg_idx; /* holds the special value that gets the hardware register
 		      * offset associated with this ring, which is different
 		      * for DCE and RSS modes */
+
+#ifdef CONFIG_DCA
+	/* cpu for tx queue */
+	int cpu;
+#endif
 	struct ixgbe_queue_stats stats;
 	u8 v_idx; /* maps directly to the index for this ring in the hardware
 		   * vector array, can also be used for finding the bit in EICR
@@ -261,6 +269,7 @@ struct ixgbe_adapter {
 #define IXGBE_FLAG_IMIR_ENABLED                 (u32)(1 << 5)
 #define IXGBE_FLAG_RSS_ENABLED                  (u32)(1 << 6)
 #define IXGBE_FLAG_VMDQ_ENABLED                 (u32)(1 << 7)
+#define IXGBE_FLAG_DCA_ENABLED                  (u32)(1 << 8)
 
 	/* OS defined structs */
 	struct net_device *netdev;

drivers/net/ixgbe/ixgbe_main.c

@@ -80,6 +80,16 @@ static struct pci_device_id ixgbe_pci_tbl[] = {
 };
 MODULE_DEVICE_TABLE(pci, ixgbe_pci_tbl);
 
+#ifdef CONFIG_DCA
+static int ixgbe_notify_dca(struct notifier_block *, unsigned long event,
+			    void *p);
+static struct notifier_block dca_notifier = {
+	.notifier_call = ixgbe_notify_dca,
+	.next          = NULL,
+	.priority      = 0
+};
+#endif
+
 MODULE_AUTHOR("Intel Corporation, <linux.nics@intel.com>");
 MODULE_DESCRIPTION("Intel(R) 10 Gigabit PCI Express Network Driver");
 MODULE_LICENSE("GPL");
@@ -290,6 +300,91 @@ static bool ixgbe_clean_tx_irq(struct ixgbe_adapter *adapter,
 	return cleaned;
 }
 
+#ifdef CONFIG_DCA
+static void ixgbe_update_rx_dca(struct ixgbe_adapter *adapter,
+				struct ixgbe_ring *rxr)
+{
+	u32 rxctrl;
+	int cpu = get_cpu();
+	int q = rxr - adapter->rx_ring;
+
+	if (rxr->cpu != cpu) {
+		rxctrl = IXGBE_READ_REG(&adapter->hw, IXGBE_DCA_RXCTRL(q));
+		rxctrl &= ~IXGBE_DCA_RXCTRL_CPUID_MASK;
+		rxctrl |= dca_get_tag(cpu);
+		rxctrl |= IXGBE_DCA_RXCTRL_DESC_DCA_EN;
+		rxctrl |= IXGBE_DCA_RXCTRL_HEAD_DCA_EN;
+		IXGBE_WRITE_REG(&adapter->hw, IXGBE_DCA_RXCTRL(q), rxctrl);
+		rxr->cpu = cpu;
+	}
+	put_cpu();
+}
+
+static void ixgbe_update_tx_dca(struct ixgbe_adapter *adapter,
+				struct ixgbe_ring *txr)
+{
+	u32 txctrl;
+	int cpu = get_cpu();
+	int q = txr - adapter->tx_ring;
+
+	if (txr->cpu != cpu) {
+		txctrl = IXGBE_READ_REG(&adapter->hw, IXGBE_DCA_TXCTRL(q));
+		txctrl &= ~IXGBE_DCA_TXCTRL_CPUID_MASK;
+		txctrl |= dca_get_tag(cpu);
+		txctrl |= IXGBE_DCA_TXCTRL_DESC_DCA_EN;
+		IXGBE_WRITE_REG(&adapter->hw, IXGBE_DCA_TXCTRL(q), txctrl);
+		txr->cpu = cpu;
+	}
+	put_cpu();
+}
+
+static void ixgbe_setup_dca(struct ixgbe_adapter *adapter)
+{
+	int i;
+
+	if (!(adapter->flags & IXGBE_FLAG_DCA_ENABLED))
+		return;
+
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		adapter->tx_ring[i].cpu = -1;
+		ixgbe_update_tx_dca(adapter, &adapter->tx_ring[i]);
+	}
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		adapter->rx_ring[i].cpu = -1;
+		ixgbe_update_rx_dca(adapter, &adapter->rx_ring[i]);
+	}
+}
+
+static int __ixgbe_notify_dca(struct device *dev, void *data)
+{
+	struct net_device *netdev = dev_get_drvdata(dev);
+	struct ixgbe_adapter *adapter = netdev_priv(netdev);
+	unsigned long event = *(unsigned long *)data;
+
+	switch (event) {
+	case DCA_PROVIDER_ADD:
+		adapter->flags |= IXGBE_FLAG_DCA_ENABLED;
+		/* Always use CB2 mode, difference is masked
+		 * in the CB driver. */
+		IXGBE_WRITE_REG(&adapter->hw, IXGBE_DCA_CTRL, 2);
+		if (dca_add_requester(dev) == IXGBE_SUCCESS) {
+			ixgbe_setup_dca(adapter);
+			break;
+		}
+		/* Fall Through since DCA is disabled. */
+	case DCA_PROVIDER_REMOVE:
+		if (adapter->flags & IXGBE_FLAG_DCA_ENABLED) {
+			dca_remove_requester(dev);
+			adapter->flags &= ~IXGBE_FLAG_DCA_ENABLED;
+			IXGBE_WRITE_REG(&adapter->hw, IXGBE_DCA_CTRL, 1);
+		}
+		break;
+	}
+
+	return IXGBE_SUCCESS;
+}
+
+#endif /* CONFIG_DCA */
 /**
  * ixgbe_receive_skb - Send a completed packet up the stack
  * @adapter: board private structure
@@ -811,6 +906,10 @@ static irqreturn_t ixgbe_msix_clean_tx(int irq, void *data)
 	r_idx = find_first_bit(q_vector->txr_idx, adapter->num_tx_queues);
 	for (i = 0; i < q_vector->txr_count; i++) {
 		txr = &(adapter->tx_ring[r_idx]);
+#ifdef CONFIG_DCA
+		if (adapter->flags & IXGBE_FLAG_DCA_ENABLED)
+			ixgbe_update_tx_dca(adapter, txr);
+#endif
 		txr->total_bytes = 0;
 		txr->total_packets = 0;
 		ixgbe_clean_tx_irq(adapter, txr);
@@ -872,6 +971,10 @@ static int ixgbe_clean_rxonly(struct napi_struct *napi, int budget)
 
 	r_idx = find_first_bit(q_vector->rxr_idx, adapter->num_rx_queues);
 	rxr = &(adapter->rx_ring[r_idx]);
+#ifdef CONFIG_DCA
+	if (adapter->flags & IXGBE_FLAG_DCA_ENABLED)
+		ixgbe_update_rx_dca(adapter, rxr);
+#endif
 
 	ixgbe_clean_rx_irq(adapter, rxr, &work_done, budget);
 
@@ -1924,6 +2027,13 @@ static int ixgbe_poll(struct napi_struct *napi, int budget)
 	struct ixgbe_adapter *adapter = q_vector->adapter;
 	int tx_cleaned = 0, work_done = 0;
 
+#ifdef CONFIG_DCA
+	if (adapter->flags & IXGBE_FLAG_DCA_ENABLED) {
+		ixgbe_update_tx_dca(adapter, adapter->tx_ring);
+		ixgbe_update_rx_dca(adapter, adapter->rx_ring);
+	}
+#endif
+
 	tx_cleaned = ixgbe_clean_tx_irq(adapter, adapter->tx_ring);
 	ixgbe_clean_rx_irq(adapter, adapter->rx_ring, &work_done, budget);
 
@@ -3494,6 +3604,15 @@ static int __devinit ixgbe_probe(struct pci_dev *pdev,
 	if (err)
 		goto err_register;
 
+#ifdef CONFIG_DCA
+	if (dca_add_requester(&pdev->dev) == IXGBE_SUCCESS) {
+		adapter->flags |= IXGBE_FLAG_DCA_ENABLED;
+		/* always use CB2 mode, difference is masked
+		 * in the CB driver */
+		IXGBE_WRITE_REG(hw, IXGBE_DCA_CTRL, 2);
+		ixgbe_setup_dca(adapter);
+	}
+#endif
 
 	dev_info(&pdev->dev, "Intel(R) 10 Gigabit Network Connection\n");
 	cards_found++;
@@ -3535,6 +3654,14 @@ static void __devexit ixgbe_remove(struct pci_dev *pdev)
 
 	flush_scheduled_work();
 
+#ifdef CONFIG_DCA
+	if (adapter->flags & IXGBE_FLAG_DCA_ENABLED) {
+		adapter->flags &= ~IXGBE_FLAG_DCA_ENABLED;
+		dca_remove_requester(&pdev->dev);
+		IXGBE_WRITE_REG(&adapter->hw, IXGBE_DCA_CTRL, 1);
+	}
+
+#endif
 	unregister_netdev(netdev);
 
 	ixgbe_reset_interrupt_capability(adapter);
@@ -3659,6 +3786,10 @@ static int __init ixgbe_init_module(void)
 
 	printk(KERN_INFO "%s: %s\n", ixgbe_driver_name, ixgbe_copyright);
 
+#ifdef CONFIG_DCA
+	dca_register_notify(&dca_notifier);
+
+#endif
 	ret = pci_register_driver(&ixgbe_driver);
 	return ret;
 }
@@ -3672,8 +3803,25 @@ module_init(ixgbe_init_module);
  **/
 static void __exit ixgbe_exit_module(void)
 {
+#ifdef CONFIG_DCA
+	dca_unregister_notify(&dca_notifier);
+#endif
 	pci_unregister_driver(&ixgbe_driver);
 }
+
+#ifdef CONFIG_DCA
+static int ixgbe_notify_dca(struct notifier_block *nb, unsigned long event,
+			    void *p)
+{
+	int ret_val;
+
+	ret_val = driver_for_each_device(&ixgbe_driver.driver, NULL, &event,
+					 __ixgbe_notify_dca);
+
+	return ret_val ? NOTIFY_BAD : NOTIFY_DONE;
+}
+#endif /* CONFIG_DCA */
+
 module_exit(ixgbe_exit_module);
 
 /* ixgbe_main.c */