[RFC 04/10] virtio: add support for Link State interrupt

[Stephen Hemminger <stephen-OTpzqLSitTUnbdJkjeBofR2eb7JE58TQ@public.gmane.org>]

[-- Attachment #1: virtio-lsc.patch --]
[-- Type: text/plain, Size: 5874 bytes --]

Virtio has link state interrupt which can be used.

Signed-off-by: Stephen Hemminger <shemming-43mecJUBy8ZBDgjK7y7TUQ@public.gmane.org>


---
 lib/librte_pmd_virtio/virtio_ethdev.c |   78 ++++++++++++++++++++++++++--------
 lib/librte_pmd_virtio/virtio_pci.c    |   22 +++++++++
 lib/librte_pmd_virtio/virtio_pci.h    |    4 +
 3 files changed, 86 insertions(+), 18 deletions(-)

--- a/lib/librte_pmd_virtio/virtio_ethdev.c	2014-08-25 19:00:06.342530488 -0700
+++ b/lib/librte_pmd_virtio/virtio_ethdev.c	2014-08-25 19:00:06.342530488 -0700
@@ -757,6 +757,34 @@ static int virtio_resource_init(struct r
 #endif
 
 /*
+ * Process Virtio Config changed interrupt and call the callback
+ * if link state changed.
+ */
+static void
+virtio_interrupt_handler(__rte_unused struct rte_intr_handle *handle,
+			 void *param)
+{
+	struct rte_eth_dev *dev = param;
+	struct virtio_hw *hw =
+		VIRTIO_DEV_PRIVATE_TO_HW(dev->data->dev_private);
+	uint8_t isr;
+
+	/* Read interrupt status which clears interrupt */
+	isr = vtpci_isr(hw);
+	PMD_DRV_LOG(INFO, "interrupt status = %#x", isr);
+
+	if (rte_intr_enable(&dev->pci_dev->intr_handle) < 0)
+		PMD_DRV_LOG(ERR, "interrupt enable failed");
+
+	if (isr & VIRTIO_PCI_ISR_CONFIG) {
+		if (virtio_dev_link_update(dev, 0) == 0)
+			_rte_eth_dev_callback_process(dev,
+						      RTE_ETH_EVENT_INTR_LSC);
+	}
+
+}
+
+/*
  * This function is based on probe() function in virtio_pci.c
  * It returns 0 on success.
  */
@@ -886,6 +914,10 @@ eth_virtio_dev_init(__rte_unused struct
 	PMD_INIT_LOG(DEBUG, "port %d vendorID=0x%x deviceID=0x%x",
 			eth_dev->data->port_id, pci_dev->id.vendor_id,
 			pci_dev->id.device_id);
+
+	/* Setup interrupt callback  */
+	rte_intr_callback_register(&pci_dev->intr_handle,
+				   virtio_interrupt_handler, eth_dev);
 	return 0;
 }
 
@@ -893,7 +925,7 @@ static struct eth_driver rte_virtio_pmd
 	{
 		.name = "rte_virtio_pmd",
 		.id_table = pci_id_virtio_map,
-		.drv_flags = RTE_PCI_DRV_NEED_MAPPING,
+		.drv_flags = RTE_PCI_DRV_NEED_MAPPING | RTE_PCI_DRV_INTR_LSC,
 	},
 	.eth_dev_init = eth_virtio_dev_init,
 	.dev_private_size = sizeof(struct virtio_adapter),
@@ -933,6 +965,9 @@ static int
 virtio_dev_configure(struct rte_eth_dev *dev)
 {
 	const struct rte_eth_rxmode *rxmode = &dev->data->dev_conf.rxmode;
+	struct virtio_hw *hw =
+		VIRTIO_DEV_PRIVATE_TO_HW(dev->data->dev_private);
+	int ret;
 
 	PMD_INIT_LOG(DEBUG, "configure");
 
@@ -941,7 +976,11 @@ virtio_dev_configure(struct rte_eth_dev
 		return (-EINVAL);
 	}
 
-	return 0;
+	ret = vtpci_irq_config(hw, 0);
+	if (ret != 0)
+		PMD_DRV_LOG(ERR, "failed to set config vector");
+
+	return ret;
 }
 
 
@@ -949,7 +988,6 @@ static int
 virtio_dev_start(struct rte_eth_dev *dev)
 {
 	uint16_t nb_queues, i;
-	uint16_t status;
 	struct virtio_hw *hw =
 		VIRTIO_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 
@@ -964,18 +1002,22 @@ virtio_dev_start(struct rte_eth_dev *dev
 	/* Do final configuration before rx/tx engine starts */
 	virtio_dev_rxtx_start(dev);
 
-	/* Check VIRTIO_NET_F_STATUS for link status*/
-	if (vtpci_with_feature(hw, VIRTIO_NET_F_STATUS)) {
-		vtpci_read_dev_config(hw,
-				offsetof(struct virtio_net_config, status),
-				&status, sizeof(status));
-		if ((status & VIRTIO_NET_S_LINK_UP) == 0)
-			PMD_INIT_LOG(ERR, "Port: %d Link is DOWN",
-				     dev->data->port_id);
-		else
-			PMD_INIT_LOG(DEBUG, "Port: %d Link is UP",
-				     dev->data->port_id);
+	/* check if lsc interrupt feature is enabled */
+	if (dev->data->dev_conf.intr_conf.lsc) {
+		if (!vtpci_with_feature(hw, VIRTIO_NET_F_STATUS)) {
+			PMD_DRV_LOG(ERR, "link status not supported by host");
+			return -ENOTSUP;
+		}
+
+		if (rte_intr_enable(&dev->pci_dev->intr_handle) < 0) {
+			PMD_DRV_LOG(ERR, "interrupt enable failed");
+			return -EIO;
+		}
 	}
+
+	/* Initialize Link state */
+	virtio_dev_link_update(dev, 0);
+
 	vtpci_reinit_complete(hw);
 
 	/*Notify the backend
@@ -1057,6 +1099,7 @@ virtio_dev_stop(struct rte_eth_dev *dev)
 		VIRTIO_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 
 	/* reset the NIC */
+	vtpci_irq_config(hw, 0);
 	vtpci_reset(hw);
 	virtio_dev_free_mbufs(dev);
 }
@@ -1073,6 +1116,7 @@ virtio_dev_link_update(struct rte_eth_de
 	old = link;
 	link.link_duplex = FULL_DUPLEX;
 	link.link_speed  = SPEED_10G;
+
 	if (vtpci_with_feature(hw, VIRTIO_NET_F_STATUS)) {
 		PMD_INIT_LOG(DEBUG, "Get link status from hw");
 		vtpci_read_dev_config(hw,
@@ -1091,10 +1135,8 @@ virtio_dev_link_update(struct rte_eth_de
 		link.link_status = 1;   /* Link up */
 	}
 	virtio_dev_atomic_write_link_status(dev, &link);
-	if (old.link_status == link.link_status)
-		return -1;
-	/*changed*/
-	return 0;
+
+	return (old.link_status == link.link_status) ? -1 : 0;
 }
 
 static void
--- a/lib/librte_pmd_virtio/virtio_pci.c	2014-08-25 19:00:06.342530488 -0700
+++ b/lib/librte_pmd_virtio/virtio_pci.c	2014-08-25 19:00:06.342530488 -0700
@@ -127,3 +127,25 @@ vtpci_set_status(struct virtio_hw *hw, u
 
 	VIRTIO_WRITE_REG_1(hw, VIRTIO_PCI_STATUS, status);
 }
+
+uint8_t
+vtpci_isr(struct virtio_hw *hw)
+{
+
+	return VIRTIO_READ_REG_1(hw, VIRTIO_PCI_ISR);
+}
+
+
+/* Enable one vector (0) for Link State Intrerrupt */
+int
+vtpci_irq_config(struct virtio_hw *hw, uint16_t vec)
+{
+	VIRTIO_WRITE_REG_2(hw, VIRTIO_MSI_CONFIG_VECTOR, vec);
+	vec = VIRTIO_READ_REG_2(hw, VIRTIO_MSI_CONFIG_VECTOR);
+	if (vec == VIRTIO_MSI_NO_VECTOR) {
+		PMD_DRV_LOG(ERR, "failed to set config vector");
+		return -EBUSY;
+	}
+
+	return 0;
+}
--- a/lib/librte_pmd_virtio/virtio_pci.h	2014-08-25 19:00:06.342530488 -0700
+++ b/lib/librte_pmd_virtio/virtio_pci.h	2014-08-25 19:00:06.342530488 -0700
@@ -263,4 +263,8 @@ void vtpci_write_dev_config(struct virti
 
 void vtpci_read_dev_config(struct virtio_hw *, uint64_t, void *, int);
 
+uint8_t vtpci_isr(struct virtio_hw *);
+
+int vtpci_irq_config(struct virtio_hw *, uint16_t);
+
 #endif /* _VIRTIO_PCI_H_ */