[dpdk-dev] [PATCH] drivers/i40e: fix link update no wait

[Fan Zhang]

Fixes: 263333bbb7a9 ("i40e: fix link status timeout")

In i40e_dev_link_update() the driver obtains the link status
info via admin queue command despite of "no_wait" flag. This
requires relatively long time and may be a problem to some
application such as ovs-dpdk
(https://bugzilla.redhat.com/show_bug.cgi?id=1551761).

This patch aims to fix the problem by using a different
approach of obtaining link status for i40e NIC without waiting.
Instead of getting the link status via admin queue command,
this patch reads the link status registers to accelerate the
procedure.

Signed-off-by: Fan Zhang <roy.fan.zhang at intel.com>
Signed-off-by: Andrey Chilikin <andrey.chilikin at intel.com>
---
 drivers/net/i40e/i40e_ethdev.c | 128 ++++++++++++++++++++++++++++++-----------
 1 file changed, 95 insertions(+), 33 deletions(-)

diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
index 508b4171c..968249ed1 100644
--- a/drivers/net/i40e/i40e_ethdev.c
+++ b/drivers/net/i40e/i40e_ethdev.c
@@ -2437,77 +2437,139 @@ i40e_dev_set_link_down(struct rte_eth_dev *dev)
 	return i40e_phy_conf_link(hw, abilities, speed, false);
 }
 
-int
-i40e_dev_link_update(struct rte_eth_dev *dev,
-		     int wait_to_complete)
+static __rte_always_inline void
+update_link_no_wait(struct i40e_hw *hw, struct rte_eth_link *link)
+{
+/* Link status registers and values*/
+#define I40E_PRTMAC_LINKSTA		0x001E2420
+#define I40E_REG_LINK_UP		0x40000080
+#define I40E_PRTMAC_MACC		0x001E24E0
+#define I40E_REG_MACC_25GB		0x00020000
+#define I40E_REG_SPEED_MASK		0x38000000
+#define I40E_REG_SPEED_100MB		0x00000000
+#define I40E_REG_SPEED_1GB		0x08000000
+#define I40E_REG_SPEED_10GB		0x10000000
+#define I40E_REG_SPEED_20GB		0x20000000
+#define I40E_REG_SPEED_25_40GB		0x18000000
+	uint32_t link_speed;
+	uint32_t reg_val;
+
+	reg_val = I40E_READ_REG(hw, I40E_PRTMAC_LINKSTA);
+	link_speed = reg_val & I40E_REG_SPEED_MASK;
+	reg_val &= I40E_REG_LINK_UP;
+	link->link_status = (reg_val == I40E_REG_LINK_UP) ? 1 : 0;
+
+	if (unlikely(link->link_status != 0))
+		return;
+
+	/* Parse the link status */
+	switch (link_speed) {
+	case I40E_REG_SPEED_100MB:
+		link->link_speed = ETH_SPEED_NUM_100M;
+		break;
+	case I40E_REG_SPEED_1GB:
+		link->link_speed = ETH_SPEED_NUM_1G;
+		break;
+	case I40E_REG_SPEED_10GB:
+		link->link_speed = ETH_SPEED_NUM_10G;
+		break;
+	case I40E_REG_SPEED_20GB:
+		link->link_speed = ETH_SPEED_NUM_20G;
+		break;
+	case I40E_REG_SPEED_25_40GB:
+		reg_val = I40E_READ_REG(hw, I40E_PRTMAC_MACC);
+
+		if (reg_val & I40E_REG_MACC_25GB)
+			link->link_speed = ETH_SPEED_NUM_25G;
+		else
+			link->link_speed = ETH_SPEED_NUM_40G;
+
+		break;
+	default:
+		PMD_DRV_LOG(ERR, "Unknown link speed info %u", link_speed);
+		break;
+	}
+}
+
+static __rte_always_inline void
+update_link_wait(struct i40e_hw *hw, struct rte_eth_link *link,
+	bool enable_lse)
 {
-#define CHECK_INTERVAL 100  /* 100ms */
-#define MAX_REPEAT_TIME 10  /* 1s (10 * 100ms) in total */
-	struct i40e_hw *hw = I40E_DEV_PRIVATE_TO_HW(dev->data->dev_private);
+#define CHECK_INTERVAL             100  /* 100ms */
+#define MAX_REPEAT_TIME            10  /* 1s (10 * 100ms) in total */
+	uint32_t rep_cnt = MAX_REPEAT_TIME;
 	struct i40e_link_status link_status;
-	struct rte_eth_link link, old;
 	int status;
-	unsigned rep_cnt = MAX_REPEAT_TIME;
-	bool enable_lse = dev->data->dev_conf.intr_conf.lsc ? true : false;
 
-	memset(&link, 0, sizeof(link));
-	memset(&old, 0, sizeof(old));
 	memset(&link_status, 0, sizeof(link_status));
-	rte_i40e_dev_atomic_read_link_status(dev, &old);
 
 	do {
 		/* Get link status information from hardware */
 		status = i40e_aq_get_link_info(hw, enable_lse,
 						&link_status, NULL);
-		if (status != I40E_SUCCESS) {
-			link.link_speed = ETH_SPEED_NUM_100M;
-			link.link_duplex = ETH_LINK_FULL_DUPLEX;
+		if (unlikely(status != I40E_SUCCESS)) {
+			link->link_speed = ETH_SPEED_NUM_100M;
+			link->link_duplex = ETH_LINK_FULL_DUPLEX;
 			PMD_DRV_LOG(ERR, "Failed to get link info");
-			goto out;
+			return;
 		}
 
-		link.link_status = link_status.link_info & I40E_AQ_LINK_UP;
-		if (!wait_to_complete || link.link_status)
-			break;
+		link->link_status = link_status.link_info & I40E_AQ_LINK_UP;
+		if (unlikely(link->link_status != 0))
+			return;
 
 		rte_delay_ms(CHECK_INTERVAL);
 	} while (--rep_cnt);
 
-	if (!link.link_status)
-		goto out;
-
-	/* i40e uses full duplex only */
-	link.link_duplex = ETH_LINK_FULL_DUPLEX;
-
 	/* Parse the link status */
 	switch (link_status.link_speed) {
 	case I40E_LINK_SPEED_100MB:
-		link.link_speed = ETH_SPEED_NUM_100M;
+		link->link_speed = ETH_SPEED_NUM_100M;
 		break;
 	case I40E_LINK_SPEED_1GB:
-		link.link_speed = ETH_SPEED_NUM_1G;
+		link->link_speed = ETH_SPEED_NUM_1G;
 		break;
 	case I40E_LINK_SPEED_10GB:
-		link.link_speed = ETH_SPEED_NUM_10G;
+		link->link_speed = ETH_SPEED_NUM_10G;
 		break;
 	case I40E_LINK_SPEED_20GB:
-		link.link_speed = ETH_SPEED_NUM_20G;
+		link->link_speed = ETH_SPEED_NUM_20G;
 		break;
 	case I40E_LINK_SPEED_25GB:
-		link.link_speed = ETH_SPEED_NUM_25G;
+		link->link_speed = ETH_SPEED_NUM_25G;
 		break;
 	case I40E_LINK_SPEED_40GB:
-		link.link_speed = ETH_SPEED_NUM_40G;
+		link->link_speed = ETH_SPEED_NUM_40G;
 		break;
 	default:
-		link.link_speed = ETH_SPEED_NUM_100M;
+		link->link_speed = ETH_SPEED_NUM_100M;
 		break;
 	}
+}
+
+int
+i40e_dev_link_update(struct rte_eth_dev *dev,
+		     int wait_to_complete)
+{
+	struct i40e_hw *hw = I40E_DEV_PRIVATE_TO_HW(dev->data->dev_private);
+	struct rte_eth_link link, old;
+	bool enable_lse = dev->data->dev_conf.intr_conf.lsc ? true : false;
 
+	memset(&link, 0, sizeof(link));
+	memset(&old, 0, sizeof(old));
+
+	rte_i40e_dev_atomic_read_link_status(dev, &old);
+
+	/* i40e uses full duplex only */
+	link.link_duplex = ETH_LINK_FULL_DUPLEX;
 	link.link_autoneg = !(dev->data->dev_conf.link_speeds &
 			ETH_LINK_SPEED_FIXED);
 
-out:
+	if (!wait_to_complete)
+		update_link_no_wait(hw, &link);
+	else
+		update_link_wait(hw, &link, enable_lse);
+
 	rte_i40e_dev_atomic_write_link_status(dev, &link);
 	if (link.link_status == old.link_status)
 		return -1;
-- 
2.13.6