[PATCH net-next] cxgb4vf: Forcefully link up virtual interfaces

[Ganesh Goudar <ganeshgr@chelsio.com>]

From: Arjun Vynipadath <arjun@chelsio.com>

The Virtual Interfaces are connected to an internal switch on the chip
which allows VIs attached to the same port to talk to each other even
when the port link is down.  As a result, we generally want to always
report a VI's link as being "up".

Based on the original work by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Arjun Vynipadath <arjun@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
---
 .../net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c    | 26 ++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
index b7e79e6..7fe8763 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
@@ -92,6 +92,18 @@ module_param(msi, int, 0644);
 MODULE_PARM_DESC(msi, "whether to use MSI-X or MSI");
 
 /*
+ * Logic controls.
+ * ===============
+ */
+
+/* The Virtual Interfaces are connected to an internal switch on the chip
+ * which allows VIs attached to the same port to talk to each other even when
+ * the port link is down.  As a result, we generally want to always report a
+ * VI's link as being "up".
+ */
+#define force_link_up 1
+
+/*
  * Fundamental constants.
  * ======================
  */
@@ -155,7 +167,8 @@ void t4vf_os_link_changed(struct adapter *adapter, int pidx, int link_ok)
 		const char *fc;
 		const struct port_info *pi = netdev_priv(dev);
 
-		netif_carrier_on(dev);
+		if (!force_link_up)
+			netif_carrier_on(dev);
 
 		switch (pi->link_cfg.speed) {
 		case 100:
@@ -202,7 +215,9 @@ void t4vf_os_link_changed(struct adapter *adapter, int pidx, int link_ok)
 
 		netdev_info(dev, "link up, %s, full-duplex, %s PAUSE\n", s, fc);
 	} else {
-		netif_carrier_off(dev);
+		if (!force_link_up)
+			netif_carrier_off(dev);
+
 		netdev_info(dev, "link down\n");
 	}
 }
@@ -278,6 +293,13 @@ static int link_start(struct net_device *dev)
 	 */
 	if (ret == 0)
 		ret = t4vf_enable_vi(pi->adapter, pi->viid, true, true);
+
+	/* If we didn't experience any error and we're always reporting the
+	 * link as being "up", tell the OS that the link is up.
+	 */
+	if (ret == 0 && force_link_up)
+		netif_carrier_on(dev);
+
 	return ret;
 }
 
-- 
2.1.0