i40e: Separate out DCB capability and enabled flags

Currently if the firmware reports DCB capability the driver enables
I40E_FLAG_DCB_ENABLED flag. When this flag is enabled the driver
inserts a tag when transmitting a packet from the port even if there
are no DCB traffic classes configured at the port.

This patch adds a new flag I40E_FLAG_DCB_CAPABLE that will be set
when the DCB capability is present and the existing flag
I40E_FLAG_DCB_ENABLED will be set only if there are more than one
traffic classes configured at the port.

Change-ID: I24ccbf53ef293db2eba80c8a9772acf729795bd5
Signed-off-by: Neerav Parikh <neerav.parikh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

3 files changed, 25 insertions, 10 deletions

diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
index fc1bd1094397..5a8bbaafe500 100644
--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -264,6 +264,7 @@ struct i40e_pf {
 #ifdef CONFIG_I40E_VXLAN
 #define I40E_FLAG_VXLAN_FILTER_SYNC            (u64)(1 << 27)
 #endif
+#define I40E_FLAG_DCB_CAPABLE                  (u64)(1 << 29)
 
         /* tracks features that get auto disabled by errors */
         u64 auto_disable_flags;
diff --git a/drivers/net/ethernet/intel/i40e/i40e_dcb_nl.c b/drivers/net/ethernet/intel/i40e/i40e_dcb_nl.c
index 871831a535d0..00bc0cdb3a03 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_dcb_nl.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_dcb_nl.c
@@ -302,8 +302,8 @@ void i40e_dcbnl_setup(struct i40e_vsi *vsi)
         struct net_device *dev = vsi->netdev;
         struct i40e_pf *pf = i40e_netdev_to_pf(dev);
 
-        /* DCB not enabled */
-        if (!(pf->flags & I40E_FLAG_DCB_ENABLED))
+        /* Not DCB capable */
+        if (!(pf->flags & I40E_FLAG_DCB_CAPABLE))
                 return;
 
         /* Do not setup DCB NL ops for MFP mode */
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 145cb9fc1516..676bebb97f6e 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -4130,7 +4130,11 @@ static int i40e_init_pf_dcb(struct i40e_pf *pf)
                         /* When status is not DISABLED then DCBX in FW */
                         pf->dcbx_cap = DCB_CAP_DCBX_LLD_MANAGED |
                                        DCB_CAP_DCBX_VER_IEEE;
-                        pf->flags |= I40E_FLAG_DCB_ENABLED;
+
+                        pf->flags |= I40E_FLAG_DCB_CAPABLE;
+                        /* Enable DCB tagging only when more than one TC */
+                        if (i40e_dcb_get_num_tc(&hw->local_dcbx_config) > 1)
+                                pf->flags |= I40E_FLAG_DCB_ENABLED;
                 }
         } else {
                 dev_info(&pf->pdev->dev, "AQ Querying DCB configuration failed: %d\n",
@@ -4685,6 +4689,10 @@ static int i40e_handle_lldp_event(struct i40e_pf *pf,
         int ret = 0;
         u8 type;
 
+        /* Not DCB capable or capability disabled */
+        if (!(pf->flags & I40E_FLAG_DCB_CAPABLE))
+                return ret;
+
         /* Ignore if event is not for Nearest Bridge */
         type = ((mib->type >> I40E_AQ_LLDP_BRIDGE_TYPE_SHIFT)
                 & I40E_AQ_LLDP_BRIDGE_TYPE_MASK);
@@ -4726,6 +4734,12 @@ static int i40e_handle_lldp_event(struct i40e_pf *pf,
         if (!need_reconfig)
                 goto exit;
 
+        /* Enable DCB tagging only when more than one TC */
+        if (i40e_dcb_get_num_tc(dcbx_cfg) > 1)
+                pf->flags |= I40E_FLAG_DCB_ENABLED;
+        else
+                pf->flags &= ~I40E_FLAG_DCB_ENABLED;
+
         /* Reconfiguration needed quiesce all VSIs */
         i40e_pf_quiesce_all_vsi(pf);
 
@@ -6365,7 +6379,7 @@ static void i40e_init_interrupt_scheme(struct i40e_pf *pf)
                 if (err) {
                         pf->flags &= ~(I40E_FLAG_MSIX_ENABLED   |
                                        I40E_FLAG_RSS_ENABLED    |
-                                       I40E_FLAG_DCB_ENABLED    |
+                                       I40E_FLAG_DCB_CAPABLE    |
                                        I40E_FLAG_SRIOV_ENABLED  |
                                        I40E_FLAG_FD_SB_ENABLED  |
                                        I40E_FLAG_FD_ATR_ENABLED |
@@ -8187,13 +8201,13 @@ static void i40e_determine_queue_usage(struct i40e_pf *pf)
                 pf->flags &= ~(I40E_FLAG_RSS_ENABLED    |
                                I40E_FLAG_FD_SB_ENABLED  |
                                I40E_FLAG_FD_ATR_ENABLED |
-                               I40E_FLAG_DCB_ENABLED    |
+                               I40E_FLAG_DCB_CAPABLE    |
                                I40E_FLAG_SRIOV_ENABLED  |
                                I40E_FLAG_VMDQ_ENABLED);
         } else if (!(pf->flags & (I40E_FLAG_RSS_ENABLED |
                                   I40E_FLAG_FD_SB_ENABLED |
                                   I40E_FLAG_FD_ATR_ENABLED |
-                                  I40E_FLAG_DCB_ENABLED))) {
+                                  I40E_FLAG_DCB_CAPABLE))) {
                 /* one qp for PF */
                 pf->rss_size = pf->num_lan_qps = 1;
                 queues_left -= pf->num_lan_qps;
@@ -8205,9 +8219,9 @@ static void i40e_determine_queue_usage(struct i40e_pf *pf)
                                I40E_FLAG_VMDQ_ENABLED);
         } else {
                 /* Not enough queues for all TCs */
-                if ((pf->flags & I40E_FLAG_DCB_ENABLED) &&
+                if ((pf->flags & I40E_FLAG_DCB_CAPABLE) &&
                     (queues_left < I40E_MAX_TRAFFIC_CLASS)) {
-                        pf->flags &= ~I40E_FLAG_DCB_ENABLED;
+                        pf->flags &= ~I40E_FLAG_DCB_CAPABLE;
                         dev_info(&pf->pdev->dev, "not enough queues for DCB. DCB is disabled.\n");
                 }
                 pf->num_lan_qps = pf->rss_size_max;
@@ -8300,7 +8314,7 @@ static void i40e_print_features(struct i40e_pf *pf)
                 buf += sprintf(buf, "FD_SB ");
                 buf += sprintf(buf, "NTUPLE ");
         }
-        if (pf->flags & I40E_FLAG_DCB_ENABLED)
+        if (pf->flags & I40E_FLAG_DCB_CAPABLE)
                 buf += sprintf(buf, "DCB ");
         if (pf->flags & I40E_FLAG_PTP)
                 buf += sprintf(buf, "PTP ");
@@ -8486,7 +8500,7 @@ static int i40e_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
         err = i40e_init_pf_dcb(pf);
         if (err) {
                 dev_info(&pdev->dev, "init_pf_dcb failed: %d\n", err);
-                pf->flags &= ~I40E_FLAG_DCB_ENABLED;
+                pf->flags &= ~I40E_FLAG_DCB_CAPABLE;
                 /* Continue without DCB enabled */
         }
 #endif /* CONFIG_I40E_DCB */