ice: Add feature bitmap, helpers and a check for DSCP

DSCP a.k.a L3 QoS is only supported on certain devices. To enforce this,
this patch introduces a bitmap of features and helper functions.

The feature bitmap is set based on device IDs on driver init. Currently,
DSCP is the only feature in this bitmap, but there will be more in the
future. In the DCB netlink flow, check if the feature bit is set before
exercising DSCP.

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_lib.c

@@ -3573,3 +3573,50 @@ int ice_set_link(struct ice_vsi *vsi, bool ena)
 
 	return 0;
 }
+
+/**
+ * ice_is_feature_supported
+ * @pf: pointer to the struct ice_pf instance
+ * @f: feature enum to be checked
+ *
+ * returns true if feature is supported, false otherwise
+ */
+bool ice_is_feature_supported(struct ice_pf *pf, enum ice_feature f)
+{
+	if (f < 0 || f >= ICE_F_MAX)
+		return false;
+
+	return test_bit(f, pf->features);
+}
+
+/**
+ * ice_set_feature_support
+ * @pf: pointer to the struct ice_pf instance
+ * @f: feature enum to set
+ */
+static void ice_set_feature_support(struct ice_pf *pf, enum ice_feature f)
+{
+	if (f < 0 || f >= ICE_F_MAX)
+		return;
+
+	set_bit(f, pf->features);
+}
+
+/**
+ * ice_init_feature_support
+ * @pf: pointer to the struct ice_pf instance
+ *
+ * called during init to setup supported feature
+ */
+void ice_init_feature_support(struct ice_pf *pf)
+{
+	switch (pf->hw.device_id) {
+	case ICE_DEV_ID_E810C_BACKPLANE:
+	case ICE_DEV_ID_E810C_QSFP:
+	case ICE_DEV_ID_E810C_SFP:
+		ice_set_feature_support(pf, ICE_F_DSCP);
+		break;
+	default:
+		break;
+	}
+}