[ovs-dev] [PATCH] netdev-dpdk: Add Flow Control support.

[Sugesh Chandran]

Add support for flow-control(mac control frame) to DPDK enabled physical
port types. By default, the flow-control is OFF on both rx and tx side.
The flow control can be enabled/disabled either when adding a port to OVS
or at run time.

For eg:
To enable flow control support at tx side while adding a port, add the
'tx-flow-ctrl' option to the 'ovs-vsctl add-port' command-line as below.

 'ovs-vsctl add-port br0 dpdk0 -- \
  set Interface dpdk0 type=dpdk options:tx-flow-ctrl=on'

Similarly to enable rx flow control,
 'ovs-vsctl add-port br0 dpdk0 -- \
  set Interface dpdk0 type=dpdk options:rx-flow-ctrl=on'

And to enable the flow control auto-negotiation,
 'ovs-vsctl add-port br0 dpdk0 -- \
  set Interface dpdk0 type=dpdk options:flow-ctrl-autoneg=on'

To turn ON the tx flow control at run time(After the port is being added
to OVS), the command-line input will be,
 'ovs-vsctl set Interface dpdk0 options:tx-flow-ctrl=on'

The flow control parameters can be turned off by setting 'off' to the
respective parameter. To turn off the flow control at tx side,
 'ovs-vsctl set Interface dpdk0 options:tx-flow-ctrl=off'

Signed-off-by: Sugesh Chandran <sugesh.chandran at intel.com>
---
 lib/netdev-dpdk.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 85b18fd..74efd25 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -634,6 +634,67 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int n_rxq, int n_txq)
     return diag;
 }
 
+static void
+dpdk_eth_parse_flow_ctrl(struct netdev_dpdk *dev,
+                         const struct smap *args,
+                         struct rte_eth_fc_conf *fc_conf)
+                         OVS_REQUIRES(dev->mutex)
+{
+    int ret = 0;
+    int rx_fc_en = 0;
+    int tx_fc_en = 0;
+    const char *rx_flow_mode;
+    const char *tx_flow_mode;
+    const char *flow_autoneg;
+    enum rte_eth_fc_mode fc_mode_set[2][2] = {{RTE_FC_NONE, RTE_FC_TX_PAUSE},
+                                              {RTE_FC_RX_PAUSE, RTE_FC_FULL}
+                                             };
+
+    ret = rte_eth_dev_flow_ctrl_get(dev->port_id, fc_conf);
+    if (ret != 0) {
+        VLOG_DBG("cannot get flow control parameters on port=%d, err=%s",
+                 dev->port_id, rte_strerror(ret));
+        return;
+    }
+    rx_flow_mode = smap_get(args, "rx-flow-ctrl");
+    tx_flow_mode = smap_get(args, "tx-flow-ctrl");
+    flow_autoneg = smap_get(args, "flow-ctrl-autoneg");
+    if (rx_flow_mode) {
+        if (!strcmp(rx_flow_mode, "on")) {
+            rx_fc_en = 1;
+        }
+        else if (!strcmp(rx_flow_mode, "off")) {
+            rx_fc_en = 0;
+        }
+    }
+    if (tx_flow_mode) {
+        if (!strcmp(tx_flow_mode, "on")) {
+            tx_fc_en =1;
+        }
+        else if (!strcmp(tx_flow_mode, "off")) {
+            tx_fc_en =0;
+        }
+    }
+    if (flow_autoneg) {
+        if (!strcmp(flow_autoneg, "on")) {
+            fc_conf->autoneg = 1;
+        }
+        else if (!strcmp(flow_autoneg, "off")) {
+            fc_conf->autoneg = 0;
+        }
+    }
+    fc_conf->mode = fc_mode_set[tx_fc_en][rx_fc_en];
+}
+
+static void
+dpdk_eth_flow_ctrl_config(struct netdev_dpdk *dev,
+                          struct rte_eth_fc_conf *fc_conf)
+                          OVS_REQUIRES(dev->mutex)
+{
+    if (rte_eth_dev_flow_ctrl_set(dev->port_id, fc_conf) != 0) {
+        VLOG_ERR("Failed to enable flow control on device %d", dev->port_id);
+    }
+}
 
 static int
 dpdk_eth_dev_init(struct netdev_dpdk *dev) OVS_REQUIRES(dpdk_mutex)
@@ -991,6 +1052,13 @@ netdev_dpdk_set_config(struct netdev *netdev, const struct smap *args)
         dev->requested_n_rxq = new_n_rxq;
         netdev_request_reconfigure(netdev);
     }
+
+    /* Flow control configuration for DPDK Ethernet ports. */
+    if (dev->type == DPDK_DEV_ETH) {
+        struct rte_eth_fc_conf fc_conf = {0};
+        dpdk_eth_parse_flow_ctrl(dev, args, &fc_conf);
+        dpdk_eth_flow_ctrl_config(dev, &fc_conf);
+    }
     ovs_mutex_unlock(&dev->mutex);
 
     return 0;
-- 
2.5.0