ixgbe: add a callback to set the maximum transmit bitrate

This commit adds a callback which allows to adjust the maximum transmit
bitrate the card can output. This makes it possible to get a smooth
traffic instead of the default burst-y behaviour when trying to output
e.g. a video stream.

Much of the logic needed to get a correct bcnrc_val was taken from the
ixgbe_set_vf_rate_limit() function.

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 0f007d9..115656c 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1078,6 +1078,36 @@ static void ixgbe_tx_timeout_reset(struct ixgbe_adapter *adapter)
 }
 
 /**
+ * ixgbe_tx_maxrate - callback to set the maximum per-queue bitrate
+ **/
+static int ixgbe_tx_maxrate(struct net_device *netdev,
+                           int queue_index, u32 maxrate)
+{
+       struct ixgbe_adapter *adapter = netdev_priv(netdev);
+       struct ixgbe_hw *hw = &adapter->hw;
+       u32 bcnrc_val = ixgbe_link_mbps(adapter);
+
+       if (!maxrate)
+               return 0;
+
+       /* Calculate the rate factor values to set */
+       bcnrc_val <<= IXGBE_RTTBCNRC_RF_INT_SHIFT;
+       bcnrc_val /= maxrate;
+
+       /* clear everything but the rate factor */
+       bcnrc_val &= IXGBE_RTTBCNRC_RF_INT_MASK |
+       IXGBE_RTTBCNRC_RF_DEC_MASK;
+
+       /* enable the rate scheduler */
+       bcnrc_val |= IXGBE_RTTBCNRC_RS_ENA;
+
+       IXGBE_WRITE_REG(hw, IXGBE_RTTDQSEL, queue_index);
+       IXGBE_WRITE_REG(hw, IXGBE_RTTBCNRC, bcnrc_val);
+
+       return 0;
+}
+
+/**
  * ixgbe_clean_tx_irq - Reclaim resources after transmit completes
  * @q_vector: structure containing interrupt and ring information
  * @tx_ring: tx ring to clean
@@ -8807,6 +8837,7 @@ static const struct net_device_ops ixgbe_netdev_ops = {
        .ndo_set_mac_address    = ixgbe_set_mac,
        .ndo_change_mtu         = ixgbe_change_mtu,
        .ndo_tx_timeout         = ixgbe_tx_timeout,
+       .ndo_set_tx_maxrate     = ixgbe_tx_maxrate,
        .ndo_vlan_rx_add_vid    = ixgbe_vlan_rx_add_vid,
        .ndo_vlan_rx_kill_vid   = ixgbe_vlan_rx_kill_vid,
        .ndo_do_ioctl           = ixgbe_ioctl,

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
index 4bc2496..adcf000 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
@@ -1398,7 +1398,7 @@ out:
        return err;
 }
 
-static int ixgbe_link_mbps(struct ixgbe_adapter *adapter)
+int ixgbe_link_mbps(struct ixgbe_adapter *adapter)
 {
        switch (adapter->link_speed) {
        case IXGBE_LINK_SPEED_100_FULL:

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h
index dad9257..47e65e2 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.h
@@ -44,6 +44,7 @@ void ixgbe_ping_all_vfs(struct ixgbe_adapter *adapter);
 int ixgbe_ndo_set_vf_mac(struct net_device *netdev, int queue, u8 *mac);
 int ixgbe_ndo_set_vf_vlan(struct net_device *netdev, int queue, u16 vlan,
                           u8 qos);
+int ixgbe_link_mbps(struct ixgbe_adapter *adapter);
 int ixgbe_ndo_set_vf_bw(struct net_device *netdev, int vf, int min_tx_rate,
                        int max_tx_rate);
 int ixgbe_ndo_set_vf_spoofchk(struct net_device *netdev, int vf, bool setting);