net: stmmac: reduce unnecessary wakeups from eee sw timer

BugLink: https://bugs.launchpad.net/bugs/1963889
[ Upstream commit c74ead223deb88bdf18af8c772d7ca5a9b6c3c2b ]

Currently, on EEE capable platforms, if EEE SW timer is used, the SW
timer cause 1 wakeup/s even if the TX has successfully entered EEE.
Remove this unnecessary wakeup by only calling mod_timer() if we
haven't successfully entered EEE.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 161e65333ed9486309c152bc8f6727b9282da419..e6af26b2dcb8160dbea6c7fe1c6ac0d9ec0dcb5a 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -400,7 +400,7 @@ static void stmmac_lpi_entry_timer_config(struct stmmac_priv *priv, bool en)
  * Description: this function is to verify and enter in LPI mode in case of
  * EEE.
  */
-static void stmmac_enable_eee_mode(struct stmmac_priv *priv)
+static int stmmac_enable_eee_mode(struct stmmac_priv *priv)
 {
        u32 tx_cnt = priv->plat->tx_queues_to_use;
        u32 queue;
@@ -410,13 +410,14 @@ static void stmmac_enable_eee_mode(struct stmmac_priv *priv)
                struct stmmac_tx_queue *tx_q = &priv->tx_queue[queue];
 
                if (tx_q->dirty_tx != tx_q->cur_tx)
-                       return; /* still unfinished work */
+                       return -EBUSY; /* still unfinished work */
        }
 
        /* Check and enter in LPI mode */
        if (!priv->tx_path_in_lpi_mode)
                stmmac_set_eee_mode(priv, priv->hw,
                                priv->plat->en_tx_lpi_clockgating);
+       return 0;
 }
 
 /**
@@ -448,8 +449,8 @@ static void stmmac_eee_ctrl_timer(struct timer_list *t)
 {
        struct stmmac_priv *priv = from_timer(priv, t, eee_ctrl_timer);
 
-       stmmac_enable_eee_mode(priv);
-       mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(priv->tx_lpi_timer));
+       if (stmmac_enable_eee_mode(priv))
+               mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(priv->tx_lpi_timer));
 }
 
 /**
@@ -2637,8 +2638,8 @@ static int stmmac_tx_clean(struct stmmac_priv *priv, int budget, u32 queue)
 
        if (priv->eee_enabled && !priv->tx_path_in_lpi_mode &&
            priv->eee_sw_timer_en) {
-               stmmac_enable_eee_mode(priv);
-               mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(priv->tx_lpi_timer));
+               if (stmmac_enable_eee_mode(priv))
+                       mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(priv->tx_lpi_timer));
        }
 
        /* We still have pending packets, let's call for a new scheduling */