Merge branch 'net-stmmac-further-eee-cleanups-and-one-fix'

Russell King says:

====================
net: stmmac: further EEE cleanups (and one fix!)

This series continues the EEE cleanup of the stmmac driver, and
includes one fix.

As mentioned in the previous series, I wasn't entirely happy with the
"stmmac_disable_sw_eee_mode" name, so the first patch renames this to
"stmmac_stop_sw_lpi" instead, which I think better describes what this
function is doing - stopping the transmit of the LPI state because we
have a packet ot send.

Patch 2 corrects the priv->eee_sw_timer_en flag when EEE has been
disabled. Currently upon disable, priv->eee_enabled is set false,
but through the weird logic that was present prior to the previous
series, priv->eee_sw_timer_en was set true. This behaviour was kept
as the previous series was cleanup, not fixes. This patch fixes this.

Having fixed priv->eee_sw_timer_en to actually indicate whether
software timed EEE mode is being used, it becomes no longer necessary
to test priv->eee_enabled in addition. Patch 3 removes the redundant
test. Patch 4 also uses priv->eee_sw_timer_en before manipulating the
software EEE state in the suspend method rather than using
priv->eee_enabled, which brings consistency.

Patch 5 provides stmmac_try_to_start_sw_lpi() which complements
stmmac_stop_sw_lpi(), and allows us to move duplicated code into one
location.

Patch 6 splits stmmac_enable_eee_mode() - one part of this function
tests whether there are any queues that have unfinished work (in
other words are busy). Separate out this code into a separate function.

Patch 7 also splits out the mod_timer() for the software EEE timer
intoi a seperate function (the reason will be in patch 9.)

Patch 8 merges the remains of stmmac_enable_eee_mode() into
stmmac_try_to_start_sw_lpi().

Patch 9 fixes the delay between transmit and entering LPI. Currently,
when cleaning the transmit queues, if we discover that we have finished
cleaning up all queues, we immediately instruct the hardware to enter
LPI mode without waiting for the LPI timer. However, we should wait for
the LPI timer to expire. Therefore, the transmit cleanup path needs
to call stmmac_restart_sw_lpi_timer() instead of
stmmac_try_to_start_sw_lpi().
====================

Link: https://patch.msgid.link/Z4T84SbaC4D-fN5y@shell.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -400,13 +400,7 @@ static void stmmac_enable_hw_lpi_timer(struct stmmac_priv *priv)
 	stmmac_set_eee_lpi_timer(priv, priv->hw, priv->tx_lpi_timer);
 }
 
-/**
- * stmmac_enable_eee_mode - check and enter in LPI mode
- * @priv: driver private structure
- * Description: this function is to verify and enter in LPI mode in case of
- * EEE.
- */
-static int stmmac_enable_eee_mode(struct stmmac_priv *priv)
+static bool stmmac_eee_tx_busy(struct stmmac_priv *priv)
 {
 	u32 tx_cnt = priv->plat->tx_queues_to_use;
 	u32 queue;
@@ -416,23 +410,42 @@ static int stmmac_enable_eee_mode(struct stmmac_priv *priv)
 		struct stmmac_tx_queue *tx_q = &priv->dma_conf.tx_queue[queue];
 
 		if (tx_q->dirty_tx != tx_q->cur_tx)
-			return -EBUSY; /* still unfinished work */
+			return true; /* still unfinished work */
+	}
+
+	return false;
+}
+
+static void stmmac_restart_sw_lpi_timer(struct stmmac_priv *priv)
+{
+	mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(priv->tx_lpi_timer));
+}
+
+/**
+ * stmmac_try_to_start_sw_lpi - check and enter in LPI mode
+ * @priv: driver private structure
+ * Description: this function is to verify and enter in LPI mode in case of
+ * EEE.
+ */
+static void stmmac_try_to_start_sw_lpi(struct stmmac_priv *priv)
+{
+	if (stmmac_eee_tx_busy(priv)) {
+		stmmac_restart_sw_lpi_timer(priv);
+		return;
 	}
 
 	/* Check and enter in LPI mode */
 	if (!priv->tx_path_in_lpi_mode)
 		stmmac_set_eee_mode(priv, priv->hw,
 			priv->plat->flags & STMMAC_FLAG_EN_TX_LPI_CLOCKGATING);
-	return 0;
 }
 
 /**
- * stmmac_disable_sw_eee_mode - disable and exit from LPI mode
+ * stmmac_stop_sw_lpi - stop transmitting LPI
  * @priv: driver private structure
- * Description: this function is to exit and disable EEE in case of
- * LPI state is true. This is called by the xmit.
+ * Description: When using software-controlled LPI, stop transmitting LPI state.
  */
-static void stmmac_disable_sw_eee_mode(struct stmmac_priv *priv)
+static void stmmac_stop_sw_lpi(struct stmmac_priv *priv)
 {
 	stmmac_reset_eee_mode(priv, priv->hw);
 	del_timer_sync(&priv->eee_ctrl_timer);
@@ -450,8 +463,7 @@ static void stmmac_eee_ctrl_timer(struct timer_list *t)
 {
 	struct stmmac_priv *priv = from_timer(priv, t, eee_ctrl_timer);
 
-	if (stmmac_enable_eee_mode(priv))
-		mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(priv->tx_lpi_timer));
+	stmmac_try_to_start_sw_lpi(priv);
 }
 
 /**
@@ -479,7 +491,7 @@ static void stmmac_eee_init(struct stmmac_priv *priv, bool active)
 	if (!priv->eee_active) {
 		if (priv->eee_enabled) {
 			netdev_dbg(priv->dev, "disable EEE\n");
-			priv->eee_sw_timer_en = true;
+			priv->eee_sw_timer_en = false;
 			stmmac_disable_hw_lpi_timer(priv);
 			del_timer_sync(&priv->eee_ctrl_timer);
 			stmmac_set_eee_timer(priv, priv->hw, 0,
@@ -513,8 +525,7 @@ static void stmmac_eee_init(struct stmmac_priv *priv, bool active)
 		/* Use software LPI mode */
 		priv->eee_sw_timer_en = true;
 		stmmac_disable_hw_lpi_timer(priv);
-		mod_timer(&priv->eee_ctrl_timer,
-			  STMMAC_LPI_T(priv->tx_lpi_timer));
+		stmmac_restart_sw_lpi_timer(priv);
 	}
 
 	priv->eee_enabled = true;
@@ -2783,11 +2794,8 @@ static int stmmac_tx_clean(struct stmmac_priv *priv, int budget, u32 queue,
 			xmits = budget;
 	}
 
-	if (priv->eee_enabled && !priv->tx_path_in_lpi_mode &&
-	    priv->eee_sw_timer_en) {
-		if (stmmac_enable_eee_mode(priv))
-			mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(priv->tx_lpi_timer));
-	}
+	if (priv->eee_sw_timer_en && !priv->tx_path_in_lpi_mode)
+		stmmac_restart_sw_lpi_timer(priv);
 
 	/* We still have pending packets, let's call for a new scheduling */
 	if (tx_q->dirty_tx != tx_q->cur_tx)
@@ -4497,7 +4505,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	first_tx = tx_q->cur_tx;
 
 	if (priv->tx_path_in_lpi_mode && priv->eee_sw_timer_en)
-		stmmac_disable_sw_eee_mode(priv);
+		stmmac_stop_sw_lpi(priv);
 
 	/* Manage oversized TCP frames for GMAC4 device */
 	if (skb_is_gso(skb) && priv->tso) {
@@ -7721,7 +7729,7 @@ int stmmac_suspend(struct device *dev)
 	for (chan = 0; chan < priv->plat->tx_queues_to_use; chan++)
 		hrtimer_cancel(&priv->dma_conf.tx_queue[chan].txtimer);
 
-	if (priv->eee_enabled) {
+	if (priv->eee_sw_timer_en) {
 		priv->tx_path_in_lpi_mode = false;
 		del_timer_sync(&priv->eee_ctrl_timer);
 	}