Date:	Fri, 31 Jul 2015 18:38:32 +0300
From:	Claudiu Manoil <claudiu.manoil@...escale.com>
To:	<netdev@...r.kernel.org>
CC:	"David S. Miller" <davem@...emloft.net>
Subject: [PATCH net 2/3] gianfar: Fix suspend/resume for wol magic packet

If we disable NAPI in the first place we can mask the device's
interrupts (and halt it) without fearing that imask may be
concurrently accessed from interrupt context, so there's
no need to do local_irq_save() around gfar_halt_nodisable().
lock_rx_qs()/unlock_tx_qs() are just obsoleted and potentially
buggy routines.  The txlock is currently used in the driver only
to manage TX congestion, it has nothing to do with halting the
device.  With these changes, the TX processing is stopped before
gfar_halt().

Compact gfar_halt() is used instead of gfar_halt_nodisable(),
as it disables Rx/TX DMA h/w blocks and the Rx/TX h/w queues.
gfar_start() re-enables all these blocks on resume.  Enabling
the magic-packet mode remains the same, note that the RX block
is re-enabled just before entering sleep mode.

Add IRQF_NO_SUSPEND flag for the error interrupt line, to signal
that the interrupt line must remain active during sleep in order
to wake the system by magic packet (MAG) reception interrupt.
(On some systems the MAG interrupt did trigger w/o this flag
as well, but on others it didn't.)

Without these fixes, when suspended during fair Tx traffic the
interface occasionally failed to be woken up by magic packet.

Signed-off-by: Claudiu Manoil <claudiu.manoil@...escale.com>
---
 drivers/net/ethernet/freescale/gianfar.c | 98 ++++++++++----------------------
 1 file changed, 30 insertions(+), 68 deletions(-)

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index caad327..084c25d 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -565,24 +565,6 @@ static void gfar_ints_enable(struct gfar_private *priv)
 	}
 }
 
-#ifdef CONFIG_PM
-static void lock_tx_qs(struct gfar_private *priv)
-{
-	int i;
-
-	for (i = 0; i < priv->num_tx_queues; i++)
-		spin_lock(&priv->tx_queue[i]->txlock);
-}
-
-static void unlock_tx_qs(struct gfar_private *priv)
-{
-	int i;
-
-	for (i = 0; i < priv->num_tx_queues; i++)
-		spin_unlock(&priv->tx_queue[i]->txlock);
-}
-#endif
-
 static int gfar_alloc_tx_queues(struct gfar_private *priv)
 {
 	int i;
@@ -1542,48 +1524,37 @@ static int gfar_suspend(struct device *dev)
 	struct gfar_private *priv = dev_get_drvdata(dev);
 	struct net_device *ndev = priv->ndev;
 	struct gfar __iomem *regs = priv->gfargrp[0].regs;
-	unsigned long flags;
 	u32 tempval;
-
 	int magic_packet = priv->wol_en &&
 			   (priv->device_flags &
 			    FSL_GIANFAR_DEV_HAS_MAGIC_PACKET);
 
+	if (!netif_running(ndev))
+		return 0;
+
+	disable_napi(priv);
+	netif_tx_lock(ndev);
 	netif_device_detach(ndev);
+	netif_tx_unlock(ndev);
 
-	if (netif_running(ndev)) {
+	gfar_halt(priv);
 
-		local_irq_save(flags);
-		lock_tx_qs(priv);
+	if (magic_packet) {
+		/* Enable interrupt on Magic Packet */
+		gfar_write(&regs->imask, IMASK_MAG);
 
-		gfar_halt_nodisable(priv);
+		/* Enable Magic Packet mode */
+		tempval = gfar_read(&regs->maccfg2);
+		tempval |= MACCFG2_MPEN;
+		gfar_write(&regs->maccfg2, tempval);
 
-		/* Disable Tx, and Rx if wake-on-LAN is disabled. */
+		/* re-enable the Rx block */
 		tempval = gfar_read(&regs->maccfg1);
-
-		tempval &= ~MACCFG1_TX_EN;
-
-		if (!magic_packet)
-			tempval &= ~MACCFG1_RX_EN;
-
+		tempval |= MACCFG1_RX_EN;
 		gfar_write(&regs->maccfg1, tempval);
 
-		unlock_tx_qs(priv);
-		local_irq_restore(flags);
-
-		disable_napi(priv);
-
-		if (magic_packet) {
-			/* Enable interrupt on Magic Packet */
-			gfar_write(&regs->imask, IMASK_MAG);
-
-			/* Enable Magic Packet mode */
-			tempval = gfar_read(&regs->maccfg2);
-			tempval |= MACCFG2_MPEN;
-			gfar_write(&regs->maccfg2, tempval);
-		} else {
-			phy_stop(priv->phydev);
-		}
+	} else {
+		phy_stop(priv->phydev);
 	}
 
 	return 0;
@@ -1594,37 +1565,26 @@ static int gfar_resume(struct device *dev)
 	struct gfar_private *priv = dev_get_drvdata(dev);
 	struct net_device *ndev = priv->ndev;
 	struct gfar __iomem *regs = priv->gfargrp[0].regs;
-	unsigned long flags;
 	u32 tempval;
 	int magic_packet = priv->wol_en &&
 			   (priv->device_flags &
 			    FSL_GIANFAR_DEV_HAS_MAGIC_PACKET);
 
-	if (!netif_running(ndev)) {
-		netif_device_attach(ndev);
+	if (!netif_running(ndev))
 		return 0;
-	}
 
-	if (!magic_packet && priv->phydev)
+	if (magic_packet) {
+		/* Disable Magic Packet mode */
+		tempval = gfar_read(&regs->maccfg2);
+		tempval &= ~MACCFG2_MPEN;
+		gfar_write(&regs->maccfg2, tempval);
+	} else {
 		phy_start(priv->phydev);
-
-	/* Disable Magic Packet mode, in case something
-	 * else woke us up.
-	 */
-	local_irq_save(flags);
-	lock_tx_qs(priv);
-
-	tempval = gfar_read(&regs->maccfg2);
-	tempval &= ~MACCFG2_MPEN;
-	gfar_write(&regs->maccfg2, tempval);
+	}
 
 	gfar_start(priv);
 
-	unlock_tx_qs(priv);
-	local_irq_restore(flags);
-
 	netif_device_attach(ndev);
-
 	enable_napi(priv);
 
 	return 0;
@@ -2047,7 +2007,8 @@ static int register_grp_irqs(struct gfar_priv_grp *grp)
 		/* Install our interrupt handlers for Error,
 		 * Transmit, and Receive
 		 */
-		err = request_irq(gfar_irq(grp, ER)->irq, gfar_error, 0,
+		err = request_irq(gfar_irq(grp, ER)->irq, gfar_error,
+				  IRQF_NO_SUSPEND,
 				  gfar_irq(grp, ER)->name, grp);
 		if (err < 0) {
 			netif_err(priv, intr, dev, "Can't get IRQ %d\n",
@@ -2070,7 +2031,8 @@ static int register_grp_irqs(struct gfar_priv_grp *grp)
 			goto rx_irq_fail;
 		}
 	} else {
-		err = request_irq(gfar_irq(grp, TX)->irq, gfar_interrupt, 0,
+		err = request_irq(gfar_irq(grp, TX)->irq, gfar_interrupt,
+				  IRQF_NO_SUSPEND,
 				  gfar_irq(grp, TX)->name, grp);
 		if (err < 0) {
 			netif_err(priv, intr, dev, "Can't get IRQ %d\n",
-- 
1.7.11.7

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