[patch 37/47] forcedeth: msi interrupts

[Greg KH]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Ayaz Abdulla <aabdulla@xxxxxxxxxx>

commit 4db0ee176e256444695ee2d7b004552e82fec987 upstream

Add a workaround for lost MSI interrupts.  There is a race condition in
the HW in which future interrupts could be missed.  The workaround is to
toggle the MSI irq mask.

Added cleanup based on comments from Andrew Morton.

Signed-off-by: Ayaz Abdulla <aabdulla@xxxxxxxxxx>
Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Cc: Jeff Garzik <jeff@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jeff Garzik <jgarzik@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/net/forcedeth.c |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -3111,6 +3111,20 @@ static void nv_link_irq(struct net_devic
 	dprintk(KERN_DEBUG "%s: link change notification done.\n", dev->name);
 }
 
+static void nv_msi_workaround(struct fe_priv *np)
+{
+
+	/* Need to toggle the msi irq mask within the ethernet device,
+	 * otherwise, future interrupts will not be detected.
+	 */
+	if (np->msi_flags & NV_MSI_ENABLED) {
+		u8 __iomem *base = np->base;
+
+		writel(0, base + NvRegMSIIrqMask);
+		writel(NVREG_MSI_VECTOR_0_ENABLED, base + NvRegMSIIrqMask);
+	}
+}
+
 static irqreturn_t nv_nic_irq(int foo, void *data)
 {
 	struct net_device *dev = (struct net_device *) data;
@@ -3133,6 +3147,8 @@ static irqreturn_t nv_nic_irq(int foo, v
 		if (!(events & np->irqmask))
 			break;
 
+		nv_msi_workaround(np);
+
 		spin_lock(&np->lock);
 		nv_tx_done(dev);
 		spin_unlock(&np->lock);
@@ -3248,6 +3264,8 @@ static irqreturn_t nv_nic_irq_optimized(
 		if (!(events & np->irqmask))
 			break;
 
+		nv_msi_workaround(np);
+
 		spin_lock(&np->lock);
 		nv_tx_done_optimized(dev, TX_WORK_PER_LOOP);
 		spin_unlock(&np->lock);
@@ -3588,6 +3606,8 @@ static irqreturn_t nv_nic_irq_test(int f
 	if (!(events & NVREG_IRQ_TIMER))
 		return IRQ_RETVAL(0);
 
+	nv_msi_workaround(np);
+
 	spin_lock(&np->lock);
 	np->intr_test = 1;
 	spin_unlock(&np->lock);

-- 
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