Revert "mvebu: remove linux 4.4 support"

This reverts commit 51397d7d95d9f5e210a5557f65de1fa21e6f5921.
There are some unresolved random crashes on WRT1900AC v1 that still need
to be sorted out

Signed-off-by: Felix Fietkau <nbd@nbd.name>

1 files changed, 75 insertions, 0 deletions

diff --git a/target/linux/mvebu/patches-4.4/050-net-mvneta-fix-changing-MTU-when-using-per-cpu-proce.patch b/target/linux/mvebu/patches-4.4/050-net-mvneta-fix-changing-MTU-when-using-per-cpu-proce.patch
new file mode 100644
index 0000000000..07862008a7
--- /dev/null
+++ b/target/linux/mvebu/patches-4.4/050-net-mvneta-fix-changing-MTU-when-using-per-cpu-proce.patch
@@ -0,0 +1,75 @@
+From: Marcin Wojtas <mw@semihalf.com>
+Date: Fri, 1 Apr 2016 15:21:18 +0200
+Subject: [PATCH] net: mvneta: fix changing MTU when using per-cpu processing
+
+After enabling per-cpu processing it appeared that under heavy load
+changing MTU can result in blocking all port's interrupts and
+transmitting data is not possible after the change.
+
+This commit fixes above issue by disabling percpu interrupts for the
+time, when TXQs and RXQs are reconfigured.
+
+Signed-off-by: Marcin Wojtas <mw@semihalf.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+
+--- a/drivers/net/ethernet/marvell/mvneta.c
++++ b/drivers/net/ethernet/marvell/mvneta.c
+@@ -3040,6 +3040,20 @@ static int mvneta_check_mtu_valid(struct
+ 	return mtu;
+ }
+ 
++static void mvneta_percpu_enable(void *arg)
++{
++	struct mvneta_port *pp = arg;
++
++	enable_percpu_irq(pp->dev->irq, IRQ_TYPE_NONE);
++}
++
++static void mvneta_percpu_disable(void *arg)
++{
++	struct mvneta_port *pp = arg;
++
++	disable_percpu_irq(pp->dev->irq);
++}
++
+ /* Change the device mtu */
+ static int mvneta_change_mtu(struct net_device *dev, int mtu)
+ {
+@@ -3064,6 +3078,7 @@ static int mvneta_change_mtu(struct net_
+ 	 * reallocation of the queues
+ 	 */
+ 	mvneta_stop_dev(pp);
++	on_each_cpu(mvneta_percpu_disable, pp, true);
+ 
+ 	mvneta_cleanup_txqs(pp);
+ 	mvneta_cleanup_rxqs(pp);
+@@ -3087,6 +3102,7 @@ static int mvneta_change_mtu(struct net_
+ 		return ret;
+ 	}
+ 
++	on_each_cpu(mvneta_percpu_enable, pp, true);
+ 	mvneta_start_dev(pp);
+ 	mvneta_port_up(pp);
+ 
+@@ -3240,20 +3256,6 @@ static void mvneta_mdio_remove(struct mv
+ 	pp->phy_dev = NULL;
+ }
+ 
+-static void mvneta_percpu_enable(void *arg)
+-{
+-	struct mvneta_port *pp = arg;
+-
+-	enable_percpu_irq(pp->dev->irq, IRQ_TYPE_NONE);
+-}
+-
+-static void mvneta_percpu_disable(void *arg)
+-{
+-	struct mvneta_port *pp = arg;
+-
+-	disable_percpu_irq(pp->dev->irq);
+-}
+-
+ /* Electing a CPU must be done in an atomic way: it should be done
+  * after or before the removal/insertion of a CPU and this function is
+  * not reentrant.