mvebu: add linux 4.9 support

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/target/linux/mvebu/patches-4.9/409-net-phy-don-t-double-read-clause-45-status-register.patch b/target/linux/mvebu/patches-4.9/409-net-phy-don-t-double-read-clause-45-status-register.patch
new file mode 100644
index 0000000000..ee53fe0380
--- /dev/null
+++ b/target/linux/mvebu/patches-4.9/409-net-phy-don-t-double-read-clause-45-status-register.patch
@@ -0,0 +1,35 @@
+From: Russell King <rmk+kernel@armlinux.org.uk>
+Date: Thu, 5 Jan 2017 00:23:40 +0000
+Subject: [PATCH] net: phy: don't double-read clause 45 status register
+
+One of the design decisions behind the link status bit in the status
+register is that it latches low on link loss.  This is so that link loss
+events are not missed.  Double-reading the status register means that we
+always read the current state of the link, clearing any link loss event.
+
+This can cause problems - for example, if the link has negotiated a
+different set of operating parameters, these will not be communicated
+to the MAC as the PHY state machine will still think that the link has
+remained active.
+
+Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
+---
+
+--- a/drivers/net/phy/phy-c45.c
++++ b/drivers/net/phy/phy-c45.c
+@@ -143,12 +143,9 @@ int genphy_c45_read_link(struct phy_devi
+ 		devad = __ffs(mmd_mask);
+ 		mmd_mask &= ~BIT(devad);
+ 
+-		val = phy_read_mmd(phydev, devad, MDIO_STAT1);
+-		if (val < 0)
+-			return val;
+-
+-		/* Read twice because link state is latched and a
+-		 * read moves the current state into the register
++		/* The link state is latched low so that momentary link
++		 * drops can be detected.  Do not double-read the status
++		 * register if the link is down.
+ 		 */
+ 		val = phy_read_mmd(phydev, devad, MDIO_STAT1);
+ 		if (val < 0)