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, 96 insertions, 0 deletions

diff --git a/target/linux/mvebu/patches-4.4/300-reprobe_sfp_phy.patch b/target/linux/mvebu/patches-4.4/300-reprobe_sfp_phy.patch
new file mode 100644
index 0000000..42614ef
--- /dev/null
+++ b/target/linux/mvebu/patches-4.4/300-reprobe_sfp_phy.patch
@@ -0,0 +1,96 @@
+From 28baa5e2635285b178326b301f534ed95c65dd01 Mon Sep 17 00:00:00 2001
+From: Jonas Gorski <jonas.gorski@gmail.com>
+Date: Thu, 29 Sep 2016 11:44:39 +0200
+Subject: [PATCH] sfp: retry phy probe if unsuccessful
+
+Some phys seem to take longer than 50 ms to come out of reset, so retry
+until we find a phy.
+
+Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
+---
+ drivers/net/phy/sfp.c | 38 +++++++++++++++++++++++++-------------
+ 1 file changed, 25 insertions(+), 13 deletions(-)
+
+--- a/drivers/net/phy/sfp.c
++++ b/drivers/net/phy/sfp.c
+@@ -488,7 +488,7 @@ static void sfp_sm_phy_detach(struct sfp
+ 	sfp->mod_phy = NULL;
+ }
+ 
+-static void sfp_sm_probe_phy(struct sfp *sfp)
++static int sfp_sm_probe_phy(struct sfp *sfp)
+ {
+ 	struct phy_device *phy;
+ 	int err;
+@@ -498,11 +498,11 @@ static void sfp_sm_probe_phy(struct sfp
+ 	phy = mdiobus_scan(sfp->i2c_mii, SFP_PHY_ADDR);
+ 	if (IS_ERR(phy)) {
+ 		dev_err(sfp->dev, "mdiobus scan returned %ld\n", PTR_ERR(phy));
+-		return;
++		return PTR_ERR(phy);
+ 	}
+ 	if (!phy) {
+-		dev_info(sfp->dev, "no PHY detected\n");
+-		return;
++		dev_dbg(sfp->dev, "no PHY detected\n");
++		return -EAGAIN;
+ 	}
+ 
+ 	err = phylink_connect_phy(sfp->phylink, phy);
+@@ -510,11 +510,13 @@ static void sfp_sm_probe_phy(struct sfp
+ 		phy_device_remove(phy);
+ 		phy_device_free(phy);
+ 		dev_err(sfp->dev, "phylink_connect_phy failed: %d\n", err);
+-		return;
++		return err;
+ 	}
+ 
+ 	sfp->mod_phy = phy;
+ 	phy_start(phy);
++
++	return 0;
+ }
+ 
+ static void sfp_sm_link_up(struct sfp *sfp)
+@@ -565,13 +567,6 @@ static void sfp_sm_mod_init(struct sfp *
+ {
+ 	sfp_module_tx_enable(sfp);
+ 
+-	/* Wait t_init before indicating that the link is up, provided the
+-	 * current state indicates no TX_FAULT.  If TX_FAULT clears before
+-	 * this time, that's fine too.
+-	 */
+-	sfp_sm_next(sfp, SFP_S_INIT, T_INIT_JIFFIES);
+-	sfp->sm_retries = 5;
+-
+ 	if (sfp->phylink) {
+ 		/* Setting the serdes link mode is guesswork: there's no
+ 		 * field in the EEPROM which indicates what mode should
+@@ -587,9 +582,26 @@ static void sfp_sm_mod_init(struct sfp *
+ 		    !sfp->id.base.e100_base_fx) {
+ 			phylink_set_link_an_mode(sfp->phylink, MLO_AN_8023Z);
+ 		} else {
++			int ret;
++
+ 			phylink_set_link_an_mode(sfp->phylink, MLO_AN_SGMII);
+-			sfp_sm_probe_phy(sfp);
++
++			ret = sfp_sm_probe_phy(sfp);
++			if (ret) {
++				if (ret == -EAGAIN)
++					sfp_sm_set_timer(sfp, T_PROBE_RETRY);
++				else
++					sfp_sm_next(sfp, SFP_S_TX_DISABLE, 0);
++				return;
++			}
+ 		}
++
++		/* Wait t_init before indicating that the link is up, provided the
++		 * current state indicates no TX_FAULT.  If TX_FAULT clears before
++		 * this time, that's fine too.
++		 */
++		sfp_sm_next(sfp, SFP_S_INIT, T_INIT_JIFFIES);
++		sfp->sm_retries = 5;
+ 	}
+ }
+