[PATCH v2 3/3] ucc_geth: Fix hangs after switching from full to half duplex

[Anton Vorontsov]

MPC8360 QE UCC ethernet controllers hang when changing link duplex
under a load (a bit of NFS activity is enough).

  PHY: mdio at e0102120:00 - Link is Up - 1000/Full
  sh-3.00# ethtool -s eth0 speed 100 duplex half autoneg off
  PHY: mdio at e0102120:00 - Link is Down
  PHY: mdio at e0102120:00 - Link is Up - 100/Half
  NETDEV WATCHDOG: eth0 (ucc_geth): transmit queue 0 timed out
  ------------[ cut here ]------------
  Badness at c01fcbd0 [verbose debug info unavailable]
  NIP: c01fcbd0 LR: c01fcbd0 CTR: c0194e44
  ...

The cure is to disable the controller before changing speed/duplex
and enable it afterwards.

Since ugeth_graceful_stop_{tx,rx} now may be called from an atomic
context, switch the two functions from msleep() to mdelay().

Signed-off-by: Anton Vorontsov <avorontsov at ru.mvista.com>
---

v2: Switch ugeth_graceful_stop_{tx,rx} to mdelay. Noticed with
    CONFIG_DEBUG_SPINLOCK_SLEEP.

 drivers/net/ucc_geth.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 2a2c973..5a0803f 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -1432,7 +1432,7 @@ static int ugeth_graceful_stop_tx(struct ucc_geth_private *ugeth)
 
 	/* Wait for command to complete */
 	do {
-		msleep(10);
+		mdelay(10);
 		temp = in_be32(uccf->p_ucce);
 	} while (!(temp & UCC_GETH_UCCE_GRA) && --i);
 
@@ -1464,7 +1464,7 @@ static int ugeth_graceful_stop_rx(struct ucc_geth_private *ugeth)
 						ucc_num);
 		qe_issue_cmd(QE_GRACEFUL_STOP_RX, cecr_subblock,
 			     QE_CR_PROTOCOL_ETHERNET, 0);
-		msleep(10);
+		mdelay(10);
 		temp = in_8(&ugeth->p_rx_glbl_pram->rxgstpack);
 	} while (!(temp & GRACEFUL_STOP_ACKNOWLEDGE_RX) && --i);
 
@@ -1631,9 +1631,13 @@ static void adjust_link(struct net_device *dev)
 			ugeth->oldspeed = phydev->speed;
 		}
 
+		ugeth_disable(ugeth, COMM_DIR_RX_AND_TX);
+
 		out_be32(&ug_regs->maccfg2, tempval);
 		out_be32(&uf_regs->upsmr, upsmr);
 
+		ugeth_enable(ugeth, COMM_DIR_RX_AND_TX);
+
 		if (!ugeth->oldlink) {
 			new_state = 1;
 			ugeth->oldlink = 1;
-- 
1.6.3.3