[PATCH v2 1/2] ucc_geth: Fix half-duplex operation for non-MII/RMII interfaces

[PATCH v2 1/2] ucc_geth: Fix half-duplex operation for non-MII/RMII interfaces

[Anton Vorontsov]

Currently the half-duplex operation seems to not work reliably for
RGMII PHY interfaces. It takes about 10 minutes to boot NFS rootfs
using 10/half link, following symptoms were observed:

  ucc_geth: QE UCC Gigabit Ethernet Controller
  ucc_geth: UCC1 at 0xe0082000 (irq = 32)
  [...]
  Sending DHCP and RARP requests .
  PHY: mdio@e0082120:07 - Link is Up - 10/Half
  ., OK
  [...]
  Looking up port of RPC 100003/2 on 10.0.0.2
  Looking up port of RPC 100005/1 on 10.0.0.2
  VFS: Mounted root (nfs filesystem) readonly on device 0:13.
  Freeing unused kernel memory: 204k init
  eth0: no IPv6 routers present
  nfs: server 10.0.0.2 not responding, still trying
  nfs: server 10.0.0.2 not responding, still trying
  nfs: server 10.0.0.2 not responding, still trying
  nfs: server 10.0.0.2 OK
  nfs: server 10.0.0.2 OK
  nfs: server 10.0.0.2 not responding, still trying
  [... few minutes of OK/not responding flood ...]

The statistic shows that there are indeed some errors:

  # ethtool -S eth0 | grep -v ": 0"
  NIC statistics:
       tx-64-frames: 42
       tx-65-127-frames: 9
       tx-128-255-frames: 4768
       rx-64-frames: 41
       rx-65-127-frames: 260
       rx-128-255-frames: 2679
       tx-bytes-ok: 859634
       tx-multicast-frames: 5
       tx-broadcast-frames: 7
       rx-frames: 8333
       rx-bytes-ok: 8039364
       rx-bytes-all: 8039364
       stats-counter-mask: 4294901760
       tx-single-collision: 324
       tx-multiple-collision: 47
       tx-late-collsion: 604
       tx-aborted-frames: 604
       tx-frames-ok: 4967
       tx-256-511-frames: 3
       tx-512-1023-frames: 79
       tx-1024-1518-frames: 71
       rx-256-511-frames: 37
       rx-512-1023-frames: 73
       rx-1024-1518-frames: 5243

According to current QEIWRM (Rev. 2 5/2009), FDX bit can be 0 for
RGMII(10/100) modes, while MPC8568ERM (Rev. C 02/2007) spec says
that cleared FDX bit is permitted for MII/RMII modes only.

The symptoms above were seen on MPC8569E-MDS boards, so QEIWRM is
clearly wrong, and this patch completely cures the problems above.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
---
 drivers/net/ucc_geth.c |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 464df03..0c26a59 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -1469,12 +1469,18 @@ static void adjust_link(struct net_device *dev)
 	if (phydev->link) {
 		u32 tempval = in_be32(&ug_regs->maccfg2);
 		u32 upsmr = in_be32(&uf_regs->upsmr);
+		phy_interface_t phyi = ugeth->phy_interface;
+
 		/* Now we make sure that we can be in full duplex mode.
 		 * If not, we operate in half-duplex mode. */
 		if (phydev->duplex != ugeth->oldduplex) {
 			new_state = 1;
-			if (!(phydev->duplex))
-				tempval &= ~(MACCFG2_FDX);
+			if (!phydev->duplex &&
+					(phyi == PHY_INTERFACE_MODE_MII ||
+					 phyi == PHY_INTERFACE_MODE_RMII ||
+					 (phyi == PHY_INTERFACE_MODE_GMII &&
+					  phydev->speed < 1000)))
+				tempval &= ~MACCFG2_FDX;
 			else
 				tempval |= MACCFG2_FDX;
 			ugeth->oldduplex = phydev->duplex;
-- 
1.6.3.1

Re: [PATCH v2 1/2] ucc_geth: Fix half-duplex operation for non-MII/RMII interfaces

[Anton Vorontsov]

On Thu, Jun 25, 2009 at 05:02:32AM +0400, Anton Vorontsov wrote:
> Currently the half-duplex operation seems to not work reliably for
> RGMII PHY interfaces. It takes about 10 minutes to boot NFS rootfs
> using 10/half link, following symptoms were observed:

David, please ignore these patches, they just appear to
workaround the issue, but they don't fix the root cause (which
is unknown yet), and may cause other side to see the duplex
errors. Heh...

Thanks,

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2

Re: [PATCH v2 1/2] ucc_geth: Fix half-duplex operation for non-MII/RMII interfaces

[David Miller]

From: Anton Vorontsov <avorontsov@ru.mvista.com>
Date: Thu, 25 Jun 2009 11:08:13 +0400

> On Thu, Jun 25, 2009 at 05:02:32AM +0400, Anton Vorontsov wrote:
>> Currently the half-duplex operation seems to not work reliably for
>> RGMII PHY interfaces. It takes about 10 minutes to boot NFS rootfs
>> using 10/half link, following symptoms were observed:
> 
> David, please ignore these patches, they just appear to
> workaround the issue, but they don't fix the root cause (which
> is unknown yet), and may cause other side to see the duplex
> errors. Heh...

Ok, thanks for the heads-up.