[ 3.5.y.z extended stable ] Patch "net: sh_eth: fix incorrect RX length error if R8A7740" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    net: sh_eth: fix incorrect RX length error if R8A7740

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From a1ffb8e6418f97e53881b53125d574f7c17bdd4f Mon Sep 17 00:00:00 2001
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh at renesas.com>
Date: Thu, 13 Jun 2013 10:15:45 +0900
Subject: [PATCH] net: sh_eth: fix incorrect RX length error if R8A7740

commit dd019897358b815f7828dab90b51d51df4d3658d upstream.

This patch fixes an issue that the driver increments the "RX length error"
on every buffer in sh_eth_rx() if the R8A7740.
This patch also adds a description about the Receive Frame Status bits.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh at renesas.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/renesas/sh_eth.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 79bf09b..2ff4f0b 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1027,16 +1027,23 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status)
 		desc_status = edmac_to_cpu(mdp, rxdesc->status);
 		pkt_len = rxdesc->frame_length;

-#if defined(CONFIG_ARCH_R8A7740)
-		desc_status >>= 16;
-#endif
-
 		if (--boguscnt < 0)
 			break;

 		if (!(desc_status & RDFEND))
 			ndev->stats.rx_length_errors++;

+#if defined(CONFIG_ARCH_R8A7740)
+		/*
+		 * In case of almost all GETHER/ETHERs, the Receive Frame State
+		 * (RFS) bits in the Receive Descriptor 0 are from bit 9 to
+		 * bit 0. However, in case of the R8A7740's GETHER, the RFS
+		 * bits are from bit 25 to bit 16. So, the driver needs right
+		 * shifting by 16.
+		 */
+		desc_status >>= 16;
+#endif
+
 		if (desc_status & (RD_RFS1 | RD_RFS2 | RD_RFS3 | RD_RFS4 |
 				   RD_RFS5 | RD_RFS6 | RD_RFS10)) {
 			ndev->stats.rx_errors++;
--
1.8.1.2