[3.16.y-ckt stable] Patch "net: can: xilinx_can: fix extended frame handling" 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: can: xilinx_can: fix extended frame handling

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt13.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From a463342c4dacef57fe44e9e4fb5d90027f10ac8e Mon Sep 17 00:00:00 2001
From: Jeppe Ledet-Pedersen <jlp at gomspace.com>
Date: Wed, 29 Apr 2015 17:05:01 +0200
Subject: net: can: xilinx_can: fix extended frame handling

commit 5793affe8c723ece8114b898ab9003c7d97f86d1 upstream.

Using IDR_SRR in RXFIFO_ID to test for the presence of data is only
valid for standard frames. For extended frames the bit is always 1 and
IDR_RTR should be used instead. This patch switches the check to use
CAN_RTR_FLAG which is correctly set when reading the ID.

The patch also changes the DW1/DW2 to be read unconditionally, since
this is necessary to remove the frame from the RXFIFO.

Signed-off-by: Jeppe Ledet-Pedersen <jlp at gomspace.com>
Acked-by: Kedareswara rao Appana <appanad at xilinx.com>
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/can/xilinx_can.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
index 5e8b5609c067..479e962c0492 100644
--- a/drivers/net/can/xilinx_can.c
+++ b/drivers/net/can/xilinx_can.c
@@ -508,10 +508,11 @@ static int xcan_rx(struct net_device *ndev)
 			cf->can_id |= CAN_RTR_FLAG;
 	}

-	if (!(id_xcan & XCAN_IDR_SRR_MASK)) {
-		data[0] = priv->read_reg(priv, XCAN_RXFIFO_DW1_OFFSET);
-		data[1] = priv->read_reg(priv, XCAN_RXFIFO_DW2_OFFSET);
+	/* DW1/DW2 must always be read to remove message from RXFIFO */
+	data[0] = priv->read_reg(priv, XCAN_RXFIFO_DW1_OFFSET);
+	data[1] = priv->read_reg(priv, XCAN_RXFIFO_DW2_OFFSET);

+	if (!(cf->can_id & CAN_RTR_FLAG)) {
 		/* Change Xilinx CAN data format to socketCAN data format */
 		if (cf->can_dlc > 0)
 			*(__be32 *)(cf->data) = cpu_to_be32(data[0]);