| From | Ben Hutchings <> | Date | Sun, 29 Dec 2013 03:08:43 +0100 | Subject | [PATCH 3.2 020/185] can: c_can: Fix RX message handling, handle lost message before EOB |
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3.2.54-rc1 review patch. If anyone has any objections, please let me know.
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From: Markus Pargmann <mpa@pengutronix.de>
commit 5d0f801a2ccec3b1fdabc3392c8d99ed0413d216 upstream.
If we handle end of block messages with higher priority than a lost message, we can run into an endless interrupt loop.
This is reproducable with a am335x processor and "cansequence -r" at 1Mbit. As soon as we loose a packet we can't escape from an interrupt loop.
This patch fixes the problem by handling lost packets before EOB packets.
Signed-off-by: Markus Pargmann <mpa@pengutronix.de> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/net/can/c_can/c_can.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -764,9 +764,6 @@ static int c_can_do_rx_poll(struct net_d msg_ctrl_save = priv->read_reg(priv, &priv->regs->ifregs[0].msg_cntrl); - if (msg_ctrl_save & IF_MCONT_EOB) - return num_rx_pkts; - if (msg_ctrl_save & IF_MCONT_MSGLST) { c_can_handle_lost_msg_obj(dev, 0, msg_obj); num_rx_pkts++; @@ -774,6 +771,9 @@ static int c_can_do_rx_poll(struct net_d continue; } + if (msg_ctrl_save & IF_MCONT_EOB) + return num_rx_pkts; + if (!(msg_ctrl_save & IF_MCONT_NEWDAT)) continue;
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