Messages in this thread Patch in this message | | | Date | Thu, 14 Jun 2012 16:56:55 -0700 | From | Greg KH <> | Subject | [ 32/42] can: c_can: fix "BUG! echo_skb is occupied!" during transmit |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: AnilKumar Ch <anilkumar@ti.com>
commit 617caccebe451716df21c069b079d5936ed7b0f3 upstream.
This patch fixes an issue with transmit routine, which causes "can_put_echo_skb: BUG! echo_skb is occupied!" message when using "cansequence -p" on D_CAN controller.
In c_can driver, while transmitting packets tx_echo flag holds the no of can frames put for transmission into the hardware.
As the comment above c_can_do_tx() indicates, if we find any packet which is not transmitted then we should stop looking for more. In the current implementation this is not taken care of causing the said message.
Also, fix the condition used to find if the packet is transmitted or not. Current code skips the first tx message object and ends up checking one extra invalid object.
While at it, fix the comment on top of c_can_do_tx() to use the terminology "packet" instead of "package" since it is more standard.
Signed-off-by: AnilKumar Ch <anilkumar@ti.com> Acked-by: Wolfgang Grandegger <wg@grandegger.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/net/can/c_can/c_can.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/net/can/c_can/c_can.c +++ b/drivers/net/can/c_can/c_can.c @@ -686,7 +686,7 @@ static int c_can_get_berr_counter(const * * We iterate from priv->tx_echo to priv->tx_next and check if the * packet has been transmitted, echo it back to the CAN framework. - * If we discover a not yet transmitted package, stop looking for more. + * If we discover a not yet transmitted packet, stop looking for more. */ static void c_can_do_tx(struct net_device *dev) { @@ -698,7 +698,7 @@ static void c_can_do_tx(struct net_devic for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) { msg_obj_no = get_tx_echo_msg_obj(priv); val = c_can_read_reg32(priv, &priv->regs->txrqst1); - if (!(val & (1 << msg_obj_no))) { + if (!(val & (1 << (msg_obj_no - 1)))) { can_get_echo_skb(dev, msg_obj_no - C_CAN_MSG_OBJ_TX_FIRST); stats->tx_bytes += priv->read_reg(priv, @@ -706,6 +706,8 @@ static void c_can_do_tx(struct net_devic & IF_MCONT_DLC_MASK; stats->tx_packets++; c_can_inval_msg_object(dev, 0, msg_obj_no); + } else { + break; } }
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