From mboxrd@z Thu Jan 1 00:00:00 1970 From: AnilKumar Ch Subject: [RESEND PATCH v3 1/5] can: c_can: fix "BUG! echo_skb is occupied!" during transmit Date: Wed, 23 May 2012 15:06:24 +0530 Message-ID: <1337765788-1169-2-git-send-email-anilkumar@ti.com> References: <1337765788-1169-1-git-send-email-anilkumar@ti.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from comal.ext.ti.com ([198.47.26.152]:33394 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751212Ab2EWJhM (ORCPT ); Wed, 23 May 2012 05:37:12 -0400 In-Reply-To: <1337765788-1169-1-git-send-email-anilkumar@ti.com> Sender: linux-can-owner@vger.kernel.org List-ID: To: wg@grandegger.com, mkl@pengutronix.de, linux-can@vger.kernel.org Cc: anantgole@ti.com, nsekhar@ti.com, AnilKumar Ch This patch fixes an issue with transmit routine, which causes "can_put_echo_skb: BUG! echo_skb is occupied!" messgae 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 --- Link to previous submission http://marc.info/?t=133491608500003&r=1&w=2 drivers/net/can/c_can/c_can.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c index 536bda0..9ac28df 100644 --- 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 struct net_device *dev, * * 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_device *dev) 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_device *dev) & IF_MCONT_DLC_MASK; stats->tx_packets++; c_can_inval_msg_object(dev, 0, msg_obj_no); + } else { + break; } } -- 1.7.0.4