From patchwork Thu Sep 18 10:41:00 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Kleine-Budde X-Patchwork-Id: 390755 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id E34511401F1 for ; Thu, 18 Sep 2014 20:41:32 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756906AbaIRKl2 (ORCPT ); Thu, 18 Sep 2014 06:41:28 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:37909 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756729AbaIRKlO (ORCPT ); Thu, 18 Sep 2014 06:41:14 -0400 Received: from gallifrey.ext.pengutronix.de ([2001:6f8:1178:4:5054:ff:fe8d:eefb] helo=hardanger.do.blackshift.org) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1XUZ9E-0007hM-42; Thu, 18 Sep 2014 12:41:12 +0200 From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, linux-can@vger.kernel.org, kernel@pengutronix.de, Marc Kleine-Budde , linux-stable Subject: [PATCH 6/8] can: flexcan: put TX mailbox into TX_INACTIVE mode after tx-complete Date: Thu, 18 Sep 2014 12:41:00 +0200 Message-Id: <1411036862-13255-7-git-send-email-mkl@pengutronix.de> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1411036862-13255-1-git-send-email-mkl@pengutronix.de> References: <1411036862-13255-1-git-send-email-mkl@pengutronix.de> X-SA-Exim-Connect-IP: 2001:6f8:1178:4:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org After sending a RTR frame the TX mailbox becomes a RX_EMPTY mailbox. To avoid side effects when the RX-FIFO is full, this patch puts the TX mailbox into TX_INACTIVE mode in the transmission complete interrupt handler. This, of course, leaves a race window between the actual completion of the transmission and the handling of tx-complete interrupt. However this is the best we can do without busy polling the tx complete interrupt. Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/flexcan.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 54061c4..c17ae9e 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -765,6 +765,9 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id) stats->tx_bytes += can_get_echo_skb(dev, 0); stats->tx_packets++; can_led_event(dev, CAN_LED_EVENT_TX); + /* after sending a RTR frame mailbox is in RX mode */ + flexcan_write(FLEXCAN_MB_CODE_TX_INACTIVE, + ®s->cantxfg[FLEXCAN_TX_BUF_ID].can_ctrl); flexcan_write((1 << FLEXCAN_TX_BUF_ID), ®s->iflag1); netif_wake_queue(dev); }