From patchwork Thu Oct 9 21:02:28 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 398334 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 9E730140085; Fri, 10 Oct 2014 08:11:53 +1100 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1XcL03-0003Xp-1i; Thu, 09 Oct 2014 21:11:51 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1XcKwt-0001XD-P5 for kernel-team@lists.ubuntu.com; Thu, 09 Oct 2014 21:08:35 +0000 Received: from c-76-102-4-12.hsd1.ca.comcast.net ([76.102.4.12] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1XcKry-00047e-Pa; Thu, 09 Oct 2014 21:03:30 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1XcKrx-0007DC-0N; Thu, 09 Oct 2014 14:03:29 -0700 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.13 123/163] can: flexcan: put TX mailbox into TX_INACTIVE mode after tx-complete Date: Thu, 9 Oct 2014 14:02:28 -0700 Message-Id: <1412888588-26755-124-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1412888588-26755-1-git-send-email-kamal@canonical.com> References: <1412888588-26755-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Cc: Kamal Mostafa , Marc Kleine-Budde X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.13.11.9 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Marc Kleine-Budde commit de5944883ebbedbf5adc8497659772f5da7b7d72 upstream. 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. Signed-off-by: Marc Kleine-Budde Signed-off-by: Kamal Mostafa --- 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 3a1859b..deea3a9 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -702,6 +702,9 @@ 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); }