From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755344AbaK0I74 (ORCPT ); Thu, 27 Nov 2014 03:59:56 -0500 Received: from mail.kernel.org ([198.145.19.201]:42323 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755119AbaK0Isw (ORCPT ); Thu, 27 Nov 2014 03:48:52 -0500 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Marc Kleine-Budde , Zefan Li Subject: [PATCH 3.4 57/91] can: flexcan: put TX mailbox into TX_INACTIVE mode after tx-complete Date: Thu, 27 Nov 2014 16:42:40 +0800 Message-Id: <1417077794-9299-57-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1417077368-9217-1-git-send-email-lizf@kernel.org> References: <1417077368-9217-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marc Kleine-Budde 3.4.105-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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 [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li --- 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 681fb9c..b523e65 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -633,6 +633,9 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id) if (reg_iflag1 & (1 << FLEXCAN_TX_BUF_ID)) { stats->tx_bytes += can_get_echo_skb(dev, 0); stats->tx_packets++; + /* 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); } -- 1.9.1