From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752983AbbAZAKY (ORCPT ); Sun, 25 Jan 2015 19:10:24 -0500 Received: from mail.kmu-office.ch ([178.209.48.109]:46018 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751146AbbAZAKV (ORCPT ); Sun, 25 Jan 2015 19:10:21 -0500 From: Stefan Agner To: gregkh@linuxfoundation.org Cc: jslaby@suse.cz, jingchang.lu@freescale.com, shawn.guo@linaro.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, stefan@agner.ch Subject: [PATCH] tty: serial: fsl_lpuart: terminate DMA on buffer flush Date: Mon, 26 Jan 2015 01:10:16 +0100 Message-Id: <1422231016-27793-1-git-send-email-stefan@agner.ch> X-Mailer: git-send-email 2.2.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On uart buffer flush, serial core resets the circular buffer. If a DMA transfer is in progress at that time, the callback lpuart_dma_tx_complete will move buffer's tail unconditionally, hence tail moves beyond head. Use the flush_buffer hook to terminate the DMA imeaditely and avoid lpuart_dma_tx_complete being called in this situation. This bug often showed up while shutdown and lead to duplicate serial console output. Signed-off-by: Stefan Agner --- drivers/tty/serial/fsl_lpuart.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index e95c497..7615b5d 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -454,6 +454,15 @@ static int lpuart_dma_rx(struct lpuart_port *sport) return 0; } +static void lpuart_flush_buffer(struct uart_port *port) +{ + struct lpuart_port *sport = container_of(port, struct lpuart_port, port); + if (sport->lpuart_dma_tx_use) { + dmaengine_terminate_all(sport->dma_tx_chan); + sport->dma_tx_in_progress = 0; + } +} + static void lpuart_dma_rx_complete(void *arg) { struct lpuart_port *sport = arg; @@ -1519,6 +1528,7 @@ static struct uart_ops lpuart_pops = { .release_port = lpuart_release_port, .config_port = lpuart_config_port, .verify_port = lpuart_verify_port, + .flush_buffer = lpuart_flush_buffer, }; static struct uart_ops lpuart32_pops = { @@ -1537,6 +1547,7 @@ static struct uart_ops lpuart32_pops = { .release_port = lpuart_release_port, .config_port = lpuart_config_port, .verify_port = lpuart_verify_port, + .flush_buffer = lpuart_flush_buffer, }; static struct lpuart_port *lpuart_ports[UART_NR]; -- 2.2.2