From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752518AbaEWF74 (ORCPT ); Fri, 23 May 2014 01:59:56 -0400 Received: from mail-bl2lp0209.outbound.protection.outlook.com ([207.46.163.209]:44805 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751919AbaEWF7x (ORCPT ); Fri, 23 May 2014 01:59:53 -0400 From: Huang Shijie To: CC: , , , Huang Shijie Subject: [PATCH 1/2 rebased] serial: imx: remove the DMA wait queue Date: Fri, 23 May 2014 12:40:40 +0800 Message-ID: <1400820040-21396-1-git-send-email-b32955@freescale.com> X-Mailer: git-send-email 1.7.8 In-Reply-To: <1400819575-20435-1-git-send-email-b32955@freescale.com> References: <1400819575-20435-1-git-send-email-b32955@freescale.com> X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:192.88.168.1;CTRY:US;IPV:CAL;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(6009001)(189002)(199002)(80022001)(44976005)(19580405001)(50986999)(77982001)(76482001)(6806004)(19580395003)(33646001)(83322001)(4396001)(74662001)(93916002)(77096999)(76176999)(87286001)(89996001)(31966008)(88136002)(62966002)(21056001)(81342001)(87936001)(81542001)(50226001)(26826002)(83072002)(79102001)(48376002)(102836001)(74502001)(47776003)(92726001)(99396002)(64706001)(92566001)(77156001)(50466002)(36756003)(20776003)(46102001)(85852003)(42262001);DIR:OUT;SFP:;SCL:1;SRVR:BY2PR03MB425;H:tx30smr01.am.freescale.net;FPR:;MLV:ovrnspm;PTR:gate-tx3.freescale.com;MX:1;A:1;LANG:en; MIME-Version: 1.0 Content-Type: text/plain X-Forefront-PRVS: 0220D4B98D Authentication-Results: spf=fail (sender IP is 192.88.168.1) smtp.mailfrom=shijie.huang@freescale.com; X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The DMA wait queue makes the code very complicated: For RX, the @->stop_rx hook does not really stop the RX; For TX, the @->stop_tx hook does not really stop the TX. The above make the imx_shutdown has to wait the RX/TX DMA to be finished. In order to make code more simple, this patch removes the DMA wait queue. By calling the dmaengine_terminate_all, this patch makes the RX stops immediately after we call the @->stop_rx hook, so does the TX. Signed-off-by: Huang Shijie --- rebase this patch on the linux-next. --- drivers/tty/serial/imx.c | 42 ++++++++++++++---------------------------- 1 files changed, 14 insertions(+), 28 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index febf400..366f169 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -225,7 +225,6 @@ struct imx_port { void *rx_buf; unsigned int tx_bytes; unsigned int dma_tx_nents; - wait_queue_head_t dma_wait; }; struct imx_port_ucrs { @@ -416,12 +415,10 @@ static void imx_stop_tx(struct uart_port *port) return; } - /* - * We are maybe in the SMP context, so if the DMA TX thread is running - * on other cpu, we have to wait for it to finish. - */ - if (sport->dma_is_enabled && sport->dma_is_txing) - return; + if (sport->dma_is_enabled && sport->dma_is_txing) { + dmaengine_terminate_all(sport->dma_chan_tx); + sport->dma_is_txing = 0; + } temp = readl(sport->port.membase + UCR1); writel(temp & ~UCR1_TXMPTYEN, sport->port.membase + UCR1); @@ -435,12 +432,10 @@ static void imx_stop_rx(struct uart_port *port) struct imx_port *sport = (struct imx_port *)port; unsigned long temp; - /* - * We are maybe in the SMP context, so if the DMA TX thread is running - * on other cpu, we have to wait for it to finish. - */ - if (sport->dma_is_enabled && sport->dma_is_rxing) - return; + if (sport->dma_is_enabled && sport->dma_is_rxing) { + dmaengine_terminate_all(sport->dma_chan_rx); + sport->dma_is_rxing = 0; + } temp = readl(sport->port.membase + UCR2); writel(temp & ~UCR2_RXEN, sport->port.membase + UCR2); @@ -497,12 +492,6 @@ static void dma_tx_callback(void *data) dev_dbg(sport->port.dev, "we finish the TX DMA.\n"); uart_write_wakeup(&sport->port); - - if (waitqueue_active(&sport->dma_wait)) { - wake_up(&sport->dma_wait); - dev_dbg(sport->port.dev, "exit in %s.\n", __func__); - return; - } } static void imx_dma_tx(struct imx_port *sport) @@ -875,10 +864,6 @@ static void imx_rx_dma_done(struct imx_port *sport) writel(temp, sport->port.membase + UCR1); sport->dma_is_rxing = 0; - - /* Is the shutdown waiting for us? */ - if (waitqueue_active(&sport->dma_wait)) - wake_up(&sport->dma_wait); } /* @@ -1025,8 +1010,6 @@ static void imx_enable_dma(struct imx_port *sport) { unsigned long temp; - init_waitqueue_head(&sport->dma_wait); - /* set UCR1 */ temp = readl(sport->port.membase + UCR1); temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN | @@ -1218,10 +1201,13 @@ static void imx_shutdown(struct uart_port *port) unsigned long flags; if (sport->dma_is_enabled) { - /* We have to wait for the DMA to finish. */ - wait_event(sport->dma_wait, - !sport->dma_is_rxing && !sport->dma_is_txing); + /* + * The upper layer may does not call the @->stop_tx and + * @->stop_rx, so we call them ourselves. + */ + imx_stop_tx(port); imx_stop_rx(port); + imx_disable_dma(sport); imx_uart_dma_exit(sport); } -- 1.7.8